Laminated Sheet

Abstract

To provide a laminated sheet that can be accurately aligned to form vias or reliably acquire information about a product.SOLUTION: A laminated sheet 13 includes: a sheet-shaped inductor 2 provided with a plurality of wires 7 and a magnetic layer 8 that buries the plurality of wires 7; and a mark-formable layer 15 disposed on one side of the inductor 2 in the thickness direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminated sheet. [Background technology]

[0002] Conventionally, sheet-shaped inductors are known to be mounted in electronic devices. As such an inductor, an inductor including a wiring and a magnetic layer covering the wiring has been proposed (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-220618 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in some cases, vias are formed in the magnetic layer to electrically connect the wiring to electronic devices. In this case, it is necessary to align the inductor to accurately recognize the position of the wiring in a plan view. However, the technique disclosed in Patent Document 1 has the drawback that the inductor cannot be aligned with high precision.

[0005] Furthermore, there is a demand from users to obtain information about inductors to be installed in electronic devices before the inductors are installed. However, the inductor disclosed in Patent Document 1 does not include the above-mentioned information. This creates the problem that users cannot obtain the inductor information in advance.

[0006] The present invention provides a laminated sheet that can be aligned with high precision to form vias or reliably obtain information about a product. [Means for solving the problem]

[0007] The present invention (1) includes a laminated sheet characterized by comprising a sheet-like inductor having a plurality of wirings and a magnetic layer in which the plurality of wirings are embedded, and a mark-formable layer arranged on one surface of the inductor in the thickness direction.

[0008] This laminated sheet includes a mark-formable layer, and therefore, by forming marks on the mark-formable layer, the laminated sheet can be aligned based on the marks to form vias, or information about the product can be recognized based on the marks to reliably obtain such information.

[0009] The present invention (2) includes the laminate sheet according to (1), wherein the material of the mark-formable layer is a resin composition.

[0010] In this laminate sheet, the material of the mark-formable layer is a resin composition, so that marks can be easily formed.

[0011] The present invention (3) includes the laminate sheet according to (2), in which the resin composition is a thermosetting resin composition and satisfies at least one of the following tests (a) to (e):

[0012] Test (a): The laminated sheet is cut into a 3 cm square to prepare a sample, and its relative permeability μ1 at a frequency of 10 MHz is measured. The sample is then immersed in 200 mL of a copper sulfate plating solution containing 66 g / L of copper sulfate pentahydrate, 180 g / L of sulfuric acid, 50 ppm of chlorine, and top lutina at 25°C for 120 minutes, after which the relative permeability μ2 of the sample at a frequency of 10 MHz is measured. The rate of change in permeability before and after immersion is calculated using the following formula. As a result, the rate of change in the sample's permeability is 5% or less.

[0013] Permeability change rate (%) = |μ1-μ2| / μ1×100 Test (b): The laminated sheet is cut into a 3 cm square to prepare a sample, and its relative permeability μ3 at a frequency of 10 MHz is measured. The sample is then immersed in 200 mL of an acid-activated aqueous solution containing 55 g / L of sulfuric acid at 25°C for 1 minute, and the relative permeability μ4 of the sample at a frequency of 10 MHz is then measured. The rate of change in permeability before and after immersion is calculated using the following formula. As a result, the rate of change in the sample's permeability is 5% or less.

[0014] Permeability change rate (%) = |μ3-μ4| / μ3×100 Test (c): The laminated sheet is cut into a 3 cm square to prepare a sample, and its relative permeability μ5 at a frequency of 10 MHz is measured. The sample is then immersed in 200 mL of Securigant P Reduction Solution manufactured by Atotech Japan at 45°C for 5 minutes, after which the relative permeability μ6 of the sample at a frequency of 10 MHz is measured. The rate of change in permeability before and after immersion is calculated using the following formula. As a result, the rate of change in the sample's permeability is 5% or less.

[0015] Permeability change rate (%) = |μ5-μ6| / μ5×100 Test (d): The laminated sheet is cut into a 3 cm square to create a sample, and its relative permeability μ7 at a frequency of 10 MHz is measured. The sample is then immersed in 200 mL of Concentrate Compact CP manufactured by Atotech Japan at 80°C for 15 minutes, after which the relative permeability μ8 of the sample at a frequency of 10 MHz is measured. The rate of change in permeability before and after immersion is calculated using the following formula. As a result, the rate of change in the sample's permeability is 5% or less.

[0016] Permeability change rate (%) = |μ7-μ8| / μ7×100 Test (e): The laminated sheet is cut into a 3 cm square to prepare a sample, and its relative permeability μ9 at a frequency of 10 MHz is measured. The sample is then immersed in 200 mL of Swelling Dip Securigant P manufactured by Atotech Japan at 60°C for 5 minutes, after which the relative permeability μ10 of the sample at a frequency of 10 MHz is measured. The rate of change in permeability before and after immersion is calculated using the following formula. As a result, the rate of change in the sample's permeability is 5% or less.

[0017] Permeability change rate (%) = |μ9-μ10| / μ9×100 This laminate sheet satisfies at least one of the tests (a) to (e), and therefore has excellent stability against processing using chemical solutions. [Effects of the Invention]

[0018] The laminated sheet of the present invention allows for accurate alignment to form vias or to reliably obtain information about a product. [Brief explanation of the drawings]

[0019] [Figure 1] 1A to 1C are plan views of the manufacturing process and processing aspect of one embodiment of the laminate sheet of the present invention, where FIG. 1A shows the laminate sheet, FIG. 1B shows a step of forming marks, and FIG. 1C shows a step of forming vias. [Figure 2] 2A to 2D are front cross-sectional views of the manufacturing process and processing aspect of one embodiment of the laminated sheet of the present invention, where FIG. 2A shows an inductor, FIG. 2B shows a laminated sheet, FIG. 2C shows a step of forming a mark, and FIG. 2D shows a step of forming a via. [Figure 3] FIG. 3 is an enlarged cross-sectional view of a modified mark. [Figure 4] FIG. 4 is an enlarged cross-sectional view of a modified mark. [Figure 5] FIG. 5 is an enlarged cross-sectional view of a modified mark. [Figure 6] FIG. 6 is a plan view of a modified example of the mark. [Figure 7]FIG. 7 is a plan view of a modified example of the marked laminated sheet shown in FIG. 1B (a modified example in which the marks are lot numbers). DETAILED DESCRIPTION OF THE INVENTION

[0020] <One embodiment> One embodiment of the laminate sheet of the present invention will be described with reference to FIGS. 1A and 2B.

[0021] The laminated sheet 13 has a predetermined thickness and a sheet shape extending in a plane direction perpendicular to the thickness direction. For example, the laminated sheet 13 has a generally rectangular shape in a plan view. The laminated sheet 13 includes a sheet-like inductor 2 and a mark-formable layer 15.

[0022] In plan view, the inductor 2 has the same outer shape as the laminated sheet 13. Specifically, in plan view, the inductor 2 has a substantially rectangular shape including four sides 5.

[0023] The inductor 2 also includes a plurality of wires 7 and a magnetic layer 8.

[0024] The multiple wirings 7 are adjacent to each other with a gap therebetween. The multiple wirings 7 are parallel to each other. The multiple wirings 7 extend in a direction perpendicular to the direction in which they are adjacent to each other and the thickness direction. The shape, dimensions, configuration, material, formulation (filling rate, content ratio, etc.) of the wirings 7 are described, for example, in JP 2019-220618 A. Preferably, the wirings 7 have a substantially circular shape in a cross section perpendicular to the direction along the wirings 7, with a lower limit of the diameter being, for example, 25 μm and an upper limit of the diameter being, for example, 2,000 μm. The wirings 7 preferably include a conductor wire and an insulating film covering the circumferential surface of the conductor wire. The lower limit of the distance between adjacent wirings 7 is, for example, 10 μm, preferably 50 μm, and the upper limit of the distance between adjacent wirings 7 is, for example, 5,000 μm, preferably 3,000 μm. The upper limit of the ratio of the diameter of the wires 7 to the spacing between adjacent wires 7 (diameter / spacing) is, for example, 200, or preferably 50, and the lower limit is, for example, 0.01, or preferably 0.1.

[0025] The magnetic layer 8 improves the inductance of the laminate sheet 13. In a plan view, the magnetic layer 8 has the same outer shape as the inductor 2. The magnetic layer 8 has a plate shape extending in the plane direction. In a cross-sectional view, the magnetic layer 8 has a plurality of wirings 7 embedded therein. The magnetic layer 8 has one surface 9, another surface 10, and an inner peripheral surface 11.

[0026] One surface 9 forms one surface of the magnetic layer 8 in the thickness direction.

[0027] The other surface 10 forms the other surface in the thickness direction of the magnetic layer 8. The other surface 10 is spaced apart from the one surface 9 on the other side in the thickness direction.

[0028] The inner circumferential surface 11 is spaced apart from the one surface 9 and the other surface 10 in the thickness direction. The inner circumferential surface 11 is located between the one surface 9 and the other surface 10 in the thickness direction. The inner circumferential surface 11 is also located between two opposing outer surfaces 18 in the direction in which the multiple wirings 7 are adjacent to each other. The inner circumferential surface 11 contacts the outer surfaces of the wirings 7.

[0029] The magnetic layer 8 includes a binder and magnetic particles. Specifically, the material of the magnetic layer 8 is a magnetic composition containing a binder and magnetic particles.

[0030] Examples of binders include thermoplastic resins such as acrylic resins and thermosetting resins such as epoxy resin compositions. Acrylic resins include, for example, carboxyl group-containing acrylic ester copolymers. Epoxy resin compositions include, for example, a base epoxy resin (such as cresol novolac epoxy resin), an epoxy resin curing agent (such as phenolic resin), and an epoxy resin curing accelerator (such as an imidazole compound). As binders, thermoplastic resins and thermosetting resins can be used alone or in combination, and preferably, a thermoplastic resin and a thermosetting resin are used in combination. The volume ratio of the binder in the magnetic composition is the remainder of the volume ratio of the magnetic particles, which will be described later.

[0031] The magnetic particles are dispersed in, for example, a binder. In this embodiment, the magnetic particles have, for example, a substantially flat shape. The substantially flat shape includes a substantially plate shape. The magnetic particles may have a substantially spherical shape or a substantially needle shape. Preferably, the magnetic particles have a substantially flat shape.

[0032] When the magnetic particles have a substantially flat shape, the lower limit of the flatness (degree of flatness) is, for example, 8, or preferably 15, and the upper limit is, for example, 500, or preferably 450. The flatness is calculated, for example, as the aspect ratio obtained by dividing the median diameter of the magnetic particles by the average thickness of the magnetic particles.

[0033] The lower limit of the median diameter of the magnetic particles is, for example, 3.5 μm, preferably 10 μm, and the upper limit is, for example, 200 μm, preferably 150 μm. When the magnetic particles have a substantially flat shape, the lower limit of the average thickness is, for example, 0.1 μm, preferably 0.2 μm, and the upper limit is, for example, 3.0 μm, preferably 2.5 μm.

[0034] The material of the magnetic particles is a metal. Examples of the metal include magnetic materials such as soft magnetic materials and hard magnetic materials. Preferably, a soft magnetic material is used from the viewpoint of ensuring good inductance.

[0035] Examples of soft magnetic materials include single metal bodies containing one type of metal element in a pure substance state, and alloy bodies that are eutectic bodies (mixtures) of one or more types of metal elements (first metal elements) with one or more types of metal elements (second metal elements) and / or non-metal elements (carbon, nitrogen, silicon, phosphorus, etc.). These can be used alone or in combination.

[0036] An example of a single metal body is a metal element consisting of only one type of metal element (first metal element). The first metal element is appropriately selected from metal elements that can be contained as the first metal element in a soft magnetic body, such as iron (Fe), cobalt (Co), nickel (Ni), and others.

[0037] Furthermore, examples of the single metal body include a core containing only one type of metal element and a surface layer containing an inorganic and / or organic substance that modifies part or all of the surface of the core, such as a form obtained by decomposing (e.g., thermally decomposing) an organometallic compound or inorganic metal compound containing the first metal element. More specifically, the latter form includes iron powder (sometimes referred to as carbonyl iron powder) obtained by thermally decomposing an organoiron compound (e.g., carbonyl iron) containing iron as the first metal element. The location of the layer containing the inorganic and / or organic substance that modifies the part containing only one type of metal element is not limited to the surface as described above. The organometallic compound or inorganic metal compound from which the single metal body can be obtained is not particularly limited and can be appropriately selected from known or commonly used organometallic compounds or inorganic metal compounds that can be used to obtain a single metal body of a soft magnetic material.

[0038] The alloy body is a eutectic of one or more metal elements (first metal elements) and one or more metal elements (second metal elements) and / or non-metal elements (carbon, nitrogen, silicon, phosphorus, etc.), and is not particularly limited as long as it can be used as an alloy body of a soft magnetic material.

[0039] The first metallic element is an essential element in the alloy body, and examples thereof include iron (Fe), cobalt (Co), nickel (Ni), etc. If the first metallic element is Fe, the alloy body is an Fe-based alloy, if the first metallic element is Co, the alloy body is a Co-based alloy, and if the first metallic element is Ni, the alloy body is a Ni-based alloy.

[0040] The second metallic element is an element (secondary component) secondarily contained in the alloy body, and is a metallic element that is compatible (eutectic) with the first metallic element, and examples thereof include iron (Fe) (when the first metallic element is other than Fe), cobalt (Co) (when the first metallic element is other than Co), nickel (Ni) (when the first metallic element is other than Ni), chromium (Cr), aluminum (Al), silicon (Si), copper (Cu), silver (Ag), manganese (Mn), calcium (Ca), barium (B). Examples of rare earth elements include aluminum (Ba), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), molybdenum (Mo), tungsten (W), ruthenium (Ru), rhodium (Rh), zinc (Zn), gallium (Ga), indium (In), germanium (Ge), tin (Sn), lead (Pb), scandium (Sc), yttrium (Y), strontium (Sr), and various rare earth elements. These can be used alone or in combination of two or more.

[0041] The non-metallic element is an element (secondary component) secondarily contained in the alloy body, and is a non-metallic element that is compatible (eutectic) with the first metallic element, such as boron (B), carbon (C), nitrogen (N), silicon (Si), phosphorus (P), sulfur (S), etc. These may be used alone or in combination of two or more.

[0042] Examples of Fe-based alloys include magnetic stainless steel (Fe-Cr-Al-Si alloy) (including electromagnetic stainless steel), sendust (Fe-Si-Al alloy) (including super sendust), permalloy (Fe-Ni alloy), Fe-Ni-Mo alloy, Fe-Ni-Mo-Cu alloy, Fe-Ni-Co alloy, Fe-Cr alloy, Fe-Cr-Al alloy, Fe-Ni-Cr alloy, Fe-Ni-Cr-Si alloy, silicon copper (Fe-Cu-Si alloy), Fe-Si alloy, Fe-Si-B(-Cu-Nb) alloy, Fe-B-Si-Cr alloy, Fe-S Examples of such alloys include i-Cr-Ni alloys, Fe-Si-Cr alloys, Fe-Si-Al-Ni-Cr alloys, Fe-Ni-Si-Co alloys, Fe-N alloys, Fe-C alloys, Fe-B alloys, Fe-P alloys, ferrites (including stainless steel ferrites, as well as soft ferrites such as Mn-Mg ferrites, Mn-Zn ferrites, Ni-Zn ferrites, Ni-Zn-Cu ferrites, Cu-Zn ferrites, and Cu-Mg-Zn ferrites), permendur (Fe-Co alloys), Fe-Co-V alloys, and Fe-based amorphous alloys.

[0043] Examples of the alloy body, Co-based alloys, include Co-Ta-Zr and cobalt (Co)-based amorphous alloys.

[0044] An example of an alloy body, a Ni-based alloy, is a Ni-Cr alloy.

[0045] A more detailed formulation of the magnetic composition described above is described in, for example, JP 2014-165363 A.

[0046] The lower limit of the volume fraction of the magnetic particles in the magnetic composition is, for example, 40 volume %, preferably 50 volume %, more preferably 60 volume %, and the upper limit is, for example, 95 volume %, preferably 90 volume %.

[0047] The lower limit of the thickness of the inductor 2 is, for example, 30 μm, or preferably 40 μm, and the upper limit of the thickness of the inductor 2 is, for example, 2,500 μm, or preferably 2,000 μm.

[0048] The lower limit of the ratio of the thickness of the inductor 2 to the thickness of the laminated sheet 13 is, for example, 0.1, preferably 0.3, more preferably 0.5, and the upper limit is, for example, 0.9, preferably 0.8, more preferably 0.7.

[0049] The mark-formable layer 15 is a layer on which marks 4, which will be described next, can be formed. In other words, the mark-formable layer 15 is a layer on which marks 4 have not yet been formed, and is not the mark layer 3 on which marks 4 have already been formed. The mark-formable layer 15 has a sheet shape extending in the surface direction. Specifically, the mark-formable layer 15 has the same outer shape as the laminated sheet 13 in a planar view. The mark-formable layer 15 is disposed on one surface 9 of the magnetic layer 8. Specifically, the mark-formable layer 15 is in contact with the entire one surface 9.

[0050] The material of the mark-formable layer 15 is not particularly limited and may be, for example, a resin composition, a metal, or a ceramic, and is preferably a resin composition. If the material of the mark-formable layer 15 is a resin composition, it is easy to form the marks 4 described below.

[0051] The resin composition contains, for example, a resin as an essential component and particles as an optional component.

[0052] Examples of the resin include curable resins such as thermosetting resins and active energy ray curable resins, and plastic resins such as thermoplastic resins.

[0053] The curable resin is preferably a thermosetting resin. If a thermosetting resin is used, the mark-formable layer 15 can contain a cured product of the thermosetting resin, which can reduce the rate of change in magnetic permeability of the laminate sheet 13 in an immersion test described below. The thermosetting resin contains a base agent, a curing agent, and a curing accelerator.

[0054] Examples of the base resin include epoxy resins and silicone resins, and preferably epoxy resins. Examples of epoxy resins include bifunctional epoxy resins such as bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, modified bisphenol A epoxy resins, modified bisphenol F epoxy resins, modified bisphenol S epoxy resins, and biphenyl epoxy resins, and polyfunctional epoxy resins having three or more functional groups such as phenol novolac epoxy resins, cresol novolac epoxy resins, trishydroxyphenylmethane epoxy resins, tetraphenylolethane epoxy resins, and dicyclopentadiene epoxy resins. These epoxy resins can be used alone or in combination of two or more. Preferably, bifunctional epoxy resins are used, and more preferably, bisphenol A epoxy resins.

[0055] The lower limit of the epoxy equivalent of the epoxy resin is, for example, 10 g / eq., and the upper limit is, for example, 1,000 g / eq.

[0056] If the base resin is an epoxy resin, examples of the curing agent include phenolic resins and isocyanate resins. Examples of phenolic resins include polyfunctional phenolic resins such as phenol novolac resins, cresol novolac resins, phenol aralkyl resins, phenol biphenylene resins, dicyclopentadiene-type phenolic resins, and resol resins. These can be used alone or in combination of two or more. Preferred phenolic resins include phenol novolac resins and phenol biphenylene resins. If the base resin is an epoxy resin and the curing agent is a phenolic resin, the lower limit of the total number of hydroxyl groups in the phenolic resin per equivalent of epoxy groups in the epoxy resin is, for example, 0.7 equivalents, preferably 0.9 equivalents, and the upper limit is, for example, 1.5 equivalents, preferably 1.2 equivalents. Specifically, the lower limit of the number of parts by mass of the curing agent per 100 parts by mass of the base resin is, for example, 1 part by mass, or, for example, 50 parts by mass.

[0057] The curing accelerator is a catalyst (thermal curing catalyst) (preferably an epoxy resin curing accelerator) that accelerates the curing of the base resin, and examples thereof include organic phosphorus compounds, such as imidazole compounds such as 2-phenyl-4-methyl-5-hydroxymethylimidazole (2P4MHZ). The lower limit of the number of parts by mass of the curing accelerator is, for example, 0.05 parts by mass, and the upper limit is, for example, 5 parts by mass, relative to 100 parts by mass of the base resin.

[0058] Examples of the thermoplastic resin include acrylic resin, polyester resin, thermoplastic polyurethane resin, etc. The thermoplastic resin also includes hydrophilic polymers.

[0059] As the resin, either a hardening resin or a plastic resin can be used alone, or they can be used in combination.

[0060] The lower limit of the mass proportion of the resin in the resin composition is, for example, 10 mass %, or preferably 30 mass %, and the upper limit is, for example, 90 mass %, or preferably 75 mass %.

[0061] The particles are at least one type selected from the group consisting of first particles and second particles.

[0062] The first particles have, for example, a substantially spherical shape. The lower limit of the median diameter of the first particles is, for example, 1 μm, preferably 5 μm, and the upper limit of the median diameter of the first particles is, for example, 250 μm, preferably 200 μm. The median diameter of the first particles is determined using a laser diffraction particle size distribution analyzer. Alternatively, the median diameter of the first particles can be determined, for example, by binarization processing based on cross-sectional observation.

[0063] The material of the first particles is not particularly limited. Examples of the material of the first particles include metals, inorganic compounds, organic compounds, and simple non-metallic elements, and from the viewpoint of reliably forming the marks 4, inorganic compounds and simple non-metallic elements are preferred.

[0064] The inorganic compound is contained in the resin composition when the mark-formable layer 15 is to function as an ink-receiving layer. Examples of the inorganic compound include inorganic fillers, specifically silica and alumina, and preferably silica.

[0065] The non-metallic element is contained in the resin composition when the mark-formable layer 15 is to function as a laser discoloration layer. Examples of the non-metallic element include carbon and silicon, preferably carbon, and more preferably carbon black.

[0066] Specifically, the first particles are preferably spherical silica, and are preferably spherical carbon black.

[0067] The second particles have, for example, a substantially flat shape, which includes a substantially plate shape.

[0068] The lower limit of the flattening ratio (flatness) of the second particles is, for example, 8, or preferably 15, and the upper limit is, for example, 500, or preferably 450. The flattening ratio of the second particles is calculated using the same method as the flattening ratio of the magnetic particles in the magnetic layer 8 described above.

[0069] The lower limit of the median diameter of the second particles is, for example, 1 μm, or preferably 5 μm, and the upper limit of the median diameter of the second particles is, for example, 250 μm, or preferably 200 μm. The median diameter of the second particles is determined in the same manner as that of the first particles.

[0070] The lower limit of the average thickness of the second particles is, for example, 0.1 μm, or preferably 0.2 μm, and the upper limit is, for example, 3.0 μm, or preferably 2.5 μm.

[0071] The material of the second particles is an inorganic compound, such as a thermally conductive compound such as boron nitride.

[0072] Specifically, the second particles are preferably flat boron nitride particles.

[0073] The resin composition may contain a single type of first particles and a second particle, or may contain both of them.

[0074] The lower limit of the number of parts by mass of the particles (first particles and / or second particles) per 100 parts by mass of the resin is, for example, 10 parts by mass, preferably 50 parts by mass, and the upper limit is, for example, 2,000 parts by mass, preferably 1,500 parts by mass. The lower limit of the particle content in the resin composition is, for example, 10% by mass, and the upper limit is, for example, 90% by mass. When both the first particles and the second particles are contained in the resin composition, the lower limit of the number of parts by mass of the second particles per 100 parts by mass of the first particles is, for example, 30 parts by mass, and the upper limit is, for example, 300 parts by mass.

[0075] Since particles are an optional component in the resin composition, the resin composition does not necessarily need to contain particles.

[0076] The lower limit of the thickness of the mark-formable layer 15 is, for example, 1 μm, or preferably 10 μm, and the upper limit is, for example, 1,000 μm, or preferably 100 μm. The lower limit of the ratio of the thickness of the mark-formable layer 15 to the thickness of the laminated sheet 13 is, for example, 0.001, preferably 0.005, or more preferably 0.01, and the upper limit is, for example, 0.5, preferably 0.3, or more preferably 0.1.

[0077] The lower limit of the thickness of the laminated sheet 13 is, for example, 40 μm, or preferably 50 μm, and the upper limit of the thickness of the inductor 2 is, for example, 3,000 μm, or preferably 2,500 μm.

[0078] Next, a method for producing and processing the laminate sheet 1 will be described with reference to FIGS. 1A to 2D.

[0079] In this method, first, an inductor 2 is prepared as shown in Fig. 2A. The inductor 2 is prepared by, for example, the method described in Japanese Patent Application Laid-Open No. 2019-220618.

[0080] Next, in this method, as shown in FIGS. 1A and 2B, a mark-formable layer 15 is disposed on one surface of the inductor 2 in the thickness direction.

[0081] To dispose the mark-formable layer 15 on the inductor 2, first, a mark-formable sheet 14 is prepared. The mark-formable sheet 14 is the sheet before the mark-formable layer 15 is disposed on one side 9 of the inductor 2, and its material is the same as the material of the mark-formable layer 15. To prepare the mark-formable sheet 14, a solvent is further mixed with the above-mentioned material to prepare a varnish, which is then applied to the surface of a release sheet (not shown) and dried. When the resin contains a thermosetting resin, the thermosetting resin is in the B-stage or C-stage.

[0082] Next, the mark-formable sheet 14 is attached to one thickness-wise surface of the inductor 2. Specifically, the other thickness-wise surface of the mark-formable sheet 14 is brought into contact with one thickness-wise surface of the inductor 2. As a result, the mark-formable sheet 14 is formed on the mark-formable layer 15 in a state in contact with one surface 9 of the magnetic layer 8. Alternatively, the mark-formable layer 15 can be formed by applying varnish directly to one surface 9 of the inductor 2.

[0083] Thereafter, if the resin contains a B-stage thermosetting resin, the thermosetting resin is converted to a C-stage by heating.

[0084] As a result, the mark-formable layer 15 is disposed (laminated) on one surface in the thickness direction of the inductor 2. Preferably, the mark-formable layer 15 is adhered to one surface 9 of the magnetic layer 8.

[0085] This provides the laminated sheet 13 that includes the inductor 2 and the mark-formable layer 15. The laminated sheet 13 preferably includes only the inductor 2 and the mark-formable layer 15.

[0086] This laminated sheet 13 does not yet have marks 4 but has a mark-formable layer 15 for forming marks 4, and is a device that can be distributed independently and is industrially applicable.

[0087] This laminate sheet 13 satisfies at least one of the tests (a) to (e), for example.

[0088] Test (a): A sample is prepared by cutting the laminate sheet 13 into a 3 cm square, and its relative permeability μ1 at a frequency of 10 MHz is measured. The sample is then immersed in 200 mL of copper sulfate plating solution containing 66 g / L of copper sulfate pentahydrate, 180 g / L of sulfuric acid, 50 ppm of chlorine, and top lutina at 25°C for 120 minutes, and the relative permeability μ2 of the sample at a frequency of 10 MHz is then measured. The rate of change in permeability before and after immersion is calculated using the following formula. As a result, the rate of change in the sample's permeability is 5% or less.

[0089] Permeability change rate (%) = |μ1-μ2| / μ1×100 Test (b): A sample is prepared by cutting the laminated sheet 13 into a 3 cm square, and its relative permeability μ3 at a frequency of 10 MHz is measured. The sample is then immersed in 200 mL of an acid-activated aqueous solution containing 55 g / L of sulfuric acid at 25°C for 1 minute, and the relative permeability μ4 of the sample at a frequency of 10 MHz is then measured. The rate of change in permeability before and after immersion is calculated using the following formula. As a result, the rate of change in the sample's permeability is 5% or less.

[0090] Permeability change rate (%) = |μ3-μ4| / μ3×100 Test (c): A sample is prepared by cutting the laminated sheet 13 into a 3 cm square, and its relative permeability μ5 at a frequency of 10 MHz is measured. The sample is then immersed in 200 mL of Securigant P Reduction Solution manufactured by Atotech Japan at 45°C for 5 minutes, after which the relative permeability μ6 of the sample at a frequency of 10 MHz is measured. The rate of change in permeability before and after immersion is calculated using the following formula. As a result, the rate of change in the sample's permeability is 5% or less.

[0091] Permeability change rate (%) = |μ5-μ6| / μ5×100 Test (d): A sample is prepared by cutting the laminated sheet 13 into a 3 cm square, and its relative permeability μ7 at a frequency of 10 MHz is measured. The sample is then immersed in 200 mL of Concentrate Compact CP manufactured by Atotech Japan at 80°C for 15 minutes, after which the relative permeability μ8 of the sample at a frequency of 10 MHz is measured. The rate of change in permeability before and after immersion is calculated using the following formula. As a result, the rate of change in the sample's permeability is 5% or less.

[0092] Permeability change rate (%) = |μ7-μ8| / μ7×100 Test (e): A sample is prepared by cutting the laminated sheet 13 into a 3 cm square, and its relative permeability μ9 at a frequency of 10 MHz is measured. The sample is then immersed in 200 mL of Swelling Dip Securigant P manufactured by Atotech Japan at 60°C for 5 minutes, after which the relative permeability μ10 of the sample at a frequency of 10 MHz is measured. The rate of change in permeability before and after immersion is calculated using the following formula. As a result, the rate of change in the sample's permeability is 5% or less.

[0093] Permeability change rate (%) = |μ9-μ10| / μ9×100 In the case where test (a) is satisfied, the upper limit of the rate of change in magnetic permeability of the sample in test (a) is preferably 4%, more preferably 3%.

[0094] If test (a) is satisfied, the laminate sheet 13 has excellent stability against immersion in a copper sulfate solution for electrolytic copper plating.

[0095] In the case where test (b) is satisfied, the upper limit of the rate of change in magnetic permeability of the sample in test (b) is preferably 4%, more preferably 3%.

[0096] If test (b) is satisfied, the laminate sheet 13 has excellent stability against immersion in an acid activation solution.

[0097] In the case where test (c) is satisfied, the upper limit of the rate of change in magnetic permeability of the sample in test (c) is preferably 4%, more preferably 3%.

[0098] In test (c), Reduction Solution Securiganth P manufactured by Atotech Japan Ltd. contains an aqueous sulfuric acid solution and is used as a neutralizing liquid (neutralizing agent or aqueous solution for neutralization). Therefore, if test (c) is satisfied, the laminate sheet 13 has excellent stability against immersion in a neutralizing liquid.

[0099] In the case where test (d) is satisfied, the upper limit of the rate of change in magnetic permeability of the sample in test (d) is preferably 4%, more preferably 3%.

[0100] The Concentrate Compact CP manufactured by Atotech Japan Co., Ltd. in test (d) contains a potassium permanganate solution. Therefore, if test (d) is satisfied, the laminate sheet 13 has excellent stability against immersion in a potassium permanganate solution for desmearing (cleaning).

[0101] In the case where test (e) is satisfied, the upper limit of the rate of change in magnetic permeability of the sample in test (e) is preferably 4%, more preferably 3%.

[0102] In test (e), Swelling Dip Securigant P manufactured by Atotech Japan is an aqueous solution containing glycol ethers and sodium hydroxide, and is used as the swelling liquid. Therefore, if test (e) is satisfied, the laminate sheet 13 has excellent stability against immersion in a swelling liquid.

[0103] Preferably, all of tests (a) to (e) are satisfied, and therefore the laminate sheet 13 has excellent stability against immersion in a copper sulfate solution for electrolytic copper plating, an acid activation solution, a neutralizing solution, a potassium permanganate solution for desmearing (cleaning), and a swelling solution, and has excellent stability against various processes using these solutions.

[0104] Thereafter, as shown in FIGS. 1B and 2C, for example, marks 4 are formed in the mark-formable layer 15.

[0105] The method for forming the marks 4 is not particularly limited, and examples thereof include drilling and etching.

[0106] The marks 4 are, for example, marks that indicate the positional information of the plurality of wirings 7 in the laminated sheet 13. The marks 4 are also alignment marks for forming vias 16 in the laminated sheet 13, which will be described next.

[0107] The marks 4 are formed in the mark-formable layer 15. Specifically, the marks 4 are arranged on one surface in the thickness direction of the mark-formable layer 15. For example, each of the marks 4 is formed in each of four corners 6 defined by four sides 5 of the mark-formable layer 15. The marks 4 have, for example, a roughly cross shape in plan view.

[0108] The mark 4 is a recess extending from one surface of the mark-formable layer 15 in the thickness direction toward the other surface in the thickness direction, and extending partway in the thickness direction.

[0109] Furthermore, when projected in the thickness direction, the mark 4 is spaced outward in the adjacent direction from the plurality of wirings 7. In other words, when projected in the thickness direction, the mark 4 does not overlap with the plurality of wirings 7, but is shifted from the plurality of wirings 7. The minimum distance L between the mark 4 and the wirings 7 has a lower limit of, for example, 10 μm, or preferably 50 μm, and an upper limit of, for example, 10 mm, or preferably 5 mm, or more preferably 3 mm.

[0110] The dimensions of the mark 4 are not particularly limited. The lower limit of the length of the mark 4 in the direction in which the wiring 7 extends is, for example, 10 μm, or preferably 50 μm, and the upper limit is, for example, 5 mm, or preferably 1 mm. The lower limit of the length of the mark 4 in the direction in which the multiple wirings 7 are adjacent to each other is, for example, 10 μm, or preferably 50 μm, and the upper limit is, for example, 5 mm, or preferably 1 mm.

[0111] The lower limit of the depth of the mark 4 is, for example, 1 μm, or preferably 5 μm, and the upper limit is 1 mm. The lower limit of the ratio of the depth of the mark 4 to the thickness (depth) of the mark layer 3 is, for example, 0.01, or preferably 0.1, and the upper limit is, for example, 0.9, or preferably 0.7.

[0112] As a result, the mark-formable layer 15 becomes the mark layer 3 on which the marks 4 are formed. As a result, a laminated sheet 1 with marks, which includes the inductor 2, the mark layer 3, and the marks 4, is obtained.

[0113] As shown in FIGS. 1C and 2D, thereafter, for example, vias 16 are formed in the marked laminate sheet 1.

[0114] In forming the vias 16, for example, the marks 4 are used as alignment marks to align the marked laminated sheet 1. For example, the mark 4 is used as a reference to adjust the position of the marked laminated sheet 1 in the plane direction relative to the device that will perform the next processing.

[0115] The method for forming the vias 16 is not particularly limited, and examples thereof include contact-type opening using a drill and non-contact processing using a laser.

[0116] For example, when projected in the direction in which the wirings 7 are adjacent, the via 16 overlaps with the mark 4, and also overlaps with the wiring 7 in a planar view. Specifically, the via 16 exposes the center of one surface of the wiring 7 in the thickness direction, and is a through-hole that penetrates the magnetic layer 8 and the mark layer 3 located on one side of the wiring 7 in the thickness direction in the thickness direction. The via 16 has a substantially circular shape in a planar view (not shown). Furthermore, the via 16 has a tapered shape in a cross-sectional view, with the opening area increasing toward one side in the thickness direction.

[0117] Thereafter, the marked laminate sheet 1 with the vias 16 formed therein undergoes processes such as photolithography and plating (copper plating, etc.) to form a conductive layer (not shown) on the wiring 7 exposed from the vias 16, and is then mounted on and bonded to an electronic device or electronic component. The electronic device or electronic component is electrically connected to the wiring 7 through the vias 16.

[0118] <Effects of one embodiment> The laminated sheet 13 includes a mark-formable layer 15. Therefore, if marks 4 are formed on the mark-formable layer 15, the laminated sheet 1 with marks can be aligned based on the marks 4, and vias 16 can be formed.

[0119] Furthermore, in this laminate sheet 13, if the material of the mark-formable layer 15 is a resin composition, the mark 4 can be easily formed.

[0120] Furthermore, this laminate sheet 13 satisfies at least one of the tests (a) to (e), for example, and therefore has excellent stability against processing using chemical solutions.

[0121] <Modification> In the following modifications, the same components and steps as those in the above-described embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted. Furthermore, each modification can achieve the same effects as those in the above-described embodiment unless otherwise specified. Furthermore, the embodiment and its modifications can be combined as appropriate.

[0122] The shape of the mark 4 is not limited to the above. Although not shown, examples of the shape of the mark 4 in plan view include a substantially V-shape, a substantially L-shape, a substantially X-shape, a substantially L-shape, a substantially I-shape (including a substantially linear shape), a substantially U-shape, a substantially C-shape, a substantially ring-shape (including a substantially elliptical ring-shape), a substantially circular shape (including a substantially elliptical shape), a substantially polygonal frame shape (including a substantially triangular frame shape and a substantially rectangular frame shape), and a substantially polygonal shape (including a substantially triangular shape and a substantially rectangular shape).

[0123] The position of the mark 4 is not particularly limited, and may be, for example, between adjacent wirings 7, although not shown.

[0124] As shown in FIG. 3, the markable layer 15 may be a laser-colorable layer and / or an ink-receptive layer.

[0125] When the mark-formable layer 15 is a laser-color-changeable layer, the laser-color-changeable layer contains, for example, a thermosetting resin as the resin and spherical carbon black as the first particles, and has, for example, a black color. When the laser-color-changeable layer is irradiated with a laser, the first particles (carbon black) in the irradiated area are thermally decomposed and removed, and the blackness of that area decreases (the color becomes lighter) (the area changes color). As a result, the mark-formable layer 15 becomes a mark layer 3 having a color-changed mark 4.

[0126] When the mark-formable layer 15 is an ink-receiving layer, the ink-receiving layer contains, for example, a hydrophilic polymer as a resin and spherical silica as a first particle. Ink (not shown) is printed onto the ink-receiving layer, and then the hydrophilic polymer and silica of the ink-receiving layer absorb (have affinity for) the ink. As a result, the mark-formable layer 15 becomes the mark layer 3 having the colored marks 4.

[0127] As shown in FIG. 4, the marks 4 may extend through the markable layer 15 .

[0128] 5, the marks 4 may be disposed on one surface in the thickness direction of the mark-formable layer 15. The marks 4 are made of, for example, a solid ink (preferably a cured product such as an ultraviolet cured product).

[0129] 6, the mark 4 is formed by cutting out a corner 6 (see FIG. 6) of the mark-formable layer 15. The mark 4 is formed by cutting out the corner 6 in a rectangular shape in the thickness direction.

[0130] 7, the mark 4 may include information about the laminate sheet 13 as a product, instead of or in addition to the alignment mark. Examples of the information include the lot number of the laminate sheet 13, the magnetic permeability of the laminate sheet 13, etc.

[0131] In a modification shown by the dashed-dotted line in Fig. 2B, mark-formable layers 15 are disposed on one surface 9 and the other surface 10 of inductor 2. In this modification, marks 4 are formed on each of the two mark-formable layers 15, as shown in Fig. 2C.

[0132] A conductive layer (not shown) can be formed in the vias 16. Examples of materials for the conductive layer (not shown) include a conductive material such as copper. For example, an electrolytic copper plating solution is used to form the conductive layer. This results in a marked laminate sheet 1 having a conductive layer (not shown). [Explanation of symbols]

[0133] 2 inductors 7 Wiring 8 Magnetic layer 13 Laminated Sheet 15 Mark-forming layer

Claims

1. a sheet-like inductor including a plurality of wirings and a magnetic layer in which the plurality of wirings are embedded; a mark-formable layer disposed on one surface of the inductor in a thickness direction; Equipped with the wiring includes a conductor wire and an insulating film covering the entire outer circumferential surface of the conductor wire; the inner circumferential surface of the magnetic layer is in contact with the entire outer circumferential surface of the wiring; The lower limit of the distance between adjacent wirings is 50 μm. the lower limit of the thickness of the mark-formable layer is 10 μm; A laminated sheet, characterized in that the mark-formable layer is not disposed on an end surface in a direction in which the wirings are adjacent to each other, which is perpendicular to the thickness direction of the inductor.

2. 2. The laminate sheet according to claim 1, wherein the mark-formable layer is made of a resin composition.

3. the resin composition is a thermosetting resin composition, 3. The laminate sheet according to claim 2, which satisfies at least one of the following tests (a) to (e): Test (a): The laminate sheet is cut into a 3 cm square to prepare a sample, and its relative permeability μ1 at a frequency of 10 MHz is measured. The sample is then immersed in 200 mL of a copper sulfate plating solution containing 66 g / L of copper sulfate pentahydrate, 180 g / L of sulfuric acid, 50 ppm of chlorine, and top lutina α at 25°C for 120 minutes, and the relative permeability μ2 of the sample at a frequency of 10 MHz is then measured. The rate of change in permeability before and after immersion is calculated using the following formula. As a result, the rate of change in the sample's permeability is 5% or less. Permeability change rate (%) = |μ1 - μ2| / μ1 x 100 Test (b): The laminated sheet is cut into a 3 cm square to prepare a sample, and its relative permeability μ3 at a frequency of 10 MHz is measured. The sample is then immersed in 200 mL of an acid-activated aqueous solution containing 55 g / L of sulfuric acid at 25°C for 1 minute, and the relative permeability μ4 of the sample at a frequency of 10 MHz is then measured. The rate of change in permeability before and after immersion is calculated using the following formula. As a result, the rate of change in the sample's permeability is 5% or less. Permeability change rate (%) = |μ3 - μ4| / μ3 × 100 Test (c): The laminated sheet is cut into a 3 cm square to prepare a sample, and its relative permeability μ5 at a frequency of 10 MHz is measured. The sample is then immersed in 200 mL of Reduction Solution Securigant P manufactured by Atotech Japan at 45°C for 5 minutes, and the relative permeability μ6 of the sample at a frequency of 10 MHz is then measured. The rate of change in permeability before and after immersion is calculated using the following formula. As a result, the rate of change in permeability of the sample is 5% or less. Permeability change rate (%) = |μ5 - μ6| / μ5 x 100 Test (d): The laminated sheet is cut into a 3 cm square to prepare a sample, and its relative permeability μ7 at a frequency of 10 MHz is measured. The sample is then immersed in 200 mL of Concentrate Compact CP manufactured by Atotech Japan at 80°C for 15 minutes, and the relative permeability μ8 of the sample at a frequency of 10 MHz is then measured. The rate of change in permeability before and after immersion is calculated using the following formula. As a result, the rate of change in the permeability of the sample is 5% or less. Permeability change rate (%) = |μ7 - μ8| / μ7 × 100 Test (e): The laminated sheet is cut into a 3 cm square to prepare a sample, and its relative permeability μ9 at a frequency of 10 MHz is measured. The sample is then immersed in 200 mL of Swelling Dip Securigant P (manufactured by Atotech Japan) at 60°C for 5 minutes. Then, the relative magnetic permeability μ10 of the sample at a frequency of 10 MHz is calculated. The rate of change in magnetic permeability before and after immersion is calculated using the following formula. As a result, the rate of change in magnetic permeability of the sample is 5% or less. Permeability change rate (%) = |μ9 - μ10| / μ9 × 100

Images