Laminated structure and method for manufacturing laminated structure

Abstract

In a laminated structure in which metal foils and insulating layers are alternately laminated, short-circuiting between adjacent metal foils across the insulating layers is suppressed. A laminated structure (10) according to one embodiment of the present invention has a structure in which a laminated body (20) is laminated in two or more layers. The laminated body (20) comprises a metal foil (22) and an insulating layer (24) laminated on one main surface of the metal foil (22). In the laminated structure (10), the metal foils (22) and the insulating layers (24) are laminated alternately. When adjacent laminated bodies (20) constituting the laminated structure (10) are set as a laminated body (20A) and a laminated body (20B) in this order from the lower part to the upper part, and the laminated body (20A) has an insulating layer (24a) located at the lower part and a metal foil (22a) located at the upper part, and the laminated body (20B) has an insulating layer (24b) located at the lower part and a metal foil (22b) located at the upper part, a notch is formed in at least one end of the laminated body (20A).

Description

Technical Field

[0001] The present invention relates to a stacked structure and a method for manufacturing the stacked structure. Background Art

[0002] As electronic components, laminated structures in which metal foils and insulating layers are alternately laminated are known. Examples of such laminated structures include laminated coils used in noise filters such as low-pass filters and high-pass filters (see Patent Document 1).

[0003] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Laid-Open No. 06-231938 Summary of the Invention Problems to be solved by the invention In the laminated coil as disclosed in Patent Document 1, there is a problem in that a short circuit is likely to occur between adjacent metal foils with an insulating layer interposed therebetween.

[0004] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a technology capable of suppressing short circuits between adjacent metal foils with insulating layers interposed therebetween in a laminated structure in which metal foils and insulating layers are alternately laminated.

[0005] Means used to solve problems One embodiment of the present invention is a laminated structure. The laminated structure is a laminated structure comprising two or more laminated layers, the laminated structure comprising a metal foil and an insulating layer laminated on one main surface of the metal foil, wherein the metal foils and insulating layers are laminated alternately, and when adjacent laminated layers constituting the laminated structure are sequentially designated as laminate A and laminate B from bottom to top, with laminate A comprising an insulating layer a at the bottom and a metal foil a at the top, and laminate B comprising an insulating layer b at the bottom and a metal foil b at the top, a notch is formed at at least one end of laminate A.

[0006] In the stacked structure of the embodiment described above, the ratio of the horizontal length of the horizontal end region of the cutout to the vertical length of the vertical end region, that is, the length ratio, may be 0.4 to 10.

[0007] The horizontal length of the horizontal end region may be 1 μm to 200 μm, and the vertical length of the vertical end region may be 1 μm to 400 μm.

[0008] The cutouts may be formed only in the metal foil a.

[0009] The cutouts may be formed in the metal foil a and the insulating layer a.

[0010] The stacked body may be in a rectangular shape.

[0011] The laminated structure may be in the form of a coil in which the laminated body is wound.

[0012] The multilayer structure of the above embodiment can be used for a noise filter.

[0013] Another embodiment of the present invention is a method for producing a laminated structure. The method comprises: a laminate sheet production step of laminating an insulating layer on one main surface of a metal foil to produce a laminate sheet; a laminate body production step of cutting the laminate sheet using a cutter having a blade angle of 20° to 60° to produce a laminate having cuts formed at the cut ends of the laminate sheet; and a laminate body production step of laminating the laminate body in a manner that alternates metal foils and insulating layers to produce the laminate structure.

[0014] In the method for producing a stacked structure of the embodiment described above, the stacked structure may be in a rectangular shape, and in the stacked structure production step, the stacked structure may be stacked while being wound.

[0015] Effects of the Invention According to the present invention, in a laminated structure in which metal foils and insulating layers are alternately laminated, short circuits between adjacent metal foils with the insulating layers interposed therebetween can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic cross-sectional view showing a schematic structure of a stacked structure according to an embodiment.

[0017] Figure 2 It is a partial cross-sectional view of the stacked structure according to the embodiment.

[0018] Figure 3 (a) and Figure 3 (b) in FIG. 1 is a plan view and a perspective view of a stacked body in one embodiment of the stacked structure, respectively.

[0019] Figure 4 This is a schematic diagram of a case where the stacked structure according to the embodiment has a coil-shaped structure.

[0020] Figure 5 This is a schematic cross-sectional view of a dicing blade used in the laminate production process.

[0021] Figure 6 (a)~ Figure 6 (d) is a schematic process diagram showing the steps of producing a laminate.

[0022] Figure 7 (a)~ Figure 7(d) is a schematic process diagram showing the steps of producing the stacked structure. DETAILED DESCRIPTION

[0023] Hereinafter, embodiments of the present invention will be described in detail. In addition, in this specification, the expression "a to b" in the description of a numerical range means a or more and b or less unless otherwise specified.

[0024] (Laminated structure) Figure 1 It is a schematic cross-sectional view showing a schematic structure of a stacked structure 10 according to the embodiment. Figure 2 It is a partial cross-sectional view of the stacked structure 10 according to the embodiment.

[0025] The laminated structure 10 is formed by laminating two or more laminated bodies 20. Each of the laminated bodies 20 constituting the laminated structure 10 includes a metal foil 22 and an insulating layer 24.

[0026] The materials constituting each stacked body 20 may be different in each stacked body 20 , but are preferably the same material from the viewpoint of properties and cost.

[0027] In this embodiment, metal foils 22 and insulating layers 24 are alternately stacked in the stacked structure 10. Although not shown, an adhesive layer may be provided as a component of the insulating layers 24 to ensure sufficient adhesion between the metal foils 22 and the insulating layers 24. The adhesive layer may be a component of all or part of the insulating layers 24 in the stacked structure 10.

[0028] In addition, Figure 1 In the following description, for ease of understanding, two stacked structures 20 adjacent to each other in a direction perpendicular to the main surface of the stacked structure 10 (hereinafter sometimes referred to as the "main surface perpendicular direction") are conveniently distinguished as stacked structure 20A and stacked structure 20B. Furthermore, the constituent components of stacked structure 24A are metal foil 22a and insulating layer 24a. Furthermore, the constituent components of stacked structure 24B are metal foil 22b and insulating layer 24b.

[0029] These reference numerals are described in Figure 2 Also applicable in.

[0030] In other words, two stacked bodies 20 adjacent to each other in the vertical direction within the stacked structure 10 are referred to as stacked body 20A and stacked body 20B, from the lower portion to the upper portion in the direction perpendicular to the main surface. Stacked body 20A includes an insulating layer 24a located at the lower portion in the direction perpendicular to the main surface and a metal foil 22a located at the upper portion in the direction perpendicular to the main surface. Stacked body 20B includes an insulating layer 24b located at the lower portion in the direction perpendicular to the main surface and a metal foil 22b located at the upper portion in the direction perpendicular to the main surface.

[0031] (metal foil) Examples of the material of the metal foil 22 include copper, aluminum, stainless steel, nickel, titanium, zinc, tin, gold, silver, platinum, and alloys thereof. When copper is used as the material of the metal foil 22 , it is preferably in the form of rolled copper foil having excellent bendability.

[0032] The thickness of the metal foil 22 is preferably 1 μm to 200 μm, more preferably 1 μm to 100 μm, and even more preferably 10 μm to 80 μm, from the viewpoint of workability.

[0033] (Insulation layer) The insulating layer 24 has at least an insulating main member, and an adhesive layer can be provided as a structural member on one or both main surfaces of the insulating main member.

[0034] The material of the insulating main component is preferably a material with excellent insulation and good processability. In addition to resins such as polyimide resin, epoxy resin, benzocyclobutene resin, fluororesin, glass composed of SiO2, glass fiber cloth, glass ceramics or mixtures of these materials, Ni-Zn ferrite can also be used. In this embodiment, polyimide resin is preferably used from the perspective of processability.

[0035] When polyimide resin or the like is used as the main insulating member, the insulating layer may absorb water, which may reduce the reliability of the laminated structure 10. Therefore, a moisture barrier (such as resin or wax) may be impregnated into the polyimide resin or the like.

[0036] The thickness of the insulating layer 24 is preferably 1 μm to 200 μm, more preferably 1 μm to 100 μm, and even more preferably 1 μm to 50 μm, from the viewpoint of ensuring insulation between two adjacent metal foils 22 with the insulating layer 24 interposed therebetween in the laminated structure 10 and workability.

[0037] As described above, an adhesive layer can be provided as a structural member of the insulating layer 24. The adhesive layer can be provided on one main surface or both main surfaces of the insulating main member.

[0038] The material of the adhesive layer is not particularly limited as long as it has sufficient adhesive strength to the insulating main member and the metal foil 22 , and examples thereof include acrylic adhesives, polyurethane adhesives, and epoxy adhesives.

[0039] The thickness of the adhesive layer is preferably 1 μm to 200 μm, more preferably 1 μm to 100 μm, and even more preferably 1 μm to 50 μm, from the viewpoints of workability and prevention of overflow of the adhesive layer.

[0040] The adhesive layer can be formed, for example, by applying a predetermined amount of an adhesive composition on one main surface or both main surfaces of the insulating layer main member and then drying the composition.

[0041] like Figure 2 As shown, at least one end portion of the metal foil 22a of the laminate 20A is provided with a notch (at Figure 2 In the example shown, a triangular region S with points E, F, and G as vertices). Due to this cutout, the metal foil 22a does not contact the horizontal end region ( Figure 2 R1) contact shown.

[0042] In the present embodiment, two stacked bodies 20A and 20B adjacent to each other in the vertical direction perpendicular to the main surface (stacking direction) in the stacked structure 10 have a structure in which the metal foil 22 a of the lower stacked body 20A in the vertical direction perpendicular to the main surface has at least a cutout.

[0043] In other words, the horizontal end region R1 is parallel to the main surface of each insulating layer 24a and 24b constituting the stacked structure 10 (horizontal direction), and extends from the exposed outermost portion ( Figure 2 Point E) to the innermost exposed portion of the insulating layer 24b ( Figure 2 Point G shown is also called the area of ​​the innermost part of the incision).

[0044] From the viewpoint of achieving sufficient end strength of the stacked structure 10 , the horizontal length H of the horizontal end region is preferably 1 μm to 200 μm, more preferably 1 μm to 150 μm, and even more preferably 1 μm to 100 μm.

[0045] exist Figure 2 In the example shown, the cut is in the tapered region of the end surface of the metal foil 22a and the line connecting point F to point G is a straight line. However, the line connecting point F to point G is not particularly limited and may be curved, bent, or a combination thereof.

[0046] In addition, the cut may be made not only in the metal foil 22 of the laminate 20 but also in a part of the insulating layer 24. In this case, for example, if Figure 2 The reference numerals of Figure 2 The end point F having the starting point G shown exists in the insulating layer 24a.

[0047] At this time, a notch is formed in the metal foil 22a and the insulating layer 24a at one end portion common to the laminate 20A. This notch prevents the metal foil 22a from contacting the horizontal end region R1 of the main surface of the laminate 20B on the insulating layer 24b side.

[0048] Therefore, in this embodiment, the two stacked bodies 20A and 20B adjacent to each other in the direction perpendicular to the main surface within the stacked structure 10 are configured such that at least the metal foil 22a of the stacked body 20A located at the lower position in the direction perpendicular to the main surface has a cutout. Furthermore, the insulating layer 24a of the stacked body 20A may also have a cutout. There is no particular limitation on whether the insulating layer 24 of the stacked bodies 20 has a cutout. The insulating layer 24 of each stacked body 20 within the stacked structure 10 may have a cutout, the insulating layer 24 of each stacked body 20 may have a cutout, or the insulating layer 24 of each stacked body 20 may not have a cutout.

[0049] like Figure 2 As shown, from the viewpoint of sufficiently obtaining the end strength of the stacked structure 10, the vertical direction end region ( Figure 2 The length V of R2) shown in FIG1 is preferably 1 μm to 400 μm, more preferably 1 μm to 300 μm, further preferably 1 μm to 200 μm, and particularly preferably 1 μm to 100 μm. The vertical end region is defined as the region from the exposed outermost portion of the insulating layer 24 b of the upper laminate 20B in the vertical direction of the main surface to the outermost portion of the cutout of the metal foil 22 a or the insulating layer 24 a of the lower laminate 20A in the vertical direction of the main surface in the stacking direction (vertical direction) of the two laminates 20A and 20B adjacent to each other in the vertical direction of the main surface in the stacking structure 10 ( Figure 2 In the example shown, the cut is at point F on the metal foil 22 a . However, when the cut is formed in the metal foil 22 a and the insulating layer 24 a of the laminate 20A described above, the outermost portion of the cut is located in the region of the insulating layer 24 a .

[0050] Here, in this embodiment, the ratio of the horizontal length H of the horizontal end region R2 to the vertical length V of the vertical end region, that is, the length ratio (hereinafter sometimes referred to as H / V) is preferably 0.4 to 10, and more preferably 0.4 to 5.

[0051] The above-described length ratio (H / V) can suppress electrical short circuits between two stacked bodies 20 adjacent to each other vertically in the main surface direction within the stacked structure 10 .

[0052] The stacked structure 10 of the present embodiment has the above-mentioned cutouts. However, when the stacked structure 10 has a plurality of cutouts, the shapes of the cutouts may be the same as or different from each other.

[0053] Furthermore, in the stacked structure 10 of this embodiment, in the stacked structures 10, which are vertically adjacent to each other in the direction perpendicular to the main surface, the outermost portion of the cutout of the metal foil 22a or the insulating layer 24a of the lower stacked structure 20A in the direction perpendicular to the main surface substantially does not form a shape protruding toward the upper stacked structure 20B in the direction perpendicular to the main surface, known as a burr. This further suppresses the occurrence of an electrical short circuit between the two stacked structures 20A and 20B vertically adjacent to each other in the direction perpendicular to the main surface within the stacked structure 10.

[0054] Figure 3 (a) and Figure 3 (b) in FIG. 1 is a plan view of a stacked body 20 and a perspective view of a stacked body 20 of one embodiment of the stacked structure 10. Figure 3 (a) and Figure 3 As shown in (b) in FIG. 1 , in one embodiment of the stacked structure 10 , the stacked structure 20 has a rectangular shape when viewed from above, with a pair of opposing sides being long sides. Figure 3 In (b), a side surface of the long side is formed Figure 1 and Figure 2 The incision shown (not shown).

[0055] The stacked structure 10 may be a structure in which a plurality of separate stacked bodies 20 are stacked, or may be a coil-shaped structure in which a rectangular stacked body 20 is wound. Figure 4 This is a schematic diagram of a case where the stacked structure of the embodiment is a coil-shaped structure, and the cutout is omitted for ease of understanding. Figure 4 A portion of the cross section taken along line AA' is shown. Figure 1 The stacked structure shown.

[0056] (Method for Manufacturing Laminated Structure) One method of manufacturing a stacked structure according to the present embodiment includes: a stacking sheet manufacturing step of stacking an insulating layer on a main surface of one side of a metal foil to manufacture a stacked sheet; a stacking body manufacturing step of cutting the stacked sheet using a cutting knife having a blade tip angle to manufacture a stacked body having an incision formed at the cut end of the stacked sheet; and a stacking structure manufacturing step of stacking the stacked body in a manner that alternates metal foil and insulating layers to manufacture a stacked structure.

[0057] Hereinafter, the method for producing the laminated structure of the present embodiment, namely, the laminated sheet production step, the laminated body production step, and the laminated structure production step will be described in detail.

[0058] (Laminated sheet production process) The laminate sheet production step is a step of producing a laminate sheet by laminating an insulating layer on one main surface of a metal foil.

[0059] The lamination method of laminating an insulating layer on one main surface of a metal foil can be divided into two types: a method of directly producing an insulating main member and a lamination method using an adhesive layer as an insulating layer structural member.

[0060] In addition to the method of directly manufacturing the insulating main component by applying a coating as the insulating main component (insulating layer) on the main surface of one side of the metal foil using an existing coating machine and drying it, a method of directly laminating a film or sheet-like insulating main component on the main surface of one side of the metal foil using an existing laminating machine can also be applied.

[0061] The following describes a method for laminating a structural member using an insulating layer, that is, an adhesive layer.

[0062] First, an insulating main component is prepared. In addition to forming the insulating main component by applying a coating material serving as the insulating main component to the releasable main surface of the substrate using a conventional coating machine and drying the coating, a method using a film or sheet-like insulating layer can also be applied.

[0063] Next, an adhesive composition is applied to one or both main surfaces of the insulating main component using a conventional coating machine and dried to form an adhesive layer. Subsequently, a method of laminating the adhesive layer-side main surface of the insulating layer to one main surface of the metal foil using a conventional laminator can be applied.

[0064] The shape of the laminated sheet obtained in the laminated sheet production step is not particularly limited and may be rectangular.

[0065] (Laminate production process) The laminate production step is a step of cutting the laminate sheet using a cutter blade having a blade edge angle to produce a laminate with cut edges of the laminate sheet having cuts formed therein.

[0066] Figure 5 1 is a schematic cross-sectional view of a cutter blade 50 used in a laminate production process. One main surface of the cutter blade 50 is a non-edge surface 52 , and the other main surface of the cutter blade 50 is a edge surface 54 .

[0067] The blade tip angle θ of the dicing blade 50 is an angle that minimizes the generation of burrs and cuts at the ends of the metal foil or insulation layer when cutting the laminated sheet. It is preferably between 20° and 60°, more preferably between 25° and 55°, and even more preferably between 30° and 50°. If the blade tip angle θ is greater than 60°, the dicing blade 50 will have difficulty penetrating the laminated sheet, resulting in poor cutting performance. If the blade tip angle θ is less than 20°, the dicing blade 50 may not only be damaged but also be prone to burrs.

[0068] In addition, the cutting blade is not particularly limited and may be a rotary blade or a fixed blade.

[0069] By changing the blade tip angle θ, the shape of the cut can be adjusted. For example, Figure 2 The horizontal length H of the horizontal end region R1 of the slit S is shown, and the vertical length V of the vertical end region R2 is shown. Regarding the length ratio (H / V), as the blade tip angle θ of the cutting blade 50 decreases, the length H tends to decrease and the length V tends to increase, so the length ratio (H / V) decreases. As the blade tip angle θ increases, the length H tends to increase and the length V tends to decrease, so the length ratio (H / V) increases.

[0070] Figure 6 (a)~ Figure 6 (d) is a schematic process diagram illustrating the laminate production process. While this diagram illustrates an example of simultaneous cutting using two cutting blades to facilitate understanding of the process, there is no limit to the number of cutting blades used, and cutting can be performed simultaneously at multiple locations, sequentially at different locations, or using a single cutting blade to cut the laminate 40 at multiple locations.

[0071] First, if Figure 6 As shown in (a) of FIG. 1 , a laminated sheet 40 having a structure in which an insulating layer 24 is laminated on a metal foil 22, produced in the laminated sheet production step, is fixed to a table or the like. The fixing method is not particularly limited, and the laminated sheet 40 is fixed so that the main surface of the metal foil 22 faces the contact side of the dicing blade.

[0072] Then, if Figure 6 As shown in (b) in the figure, the cutting blades 50 (cutting blades 50a, 50b) are placed above the laminated sheet 40. Specifically, the cutting blades 50 are positioned with respect to the flat surface 52 so that the edged surfaces 54 (edged surfaces 54a, 54b) of the cutting blades 50 face the cut surface of the laminated sheet on the side that will become the laminated body, and the leading end of the blade tip extending from the flat surface 52 (edged surfaces 52a, 52b) is located at the outermost portion of the desired cutout of the laminated body.

[0073] Then, if Figure 6 As shown in (c), a pair of cutting blades 50 (cutting blade 50a and cutting blade 50b) are pressed into the main surface of the metal foil 22 of the laminate 40 in the vertical direction to cut the metal foil 22 and then cut the insulating layer 24. Figure 6 As shown in (d), a laminate 20 having cuts of a predetermined width is obtained.

[0074] In addition, when using a cutting knife to cut the laminated sheet 40 at multiple locations, it is sufficient to repeatedly position the cutting knife 50 by using the bladeless surface 52 as a reference to set the cutting knife 50 so that the front end of the blade tip continuous from the bladeless surface 52 becomes the outermost part of the desired incision.

[0075] The shape of the laminate 20 obtained in the laminate production step is not particularly limited, and can be, for example Figure 3 That kind of rectangle.

[0076] Laminated structure production process The laminated structure production step is a step of producing a laminated structure by laminating laminates so that metal foils and insulating layers are alternately stacked.

[0077] Figure 7 (a)~ Figure 7 (d) is a schematic process diagram showing the steps of producing the stacked structure.

[0078] like Figure 7 As shown in (a) of FIG. 1 , by stacking two laminates 20 obtained in the laminate production step in a manner that metal foils 22 and insulating layers 24 are alternately stacked, a laminate structure 10 in which two laminates 20 are stacked can be obtained (see FIG. 1 ). Figure 7 (b) in the figure).

[0079] Furthermore, if Figure 7 As shown in (c) of FIG. 1 , the third laminate 20 is laminated in such a manner that the metal foil 22 and the insulating layer 24 are alternately laminated. Figure 7 The stacked structure 10 shown in (b) can be obtained by stacking three stacked structures 20 (see Figure 7 (d) in the figure).

[0080] By repeating such stacking a desired number of times, it is possible to obtain the stacked structure 10 in which a desired number of stacked layers 20 are stacked.

[0081] The lamination method is not particularly limited, and examples thereof include a "lamination method using an adhesive layer" and a "winding lamination method."

[0082] There are two types of lamination methods using an adhesive layer.

[0083] The first method is to obtain the laminated structure 10 by directly attaching the adhesive layer, which is a component of the insulating layer 24, or laminating the adhesive layer, which is a component of the insulating layer 24, using an existing laminator or the like, and alternately laminating the metal foil 22 and the insulating layer 24.

[0084] The second method is a method applicable to the case where the insulating layer 24 does not have an exposed adhesive layer.

[0085] First, an adhesive composition made of the same material as the adhesive layer, which is a structural member of the insulating layer 24, is applied to either the main surface of the metal foil 22 of the laminate 20 or the main surface of the insulating main member where the insulating layer is exposed using an existing coater, and dried to form a laminating adhesive layer.

[0086] Next, the metal foils 22 and the insulating layers 24 are alternately laminated by directly attaching the laminating adhesive layer or laminating the laminating adhesive layer using a conventional laminator, thereby obtaining the laminated structure 10 .

[0087] The winding lamination method is suitable when the laminated body 20 is rectangular.

[0088] The rectangular laminate 20 obtained in the laminate production process is wound and stacked to obtain Figure 4 The method of forming the coil-shaped laminated structure 10 is shown.

[0089] The cross section perpendicular to the main surface of the laminated structure 10 obtained by the lamination method using the adhesive layer and the cross section along the main surface of the laminated structure 10 obtained by the roll-to-roll lamination method are shown in FIG. Figure 4 A portion of the cross section taken along line AA' shown has Figure 1 The stacked structure shown.

[0090] In the stacked structure 10 obtained by the roll-to-roll lamination method, the metal foils 22 and the insulating layer 24 included in the stacked body 20 constituting the stacked structure 10 are physically continuous, and the metal foils 22 are electrically connected to each other.

[0091] [Example] Next, embodiments of the present invention will be described in further detail based on specific examples.

[0092] (Fabrication of adhesive layer) An acrylic adhesive coating was applied to the main surface of a release-treated PET film 1 and dried to a thickness of 2.5 μm. The coated main surface was then covered with a release-treated PET film 2 having a weaker release strength than the PET film 1, thereby forming an adhesive layer with double-sided PET film. The thickness of the adhesive layer was 2.5 μm.

[0093] (Production of insulation layer) The PET film 2 with the adhesive layer of the double-sided PET film was peeled off and then a 5 μm thick polyimide film (Kapton 20EN, manufactured by DuPont Toray) was laminated to obtain an insulating layer with a single-sided PET film having a structure of “PET film 1 / adhesive layer / polyimide film”.

[0094] (Production of laminated sheets A to D) The PET film 1 with the insulating layer of the single-sided PET film was peeled off, and four types of rolled copper foils of varying thickness were bonded to the exposed main surface of the adhesive layer. This yielded four types of laminated sheets A to D with a "rolled copper foil / adhesive layer / polyimide film" structure. The thickness of the rolled copper foil used is shown in Table 1.

[0095]

Table 1

[0096] (Production of Laminated Body) After cutting the produced laminated sheets A to D into a main surface of 50 mm × 50 mm, the rolled copper foil of each laminated sheet A to D was cut by pressing in from the vertical direction at two locations on the main surface using rotary knives (outer diameter 100 mm, SKH material) with seven different blade angles, thereby obtaining each laminated body having cuts at both ends of the metal foil on the cut surface of the laminated sheet on the side that becomes the laminate.

[0097] In this case, only one type of rotary blade is used to produce one laminate.

[0098] Furthermore, the width of the polyimide film in the cross section (the width in the direction parallel to the main surface of the laminate) was adjusted to 20 mm before cutting each laminate. Specifically, the rotary blade was positioned at two locations 15 mm from both ends of the width direction parallel to the main surface on one side of each laminate sheet A-D, with the non-main surface as the reference, so that the angled surface of the rotary blade was aligned with the cut surface of the laminate sheet that would become the laminate, and the tip of the blade, which continued from the non-angled surface, was positioned at the desired outermost portion of the cut of the laminate.

[0099] Furthermore, in order to form a stacked structure later, five stacked structures were produced.

[0100] For each of the produced laminates, the horizontal length H of the horizontal end region R1 and the vertical length V of the vertical end region R2 were measured using an optical microscope, and the length ratio (H / V) was calculated. The horizontal length H of the horizontal end region R1 and the vertical length V of the vertical end region R2, as well as the length ratio (H / V), were summarized for each laminate with respect to the blade edge angle and are shown in Tables 2 and 3, respectively.

[0101]

Table 2

[0102]

Table 3

[0103] Furthermore, among the obtained laminates, all the laminates obtained by cutting with a rotary blade having a blade edge angle of 10° had burrs generated on the cut surfaces.

[0104] Furthermore, in all the laminates obtained by cutting with a rotary blade having a blade edge angle of 70°, deformation of the cut shape was observed due to difficulty in the cutter blade entering the laminate sheet, and the desired cut shape was not formed.

[0105] (Fabrication of Laminated Structure) For each type of laminate produced, the following operation was repeated for five (referred to as laminates 1 to 5), namely, first, the structural component of laminate 2, i.e., the insulating layer, was directly laminated on the structural component of laminate 1, i.e., the metal foil. Then, the structural component of laminate 3, i.e., the insulating layer, was directly laminated on the structural component of the laminate 2, i.e., the metal foil. Thus, each laminate structure was produced by stacking five laminates.

[0106] Among the obtained stacked structures, in the stacked structures made using a rotating knife with a blade tip angle of 20°, 30°, 40°, 50° and 60°, since the five stacked body cut surfaces constituting each stacked structure have no burrs and have the desired cut shape, no short circuit problem caused by the cut surface shape between the metal foils adjacent to each other through the insulating layer was confirmed.

[0107] In contrast, in each stacked structure produced using a rotating blade with a blade tip angle of 10°, burrs were observed on the cut surfaces of the five stacked structures constituting each stacked structure, indicating a short circuit problem caused by the cut surface shape between adjacent metal foils separated by an insulating layer.

[0108] Furthermore, in each stacked structure produced using a rotating knife with a blade tip angle of 70°, deformation of the cut shapes of the five stacked bodies constituting each stacked structure was confirmed, thereby confirming a short circuit problem caused by the cut surface shape between adjacent metal foils separated by an insulating layer.

[0109] (Applications of Laminated Structures) The multilayer structure 10 of this embodiment is preferably used in electronic devices. In particular, the coil-shaped multilayer structure 10 can be used as a multilayer coil in noise filters such as low-pass filters and high-pass filters.

[0110] In recent years, laminated coils are required to be further thinned. By applying the laminated structure 10 of this embodiment, electrical short circuits can be suppressed, and the operational reliability of the noise filter can be improved.

[0111] As mentioned above, although embodiment of this invention was described, these are illustrations of this invention, and various structures other than the above-mentioned can also be adopted.

[0112] Description of Reference Numerals 10: Laminated structure, 20 (20A, 20B): laminated body, 22 (22a, 22b): Metal foil, 24 (24a, 24b): Insulation layer.

Claims

1. A laminated structure, wherein two or more layers are laminated, The laminate is composed of a metal foil and an insulating layer laminated on one main surface of the metal foil. In the laminated structure, the metal foils and the insulating layers are laminated alternately. When the adjacent stacks constituting the stacked structure are sequentially designated as stack A and stack B from bottom to top, and the stack A comprises an insulating layer a at the bottom and a metal foil a at the top, and the stack B comprises an insulating layer b at the bottom and a metal foil b at the top, A notch is formed at at least one end portion of the stacked body A.

2. The laminated structure according to claim 1, wherein The ratio of the horizontal length of the horizontal end region of the incision to the vertical length of the vertical end region, that is, the length ratio, is 0.4-10.

3. The laminated structure according to claim 2, wherein The horizontal length of the horizontal end region is 1 μm to 200 μm, and the vertical length of the vertical end region is 1 μm to 400 μm.

4. The laminated structure according to any one of claims 1 to 3, wherein The cutouts are formed only in the metal foil a.

5. The laminated structure according to any one of claims 1 to 3, wherein The cutouts are formed in the metal foil a and the insulating layer a.

6. The laminated structure according to any one of claims 1 to 3, wherein The stacked body has a rectangular shape.

7. The laminated structure according to claim 6, wherein The stacked structure is in a coil shape obtained by winding the stacked body.

8. The laminated structure according to claim 7, wherein The laminated structure is used for a noise filter.

9. A method for producing a laminated structure, wherein: have: a laminated sheet manufacturing step of laminating an insulating layer on one main surface of the metal foil to manufacture the laminated sheet; a laminate production step of cutting the laminate sheet using a cutter having a blade angle of 20° to 60° to produce a laminate with cut edges of the laminate sheet having cuts thereon; and The laminated structure manufacturing step manufactures a laminated structure by stacking the laminated bodies so that metal foils and insulating layers are alternately stacked.

10. The method for producing a laminated structure according to claim 9, wherein: The shape of the stacked body is rectangular, In the stacked structure production step, the stacked bodies are stacked while being wound.

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