conductive film

Abstract

A multilayer wiring substrate (1) includes a first insulator (5) in a sheet shape having a plurality of protrusions (5b) on an upper surface thereof, a first groove portion (7) formed on the upper surface of the first insulator (5), a first metal fine line (13) disposed in the first groove portion (7) along the first groove portion (7), and a second insulator (6) in a sheet shape laminated directly above the first insulator (5), the plurality of protrusions (5b) containing SiO2, the plurality of protrusions (5b) protruding upward into the second insulator (6).

Description

Technical Field

[0001] This disclosure relates to a conductive film. Background Technology

[0002] Patent Document 1 discloses a fine wire structure disposed on a substrate and a touch sensor including the fine wire structure. In the fine wire structure, at least one bottomed groove is disposed on at least one outer surface of the substrate, and a conductive layer made of conductive material is disposed in the groove.

[0003] In addition, Patent Document 1 discloses a fine wire structure in which a first resin layer is formed on the outer surface of a substrate and a plurality of grooves, and a second resin layer is formed on the outer surface of the substrate surrounding each groove (see paragraphs 0048-0050, 0059-0060 of Patent Document 1). Figure 7 ).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2023-179898 Summary of the Invention

[0007] -The technical problem the invention aims to solve-

[0008] In patent document 1 Figure 7 In the structure shown, in which a second resin layer is stacked on top of a first resin layer, there is a need to increase the adhesive force between the two layers.

[0009] This disclosure was made to solve the above-mentioned technical problems, and its purpose is to increase the adhesive force between the sheet-like first insulator on which the first metal wires are arranged and the sheet-like second insulator laminated on the first insulator.

[0010] - Technical solutions used to solve technical problems -

[0011] One embodiment of this disclosure relates to a conductive film. The conductive film includes a first insulator, a first groove, a first metal wire, and a second insulator. The first insulator is sheet-shaped and has a plurality of protrusions on its upper surface. The first groove is formed on the upper surface of the first insulator, and the first metal wire is arranged along the first groove. The second insulator is sheet-shaped and stacked directly above the first insulator. The plurality of protrusions comprise SiO2, protrude upwards, and extend into the second insulator.

[0012] -The effects of the invention-

[0013] According to this disclosure, the adhesive force between the sheet-like first insulator on which the first metal wires are arranged and the sheet-like second insulator stacked on the first insulator can be increased. Attached Figure Description

[0014] Figure 1 This is a perspective view showing a multilayer wiring substrate according to an embodiment of the present disclosure.

[0015] Figure 2 This is a top view showing a multilayer wiring substrate according to an embodiment of the present disclosure.

[0016] Figure 3 It is Figure 2 Part III shows a magnified top view of the area.

[0017] Figure 4 It is Figure 3 The enlarged top view shown in section IV is a partial enlargement.

[0018] Figure 5 It is Figure 4 The V section is shown as a magnified top view.

[0019] Figure 6 It is Figure 4 The enlarged top view shown in section VI is a partial enlargement.

[0020] Figure 7 It is along Figure 5 A sectional view taken along line VII-VII.

[0021] Figure 8 It is along Figure 6 A sectional view taken along line VIII-VIII.

[0022] Figure 9 It is Figure 7 and Figure 8 The enlarged section view shown is a partial enlarged cross-sectional view of part IX.

[0023] Figure 10 This is a cross-sectional view showing a variation of the embodiment involving a first metal wire and a second metal wire.

[0024] Figure 11 This is a cross-sectional view showing the first groove and the second groove involved in a modified embodiment.

[0025] Figure 12 This is an SEM image showing a cross-section near the upper surface of the resin molded body before O2 plasma treatment in the embodiment.

[0026] Figure 13This is a top-view SEM image of the upper surface of the resin molded body in the embodiment.

[0027] Figure 14 This is an SEM image of a cross-section near the upper surface of the resin molded body after O2 plasma treatment in the embodiment.

[0028] Figure 15 yes Figure 14 SEM image of the top surface of the resin molded body in the image, viewed from above. Detailed Implementation

[0029] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. The following description of preferred embodiments is merely illustrative and is not intended to limit the invention, its application, or its uses. It should be noted that the relative dimensions of the parts shown in the drawings may not be the same as the actual relative dimensions.

[0030] (Implementation Method)

[0031] Figure 1 and Figure 2 The overall structure of the multilayer wiring substrate 1 (conductive film) according to an embodiment of the present disclosure is shown. In this embodiment, a multilayer wiring substrate 1 formed by an imprinting process is illustrated. A plurality of mounting elements 2 are disposed on the multilayer wiring substrate 1. Examples of mounting elements 2 include LED elements or diodes. The plurality of mounting elements 2 are arranged above the substrate 3 (described later) in the direction of the upper surface of the first insulator 5 (described later).

[0032] It should be noted that, in this embodiment, for ease of explanation, [the following will be used] Figure 2 The direction from the left side of the paper to the right side is defined as the "X direction". Figure 2 The direction from below the paper to above the paper is defined as the "Y direction".

[0033] ―Substrate―

[0034] like Figure 1 and Figure 2 As shown, the multilayer wiring substrate 1 includes a substrate 3. The substrate 3 is transparent and light-transmitting. It should be noted that, in this embodiment, in the thickness direction of the substrate 3, the side where the thin film substrate 4 is located is defined as the "bottom" of the substrate 3, and the side where the second insulator 6 is located is defined as the "top" of the substrate 3.

[0035] The substrate 3 includes a thin film substrate 4. The thin film substrate 4 is formed of a resin material that is at least flexible and transparent. The thin film substrate 4 preferably has a light transmittance of 80% or more. The thin film substrate 4 is, for example, 25 μm to 200 μm. In addition, the thin film substrate 4 is transparent. Examples of resin materials used as the thin film substrate 4 include PET (polyethylene terephthalate), polycarbonate, COP (cyclic olefin polymer), and COC (cyclic olefin copolymer).

[0036] like Figure 7 and Figure 8 As shown, the substrate 3 includes a sheet-like first insulator 5 and a sheet-like second insulator 6, the first insulator 5 being stacked on top of the thin film substrate 4, and the second insulator 6 being stacked on top of the first insulator 5. The first insulator 5 and the second insulator 6 are respectively composed of a resin material having insulating and light-transmitting properties. This resin material is, for example, a thermosetting resin or a UV-curable resin material. Specifically, the resin material for the first insulator is preferably a solvent-free UV-curable resin. The solvent-free UV-curable resin includes a base resin, a reactive diluent, a photopolymerization initiator, and other additives.

[0037] As the matrix resin, monomers, oligomers, or combinations thereof of (meth)acrylate, polyurethane (meth)acrylate, or epoxy (meth)acrylate are preferred. In particular, in this embodiment, it is preferred to use one or more of the aforementioned monomers or oligomers modified with organosilicon in combination, wherein, more preferably, the aforementioned monomers or oligomers modified with organosilicon are used alone, or combinations thereof. Organosilicon-modified monomers and oligomers are, for example, substances in which a silane coupling agent has been chemically introduced into the polymer. These substances are prepared by reacting the silane coupling agent with the ends or side chains of the polymer, or by copolymerizing the silane coupling agent with the monomer.

[0038] There are no particular limitations on photopolymerization initiators; any initiator can be one that generates free radicals or ions by irradiating with ultraviolet light, thereby initiating the polymerization reaction of monomers or oligomers. Photopolymerization initiators that generate free radicals by irradiating with ultraviolet light are particularly preferred.

[0039] Other additives include antioxidants, surfactants, release agents, fillers, and leveling agents. As reactive diluents, appropriate selections can be made from monofunctional, difunctional, trifunctional, and tetrafunctional or higher polyfunctional (meth)acrylate monomers.

[0040] There are no specific limitations on the specific solvent-free UV-curable resins. Examples include: LUXYDIR (registered trademark) manufactured by DIC Corporation, Elfort (registered trademark) manufactured by Resonac Corporation, Actflow (registered trademark) manufactured by Soken Chemical Co., Ltd., and Ziguang (registered trademark) manufactured by Mitsubishi Chemical Co., Ltd.

[0041] The thickness of the first insulator 5 and the second insulator 6 is, for example, 1 μm to 6 μm. An adhesive portion 5a, described later, is provided between the first insulator 5 and the second insulator 6, which adhesive portion 5a bonds the first insulator 5 and the second insulator 6 together.

[0042] As described later, the upper surface of the first insulator 5 reacts with a silane coupling agent during manufacturing, thus containing Si atoms. On the other hand, the second insulator 6 may or may not contain Si atoms. When the second insulator 6 contains Si atoms, the Si content of the first insulator 5 is greater than the Si content of the second insulator 6.

[0043] A first groove 7 is formed on the upper surface of the first insulator 5, and a first metal wire 13 is arranged along the direction extending from the first groove 7. The groove depth of the first groove 7 is, for example, set to be 0.5 μm or more and 5 μm or less. The first metal wire 13 constitutes the first conductor pattern 10 described later.

[0044] A second groove 8 is formed on the upper surface of the second insulator 6, and a second metal wire 17 is arranged along the direction extending from the second groove 8. The groove depth of the second groove 8 is, for example, set to be 0.5 μm or more and 5 μm or less. The second metal wire 17 constitutes the second conductor pattern 14 described later.

[0045] It should be noted that, as Figure 7 As shown, the bottom of the second groove 8 of the second insulator 6 extends through in the thickness direction, and a conductive portion 22, which will be described later, is formed in this through portion.

[0046] like Figure 9 As shown, the first insulator 5 has a plurality of protrusions 5b located on its upper surface. The protrusions 5b project upwards in a scimitar-like or needle-like shape. A resin material constituting the second insulator 6 is filled between adjacent protrusions 5b. That is, the surface of the protrusions 5b is in contact with the second insulator. In other words, the protrusions 5b enter the second insulator 6. It should be noted that the protrusions 5b only need to project upwards, and their shape is not limited to scimitar-like or needle-like.

[0047] —Adhesive Part—

[0048] The first insulator 5 has an adhesive portion 5a on its upper surface. The adhesive portion 5a has multiple protrusions 5b and flat portions 5c. The first insulator 5 and the second insulator 6 are bonded to each other through chemical or physical bonds of the protrusions 5b. A large adhesive force is applied to the adhesive portion 5a through the anchoring effect of the multiple protrusions 5b.

[0049] The first insulator 5 has a flat portion 5c, in which the polymer of the resin material constituting the first insulator 5 and the polymer of the resin material constituting the second insulator 6 are bonded via atomic groups containing at least Si atoms or via Si atoms. The flat portion 5c can be distributed over the entire surface of the adhesive portion 5a or only a portion of the surface of the adhesive portion 5a. The aforementioned "atomic groups containing at least Si atoms" is, for example, SiO2. That is, in the adhesive portion 5a, at least a portion of the resin material constituting the first insulator 5 becomes a modified polymer containing SiO2 as a molecular backbone. Furthermore, the polymers constituting the first insulator 5 and the second insulator 6 are bonded via covalent bonds through SiO2, thereby firmly bonding the first insulator 5 and the second insulator 6 to each other. In the protrusion 5b, SiO2 can be introduced through treatment using a silane coupling agent and O2 plasma treatment during the manufacturing process described later. Through these treatments, more SiO2 is distributed on the tip side of the protrusion 5b than on the base side. On the base end side of the protrusion 5b, there are fewer covalent bonds via SiO2, and more other bonding mechanisms. "Other bonding mechanisms" include, for example, chemical or physical bonds such as direct or silicon-based covalent bonds between the polymer of the first insulator 5 and the polymer of the second insulator 6.

[0050] —First Conductor Pattern—

[0051] like Figures 1-3 As shown, the multilayer wiring substrate 1 includes a plurality of first conductor patterns 10 formed by first metal wires 13. The plurality of first conductor patterns 10 are arranged with spacing between them in the X direction when viewed from above (equal spacing in the example). It should be noted that... Figures 1-3 In the diagram, for ease of illustration, each first conductor pattern 10 is simplified with dotted shading.

[0052] Each first conductor pattern 10 has a first main body portion 11 and a plurality of (four in the example) first branch portions 12. The first main body portion 11 and each first branch portion 12 are generally strip-shaped when viewed from above. The first main body portion 11 extends in a generally strip-shaped manner along the Y direction when viewed from above. Each first branch portion 12 branches off from the middle portion of the first main body portion 11. Specifically, each first branch portion 12 is configured to extend from the middle portion of the first main body portion 11 in a direction opposite to the X direction (…). Figure 2 and Figure 3 (Extends towards the left side of the paper).

[0053] Each of the first metal wires 13 constituting the first conductor pattern 10 is configured, for example, to have a line width of 15 μm or less. In this embodiment, a cross-section cut perpendicular to the direction in which the first groove 7 extends is ( Figure 7 and Figure 8 On the first insulator 5, the first groove 7 and the first metal wire 13 are generally rectangular in shape. A plurality of first metal wires 13 are arranged in a predetermined pattern on the upper surface of the first insulator 5. Figure 4 As an example of the aforementioned pattern, a grid pattern in which a plurality of first metal wires 13 are arranged in a grid shape is shown.

[0054] The grid pattern (first conductor pattern 10) composed of a plurality of first metal wires 13 is configured such that the plurality of first metal wires 13 intersect each other and are arranged at a predetermined interval (equal interval in the example). Each of the first metal wires 13 constituting the grid pattern extends in a direction inclined relative to both the X and Y directions.

[0055] —Second conductor pattern—

[0056] like Figures 1-3 As shown, the multilayer wiring substrate 1 includes a plurality of second conductor patterns 14. The plurality of second conductor patterns 14 are arranged with spacing between them in the Y direction when viewed from above (equal spacing in the example). It should be noted that... Figures 1-3 In the diagram, for ease of illustration, the second conductor pattern 14 is simplified with dotted shading.

[0057] Each second conductor pattern 14 has a second main body portion 15 and a plurality of (four in the example) second branch portions 16. The second main body portion 15 and each second branch portion 16 are generally strip-shaped when viewed from above. The second main body portion 15 extends in a generally strip-shaped manner along the X direction when viewed from above. Each second branch portion 16 branches off from the middle portion of the second main body portion 15. Specifically, each second branch portion 16 extends from the middle portion of the second main body portion 15 in a direction opposite to the Y direction (…). Figure 2 (Extends below the paper).

[0058] Each of the second metal wires 17 constituting the second conductor pattern 14 is configured, for example, to have a linewidth of 15 μm or less. In this embodiment, on a cross-section cut perpendicular to the direction in which the second groove 8 extends, the second groove 8 and the second metal wires 17 are approximately rectangular in shape. Figure 4 and Figure 5 As shown, a plurality of second metal wires 17 are arranged in a prescribed pattern on the upper surface of the second insulator 6. Figure 4 As an example of the aforementioned pattern, a grid pattern in which multiple second metal wires 17 are arranged in a mesh shape is shown. It should be noted that, in Figure 4In order to distinguish the first metal wire 13 and the second metal wire 17, the second metal wire 17 is represented by a line that is thicker than the first metal wire 13.

[0059] The grid pattern (second conductor pattern 14) composed of a plurality of second metal wires 17 is configured such that the plurality of second metal wires 17 intersect each other and are arranged at a predetermined interval (equal interval in the example). Each of the second metal wires 17 constituting the grid pattern extends in a direction inclined relative to both the X and Y directions.

[0060] —Overlapping Patterns—

[0061] like Figure 3 and Figure 4 As shown, an overlapping pattern 20 is provided on the first conductor pattern 10 and the second conductor pattern 14. The overlapping pattern 20 is configured such that a portion of the first conductor pattern 10 and a portion of the second conductor pattern 14 overlap in the thickness direction of the substrate 3. In this embodiment, the overlapping pattern 20 is configured such that a portion of the first branch 12 and a portion of the second branch 16 overlap in the thickness direction of the substrate 3.

[0062] In the overlapping pattern 20, the spacing between the first metal lines 13, 13 is greater than the spacing between the first metal lines 13, 13 in the first conductor pattern 10 outside the overlapping pattern 20. In this embodiment, the spacing between the first metal lines 13, 13 constituting the overlapping pattern 20 is approximately twice the spacing between the first metal lines 13, 13 in the first conductor pattern 10 outside the overlapping pattern 20. Similarly, the spacing between the second metal lines 17, 17 constituting the overlapping pattern 20 is approximately twice the spacing between the second metal lines 17, 17 in the second conductor pattern 14 outside the overlapping pattern 20.

[0063] In the overlapping pattern 20, when viewed from above, a plurality of first metal lines 13 and a plurality of second metal lines 17 intersect each other. Furthermore, the overlapping pattern 20 is configured such that, when viewed from above, each first metal line 13 and each second metal line 17 is arranged at a predetermined interval (equal intervals in the example shown).

[0064] —Connection Area—

[0065] like Figure 4 and Figure 5 As shown, the overlapping pattern 20 includes a connecting region 21. In the connecting region 21, the first metal wire 13 and the second metal wire 17 are electrically connected. It should be noted that the overlapping pattern 20 of this embodiment includes a connecting region 21. In the connecting region 21, a plurality of first metal wires 13 intersect with a second metal wire 17 (see reference). Figure 5 The intersection point P shown. Figure 5 The connected region 21 shown has 4 intersection points P.

[0066] —Conduction Section—

[0067] like Figure 7 As shown, each of the second metal wires 17 located in the connection region 21 is provided with a conductive portion 22. The conductive portion 22 is arranged in the connection region 21. The conductive portion 22 is made of the same material as each of the second metal wires 17 (the conductive layer 172 described later).

[0068] The conductive portion 22 is integrally formed with the second metal wire 17 located in the connection region 21. In this embodiment, the conductive portion 22 protrudes from the lower part of the second metal wire 17 to a position corresponding to the upper surface of the first insulator 5. The conductive portion 22 is configured such that its line width is less than or equal to the line width of the second metal wire 17.

[0069] The configuration is as follows: at the intersection of the first metal wire 13 and the second metal wire 17 in the connecting region 21 ( Figure 5 At the intersection point P shown, the conductive part 22 is electrically connected to the first metal wire 13. In this embodiment, at the intersection point P, the lower surface of the conductive part 22 contacts the upper surface of the first metal wire 13 located in the connection area 21.

[0070] In this embodiment, the conductive portion 22 is electrically connected to the two first metal wires 13, 13 at two intersection points P, P where the two first metal wires 13, 13 intersect with the second metal wire 17. In this embodiment, the conductive portion 22 and the two first metal wires 13, 13 adjacent to each other in the extension direction of the second metal wire 17 overlap in the thickness direction of the substrate 3 (see reference). Figure 7 ).

[0071] —Imaginary pattern—

[0072] like Figure 3 and Figure 4 As shown, the multilayer wiring substrate 1 includes multiple dummy patterns 30. Figure 3 In the diagram, each of the 30 dummy patterns is simplified using dotted shading. It should be noted that... Figure 1 and Figure 2 The illustrations of each of the dummy patterns 30 are omitted in the text.

[0073] In this embodiment, a plurality of dummy patterns 30 are arranged in the first insulator 5. Specifically, in a top view, the plurality of dummy patterns 30 are arranged in the area of ​​the first insulator 5 where there are no first conductor pattern 10 and second conductor pattern 14 (see reference). Figure 1 and Figure 2 ).

[0074] like Figure 4As shown, the dummy pattern 30 is composed of a plurality of dummy conductive lines 31. Each dummy conductive line 31 is formed as a thin line. Specifically, the linewidth of each dummy conductive line 31 is 15 μm or less.

[0075] A third groove (not shown) is provided on the upper surface of the first insulator 5, and each dummy conductive line 31 is arranged along the direction extending from the third groove. Each dummy conductive line 31 is made of a conductive metal, such as copper, silver, gold, or an alloy containing at least one of these metals. In top view, the third groove is formed in the area of ​​the first insulator 5 where the first conductor pattern 10 is not present. Furthermore, the structure of the third groove is the same as that of the first groove 7. It should be noted that the upper surface of each dummy conductive line 31 may also be formed coplanar with the upper surface of the first insulator 5.

[0076] The plurality of dummy conductive lines 31 are constituted by arranging the plurality of dummy conductive lines 31 into a grid pattern. The grid pattern composed of the plurality of dummy conductive lines 31 has the same structure as the grid pattern composed of the plurality of first metal wires 13.

[0077] Viewed from above, multiple dummy conductive lines 31 and multiple first metal wires 13 are arranged with gaps, forming a first conductor pattern 10 adjacent to each dummy pattern 30. That is, each dummy pattern 30 is in a non-conductive state with respect to the first conductor pattern 10. Furthermore, although not shown, each dummy pattern 30 is insulated from each second conductor pattern 14 by a second insulator 6.

[0078] —Methods for forming protrusions—

[0079] The following describes a method for forming a plurality of protrusions 5b of the first insulator 5. This method is performed during the manufacturing process of the multilayer wiring substrate 1.

[0080] First, as a first step, a resin molded body, which serves as the first insulator 5 and is provided with the first metal wire 13, is prepared. On the upper surface of this resin molded body, the portion in contact with the second insulator 6 is reacted with a silane coupling agent. This introduces silicon groups into the main chain and side chains of the polymer constituting the resin molded body at the portion in contact with the second insulator 6. Examples of silane coupling agents include: A-1110, A-1120, A-2120, and A-1871 manufactured by Momentive Corporation; DOWSIL (registered trademark) Z-6011 Silane, DOWSIL Z-6020 Silane, DOWSIL Z-6094 Silane, and DOWSIL Z-6062 Silane manufactured by DowToray Corporation; and X-40-2761, X-48-5030, and X-48-5031 manufactured by Shin-Etsu Silicones Co., Ltd.

[0081] Next, as a second step, the upper surface of the resin molded body is oxidized by O2 plasma treatment. Regarding the duration of the O2 plasma treatment, for example, when using an RF-based RIE plasma method with a 100W high-frequency output and a Φ200mm electrode, it is preferably 4 minutes or more, more preferably 4.5 minutes or more and 5.5 minutes or less. Through O2 plasma treatment, the silicon-based portions on the upper surface of the resin molded body introduced in the first step are oxidized to glassy SiO2, while other portions (mainly composed of carbon and hydrogen atoms) vaporize and disappear as CO2. As a result, the portions containing unvaporized SiO2 are treated as... Figure 9 The protrusion 5b shown remains in the resin molded body ( Figure 9 The first insulator 5) is located in the center. After O2 plasma treatment, compared with before O2 plasma treatment, the ratio (molar ratio) of Si and O in the main atoms (e.g., C, N, O, Si, P, and S) constituting the upper surface of the resin molded body becomes 2.5 to 3 times. In addition, the protrusion 5b contains SiO2, which is a part that did not vaporize after O2 plasma treatment and remained there. Therefore, the ratio of Si in the atoms constituting the protrusion 5b is higher than the ratio of Si in other parts.

[0082] As described above, a first insulator 5 with protrusions 5b is obtained. Then, resin material for forming a second insulator 6 is poured onto the upper surface of the first insulator 5, and the resin material is cured. Thus, the spaces between adjacent protrusions 5b are also filled with the resin material of the second insulator 6, thereby obtaining... Figure 9 The first insulator 5 and the second insulator 6 are shown in a laminate.

[0083] —Functions and Effects—

[0084] Here, the solvent-free UV-curable resin constituting the first insulator 5 and the second insulator 6 is a resin that does not contain organic solvents but contains reactive diluents. The reactive diluents contain low molecular weight monomers that participate in the polymerization reaction. These low molecular weight monomers replace organic solvents and possess functions such as solubility, wetting, and penetration. However, since the molecular weight of these low molecular weight monomers is larger than that of organic solvents, their penetration is low. Therefore, when the uncured solvent-free UV resin is coated onto the cured first insulator 5 to laminate the second insulator 6, the penetration of the uncured solvent-free UV resin into the first insulator 5 is low, and sometimes sufficient adhesion between the first insulator 5 and the second insulator 6 cannot be achieved. For this reason, when the first insulator 5 and the second insulator 6 are solvent-free UV-curable resins, it is difficult for the layers to adhere tightly, thus there is an urgent need to increase the adhesion between the two layers.

[0085] In this embodiment, the adhesive portion 5a between the first insulator 5 and the second insulator 6 comprises SiO2, thus the first insulator 5 and the second insulator 6 are bonded together by chemical and physical bonds involving SiO2. Furthermore, since the first insulator 5 has multiple protrusions 5b, the adhesive force between the first insulator 5 and the second insulator 6 is further increased by the anchoring effect of the protrusions 5b compared to the case where no protrusions 5b are provided. Based on the above, even when the first insulator 5 and the second insulator 6 are composed of a solvent-free UV-curable resin, the adhesive force between the first insulator 5 and the second insulator 6 can be increased.

[0086] Furthermore, the first insulator 5 and the second insulator 6 are bonded at the bonding portion 5a by chemical bonds involving sites other than SiO2 in the main chain or side chain of the polymer (e.g., silicon-based), resulting in a much stronger adhesive force compared to the absence of such chemical bonds.

[0087] Furthermore, in this embodiment, the first insulator 5 contains Si atoms, the Si content of the first insulator 5 is greater than the Si content of the second insulator 6, and the first insulator 5 is composed of a resin material containing a polymer having a silicon group. This configuration can be obtained by reacting the upper surface of the resin molded body that forms the first insulator 5 with a silane coupling agent. That is, a laminate of the first insulator 5 and the second insulator 6 with strong adhesion can be manufactured, the strong adhesion being generated by the chemical and physical bonds involved by SiO2 as described above.

[0088] The multilayer wiring substrate 1 of this embodiment can be widely used in various technical fields such as touch sensors, liquid crystal display devices, organic light-emitting display devices (OLED), micro LED display devices, solar cell devices, heater devices, antenna devices, and electromagnetic wave shielding sheets.

[0089] (Modifications of the implementation method)

[0090] The first groove 7 and the second groove 8, as well as the first metal wire 13 and the second metal wire 17 arranged in these grooves, can also be configured in place of the above-described embodiment. It should be noted that in the following description, the symbols indicating structures common to the above-described embodiment use the same symbols as in the above-described embodiment.

[0091] —First Metal Wire—

[0092] like Figure 10 and Figure 11As shown, the first metal wire 13 includes conductive material embedded in a first groove 7 formed in the first insulator 5. The first groove 7 is composed of a bottom surface 7a (first bottom surface) extending in the width direction (left-right direction in the figure), a side surface 7b (first side surface) connecting the bottom surface 7a and the opening of the first groove 7, and a corner portion 7c connecting the bottom surface 7a and the side surface 7b. The bottom surface 7a is located below the first metal wire 13. The side surface 7b is located to the side of the first metal wire 13.

[0093] The first metal wire 13 includes an adhesive layer 131 (first adhesive layer) and a conductive layer 132 (first conductive layer). The adhesive layer 131 covers the inner surface of the first groove 7. The conductive layer 132 is disposed along the adhesive layer 131.

[0094] The adhesive layer 131 is an element used to ensure the tightness of the conductive layer 132 relative to the first groove 7. Furthermore, the adhesive layer 131 has low reflectivity. That is, the adhesive layer 131 has the following function: from the side where the first insulator 5 is located ( Figure 10 When observing the multilayer wiring substrate 1 from below the paper, the conductive layer 132 is not easily visually identifiable.

[0095] The bonding layer 131 is a metal layer composed of a metal nitride, a metal oxide, or a metal oxynitride containing both metal nitride and metal oxide. The metal contained therein is, for example, at least one metal selected from the group consisting of Ti, Al, V, W, Ta, Si, Cr, Ag, Mo, Cu, Zn, and Ni. It should be noted that the bonding layer 131 can also be a single layer or a stack of multiple layers with different compositions. The bonding layer 131 is deposited in a thin film form on the first trench 7, for example, by vapor deposition or sputtering.

[0096] The bonding layer 131 includes a bottom portion 131a formed on the bottom surface 7a of the first groove 7 and a side portion 131b formed on the side surface 7b of the first groove 7. The bottom portion 131a and the side portion 131b are connected via a connecting portion 131c formed along the corner 7c of the first groove 7. The first groove 7 has a curved rounded corner at the corner 7c. Specifically, the corner 7c is formed such that the curvature gradually changes from the bottom surface 7a to the side surface 7b. That is, the bottom surface 7a and the side surface 7b are connected at the corner 7c in a manner that the angle changes continuously. Therefore, the bottom surface 7a and the side surface 7b are smoothly connected through the corner 7c. Furthermore, since the connecting portion 131c is formed along the corner 7c of the first groove 7, the bottom portion 131a and the side surface 131b are smoothly connected through the connecting portion 131c. It should be noted that the corner 7c may also be formed with a constant curvature.

[0097] The conductive layer 132 is an element used to ensure the conductivity of the first metal wire 13. The conductive layer 132 is embedded in the first groove 7 in a stacked arrangement close to the adhering layer 131. The conductive layer 132 is made of a conductive metal. For example, copper, silver, gold, or an alloy containing at least one of these metals are preferred as the conductive metal. The conductive layer 132 is formed, for example, by vapor deposition, sputtering, chemical plating, or electroplating. It should be noted that the upper surface of the conductive layer 132 is preferably formed flush with the upper surface of the first insulator 5.

[0098] A blackening layer 133 is formed on the upper surface of the conductive layer 132. The blackening layer 133 has low reflectivity. That is, the blackening layer 133 has the following function: when the multilayer wiring substrate 1 is viewed from the side where the second insulator 6 is located, the conductive layer 132 is not easily visible to the naked eye. The blackening layer 133 is formed, for example, by vapor deposition, sputtering, electroplating or chemical plating.

[0099] In the case where the blackening layer 133 is formed by the above-described electroless plating process, the composition of the electroless plating solution used for the electroless plating process is not particularly limited. For example, if the metal atoms of the conductive layer 132 are copper, an element selected from the group consisting of Pd, Hg, Ag, Ir, Pt, and Au can be used as the atom replacing copper (i.e., the constituent atom of the blackening layer 133). It should be noted that the following description illustrates the case where palladium (Pd) is used as a constituent atom of the blackening layer 133.

[0100] The blackening layer 133 is formed by replacing the grains at the boundaries (so-called "grain boundaries") of the conductive metal constituting the conductive layer 132 on the surface side with palladium (blackening treatment). Specifically, in the blackening treatment, grain boundary etching is performed along the aforementioned grain boundaries to replace the grains of copper or the like constituting the surface layer of the conductive metal with palladium.

[0101] —Second metal wire—

[0102] like Figure 10 and Figure 11 As shown, the second metal wire 17 includes conductive material embedded in a second groove 8 formed in the second insulator 6. The second groove 8 is composed of a bottom surface 8a (second bottom surface) extending in the width direction (left-right direction in the figure), a side surface 8b (second side surface) connecting the bottom surface 8a and the opening of the second groove 8, and a corner portion 8c connecting the bottom surface 8a and the side surface 8b. The bottom surface 8a is located below the second metal wire 17. The side surface 8b is located to the side of the second metal wire 17.

[0103] The second metal wire 17 includes an adhesive layer 171 and a conductive layer 172 (second conductive layer). The adhesive layer 171 covers the inner surface of the second groove 8. The conductive layer 172 is disposed along the adhesive layer 171.

[0104] The adhesive layer 171 is an element used to ensure the tightness of the conductive layer 172 relative to the second groove 8. Furthermore, the adhesive layer 171 has low reflectivity. That is, the adhesive layer 171 has the following function: from the side where the first insulator 5 is located ( Figure 10 When observing the multilayer wiring substrate 1 from below the paper, the conductive layer 172 is not easily visually identifiable.

[0105] The bonding layer 171 is a metal layer composed of a metal nitride, a metal oxide, or a metal oxynitride containing both metal nitride and metal oxide. The metal contained therein is, for example, at least one metal selected from the group consisting of Ti, Al, V, W, Ta, Si, Cr, Ag, Mo, Cu, Zn, and Ni. It should be noted that the bonding layer 171 can also be a single layer or a stack of multiple layers with different compositions. The bonding layer 171 is deposited in a thin film form on the second trench 8, for example, by vapor deposition or sputtering.

[0106] The bonding layer 171 includes a bottom portion 171a formed on the bottom surface 8a of the second groove portion 8 and a side portion 171b formed on the side surface 8b of the second groove portion 8. The bottom portion 171a and the side portion 171b are connected via a connecting portion 171c formed along the corner 8c of the second groove portion 8. The second groove portion 8 has a curved rounded corner at the corner 8c. Specifically, the corner 8c is formed such that the curvature gradually changes from the bottom surface 8a to the side surface 8b. That is, the bottom surface 8a and the side surface 8b are connected at the corner 8c in a manner that the angle changes continuously. Therefore, the bottom surface 8a and the side surface 8b are smoothly connected through the corner 8c. Furthermore, since the connecting portion 171c is formed along the corner 8c of the second groove portion 8, the bottom portion 171a and the side portion 171b are smoothly connected through the connecting portion 171c.

[0107] The conductive layer 172 is an element used to ensure the conductivity of the second metal wire 17. The conductive layer 172 is embedded in the second groove 8 in a stacked arrangement close to the layer 171. The conductive layer 172 is made of a conductive metal. For example, copper, silver, gold, or an alloy containing at least one of these metals are preferred as the conductive metal. The conductive layer 172 is formed, for example, by vapor deposition, sputtering, chemical plating, or electroplating. It should be noted that the upper surface of the conductive layer 172 is preferably formed flush with the upper surface of the second insulator 6.

[0108] A blackening layer 173 is stacked on the upper surface of the conductive layer 172. The blackening layer 173 has low reflectivity. That is, the blackening layer 173 has the following function: when the multilayer wiring substrate 1 is viewed from the side where the second insulator 6 is located, the conductive layer 172 is not easily visible to the naked eye. The blackening layer 173 is formed, for example, by vapor deposition, sputtering, electroplating, or chemical plating.

[0109] In the case where the blackening layer 173 is formed by the above-described electroless plating process, the composition of the electroless plating solution used for the electroless plating process is not particularly limited. For example, if the metal atoms of the conductive layer 172 are copper, an element selected from the group consisting of Pd, Hg, Ag, Ir, Pt, and Au can be used as the atom replacing copper (i.e., the constituent atom of the blackening layer 173). It should be noted that the following description illustrates the case where palladium (Pd) is used as a constituent atom of the blackening layer 173.

[0110] The blackening layer 173 is formed by replacing the grains at the boundaries (so-called "grain boundaries") between the surface-side grains of the conductive metal constituting the conductive layer 172 with palladium (blackening treatment). Specifically, in the blackening treatment, grain boundary etching is performed along the aforementioned grain boundaries to replace the grains of copper or the like constituting the surface layer of the conductive metal with palladium.

[0111] like Figure 11 As shown, the width of the first groove 7, where the first metal wire 13 is embedded, is defined as groove width W1 (first groove width), and the width of the second groove 8, where the second metal wire 17 is embedded, is defined as groove width W2 (second groove width). Therefore, groove width W2 is greater than groove width W1. The angle formed by the bottom surface 7a and the side surface 7b of the first groove 7 is defined as angle D1 (first angle), and the angle formed by the bottom surface 8a and the side surface 8b of the second groove 8 is defined as angle D2 (second angle). Therefore, angle D2 is greater than angle D1.

[0112] This configuration makes it easy to make the cross-sectional area of ​​the second metal wire 17 larger than that of the first metal wire 13. Therefore, based on the inverse relationship between the resistance of a conductor and its cross-sectional area, it is easier to reduce the wiring resistance of the second metal wire 17.

[0113] like Figure 10 As shown, the thickness of the bonding layer 131 on the first bottom surface 7a of the first metal wire 13 is set as thickness L11, and the thickness of the bonding layer 171 on the second bottom surface 8a of the second metal wire 17 is set as thickness L21. Then, the thickness L21 is greater than the thickness L11.

[0114] By increasing the thickness of the bonding layer 171 in this way, the second metal wire 17 becomes less visually identifiable when the multilayer wiring substrate 1 is viewed from below.

[0115] It should be noted that the thickness of the bonding layer 131 can be constant or, as... Figure 10As shown, the thickness L11 on the bottom surface 7a is greater than the thickness L12 near the side surface 7b. In this case, the thickness of the adhesive layer 131 near the corner 8c is formed such that the thickness gradually changes from the bottom surface 8a to the side surface 8b. Furthermore, as described above, the bottom surface 7a and the side surface 7b of the first groove 7 are connected at the corner 7c in a manner that changes angle continuously. With this configuration, at the connection portion 131c connecting the bottom portion 131a and the side portion 131b of the adhesive layer 131, abrupt changes in light reflection can be suppressed, thus making the first metal wire 13 less visually identifiable.

[0116] Similarly, the thickness of the bonding layer 171 can be constant or, as... Figure 10 As shown, the thickness L21 on the bottom surface 8a is greater than the thickness L22 near the side surface 8b. In this case, the thickness of the adhesive layer 171 near the corner 7c is formed to gradually change from the bottom surface 8a to the side surface 8b. Furthermore, as described above, the bottom surface 8a and the side surface 8b of the second groove 8 are connected at the corner 8c in a manner that changes angle continuously. With this configuration, at the connection portion 171c connecting the bottom portion 171a and the side portion 171b of the adhesive layer 171, abrupt changes in light reflection can be suppressed, thus making the second metal wire 17 less visually identifiable.

[0117] The thickness of the blackening layer 133 in the first metal wire 13 is set as thickness L13, and the thickness of the blackening layer 173 in the second metal wire 17 is set as thickness L23. Then, the thickness L13 is greater than the thickness L23.

[0118] Therefore, the thickness L23 of the blackening layer 173 of the second metal wire 17 is relatively small, which improves the connection stability when the second metal wire 17 is connected to the external wiring, and also achieves rust prevention and reduced visual visibility of the second metal wire 17. On the other hand, since the thickness L13 of the blackening layer 133 of the first metal wire 13 is relatively large, the first metal wire 13 and the second metal wire 17 are easily electrically connected through the blackening layer 133, thus improving the connection stability between the first metal wire 13 and the second metal wire 17.

[0119] (Other implementation methods)

[0120] The conductive film disclosed herein is not limited to the embodiments described above, and various modifications can be made within the scope of this disclosure. For example, the conductive film may not include the thin film substrate 4 and the second metal wire 17 (second conductive pattern 10). The first insulator 5 and the second insulator 6 of the substrate 3 may also not be transparent.

[0121] In the above embodiments, each first conductor pattern 10 is shown as being constructed by arranging a plurality of first metal wires 13 into a grid pattern, but is not limited to this method. Similarly, each second conductor pattern 14 is not limited to being constructed by arranging a plurality of second metal wires 17 into a grid pattern.

[0122] In the above embodiment, a method of arranging each dummy pattern 30 in the first insulator 5 is shown, but the method is not limited to this. That is, each dummy pattern 30 may also be arranged in the second insulator 6.

[0123] In the above embodiments, the first insulator 5 and the second insulator 6 are both solvent-free UV-curable resins. However, as long as the first insulator 5 and the second insulator 6 can be stacked on each other, they can also be made of resins other than solvent-free UV-curable resins.

[0124] Example

[0125] The following describes an example of the "method for forming the protrusion" in the above embodiments.

[0126] First, as a first step, a resin molded body made of acrylic resin, which will serve as the first insulator, is prepared. The upper surface of this resin molded body is then reacted with a silane coupling agent. The silane coupling agent used is A-1110 manufactured by Momentive Corporation. As a result, silicone groups are introduced into the main chain and side chains of the acrylic resin constituting the resin molded body, thus creating a silicone-modified acrylic resin. An SEM image of the upper surface of the silicone-modified acrylic resin molded body is shown below. Figure 12 and Figure 13 As shown.

[0127] Next, as a second step, the upper surface of the resin molded body was subjected to O2 plasma treatment for 5 minutes. This caused partial vaporization of the upper surface area of ​​the resin molded body. The SEM image of the upper surface of the resin molded body after partial vaporization is shown below. Figure 14 and Figure 15 As shown.

[0128] and Figure 12 and Figure 13 Compared to before O2 plasma treatment, the difference shown is that... Figure 14 and Figure 15 The ratio (molar ratio) of the main atoms constituting the upper surface of the resin molded body after O2 plasma treatment changes as shown in Table 1. It should be noted that the atomic ratios shown in Table 1 were determined by surface elemental analysis of the upper surface of the resin molded body using X-ray photoelectron spectroscopy (XPS).

[0129] [Table 1]

[0130]

[0131] As shown in Table 1, by performing O2 plasma treatment, the ratio of Si atoms increased to about 3 times and the ratio of O atoms increased to about 2.6 times.

[0132] It should be noted that no increase in the Si atom ratio or O atom ratio was observed when only 3 minutes of O2 plasma treatment was performed, or when CF4 plasma treatment was performed instead of O2 plasma treatment.

[0133] -Industry Applicability-

[0134] This disclosure enables its use in industry as a conductive component.

[0135] - Symbol Explanation -

[0136] 1: Multilayer wiring substrate (conductive film)

[0137] 2: Installing components

[0138] 3: Substrate

[0139] 4: Thin film substrate

[0140] 5: First insulator

[0141] 5a: Adhesive part

[0142] 5b: Protrusion

[0143] 5c: Flat area

[0144] 6: Second Insulator

[0145] 7: First trench section

[0146] 7a: Bottom surface (first bottom surface)

[0147] 7b: Side view (first side view)

[0148] 7c: Corner

[0149] 8: Second groove section

[0150] 8a: Bottom surface (second bottom surface)

[0151] 8b: Side view (second side view)

[0152] 8c: Corner

[0153] 13: First metal wire

[0154] 131: Adhesive Layer

[0155] 132: Conductive layer (first conductive layer)

[0156] 17: Second metal wire

[0157] 171: Adhesive Layer

[0158] 172: Conductive layer (second conductive layer)

[0159] 20: Overlapping Patterns

[0160] 21: Connecting Area

[0161] 22: Conductor section

[0162] 30: Fictitious pattern

[0163] 31: Dummy conductive wire

[0164] P: Intersection

[0165] D1: Angle (First Angle)

[0166] D2: Angle (Second Angle)

[0167] L1: Thickness (first thickness)

[0168] L2: Thickness (Second Thickness)

[0169] W1: Slot width (first slot width)

[0170] W2: Slot width (second slot width).

Claims

1. A conductive film, characterized in that: The conductive film includes a first insulator, a first groove, a first metal wire, and a second insulator. The first insulator is sheet-shaped and has multiple protrusions on its upper surface. The first groove is formed on the upper surface of the first insulator. The first metal wire is arranged along the first groove. The second insulator is sheet-shaped and is stacked directly above the first insulator. The plurality of protrusions contain SiO2. The plurality of protrusions protrude upwards and enter the second insulator.

2. The conductive film according to claim 1, characterized in that: The first insulator contains Si atoms. The Si content of the first insulator is greater than the Si content of the second insulator.

3. The conductive film according to claim 2, characterized in that: The first insulator has a flat portion that contacts the second insulator. In the flat portion, the first insulator and the second insulator are bonded together via Si atoms.

4. The conductive film according to any one of claims 1 to 3, characterized in that: The first insulator comprises a resin material, which comprises a polymer having a silicon base.

5. The conductive film according to any one of claims 1 to 4, characterized in that: The conductive film also includes a second groove and a second metal wire. The second groove is formed on the upper surface of the second insulator, and the second metal wire is arranged along the second groove.

6. The conductive film according to claim 5, characterized in that: The conductive film is transparent. The first groove has a first bottom surface and a first side surface. The first bottom surface is located below the first metal wire, and the first side surface is located to the side of the first metal wire and connected to the first bottom surface. The second groove has a second bottom surface and a second side surface. The second bottom surface is located below the second metal wire, and the second side surface is located to the side of the second metal wire and connected to the second bottom surface. The angle between the second side surface and the second bottom surface is greater than the angle between the first bottom surface and the first side surface.

7. The conductive film according to claim 6, characterized in that: The first metal wire has a first bonding layer and a first conductive layer. The first adhesive layer covers the inner surface of the first groove, and the first conductive layer is disposed on the first adhesive layer. The second metal wire has a second bonding layer and a second conductive layer, the second bonding layer covering the inner surface of the second groove. The second conductive layer is disposed on the second bonding layer. The thickness of the second adhesive layer on the second bottom surface is greater than the thickness of the first adhesive layer on the first bottom surface.

8. The conductive film according to claim 6, characterized in that: The conductive film further includes a first blackening layer and a second blackening layer. The first blackening layer is stacked on the upper surface of the first metal wire. The second blackening layer is stacked on the upper surface of the second metal wire. The thickness of the first blackening layer is greater than the thickness of the second blackening layer.

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