Thin-film capacitors and electronic circuit boards incorporating them

Abstract

The present invention provides a thin-film capacitor with high adhesion to a circuit board. The thin-film capacitor (1) comprises: a metal foil (10) having a roughened upper surface (11); a dielectric film (D) covering the upper surface (11) of the metal foil (10) and having an opening that partially exposes the metal foil (10); a first electrode layer connected to the metal foil (10) via the opening; and a second electrode layer connected to the dielectric film (D) but not connected to the metal foil (10). The angle θa formed by another main surface (12) and the side surface (13) of the metal foil (10) is greater than 20° and less than 80°. Thus, the angle of the side surface (13) is a conical shape greater than 20° and less than 80°, thereby suppressing warping and improving adhesion to the multilayer substrate when embedded in the multilayer substrate.

Description

Technical Field

[0001] The present invention relates to thin film capacitors and electronic circuit boards having the same, and particularly to thin film capacitors using metal foil and electronic circuit boards having the same. Background Technology

[0002] In circuit boards housing ICs, decoupling capacitors are typically installed to stabilize the potential of the power supplied to the ICs. Multilayer ceramic chip capacitors are commonly used as decoupling capacitors, with multiple multilayer ceramic chip capacitors mounted on the surface of the circuit board to ensure the necessary decoupling capacitance.

[0003] In recent years, circuit boards have become miniaturized, sometimes resulting in insufficient space for mounting multiple stacked ceramic chip capacitors. Therefore, thin-film capacitors that can be embedded in the circuit board are sometimes used instead of stacked ceramic chip capacitors (see Patent Documents 1-4).

[0004] Patent Document 1 describes a thin-film capacitor with the following structure: a porous metal substrate is used, and an upper electrode is formed on its surface via a dielectric film. Patent Document 2 describes a thin-film capacitor with the following structure: a metal substrate with one main surface roughened is used, and an upper electrode is formed on the roughened surface via a dielectric film. Patent Documents 3 and 4 describe thin-film capacitors with the following structure: a conductive porous substrate is formed in the support portion, and an upper electrode is formed on the roughened surface via a dielectric film.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. WO2015-118901

[0008] Patent Document 2: International Publication No. WO2018-092722

[0009] Patent Document 3: International Publication No. WO2017-026247

[0010] Patent Document 4: International Publication No. WO2017-014020 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] However, the thin-film capacitor described in Patent Document 1 has a side electrode structure, resulting in a longer electrode line length, which leads to structural problems such as increased ESR (equivalent series resistance) and ESL (equivalent series inductance). Furthermore, because the thin-film capacitor described in Patent Document 1 uses a porous metal substrate, separating the lower electrode made of the metal substrate from the upper electrode covered by a dielectric film is difficult, leading to a tendency for short circuits. Additionally, the thin-film capacitor described in Patent Document 2 uses one main surface of the metal substrate as the upper electrode and the other as the lower electrode; to place a pair of terminal electrodes on the same surface, the electrodes need to be routed back via the side of the [0] element, resulting in a complex structure. Furthermore, the thin-film capacitors described in Patent Documents 3 and 4, by placing a pair of terminal electrodes on opposite sides of the metal substrate, cannot be accessed from a single side. Moreover, the use of a support increases the overall thickness.

[0013] Therefore, the object of the present invention is to provide an improved thin-film capacitor and an electronic circuit board having the same.

[0014] Technical solutions for solving the problem

[0015] The present invention provides a thin-film capacitor comprising: a metal foil having one main surface roughened; a dielectric film covering one main surface of the metal foil and having an opening that partially exposes the metal foil; a first electrode layer in contact with the metal foil via the opening; and a second electrode layer in contact with the dielectric film but not with the metal foil, wherein the metal foil has another main surface located opposite to one main surface and a side surface connecting the two main surfaces, and the angle formed by the other main surface and the side surface is greater than 20° and less than 80°.

[0016] This invention provides a method for manufacturing a thin-film capacitor, which involves roughening one main surface of a metal foil, forming a dielectric film on the roughened main surface of the metal foil, exposing a portion of the metal foil by removing a portion of the dielectric film, forming a first electrode layer in contact with a portion of the metal foil and a second electrode layer in contact with the dielectric film but not with a portion of the metal foil, and monolithically forming the metal foil with a conical side surface. The angle formed by another main surface and the side surface on the opposite side of one main surface of the metal foil is greater than 20° and less than 80°.

[0017] Invention Effects

[0018] According to the present invention, an opening is provided in a portion of the dielectric film, thus enabling a pair of terminal electrodes to be disposed on the same surface without using side electrodes or the like. Furthermore, the side angle is a conical shape exceeding 20° and less than 80°, thereby suppressing warping and improving adhesion to the multilayer substrate during embedding. Attached Figure Description

[0019] Figure 1A This is a general cross-sectional view illustrating the structure of a thin-film capacitor 1 according to an embodiment of the present invention. Figure 1B This is a rough top view of film capacitor 1.

[0020] Figure 1B This is a rough top view of film capacitor 1.

[0021] Figure 1C This is a rough cross-sectional view showing an example where the conductive component 32 is omitted from the film capacitor 1.

[0022] Figure 1D yes Figure 1C A general top view of the thin-film capacitor 1 shown.

[0023] Figure 2 This is a general cross-sectional view used to illustrate the shape of the side surface 13 of the film capacitor 1.

[0024] Figure 3 This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0025] Figure 4 This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0026] Figure 5A This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0027] Figure 5B This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0028] Figure 6 This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0029] Figure 7A This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0030] Figure 7B yes Figure 7A A rough top view.

[0031] Figure 8A This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0032] Figure 8B yes Figure 8A A rough top view.

[0033] Figure 9 This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0034] Figure 10 This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0035] Figure 11A This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0036] Figure 11B yes Figure 11A A rough top view.

[0037] Figure 12A This is a general cross-sectional view showing an example of the location where the insulating component 21 is formed.

[0038] Figure 12B This is a general cross-sectional view showing another example of the location where the insulating component 21 is formed.

[0039] Figure 13 This is a general cross-sectional view showing an example of the shape of the insulating component 21.

[0040] Figure 14A This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0041] Figure 14B yes Figure 14A A rough top view.

[0042] Figure 15A This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0043] Figure 15B yes Figure 15A A rough top view.

[0044] Figure 16A This is a schematic cross-sectional view showing the case where the crystal grain size of the metal foil 10 is relatively large.

[0045] Figure 16B yes Figure 16A A rough top view.

[0046] Figure 17A This is a schematic cross-sectional view showing the case where the crystal grain size of the metal foil 10 is small.

[0047] Figure 17B yes Figure 17A A rough top view.

[0048] Figure 18 This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0049] Figure 19 yes Figure 18 A rough top view.

[0050] Figure 20A This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0051] Figure 20B yes Figure 20A A rough top view.

[0052] Figure 21 This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0053] Figure 22A This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0054] Figure 22B yes Figure 22A A rough top view.

[0055] Figure 23A This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0056] Figure 23B yes Figure 23A A rough top view.

[0057] Figure 24A This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0058] Figure 24B yes Figure 24A A rough top view.

[0059] Figure 25A This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0060] Figure 25B yes Figure 25A A rough top view.

[0061] Figure 26A This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0062] Figure 26B yes Figure 26A A rough top view.

[0063] Figure 27 This is a process diagram illustrating the manufacturing method of film capacitor 1.

[0064] Figure 28 This is a general cross-sectional view of an electronic circuit board having a structure in which a thin-film capacitor 1 is embedded in a multilayer substrate 100.

[0065] Figure 29 This is a general cross-sectional view of an electronic circuit board having a structure in which a thin-film capacitor 1 is mounted on the surface of a multilayer substrate 300.

[0066] Figure 30 This is a table that represents the evaluation results of the samples. Detailed Implementation

[0067] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0068] Figure 1A This is a general cross-sectional view illustrating the structure of a thin-film capacitor 1 according to an embodiment of the present invention. Figure 1B This is a rough top view of film capacitor 1.

[0069] like Figure 1A and Figure 1B As shown, the film capacitor 1 includes: a metal foil 10; annular or polygonal annular insulating members 21 and 22 formed on the upper surface 11 of the metal foil 10; electrical members 31 and 32 formed on the upper surface 11 of the metal foil 10 and divided by the insulating members 21 and 22; a terminal electrode 51 connected to the conductive member 31 via a seed layer 40; and a terminal electrode 52 connected to the conductive member 32 via the seed layer 40. The metal foil 10 is made of a metal material such as aluminum, copper, chromium, nickel, or tantalum, and at least a portion of the main surfaces located on opposite sides, namely the upper surface 11 and the lower surface 12, is roughened. Aluminum is most preferably used as the material of the metal foil 10. A dielectric film D is formed on the upper surface 11 and the lower surface 12 of the metal foil 10. The insulating members 21 and 22 are made of resin, for example. The conductive members 31 and 32 are made of conductive polymer material, for example. The seed layer 40 and terminal electrodes 51 and 52 are, for example, made of copper, nickel or gold and their alloys or layer structures.

[0070] An annular or polygonal annular insulating member 21 is disposed within a slit that electrically separates the electrode layer composed of terminal electrode 51 and conductive member 31 from the electrode layer composed of terminal electrode 52 and conductive member 32. Terminal electrode 52 and conductive member 32 are located within a region surrounded by insulating member 21, and outside the region surrounded by insulating member 21, within a region surrounded by insulating member 22. Within the region surrounded by insulating member 21, part or all of the dielectric film D formed on the upper surface 11 of metal foil 10 is removed, forming an opening in the dielectric film D. Thus, terminal electrode 52 is electrically connected to metal foil 10 via conductive member 32. Alternatively, as... Figure 1C and Figure 1DAs shown, the conductive component 32 can also be omitted, and the metal foil 10 can be connected to the terminal electrode 52 directly or via the seed layer 40. Conversely, the dielectric film D formed on the upper surface 11 of the metal foil 10 is not removed outside the area surrounded by the insulating component 21. That is, the conductive component 31 is not in contact with the metal foil 10 but is in contact with the dielectric film D, and the terminal electrode 51 and the metal foil 10 are mutually insulated. Thus, the terminal electrodes 51 and 52 function as a pair of capacitive electrodes facing each other via the dielectric film D. Furthermore, the dielectric film D is formed on the roughened upper surface 11 of the metal foil 10, increasing the surface area of ​​the upper surface 11, thereby enabling a large capacitance.

[0071] On the outer side of the area surrounded by the insulating member 22, the dielectric film D disposed on the upper surface 11 of the metal foil 10 is exposed. Thus, the roughened surface is exposed at the outer periphery of the film capacitor 1, improving adhesion when embedded in the multilayer substrate. The side 13 connecting the upper surface 11 and the lower surface 12 of the metal foil 10 is not roughened, and its surface is covered by the insulating film 14. The insulating layer 14 not only ensures insulation between the conductor pattern embedded in the multilayer substrate and the metal foil 10, but also improves adhesion relative to the multilayer substrate. Here, an annular or polygonal annular insulating member 22 exists between the conductive member 31 and the side 13 of the metal foil 10, and a gap region without conductive members is provided on the outer side of the annular or polygonal annular insulating member 22. Therefore, even when the insulating film 14 is thin, short circuits between the conductive member 31 and the metal foil 10 are prevented.

[0072] Inorganic insulating materials and resin materials can be used as the material for insulating layer 14. Using resin materials can further improve adhesion to the multilayer substrate. Al₂O₃ and TiO₂ can be used as inorganic insulating materials. x Ta2O5, SiN x TiN, TaN, or laminates thereof. As a resin material, any of thermoplastic resins and thermosetting resins can be used. As a thermoplastic resin, polyester, polyimide, polyamide, polyamide-imide, polyethersulfone, polysulfone, polyetheretherketone, polystyrene, polyethylene, polypropylene, or laminates thereof can be used. As a thermosetting resin, three-dimensional cured materials such as epoxy resin, phenolic resin, polyurethane resin, melamine resin, and acrylic resin, or laminates thereof, can be used.

[0073] Regarding the grain size of the central portion (non-coarsened portion) of the metal foil 10, it is preferably less than 15 μm in the planar direction (parallel to the upper surface 11 and lower surface 12) and less than 5 μm in the thickness direction (perpendicular to the upper surface 11 and lower surface 12), and preferably the crystal orientation is aligned as much as possible in the planar direction. Accordingly, as described later, the positional accuracy of the side surface 13 can be improved.

[0074] The thin-film capacitor 1, by being embedded in a multilayer substrate, can be used as a decoupling capacitor. The thickness T of the thin-film capacitor 1 is very thin, preferably 200 μm or less, more preferably 100 μm or less, and particularly preferably 50 μm or less. Therefore, when the terminal electrode 51 and the conductive component 31 are formed on the upper surface 11 side, it is easy to form a shape that convexes towards the lower surface 12 side. The thinner the thickness T of the thin-film capacitor 1, the more pronounced this phenomenon becomes. Therefore, when mounting to suppress element warping during embedding in the multilayer substrate, Figure 2 In the cross-section shown, when a straight line L1 is defined along the upper surface 11, a straight line L2 along the lower surface 12, and a straight line L3 along the side surface 13, the angle θa formed by the straight lines L2 and L3 is preferably 20° < θa < 80°. That is, it is preferable that the area of ​​the lower surface 12 is wider than the area of ​​the upper surface 11. Accordingly, the area of ​​the side surface 13 is increased, improving the adhesion between the side surface 13 of the film capacitor 1 and the multilayer substrate, thus improving the strength and reliability of the film capacitor 1. As mentioned above, the thinner the thickness T, the more significant the warping of the film capacitor 1. Therefore, the thinner the thickness T of the film capacitor 1, the more significant the effect of designing the angle θa to be 20° < θa < 80°. In this case, it is more preferable to satisfy 40° ≤ θa ≤ 75°. In addition, the angle θa is preferably an angle at which the virtual straight line L3 extending along the side surface 13 does not interfere with the insulating member 22. By designing the angle θa within the aforementioned range, warping during the mounting of the film capacitor 1 is reduced, and the contact area between the side surface 13 and the insulating resin constituting the multilayer substrate is appropriately controlled. Therefore, the strength and reliability of the film capacitor 1 can be further improved. Furthermore, the side surface 13 of the film capacitor 1 can also have a curved shape where the angle θa is larger closer to the upper surface 11 and smaller closer to the lower surface 12. Thus, when the angle θa is not fixed, its value is defined by an average value.

[0075] Next, an example of a method for manufacturing the film capacitor 1 will be described.

[0076] First, prepare 10 metal foils (e.g., aluminum) with a thickness of approximately 50 μm. Figure 3 ), roughened by etching its upper surface 11 and lower surface 12 ( Figure 4Alternatively, the metal foil 10 can be formed by sintering metal powder, instead of roughening the flat metal foil 10. This forms a porous layer 11a on the upper surface 11 and a porous layer 12a on the lower surface 12 of the metal foil 10. Between the porous layers 11a and 12a is an unroughened non-porous layer 10a. In this case, roughening only the upper surface 11 is sufficient; roughening the lower surface 12 is not necessary. However, by roughening both surfaces, warping of the metal foil 10 can be prevented. Furthermore, for the upper surface 11, etching is preferably performed under conditions that maximize the surface area. Even when both the upper and lower surfaces 11 and 12 are roughened, the etching conditions for the upper and lower surfaces 11 can differ. For example, for the lower surface 12, etching can be performed under conditions that maximize adhesion to the multilayer substrate.

[0077] Next, a dielectric film D is formed on the surface of the metal foil 10. Figure 5A The dielectric film D can be formed by oxidizing the metal foil 10, or by film formation methods with excellent coverage such as ALD, CVD, and fog CVD. Al2O3, TiO2, Ta2O5, and SiN can be used as materials for the dielectric film D. x TiN x TaN x The material of the dielectric film D can also be amorphous. In this case, the composition ratio of the dielectric film D may not be the composition ratio described above. In this case, it is sufficient to form the dielectric film D at least on the upper surface 11; it is not necessary to form the dielectric film D on the lower surface 12. However, by also forming the dielectric film D on the lower surface 12, the insulation of the lower surface 12 can be ensured. Figure 5B As shown, the dielectric film D formed on the lower surface 12 can have the same composition as the dielectric film D formed on the upper surface 11, or it can be a barrier film E with a different composition, or it can be a stacked structure of dielectric film D and barrier film E. Furthermore, if a barrier film E is present on the lower surface 12 of the metal foil 10, the intrusion of reaction-generated gases produced by the resin constituting the multilayer substrate can be suppressed during the curing of the multilayer substrate. After forming the dielectric film D or the barrier film E, a transport substrate 60 is attached to the lower surface 12 of the metal foil 10. Figure 6 ).

[0078] Next, a photosensitive resist layer is formed on the upper surface 11 of the metal foil 10, and then exposed and developed to form a patterned resist layer 61. Figure 7A , 7B An opening 62 is provided on the resist layer 61 to expose the dielectric film D. The resist layer can be positive or negative.

[0079] Next, by using the resist layer 61 as a mask to remove part or all of the dielectric film D, the metal foil 10 is exposed at the opening 62. Figure 8A , 8B As a method for removing the dielectric film D, reverse sputtering, ion polishing, RIE, wet etching, etc., can be used. Furthermore, the upper surface 11 of the metal foil 10 is roughened in this stage; therefore, by using reverse sputtering, ion polishing, RIE, etc., the spread of the etchant caused by capillary action can be prevented. Liquid etchants can also be used in this process. Furthermore, in... Figure 8A In the example shown, the surface of the exposed metal foil 10 and the dielectric film D form approximately the same plane, but depending on the etching conditions, such as Figure 9 As shown, it can also sometimes be a roughened metal foil 10 with a protruding shape.

[0080] Next, after removing the anti-corrosion layer 61 ( Figure 10 Insulating components 21 and 22 are formed on the upper surface 11 of the metal foil 10. Figure 11A , 11B The insulating components 21 and 22 can be formed using photolithography, screen printing, gravure printing, inkjet printing, etc. Therefore, the cross-sections of the insulating components 21 and 22 are as follows: Figure 11A As shown, the side surface is conical. Here, the location of the insulating component 21 can be as follows: Figure 12A The portion shown overlaps with the exposed portion of the metal foil 10, and can also be as follows: Figure 12B The portion shown does not overlap with the exposed portion of the metal foil 10. Furthermore, the cross-sections of the insulating components 21 and 22 do not need to be bilaterally symmetrical, such as... Figure 13 As shown, taking the centerline C in the thickness direction of the metal foil 10 as a reference, the angle θc of the outer portion is reduced compared to the angle θb of the portion located inside the ring formed by the insulating member 21. This allows the tapered surface of the outer portion of the ring to be wider than the tapered surface of the inner portion. In the insulating member 21, the side forming the inner portion is connected to the conductive member 32 or the terminal electrode 52, and the side forming the outer portion is connected to the conductive member 31 or the terminal electrode 51. By adopting the above structure, abnormal stress is not generated during the shrinkage process when forming the insulating members 21 and 22, reducing cracks in the roughened portions and improving the yield.

[0081] Next, a photosensitive resist layer is formed on the upper surface 11 of the metal foil 10, and then exposed and developed to form a patterned resist layer 64. Figure 14A , 14BAn opening 65 is provided on the resist layer 64 to expose a region located on the outer side of the insulating member 22. The resist layer 64 is larger than the insulating member 22, thereby covering a portion of the outer side of the insulating member 22. The resist layer can be positive or negative.

[0082] Next, the metal foil 10 is removed by using the resist layer 64 as a mask, thus monolithizing the metal foil 10. Figure 15A , 15B As a method for removing the metal foil 10, wet etching using an etchant such as an acid can be employed. In this case, even if a liquid etchant is used, the etchant will not extend beyond the insulating component 22. When the metal foil 10 is monolithically formed, the etching conditions are controlled such that the side surface 13, which serves as the cross-section, is conical and its angle θa is 20° < θa < 80°.

[0083] To achieve higher precision in monolithic fabrication, as described above, it is preferable that the grain size of the central portion (non-coarsened portion) of the metal foil 10 is less than 15 μm in the planar direction and less than 5 μm in the thickness direction. This is because when the grain size of the metal foil 10 is 15 μm or more in the planar direction and 5 μm or more in the thickness direction, such as... Figure 16A , 16B As shown, the grains protrude from the inner wall of side 13, increasing the dimensional inhomogeneity of the monolithic metal foil 10. Conversely, if the grain size of the metal foil 10 is less than 15 μm in the planar direction and less than 5 μm in the thickness direction, such as Figure 17A , 17B As shown, the grains appearing on the side 13 are small, thus also reducing the size unevenness of the monolithic metal foil 10.

[0084] Next, after removing the anti-corrosion layer 64 ( Figure 18 , 19 Conductive components 31 and 32, made of conductive polymer material, are formed in the region surrounded by insulating component 22, and are in a paste or liquid form. Figure 20A , 20B In this configuration, conductive component 32 is located in the region surrounded by insulating component 21, and conductive component 31 is located outside the region surrounded by insulating component 21 and in the region surrounded by insulating component 22. Conductive components 31 and 32 are in a paste or liquid form, and thus, through capillary action, fill to the bottom of the porous layer 11a. Therefore, conductive component 31 is not in contact with the metal foil 10 but is in contact with the dielectric film D, while conductive component 32 is in contact with the metal foil 10. Alternatively, the terminal electrode 52 can be formed directly without forming conductive component 32.

[0085] Next, a seed layer 40 is formed on the entire surface. Figure 21The seed layer 40 can be formed using methods such as sputtering. Next, a photosensitive resist layer is formed on the upper surface 11 of the metal foil 10, and then exposed and developed to form a patterned resist layer 67. Figure 22A , 22B An opening 68 is provided on the resist layer 67, located outside the region surrounded by the insulating member 22 and the region surrounded by the insulating member 21, and an opening 69 is provided in the region surrounded by the insulating member 21. Thus, in the seed layer 40, the portion covering the conductive member 31 is exposed through the opening 68, and the portion covering the conductive member 32 is exposed through the opening 69. The resist layer can be either positive or negative.

[0086] By performing electroplating in this state, terminal electrodes 51 and 52 are formed. Figure 23A , 23B Next, the resist layer 67 is removed by ashing or other methods. Figure 24A , 24B ), remove the seed layer 40 ( Figure 25A , 25B Furthermore, after forming an insulating film 14 on the side 13 of the metal foil 10 (Fig. 26), the transport substrate 60 is removed by peeling or etching. Figure 27 ),but Figure 1A , 1B The thin-film capacitor 1 shown is now complete. Here, the insulating film 14 can be formed by oxidizing the side surface 13 of the metal foil 10 through an ashing process for removing the resist layer 67 and other heat treatment processes. Multiple terminal electrodes 51 and 52 can each be formed, as long as at least one pair is formed.

[0087] The thin-film capacitor 1 in this embodiment can be as follows: Figure 28 The multilayer substrate 100 shown can also be embedded as follows: Figure 29 It is shown mounted on the surface of the multilayer substrate 300.

[0088] Figure 28 The illustrated electronic circuit board has a structure in which a semiconductor IC 200 is mounted on a multilayer substrate 100. The multilayer substrate 100 is a multilayer substrate comprising multiple insulating layers and multiple wiring patterns. The multiple insulating layers include insulating layers 101 to 104, and the multiple wiring patterns include wiring patterns 111 and 112. The number of insulating layers is not particularly limited. Figure 28In the example shown, a thin-film capacitor 1 is embedded between insulating layers 102 and 103. Multiple bonding patterns, including bonding patterns 141 and 142, are provided on the surface of the multilayer substrate 100. The semiconductor IC 200 has multiple pad electrodes, including pad electrodes 201 and 202. For example, one of the pad electrodes 201 and 202 is a power terminal, and the other is a ground terminal. The pad electrode 201 and bonding pattern 141 are connected via solder 211, and the pad electrode 202 and bonding pattern 142 are connected via solder 212. Furthermore, bonding pattern 141 is connected to the terminal electrode 51 of the thin-film capacitor 1 via via conductor 121, wiring pattern 111, and via conductor 131. On the other hand, bonding pattern 142 is connected to the terminal electrode 52 of the thin-film capacitor 1 via via conductor 122, wiring pattern 112, and via conductor 132. Thus, the thin-film capacitor 1 functions as a decoupling capacitor relative to the semiconductor IC 200.

[0089] Figure 29 The illustrated electronic circuit board has a structure in which a semiconductor IC 400 is mounted on a multilayer substrate 300. The multilayer substrate 300 is a multilayer substrate comprising multiple insulating layers and multiple wiring patterns. The multiple insulating layers include insulating layers 301 and 302, and the multiple wiring patterns include wiring patterns 311 and 312. The number of insulating layers is not particularly limited. Figure 29 In the example shown, a thin-film capacitor 1 is mounted on the upper surface of the surface 300a of the multilayer substrate 300. Multiple bonding patterns, including bonding patterns 341 to 344, are provided on the surface 300a of the multilayer substrate 300. The semiconductor IC 400 has multiple pad electrodes, including pad electrodes 401 and 402. For example, one of the pad electrodes 401 and 402 is a power terminal, and the other is a ground terminal. The pad electrode 401 and bonding pattern 341 are connected via solder 411, and the pad electrode 402 and bonding pattern 342 are connected via solder 412. Furthermore, bonding pattern 341 is connected to the terminal electrode 51 of the thin-film capacitor 1 via via conductor 321, wiring pattern 311, via conductor 331, and solder 413. On the other hand, bonding pattern 342 is connected to the terminal electrode 52 of the thin-film capacitor 1 via via conductor 322, wiring pattern 312, via conductor 332, bonding pattern 344, and solder 414. Therefore, the thin-film capacitor 1 functions as a decoupling capacitor relative to the semiconductor IC400.

[0090] The above describes preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Various modifications can be made without departing from the spirit of the present invention, and these modifications are also included within the scope of the present invention.

[0091] Example

[0092] Multiple thin-film capacitor samples were fabricated, each with the same structure as the thin-film capacitor 1 shown in Figure 1, but with various settings including angle θa, thickness T of the metal foil 10, type and presence of the insulating film 14, and interference between the virtual straight line L3 and the insulating component 22. The sample's planar dimensions were 1.0 mm × 0.5 mm. The thin-film capacitor samples were then mounted on an evaluation multilayer substrate and subjected to thermal shock testing to evaluate the probability of mounting defects. Mounting defects included capacitance defects and insulation defects. A capacitance defect was defined as one where the actual capacitance was less than 80% of the design value. An insulation defect was defined as one where the insulation resistance value was more than one place lower than the design value. The results were then compared... Figure 30 As shown in the image.

[0093] like Figure 30 As shown, in samples B1-B3 with an angle θa greater than 80° and samples B4 and B5 with an angle θa less than 20°, the probability of installation failure is greater than 23%. In contrast, in samples A1-A6 with an angle θa greater than 20° and less than 80°, the probability of installation failure is less than 22%. In particular, in samples A2-A4 with an angle θa greater than 40° and less than 75°, the probability of installation failure is 13-14%.

[0094] Furthermore, as shown in samples A7 to A9, when the angle θa is set to approximately 60°, the thinner the thickness T of the metal foil 10, the lower the probability of installation defects. In particular, the probability of installation defects in samples A8 and A9, where the thickness T of the metal foil 10 is less than 100 μm, is less than 8%, and the probability of installation defects in sample A9, where the thickness T of the metal foil 10 is 48 μm, is 7%.

[0095] Furthermore, when the angle θa is set to 40° or more and 75° or less, in samples A10 to A32 where the side 13 of the metal foil 10 is covered by the insulating film 14, the probability of installation failure is 9% or less. In samples A10 to A29 where the virtual straight line L3 and the insulating component 22 do not interfere, the probability of installation failure is 6% or less, and particularly in samples A16 to A23, A28, and A29 where the insulating film 14 is made of resin, the probability of installation failure is 4% or less.

[0096] Explanation of reference numerals in the attached figures

[0097] 1. Thin film capacitor

[0098] 10 metal foil

[0099] 10a non-porous layer

[0100] 11. The upper surface of the metal foil

[0101] 11a porous layer

[0102] 12 Lower surface of metal foil

[0103] 12a porous layer

[0104] 13. Side of metal foil

[0105] 14 insulating film

[0106] 21, 22 Insulating components

[0107] 31, 32 Conductive components

[0108] 40 seed layers

[0109] 51 and 52 terminal electrodes

[0110] 60 Conveyor Base Material

[0111] Anti-corrosion layers 61, 64, and 67

[0112] Openings at points 62, 65, 68, and 69

[0113] 100 and 300 multilayer substrates

[0114] Insulation layers 101-104, 301, and 302

[0115] Wiring patterns 111, 112, 311, 312

[0116] 121, 122, 131, 132, 321, 322, 331, 332 through-hole conductors

[0117] 141, 142, 341-344 joining patterns

[0118] 200, 400 semiconductor ICs

[0119] 201, 202, 401, 402 pad electrodes

[0120] Solders 211, 212, and 411-414

[0121] Surface of 300a multilayer substrate

[0122] D dielectric film

[0123] E-barrier membrane

Claims

1. A thin-film capacitor, wherein, have: A metal foil, one of its main surfaces being roughened; A dielectric film covering one main surface of the metal foil, having an opening that partially exposes the metal foil; A first electrode layer is connected to the metal foil via the opening; as well as The second electrode layer is not in contact with the metal foil but is in contact with the dielectric film. The metal foil has another main surface located opposite to the first main surface, and a side surface connecting the first main surface and the other main surface. The angle formed by the other main surface and the side surface exceeds 20° but is less than 80°. The side is not covered by the dielectric film, but by an insulating film made of a resin material different from the dielectric film.

2. The thin-film capacitor according to claim 1, wherein, The angle is greater than 40° and less than 75°.

3. The thin-film capacitor according to claim 1, wherein, The thickness of the metal foil is less than 200 μm.

4. The thin-film capacitor according to claim 3, wherein, The thickness of the metal foil is less than 100 μm.

5. The film capacitor according to claim 4, wherein, The thickness of the metal foil is less than 50 μm.

6. The thin-film capacitor according to claim 1, wherein, The insulating film has a multilayer structure.

7. The thin-film capacitor according to claim 1, wherein, The first and second electrode layers are separated by an annular slit. The first electrode layer is disposed in the first region surrounded by the slit. The second electrode layer is disposed in a second region located outside the slit.

8. The thin-film capacitor according to claim 7, wherein, It also includes: a first insulating component disposed inside the slit, located between the first and second electrode layers.

9. The thin-film capacitor according to claim 8, wherein, It also includes: a second insulating component disposed on one of the main surfaces of the metal foil, surrounding the second electrode layer.

10. The thin-film capacitor according to claim 9, wherein, The virtual straight line extending along the side does not interfere with the second insulating component.

11. The thin-film capacitor according to claim 1, wherein, The second electrode layer includes a first conductive component made of a conductive polymer material and in contact with the dielectric film, and a second conductive component made of a metallic material and in contact with the first conductive component.

12. The thin-film capacitor according to claim 11, wherein, The first electrode layer includes a third conductive component that is in contact with the metal foil and is made of a conductive polymer material, and a fourth conductive component that is in contact with the third conductive component and is made of a metallic material.

13. The film capacitor according to claim 11, wherein, The first electrode layer includes a fourth conductive component that is in contact with the metal foil and is made of a metallic material.

14. The thin-film capacitor according to claim 1, wherein, The other main surface of the metal foil is roughened.

15. An electronic circuit board, wherein, have: A substrate having a wiring pattern; and The semiconductor IC disposed on the substrate and the thin-film capacitor according to any one of claims 1 to 14, The first and second electrode layers of the thin-film capacitor are connected to the semiconductor IC via the wiring pattern.

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