Capacitor

Abstract

Provided is a capacitor provided with a composite member having excellent mechanical strength. A capacitor is provided with: a conductive substrate; a plurality of fibrous conductive members disposed on the substrate and electrically connected to the substrate; a dielectric layer covering the surface of the fibrous conductive member; and a conductor layer covering the surface of the dielectric layer, the plurality of fibrous conductive members, the dielectric layer, the conductor layer, and a space formed between the plurality of fibrous conductive members covered by the dielectric layer and the conductor layer constitute a composite member. In one cross-section along the thickness direction of the substrate, the fibrous conductive member has a maximum height Hmax. The composite member has outer peripheral regions on one side and on the other side that occupy a region from the outer edge of the composite member up to twice the maximum height Hmax, and a central region sandwiched between the outer peripheral regions on one side and on the other side. At least one of the outer peripheral regions on one side and the other side includes a portion in which the total area occupancy ratio (S21) of the fibrous conductive member and the dielectric layer is higher than the total area occupancy ratio (S11) of the fibrous conductive member and the dielectric layer in the central region.

Description

Technical Field

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

[0002] In the past, it is known that capacitors can be manufactured using fibrous components. For example, Patent Document 1 describes a method in which a fibrous component is formed on a substrate (base surface), and a lower plate (metal), an insulating layer, and an upper plate (metal) are sequentially formed on the surface thereof, thereby forming a capacitor having a metal-insulator-metal (MIM) structure.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application No. 2010-506391

[0006] Non-patent literature

[0007] 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 elastocapillarydensification", Journal of Micromechanics and Microengineering, 2011. Summary of the invention

[0008] Problem that the invention aims to solve

[0009] When the fibrous member has conductivity, if a dielectric layer is formed on the surface of the fibrous conductive member and a conductor layer is further formed, a capacitor having a conductor-dielectric-conductor structure can be formed.

[0010] As multiple fibrous conductive members, for example, vertically aligned carbon nanotubes (hereinafter also referred to as "VACNT") can be used. VACNT can be grown at a high density on a substrate with a catalyst attached. Usually, multiple adjacent VACNTs are entangled with each other and integrated to form a forest.

[0011] The integrated plurality of VACNTs are covered with dielectric layers and conductive layers to form a composite member, but the mechanical strength thereof is sometimes insufficient. If the composite member is damaged during use of the capacitor, the performance of the capacitor will be reduced.

[0012] An object of the present disclosure is to provide a capacitor including a composite member having excellent mechanical strength.

[0013] Technical solutions to solve problems

[0014] According to the subject matter of the present disclosure, a capacitor can be provided, comprising:

[0015] A substrate, which is electrically conductive;

[0016] a plurality of fibrous conductive members, arranged on the substrate and electrically connected to the substrate;

[0017] a dielectric layer covering the surface of the fibrous conductive member; and

[0018] a conductive layer covering the surface of the dielectric layer,

[0019] The plurality of fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of fibrous conductive members covered with the dielectric layer and the conductor layer constitute a composite member.

[0020] In a cross section along the thickness direction of the substrate,

[0021] The fibrous conductive member has a maximum height H max ,

[0022] The composite member has: a peripheral area on one side and another side, which occupies a distance from the outer edge of the composite member to the maximum height H max and a central region sandwiched by the peripheral regions on one side and the other side,

[0023] The total area occupancy ratio S of the fibrous conductive member and the dielectric layer in at least one of the outer peripheral regions on one side and the other side is 21 The area occupancy ratio S of the total area of ​​the fibrous conductive member and the dielectric layer in the central region is 11 High part.

[0024] According to the subject matter of the present disclosure, a capacitor can be provided, comprising:

[0025] A substrate, which is electrically conductive;

[0026] a plurality of fibrous conductive members, arranged on the substrate and electrically connected to the substrate;

[0027] a dielectric layer covering the surface of the fibrous conductive member; and

[0028] a conductive layer covering the surface of the dielectric layer,

[0029] The plurality of fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of fibrous conductive members covered with the dielectric layer and the conductor layer constitute a composite member.

[0030] In a cross section along the thickness direction of the substrate,

[0031] The fibrous conductive member has a maximum height H max ,

[0032] The composite member has: a peripheral area on one side and another side, which occupies a distance from the outer edge of the composite member to the maximum height H max and a central region sandwiched by the peripheral regions on one side and the other side,

[0033] The total area occupancy ratio S of the fibrous conductive member, the dielectric layer, and the conductor layer in at least one of the outer peripheral regions on one side and the other side is 22 The area occupancy ratio S of the total area of ​​the fibrous conductive member, the dielectric layer, and the conductor layer in the central region is 12 High part.

[0034] According to the subject matter of the present disclosure, a capacitor can be provided, comprising:

[0035] A substrate, which is electrically conductive;

[0036] a plurality of fibrous conductive members, arranged on the substrate and electrically connected to the substrate;

[0037] a dielectric layer covering the surface of the fibrous conductive member; and

[0038] a conductive layer covering the surface of the dielectric layer,

[0039] The plurality of fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of fibrous conductive members covered with the dielectric layer and the conductor layer constitute a composite member.

[0040] In a cross section along the thickness direction of the substrate,

[0041] The fibrous conductive member has a maximum height H max ,

[0042] In a cross section parallel to the in-plane direction of the substrate,

[0043] The composite component has a peripheral region extending from the outer edge of the composite component to the maximum height H max and a central region, surrounded by the peripheral region,

[0044] The total area occupancy ratio S of the outer peripheral region including the fibrous conductive member, the dielectric layer, and the conductor layer is 23 The area occupancy ratio S of the total area of ​​the fibrous conductive member, the dielectric layer, and the conductor layer in the central region is 13 High part.

[0045] Effects of the Invention

[0046] According to the present disclosure, a capacitor including a composite member having excellent mechanical strength can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic cross-sectional view of the capacitor in Embodiment 1 and Embodiment 2 of the present disclosure.

[0048] Figure 2 yes Figure 1 Magnified view of part A.

[0049] Figure 3 It is along Figure 1 A schematic cross-sectional view of the substrate in-plane direction.

[0050] Figure 4 It is a schematic cross-sectional view of a capacitor in Modification 1 of Embodiment 1 and Modification 2 of Embodiment 2 of the present disclosure.

[0051] Figure 5 yes Figure 4 Magnified view of part B.

[0052] Figure 6 It is a schematic cross-sectional view of a capacitor in Embodiment 3 of the present disclosure.

[0053] Figure 7 yes Figure 6 Magnified view of part D.

[0054] Figure 8 It is a schematic cross-sectional view of a portion of a capacitor in Modification 3 of Embodiment 3 of the present disclosure.

[0055] Fig. 9 This is an electron microscope image of the CNT forest having an inclined shape obtained in Production Example 1 and a part of the substrate taken from the side.

[0056] Fig. 10A This is a SEM image of a part of the outer peripheral region of the polished XZ cross section of the composite member obtained in Production Example 1.

[0057] Fig. 10B This is a SEM image of a part of the central region of the polished XZ cross section of the composite member obtained in Production Example 1.

[0058] Fig.11A This is a SEM image of a part of the outer peripheral region of the polished XY cross section of the composite member obtained in Production Example 1.

[0059] Fig. 11B This is a SEM image of a part of the central region of the polished XY cross section of the composite member obtained in Production Example 1. DETAILED DESCRIPTION

[0060] Hereinafter, a capacitor as one embodiment of the present disclosure will be described in detail through the illustrated embodiments. In addition, the drawings include some schematic drawings, and sometimes do not reflect actual dimensions and ratios. The present disclosure is not limited to these embodiments.

[0061] <Implementation method 1>

[0062] Figure 1 This is a schematic cross-sectional view of the capacitor in Embodiment 1. Figure 1 1 shows a cross section along the thickness direction of the substrate 10. Figure 1 , for convenience, the outer shapes of the substrate 10 and the composite member 20 are shown, and the fibrous conductive member 21, the dielectric layer 22, the conductor layer 23, and the space 24 are omitted. Figure 2 yes Figure 1 This is an enlarged view of part A. Figure 2 , a fibrous conductive member 21 is schematically shown which is covered in sequence with a dielectric layer 22 and a conductor layer 23. Figure 2 In FIG. 1 , only a part of the substrate 10 , the fibrous conductive member 21 , the dielectric layer 22 , and the conductor layer 23 are shown. Figure 3 It is along Figure 1 A schematic cross-sectional view of the substrate in-plane direction.

[0063] In the figure, the thickness direction of the substrate 10 is set as the Z direction. The straight line including the center C of the substrate 10 when the capacitor 1 is observed from the Z direction and extending in the Z direction is set as the central axis AX. The center C of the substrate 10 usually exists on the same axis as the center of the capacitor 1. The direction perpendicular to the Z direction of the cross section obtained by cutting the capacitor 1 with a plane including the central axis AX and extending in the Z direction is set as the X direction (also referred to as the width direction in the 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 set as the Y direction (also referred to as the width direction in the YZ cross section).

[0064] The surface obtained by cutting the capacitor 1 with a surface formed by a straight line extending in the X direction and a straight line extending in the Z direction and including the central axis AX is set as an XZ section. The XZ section is an example of a section along the thickness direction of the substrate 10. The surface obtained by cutting the capacitor 1 with a surface formed by a straight line extending in the Y direction and a straight line extending in the Z direction and including the central axis AX is set as a YZ section. The YZ section is another example of a section along the thickness direction of the substrate 10. The surface obtained by cutting the capacitor 1 with a surface formed by a straight line extending in the X direction and a straight line extending in the Y direction is set as an XY section. 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 includes the substrate 10 when the capacitor 1 is observed from the Z direction.

[0065] In an XZ cross section, the X direction is sometimes referred to as 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.

[0066] (structure)

[0067] The capacitor 1 includes: a substrate 10 having conductivity; a plurality of fibrous conductive members 21 arranged 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 include 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 the space 24 formed between the plurality of fibrous conductive members covered by the dielectric layer 22 and the conductor layer 23 constitute the composite member 20. The space 24 may also be filled with a filling material such as a resin. The conductive member will be described later.

[0068] In the capacitor 1 , “on the substrate 10 ” can be defined as the outer surface of the substrate 10 , which is a surface (a surface 10 a described below) parallel to a plane (XY plane) formed by straight lines extending in the X direction and straight lines extending in the Y direction.

[0069] The dielectric layer 22 may cover the portion of the surface 10a of the substrate 10 where the fibrous conductive members 21 are not arranged between the plurality of fibrous conductive members 21, in addition to the surface of the fibrous conductive members 21 (however, excluding the region directly bonded to the substrate 10). The dielectric layer 22 may be formed continuously with the dielectric portion 22a covering the portion of the surface 10a of the substrate 10 where the fibrous conductive members 21 are not arranged outside the plurality of fibrous conductive members 21. However, the composite member 20 does not include the dielectric portion 22a.

[0070] The conductor layer 23 may also cover the dielectric layer 22 between the plurality of fibrous conductive members 21 in addition to the dielectric layer 22 covering the surface of the fibrous conductive member 21. The portion of the conductor layer 23 covering the dielectric layer 22 between the plurality of fibrous conductive members 21 may be understood as a portion defining the bottom of the space 24 (e.g., the bottom of the groove). The conductor layer 23 may also be formed continuously with the conductor portion 23a covering the dielectric portion 22a on the outside of the plurality of fibrous conductive members 21. However, the composite member 20 does not include the conductor portion 23a.

[0071] The fibrous conductive member 21 is directly bonded to the substrate 10. More specifically, the fibrous conductive member 21 is directly in contact with and bonded to the substrate 10. The fibrous conductive member 21 is directly synthesized on the surface 10a of the substrate 10.

[0072] The plurality of fibrous conductive members 21 are conductive (representatively, conductors), and they are electrically connected to the substrate 10 so as to be at the same potential or voltage. Thus, a conductor-dielectric-conductor structure can be 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 a structure corresponding to the so-called MIM structure (metal-insulator-metal structure). The capacitor 1 having such a structure can obtain a large capacitance density by the large specific surface area of ​​the fibrous conductive members 21.

[0073] In the cross section in the thickness direction (here, XZ cross section), the fibrous conductive member 21 has a maximum height H max In the cross section in the thickness direction, the composite member 20 has: one side and the other side of the peripheral region R2, occupying from the outer edge of the composite member 20 in the direction toward the central axis AX to the maximum height H max and a central region R1, which is sandwiched by the peripheral regions R2 on one side and the other side. Hereinafter, as a cross section in the thickness direction, the XZ cross section will be mainly cited for explanation.

[0074] like Figure 2 As shown in the cross section in the thickness direction, the fibrous conductive member 21 in the outer peripheral region R2 is denser than that in the central region R1. Therefore, the total area occupancy ratio S of the fibrous conductive member 21 and the dielectric layer 22 in the outer peripheral region R2 is 21 The total area occupancy ratio S of the fibrous conductive member 21 and the dielectric layer 22 in the central region R1 is 11 High part.

[0075] The so-called outer peripheral region R2 includes an area occupancy ratio S 21 The "high part" refers to the area occupancy ratio S of at least a part of the outer peripheral region R2 of any cross section in the thickness direction. 21 The area occupancy ratio S of a portion of the central region R1 of the cross section in the same thickness direction is 11 It is not necessary that the area occupies a proportion S of the entire cross section in the thickness direction. 21 Specific area occupancy ratio S 11 high.

[0076] The so-called "area occupancy ratio S 21 Specific area occupancy ratio S 11 The area occupancy ratio S is higher than that of the composite member 20 in the outer peripheral region R2. In other words, the space 24 in the outer peripheral region R2 is narrower than the space 24 in the central region R1. Compared with composite members having the same area occupancy ratio, the composite member 20 involved in this embodiment has higher mechanical strength in the outer peripheral region R2. 21 Specific area occupancy ratio S 11 High”, or in other words, “the average number density N2 of the fibrous conductive members 21 existing in the outer peripheral region R2 is higher than the average number density N1 of the fibrous conductive members 21 existing in the central region R1”.

[0077] If the space is reduced, the large specific surface area of ​​the fibrous conductive member 21 is damaged, resulting in a decrease in the volume capacitance density of the capacitor 1 and the performance of the capacitor 1. In the present embodiment, the area occupancy ratio S of only the outer peripheral region R2 is increased. 21 , thereby being able to improve the mechanical strength of the composite member 20 while suppressing the performance degradation of the capacitor 1.

[0078] The so-called "area occupancy ratio S 21 High", which means the area occupies a proportion of S 11 With S 21 The difference is more than 5%. 21 / S 11 ≥1.05.S21 / S 11 It may be 1.2 or more, 2 or more, or 5 or more.

[0079] (Composite component)

[0080] The composite 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 the plurality of conductive fibers 21 covered by the dielectric layer 22 and the conductor layer 23 (hereinafter also referred to as covered conductive fibers 21 ).

[0081] · Method for determining the composite component 20

[0082] The composite member 20 can be determined based on a cross section (eg, XZ cross section) in the thickness direction of the capacitor 1. As described above, the composite member 20 does not include the dielectric portion 22a and the conductor portion 23a, and thus can be determined to exclude these.

[0083] First, any appropriate filling resin is used to fill the space 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.

[0084] The cross section (herein, XZ cross section) of the capacitor 1 in the thickness direction including the center C is exposed by grinding. The obtained XZ cross section (No. 1) is observed by a scanning electron microscope (SEM). In the SEM image of the XZ cross section (No. 1), the substrate 10 and the first component (not shown) including the conductive fiber 21, the dielectric layer 22 (and the dielectric part 22a, if present, the same below), the conductor layer 23 (and the conductor part 23a, if present, the same below) and the filling resin (corresponding to the above-mentioned space 24) arranged on the surface 10a of the substrate 10 can be confirmed. Furthermore, a conductive component may exist.

[0085] The SEM image is processed to identify the conductive fibers 21, the dielectric layer 22, the conductor layer 23, and the filling resin (space 24) in the first member, thereby identifying the conductive members and distinguishing them. Elemental analysis using energy dispersive X-ray analysis (EDX) may also be used for identification.

[0086] In the XZ cross section, the composite member 20 is a substantially quadrilateral. In this SEM image, the conductive fibers 21 near the four corners of the composite member 20 are identified. When performing this identification, the portion of the SEM image including each corner may be enlarged so that the observation field becomes approximately 1 μm×1 μm.

[0087] In this SEM image, the leftmost conductive fiber 21 of the first member, which is closest to the substrate 10 and located on the leftmost side, is determined. Next, the dielectric layer 22 and the conductor layer 23 covering the leftmost conductive fiber 21 are determined. They can exist continuously with the dielectric part 22a and the conductor part 23a, respectively. In terms of the manufacturing method, the thickness of the dielectric layer 22 (and the dielectric part 22a, the same below) covering the conductive fiber 21 is roughly the same. 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. In terms of the manufacturing method, the thickness of the conductor layer 23 (and the conductor part 23a, the same below) covering the conductive fiber 21 through the dielectric layer 22 is also roughly the same. Therefore, the outer edge of the above-mentioned 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.

[0088] A first straight line L1 is drawn that is tangential to the outer edge of the determined conductor layer 23 and parallel to the central axis AX. The first straight line L1 is a straight line that defines the boundary (imaginary boundary, the same below) 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 first straight line L1, the dielectric layer 22 is located on the right side, and the dielectric portion 22a is located on the left side. With respect to the first straight line L1, the conductor layer 23 is located on the right side, and the conductor portion 23a is located on the left side. The above-mentioned dielectric portion 22a and conductor portion 23a are not included in the composite member 20.

[0089] Similarly, the rightmost conductive fiber 21 of the first member which is closest to the substrate 10 and located on the rightmost side is determined, and the dielectric layer 22 and the conductor layer 23 covering the rightmost conductive fiber 21 are determined. A second straight line L2 which is tangent to the outer edge of the conductor layer 23 and parallel to the central axis AX is drawn. The second straight line L2 is a straight line defining 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 side, and the dielectric portion 22a is located on the right side. With respect to the second straight line L2, the conductor layer 23 is located on the left side, and the conductor portion 23a is located on the right side. The above-mentioned dielectric portion 22a and conductor portion 23a are not included in the composite member 20.

[0090] Similarly, when the conductor layer 23 and the conductive member are in contact, the outer edge of the conductor layer 23 can be determined in consideration of the thickness of the conductor layer 23 covering other conductive fibers 21. The conductive member is not included in the composite member 20.

[0091] The composite member 20 is composed of a plurality of conductive fibers 21, a dielectric layer 22, a conductive layer 23, and a space 24 that exist in a region sandwiched by the first straight line L1 and the second straight line L2. The tangent points (T1 and T2) of the first straight line L1 and the second straight line L2 and the composite member 20 are points that show the outer edge of the composite member 20 in the XZ cross section. Typically, the tangent points T1 and T2 are on the surface 10a of the substrate 10.

[0092] Maximum height H max Method of decision

[0093] Maximum height H max For example, it can be determined based on the SEM image of the XZ section (No. 1) described above. The end of the conductive fiber 21 that is farthest from the surface 10a of the substrate 10 in the Z direction is determined, and the distance between the end and the surface 10a in the Z direction is the maximum height H max .

[0094] (Central area R1 and peripheral area R2)

[0095] like Figure 1 As shown, in the XZ cross section, the outer peripheral regions R2 are arranged 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 with the central region R1 sandwiched therebetween. The outer peripheral regions R2 on one side and the other side face each other with the central region R1 sandwiched therebetween.

[0096] · Method for determining the central region R1 and the peripheral region R2

[0097] The outer peripheral region R2 was analyzed using the SEM image of the XZ cross section (No. 1) and the maximum height H max In the SEM image, the maximum height H is depicted from the tangent points T1 and T2 toward the central axis AX (toward the center C when the tangent points T1 and T2 are on the surface 10a of the substrate 10 as shown in the figure). max The area to the left of the third straight line L3 that includes the point P1 and extends in the Z direction is the peripheral area R2 on one side. The area to the right of the fourth straight line L4 that includes the point P2 and extends in the Z direction is the peripheral area R2 on the other side. The area sandwiched by the third straight line L3 and the fourth straight line L4 is the central area R1.

[0098] (Area occupancy ratio S 11 , S 21 )

[0099] Area occupancy ratio S 11The area occupancy ratio S is the total area occupancy ratio of the conductive fiber 21 and the dielectric layer 22 in any part of the central region R1 in the cross section in the thickness direction (for example, the XZ cross section). 21 is the area occupancy ratio of the conductive fiber 21 and the dielectric layer 22 in a portion of the outer peripheral region R2 in the cross section in the same thickness direction as above. Even if the area occupancy ratio S is 21 Specific area occupancy ratio 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 low, 21 Specific area occupancy ratio S 11 High is fine.

[0100] In particular, the area occupancy ratio S of the entire peripheral region R2 in any one cross section in the thickness direction may be 21 Specific area occupancy ratio S 11 high.

[0101] Area occupancy ratio S 11 , S 21 The above relationship can be satisfied only in a portion of a cross section in any thickness direction. Alternatively, in a cross section in any thickness direction, the outer peripheral region R2 on one side and the other side both contain the area occupancy ratio S 21 Specific area occupancy ratio S 11 As a result, the relatively weak central region R1 is protected from both sides, and thus the mechanical strength of the composite member 20 is further improved.

[0102] Alternatively, in a plurality of different cross sections in the thickness direction, the outer peripheral region R2 may include an area occupancy ratio S 21 Specific area occupancy ratio S 11 In this case, the mechanical strength of the composite member 20 is further improved. The so-called "containing ... high parts in multiple thickness direction sections" means that the outer peripheral region R2 in at least two different thickness direction sections contains the area occupancy ratio S 21 Specific area occupancy ratio S 11 It is not necessary that the outer peripheral region R2 includes the area occupancy ratio S in all cross sections in the thickness direction. 21 Specific area occupancy ratio S 11 High part.

[0103] Alternatively, 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 may include the area occupancy ratio S 21 Specific area occupancy ratio S 11High part.

[0104] The different cross sections in the thickness direction are XZ cross sections, and may be YZ cross sections. The different cross sections in the thickness direction can be obtained by rotating the XZ cross section less than 360 degrees around the central axis AX.

[0105] Area occupancy ratio S 11 It may be 0.1 or more, 0.15 or more, or 0.20 or more. 11 It may be 0.5 or less, 0.4 or less, or 0.35 or less.

[0106] Area occupancy ratio S 21 It may be 0.2 or more, 0.25 or more, or 0.30 or more. 21 It may be 0.7 or less, 0.5 or less, or 0.45 or less.

[0107] Area occupancy ratio S 11 , S 21 Calculation method

[0108] Area occupancy ratio S 11 , S 21 The calculation can be performed as follows using the SEM image of the XZ cross section (No. 1). In the SEM image, the composite member 20, the peripheral region R2, and the central region R1 are identified. In the composite member 20, the conductive fibers 21, the dielectric layer 22, the conductive layer 23, and the filling resin (space 24) are distinguished.

[0109] The total area of ​​the conductive fibers 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 of ​​the conductive fibers 21, the dielectric layer 22, the conductor layer 23, and the filling resin). Thus, the area occupancy ratio S of the right peripheral region R2 can be calculated. 21 Similarly, calculate the area occupancy ratio S of the outer peripheral region R2 on the left side. 21 Similarly, the area occupancy ratio S of the central region R1 is calculated. 11 .

[0110] The observation field at this time may be large enough to observe only a portion of the central region R1. Similarly, the observation field may be large enough to observe only a portion of the peripheral region R2. The size of the observation field may be, for example, about 1 μm×1 μm. Thus, it becomes easy to distinguish the conductive fiber 21, the dielectric layer 22, the conductor layer 23, and the filling resin.

[0111] Area occupancy ratio S in multiple cross sections in the thickness direction 11 , S 21 The calculation is as follows. First, for the composite member 20 with the XZ cross section (No. 1) exposed, another cross section in the thickness direction (for example, YZ cross section No. 2) is further exposed by grinding, and its SEM image is observed. Since the maximum height H has been measured, max Next, image processing is performed as described above (EDX analysis is also performed as needed, and the same applies to the following), and the area occupancy ratio S of the peripheral region R2 on one side appearing in the SEM image is calculated. 21 The cross section (No. 2) represents a portion (half) of the cross section in the thickness direction of the composite member 20, but it is not a problem to consider that the remaining portion of the cross section (No. 2) also has the same structure as the portion of the XZ cross section. Therefore, the area occupancy ratio S of the outer peripheral region R2 on the other side is 21 The area occupancy ratio S of the other parts of the central region R1 can also be regarded as the same as that of one side. 11 It can also be considered to be the same as that in the SEM image of the cross section (No. 2). If necessary, repeat this operation for multiple cross sections in different thickness directions. Then, obtain multiple SEM images, perform image processing, etc., and calculate the area occupancy ratio S in the cross sections in multiple thickness directions. 11 , S 21 .

[0112] (other)

[0113] Whether the SEM image of the XZ cross section (No. 1) used in the above is a SEM image of a cross section in the thickness direction of the substrate 10 can be confirmed based on the thickness and width of the observed substrate 10. When the thickness of the substrate 10 measured from the SEM image is greater than the thickness of the original substrate, it can be determined that the cross section is not a cross section in the thickness direction. The so-called "greater than the thickness of the original substrate" means that the thickness of the substrate 10 in the SEM image is greater than the thickness of the original substrate 10 by 5% or more. In addition, when the width of the substrate 10 measured from the SEM image is smaller than the width of the original substrate (the distance between the two intersections of the straight line passing through the center of the substrate and the two ends of the substrate), it can also be determined that the cross section is not a cross section in the thickness direction. The so-called "smaller than the width of the original substrate" means that the width of the substrate 10 in the SEM image is smaller than the width of the original substrate 10 by 5% or more.

[0114] From the perspective of being able to confirm that the above-mentioned SEM image is an SEM image in a cross section in the thickness direction, the observation field of the SEM observation is preferably wide enough to confirm the surface 10a, the back surface 10b, and both ends of the substrate 10 (for example, 5 μm×5 μm or more). On the other hand, the observation field for identifying and / or distinguishing the components of the composite member 20 or calculating the area occupancy ratio may be narrower (for example, about 1 μm×1 μm).

[0115] Hereinafter, each component will be described.

[0116] <<Conductive Fiber>>

[0117] In the present disclosure, the conductive fibers 21 are not particularly limited as long as their longitudinal dimension (length) is (preferably significantly) larger than the maximum dimension of a cross section perpendicular to the longitudinal direction and they are roughly in the shape of elongated lines.

[0118] From the perspective of being able to increase the capacitance density per unit area, the average length of the conductive fiber 21 can be longer. The average length of the conductive fiber 21 can 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 fiber 21 can be appropriately selected, and the length of the conductive fiber 21 can be, for example, less than 10 mm, less than 5 mm, or less than 3 mm. In one embodiment, the average length of the conductive fiber 21 is more than 50 μm. The average length of the conductive fiber 21 can also be more than 50 μm and less than 3 mm.

[0119] The average length of the conductive fibers 21 can be calculated from the SEM image of the XZ cross section (No. 1) described above. The average length of the conductive fibers 21 is an average value of the lengths of at least five conductive fibers 21 .

[0120] From the perspective of increasing the capacitance density per unit area and improving the mechanical strength of the composite member 20, the average number density (also referred to as "average root number density") of the conductive fibers 21 may be larger. The average number density N2 of the conductive fibers 21 in the peripheral region R2 may be 10 8 Root / cm 2 The average number density N2 can be 10 13 Root / cm 2 Below, can also be 10 11 Root / cm 2 Below, can also be 10 10 Root / cm 2 the following.

[0121] In particular, the average length of the conductive fibers 21 may be 50 μm or more, and the average number density N2 in the outer peripheral region R2 may be 10 8 Root / cm 2 As a result, the densely packed conductive fibers 21 in the outer peripheral region R2 are likely to come into contact with other conductive fibers 21, and the mechanical strength of the composite member 20 is likely to be further improved.

[0122] The ratio N2 / N1 of the average number density N2 to the average number density N1 of the plurality of conductive fibers 21 in the central region R1 is, for example, 2 or more. This makes it easy to further improve the mechanical strength of the composite 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.

[0123] ·Calculation method of average number density N1 and N2

[0124] The average number density of the conductive fibers 21 can be used in an area occupation ratio S 11 , S 21 First, the height H of the sample from the surface 10a of the substrate 10 is made the maximum height H by grinding. max The XY cross section at the first position of less than 20% (typically less than 10%) of the composite member 20 is exposed. At this time, the XY cross section in which the dielectric portion 22a or the conductor portion 23a is cut off may be obtained, or the XY cross section in which the dielectric portion 22a or the conductor portion 23a is not cut off may be obtained. Although a portion (which may be less than half) of the XY cross section of the composite member 20 is shown in the obtained XY cross section, it is not a problem to consider that the remaining portion of the XY cross section also has the same structure as the portion of the obtained XY cross section.

[0125] The obtained XY cross section is observed by SEM, and the central region R1 and the peripheral region R2 are determined as follows. Figure 3 As shown, the SEM image shows the outer edge of the composite member 20. However, one side of the outer edge of the composite member 20 in the SEM image is a cutting line CL for exposing the XZ cross section. In the SEM image, the surface 10a of the substrate 10 or the dielectric part 22a or the conductor part 23a covering the surface 10a can be further shown.

[0126] First, as described above, the composite member 20 is divided into the conductive fiber 21, the dielectric layer 22, the conductor layer 23, and the filling resin (space 24) by image processing. Next, in the SEM image, the portion (point) of the plurality of conductive fibers 21 located at the outermost side of the composite member 20 is determined. In the above-mentioned XY cross section, except for the cutting line CL, the outer edge of the composite member 20 can be regarded as similar to the outer edge of the substrate 10. A line is drawn that includes the plurality of points depicted 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 member 20 in the XY cross section.

[0127] Draw a line from any point on the obtained outer edge toward the outer edge opposite to it at the maximum height H calculated. max This operation is repeated for different multiple points (for example, 4 points) on the outer edge, and a line similar to the outer edge of the composite member 20 except for the cutting line CL is drawn, which includes the multiple points drawn. This line is the boundary between the peripheral region R2 and the central region R1. The area from this line to the outer edge of the composite member 20 is the peripheral region R2, and the area inside surrounded by this line and the cutting line CL is the central region R1.

[0128] according to Figure 3 It can be seen that in the composite member 20, the peripheral region R2 is arranged to surround the central region R1. A portion of the outer edge of the composite member 20 is indicated by straight lines L5 and L6. A portion of the boundary between the peripheral region R2 and the central region R1 is indicated by straight lines L7 and L8. Straight lines L5 and L6 correspond to the region including Figure 1 The straight lines L7 and L8 correspond to the straight lines containing the tangent points T1 and T2 in the Y direction. Figure 1 Points P1 and P2 in the straight line along the Y direction.

[0129] 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 find the number of conductive fibers 21 per unit area (number density). This operation is repeated to obtain number densities of five or more fields of view, and the average value thereof is set 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.

[0130] Whether the SEM image of the XY cross section used in the above is a SEM image of a cross section parallel to the in-plane direction of the substrate 10 can be confirmed based on the cross-sectional shape of the conductive fiber 21. At the first position mentioned above, most of the conductive fibers 21 extend in the Z direction, and their cross-sectional shape is roughly circular. Therefore, in the case where 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 so-called "flat cross section of the conductive fiber 21" means that the ratio of the major diameter to the minor diameter (major diameter / minor diameter) of the cross section of the conductive fiber 21 is 1.41 or more. The major diameter is the longest diameter among the diameters passing through the center of the cross section of the conductive fiber 21. The minor diameter is the shortest diameter among the diameters passing 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 includes the cross section of the conductive fiber 21.

[0131] 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.

[0132] The maximum cross-sectional dimension of the conductive fiber 21 can be calculated from the XY cross-sectional SEM image used in calculating 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 conductive fibers 21.

[0133] The conductive fiber 21 may also be a conductive nanofiber (a fiber having a maximum cross-sectional dimension of nanometer order (1 nm or more and less than 1000 nm)). The conductive nanofiber may also be, for example, a conductive nanotube (hollow, preferably cylindrical) or a conductive nanorod (solid, preferably cylindrical). A conductive (including semi-conductive) nanorod is also called a nanowire.

[0134] As the conductive nanofiber that can be used in the present disclosure, for example, carbon nanofiber can be cited. As the conductive nanotube that can be used in the present disclosure, for example, metal nanotubes, organic conductive nanotubes, and inorganic conductive nanotubes can be cited. Typically, the conductive nanotube can be a carbon nanotube or a titanium dioxide carbon nanotube. As the conductive nanorod (nanowire) that can be used in the present disclosure, for example, silicon nanowires, metal nanowires (especially, silver nanowires), and conductive polymer wires can be cited.

[0135] From the perspective of further improving the mechanical strength of the composite member 20, the conductive fiber 21 may have a higher strength than the dielectric layer 22. The strength of the conductive fiber 21 may be 5 MPa / (nm) 2Above and 150Gpa / (nm) 2 As a result, the conductive fiber 21 can function as a core material of the composite member 20, and it can be expected that the occurrence of cracks in the composite member 20 can be suppressed. The strength of the conductive fiber 21 may be 10 MPa / (nm) 2 Above, it can also be 10Gpa / (nm) 2 The strength of the conductive fiber 21 may also be 100 GPa / (nm) 2 the following.

[0136] As a 5Mpa / (nm) 2 Above and 150Gpa / (nm) 2 The conductive fibers 21 having the following strength may be at least one selected from the group consisting of carbon nanotubes, metal nanowires, and conductive polymer wires.

[0137] In particular, the conductive fibers 21 may be carbon nanotubes, which have electrical and thermal conductivity.

[0138] The chirality of the carbon nanotubes is not particularly limited, and they may be either semiconductor or metal, or a mixture of these. From the viewpoint of reducing the resistance value, it is preferred that the ratio of the metal type is high.

[0139] The number of layers of the carbon nanotube is not particularly limited, and may be one layer of SWCNT (single-walled carbon nanotube) or two or more layers of MWCNT (multi-walled carbon nanotube).

[0140] The plurality of conductive fibers 21 may also be so-called vertically aligned carbon nanotubes (VACNT). VACNT has a large specific surface area. In addition, as described later, VACNT can be grown and manufactured in a state of being vertically aligned on the substrate 10, so that the maximum height H can be easily controlled. max Such advantages.

[0141] <<Substrate>>

[0142] The substrate 10 has two main surfaces (the front surface 10 a and the back surface 10 b ) facing each other, and may be in the form of a plate (substrate), foil, film, block, or the like.

[0143] The material constituting the substrate 10 can be appropriately selected as long as it is conductive and can be electrically connected to the plurality of conductive fibers 21. For example, it can be a semiconductor material such as silicon, a conductive material such as a metal (copper, aluminum, nickel), an insulating material (or a relatively low conductive material) such as a ceramic (silicon oxide), or a resin. The substrate 10 can include one material, a mixture of two or more materials, or a composite composed of two or more materials. When the material constituting the substrate 10 is a metal, it is easy to use as a contact with the outside, can reduce the resistance value, and can withstand high temperatures, so it is preferred.

[0144] 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.

[0145] <<Dielectric Layer>>

[0146] The dielectric material constituting the dielectric layer 22 can be appropriately selected. For example, silicon dioxide, aluminum oxide, silicon nitride, tantalum oxide, hafnium oxide, barium titanate, and lead zirconate titanate can be cited. These can be used alone or in combination of two or more (for example, in a stacked form).

[0147] The thickness of the dielectric layer 22 may be greater than 10 nm, or greater than 15 nm. By setting the thickness of the dielectric layer to be greater than 10 nm, the insulation can be improved and the leakage current can be reduced. The thickness of the dielectric layer 22 may be less than 1 μm, or less than 100 nm, or less than 70 nm. By setting the thickness of the dielectric layer 22 to less than 1 μm, a greater electrostatic capacitance can be obtained. In one embodiment, the thickness of the dielectric layer 22 is greater than 10 nm and less than 1 μm.

[0148] The thickness of the dielectric layer 22 can be calculated from the XY cross-sectional SEM image used in the calculation of the average number densities N1 and N2. The thickness of the dielectric layer 22 is the average value of the thickness of the dielectric layer 22 covering at least five or more conductive fibers 21.

[0149] Where present, the material constituting the dielectric portion 22 a and the thickness of the dielectric portion 22 a may be the same as the dielectric layer 22 .

[0150] <<Conductive layer>>

[0151] As the conductive material constituting the conductor layer 23, for example, metals and conductive polymers (polymer materials having conductivity and / or imparted conductivity, also referred to as organic conductive materials) can be cited. These can be used alone or in combination of two or more. The conductor layer 23 can also be a laminate of multiple layers of different conductive materials.

[0152] As metals, silver, gold, copper, platinum, aluminum, or alloys containing at least two of them can be cited. As conductive polymers, PEDOT (polyethylene dioxythiophene), PPy (polypyrrole), PANI (polyaniline), etc. can be cited, and they can be appropriately doped with organic sulfonic acid compounds, such as polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polyacrylic sulfonic acid, polymethacrylic sulfonic acid, poly-2-acrylamide-2-methylpropane sulfonic acid, polyisoprene sulfonic acid, and other dopants.

[0153] The thickness of the conductor layer 23 may be greater than 3 nm, or greater than 10 nm. By setting the thickness of the conductor layer 23 to be greater than 3 nm, the resistance value of the conductor layer 23 itself can be reduced. The thickness of the conductor layer 23 may be less than 500 nm, or less than 100 nm. In one embodiment, the thickness of the conductor layer 23 is greater than 3 nm and less than 500 nm.

[0154] The thickness of the conductor layer 23 can be calculated from the XY cross-sectional SEM image used for calculating the average number densities N1 and N2. The thickness of the conductor layer 23 is the average value of the thickness of the conductor layer 23 covering at least five or more conductive fibers 21.

[0155] When present, the material constituting the conductor portion 23 a and the thickness of the conductor portion 23 a may be the same as those of the conductor layer 23 .

[0156] <<Space>>

[0157] Spaces 24 are formed between the coated conductive fibers 21. By increasing the area occupancy ratio S in the outer peripheral region R1 21 , thereby the space 24 becomes smaller and the mechanical strength of the composite member 20 is improved.

[0158] <<Conductive member>>

[0159] The capacitor 1 may include a conductive member in contact with the conductive layer 23. The conductive member is electrically connected to the conductive layer 23 and plays a role in leading the electrode to the outside of the capacitor 1.

[0160] The conductive member is not in contact with the conductive fiber 21, the dielectric layer 22, and the substrate 10. The boundary between the conductive member and the conductor layer 23 can be confirmed by an SEM image. Alternatively, the boundary between the conductive member and the conductor layer 23 can be determined by elemental analysis using EDX. Furthermore, the boundary between the conductive member and the conductor layer 23 can also be determined based on the thickness of the conductor layer 23 in the portion that is not in contact with the conductive member.

[0161] The conductive member is formed by applying / supplying carbon paste or conductive polymer material to a given surface / portion, for example. Carbon paste and conductive polymer material generally have a relatively high viscosity, so it is difficult to penetrate into the space 24 and difficult to reach the deep part of the space 24 (for example, the surface 10a of the substrate 10). Therefore, the space 24 can be maintained between the coated conductive fibers 21.

[0162] (Manufacturing method)

[0163] The capacitor 1 of the present embodiment can be obtained by, for example, a manufacturing method including the following steps:

[0164] (a) attaching the catalyst to the surface 10 a of the substrate 10 such that the amount of the catalyst attached to the outer edge is greater than that to the central portion;

[0165] (b) growing a plurality of conductive fibers 21 on the surface 10 a of the substrate 10 using the catalyst as a core, thereby preparing a forest consisting of a plurality of conductive fibers 21 directly bonded to the substrate 10 at one end;

[0166] (c) forming the dielectric layer 22 (and the dielectric portion 22a, if present, the same below) covering the surfaces of the plurality of conductive fibers 21 by a sol-gel method; and

[0167] (d) The conductive layer 23 (and the conductive portion 23 a , if present; the same applies hereinafter) covering the surface of the dielectric layer 22 is formed.

[0168] Hereinafter, steps (a) to (d) will be described in more detail.

[0169] Process (a)

[0170] First, a catalyst is attached to the surface 10a of the substrate 10. Vertically aligned carbon nanotubes (VACNT, conductive fibers 21) grow with the catalyst as a core. By attaching the catalyst in a larger amount to the outer edge than to the center of the surface 10a of the substrate 10, a dense portion of VACNT can be provided on the edge of the obtained forest.

[0171] The substrate 10 may also be a synthetic substrate for growing VACNT. Generally, the material of the synthetic substrate is not particularly limited, and for example, silicon oxide, silicon, gallium arsenide, aluminum, SUS, etc. may be used. In this embodiment, a conductive substrate 10 is used as the synthetic substrate.

[0172] As the catalyst, iron, nickel, platinum, cobalt, or alloys containing them can be used. As a method for attaching the catalyst to the substrate 10, chemical vapor deposition (CVD), sputtering, physical vapor deposition (PVD), atomic layer deposition (ALD), etc. can be used, and such a technique can be combined with a technique such as photolithography or etching depending on the situation.

[0173] Process (b)

[0174] Next, a plurality of VACNTs are grown on the surface 10a of the substrate 10 using the catalyst as a nucleus. Thus, a forest consisting of a plurality of VACNTs directly bonded to the substrate 10 at one end can be obtained.

[0175] There is no particular limitation on the method for growing VACNT, and CVD, plasma enhanced CVD, etc. can be used under heating as needed. The gas used is not particularly limited, 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 them and hydrogen and / or ammonia can be used. If desired, moisture can also be present in the surrounding atmosphere when the VACNT is grown. Thus, the VACNT grows on the substrate 10 with the catalyst as the core. The end of the VACNT on the surface 10a side of the substrate 10 is a fixed end fixed to the substrate 10 (generally via a catalyst), and the end on the opposite side of the VACNT is a free end serving as a growth point. The length and diameter of the VACNT can be different depending on parameters such as gas concentration, gas flow rate, temperature, etc. That is, by appropriately selecting these parameters, the length and diameter of the VACNT can be adjusted.

[0176] As a result, a forest of VACNTs can be produced on the substrate 10. Strictly speaking, the length of each VACNT in the obtained forest may deviate on the free end side (for example, in-plane deviation) due to a difference in growth rate, etc. When VACNTs are grown on the substrate 10 to which a catalyst is attached, there may be carbon nanotubes (CNTs) whose growth stops due to catalyst deactivation in the middle of the synthesis of VACNTs. The CNTs that have stopped growing are stretched due to entanglement with the CNTs that continue to grow, so that their fixed ends are separated from the substrate 10 and pulled up toward the front end of the VACNT.

[0177] The plurality of VACNTs (conductive fibers 21 ) obtained as described above are arranged on the substrate 10 , and one end portion is directly bonded to the substrate 10 . However, as can be understood from the above description, some CNTs may not be directly bonded to the substrate 10 .

[0178] Process (c)

[0179] Next, a dielectric layer 22 covering at least the surface of the VACNT is formed by a sol-gel method.

[0180] By appropriately selecting or setting the conditions for implementing the sol-gel method, the thickness of the formed dielectric layer 22 can be controlled. For example, the preparation composition of the liquid used in the sol-gel method, the solvent used in the preparation (for example, water, ethanol, isopropyl alcohol, acetone), the film formation time, the stirring speed, the temperature, etc. can be appropriately selected or set.

[0181] Then, the solvent is removed by drying, thereby forming the dielectric layer 22 .

[0182] Process (d)

[0183] Next, the conductive layer 23 is formed to cover the surface of the dielectric layer 22 .

[0184] The film forming method of the conductor layer 23 is not particularly limited, and a liquid phase film forming method, a vapor phase film forming method, and a combination thereof may be used. The liquid phase film forming method may be, for example, a sol-gel method, plating, etc. The vapor phase film forming method may be ALD, sputtering, CVD, etc.

[0185] For example, the conductor layer 23 can be formed by a liquid phase film forming method using a conductive polymer. More specifically, the conductor layer 23 can be formed by applying / supplying (e.g., coating or dipping) a liquid composition in which the conductive polymer is dissolved or dispersed in an organic solvent to a given surface / portion. The conductive polymer easily penetrates into the space formed between the plurality of VACNTs covered by the dielectric layer 22, and the conductor layer 23 can be appropriately formed even in the deep part (e.g., the bottom) of the space.

[0186] Through the above, it is possible to produce Figure 1 , Figure 2 as well as Figure 3 Capacitor 1 is shown.

[0187] [Modification 1]

[0188] Figure 4 This is a schematic cross-sectional view of a capacitor in Modification 1 of Embodiment 1. Figure 4 is with Figure 1 The corresponding cross section. Figure 5 yes Figure 4 The enlarged view of part B corresponds to Figure 2 .

[0189] In Modification 1, the outer shape of the composite member is different from that of Embodiment 1. This different structure will be described below. The other structures are the same as those of Embodiment 1, and the same reference numerals as those of Embodiment 1 are used and their description is omitted.

[0190] like Figure 4 As shown, in the cross section in the thickness direction (here, the XZ cross section), a portion of the outer edge of the outer peripheral region R2 of the capacitor 1A is inclined toward the X direction. Figure 5 As shown, in the peripheral region R2, the conductive fibers 21 are inclined relative to the Z direction or bent in the X direction. Therefore, the space 24 existing in the peripheral region R2 is compressed and becomes smaller. As a result, the peripheral region R2 becomes the area occupied by the conductive fibers 21 and the dielectric layer 22. 21 The area occupancy ratio S of the conductive fiber 21 and the dielectric layer 22 in the central region R1 is 11 High part.

[0191] In addition, by inclining the conductive fibers 21 relative to the Z direction or bending in the X direction, at least two conductive fibers 21 can contact each other via the dielectric layer 22 or not via the dielectric layer 22 in the peripheral region R2. That is, in the peripheral region R2, the plurality of conductive fibers 21 are located at positions that support each other, so the composite member 20A is not easily deformed by external forces. As a result, the mechanical strength of the composite member 20A is further improved.

[0192] (Manufacturing method)

[0193] The capacitor 1A can be obtained, for example, by a manufacturing method including the following steps:

[0194] (a′) preparing a forest composed of a plurality of VACNTs (conductive fibers 21 ) which are arranged on the surface 10 a of the substrate 10 and directly bonded to the substrate 10 at one end;

[0195] (b') Tilt the VACNTs on the outside of the forest toward the center;

[0196] (c) forming a dielectric layer 22 covering the surfaces of the plurality of VACNTs by a sol-gel method; and

[0197] (d) The conductive layer 23 covering the surface of the dielectric layer 22 is formed.

[0198] Step (b') is described in detail below. Step (a') is performed 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 performed in the same manner as steps (c) and (d) of Embodiment 1.

[0199] Process (b')

[0200] The VACNT at the edge of the obtained forest is tilted toward the center.

[0201] By immersing the forest in a suitable solvent, the VACNTs at the edge of the forest can be tilted toward the center. If the forest is immersed in a suitable solvent, the VACNTs at the outside of the forest become easy to condense with each other. On the other hand, the VACNTs near the center of the forest can easily maintain an upright state. As a result, the VACNTs at the edge tilt toward the center.

[0202] The solvent can be selected in consideration of the wettability of the VACNT. If the wettability of the VACNT is too low, the VACNTs will not easily condense with each other. On the other hand, if the wettability of the VACNT is too high, the VACNTs will excessively condense with each other, and it will be difficult to obtain a composite component 20A suitable for the capacitor 1A. Suitable solvents include, for example, water, ethanol, isopropanol, and acetone. Among them, ethanol is particularly suitable.

[0203] A surfactant may also be added to the solvent. In this way, the wettability of the VACNT can be easily adjusted. The surfactant may also be anionic. The surfactant may be appropriately selected in consideration of the charge and molecular weight of the hydrophilic group. Examples of surfactants include sodium dodecyl sulfate, cetyltrimethylammonium bromide, and sodium dodecylbenzenesulfonate. The amount of surfactant added may be appropriately set in consideration of the wettability of the VACNT.

[0204] The immersion conditions may also be set in consideration of the wettability of the VACNT. From the perspective of being able to suppress excessive aggregation, the immersion may also be performed by placing the substrate 10 provided with the forest 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 the substrate 10 and the liquid surface is approximately 90 degrees.

[0205] The cohesion of forests is also described in Non-Patent Document 1.

[0206] The material of the dielectric layer 22 may also be added to the solvent. Thus, the bath used in step (b') can be used directly to implement step (c). Step (b') and step (c) are implemented simultaneously or continuously in the same bath. In other words, the VACNTs are coagulated with each other and the material of the dielectric layer 22 is attached simultaneously or continuously. The material of the dielectric layer 22 is attached to the surface of the VACNT, thereby making it easy to maintain the proper coagulation state of the VACNTs, and the subsequent drying can inhibit the coagulation from further proceeding. Considering the ease of controlling the coagulation state, steps (b') and steps (c) may also be implemented 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).

[0207] Through the above, it is possible to produce Figure 4 as well as Figure 5 The capacitor shown is 1A.

[0208] <Implementation method 2>

[0209] In the second embodiment, the elements used in calculating the area occupancy ratio are different from those in the first embodiment. Specifically, in addition to the areas of the conductive fibers 21 and the dielectric layer 22, the area of ​​the conductor layer 23 is also used in calculating the area occupancy ratio. The other structures are the same as those in the first embodiment, and the same reference numerals as those in the first embodiment are given and their description is omitted. The second embodiment uses the same elements as those in the first embodiment. Figure 1 to Figure 3 To explain.

[0210] In the second embodiment, the outer peripheral region R2 includes the conductive fibers 21, the dielectric layer 22, and the conductive layer 23, and the total area occupancy ratio S 22 The total area occupancy ratio S of the conductive fiber 21, the dielectric layer 22, and the conductive layer 23 in the central region R1 is 12 High part.

[0211] The so-called "area occupancy ratio S 22 Specific area occupancy ratio S 12In other words, “the space in the outer peripheral region R2 is smaller than the space in the central region R1”. Therefore, compared with a composite member having the same area occupancy ratio, the composite member 20 involved in this embodiment has higher mechanical strength in the outer peripheral region R2. Even in this embodiment, the above-mentioned area occupancy ratio S of only the outer peripheral region R2 can be increased. 22 , thereby improving the mechanical strength of the composite member 20 while suppressing the performance degradation of the capacitor 1.

[0212] The so-called "area occupancy ratio S 22 High", which means that the above area occupancy ratio S 12 With S 22 The difference is more than 5%. 22 / S 12 ≥1.05.S 22 / S 12 It may be 1.2 or more, 2 or more, or 5 or more.

[0213] In S 22 / S 12 ≥1.05, it is considered that the above S 21 / S 11 ≥1.05 is also acceptable. 21 / S 11 ≥1.05, it is considered that S 22 / S 12 A relationship of ≥1.05 is also fine.

[0214] About the area occupancy ratio S 12 , S 22 , can 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 conductor layer 23 is divided by the area of ​​the central region R1 or the peripheral region R2 .

[0215] Area occupancy ratio S 12 It may be 0.10 or more, 0.15 or more, or 0.20 or more. 12 It may be 0.50 or less, 0.40 or less, or 0.35 or less.

[0216] Area occupancy ratio S 22 It may be 0.2 or more, 0.25 or more, or 0.30 or more. 22 It may be 0.70 or less, 0.50 or less, or 0.45 or less.

[0217] [Modification 2]

[0218] In the second modification, the outer shape of the composite member is different from that of the second embodiment. This different structure is the same as the difference between the first embodiment and its first modification. Figure 4 as well as Figure 5 To explain.

[0219] Similar to Modification 1, in the capacitor 1A of Modification 2, in the peripheral region R2 of the XZ cross section, the conductive fiber 21 is inclined relative to the Z direction or bent in the X direction. Therefore, the space 24 existing in the peripheral region R2 is compressed and reduced. The peripheral region R2 includes the conductive fiber 21, the dielectric layer 22, and the conductor layer 23. The total area occupancy ratio S 22 The total area occupancy ratio S of the conductive fiber 21, the dielectric layer 22, and the conductive layer 23 in the central region R1 is 12 High part.

[0220] <Implementation method 3>

[0221] In Embodiment 3, the elements and cross sections used when calculating the area occupation ratio are different from those in Embodiment 1. The following describes the different configuration. The other configurations are the same as those in Embodiment 1, and the same reference numerals as those in Embodiment 1 are used and their descriptions are omitted.

[0222] Figure 6 This is a schematic cross-sectional view of a capacitor in Embodiment 3. Figure 6 FIG. 2 shows a cross section along the in-plane direction of the substrate 10. Figure 6 In FIG. 1 , for convenience, the outer edges of the substrate 10 and the composite member 20B are shown, and the conductive fibers 21 , the dielectric layer 22 , the conductor layer 23 , and the space 24 are omitted. Figure 7 yes Figure 6 This is an enlarged view of part D. Figure 7 , a conductive fiber 21 is schematically shown which is covered in sequence by a dielectric layer 22 and a conductive layer 23. Figure 7 , only a portion of the substrate 10, the conductive fiber 21, the dielectric layer 22, the conductor layer 23, and the space 24 are shown. An example of a cross section of the capacitor in the third embodiment along the thickness direction of the substrate 10 is shown by Figure 1 as well as Figure 2 To express. Figure 7 Corresponds to Figure 2 II section.

[0223] (structure)

[0224] The conductive fibers 21 constituting the composite member 20B have a maximum height H maxIn the XY cross section, the composite member 20B has a maximum height H from the outer edge of the composite member 20B. max An outer peripheral area R2 having a range twice that of the outer peripheral area R2 and a central area R1 surrounded by the outer peripheral area R2.

[0225] like Figure 7 As shown in FIG. 1 , 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 total area occupied by the conductive fibers 21, the dielectric layer 22, and the conductor layer 23 in the outer peripheral region R2 is 1. 23 The total area occupancy ratio S of the conductive fiber 21, the dielectric layer 22, and the conductive layer 23 in the central region R1 is 13 High part.

[0226] The so-called outer peripheral region R2 includes an area occupancy ratio S 23 The "high part" refers to the area occupancy ratio S of at least a part of the outer peripheral region R2 of any XY cross section. 23 The area occupancy ratio S of a portion of the central region R1 in the same XY cross section is 13 It is not necessary that the area occupies a proportion S in the entire XY cross section. 23 Specific area occupancy ratio S 13 high.

[0227] The so-called "area occupancy ratio S 23 Specific area occupancy ratio S 13 In other words, “the space 24 in the outer peripheral region R2 is narrower than the space 24 in the central region R1”. Therefore, the composite member 20B according to the present embodiment has higher mechanical strength in the outer peripheral region R2 than a composite member having the same area occupancy ratio. Even in the present embodiment, the above-mentioned area occupancy ratio S of only the outer peripheral region R2 can be increased. 23 , thereby suppressing the performance degradation of the capacitor 1B and improving the mechanical strength of the composite member 20B. 23 Specific area occupancy ratio S 13 High”, or in other words, “the number density of the conductive fibers 21 existing in the outer peripheral region R2 is higher than the number density of the conductive fibers 21 existing in the central region R1”.

[0228] The so-called "area occupancy ratio S 23 High", which means the area occupies a proportion of S 13 With S 23 The difference is more than 5%. 23 / S 13 ≥1.05.S 23 / S 13It may be 1.2 or more, 2 or more, or 5 or more.

[0229] Area occupancy ratio S 13 The area occupancy ratio S is the total area occupancy ratio of the conductive fiber 21 and the dielectric layer 22 in any part of the central region R1 in any XY cross section. 23 is the area occupancy ratio of the conductive fiber 21 and the dielectric layer 22 in a portion of the outer peripheral region R2 in the same XY cross section as above. 23 Specific area occupancy ratio S 13 Even if the area occupancy ratio S of the other parts of the outer peripheral region R2 in the XY cross section is low, 23 Specific area occupancy ratio S 13 High is fine.

[0230] In particular, the area occupancy ratio S may be 1 in the entire peripheral region R2 of any XY cross section. 23 Specific area occupancy ratio S 13 high.

[0231] Area occupancy ratio S 13 , S 23 The above relationship of suffices as long as it is satisfied in a portion of any one XY cross section. Alternatively, in any one XY cross section, both the one side and the other side of the peripheral region R2 that are opposite to the central region R1 include the area occupancy ratio S 23 Specific area occupancy ratio S 13 As a result, the mechanical strength of the composite member 20B is further improved.

[0232] Alternatively, in a plurality of different XY cross sections, the outer peripheral region R2 may include an area occupancy ratio S 23 Specific area occupancy ratio S 13 In this case, the mechanical strength of the composite member 20B is further improved. The so-called "containing a portion of ...high in multiple XY sections" means that the peripheral region R2 in at least two different XY sections contains an area occupancy ratio S 23 Specific area occupancy ratio S 13 It is not necessary for the outer peripheral region R2 to include the area occupancy ratio S in all XY cross sections. 23 Specific area occupancy ratio S 13 High part.

[0233] In at least two different XY cross sections, two peripheral regions R2 facing each other across the central region R1 may include an area occupancy ratio S 23Specific area occupancy ratio S 13 High part.

[0234] Area occupancy ratio S 13 It may be 0.08 or more, 0.10 or more, or 0.15 or more. 13 It may be 0.50 or less, 0.40 or less, or 0.30 or less.

[0235] Area occupancy ratio S 23 It may be 0.15 or more, 0.20 or more, or 0.25 or more. 23 It may be 0.70 or less, 0.50 or less, or 0.40 or less.

[0236] Maximum height H max Method of decision

[0237] Maximum height H max It can be determined in the same manner as in the first embodiment based on the SEM image of the XZ cross section obtained in the same manner as in the first embodiment.

[0238] (Central area R1 and peripheral area R2)

[0239] In the XY cross section, the outer peripheral region R2 is arranged to surround the central region R1.

[0240] · Method for determining the central region R1 and the peripheral region R2

[0241] The central region R1 and the peripheral region R2 can be used to determine the maximum height H max The sample used in the calculation is determined by the same method as the method for determining the central region R1 and the peripheral region R2 in the first embodiment for calculating the average number densities N1 and N2. Figure 3 In the above sample, the XZ cross section and half of the XY cross section of the capacitor 1B are exposed.

[0242] · Method for determining the opposing peripheral region R2

[0243] The opposite outer peripheral region R2 can also be determined based on the maximum height H max Although a portion (may be less than half) of the XY cross section of the composite member 20B is shown in the XY cross section, it is not a problem to consider that the remaining portion of the XY cross section also has the same structure as the portion of the obtained XY cross section. The XY cross section is schematically shown in Figure 3 . Figure 3 and Figure 6 Correspondingly, in Figure 3 An example of filling the remaining portion of the XY cross section of the composite member 20B removed by cutting is Figure 6 The opposite peripheral region R2 can also be used Figure 6 to decide.

[0244] exist Figure 6 In, with Figure 3 Similarly, straight lines L5 and L6 are shown as part of the outer edge of the composite member 20B, and straight lines L7 and L8 are shown as part of the boundary between the outer peripheral region R2 and the central region R1. Figure 6 , straight lines L9 and L10 are shown as the remaining part of the outer edge of the composite member 20B, and straight lines L11 and L12 are shown as part of the boundary between the outer peripheral region R2 and the central region R1. In the case where the outer edge of the composite member 20B includes a curve, the straight lines L5 and L6 correspond to straight lines that respectively include the left and right ends of the composite member 20B and are along the Y direction. Similarly, the straight lines L9 and L10 correspond to straight lines that respectively include the ends in the Y direction of the composite member 20B and are along the X direction. In the case where 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 respectively include the left and right ends of the central region R1 and are along the Y direction. Similarly, the straight lines L11 and L12 correspond to straight lines that respectively include the ends in the Y direction of the central region R1 and are along the X direction.

[0245] exist Figure 6 In the figure, the opposing peripheral regions R2 can be determined as a combination of "the portion of the peripheral region R2 between the straight lines L5 and L7" and "the portion of the peripheral region R2 between the straight lines L8 and L10", and a combination of "the portion of the peripheral region R2 between the straight lines L9 and L11" and "the portion of the peripheral region R2 between the straight lines L10 and L12".

[0246] (Area occupancy ratio S 13 , S 23 )

[0247] The XY cross section of the sample was observed by SEM. In the SEM image, the composite member 20B, the central region R1, and the peripheral region R2 were identified.

[0248] First, the composite member 20B is divided into the conductive fiber 21, the dielectric layer 22, the conductor layer 23, and the filling 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 of ​​the portion including the conductive fiber 21, the dielectric layer 22, the conductor layer 23, and the filling resin). Thus, the area occupancy ratio S of the peripheral region R2 can be calculated. 23 Similarly, the area occupancy ratio S of the central region R1 is calculated. 13 .

[0249] Area occupancy ratio S in multiple XY cross sections 13 , S 23 The calculation is performed in the same manner as above except that the cutting positions are sequentially changed to the second position, the third position, etc. A plurality of XY cross sections can be obtained from the same sample (capacitor 1B). For example, the first position is set at a maximum height H from the surface 10a of the substrate 10. max Next, the second position is set at a position slightly lower than the first position, and the third position is set at a position lower than the second position. In this way, multiple different XY cross sections can be exposed from the same sample.

[0250] [Variation 3]

[0251] In Modification 3, the outer shape of the composite member is different from that of Embodiment 3. This different structure is the same as the difference between Embodiment 1 and Modification 1 thereof. The other structures are the same as those of Embodiment 1, and the same reference numerals as those of Embodiment 1 are given and their description is omitted.

[0252] Figure 8 This is a schematic cross-sectional view of a portion of a capacitor in a third variation of the third embodiment. Figure 8 1 shows a cross section along the in-plane direction of the substrate 10. An example of a cross section along the in-plane direction of the substrate 10 of the entire capacitor in Modification 3 is shown by Figure 6 To express. Figure 8 and Figure 7 corresponds to Figure 6 An example of a cross section of the capacitor in the third modification along the thickness direction of the substrate 10 is shown in FIG. Figure 4 as well as Figure 5 To express. Figure 8 Corresponds to Figure 5 Section II-II.

[0253] Similar to Modifications 1 and 2, in the capacitor 1C of Modification 3, in the peripheral region R2 of the XZ cross section, the conductive fibers 21 are inclined relative to the Z direction or bent in the X direction. Therefore, the space 24 existing in the peripheral region R2 is covered by the conductive fibers 21 and becomes smaller. As a result, the peripheral region R2 includes the conductive fibers 21, the dielectric layer 22, and the conductor layer 23, and the total area occupancy ratio S is 1 / 2. 23 The total area occupancy ratio S of the conductive fiber 21, the dielectric layer 22, and the conductive layer 23 in the central region R1 is 13 High part.

[0254] Although six embodiments of the present disclosure have been described in detail above, the present disclosure is not limited thereto. For example, any two or more of the features of the above-described embodiments may be combined.

[0255] In the composite member 20, 20A of the above-mentioned embodiment, the conductive fiber 21 is directly bonded to the substrate 10, but the present invention is not limited thereto. The conductive fiber 21 may be bonded to the substrate 10 via a conductive adhesive layer. The conductive fiber 21 may be bonded to the surface of the adhesive layer or to the adhesive layer by inserting its end into the inside of the adhesive layer. Typically, the conductive adhesive layer is formed of a metal material.

[0256] In the composite member 20A of the above-described embodiment, the conductive fibers 21 in the outer peripheral region R2 are in contact with each other via the dielectric layer 22 or without the dielectric layer 22, but the present invention is not limited thereto. The plurality of conductive fibers 21 in the outer peripheral region R2 may be isolated.

[0257] In the XY cross section of the capacitor 1, 1B in the above embodiment, the substrate 10 and the composite member 20, 20B have a quadrilateral shape, but the present invention is not limited thereto. The substrate 10 and the composite member 20, 20B may have a polygonal shape other than a circle, an ellipse, or a quadrilateral.

[0258] In the capacitor 1 , 1A of the above-described embodiment, the conductive fiber 21 and / or the composite member 20 , 20A may be present on a surface (side surface) connecting the front surface 10 a and the back surface 10 b of the substrate 10 .

[0259] In the above-mentioned embodiment, in step (b) or (a′), carbon nanotubes (CNTs) are cited as the conductive fibers 21 , but the present invention is not limited thereto. The conductive fibers 21 may be conductive fibers other than CNTs.

[0260] In the above-mentioned embodiment, in step (b) or (a'), the forest is provided on the substrate 10, but the present invention is not limited thereto. The forest may be provided on another synthetic substrate and then transferred to the substrate 10. In this case, it is sufficient to carry out the steps after the transfer (c) or (b'). An adhesive layer may also be provided on the substrate 10.

[0261] In the above-described embodiment, in step (b′), part of the conductive fibers 21 are tilted by aggregation, but the present invention is not limited thereto. Part of the conductive fibers 21 may be tilted by pressing the forest from the outside toward the center.

[0262] In the above-mentioned embodiment, in step (c), the dielectric layer 22 is formed by a sol-gel method, but the present invention is not limited thereto. The dielectric layer 22 may also be formed by a vapor phase film forming method (typically a sputtering method). In this case, step (c) is performed after removing the solvent used in step (b) or (a'). The dielectric layer 22 may also be formed by a liquid phase film forming method (typically a plating method) other than the sol-gel method. In the case where the dielectric layer 22 contains a metal oxide, a method combining plating and surface oxidation treatment may also be used.

[0263] Example

[0264] The present invention will be described in more detail below with reference to the following production examples, but the present invention is not limited thereto.

[0265] (Production Example 1)

[0266] Capacitors including the composite members according to Modifications 1, 2, and 3 were manufactured.

[0267] (1) Forest Preparation

[0268] A catalyst is applied on the surface of the Si substrate 10 and VACNT is grown, thereby obtaining the forest 200 .

[0269] (2) Tilt of VACNT

[0270] The substrate 10 provided with the forest 200 is immersed in a raw material liquid containing sodium dodecyl sulfate, ammonia and ethanol. The immersion is performed as follows. First, the substrate 10 provided with the forest 200 is placed in the raw material liquid having a liquid temperature of room temperature (23°C ± 3°C) so that the angle between the substrate 10 and the liquid surface of the raw material liquid is approximately 90 degrees. The placing speed is set to 5 mm / sec. Then, the substrate 10 is pulled up and dried.

[0271] The substrate 10 provided with the forest 200 after being immersed in the raw material liquid and dried was observed by an electron microscope. An image of a portion of the substrate 10 having the forest 200 is shown in FIG. Fig. 9 .according to Fig. 9 , it was confirmed that the CNTs at the edge of the forest 200 were tilted toward the center. Fig. 9 In FIG. 1 , for convenience, a dashed line showing the outer edge of the forest 200 and the substrate 10 is marked.

[0272] (3) Formation of dielectric layer

[0273] The dielectric layer 22 is formed on the forest 200. Specifically, the VACNT on the substrate 10 is immersed in a raw material mixture of 3-aminopropyltriethoxysilane and ethanol, and maintained at 25°C for 1.5 hours while stirring at 300 rpm, and then the substrate 10 is pulled up. Finally, it is dried to form a dielectric layer 22 (SiO2) covering the surface of the plurality of CNTs (conductive fibers 21) on the substrate 10.

[0274] (4) Formation of the conductor layer

[0275] Next, the substrate 10 described above was immersed in a dispersion containing PEDOT (polyethylene dioxythiophene) and PSS (polystyrene sulfonic acid) to form the conductor layer 23 (a composite of PEDOT / PSS) on the dielectric layer 22. In this way, a capacitor was obtained.

[0276] After the space in the obtained capacitor composite member was filled with resin, the substrate 10 was observed from the Z direction to determine the center C of the substrate 10. Next, the XZ section including the center C was exposed by grinding. The obtained section was observed by SEM. According to the SEM image, the maximum height H of the CNT max The calculated value is 105 μm. The average length of the fibrous conductive member can be understood to be 50 μm or more.

[0277] In the same SEM image, the area from the outer edge of the composite member to about 200 μm is defined as the outer peripheral region R2, and the rest is defined as the central region R1, and the area occupancy ratio S in the cross section in the thickness direction is calculated as described above. 11 , S 21 And the area occupancy ratio S 12 , S 22 In at least one cross section in the thickness direction, the area occupancy ratio S 22 Satisfied S 22 / S 12≥1.36. In addition, it can be understood that in any cross section in the thickness direction, both the outer peripheral regions R2 on one side and the other side include the area occupancy ratio S 22 The area occupancy ratio S of the central region R1 12 In addition, it can be understood that in any cross section in the thickness direction, both the outer peripheral regions R2 on one side and the other side include the area occupancy ratio S 21 The area occupancy ratio S of the central region R1 11 High part.

[0278] Using a plurality of structures in which a portion of the cross section in the thickness direction is exposed, the area occupation ratio S of the CNT in the XY cross section is calculated as described above. 13 , S 23 In at least one cross section in the in-plane direction, the area occupancy ratio S 23 Satisfied S 23 / S 13 ≥1.53. In addition, it can be understood that in any cross section in the in-plane direction, the outer peripheral region R2 includes the area occupancy ratio S 23 The area occupancy ratio S of the central region R1 13 High part.

[0279] 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 Root / cm 2 The average number density N1 of the conductive fibers 21 in the central region R1 is 2.36×10 9 Root / cm 2 (Ratio N2 / N1=2.24) The maximum cross-sectional dimension of the CNT is 33 nm. The thickness of the dielectric layer 22 is 51 nm. The thickness of the conductor layer 23 is 15 nm.

[0280] Fig. 10A This is a SEM image of a part of the outer peripheral region of the polished XZ cross section of the composite member obtained in Production Example 1. Fig. 10B This is a SEM image of a portion of the central region of the polished XZ cross section of the composite member obtained in Manufacturing Example 1. Fig. 10A as well as Fig. 10B In FIG. 2 , the linear and whitish portions are the conductive fibers 21 covered by the dielectric layer 22 and the conductor layer 23 , and the black portions are the filling resin corresponding to the spaces 24 .

[0281] Fig.11A This is a SEM image of a part of the outer peripheral region of the polished XY cross section of the composite member obtained in Production Example 1. Fig. 11B This is a SEM image of a portion of the central region of the polished XY cross section of the composite member obtained in Manufacturing Example 1. Fig.11A as well as Fig. 11B In FIG. 2 , the circular and whitish portion is the conductive fiber 21 covered by the dielectric layer 22 and the conductor layer 23 , and the black portion is the filling resin corresponding to the space 24 .

[0282] Industrial Applicability

[0283] The capacitor disclosed herein can be used in any appropriate application, and can be preferably used in applications that require a composite member to have high mechanical strength.

[0284] This application claims the priority based on Japanese Patent Application No. 2022-175701 filed in Japan on November 1, 2022, and all the contents described therein are incorporated herein by reference.

[0285] <1>

[0286] A capacitor having:

[0287] A substrate, which is electrically conductive;

[0288] a plurality of fibrous conductive members, arranged on the substrate and electrically connected to the substrate;

[0289] a dielectric layer covering the surface of the fibrous conductive member; and

[0290] a conductive layer covering the surface of the dielectric layer,

[0291] The plurality of fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of fibrous conductive members covered with the dielectric layer and the conductor layer constitute a composite member.

[0292] In a cross section along the thickness direction of the substrate,

[0293] The fibrous conductive member has a maximum height H max ,

[0294] The composite member has: a peripheral area on one side and another side, which occupies a distance from the outer edge of the composite member to the maximum height H max and a central region sandwiched by the peripheral regions on one side and the other side,

[0295] The total area occupancy ratio S of the fibrous conductive member and the dielectric layer in at least one of the outer peripheral regions on one side and the other side is 21The area occupancy ratio S of the total area of ​​the fibrous conductive member and the dielectric layer in the central region is 11 High part.

[0296] <2>

[0297] The capacitor according to <1>, wherein:

[0298] In a cross section along the thickness direction of the substrate,

[0299] The outer peripheral area on one side and the other side both include the area occupancy ratio S 21 The area occupancy ratio S 11 High part.

[0300] <3>

[0301] The capacitor according to <1> or <2>, wherein:

[0302] In each of a plurality of cross sections along the thickness direction of the substrate,

[0303] At least one of the outer peripheral regions on one side and the other side includes the area occupancy ratio S 21 The area occupancy ratio S 11 High part.

[0304] <4>

[0305] A capacitor having:

[0306] A substrate, which is electrically conductive;

[0307] a plurality of fibrous conductive members, arranged on the substrate and electrically connected to the substrate;

[0308] a dielectric layer covering the surface of the fibrous conductive member; and

[0309] a conductive layer covering the surface of the dielectric layer,

[0310] The plurality of fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of fibrous conductive members covered with the dielectric layer and the conductor layer constitute a composite member.

[0311] In a cross section along the thickness direction of the substrate,

[0312] The fibrous conductive member has a maximum height H max ,

[0313] The composite member has: a peripheral area on one side and another side, which occupies a distance from the outer edge of the composite member to the maximum height H max and a central region sandwiched by the peripheral regions on one side and the other side,

[0314] The total area occupancy ratio S of the fibrous conductive member, the dielectric layer, and the conductor layer in at least one of the outer peripheral regions on one side and the other side is 22 The area occupancy ratio S of the total area of ​​the fibrous conductive member, the dielectric layer, and the conductor layer in the central region is 12 High part.

[0315] <5>

[0316] The capacitor according to <4>, wherein:

[0317] In a cross section along the thickness direction of the substrate,

[0318] The outer peripheral area on one side and the other side both include the area occupancy ratio S 22 The area occupancy ratio S 12 High part.

[0319] <6>

[0320] The capacitor according to <4> or <5>, wherein:

[0321] In each of a plurality of cross sections along the thickness direction of the substrate,

[0322] At least one of the outer peripheral regions on one side and the other side includes the area occupancy ratio S 22 The area occupancy ratio S 12 High part.

[0323] <7>

[0324] A capacitor having:

[0325] A substrate, which is electrically conductive;

[0326] a plurality of fibrous conductive members, arranged on the substrate and electrically connected to the substrate;

[0327] a dielectric layer covering the surface of the fibrous conductive member; and

[0328] a conductive layer covering the surface of the dielectric layer,

[0329] The plurality of fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of fibrous conductive members covered with the dielectric layer and the conductor layer constitute a composite member.

[0330] In a cross section along the thickness direction of the substrate,

[0331] The fibrous conductive member has a maximum height H max ,

[0332] In a cross section parallel to the in-plane direction of the substrate,

[0333] The composite component has a peripheral region extending from the outer edge of the composite component to the maximum height H max and a central region, surrounded by the peripheral region,

[0334] The total area occupancy ratio S of the outer peripheral region including the fibrous conductive member, the dielectric layer, and the conductor layer is 23 The area occupancy ratio S of the total area of ​​the fibrous conductive member, the dielectric layer, and the conductor layer in the central region is 13 High part.

[0335] <8>

[0336] The capacitor according to <7>, wherein:

[0337] In a cross section parallel to the in-plane direction of the substrate,

[0338] The area occupancy ratio S is included in both the one side and the other side of the peripheral region that are opposite to the central region. 23 The area occupancy ratio S 13 High part.

[0339] <9>

[0340] The capacitor according to <7> or <8>, wherein:

[0341] In each of a plurality of cross sections parallel to the in-plane direction of the substrate,

[0342] The peripheral region includes the area occupancy ratio S 23 The area occupancy ratio S 13 High part.

[0343] <10>

[0344] The capacitor according to any one of <1> to <9>,

[0345] The thickness of the dielectric layer is greater than 10 nm.

[0346] <11>

[0347] The capacitor according to any one of <1> to <10>,

[0348] The average number density N2 of the plurality of fibrous conductive members in the peripheral region is 10 8 Root / cm 2 above.

[0349] <12>

[0350] The capacitor according to any one of <1> to <11>,

[0351] The average length of the plurality of fibrous conductive members is 50 μm or more.

[0352] <13>

[0353] The capacitor according to any one of <1> to <12>,

[0354] A ratio N2 / N1 of an average number density N2 of the plurality of fibrous conductive members in the outer peripheral region to an average number density N1 of the plurality of fibrous conductive members in the central region is 2 or more.

[0355] <14>

[0356] The capacitor according to any one of <1> to <13>,

[0357] The fibrous conductive member is a carbon nanotube.

[0358] Description of Reference Numerals

[0359] 1, 1A, 1B, 1C: capacitors;

[0360] 10: Substrate;

[0361] 10a: surface;

[0362] 10b: back;

[0363] 20, 20A, 20B: composite components;

[0364] 21: fibrous conductive member (conductive fiber);

[0365] 22: dielectric layer;

[0366] 22a: dielectric part;

[0367] 23: conductor layer;

[0368] 23a: Conductor part;

[0369] 24: Space;

[0370] 200: Forest;

[0371] C: center of substrate;

[0372] AX: central axis;

[0373] R1: Central region;

[0374] R2: peripheral region;

[0375] L1, L2, L5, L6, L9, L10: boundaries between dielectric layers and dielectric parts;

[0376] L3, L4, L7, L8, L11, L12: boundaries between the central region R1 and the peripheral region R2;

[0377] T1: the tangent point between the first straight line L1 and the composite component;

[0378] T2: the tangent point between the second straight line L2 and the composite component;

[0379] P1: From the point of tangency T1 to the center axis AX at the maximum height H max A point that is twice as far away from

[0380] P2: From the tangent point T2 to the center axis AX at the maximum height H max A point that is twice the distance away.

Claims

1. A capacitor having: A substrate, which is electrically conductive; a plurality of fibrous conductive members, arranged on the substrate and electrically connected to the substrate; a dielectric layer covering the surface of the fibrous conductive member; and a conductive layer covering the surface of the dielectric layer, The plurality of fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of fibrous conductive members covered with the dielectric layer and the conductor layer constitute a composite member. In a cross section along the thickness direction of the substrate, The fibrous conductive member has a maximum height H max , The composite member has: a peripheral area on one side and another side, which occupies a distance from the outer edge of the composite member to the maximum height H max and a central region sandwiched by the peripheral regions on one side and the other side, The total area occupancy ratio S of the fibrous conductive member and the dielectric layer in at least one of the outer peripheral regions on one side and the other side is 21 The area occupancy ratio S of the total area of ​​the fibrous conductive member and the dielectric layer in the central region is 11 High part.

2. The capacitor according to claim 1, wherein: In a cross section along the thickness direction of the substrate, The outer peripheral area on one side and the other side both include the area occupancy ratio S 21 The area occupancy ratio S 11 High part.

3. The capacitor according to claim 1 or 2, wherein: In each of a plurality of cross sections along the thickness direction of the substrate, At least one of the outer peripheral regions on one side and the other side includes the area occupancy ratio S 21 The area occupancy ratio S 11 High part.

4. A capacitor having: A substrate, which is electrically conductive; a plurality of fibrous conductive members, arranged on the substrate and electrically connected to the substrate; a dielectric layer covering the surface of the fibrous conductive member; and a conductive layer covering the surface of the dielectric layer, The plurality of fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of fibrous conductive members covered with the dielectric layer and the conductor layer constitute a composite member. In a cross section along the thickness direction of the substrate, The fibrous conductive member has a maximum height H max , The composite member has: a peripheral area on one side and another side, which occupies a distance from the outer edge of the composite member to the maximum height H max and a central region sandwiched by the peripheral regions on one side and the other side, The total area occupancy ratio S of the fibrous conductive member, the dielectric layer, and the conductor layer in at least one of the outer peripheral regions on one side and the other side is 22 The area occupancy ratio S of the total area of ​​the fibrous conductive member, the dielectric layer, and the conductor layer in the central region is 12 High part.

5. The capacitor according to claim 4, wherein: In a cross section along the thickness direction of the substrate, The outer peripheral area on one side and the other side both include the area occupancy ratio S 22 The area occupancy ratio S 12 High part.

6. The capacitor according to claim 4 or 5, wherein: In each of a plurality of cross sections along the thickness direction of the substrate, At least one of the outer peripheral regions on one side and the other side includes the area occupancy ratio S 22 The area occupancy ratio S 12 High part.

7. A capacitor comprising: A substrate, which is electrically conductive; a plurality of fibrous conductive members, arranged on the substrate and electrically connected to the substrate; a dielectric layer covering the surface of the fibrous conductive member; as well as a conductive layer covering the surface of the dielectric layer, The plurality of fibrous conductive members, the dielectric layer, the conductor layer, and spaces formed between the plurality of fibrous conductive members covered with the dielectric layer and the conductor layer constitute a composite member. In a cross section along the thickness direction of the substrate, The fibrous conductive member has a maximum height H max , In a cross section parallel to the in-plane direction of the substrate, The composite component has a peripheral region extending from the outer edge of the composite component to the maximum height H max 2 times the area; and a central region, surrounded by the peripheral region, The total area occupancy ratio S of the outer peripheral region including the fibrous conductive member, the dielectric layer, and the conductor layer is 23 The area occupancy ratio S of the total area of ​​the fibrous conductive member, the dielectric layer, and the conductor layer in the central region is 13 High part.

8. The capacitor according to claim 7, wherein: In a cross section parallel to the in-plane direction of the substrate, The area occupancy ratio S is included in both the one side and the other side of the peripheral region that are opposite to the central region. 23 The area occupancy ratio S 13 High part.

9. The capacitor according to claim 7 or 8, wherein: In each of a plurality of cross sections parallel to the in-plane direction of the substrate, The peripheral region includes the area occupancy ratio S 23 The area occupancy ratio S 13 High part.

10. The capacitor according to any one of claims 1 to 9, wherein: The thickness of the dielectric layer is greater than 10 nm.

11. The capacitor according to any one of claims 1 to 10, wherein: The average number density N2 of the plurality of fibrous conductive members in the peripheral region is 10 8 Root / cm 2 above.

12. The capacitor according to any one of claims 1 to 11, wherein: The average length of the plurality of fibrous conductive members is 50 μm or more.

13. The capacitor according to any one of claims 1 to 12, wherein: A ratio N2 / N1 of an average number density N2 of the plurality of fibrous conductive members in the outer peripheral region to an average number density N1 of the plurality of fibrous conductive members in the central region is 2 or more.

14. The capacitor according to any one of claims 1 to 13, wherein: The fibrous conductive member is a carbon nanotube.

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