Capacitor

Abstract

The present invention realizes a capacitor that comprises composite bulk members with outstanding mechanical strength. The present invention is a capacitor that comprises: a conductive substrate; a plurality of fiber-like conductive members that are disposed on the substrate and are electrically connected to the substrate; a dielectric layer that covers the surface of the fiber-like conductive members; and a conductor layer that covers a surface of the dielectric layer. The plurality of fiber-like conductive members, the dielectric layer, the conductor layer, and a space formed between the plurality of fiber-like conductive members, which are covered by the dielectric layer and the conductor layer, constitute a composite bulk member. In a cross-section of the substrate in a thickness direction, the fiber-like conductive members have a maximum height of Hmax and the composite bulk member has one-side and an other-side outer peripheral regions that occupy a region from an outer edge of the composite bulk member to twice the maximum height Hmax and a central region that is sandwiched between the one-side and the other-side outer peripheral regions. At least one of the one-side and the other-side outer peripheral regions includes a portion in which the proportion S21 of the total area occupied by the fiber-like conductive members and the dielectric layer is higher than the proportion S11 of the total area occupied by the fiber-like conductive members and the dielectric layer in the central region.

Description

[Technical field]

[0001] The present disclosure relates to capacitors, and more particularly to capacitors having a conductor-dielectric-conductor structure. [Background technology]

[0002] It has been known that a capacitor can be manufactured by using a fibrous member. For example, Patent Document 1 describes a method of forming a capacitor having a metal-insulator-metal (MIM) structure by forming a fibrous member on a substrate (base surface) and sequentially forming a lower plate (metal), an insulating layer, and an upper plate (metal) on the surface of the fibrous member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2010-506391 [Non-patent literature]

[0004] [Non-Patent Document 1] Michael FL De Volder, Sei Jin Park, Sameh H Tawfick, Daniel O Vidaud and A John Hart, "Fabrication and electrical integration of robust carbon nanotube micropillars by self-directed elastocapillary densification", Journal of Micromechanics and Microengineering, 2011. Summary of the Invention [Problem to be solved by the invention]

[0005] If the fibrous member is conductive, a dielectric layer can be formed on the surface of the fibrous conductive member, and then a conductive layer can be formed to form a capacitor having a conductor-dielectric-conductor structure.

[0006] For example, vertically aligned carbon nanotubes (hereinafter, also referred to as "VACNTs") can be used as the multiple fibrous conductive members. VACNTs can be obtained by growing them at high density on a substrate to which a catalyst is attached. Usually, multiple adjacent VACNTs are entangled and integrated to form a forest.

[0007] The integrated VACNTs are covered with a dielectric layer and a conductive layer to form a composite bulk member, but the mechanical strength of the composite bulk member may be insufficient. If the composite bulk member is damaged during use of the capacitor, the performance of the capacitor will decrease.

[0008] An object of the present disclosure is to provide a capacitor including a composite bulk member having excellent mechanical strength. [Means for solving the problem]

[0009] According to the gist of the present disclosure, A conductive substrate; a plurality of fibrous conductive members disposed on the substrate and electrically connected to the substrate; a dielectric layer covering a surface of the fibrous conductive member; a conductive layer covering a surface of the dielectric layer, a plurality of the fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of the fibrous conductive members covered by the dielectric layer and the conductor layer constitute a composite bulk member; In one cross section along the thickness direction of the substrate, The fiber-shaped conductive member has a maximum height H max having The composite bulk member has a maximum height H from an outer edge of the composite bulk member. max and a central region sandwiched between the peripheral regions on one side and the other side, the peripheral regions occupying an area up to twice the area of ​​the central region on the one side and the other side, At least one of the peripheral regions on one side and the other side has an area occupancy ratio S of the total area of ​​the fibrous conductive member and the dielectric layer in the central region. 11 The total area occupancy ratio S of the fibrous conductive member and the dielectric layer compared to 21 A capacitor is provided that includes a portion having a high

[0010] According to the gist of the present disclosure, A conductive substrate; a plurality of fibrous conductive members disposed on the substrate and electrically connected to the substrate; a dielectric layer covering a surface of the fibrous conductive member; a conductive layer covering a surface of the dielectric layer, a plurality of the fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of the fibrous conductive members covered by the dielectric layer and the conductor layer constitute a composite bulk member; In one cross section along the thickness direction of the substrate, The fiber-shaped conductive member has a maximum height H max having The composite bulk member has a maximum height H from an outer edge of the composite bulk member. max and a central region sandwiched between the peripheral regions on one side and the other side, the peripheral regions occupying an area up to twice the area of ​​the central region on the one side and the other side, At least one of the peripheral regions on one side and the other side is a ratio S of the total area occupied by the fiber-shaped conductive member, the dielectric layer, and the conductor layer in the central region. 12 The total area occupancy ratio S of the fibrous conductive member, the dielectric layer and the conductor layer compared to 22 A capacitor is provided that includes a portion having a high

[0011] According to the gist of the present disclosure, A conductive substrate; a plurality of fibrous conductive members disposed on the substrate and electrically connected to the substrate; a dielectric layer covering a surface of the fibrous conductive member; a conductive layer covering a surface of the dielectric layer, a plurality of the fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of the fibrous conductive members covered by the dielectric layer and the conductor layer constitute a composite bulk member; In one cross section along the thickness direction of the substrate, the fiber-shaped conductive member has a maximum height H max having In one cross section parallel to an in-plane direction of the substrate, The composite bulk member has a maximum height H from an outer edge of the composite bulk member. max a peripheral region that occupies an area up to twice the area of ​​the central region surrounded by the peripheral region, The peripheral region is a ratio S of the total area occupied by the fibrous conductive member, the dielectric layer, and the conductor layer in the central region. 13 The total area occupancy ratio S of the fibrous conductive member, the dielectric layer and the conductor layer compared to 23 A capacitor is provided that includes a portion having a high Effect of the Invention

[0012] According to the present disclosure, a capacitor is provided that includes a composite bulk member having excellent mechanical strength. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a schematic cross-sectional view of a capacitor according to the first and second embodiments of the present disclosure. [Diagram 2] FIG. 2 is an enlarged view of part A in FIG. [Diagram 3] 2 is a schematic cross-sectional view taken along an in-plane direction of the substrate in FIG. 1. [Figure 4] 1A to 1C are schematic cross-sectional views of capacitors according to Modification 1 of Embodiment 1 and Modification 2 of Embodiment 2 of the present disclosure. [Diagram 5] FIG. 5 is an enlarged view of part B in FIG. [Figure 6] FIG. 11 is a schematic cross-sectional view of a capacitor according to a third embodiment of the present disclosure. [Figure 7] FIG. 7 is an enlarged view of part D in FIG. [Figure 8] 11 is a schematic cross-sectional view of a portion of a capacitor according to Modification 3 of Embodiment 3 of the present disclosure. FIG. [Figure 9] 1 shows electron microscope images taken from the side of a forest having inclined CNTs and a portion of a substrate obtained in Production Example 1. [Figure 10A] 1 is an SEM image of a portion of the outer peripheral region of a polished XZ cross section of a composite bulk member obtained in Manufacturing Example 1. [Figure 10B] 1 is an SEM image of a portion of the central region of a polished XZ cross section of a composite bulk member obtained in Manufacturing Example 1. [Figure 11A] 1 is an SEM image of a portion of the outer peripheral region of a polished XY cross section of a composite bulk member obtained in Manufacturing Example 1. [Figure 11B] 1 is an SEM image of a portion of the central region of a polished XY cross section of a composite bulk member obtained in Manufacturing Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, a capacitor according to one aspect of the present disclosure will be described in detail with reference to the illustrated embodiments. Note that the drawings include some schematic views and may not reflect actual dimensions or ratios. The present disclosure is not limited to these embodiments.

[0015] <Embodiment 1> FIG. 1 is a schematic cross-sectional view of a capacitor in the first embodiment. FIG. 1 shows a cross section along the thickness direction of a substrate 10. For convenience, FIG. 1 shows the substrate 10 and the outer shape of a composite bulk member 20, and omits a fibrous conductive member 21, a dielectric layer 22, a conductor layer 23, and a space 24. FIG. 2 is an enlarged view of part A in FIG. 1. In FIG. 2, a fibrous conductive member 21 sequentially covered with a dielectric layer 22 and a conductor layer 23 is shown. For convenience, FIG. 2 shows only a part of the substrate 10, the fibrous conductive member 21, the dielectric layer 22, and the conductor layer 23. FIG. 3 is a schematic cross-sectional view along the in-plane direction of the substrate in FIG. 1.

[0016] In the figure, the thickness direction of the substrate 10 is the Z direction. A straight line including the center C of the substrate 10 when the capacitor 1 is viewed from the Z direction and extending along the Z direction is the central axis AX. The center C of the substrate 10 is usually coaxial with the center of the capacitor 1. The direction perpendicular to the Z direction of a cross section obtained by cutting the capacitor 1 along a plane including the central axis AX and extending in the Z direction is the X direction (also referred to as the width direction in an XZ cross section). The X direction is an example of a direction parallel to the in-plane direction of the substrate 10. The direction perpendicular to the Z direction and the X direction is the Y direction (also referred to as the width direction in a YZ cross section).

[0017] The XZ section is a section obtained by cutting the capacitor 1 along a plane formed by a line extending in the X direction and a line extending in the Z direction and including the central axis AX. The XZ section is an example of a section along the thickness direction of the substrate 10. The YZ section is a section obtained by cutting the capacitor 1 along a plane formed by a line extending in the Y direction and a line extending in the Z direction and including the central axis AX. The YZ section is another example of a section along the thickness direction of the substrate 10. The XY section is a section obtained by cutting the capacitor 1 along a plane formed by a line extending in the X direction and a line extending in the Y direction. The XY section is a section parallel to the in-plane direction of the substrate 10. The center C of the substrate 10 is the center of the smallest circle that contains the substrate 10 when the capacitor 1 is viewed from the Z direction.

[0018] In an XZ cross section, the X direction is sometimes called the left-right direction. The right side of an element refers to the right side of the element. The left side of an element refers to the left side of the element.

[0019] (composition) The capacitor 1 includes a conductive substrate 10, a plurality of fibrous conductive members 21 disposed on the substrate 10 and electrically connected to the substrate 10, a dielectric layer 22 covering the surface of the fibrous conductive members 21, and a conductor layer 23 covering the surface of the dielectric layer 22. The capacitor 1 may have a conductive member (not shown) in contact with the conductor layer 23. The plurality of fibrous conductive members 21, the dielectric layer 22, the conductor layer 23, and spaces 24 formed between the plurality of fibrous conductive members covered by the dielectric layer 22 and the conductor layer 23 constitute a composite bulk member 20. The spaces 24 may be filled with a filler such as a resin. The conductive member will be described later.

[0020] In capacitor 1, the top of substrate 10 can be rephrased as a surface (surface 10a described later) that is parallel to a plane (XY plane) formed by a straight line extending in the X direction and a straight line extending in the Y direction, which is the outer surface of substrate 10.

[0021] The dielectric layer 22 may cover the surfaces of the fibrous conductive members 21 (excluding the areas directly bonded to the substrate 10) as well as the portions of the surface 10a of the substrate 10 between the plurality of fibrous conductive members 21 where the fibrous conductive members 21 are not arranged. The dielectric layer 22 may be formed on the outside of the plurality of fibrous conductive members 21, continuously with a dielectric portion 22a that covers the portions of the surface 10a of the substrate 10 where the fibrous conductive members 21 are not arranged. However, the composite bulk member 20 does not include the dielectric portion 22a.

[0022] The conductive layer 23 may cover the dielectric layer 22 between the multiple fibrous conductive members 21, in addition to the dielectric layer 22 covering the surface of the fibrous conductive members 21. The portion of the conductive layer 23 that covers the dielectric layer 22 between the multiple fibrous conductive members 21 may be understood as defining the bottom of the space 24 (e.g., the bottom of the trench). The conductive layer 23 may be formed continuously with a conductive portion 23a that covers the dielectric portion 22a outside the multiple fibrous conductive members 21. However, the composite bulk member 20 does not include the conductive portion 23a.

[0023] The fibrous conductive member 21 is directly bonded to the substrate 10. More specifically, the fibrous conductive member 21 is directly contacted and bonded to the substrate 10. The fibrous conductive member 21 is directly synthesized on the surface 10a of the substrate 10.

[0024] The multiple fibrous conductive members 21 are conductive (typically conductors) and can be at the same potential or voltage as one another by being electrically connected to the substrate 10. Thus, a conductor-dielectric-conductor structure is formed by the fibrous conductive members 21, the dielectric layer 22 and the conductor layer 23. Such a conductor-dielectric-conductor structure can be understood as corresponding to a so-called MIM structure (metal-insulator-metal structure). A capacitor 1 having such a structure can obtain a high capacitance density due to the large specific surface area of ​​the fibrous conductive members 21.

[0025] In a cross section in the thickness direction (here, the XZ cross section), the fiber-shaped conductive member 21 has a maximum height H max The composite bulk member 20 has a maximum height H in a cross section in the thickness direction from the outer edge of the composite bulk member 20 toward the central axis AX. max and a central region R1 sandwiched between the peripheral regions R2 on one side and the other side. In the following, the cross section in the thickness direction will be mainly described using the XZ cross section.

[0026] 2, in the cross section in the thickness direction, the fibrous conductive members 21 in the outer peripheral region R2 are denser than those in the central region R1. Therefore, the fibrous conductive members 21 in the outer peripheral region R2 are occupying a larger area than the total area occupied by the fibrous conductive members 21 and the dielectric layer 22 in the central region R1. 11 Compared to the total area occupied by the fibrous conductive member 21 and the dielectric layer 22, the ratio S 21 Includes high parts.

[0027] The outer peripheral region R2 is the "area occupancy ratio S 21 "including a portion having a high area ratio S" means that the area ratio S in at least a portion of the outer peripheral region R2 of any one cross section in the thickness direction is 21 is the area occupancy ratio S in a part of the central region R1 of the cross section in the same thickness direction. 11 In the entire cross section in the thickness direction, the area occupancy rate S is higher than 21 is the area occupancy rate S 11 It doesn't require anything higher.

[0028] "Area Occupancy Ratio S 11 Area occupancy rate S 21 The phrase "the space 24 in the peripheral region R2 is higher" can be rephrased as "the space 24 in the peripheral region R2 is narrower than the space 24 in the central region R1." Compared to a composite bulk member having a uniform area occupation ratio, the composite bulk member 20 according to this embodiment has a higher mechanical strength in the peripheral region R2. 11 Area occupancy rate S 21 "is higher" can also be rephrased as "the average number density N2 of the fibrous conductive members 21 present in the outer peripheral region R2 is higher than the average number density N1 of the fibrous conductive members 21 present in the central region R1."

[0029] If the space becomes smaller, the large specific surface area of ​​the fibrous conductive member 21 is lost, and as a result, the volumetric capacitance density of the capacitor 1 is reduced, and the performance of the capacitor 1 may be degraded. 21By increasing the thickness of the composite bulk member 20, the mechanical strength of the composite bulk member 20 can be improved while suppressing deterioration in the performance of the capacitor 1.

[0030] "Area Occupancy Ratio S 21 "High" refers to the area occupancy rate S 11 and S. 21 This means that the difference between the 21 / S 11 ≧1.05. 21 / S 11 may be 1.2 or more, may be 2 or more, or may be 5 or more.

[0031] (Composite bulk members) The composite bulk member 20 is composed of a plurality of fibrous conductive members 21 (hereinafter referred to as conductive fibers 21), a dielectric layer 22, a conductor layer 23, and spaces 24 formed between a plurality of conductive fibers 21 (hereinafter also simply referred to as coated conductive fibers 21) coated with the dielectric layer 22 and the conductor layer 23.

[0032] · Method for determining composite bulk member 20 The composite bulk member 20 can be determined from a cross section (e.g., an XZ cross section) in the thickness direction of the capacitor 1. As described above, the composite bulk member 20 does not include the dielectric portion 22a and the conductor portion 23a, and is therefore determined to exclude these.

[0033] First, any suitable filling resin is filled into the spaces 24 formed between the coated conductive fibers 21. Next, the center C of the substrate 10 when the capacitor 1 is viewed from the Z direction is determined.

[0034] A cross section (here, an XZ cross section) in the thickness direction of the capacitor 1 including the center C is exposed by polishing. The obtained XZ cross section (No. 1) is observed with a scanning electron microscope (SEM). In the SEM image of the XZ cross section (No. 1), the substrate 10 and a first member (not shown) arranged on the surface 10a of the substrate 10 and consisting of a conductive fiber 21, a dielectric layer 22 (and a dielectric portion 22a if present, the same below), a conductive layer 23 (and a conductive portion 23a if present, the same below), and a filling resin (corresponding to the above-mentioned space 24) can be confirmed. In addition, a conductive member may be present.

[0035] The SEM image is subjected to image processing to identify and distinguish the conductive fiber 21, the dielectric layer 22, the conductor layer 23, the filling resin (space 24), and further the conductive member in the first member. For the identification, elemental analysis by energy dispersive X-ray analysis (EDX) may be used in combination.

[0036] In the XZ cross section, the composite bulk member 20 is approximately rectangular. In the SEM image, the conductive fibers 21 near the four corners of the composite bulk member 20 are identified. In this identification, the portions of the SEM image including the respective corners may be enlarged so that the observation field of view becomes about 1 μm×1 μm.

[0037] In the SEM image, the leftmost conductive fiber 21, which is the first member closest to the substrate 10 and located at the leftmost position, is identified. Next, the dielectric layer 22 and the conductor layer 23 covering the leftmost conductive fiber 21 are determined. These may be continuous with the dielectric portion 22a and the conductor portion 23a, respectively. The thickness of the dielectric layer 22 (and the dielectric portion 22a, the same below) covering the conductive fiber 21 is approximately uniform in terms of the manufacturing method. Therefore, the outer edge of the dielectric layer 22 covering the leftmost conductive fiber 21 can be determined in consideration of the thickness of the dielectric layer 22 covering the other conductive fibers 21. The thickness of the conductor layer 23 (and the conductor portion 23a, the same below) covering the conductive fiber 21 via the dielectric layer 22 is also approximately uniform in terms of the manufacturing method. Therefore, the outer edge of the conductor layer 23 covering the leftmost conductive fiber 21 can be determined in consideration of the thickness of the conductor layer 23 covering the other conductive fibers 21.

[0038] A first straight line L1 is drawn which is tangent to the determined outer edge of the conductive layer 23 and parallel to the central axis AX. The first straight line L1 defines the boundary (a virtual boundary, the same applies below) between the dielectric layer 22 and the dielectric portion 22a, and the boundary between the conductive layer 23 and the conductive portion 23a. With respect to the first straight line L1, the dielectric layer 22 is located to the right, and the dielectric portion 22a is located to the left. With respect to the first straight line L1, the conductive layer 23 is located to the right, and the conductive portion 23a is located to the left. The above-mentioned dielectric portion 22a and conductive portion 23a are not included in the composite bulk member 20.

[0039] Similarly, the rightmost conductive fiber 21, which is closest to the substrate 10 and located on the rightmost side of the first member, is identified, and the dielectric layer 22 and the conductor layer 23 that cover the rightmost conductive fiber 21 are determined. A second straight line L2 is drawn that is tangent to the outer edge of the conductor layer 23 and parallel to the central axis AX. The second straight line L2 defines the boundary between the dielectric layer 22 and the dielectric portion 22a, and the boundary between the conductor layer 23 and the conductor portion 23a. With respect to the second straight line L2, the dielectric layer 22 is located on the left, and the dielectric portion 22a is located on the right. With respect to the second straight line L2, the conductor layer 23 is located on the left, and the conductor portion 23a is located on the right. The above-mentioned dielectric portion 22a and conductor portion 23a are not included in the composite bulk member 20.

[0040] Similarly, when the conductive layer 23 and the conductive member are in contact with each other, the outer edge of the conductive layer 23 can be determined taking into consideration the thickness of the conductive layer 23 that covers the other conductive fibers 21. The conductive member is not included in the composite bulk member 20.

[0041] The composite bulk member 20 is composed of a plurality of conductive fibers 21, a dielectric layer 22, a conductive layer 23, and a space 24, which are present in the region between a first line L1 and a second line L2. The contact points (T1 and T2) between the first line L1 and the second line L2 and the composite bulk member 20 are points that indicate the outer edge of the composite bulk member 20 in the XZ cross section. The contact points T1 and T2 are typically located on the surface 10a of the substrate 10.

[0042] Maximum height H max How to determine Maximum height H max is determined, for example, from the SEM image of the XZ cross section (No. 1) above. The end of the conductive fiber 21 that is the furthest away from the surface 10a of the substrate 10 in the Z direction is identified, and the distance in the Z direction between this end and the surface 10a is determined as the maximum height H max It is.

[0043] <Central area R1, outer area R2> 1, in the XZ cross section, the outer peripheral regions R2 are disposed at two locations, one side and the other side (hereinafter also referred to as the left side and the right side) in the X direction, sandwiching the central region R1. The outer peripheral regions R2 on one side and the other side face each other via the central region R1.

[0044] How to determine the central region R1 and the peripheral region R2 The peripheral region R2 is the SEM image of the XZ cross section (No. 1) above and the maximum height H max In the SEM image, from the contact points T1 and T2 toward the central axis AX (toward the center C when the contact points T1 and T2 are on the surface 10a of the substrate 10 as shown), the maximum height H max Points (P1 and P2) that are twice as far apart as the center line L1 are plotted. The region that includes point P1 and is to the left of a third line L3 extending in the Z direction is the outer circumferential region R2 on one side. The region that includes point P2 and is to the right of a fourth line L4 extending in the Z direction is the outer circumferential region R2 on the other side. The region sandwiched between the third line L3 and the fourth line L4 is the central region R1.

[0045] <Area Occupancy Rate S 11 ,S 21 〉 Area Occupancy Rate S 11 is the total area occupied by the conductive fibers 21 and the dielectric layer 22 in any part of the central region R1 in a cross section in the thickness direction (for example, an XZ cross section). 21 is the total area occupied by the conductive fibers 21 and the dielectric layer 22 in any part of the outer peripheral region R2 in the cross section in the thickness direction as described above. 21 is the area occupancy rate S 11 Even if the area occupancy ratio S of the other parts of the outer peripheral region R2 in the cross section in the thickness direction is lower than 21 is the area occupancy rate S 11 The higher the better.

[0046] Among them, in the entire outer peripheral region R2 of any one cross section in the thickness direction, the area occupancy ratio S 21 is the area occupancy rate S11 Higher is better.

[0047] Area Occupancy Rate S 11 ,S 21 The above relationship may be satisfied in a portion of any one cross section in the thickness direction. In any one cross section in the thickness direction, the outer peripheral region R2 on both sides has an area occupancy ratio S 11 Compared to the area occupancy rate S 21 This protects the relatively weak central region R1 from the left and right, thereby further improving the mechanical strength of the composite bulk member 20.

[0048] In a plurality of different cross sections in the thickness direction, the peripheral region R2 has an area occupancy ratio S 11 Compared to the area occupancy rate S 21 In this case, the mechanical strength of the composite bulk member 20 is further improved. "Including high portions in a plurality of cross sections in the thickness direction" means that the outer peripheral region R2 in at least two different cross sections in the thickness direction has an area occupancy ratio S 11 Compared to the area occupancy rate S 21 In all cross sections in the thickness direction, the peripheral region R2 includes a portion where the area occupancy ratio S 11 Compared to the area occupancy rate S 21 It is not necessary that the composition include a portion having a high

[0049] In at least two different cross sections in the thickness direction, the outer peripheral region R2 on one side and the outer peripheral region R2 on the other side each have an area occupancy ratio S 11 Compared to the area occupancy rate S 21 may include a portion where

[0050] The different thickness cross sections may be XZ cross sections and YZ cross sections. The different thickness cross sections may be obtained by rotating the XZ cross section by less than 360 degrees around the central axis AX.

[0051] Area Occupancy Rate S 11may be 0.1 or more, may be 0.15 or more, or may be 0.20 or more. 11 may be 0.5 or less, may be 0.4 or less, or may be 0.35 or less.

[0052] Area Occupancy Rate S 21 may be 0.2 or more, may be 0.25 or more, or may be 0.30 or more. 21 may be 0.7 or less, may be 0.5 or less, or may be 0.45 or less.

[0053] Area Occupancy Rate S 11 ,S 21 Calculation method Area Occupancy Rate S 11 ,S 21 is calculated as follows using the SEM image of the above XZ cross section (No. 1). In the SEM image, the composite bulk member 20, the peripheral region R2, and the central region R1 are identified. In the composite bulk member 20, the conductive fiber 21, the dielectric layer 22, the conductive layer 23, and the filled resin (space 24) are distinguished.

[0054] The total area of ​​the conductive fiber 21 and the dielectric layer 22 in the right peripheral region R2 is divided by the area of ​​the peripheral region R2 (i.e., the total area including the conductive fiber 21, the dielectric layer 22, the conductor layer 23, and the filled resin). This gives the area occupancy ratio S of the right peripheral region R2. 21 Similarly, the area occupancy ratio S of the left peripheral region R2 is calculated. 21 Similarly, the area occupancy rate S of the central region R1 is calculated. 11 Calculate.

[0055] The observation field of view at this time may be large enough to observe only a part of the central region R1. Similarly, the observation field of view may be large enough to observe only a part of the peripheral region R2. The size of the observation field of view may be, for example, about 1 μm×1 μm. This makes it easier to distinguish between the conductive fiber 21, the dielectric layer 22, the conductor layer 23, and the filling resin.

[0056] Area occupancy ratio S in multiple cross sections in the thickness direction 11 ,S 21 The maximum height H is calculated as follows. First, for the composite bulk member 20 with the XZ cross section (No. 1) exposed, another cross section in the thickness direction (for example, the YZ cross section, No. 2) is exposed by polishing, and the SEM image is observed. max Since the outer peripheral region R2 on one side has already been measured, the outer peripheral region R2 on one side is determined based on the measurement. Next, the image processing is performed as described above (using EDX analysis as necessary, as below) to obtain the area occupancy ratio S of the outer peripheral region R2 on one side that appears in the SEM image. 21 The cross section (No. 2) represents a portion (half) of the cross section in the thickness direction of the composite bulk member 20, but the remainder of the cross section (No. 2) may be considered to have a similar configuration to the portion of the XZ cross section. Therefore, the area occupancy ratio S of the outer peripheral region R2 on the other side is calculated. 21 The area occupancy ratio S of the other parts of the central region R1 can be regarded as being the same as that of the other parts of the central region R1. 11 It can be considered that the area occupancy ratio S in the cross section in the thickness direction is the same as that in the SEM image of the cross section (No. 2). This operation is repeated for a plurality of cross sections in different thickness directions as necessary. Then, a plurality of SEM images are obtained, and image processing, etc. are performed to obtain the area occupancy ratio S in the cross sections in the thickness direction. 11 ,S 21 Calculate.

[0057] <others> Whether the SEM image of the XZ cross section (No. 1) used above is an SEM image of a cross section in the thickness direction of the substrate 10 can be confirmed by the thickness and width of the substrate 10 being observed. If the thickness of the substrate 10 measured from the SEM image is greater than the original thickness of the substrate, the cross section can be determined not to be a cross section in the thickness direction. "Larger than the original thickness of the substrate" means that the thickness of the substrate 10 in the SEM image is 5% or more greater than the original thickness of the substrate 10. Also, if the width of the substrate 10 measured from the SEM image is smaller than the original width of the substrate (the distance between the two intersections of a straight line passing through the center of the substrate and both ends of the substrate), the cross section can also be determined not to be a cross section in the thickness direction. "Smaller than the original width of the substrate" means that the width of the substrate 10 in the SEM image is 5% or more smaller than the original width of the substrate 10.

[0058] In order to confirm that the above SEM image is of a cross section in the thickness direction, it is desirable that the observation field by SEM is wide enough (e.g., 5 μm×5 μm or more) to confirm the front surface 10a, back surface 10b, and both ends of the substrate 10. On the other hand, the observation field may be narrower (e.g., about 1 μm×1 μm) in order to identify and / or distinguish the components of the composite bulk member 20 and calculate the area occupation ratio.

[0059] Each component will be described below. <Conductive fiber> In the present disclosure, the conductive fiber 21 is not particularly limited as long as its longitudinal dimension (length) is larger (preferably significantly larger) than the maximum cross-sectional dimension perpendicular to the longitudinal direction and the conductive fiber 21 is roughly in the form of a long, thin thread.

[0060] The average length of the conductive fibers 21 may be longer in terms of increasing the capacity density per area. The average length of the conductive fibers 21 may be, for example, several μm or more, 20 μm or more, 50 μm or more, 100 μm or more, 500 μm or more, 750 μm or more, 1000 μm or more, or 2000 μm or more. The upper limit of the average length of the conductive fibers 21 may be appropriately selected, but the length of the conductive fibers 21 may be, for example, 10 mm or less, 5 mm or less, or 3 mm or less. In one embodiment, the average length of the conductive fibers 21 is 50 μm or more. The average length of the conductive fibers 21 may be 50 μm or more and 3 mm or less.

[0061] The average length of the conductive fibers 21 can be calculated from the SEM image of the XZ cross section (No. 1) above. The average length of the conductive fibers 21 is the average value of the lengths of at least five or more conductive fibers 21.

[0062] The average number density (also referred to as the "average number density") of the conductive fibers 21 may be larger in order to increase the volume density per area and to increase the mechanical strength of the composite bulk member 20. The average number density N2 of the conductive fibers 21 in the peripheral region R2 is 10 8 book / cm 2 The average number density N2 can be 10 13 book / cm 2 may be less than or equal to 10 11 book / cm 2 may be less than or equal to 10 10 book / cm 2 It may be the following:

[0063] In particular, the average length of the conductive fibers 21 is 50 μm or more, and the average number density N2 in the outer peripheral region R2 is 10 8 book / cm 2 This allows the conductive fibers 21 densely packed in the outer circumferential region R2 to easily come into contact with other conductive fibers 21, and the mechanical strength of the composite bulk member 20 is more likely to be increased.

[0064] The ratio N2 / N1 of the average number density N2 of the multiple conductive fibers 21 in the central region R1 to the average number density N1 is, for example, 2 or more. This makes it easier to increase the mechanical strength of the composite bulk member 20. The ratio N2 / N1 may be 5 or more, 10 or more, or 50 or more. The ratio N2 / N1 may be 1000 or less, 500 or less, or 100 or less.

[0065] Calculation method for average number densities N1 and N2 The average number density of the conductive fibers 21 is the area occupancy ratio S 11 ,S 21 First, the height H of the sample from the surface 10a of the substrate 10 is the maximum height H max An XY cross section at a first position, which is 20% or less (typically 10% or less) of the XY cross section at the first position, is exposed by polishing. At this time, the XY cross section obtained may cut the dielectric portion 22a or the conductor portion 23a, or may not cut the dielectric portion 22a or the conductor portion 23a. Although the obtained XY cross section shows a part (which may be half or less) of the XY cross section of the composite bulk member 20, the remainder of the XY cross section may be considered to have a similar configuration to the obtained part of the XY cross section.

[0066] The obtained XY cross section is observed by SEM, and a central region R1 and a peripheral region R2 are determined as follows. As shown in Fig. 3, the SEM image shows the outer edge of the composite bulk member 20. However, one side of the outer edge of the composite bulk member 20 in the SEM image is a cutting line CL for exposing the XZ cross section. The SEM image may further show the surface 10a of the substrate 10, or the dielectric portion 22a or the conductor portion 23a covering the surface 10a.

[0067] First, as described above, the composite bulk member 20 is divided into the conductive fibers 21, the dielectric layer 22, the conductor layer 23, and the filled resin (space 24) by image processing. Next, in the SEM image, portions (points) of the multiple conductive fibers 21 that are on the outermost side of the composite bulk member 20 are identified. In the above XY cross section, the outer edge of the composite bulk member 20 and the outer edge of the substrate 10 may be considered to be similar, except for the cutting line CL. A line is drawn that includes the multiple plotted points and is similar to the outer edge of the substrate 10, except for the cutting line CL. This line is the outer edge of the composite bulk member 20 in the XY cross section.

[0068] From any point on the obtained perimeter to the opposite perimeter, the maximum height H max A point that is twice as far away as the line CL is plotted. This operation is repeated for multiple different points (e.g., four points) on the outer edge, and a line that includes the plotted multiple points and is similar to the outer edge of the composite bulk member 20 excluding the cutting line CL is drawn. This line is the boundary between the outer peripheral region R2 and the central region R1. The region from this line to the outer edge of the composite bulk member 20 is the outer peripheral region R2, and the inner region surrounded by this line and the cutting line CL is the central region R1.

[0069] In the composite bulk member 20, the outer peripheral region R2 is disposed so as to surround the central region R1 as can be seen from Fig. 3. Part of the outer edge of the composite bulk member 20 is indicated by lines L5 and L6. Part of the boundary between the outer peripheral region R2 and the central region R1 is indicated by lines L7 and L8. The lines L5 and L6 correspond to lines that include the tangent points T1 and T2 in Fig. 1 and are aligned in the Y direction. The lines L7 and L8 correspond to lines that include the points P1 and P2 in Fig. 1 and are aligned in the Y direction.

[0070] The number of conductive fibers 21 present in a portion of the determined peripheral region R2 (for example, a region of 5 μm × 5 μm) is counted to determine the number of conductive fibers 21 per unit area (number density). This operation is repeated to obtain number densities in five or more fields of view, and their average value is defined as the average number density N2 of the conductive fibers 21 in the peripheral region R2. The average number density N1 of the conductive fibers 21 in the central region R1 is calculated in the same manner.

[0071] Whether the SEM image of the XY cross section used above is an SEM image of a cross section parallel to the in-plane direction of the substrate 10 can be confirmed by the cross-sectional shape of the conductive fiber 21. At the first position, most of the conductive fibers 21 extend in the Z direction, and the cross-sectional shape is almost circular. Therefore, if the cross section of the conductive fiber 21 is flat, it can be determined that the cross section is not an XY cross section. "The cross section of the conductive fiber 21 is flat" means that the ratio of the major axis to the minor axis of the cross section of the conductive fiber 21 (major axis / minor axis) is 1.41 or more. The major axis is the longest diameter that passes through the center of the cross section of the conductive fiber 21. The minor axis is the shortest diameter that passes through the center of the cross section of the conductive fiber 21. The center of the cross section of the conductive fiber 21 is the center of the smallest circle that contains the cross section of the conductive fiber 21.

[0072] The maximum cross-sectional dimension of the conductive fiber 21 may be, for example, 0.1 nm or more, 1 nm or more, or 10 nm or more. The maximum cross-sectional dimension of the conductive fiber 21 may be, for example, 1 nm or more, or 10 nm or more. The maximum cross-sectional dimension of the conductive fiber 21 may be less than 1000 nm, 800 nm or less, or 600 nm or less.

[0073] The maximum cross-sectional dimension of the conductive fiber 21 can be calculated from the SEM image of the XY cross section used to calculate the average number densities N1 and N2. The maximum cross-sectional dimension of the conductive fiber 21 is the average value of the maximum cross-sectional dimensions of at least five or more conductive fibers 21.

[0074] The conductive fiber 21 may be a conductive nanofiber (having a maximum cross-sectional dimension on the nanoscale (1 nm or more and less than 1000 nm)). The conductive nanofiber may be, for example, a conductive nanotube (hollow, preferably cylindrical) or a conductive nanorod (solid, preferably cylindrical). A nanorod that is conductive (including semiconductive) is also called a nanowire.

[0075] Examples of conductive nanofibers that can be used in the present disclosure include carbon nanofibers. Examples of conductive nanotubes that can be used in the present disclosure include metal nanotubes, organic conductive nanotubes, and inorganic conductive nanotubes. Typically, the conductive nanotubes can be carbon nanotubes or titania carbon nanotubes. Examples of conductive nanorods (nanowires) that can be used in the present disclosure include silicon nanowires, metal nanowires (particularly silver nanowires), and conductive polymer wires.

[0076] The conductive fibers 21 may have a higher strength than the dielectric layer 22 in that the mechanical strength of the composite bulk member 20 is more likely to be increased. The strength of the conductive fibers 21 is 5 Mpa / (nm) 2 More than 150Gpa / (nm) 2 This allows the conductive fiber 21 to function as a core material of the composite bulk member 20, and is expected to suppress the occurrence of cracks in the composite bulk member 20. The strength of the conductive fiber 21 may be 10 Mpa / (nm) or less. 2 or more, 10 Gpa / (nm) 2 The strength of the conductive fiber 21 may be 100 Gpa / (nm) or more. 2 It may be the following:

[0077] 5Mpa / (nm) 2 More than 150Gpa / (nm) 2 The conductive fiber 21 having the following strength may be at least one type selected from the group consisting of carbon nanotubes, metal nanowires, and conductive polymer wires.

[0078] In particular, the conductive fibers 21 may be carbon nanotubes, which have electrical and thermal conductivity.

[0079] The chirality of the carbon nanotubes is not particularly limited, and may be either a semiconducting type or a metallic type, or may be a mixture of these. From the viewpoint of reducing the resistance value, a higher ratio of metallic types is preferable.

[0080] The number of walls of the carbon nanotube is not particularly limited, and it may be either a single-walled SWCNT (single-walled carbon nanotube) with one wall or a multi-walled carbon nanotube (MWCNT) with two or more walls.

[0081] The conductive fibers 21 may be so-called vertically aligned carbon nanotubes (VACNTs). VACNTs have a large specific surface area. In addition, as described below, VACNTs can be manufactured by growing them in a vertically aligned state on the substrate 10, and therefore the maximum height H max This has the advantage that it is easy to control.

[0082] <Substrate> The substrate 10 has two main surfaces (front surface 10a and back surface 10b) facing each other, and may be in the form of, for example, a plate (substrate), a foil, a film, a block, or the like.

[0083] The material constituting the substrate 10 may be appropriately selected as long as it is conductive and can be electrically connected to the plurality of conductive fibers 21. For example, it may be a semiconductor material such as silicon, a conductive material such as metal (copper, aluminum, nickel), or an insulating (or relatively low conductive) material such as ceramic (silicon oxide) or resin. The substrate 10 may be made of a single material, a mixture of two or more materials, or a composite composed of two or more materials. It is preferable that the material constituting the substrate 10 is a metal, since it is easily usable as a contact with the outside, can have a low resistance value, and can withstand high temperatures.

[0084] The thickness of the substrate 10 is not particularly limited and may vary depending on the application of the capacitor 1. The substrate 10 may be provided with electrodes for contacting the outside and wiring for ensuring electrical conduction.

[0085] <Dielectric layer> The dielectric material constituting the dielectric layer 22 may be appropriately selected. For example, silicon dioxide, aluminum oxide, silicon nitride, tantalum oxide, hafnium oxide, barium titanate, and lead zirconate titanate may be used alone or in combination of two or more (for example, stacked).

[0086] The thickness of the dielectric layer 22 may be 10 nm or more, or may be 15 nm or more. By making the thickness of the dielectric layer 22 10 nm or more, it is possible to increase the insulation property and reduce the leakage current. The thickness of the dielectric layer 22 may be 1 μm or less, or may be 100 nm or less, or may be 70 nm or less. By making the thickness of the dielectric layer 22 1 μm or less, it is possible to obtain a larger electrostatic capacitance. In one embodiment, the thickness of the dielectric layer 22 is 10 nm or more and 1 μm or less.

[0087] The thickness of the dielectric layer 22 can be calculated from the SEM image of the XY cross section used to calculate the average number densities N1 and N2. The thickness of the dielectric layer 22 is the average value of the thicknesses of the dielectric layer 22 covering at least five or more conductive fibers 21.

[0088] If present, the material constituting the dielectric portion 22 a and the thickness of the dielectric portion 22 a may be similar to that of the dielectric layer 22 .

[0089] Conductive layer Examples of conductive materials constituting the conductor layer 23 include metals and conductive polymers (polymeric materials having conductivity and / or having conductivity imparted thereto, also referred to as organic conductive materials). These may be used alone or in combination of two or more kinds. The conductor layer 23 may be a laminate of multiple layers made of different conductive materials.

[0090] Examples of the metal include silver, gold, copper, platinum, aluminum, and an alloy containing at least two of these metals. Examples of the conductive polymer include PEDOT (polyethylenedioxythiophene), PPy (polypyrrole), and PANI (polyaniline), which may be doped with a dopant such as an organic sulfonic acid compound, for example, polyvinylsulfonic acid, polystyrenesulfonic acid, polyallylsulfonic acid, polyacrylicsulfonic acid, polymethacrylicsulfonic acid, poly-2-acrylamido-2-methylpropanesulfonic acid, or polyisoprenesulfonic acid.

[0091] The thickness of the conductor layer 23 may be 3 nm or more, or may be 10 nm or more. By making the thickness of the conductor layer 23 3 nm or more, the resistance value of the conductor layer 23 itself can be reduced. The thickness of the conductor layer 23 may be 500 nm or less, or may be 100 nm or less. In one embodiment, the thickness of the conductor layer 23 is 3 nm or more and 500 nm or less.

[0092] The thickness of the conductive layer 23 can be calculated from the SEM image of the XY cross section used to calculate the average number densities N1 and N2. The thickness of the conductive layer 23 is the average value of the thicknesses of the conductive layer 23 covering at least five or more conductive fibers 21.

[0093] If present, the material constituting conductive portion 23a and the thickness of conductive portion 23a may be similar to that of conductive layer 23.

[0094] ≪Space≫ A space 24 is formed between the coated conductive fibers 21. 21By increasing the height, the space 24 is reduced, and the mechanical strength of the composite bulk member 20 is increased.

[0095] <Conductive materials> The capacitor 1 may have a conductive member in contact with the conductive layer 23. The conductive member is electrically connected to the conductive layer 23, and serves to lead the electrode to the outside of the capacitor 1.

[0096] The conductive member does not contact the conductive fiber 21, the dielectric layer 22, or the substrate 10. The boundary between the conductive member and the conductive layer 23 can be confirmed in an SEM image. Alternatively, the boundary between the conductive member and the conductive layer 23 can be identified by elemental analysis using EDX. Furthermore, the boundary between the conductive member and the conductive layer 23 may be determined from the thickness of the conductive layer 23 in the portion not in contact with the conductive member.

[0097] The conductive member is formed, for example, by applying / supplying a carbon paste or a conductive polymer material to a predetermined surface / portion. Carbon paste and conductive polymer materials generally have a relatively high viscosity, and therefore are difficult to penetrate into the space 24 and difficult to reach the depth of the space 24 (for example, the surface 10a of the substrate 10). Therefore, the space 24 is maintained between the coated conductive fibers 21.

[0098] (Manufacturing method) The capacitor 1 of this embodiment can be obtained, for example, by a manufacturing method including the following: (a) depositing a catalyst on the surface 10a of the substrate 10 so that the amount of the catalyst deposited is greater on the outer edge than on the center; (b) growing a plurality of conductive fibers 21 on the surface 10a of the substrate 10 using a catalyst as a nucleus, thereby preparing a forest composed of the plurality of conductive fibers 21 directly bonded to the substrate 10 at one end; (c) forming a dielectric layer 22 (and a dielectric portion 22a, if present, hereinafter) covering the surfaces of the plurality of conductive fibers 21 by a sol-gel method; and (d) forming a conductive layer 23 (and conductive portion 23a, if present; the same applies below) covering the surface of the dielectric layer 22; Steps (a) to (d) will be described in more detail below.

[0099] Process (a) First, a catalyst is applied to the surface 10a of the substrate 10. Vertically aligned carbon nanotubes (VACNTs, conductive fibers 21) grow using this catalyst as a nucleus. By applying the catalyst so that the amount of applied catalyst is greater on the outer edge of the surface 10a of the substrate 10 than in the center, a dense portion of VACNTs can be formed on the edge of the resulting forest.

[0100] The substrate 10 may be a synthetic substrate for growing VACNTs. In general, the material of the synthetic substrate is not particularly limited, and for example, silicon oxide, silicon, gallium arsenide, aluminum, SUS, etc. can be used. In this embodiment, a substrate 10 having electrical conductivity is used as the synthetic substrate.

[0101] The catalyst may be iron, nickel, platinum, cobalt, or an alloy containing these metals. The catalyst may be attached to the substrate 10 by chemical vapor deposition (CVD), sputtering, physical vapor deposition (PVD), atomic layer deposition (ALD), or the like, and may be combined with lithography, etching, or other techniques in some cases. Process (b) Next, using the catalyst as nuclei, a plurality of VACNTs are grown on the surface 10a of the substrate 10. This results in a forest composed of a plurality of VACNTs directly bonded to the substrate 10 at one end.

[0102] The method for growing VACNTs is not particularly limited, and CVD, plasma-enhanced CVD, or the like can be used under heating as necessary. The gas used is not particularly limited, and for example, at least one selected from the group consisting of carbon monoxide, methane, ethylene, and acetylene, or a mixture of at least one of these with hydrogen and / or ammonia, or the like can be used. If desired, moisture may be present in the ambient atmosphere when growing VACNTs. As a result, VACNTs grow on the substrate 10 with the catalyst as a nucleus. The end of the VACNT on the surface 10a side of the substrate 10 is the fixed end that is fixed to the substrate 10 (generally via a catalyst), and the opposite end of the VACNT is the free end that is the growth point. The length and diameter of the VACNTs can vary depending on parameters such as gas concentration, gas flow rate, and temperature. That is, the length and diameter of the VACNTs can be adjusted by appropriately selecting these parameters.

[0103] As a result, a forest of VACNTs is produced on the substrate 10. Strictly speaking, the length of each VACNT in the resulting forest may vary (for example, within-plane variation) on the free end side due to differences in growth rate, etc. When VACNTs are grown on the substrate 10 to which a catalyst has been attached, the catalyst may be deactivated midway through the synthesis of the VACNTs, and some carbon nanotubes (CNTs) may stop growing. The CNTs whose growth has stopped are entangled with the continuing growing CNTs and pulled, causing their fixed ends to separate from the substrate 10 and be pulled up toward the tips of the VACNTs.

[0104] The multiple VACNTs (conductive fibers 21) obtained as described above are placed on the substrate 10, and one end of each VACNT is directly bonded to the substrate 10. However, as will be understood from the above explanation, some of the VACNTs do not need to be directly bonded to the substrate 10.

[0105] Process (c) Next, a dielectric layer 22 that covers at least the surface of the VACNTs is formed by a sol-gel method.

[0106] By appropriately selecting or setting the conditions for carrying out the sol-gel method, it is possible to control the thickness of the formed dielectric layer 22. For example, the feed composition of the liquid used in the sol-gel method, the solvent used for the feed (e.g., water, ethanol, isopropanol, acetone), the film formation time, the stirring speed, the temperature, etc. may be appropriately selected or set.

[0107] Thereafter, the solvent is removed by drying to form the dielectric layer 22.

[0108] Process (d) Subsequently, a conductive layer 23 is formed to cover the surface of the dielectric layer 22 .

[0109] The method for forming the conductive layer 23 is not particularly limited, and may be a liquid phase deposition method, a vapor phase deposition method, or a combination thereof. The liquid phase deposition method may be, for example, a sol-gel method, plating, etc. The vapor phase deposition method may be, for example, ALD, sputtering, CVD, etc.

[0110] For example, the conductor layer 23 can be formed by a liquid phase film formation method using a conductive polymer. More specifically, the conductor layer 23 can be formed by applying / supplying (e.g., coating or immersion) a liquid composition in which a conductive polymer is dissolved or dispersed in an organic solvent to a predetermined surface / portion. The conductive polymer can easily penetrate into the space formed between the multiple VACNTs covered with the dielectric layer 22, and the conductor layer 23 can be appropriately formed even in the deep part of the space (e.g., the bottom part).

[0111] In this manner, the capacitor 1 shown in FIGS. 1, 2 and 3 can be manufactured.

[0112] [Variation 1] Fig. 4 is a schematic cross-sectional view of a capacitor in Modification 1 of Embodiment 1. Fig. 4 is a cross-section corresponding to Fig. 1. Fig. 5 is an enlarged view of part B in Fig. 4, and corresponds to Fig. 2.

[0113] The first modification is different from the first embodiment in the outer shape of the composite bulk member. This different configuration will be described below. The other configurations are the same as those of the first embodiment, and the same reference numerals as those of the first embodiment will be used and the description thereof will be omitted.

[0114] As shown in Fig. 4, in a cross section in the thickness direction (here, an XZ cross section), a part of the outer edge of the peripheral region R2 of the capacitor 1A is inclined in the X direction. At this time, as shown in Fig. 5, in the peripheral region R2, the conductive fibers 21 are inclined with respect to the Z direction or bent in the X direction. Therefore, the space 24 that existed in the peripheral region R2 is compressed and reduced in size. As a result, in the peripheral region R2, the area occupation ratio S of the conductive fibers 21 and the dielectric layer 22 in the central region R1 is reduced. 11 The area occupancy ratio S of the conductive fiber 21 and the dielectric layer 22 compared to 21 The results include some areas where the value is high.

[0115] In addition, since the conductive fibers 21 are inclined with respect to the Z direction or bent in the X direction, at least two conductive fibers 21 can be in contact with each other in the outer peripheral region R2 with or without the dielectric layer 22. In other words, since the conductive fibers 21 are positioned so as to support each other in the outer peripheral region R2, the composite bulk member 20A is less likely to deform due to an external force. This also further improves the mechanical strength of the composite bulk member 20A.

[0116] (Manufacturing method) The capacitor 1A can be obtained, for example, by a manufacturing method including: (a') preparing a forest composed of a plurality of VACNTs (conductive fibers 21) disposed on a surface 10a of a substrate 10 and directly bonded to the substrate 10 at one end; (b') Tilt the VACNTs on the outside of the forest toward the center; (c) forming a dielectric layer 22 covering the surfaces of the plurality of VACNTs by a sol-gel method; and (d) forming a conductive layer 23 covering the surface of the dielectric layer 22;

[0117] Step (b') will be described in detail below. Step (a') is carried out in the same manner as steps (a) and (b) of embodiment 1, except that the catalyst is uniformly attached to the entire surface 10a of the substrate 10. Steps (c) and (d) are carried out in the same manner as steps (c) and (d) of embodiment 1.

[0118] Process (b') The VACNTs at the edge of the resulting forest are tilted toward the center. By immersing the forest in an appropriate solvent, the VACNTs at the edge of the forest can be tilted toward the center. When the forest is immersed in an appropriate solvent, the VACNTs, especially those on the outside of the forest, tend to aggregate with each other. On the other hand, the VACNTs near the center of the forest tend to remain upright. As a result, the VACNTs at the edge tilt toward the center.

[0119] The solvent is selected in consideration of the wettability of the VACNTs. If the wettability of the VACNTs is too low, the VACNTs do not easily aggregate together. On the other hand, if the wettability of the VACNTs is too high, the VACNTs excessively aggregate together, making it difficult to obtain a composite bulk member 20A suitable for the capacitor 1A. Suitable solvents include, for example, water, ethanol, isopropanol, and acetone. Among them, ethanol is preferred.

[0120] A surfactant may be added to the solvent. This allows the wettability of the VACNT to be easily adjusted. The surfactant may be anionic. The surfactant is appropriately selected in consideration of the charge and molecular weight of the hydrophilic group. Examples of the surfactant include sodium dodecyl sulfate, cetyltrimethylammonium bromide, and sodium dodecylbenzenesulfonate. The amount of the surfactant added is appropriately set in consideration of the wettability of the VACNT.

[0121] The immersion conditions are also set in consideration of the wettability of VACNTs. Immersion may be performed by immersing substrate 10 having the forest formed thereon into a solvent at room temperature (23°C±3°C) at a speed of 2 to 10 mm / sec (typically 5 mm / sec) so that the angle between substrate 10 and the liquid surface is approximately 90 degrees, in order to prevent excessive aggregation.

[0122] Forest aggregation is also described in Non-Patent Document 1.

[0123] The material of the dielectric layer 22 may be added to the solvent. This allows the bath used in step (b') to be used as is to carry out step (c). Step (b') and step (c) are carried out simultaneously or continuously in the same bath. In other words, the aggregation of VACNTs and the attachment of the material of the dielectric layer 22 to the surface of the VACNTs proceed simultaneously or continuously. The attachment of the material of the dielectric layer 22 to the surface of the VACNTs makes it easier to maintain an appropriate aggregation state between the VACNTs, and further progression of aggregation due to drying performed thereafter is suppressed. In this way, in terms of the ease of controlling the aggregation state, step (b') and step (c) may be carried out simultaneously or continuously. In this case, the film formation time may be 1 to 3 hours (typically 1.5 hours), and the stirring speed may be 150 to 500 rpm (typically 300 rpm).

[0124] In this manner, the capacitor 1A shown in FIGS. 4 and 5 can be manufactured.

[0125] <Embodiment 2> The second embodiment differs from the first embodiment in the elements used when calculating the area occupancy ratio. Specifically, when calculating the area occupancy ratio, the area of ​​the conductor layer 23 is used in addition to the areas of the conductive fibers 21 and the dielectric layer 22. The other configurations are the same as those of the first embodiment, and the same reference numerals as those of the first embodiment are used and the description thereof is omitted. The second embodiment will be described using the same Figures 1 to 3 as those of the first embodiment.

[0126] In the second embodiment, the peripheral region R2 is a ratio S of the total area occupied by the conductive fiber 21, the dielectric layer 22, and the conductive layer 23 in the central region R1. 12 The total area occupancy ratio S of the conductive fiber 21, the dielectric layer 22 and the conductive layer 23 compared to 22 Includes high parts.

[0127] "Area Occupancy Ratio S 12 Area occupancy rate S 22 "The occupancy ratio S of the outer peripheral region R2 is high" can also be rephrased as "the space existing in the outer peripheral region R2 is smaller than the space existing in the central region R1". Therefore, compared with a composite bulk member having a uniform occupancy ratio of the area, the composite bulk member 20 according to this embodiment has a higher mechanical strength in the outer peripheral region R2. 22 By increasing the thickness of the composite bulk member 20, the mechanical strength of the composite bulk member 20 can be improved while suppressing deterioration in the performance of the capacitor 1.

[0128] "Area Occupancy Ratio S 22 "High" refers to the above area occupancy rate S 12 and S. 22 This means that the difference between the 22 / S 12 ≧1.05. 22 / S 12 may be 1.2 or more, may be 2 or more, or may be 5 or more.

[0129] S 22 / S 12 If ≧1.05, the above S 21 / S 11 It is also acceptable to consider that the relationship ≧1.05 is satisfied. 21 / S 11 If ≧1.05, then S 22 / S 12 It is safe to assume that a relationship of ≥ 1.05 is also satisfied.

[0130] Area Occupancy Rate S 12 ,S 22can be calculated in the same manner as in the first embodiment, except that the total area of ​​the conductive fibers 21, the dielectric layer 22 and the conductive layer 23 is divided by the area of ​​the central region R1 or the peripheral region R2.

[0131] Area Occupancy Rate S 12 may be 0.10 or more, may be 0.15 or more, or may be 0.20 or more. 12 may be 0.50 or less, may be 0.40 or less, or may be 0.35 or less.

[0132] Area Occupancy Rate S 22 may be 0.2 or more, may be 0.25 or more, or may be 0.30 or more. 22 may be 0.70 or less, may be 0.50 or less, or may be 0.45 or less.

[0133] [Variation 2] Modification 2 differs from embodiment 2 in the outer shape of the composite bulk member. This different configuration is similar to the difference between embodiment 1 and its modification 1. Modification 2 will be described using the same Figs. 4 and 5 as modification 1.

[0134] As in the first modification, in the capacitor 1A of the second modification, in the peripheral region R2 of the XZ cross section, the conductive fibers 21 are inclined with respect to the Z direction or bent in the X direction. Therefore, the space 24 that existed in the peripheral region R2 is compressed and reduced in size. The peripheral region R2 is a ratio S of the total area occupied by the conductive fibers 21, the dielectric layer 22, and the conductor layer 23 in the central region R1. 12 The total area occupancy ratio S of the conductive fiber 21, the dielectric layer 22 and the conductive layer 23 compared to 22 The results include some areas where the value is high.

[0135] <Embodiment 3> The third embodiment differs from the first embodiment in the elements and cross sections used when calculating the area occupancy ratio. The different configurations are described below. The other configurations are the same as those of the first embodiment, and the same reference numerals as those of the first embodiment are used and the description thereof is omitted.

[0136] FIG. 6 is a schematic cross-sectional view of a capacitor in the third embodiment. FIG. 6 shows a cross section along the in-plane direction of the substrate 10. For convenience, FIG. 6 shows the substrate 10 and the outer edge of the composite bulk member 20B, and omits the conductive fiber 21, the dielectric layer 22, the conductive layer 23, and the space 24. FIG. 7 is an enlarged view of part D in FIG. 6. In FIG. 7, the conductive fiber 21 sequentially covered with the dielectric layer 22 and the conductive layer 23 is shown. For convenience, FIG. 7 shows only a part of the substrate 10, the conductive fiber 21, the dielectric layer 22, the conductive layer 23, and the space 24. An example of a cross section along the thickness direction of the substrate 10 of the capacitor in the third embodiment is shown in FIG. 1 and FIG. 2. FIG. 7 corresponds to the II cross section of FIG. 2.

[0137] (composition) The conductive fiber 21 constituting the composite bulk member 20B has a maximum height H max The composite bulk member 20B has a maximum height H max and a central region R1 surrounded by the peripheral region R2.

[0138] 7, in the XY cross section, the conductive fibers 21 in the outer peripheral region R2 are denser than those in the central region R1. Therefore, the outer peripheral region R2 has a larger area occupancy ratio S of the total area occupied by the conductive fibers 21, the dielectric layer 22, and the conductor layer 23 in the central region R1. 13 The total area occupancy ratio S of the conductive fiber 21, the dielectric layer 22 and the conductive layer 23 compared to 23 Includes high parts.

[0139] The outer peripheral region R2 is the "area occupancy ratio S 23"including a portion having a high area ratio S" means that the area ratio S in at least a portion of the peripheral region R2 of any one XY cross section is 23 The area occupancy rate S in a part of the central region R1 of the same XY cross section 13 In the entire XY cross section, the area occupancy rate S is higher than 23 is the area occupancy rate S 13 It doesn't require anything higher.

[0140] "Area Occupancy Ratio S 13 Area occupancy rate S 23 "has a high occupancy rate" can be rephrased as "the space 24 in the outer peripheral region R2 is narrower than the space 24 in the central region R1." Therefore, compared with a composite bulk member having a uniform occupancy rate, the composite bulk member 20B according to this embodiment has a higher mechanical strength in the outer peripheral region R2. In this embodiment, too, the above-mentioned occupancy rate S of only the outer peripheral region R2 is 23 By increasing the area occupancy ratio S, it is possible to improve the mechanical strength of the composite bulk member 20B while suppressing the deterioration of the performance of the capacitor 1B. 13 Area occupancy rate S 23 "The number density of the conductive fibers 21 present in the outer circumferential region R2 is higher than the number density of the conductive fibers 21 present in the central region R1." can also be rephrased as "the number density of the conductive fibers 21 present in the outer circumferential region R2 is higher than the number density of the conductive fibers 21 present in the central region R1."

[0141] "Area Occupancy Ratio S 23 "High" refers to the area occupancy rate S 13 and S. 23 This means that the difference between the 23 / S 13 ≧1.05. 23 / S 13 may be 1.2 or more, may be 2 or more, or may be 5 or more.

[0142] Area Occupancy Rate S 13 is the total area occupied by the conductive fibers 21 and the dielectric layer 22 in any part of the central region R1 of any one XY cross section. 23is the total area occupied by the conductive fibers 21 and the dielectric layer 22 in any part of the peripheral region R2 in the same XY cross section as above. 23 is the area occupancy rate S 13 Even if the area occupancy ratio S of the other parts of the peripheral region R2 in the XY cross section is lower than 23 The area occupancy rate S 13 The higher the better.

[0143] Among them, in the entire peripheral region R2 of any one XY cross section, the area occupancy ratio S 23 The area occupancy rate S 13 Higher is better.

[0144] Area Occupancy Rate S 13 ,S 23 The above relationship may be satisfied in a portion of any one XY cross section. In any one XY cross section, the outer peripheral region R2 has an area occupancy ratio S 13 Compared to the area occupancy rate S 23 This further improves the mechanical strength of the composite bulk member 20B.

[0145] In different XY cross sections, the peripheral region R2 has an area occupancy ratio S 13 Compared to the area occupancy rate S 23 In this case, the mechanical strength of the composite bulk member 20B is further improved. "Including high portions in a plurality of XY cross sections" means that the peripheral region R2 in at least two different XY cross sections has an area occupancy ratio S 13 Compared to the area occupancy rate S 23 In all XY cross sections, the peripheral region R2 includes a portion where the area occupancy ratio S 13 Compared to the area occupancy rate S 23 It is not necessary that the composition include a portion having a high

[0146] In at least two different XY cross sections, two peripheral regions R2 facing each other through a central region R1 have an area occupancy ratio S 13 Compared to the area occupancy rate S 23 may include a portion where

[0147] Area Occupancy Rate S 13 may be 0.08 or more, may be 0.10 or more, or may be 0.15 or more. 13 may be 0.50 or less, may be 0.40 or less, or may be 0.30 or less.

[0148] Area Occupancy Rate S 23 may be 0.15 or more, may be 0.20 or more, or may be 0.25 or more. 23 may be 0.70 or less, may be 0.50 or less, or may be 0.40 or less.

[0149] Maximum height H max How to determine Maximum height H max is determined in the same manner as in the first embodiment from an SEM image of the XZ cross section obtained in the same manner as in the first embodiment.

[0150] <Central region R1 and peripheral region R2> In the XY cross section, the outer circumferential region R2 is disposed so as to surround the periphery of the central region R1.

[0151] How to determine the central region R1 and the peripheral region R2 The central region R1 and the peripheral region R2 have a maximum height H max The central region R1 and the peripheral region R2 are determined in the same manner as in the determination of the central region R1 and the peripheral region R2 performed to calculate the average number densities N1 and N2 in the first embodiment, using the sample used in determining the central region R1 and the peripheral region R2. For this method, refer to Fig. 3. The XZ cross section and half of the XY cross section of the capacitor 1B are exposed in the sample.

[0152] How to determine the opposing outer perimeter area R2 The opposing peripheral region R2 has a maximum height H max The XY cross section can be determined from the XY cross section of the sample used to determine the outer circumferential region R2. In this XY cross section, a part (which may be less than half) of the XY cross section of the composite bulk member 20B is shown, but the remaining part of the XY cross section may be considered to have a similar configuration to the obtained part of the XY cross section. The XY cross section is shown in FIG. 3. FIG. 3 corresponds to FIG. 6, and FIG. 6 is an example supplementing the remaining part of the XY cross section of the composite bulk member 20B removed by cutting in FIG. 3. The opposing outer circumferential region R2 may be determined using FIG. 6.

[0153] 6, like FIG. 3, shows straight lines L5 and L6 that are part of the outer edge of the composite bulk member 20B, and straight lines L7 and L8 that are part of the boundary between the outer peripheral region R2 and the central region R1. In addition, FIG. 6 shows straight lines L9 and L10 that are the remaining part of the outer edge of the composite bulk member 20B, and straight lines L11 and L12 that are part of the boundary between the outer peripheral region R2 and the central region R1. When the outer edge of the composite bulk member 20B includes a curve, the straight lines L5 and L6 correspond to straight lines that include the left and right ends of the composite bulk member 20B, respectively, and are aligned along the Y direction. Similarly, the straight lines L9 and L10 correspond to straight lines that include the Y direction ends of the composite bulk member 20B, respectively, and are aligned along the X direction. When the boundary between the outer peripheral region R2 and the central region R1 includes a curve, the straight lines L7 and L8 correspond to straight lines that include the left and right ends of the central region R1, respectively, and are aligned along the Y direction. Similarly, straight lines L11 and L12 each include an end of the central region R1 in the Y direction and correspond to a straight line along the X direction.

[0154] In Figure 6, the opposing outer peripheral region R2 can be determined to be a combination of "the portion between straight lines L5 and L7 of the outer peripheral region R2" and "the portion between straight lines L8 and L10 of the outer peripheral region R2", and a combination of "the portion between straight lines L9 and L11 of the outer peripheral region R2" and "the portion between straight lines L10 and L12 of the outer peripheral region R2".

[0155] <Area Occupancy Rate S 13 ,S 23〉 The XY cross section of the above sample is observed by SEM. In the SEM image, the composite bulk member 20B, the central region R1, and the peripheral region R2 are already identified.

[0156] First, the composite bulk member 20B is divided into the conductive fiber 21, the dielectric layer 22, the conductor layer 23, and the filled resin (space 24) by image processing. Next, the total area of ​​the conductive fiber 21, the dielectric layer 22, and the conductor layer 23 in the peripheral region R2 is divided by the area of ​​the peripheral region R2 (i.e., the total area including the conductive fiber 21, the dielectric layer 22, the conductor layer 23, and the filled resin). This gives the area occupancy ratio S of the peripheral region R2. 23 Similarly, the area occupancy rate S of the central region R1 is calculated. 13 Calculate.

[0157] Area occupancy rate S in multiple XY cross sections 13 ,S 23 is calculated in the same manner as above, except that the cutting position is changed in sequence to the second position, the third position, etc. A plurality of XY cross sections are obtained from the same sample (capacitor 1B). For example, the first position is a height H max The first position is set to a position that is as high as possible and is 20% or less of the first position. Next, the second position is set to a position slightly lower than the first position, and the third position is set to a position even lower than the second position. In this manner, multiple different XY cross sections can be exposed from the same sample.

[0158] [Variation 3] Modification 3 differs from embodiment 3 in the outer shape of the composite bulk member. This different configuration is similar to the difference between embodiment 1 and its modification 1. The other configurations are similar to embodiment 1, and the same reference numerals as embodiment 1 are used, and the description thereof will be omitted.

[0159] Fig. 8 is a schematic cross-sectional view of a portion of a capacitor in Modification 3 of Embodiment 3. Fig. 8 shows a cross section along the in-plane direction of the substrate 10. An example of a cross section of the entire capacitor in Modification 3 along the in-plane direction of the substrate 10 is shown in Fig. 6. Fig. 8 corresponds to Fig. 7 and an enlarged view of part D in Fig. 6. An example of a cross section of the capacitor in Modification 3 along the thickness direction of the substrate 10 is shown in Figs. 4 and 5. Fig. 8 corresponds to the II-II cross section of Fig. 5.

[0160] As in the first and second modifications, in the capacitor 1C of the third modification, the conductive fibers 21 are inclined with respect to the Z direction or bent in the X direction in the outer peripheral region R2 of the XZ cross section. Therefore, the space 24 that existed in the outer peripheral region R2 is covered by the conductive fibers 21 and reduced in size. As a result, the outer peripheral region R2 is smaller than the total area occupation ratio S of the conductive fibers 21, the dielectric layer 22, and the conductor layer 23 in the central region R1. 13 The total area occupancy ratio S of the conductive fiber 21, the dielectric layer 22 and the conductive layer 23 compared to 23 The results include some areas where the value is high.

[0161] Although six embodiments of the present disclosure have been described above in detail, the present disclosure is not limited thereto. For example, any two or more of the features of the above-described embodiments may be combined.

[0162] In the composite bulk members 20 and 20A of the above-described embodiments, the conductive fibers 21 are directly bonded to the substrate 10, but this is not limiting. The conductive fibers 21 may be bonded to the substrate 10 via a conductive adhesive layer. The conductive fibers 21 may be bonded to the surface of the adhesive layer, or may be bonded to the adhesive layer by inserting their ends into the adhesive layer. The conductive adhesive layer is typically formed of a metal material.

[0163] In the composite bulk member 20A of the embodiment described above, the conductive fibers 21 in the outer circumferential region R2 are in contact with each other through the dielectric layer 22 or without the dielectric layer 22, but this is not limited thereto. The multiple conductive fibers 21 in the outer circumferential region R2 may be isolated from each other.

[0164] In the XY cross section of the capacitors 1 and 1B in the above-described embodiment, the outer shapes of the substrate 10 and the composite bulk members 20 and 20B are rectangular, but are not limited thereto. The outer shapes of the substrate 10 and the composite bulk members 20 and 20B in the XY cross section may be circular, elliptical, or any other polygonal shape than a rectangle.

[0165] In the capacitors A and 1A of the above-described embodiments, the conductive fibers 21 and / or the composite bulk members 20 and 20A may be present on the surface (side surface) of the substrate 10 connecting the front surface 10a and the back surface 10b.

[0166] In the above-described embodiment, the conductive fibers 21 in step (b) or (a') are carbon nanotubes (CNTs), but the conductive fibers 21 are not limited to these. The conductive fibers 21 may be other than CNTs.

[0167] In the above-described embodiment, a forest is provided on the substrate 10 in step (b) or (a'), but this is not limiting. The forest may be provided on another synthetic substrate and then transferred to the substrate 10. In this case, steps (c) or (b') and subsequent steps may be performed after the transfer. An adhesive layer may be provided on the substrate 10.

[0168] In the above-described embodiment, in step (b'), a part of the conductive fibers 21 is tilted by aggregation, but this is not limiting. A part of the conductive fibers 21 may be tilted by pressing the forest from the outside toward the center.

[0169] In the above-described embodiment, the dielectric layer 22 is formed by a sol-gel method in step (c), but the present invention is not limited to this. The dielectric layer 22 may be formed by a vapor phase film formation method (typically, a sputtering method). In this case, the solvent used in step (b) or (a') is removed before performing step (c). The dielectric layer 22 may be formed by a liquid phase film formation method (typically, a plating method) other than the sol-gel method. When the dielectric layer 22 is made of a metal oxide, a method in which plating and surface oxidation treatment are combined may be used. EXAMPLES

[0170] The present invention will be described more specifically with reference to the following Production Examples, but the present invention is not limited thereto. (Production Example 1) Capacitors having composite bulk members according to Modifications 1, 2 and 3 were manufactured.

[0171] (1) Forest preparation A catalyst was applied onto the surface of the Si substrate 10, and VACNTs were grown thereon to obtain a forest 200.

[0172] (2) Tilt of VACNT The substrate 10 on which the forest 200 was provided was immersed in a raw material liquid containing sodium dodecyl sulfate, ammonia, and ethanol. The immersion was carried out as follows. First, the substrate 10 on which the forest 200 was provided was immersed in the raw material liquid whose liquid temperature was room temperature (23°C ± 3°C) so that the angle between the substrate 10 and the liquid surface of the raw material liquid was approximately 90 degrees. The immersion speed was 5 mm / sec. The substrate 10 was then pulled out and dried.

[0173] The substrate 10 having the forest 200 formed thereon was observed with an electron microscope after being immersed in the raw material liquid and dried. An image of a portion of the substrate 10 having the forest 200 is shown in Figure 9. Figure 9 confirms that the CNTs at the edge of the forest 200 are inclined toward the center. For convenience, Figure 9 includes a dashed line indicating the outer edge of the forest 200 and the substrate 10.

[0174] (3) Formation of the dielectric layer A dielectric layer 22 was formed on the forest 200. In detail, the VACNTs on the substrate 10 were immersed in a raw material mixture of 3-aminopropyltriethoxysilane and ethanol, and the mixture was maintained at 25°C for 1.5 hours while stirring at 300 rpm, and then the substrate 10 was removed. Finally, the mixture was dried to form a dielectric layer 22 (SiO2) that covers the surfaces of the multiple CNTs (conductive fibers 21) on the substrate 10.

[0175] (4) Formation of the conductive layer Next, the substrate 10 was immersed in a dispersion containing PEDOT (polyethylenedioxythiophene) and PSS (polystyrene sulfonic acid) to form a conductive layer 23 (a PEDOT / PSS composite) on the dielectric layer 22. In this manner, a capacitor was obtained.

[0176] After filling the space present in the composite bulk member of the obtained capacitor with resin, the center C of the substrate 10 was determined by viewing the substrate 10 from the Z direction. Next, the XZ cross section including the center C was exposed by polishing. The obtained cross section was observed by SEM. From the SEM image, the maximum height H of the CNTs was max The average length of the fibrous conductive member was calculated to be 105 μm. It can be understood that the average length of the fibrous conductive member is 50 μm or more.

[0177] In the same SEM image, the area from the outer edge of the composite bulk component to about 200 μm is defined as the peripheral area R2, and the rest is defined as the central area R1. The area occupancy rate S in the cross section in the thickness direction is 11 ,S 21 and area occupancy rate S 12 ,S 22 was calculated as described above. In at least one cross section in the thickness direction, the area occupancy ratio S 22 is S 22 / S 12 ≧1.36. In addition, in any cross section in the thickness direction, the peripheral regions R2 on both sides had an area occupancy ratio S 12 Compared to the area occupancy rate S 22In addition, in any cross section in the thickness direction, the peripheral regions R2 on both sides have an area occupancy ratio S 11 Compared to the area occupancy rate S 21 It can be understood that this includes high parts.

[0178] Using a structure with multiple cross sections in the thickness direction partially exposed, the area occupancy rate S of CNTs in the XY cross section was 13 ,S 23 was calculated as above. In at least one cross section in the in-plane direction, the area occupancy ratio S 23 is S 23 / S 13 ≧1.53. In addition, in any cross section in the in-plane direction, the peripheral region R2 has an area occupancy ratio S 13 Compared to the area occupancy rate S 23 It can be understood that this includes high parts.

[0179] The average number density N2 of the conductive fibers 21 in the outer peripheral region R2 calculated from the cross section in the in-plane direction is 5.28 × 10 9 book / cm 2 The average number density N1 of the conductive fibers 21 in the central region R1 is 2.36 × 10 9 book / cm 2 (The ratio N2 / N1=2.24). The maximum cross-sectional dimension of the CNT was 33 nm. The thickness of the dielectric layer 22 was 51 nm. The thickness of the conductive layer 23 was 15 nm.

[0180] Fig. 10A is an SEM image of a part of the outer peripheral region of the polished XZ cross section of the composite bulk member obtained in Manufacturing Example 1. Fig. 10B is an SEM image of a part of the central region of the polished XZ cross section of the composite bulk member obtained in Manufacturing Example 1. In Figs. 10A and 10B, the linear whitish parts are the conductive fibers 21 covered with the dielectric layer 22 and the conductive layer 23, and the black parts are the filled resin corresponding to the space 24.

[0181] Fig. 11A is an SEM image of a part of the outer peripheral region of the polished XY cross section of the composite bulk member obtained in Manufacturing Example 1. Fig. 11B is an SEM image of a part of the central region of the polished XY cross section of the composite bulk member obtained in Manufacturing Example 1. In Figs. 11A and 11B, the circular whitish parts are the conductive fibers 21 covered with the dielectric layer 22 and the conductive layer 23, and the black parts are the filled resin corresponding to the spaces 24. [Industrial Applicability]

[0182] The capacitors of the present disclosure may be used in any suitable application, particularly in applications where high mechanical strength of the composite bulk member is required.

[0183] This application claims priority based on Japanese Patent Application No. 2022-175701, filed in Japan on November 1, 2022, the entire contents of which are incorporated herein by reference.

[0184] <1> A conductive substrate; a plurality of fibrous conductive members disposed on the substrate and electrically connected to the substrate; a dielectric layer covering a surface of the fibrous conductive member; a conductive layer covering a surface of the dielectric layer, a plurality of the fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of the fibrous conductive members covered by the dielectric layer and the conductor layer constitute a composite bulk member; In one cross section along the thickness direction of the substrate, The fiber-shaped conductive member has a maximum height H max having The composite bulk member has a maximum height H from an outer edge of the composite bulk member. max and a central region sandwiched between the peripheral regions on one side and the other side, the peripheral regions occupying an area up to twice the area of ​​the central region on the one side and the other side, At least one of the peripheral regions on one side and the other side has an area occupancy ratio S of the total area of ​​the fibrous conductive member and the dielectric layer in the central region. 11 The total area occupancy ratio S of the fibrous conductive member and the dielectric layer compared to 21 A capacitor, including a high <2> In one cross section along the thickness direction of the substrate, The outer peripheral regions on both sides have the area occupancy ratio S 11 Compared to the above, the area occupancy ratio S 21 Including the high <1> The capacitor according to claim 1 . <3> In each of a plurality of cross sections along a thickness direction of the substrate, At least one of the outer peripheral regions on one side and the other side has the area occupancy ratio S 11 Compared to the above, the area occupancy ratio S 21 Including the high <1> or <2> The capacitor according to claim 1 . <4> A conductive substrate; a plurality of fibrous conductive members disposed on the substrate and electrically connected to the substrate; a dielectric layer covering a surface of the fibrous conductive member; a conductive layer covering a surface of the dielectric layer, a plurality of the fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of the fibrous conductive members covered by the dielectric layer and the conductor layer constitute a composite bulk member; In one cross section along the thickness direction of the substrate, The fiber-shaped conductive member has a maximum height H max having The composite bulk member has a maximum height H from an outer edge of the composite bulk member. max and a central region sandwiched between the peripheral regions on one side and the other side, the peripheral regions occupying an area up to twice the area of ​​the central region on the one side and the other side, At least one of the peripheral regions on one side and the other side is a ratio S of the total area occupied by the fiber-shaped conductive member, the dielectric layer, and the conductor layer in the central region. 12 The total area occupancy ratio S of the fibrous conductive member, the dielectric layer and the conductor layer compared to 22 A capacitor, including a high <5> In one cross section along the thickness direction of the substrate, The outer peripheral regions on both sides have the area occupancy ratio S 12 Compared to the above, the area occupancy ratio S 22 Including the high <4> The capacitor according to claim 1 . <6> In each of a plurality of cross sections along a thickness direction of the substrate, At least one of the outer peripheral regions on one side and the other side has the area occupancy ratio S 12 Compared to the above, the area occupancy ratio S 22 Including the high <4> or <5> The capacitor according to claim 1 . <7> A conductive substrate; a plurality of fibrous conductive members disposed on the substrate and electrically connected to the substrate; a dielectric layer covering a surface of the fibrous conductive member; a conductive layer covering a surface of the dielectric layer, a plurality of the fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of the fibrous conductive members covered by the dielectric layer and the conductor layer constitute a composite bulk member; In one cross section along the thickness direction of the substrate, the fiber-shaped conductive member has a maximum height H max having In one cross section parallel to an in-plane direction of the substrate, The composite bulk member has a maximum height H from an outer edge of the composite bulk member. max a peripheral region that occupies an area up to twice the area of ​​the central region surrounded by the peripheral region, The peripheral region is a ratio S of the total area occupied by the fibrous conductive member, the dielectric layer, and the conductor layer in the central region. 13 The total area occupancy ratio S of the fibrous conductive member, the dielectric layer and the conductor layer compared to 23 A capacitor, including a high <8> In one cross section parallel to an in-plane direction of the substrate, In the outer peripheral region, both of the portions on one side and the other side facing each other across the central region have the area occupancy ratio S 13 Compared to the above, the area occupancy ratio S 23 Including the high <7> The capacitor according to claim 1 . <9> In each of a plurality of cross sections parallel to an in-plane direction of the substrate, The peripheral region has the area occupancy ratio S 13 Compared to the above, the area occupancy ratio S 23 Including the high <7> or <8> The capacitor according to claim 1 . <10> The thickness of the dielectric layer is 10 nm or more. <1> ~ <9> 2. The capacitor according to claim 1 . <11> The average number density N2 of the plurality of fibrous conductive members in the outer circumferential region is 10 8 book / cm 2 That's all. <1> ~ <10> 2. The capacitor according to claim 1 . <12> The average length of the plurality of fibrous conductive members is 50 μm or more. <1> ~ <11> 2. The capacitor according to claim 1 . <13> A ratio N2 / N1 of an average number density N2 of the plurality of fibrous conductive members in the outer circumferential region to an average number density N1 of the plurality of fibrous conductive members in the central region is 2 or more. <1> ~ <12> 2. The capacitor according to claim 1 . <14> The fiber-shaped conductive member is a carbon nanotube. <1> ~ <13> 2. The capacitor according to claim 1 . [Explanation of symbols]

[0185] 1,1A,1B,1C Capacitor 10 Substrate 10a surface 10b back side 20, 20A, 20B Composite bulk members 21 Fibrous conductive material (conductive fiber) 22 Dielectric layer 22a Dielectric part 23 Conductive layer 23a Conductor part 24 Space 200 Forest C Center of the board AX center axis R1 central area R2 outer area L1, L2, L5, L6, L9, L10: Boundaries between dielectric layers and dielectric parts L3, L4, L7, L8, L11, L12: Boundary between central region R1 and peripheral region R2 T1: Contact point between the first straight line L1 and the composite bulk material T2: Contact point between the second straight line L2 and the composite bulk material P1 Maximum height H from tangent point T1 toward central axis AX max A point twice as far away as P2 Maximum height H from tangent point T2 toward central axis AX max A point twice as far away as

Claims

1. A conductive substrate; a plurality of fibrous conductive members disposed on the substrate and electrically connected to the substrate; a dielectric layer covering a surface of the fibrous conductive member; a conductive layer covering a surface of the dielectric layer, a plurality of the fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of the fibrous conductive members covered by the dielectric layer and the conductor layer constitute a composite bulk member; In one cross section along the thickness direction of the substrate, The fiber-shaped conductive member has a maximum height H ｍａｘ having The composite bulk member has a maximum height H from an outer edge of the composite bulk member. ｍａｘ and a central region sandwiched between the peripheral regions on one side and the other side, the peripheral regions occupying an area up to twice the area of ​​the central region on the one side and the other side, At least one of the peripheral regions on one side and the other side has an area occupancy ratio S of the total area of ​​the fibrous conductive member and the dielectric layer in the central region. １１ The total area occupancy ratio S of the fibrous conductive member and the dielectric layer compared to ２１ Capacitors, including those with high

2. In one cross section along the thickness direction of the substrate, The outer peripheral regions on both sides have the area occupancy ratio S １１ Compared to the above, the area occupancy ratio S ２１ The capacitor of claim 1 , further comprising a portion having a high

3. In each of a plurality of cross sections along a thickness direction of the substrate, At least one of the outer peripheral regions on one side and the other side has the area occupancy ratio S １１ Compared to the above, the area occupancy ratio S ２１ The capacitor according to claim 1 or 2, comprising a portion where

4. A conductive substrate; a plurality of fibrous conductive members disposed on the substrate and electrically connected to the substrate; a dielectric layer covering a surface of the fibrous conductive member; a conductive layer covering a surface of the dielectric layer, a plurality of the fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of the fibrous conductive members covered by the dielectric layer and the conductor layer constitute a composite bulk member; In one cross section along the thickness direction of the substrate, The fiber-shaped conductive member has a maximum height H ｍａｘ having The composite bulk member has a maximum height H from an outer edge of the composite bulk member. ｍａｘ and a central region sandwiched between the peripheral regions on one side and the other side, the peripheral regions occupying an area up to twice the area of ​​the central region on the one side and the other side, At least one of the peripheral regions on one side and the other side is a ratio S of the total area occupied by the fiber-shaped conductive member, the dielectric layer and the conductor layer in the central region. １２ The total area occupancy ratio S of the fibrous conductive member, the dielectric layer and the conductor layer compared to ２２ Capacitors, including those with high

5. In one cross section along the thickness direction of the substrate, The outer peripheral regions on both sides have the area occupancy ratio S １２ Compared to the above, the area occupancy ratio S ２２ The capacitor of claim 4 , further comprising a portion having a high

6. In each of a plurality of cross sections along a thickness direction of the substrate, At least one of the outer peripheral regions on one side and the other side has the area occupancy ratio S １２ Compared to the above, the area occupancy ratio S ２２ The capacitor according to claim 4 or 5, comprising a portion where

7. A conductive substrate; a plurality of fibrous conductive members disposed on the substrate and electrically connected to the substrate; a dielectric layer covering a surface of the fibrous conductive member; a conductive layer covering a surface of the dielectric layer, a plurality of the fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of the fibrous conductive members covered by the dielectric layer and the conductor layer constitute a composite bulk member; In one cross section along the thickness direction of the substrate, the fiber-shaped conductive member has a maximum height H ｍａｘ having In one cross section parallel to an in-plane direction of the substrate, The composite bulk member has a maximum height H from an outer edge of the composite bulk member. ｍａｘ a central region surrounded by the peripheral region, the central region having an area up to twice the area of ​​the peripheral region; The peripheral region is a ratio S of the total area occupied by the fibrous conductive member, the dielectric layer and the conductor layer in the central region. １３ The total area occupancy ratio S of the fibrous conductive member, the dielectric layer and the conductor layer compared to ２３ Capacitors, including those with high

8. In one cross section parallel to an in-plane direction of the substrate, In the outer peripheral region, both of the portions on one side and the other side facing each other across the central region have the area occupancy ratio S １３ Compared to the above, the area occupancy ratio S ２３ The capacitor of claim 7 , comprising a portion where

9. In each of a plurality of cross sections parallel to an in-plane direction of the substrate, The peripheral region has the area occupancy ratio S １３ Compared to the above, the area occupancy ratio S ２３ The capacitor according to claim 7 or 8, comprising a portion where

10. The capacitor of claim 1, 4 or 7, wherein the dielectric layer has a thickness of 10 nm or more.

11. The average number density N of the plurality of fibrous conductive members in the outer circumferential region ２ But, 10 ８ book / cm ２ The capacitor according to claim 1, 4 or 7.

12. The capacitor according to claim 1 , 4 or 7 , wherein the average length of the plurality of fibrous conductive members is 50 μm or more.

13. The average number density N of the plurality of fibrous conductive members in the central region １ The average number density N of the plurality of fibrous conductive members in the outer circumferential region ２ Ratio of N ２ / N １ The capacitor of claim 1 , 4 or 7 , wherein is 2 or greater.

14. The capacitor according to claim 1 , 4 or 7 , wherein the fibrous conductive members are carbon nanotubes.

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