JP2004134183A - Electrode sheet and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode sheet to be easily manufactured and provided with a conductive member which hardly falls off from a sheet. <P>SOLUTION: The electrode sheet 10 comprises a sheet-like insulative member 11 and conductive members 12 provided such that the members pass through the insulative member 11 in its thickness direction. The conductive members 12 of the electrode sheet 10 are formed so that regarding their cross-sections parallel to front and back surfaces of the insulative member 11, their cross-sectional areas inward in the thickness direction of the insulative member 11 are larger than those near the front and back surfaces of the insulative member 11. As a result, the conductive members 12 do not fall from the insulative member 11. Then, use of the electrode sheet 10 as an electric connection member in manufacturing semiconductor parts improves reliability in the electric connection. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrode sheet used for an anisotropic conductive bonding member and a method for manufacturing the same.
[0002]
[Prior art]
For example, one of the driving forces that has realized the rapid spread of mobile information devices represented by mobile phones is miniaturization of devices. The technical background for promoting the miniaturization of devices is the progress of System On Chip (abbreviated SOC), which consolidates systems and functions conventionally constituted by a plurality of LSIs (Large Scale Integration) into one semiconductor element. is there. Further, in recent years, a system in which a plurality of semiconductor elements are directly three-dimensionally mounted on a printed circuit board to form one package.
Package (abbreviated SIP) technology has also been put to practical use.
[0003]
As mobile information devices become more sophisticated, the product cycle, that is, the period during which they can be sold as a product that meets the needs of consumers, tends to be shorter. An important issue is to shorten the allowable period before sales start.
[0004]
When the function is changed in the device development, the SOC requires a wide variety of changes from the design of the semiconductor element to the manufacturing process, so that enormous cost and time are required for the development. On the other hand, SIP can respond by changing or adding some types of semiconductor elements, and slightly changing the printed wiring board. Therefore, the development time and cost should be significantly reduced compared to SOC. Is possible.
[0005]
However, even in SIP, there is a problem in miniaturization and high density. In SIP, a plurality of semiconductor elements are collected to constitute one system, and therefore, it is often necessary to mix semiconductor elements having different specifications. In order to realize the miniaturization and high density of the SIP, a method of mounting a bare chip semiconductor element on which a bump or other protruding electrode is arranged on a wiring board in a face-down manner by a flip chip bonding method is preferably used. ing. When a plurality of semiconductor elements having different specifications are used for SIP as described above, if bare chip semiconductor elements having no protruding electrodes are mixed, the flip-chip bonding method cannot be applied. It was a barrier to realization.
[0006]
As a conventional technique for solving such a problem, there is a technique in which electrical bonding is performed using an electrode sheet (also referred to as a conductive sheet), which is an anisotropic conductive bonding member (for example, see Patent Documents 1 and 2). . In the prior art electrode sheet, a plurality of fine holes are formed in an insulating sheet, and the fine holes are filled with a conductive substance such as a metal so as to form bump-shaped projections. It is possible to apply the flip-chip bonding method to the connection of (1).
[0007]
However, simply filling the fine holes formed in the insulating sheet with the conductive material is not enough for the filled conductive material to adhere to the insulating sheet sufficiently, and the conductive material falls off the insulating sheet. In some cases, there is a problem that electrical connection of the semiconductor element cannot be obtained at the dropped portion. In order to solve such a problem, a further conventional technique is to prevent the conductive substance from falling off (for example, see Patent Document 3).
[0008]
FIG. 17 is a cross-sectional view showing a simplified configuration of a conventional electrode sheet 1. The electrode sheet 1 shown in FIG. 17 is disclosed in Patent Document 3. The electrode sheet 1 is configured so that the fine through holes 3 formed in the insulating film 2 are filled with the metal substance 4, and the diameter of the fine through holes 3 is narrow inside. A method for producing such an electrode sheet 1 will be described below.
[0009]
(A1) Fine holes 5a and 5b are formed by half-etching from the front and back sides so as not to penetrate the front and back sides of the insulating film 2 at positions opposite to the front and back sides.
(A2) In the fine holes 5a and 5b, fine through holes 3 having a diameter smaller than the diameters of the fine holes 5a and 5b are formed using, for example, a laser.
(A3) A conductive layer is laminated on the insulating film 2 in which the fine through holes 3 are formed, and a resist layer is formed on the conductive layer surface to insulate the conductive layer surface.
(A4) The through hole is etched to form a groove (recess) having a diameter equal to or less than the diameter of the through hole in the conductive layer portion in contact with the through hole.
(A5) The fine through-hole 3 is filled with a metal substance 4 by a technique such as electrolytic plating or electroless plating, and conduction is obtained between the front and back surfaces of the insulating film 2.
(A6) The entire area of the insulating film 2 is half-etched in the thickness direction to expose the conduction path, and a part of the metal substance 4 is exposed as the bump-shaped metal protrusion 6.
(A7) The conductive layer and the resist layer laminated on the insulating film 2 are removed by a chemical etchant or electrolytic corrosion.
[0010]
The metal sheet 4 is formed by filling the electrode sheet 1 formed in this manner into the fine through-holes 3 formed so as to have a small diameter inside the insulating film 2. Does not fall off the conductive film 2. In addition, since the bump-shaped metal protrusions 6 are formed on the metal material 4, the flip bonding method can be applied to the electrical connection of the semiconductor element.
[0011]
However, the technology disclosed in Patent Document 3 also has the following problems. After once forming fine holes 5a and 5b which do not penetrate from the front and back surfaces of the insulating film 2 by half etching, the fine through holes 3 having a smaller diameter than the fine holes 5a and 5b in the fine holes 5a and 5b. Must be formed. As described above, since the number of manufacturing steps required for high-precision processing increases, there is a problem that productivity is inferior and manufacturing costs cannot be avoided.
[0012]
[Patent Document 1]
JP-A-62-43008 [Patent Document 2]
JP-A-63-40218 [Patent Document 3]
JP-A-5-152019
[Problems to be solved by the invention]
An object of the present invention is to provide an electrode sheet including a conductive member which can be easily manufactured and is hardly dropped from the sheet, and a method for manufacturing the same.
[0014]
[Means for Solving the Problems]
The present invention relates to an electrode sheet including a sheet-shaped insulating member and a conductive member provided to penetrate the insulating member in a thickness direction.
The conductive member,
With respect to a cross section parallel to the front and back surfaces of the insulating member, the insulating member is formed such that a cross-sectional area in the thickness direction inside is larger than a cross-sectional area near the front and back surfaces of the insulating member. Electrode sheet.
[0015]
According to the present invention, the conductive member of the electrode sheet is formed such that the cross-sectional area of the insulating member inward in the thickness direction is larger than the cross-sectional area of the insulating member near the front and back surfaces. Thus, the conductive member can be prevented from falling off from the insulating member, so that the electrical connection reliability of the semiconductor element can be improved.
[0016]
In the present invention, the conductive member,
It is characterized in that it has a shape in which the bottom portions of two substantially truncated cones are brought into contact with each other, and the bottom portion is arranged inside in the thickness direction of the insulating member.
[0017]
In the present invention, the conductive member,
It has a shape in which the bottom portion of one substantially truncated cone and the bottom portion of one substantially column are in contact with each other, and the bottom portion of the substantially truncated cone is arranged inward in the thickness direction of the insulating member. It is characterized by being formed in.
[0018]
According to the present invention, the conductive member has a shape in which the bottom portions of two substantially truncated cones are in contact with each other, such that the bottom portion is disposed inward in the thickness direction of the insulating member, or A bottom surface of one substantially truncated cone and a bottom surface of one substantially column are in contact with each other, such that the bottom of the substantially truncated cone is disposed inward in the thickness direction of the insulating member. It is formed. The shape of such a conductive member is such that, for example, a truncated cone or a columnar space is formed in the insulating member by etching, and the two insulating members formed with these spaces are connected to the bottom portion of the truncated cone. It can be easily formed by sticking so that the bottom part of the competitor or the truncated cone is in contact with the bottom part of the cylinder. The conductive member obtained by filling the formed space with a conductive material is reliably prevented from falling off from the insulating member.
[0019]
Further, the present invention is characterized in that the conductive member is provided with a plating layer facing outward.
[0020]
According to the present invention, the conductive member is provided with a plating layer facing outward. Since the plating layer is formed on the conductive member so as to protrude from the front and back surfaces of the insulating member, the plating layer can serve as a protrusion of the conductive member. This makes it possible to mount the electrode pads of the bare chip semiconductor element on which no protruding electrodes are formed and the electrode pads on the printed wiring board in a face-down manner by a flip chip bonding method.
[0021]
The present invention also includes a step of applying a photoreactive resin on the surface of the metal plate,
A step of locally exposing the photoreactive resin based on a predetermined pattern,
Removing the exposed portion of the photoreactive resin,
Filling a metal space into the void formed by removing the photoreactive resin,
Applying a plating on the surface facing the outside of the filled metal.
[0022]
According to the present invention, there is provided an electrode sheet that can suitably use a flip bonding method for electrical connection of a semiconductor element, the metal sheet being provided so as to penetrate an insulating member made of a photoreactive resin in a thickness direction. It is possible to efficiently manufacture an electrode sheet in which the conductive member does not fall off the insulating member.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a simplified cross-sectional view showing the configuration of an electrode sheet 10 according to an embodiment of the present invention, and FIG. 2 is a partially enlarged view of the electrode sheet 10 shown in FIG. The electrode sheet 10 includes a sheet-shaped insulating member 11 and a conductive member 12 provided to penetrate the insulating member 11 in the thickness direction.
[0024]
The sheet-shaped insulating member 11 is composed of two insulating sheets 11a and 11b, and a photoreactive resin having electrical insulation is preferably used, and has a thickness of, for example, 10 to 100 μm.
[0025]
The conductive member 12 is formed by filling a space formed by penetrating the insulating member 11 in the thickness direction with a metal having excellent conductivity, for example, copper (Cu). The conductive member 12 has a cross section parallel to the front and back surfaces of the insulating member 11 such that the cross sectional area in the thickness direction of the insulating member 11 is larger than the cross sectional area near the front and back surfaces of the insulating member 11. Formed. In the present embodiment, the bottom portions 13 of the two substantially truncated cones have a shape in which the bottom portions 13 are in contact with each other, and the bottom portion 13 is formed so as to be disposed inside the insulating member 11 in the thickness direction. .
[0026]
Further, the conductive member 12 is provided with a plating layer 14 facing outward. In the present embodiment, the plating layer 14 is composed of two layers, the first plating layer 15 provided in contact with the surface of the conductive member 12 is nickel (Ni) plating, and is provided as an outer layer of the first plating layer 15. The second plating layer 16 to be formed is gold (Au) plating.
[0027]
3 to 11 are views schematically showing a method for manufacturing the electrode sheet 10 shown in FIG. A method for manufacturing the electrode sheet 10 will be described with reference to FIGS.
[0028]
In the process shown in FIG. 3, a copper plate 17 having a thickness of, for example, 50 μm is placed on a rotatable table (spinner) (not shown), and an epoxy resin, which is an insulating resin having negative photoreactivity, is coated on the copper plate 17. To form an insulating sheet 11b having a thickness of 5 to 50 μm by centrifugal force generated by rotation of the spinner.
[0029]
In the step shown in FIG. 4, the exposure mask 18 is arranged above the insulating sheet 11b. An opening 19 is formed in the exposure mask 18 at a predetermined position so as to match the position of the bare chip semiconductor element or the electrode pad of the printed wiring board. A light source (not shown) is provided further above the exposure mask 18, emits light from the light source in the direction of the arrow 20 toward the exposure mask 18, performs overexposure with light passing through the opening 19 of the exposure mask 18, A negative photoreaction is generated in the exposed portion of 11b.
[0030]
When the insulating sheet 11b is exposed by the light that has passed through the opening 19 of the exposure mask 18, light is irradiated on the insulating sheet 11b again due to volume reflection of light in the exposed portion. Since the amount of light generated by this volume reflection decreases as going inward in the thickness direction of the insulating sheet 11b, the region where the negative photoreaction is generated in the insulating sheet 11b becomes narrower as going inward in the thickness direction and toward the back surface. Become. Next, the photoreactive resin is cured by a treatment such as heating. At this time, there is no curing in the portion where the negative photoreaction is generated by exposure, and the portion is hardened in the portion where the negative photoreaction is not generated without exposure.
[0031]
In the step shown in FIG. 5, a development process is performed after the curing process to remove the exposed and uncured portions of the photoreactive resin. As described above, the region where the negative photoreaction is generated in the photoreactive resin, that is, the insulating sheet 11b, becomes narrower toward the inner side and the back side in the thickness direction, so that the hole formed by removing the uncured portion is formed. 21 is formed so as to have a substantially frustoconical shape whose diameter is large near the front surface and becomes smaller toward the inside in the thickness direction and toward the rear surface. The hole 21 is preferably formed such that the small diameter that is the diameter of the upper surface portion 22 of the substantially truncated cone is 50 to 100 μm, and the large diameter that is the diameter of the bottom portion 13 of the substantially truncated cone is approximately 100 to 150 μm. . Since the hole 21 is an empty space, the top surface portion 22 and the bottom surface portion 13 do not actually exist, but here, a filler for the hole 21 formed in a substantially truncated cone shape is assumed. It is used in the meaning of the part 22 and the bottom part 13.
[0032]
In the step shown in FIG. 6, another copper plate 17 and the insulating sheet 11a obtained by the same steps up to FIG. 5 are immersed in an etching solution such as a ferric chloride solution to dissolve only the copper plate 17. By removing, only the insulating sheet 11a having the above-mentioned substantially frustoconical hole 21 is obtained. In the step shown in FIG. 7, a member composed of a combination of the copper plate 17 and the insulating sheet 11b shown in FIG. 5 and a sheet of the insulating sheet 11a from which the copper plate 17 is removed shown in FIG. An adhesive or the like is attached so that the assumed bottom portions 13 of the trapezoidal holes 21 are brought into contact with each other. At this time, in order to increase the positioning accuracy of the hole 21, a pin having a diameter approximately equal to the assumed upper surface portion 22 of the hole 21 may be inserted for positioning. FIG. 8 shows a state in which the two insulating sheets 11a and 11b are attached to form the insulating member 11.
[0033]
In the step shown in FIG. 9, the insulating member 11 is charged into a plating tank, and the hole 21 is filled with Cu by performing electrolytic plating of Cu to form the conductive member 12. In this manner, the conductive member 12 has a cross-section parallel to the front and back surfaces of the insulating member 11, and the cross-sectional area of the insulating member 11 inward in the thickness direction is larger than the cross-sectional area of the insulating member 11 near the front and back surfaces. Is also formed to be large.
[0034]
In the step shown in FIG. 10, a mask is applied to the position where the conductive member 12 is provided and the position on the copper plate 17 corresponding to the position where the conductive member 12 is provided, and the resist is applied to portions other than the portion where the mask is applied. 24 is applied. Next, after removing the mask, the first plating layer 15 is formed by performing Ni plating, and the second plating layer 16 is formed by performing Au plating on an outer layer of the first plating layer 15. The first and second plating layers 15 and 16 constitute the plating layer 14. Here, Ni and Au constituting the plating layer 14 are not limited thereto, and the plating layer may be formed of other metals.
[0035]
In the step shown in FIG. 11, the resist 24 is peeled off by chemical etching or electrolytic corrosion. After the resist 24 is peeled off, the copper plate 17 is removed by dipping in an etching solution such as a ferric chloride solution. At this time, since the plating layer 14 having excellent resistance to dissolution in the etching solution functions as a mask, the copper plate 17 and the conductive member 12 corresponding to the lower layer of the plating layer 14 remain without being dissolved. Thus, the above-described electrode sheet 10 shown in FIG. 1 is manufactured.
[0036]
FIG. 12 is a cross-sectional view illustrating one mode of use of the electrode sheet 10, and FIG. 13 is a cross-sectional view illustrating another mode of use of the electrode sheet 10. The electrode sheet 10 is inserted between a bare chip semiconductor element 26 having a plate electrode 25 and a printed wiring board 27. At this time, the bare chip semiconductor element is arranged such that the plating layers 14 provided on the front and back sides of the conductive member 12 of the electrode sheet 10 are in contact with the plate electrode 25 of the bare chip semiconductor element 26 and the electrode 28 of the printed wiring board 27. 26, an electrode sheet 10 and a printed wiring board 27 are arranged. In this state, the flat electrode 25 of the bare chip semiconductor element 26 and the electrode 28 of the printed wiring board 27 are flip-chip connected via the conductive member 12 and the plating layer 14 provided on the front and back sides of the conductive member 12. Bonded by the bonder, it is generated in the semiconductor component 29. The flip chip bonding conditions include, for example, a heating temperature of 250 ° C., a pressing force of 15 kgf / cm ² , and a pressing time of 30 seconds.
[0037]
As described above, since the plating layers 14 provided on the front and back surfaces of the conductive member 12 of the electrode sheet 10 are provided so as to protrude from the front and back surfaces of the electrode sheet 10, bare chip semiconductor elements having no bumps or other protruding electrodes are formed. 26 can be mounted on the printed wiring board 27 in a face-down form by applying the flip chip bonding method.
[0038]
13, in the semiconductor component 29 shown in FIG. 12, a gap formed between the bare chip semiconductor element 26 and the electrode sheet 10 and a gap formed between the printed wiring board 27 and the electrode sheet 10 are It is filled with the resin 30. As described above, since the bare chip semiconductor element 26, the electrode sheet 10 and the printed wiring board 27 are bonded by the resin 30, the reliability of mutual bonding can be improved.
[0039]
FIG. 14 is a simplified cross-sectional view showing a configuration of an electrode sheet 31 according to a second embodiment of the present invention, and FIG. 15 is a view showing one step of a method of manufacturing the electrode sheet 31 shown in FIG. FIG. 16 is a partially enlarged view of the electrode sheet 31 shown in FIG. The electrode sheet 31 of the present embodiment is similar to the electrode sheet 10 of the first embodiment, and corresponding portions are denoted by the same reference numerals and description thereof is omitted.
[0040]
Notable points in the electrode sheet 31 are as follows. An electrode sheet is formed by adhering two insulating sheets, but one of the two insulating sheets is exposed through the opening of the exposure mask to generate a negative photoreaction on the photoreactive resin. Then, the uncured portion exposed after the curing treatment is removed to form the hole 33 formed in the insulating sheet 32 into a columnar shape.
[0041]
In FIG. 15, an assumed bottom portion 34 of a substantially cylindrical shape in a hole 33 formed in the insulating sheet 32 and a assumed bottom portion 13 of a substantially truncated cone formed in the same insulating sheet 11b as in the first embodiment are shown. A step in which the insulating sheet 32 and the insulating sheet 11b are adhered to each other is shown. At this time, the assumed bottom surface portion 13 of a substantially truncated cone is disposed inward in the thickness direction of the insulating member 36 configured by attaching the two insulating sheets 11b and 32. The conductive member 35 is formed by charging the insulating member 36 into the plating tank and performing electrolytic plating to fill the holes 21 and 33 with Cu. Accordingly, the conductive member 35 is also formed such that a cylinder is connected to the bottom surface of the truncated cone.
[0042]
Thereafter, as in the manufacture of the electrode sheet 10 of the first embodiment, a mask is applied to the portion where the conductive member 35 is provided, and a resist is applied to portions other than the portion where the mask is applied. Next, after removing the mask, Ni plating and Au plating are performed to form a plating layer 14. Further, the resist is peeled off by chemical etching or electrolytic corrosion or the like, and immersed in an etching solution to remove the copper plate 17. Thus, the electrode sheet 31 is manufactured. This electrode sheet 31 can also provide the same effect as the electrode sheet 10 of the first embodiment.
[0043]
As described above, in the present embodiment, the insulating member 11 is an epoxy resin, but is not limited thereto, and may be a general thermoplastic or thermosetting resin such as a polyester-based resin or a urethane-based resin. Resins, polystyrene resins, polyethylene resins, polyamide resins, polyimide resins, ABS resins, polycarbonate resins, silicone resins, and the like may be used. When one of these thermoplastic or thermosetting resins is used, the holes 21 and 33 are opened by a drill or a laser.
[0044]
【The invention's effect】
According to the present invention, the conductive member of the electrode sheet is formed such that the cross-sectional area of the insulating member inward in the thickness direction is larger than the cross-sectional area of the insulating member near the front and back surfaces. Thus, the conductive member can be prevented from falling off from the insulating member, so that the electrical connection reliability of the semiconductor element can be improved.
[0045]
Further, according to the present invention, the conductive member has a shape in which the bottom portions of two substantially truncated cones are in contact with each other, and the bottom portion is disposed inward in the thickness direction of the insulating member. Alternatively, it has a shape in which the bottom portion of one substantially truncated cone and the bottom portion of one substantially column are in contact with each other, and the bottom portion of the substantially truncated cone is arranged inward in the thickness direction of the insulating member. Formed. The shape of such a conductive member is such that, for example, a truncated cone or a columnar space is formed in the insulating member by etching, and the two insulating members formed with these spaces are connected to the bottom portion of the truncated cone. It can be easily formed by sticking so that the bottom part of the competitor or the truncated cone is in contact with the bottom part of the cylinder. The conductive member obtained by filling the formed space with a conductive material is reliably prevented from falling off from the insulating member.
[0046]
According to the invention, the conductive member is provided with the plating layer facing outward. Since the plating layer is formed on the conductive member so as to protrude from the front and back surfaces of the insulating member, the plating layer can serve as a protrusion of the conductive member. This makes it possible to mount the electrode pads of the bare chip semiconductor element on which no protruding electrodes are formed and the electrode pads on the printed wiring board in a face-down manner by a flip chip bonding method.
[0047]
Further, according to the present invention, there is provided an electrode sheet that can suitably use a flip bonding method for electrical connection of a semiconductor element, wherein the metal sheet is provided so as to penetrate an insulating member made of a photoreactive resin in a thickness direction. It is possible to efficiently manufacture an electrode sheet that does not cause the conductive member made of aluminum to fall off from the insulating member.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a simplified configuration of an electrode sheet 10 according to an embodiment of the present invention.
FIG. 2 is a partially enlarged view of the electrode sheet 10 shown in FIG.
FIG. 3 is a view schematically showing a method of manufacturing the electrode sheet 10 shown in FIG.
FIG. 4 is a view schematically showing a method of manufacturing the electrode sheet 10 shown in FIG.
FIG. 5 is a view schematically showing a method of manufacturing the electrode sheet 10 shown in FIG.
FIG. 6 is a view schematically showing a method of manufacturing the electrode sheet 10 shown in FIG.
FIG. 7 is a view schematically showing a method of manufacturing the electrode sheet 10 shown in FIG.
FIG. 8 is a view schematically showing a method for manufacturing the electrode sheet 10 shown in FIG.
FIG. 9 is a view schematically showing a method of manufacturing the electrode sheet 10 shown in FIG.
FIG. 10 is a view schematically showing a method for manufacturing the electrode sheet 10 shown in FIG.
FIG. 11 is a view schematically showing a method for manufacturing the electrode sheet 10 shown in FIG.
FIG. 12 is a cross-sectional view showing one mode of use of the electrode sheet 10.
FIG. 13 is a sectional view showing another embodiment of the use of the electrode sheet 10;
FIG. 14 is a simplified cross-sectional view showing a configuration of an electrode sheet 31 according to a second embodiment of the present invention.
FIG. 15 is a view showing one step of a method for manufacturing the electrode sheet 31 shown in FIG.
16 is a partially enlarged view of the electrode sheet 31 shown in FIG.
FIG. 17 is a cross-sectional view showing a simplified configuration of a conventional electrode sheet 1.
[Explanation of symbols]
10, 31 electrode sheet 11, 36 insulating member 12, 35 conductive member 14 plating layer 17 copper plate 21, 33 hole

Claims (5)

In an electrode sheet including a sheet-shaped insulating member and a conductive member provided to penetrate the insulating member in the thickness direction,
The conductive member,
With respect to a cross section parallel to the front and back surfaces of the insulating member, the insulating member is formed such that a cross-sectional area inside the insulating member in the thickness direction is larger than a cross-sectional area near the front and back surfaces of the insulating member. Electrode sheet. The conductive member,
The bottom surface of two substantially truncated cones has a shape formed in contact with each other, and the bottom surface is formed so as to be arranged inward in the thickness direction of the insulating member. The electrode sheet as described above. The conductive member,
It has a shape in which the bottom portion of one substantially truncated cone and the bottom portion of one substantially column are in contact with each other, and the bottom portion of the substantially truncated cone is arranged inward in the thickness direction of the insulating member. The electrode sheet according to claim 1, wherein the electrode sheet is formed. In the conductive member,
The electrode sheet according to any one of claims 1 to 3, wherein a plating layer is provided facing outward. Applying a photoreactive resin on the surface of the metal plate,
A step of locally exposing the photoreactive resin based on a predetermined pattern,
Removing the exposed portion of the photoreactive resin,
A step of filling a metal in a void formed by removing the photoreactive resin,
Applying a plating on a surface facing the outside of the filled metal.

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