conductive film

Abstract

To provide a conductive film having excellent specific resistance while capable of preventing outgas from an organic resin base material from contacting with a copper layer.SOLUTION: There is provided a conductive film 1 which has an organic resin base material 2, an inorganic layer 3 disposed on one side in the thickness direction of the organic resin base material 2 and a copper layer 4 directly disposed on one surface in the thickness direction of the inorganic layer, wherein the copper layer 4 has a boundary vicinity region 4A including a boundary with the inorganic layer 3 and a boundary separation region 4B disposed on one surface in the thickness direction of the boundary vicinity region 4A and in transmission electron microscopic observation of a cross-sectional section of the copper layer 4, there is a difference in contrast between the boundary vicinity region 4A and the boundary separation region 4B.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a conductive film.

Background Art

[0002] Conventionally, a conductive film including a base material and a metal layer in this order is known. Such a conductive film is used, for example, as a conductor layer for forming an electrode pattern in various devices such as flat panel displays and touch panels.

[0003] Also, such a conductive film is manufactured, for example, by disposing a metal layer on one surface in the thickness direction of a base material by a sputtering method.

[0004] On the other hand, in the production of the above-described conductive film, outgas from the base material may be generated. Such outgas forms metal oxide on the other surface in the thickness direction of the metal layer. Then, there is a problem that the adhesion between the base material and the metal layer decreases.

[0005] In contrast, a conductive film including a barrier layer (inorganic layer) between the base material and the metal layer has been studied. According to the barrier layer, it is possible to suppress the outgas from the base material from contacting the metal layer, and thus the above problem can be solved.

[0006] As such a conductive film, a conductive film including a resin film, an inorganic layer, and a copper layer in this order has been proposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] On the other hand, adding a barrier layer has the drawback of increasing the resistivity of the metal layer (copper layer).

[0009] The present invention aims to provide a conductive film with excellent resistivity while suppressing outgassing from the organic resin substrate into contact with the copper layer. [Means for solving the problem]

[0010] The present invention [1] comprises an organic resin substrate, an inorganic layer disposed on one side in the thickness direction of the organic resin substrate, and a copper layer disposed directly on one side in the thickness direction of the inorganic layer, wherein the copper layer has a boundary region including the boundary with the inorganic layer and a boundary separation region disposed on one side in the thickness direction of the boundary region, and includes a conductive film in which, in transmission electron microscope observation of the cross-section of the copper layer, there is a difference in contrast between the boundary region and the boundary separation region.

[0011] The present invention [2] includes the conductive film described in [1] above, wherein the thickness of the copper layer is 50 nm or more.

[0012] The present invention [3] includes the conductive film described in [1] or [2] above, wherein the thickness of the copper layer is 300 nm or less.

[0013] The present invention [4] includes a conductive film according to any one of the above [1] to [3], wherein the thickness of the inorganic layer is 2 nm or more and 15 nm or less. [Effects of the Invention]

[0014] The conductive film of the present invention comprises an inorganic layer. Therefore, during the manufacturing of the conductive film, it is possible to suppress outgassing from the organic resin substrate into contact with the copper layer. As a result, it is possible to suppress a decrease in adhesion between the organic resin substrate and the copper layer.

[0015] Moreover, the conductive film of the present invention has, in the copper layer, a boundary-near region including the boundary with the inorganic layer and a boundary-separated region disposed on one side in the thickness direction of the boundary-near region. In the cross-section of the copper layer, in a transmission electron microscope (TEM) observation, there is a contrast difference between the boundary-near region and the boundary-separated region. Therefore, the resistivity of the copper layer can be lowered.

Brief Description of the Drawings

[0016] [Figure 1] FIG. 1 shows an embodiment of the conductive film of the present invention. [Figure 2] FIGS. 2A to 2C show an embodiment of a method for manufacturing a conductive film. FIG. 2A shows a first step of preparing an organic resin substrate. FIG. 2B shows a second step of disposing an inorganic layer on one side in the thickness direction of the organic resin substrate. FIG. 2C shows a third step of disposing a copper layer on one side in the thickness direction of the inorganic layer. [Figure 3] FIG. 3 is a TEM image of the cross-section of the copper layer of Example 1. [Figure 4] FIG. 4 is a TEM image of the cross-section of the copper layer of Example 2. [Figure 5] FIG. 5 is a TEM image of the cross-section of the copper layer of Example 3. [Figure 6] FIG. 6 is a TEM image of the cross-section of the copper layer of Comparative Example 1.

Embodiments for Carrying Out the Invention

[0017] 1. Conductive Film Referring to FIG. 1, an embodiment of the conductive film of the present invention will be described.

[0018] In FIG. 1, the vertical direction on the paper surface is the vertical direction (thickness direction). Also, the upper side of the paper surface is the upper side (one side in the thickness direction). Also, the lower side of the paper surface is the lower side (the other side in the thickness direction). Also, the left-right direction and the depth direction on the paper surface are plane directions orthogonal to the vertical direction. Specifically, it conforms to the direction arrows in each figure.

[0019] The conductive film 1 has a film shape (including a sheet shape) with a predetermined thickness. The conductive film 1 extends in a plane direction orthogonal to the thickness direction. The conductive film 1 has a flat upper surface and a flat lower surface.

[0020] As shown in FIG. 1, the conductive film 1 includes an organic resin substrate 2, an inorganic layer 3 disposed on one side in the thickness direction of the organic resin substrate 2, and a copper layer 4 disposed directly on one side in the thickness direction of the inorganic layer 3. Specifically, the conductive film 1 includes an organic resin substrate 2, an inorganic layer 3 disposed directly on the upper surface (one side in the thickness direction) of the organic resin substrate 2, and a copper layer 4 disposed directly on the upper surface (one side in the thickness direction) of the inorganic layer 3.

[0021] The thickness of the conductive film 1 is, for example, 1 μm or more, preferably 5 μm or more, and, for example, 300 μm or less, preferably 200 μm or less.

[0022] <Organic resin substrate> The organic resin substrate 2 has a film shape. The organic resin substrate 2 has flexibility. The organic resin substrate 2 is disposed over the entire lower surface of the inorganic layer 3 so as to contact the lower surface of the inorganic layer 3. The organic resin substrate 2 is the lowermost layer of the conductive film 1.

[0023] Examples of the organic resin substrate 2 include polymer films.

[0024] Examples of the material of the polymer film include polyester resins, (meth)acrylic resins, olefin resins, polycarbonate resins, polyethersulfone resins, polyarylate resins, melamine resins, polyamide resins, polyimide resins, cellulose resins, and polystyrene resins, and preferably, polyester resins.

[0025] Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and preferably, polyethylene terephthalate.

[0026] Examples of (meth)acrylic resins include polymethyl methacrylate.

[0027] Examples of olefin resins include polyethylene, polypropylene, and cycloolefin polymers.

[0028] Examples of cellulose resins include triacetylcellulose.

[0029] The thickness of the organic resin substrate 2 is, for example, 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, even more preferably 50 μm or more, particularly preferably 100 μm or more, and also, for example, 300 μm or less, preferably 200 μm or less, and more preferably 150 μm or less.

[0030] The thickness of the organic resin substrate 2 can be measured using a dial gauge (PEACOCK, "DG-205").

[0031] Furthermore, the organic resin substrate 2 is preferably transparent. Specifically, the total light transmittance (JIS K 7375-2008) of the organic resin substrate 2 is, for example, 80% or more, preferably 85% or more.

[0032] <Inorganic layer> The inorganic layer 3 is a layer used in the manufacturing method of the conductive film 1, described later, to suppress outgassing from the organic resin substrate 2 from coming into contact with the copper layer 4.

[0033] The inorganic layer 3 has a film shape. The inorganic layer 3 is arranged over the entire upper surface of the organic resin substrate 2 so as to be in contact with the upper surface of the organic resin substrate 2. The inorganic layer 3 is also arranged over the entire lower surface of the copper layer 4 so as to be in contact with the lower surface of the copper layer 4.

[0034] Furthermore, the inorganic layer 3, as will be explained in more detail later, is a sputtered layer because it is formed by the sputtering method.

[0035] The material of the inorganic layer 3 is not particularly limited, as long as it is an inorganic substance other than copper as a pure metal. Specifically, preferred materials for the inorganic layer 3 include metals (excluding copper as a pure metal) and metal oxides (excluding copper oxide).

[0036] Examples of metals include Ni, In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Pd, W, their alloys, and alloys of these with copper.

[0037] Examples of metal oxides include oxides of the above-mentioned metals. Preferably, indium-containing oxides are used as metal oxides. Examples of indium-containing oxides include indium-tin composite oxide (ITO).

[0038] Furthermore, the metal oxide may be either crystalline or amorphous.

[0039] Preferably, metal oxides are used as the material for the inorganic layer 3.

[0040] The materials for the inorganic layer 3 can be used individually or in combination of two or more types.

[0041] The thickness of the inorganic layer 3 is, for example, 2 nm or more from the viewpoint of gas barrier properties, and, for example, 15 nm or less, preferably 10 nm or less, and more preferably 7 nm or less from the viewpoint of processability.

[0042] The thickness of the inorganic layer 3 can be measured, for example, by observing the cross-section of the conductive film 1 using a transmission electron microscope.

[0043] <Copper layer> The copper layer 4 is a conductive layer. The copper layer 4 is formed into a desired pattern as needed.

[0044] The copper layer 4 has a film shape. The copper layer 4 is arranged across the entire upper surface of the inorganic layer 3 so as to be in contact with the upper surface of the inorganic layer 3. The copper layer 4 is the uppermost layer of the conductive film 1.

[0045] The copper layer 4 has a boundary-near region 4A that includes the boundary with the inorganic layer 3, and a boundary-separated region 4B that is located on one side in the thickness direction of the boundary-near region 4A.

[0046] Furthermore, as will be explained in more detail later, the copper layer 4 is a sputtered layer because it is formed by the sputtering method.

[0047] Examples of materials for the copper layer 4 include copper (copper as pure metal) and copper alloys.

[0048] The metals that make up the copper alloy are not particularly limited, but examples include silver, tin, chromium, and zirconium.

[0049] From the viewpoint of conductivity, copper (copper as a pure metal) is preferred as the material for the copper layer 4. In other words, the copper layer 4 is preferably made of copper (copper as a pure metal).

[0050] The resistivity of copper layer 4 is, for example, 2.300 × 10⁻⁶ -8 Ω·m or less, preferably 2.280 × 10 -8 Ω·m or less, more preferably 2.200 × 10 -8 Ω·m or less, and usually 1.000 × 10⁻⁶ -8 It is greater than or equal to Ω·m.

[0051] The resistivity can be calculated by multiplying the surface resistance value, measured using the four-terminal method in accordance with JIS K7194, by the thickness of the copper layer 4.

[0052] The surface resistance of the copper layer 4 is, for example, 0.222 Ω / □ or less, preferably 0.220 Ω / □ or less, and more preferably 0.210 Ω / □ or less.

[0053] The lower limit of the surface resistance of the copper layer 4 is not particularly limited. For example, the surface resistance of the copper layer 4 is usually greater than 0 Ω / □.

[0054] The surface resistance can be measured using the four-terminal method in accordance with JIS K7194.

[0055] The thickness of the copper layer 4 is, for example, 50 nm or more, preferably 70 nm or more, more preferably 90 nm or more, and even more preferably 100 nm or more, from the viewpoint of resistance, and, for example, 300 nm or less, preferably 250 nm or less, more preferably 200 nm or less, even more preferably 150 nm or less, and particularly preferably 120 nm or less, from the viewpoint of productivity.

[0056] The thickness of the copper layer 4 is the sum of the boundary vicinity region 4A (described later) and the boundary separation region 4B (described later), and can be measured, for example, by observing the cross-section of the copper layer 4 using a transmission electron microscope.

[0057] [Boundary Neighbor Region] The boundary vicinity region 4A is the region of the copper layer 4 that includes the boundary with the inorganic layer 3 and is located near that boundary.

[0058] In transmission electron microscopy observation of the cross-section of copper layer 4, the region 4A near the boundary appears relatively white.

[0059] The average thickness of the boundary region 4A is, for example, 1 nm or more, preferably 5 nm or more, more preferably 10 nm or more, and also, for example, 50 nm or less, preferably 30 nm or less, more preferably 20 nm or less.

[0060] The average thickness of the boundary region 4A can be measured, for example, by observing the cross-section of the copper layer 4 using a transmission electron microscope. Specifically, the average thickness of the boundary region 4A is calculated by measuring the thickness of the boundary region 4A at 1 nm intervals within one field of view [nm] of the transmission electron microscope, and then dividing the sum of these thicknesses by one field of view [nm].

[0061] [Boundary separation area] The boundary separation region 4B is located on one side in the thickness direction of the boundary proximity region 4A within the copper layer 4, and is continuous with the boundary proximity region 4A, while being separated from the boundary with the inorganic layer 3. In other words, the boundary separation region 4B is located on the opposite side of the inorganic layer 3 from the boundary proximity region 4A.

[0062] In transmission electron microscopy observation of the cross-section of copper layer 4, the boundary separation region 4B appears relatively dark.

[0063] The average thickness of the boundary separation region 4B is, for example, 30 nm or more, preferably 50 nm or more, more preferably 70 nm or more, and also, for example, 250 nm or less, preferably 200 nm or less, more preferably 150 nm or less, and even more preferably 100 nm or less.

[0064] The average thickness of the boundary separation region 4B can be measured, for example, by observing the cross-section of the copper layer 4 using a transmission electron microscope. Specifically, the average thickness of the boundary separation region 4B is calculated by measuring the thickness of the boundary separation region 4B at 1 nm intervals within one field of view [nm] of the transmission electron microscope, and then dividing the sum of these thicknesses by one field of view [nm].

[0065] In transmission electron microscopy observation of the cross-section of copper layer 4, there is a difference in contrast between the region near the boundary 4A and the region separated from the boundary 4B. In other words, when there is a difference in contrast, the region near the boundary 4A and the region separated from the boundary 4B become visible.

[0066] Differences in contrast can be seen, for example, as a boundary being visible between the near-boundary region 4A and the separated-boundary region 4B, meaning that each region appears layered and stacked in the thickness direction; as if there are striped patterns intersecting the planar direction in the near-boundary region 4A and the separated-boundary region 4B, with the spacing of these stripes appearing different in each region; and as if the grain size observed in the near-boundary region 4A and the separated-boundary region 4B appears to differ in each region.

[0067] In transmission electron microscopy observation of the cross-section of the copper layer 4, if there is a difference in contrast between the region near the boundary 4A and the region separated from the boundary 4B, the copper layer 4 has excellent resistivity.

[0068] 2. Method for manufacturing conductive film The method for manufacturing the conductive film 1 will be explained with reference to Figures 2A to 2C.

[0069] The method for manufacturing the conductive film 1 comprises a first step of preparing an organic resin substrate 2, a second step of arranging an inorganic layer 3 on one side in the thickness direction of the organic resin substrate 2 by sputtering, and a third step of arranging a copper layer 4 on one side in the thickness direction of the inorganic layer 3 by sputtering. In this method, each layer is arranged sequentially, for example, using a roll-to-roll method. In such cases, the conveying speed is, for example, 1.0 m / min or more, and for example, 20.0 m / min or less.

[0070] Furthermore, in the method for manufacturing the conductive film 1, the sputtering method is performed in the second and third steps while supplying sputtering gas.

[0071] In the method for manufacturing the conductive film 1, in the second step, an inert gas (described later) is supplied as the sputtering gas. Preferably, in the second step, an inert gas (described later) is supplied as the sputtering gas, along with oxygen gas.

[0072] In the method for manufacturing the conductive film 1, in the third step, in order to form the desired copper layer 4, the target material and sputtering conditions are appropriately set and sputtering is performed multiple times. In the third step, the number of sputtering cycles is, for example, two or more, preferably four or more, and for example, 20 or fewer, preferably 10 or fewer.

[0073] In the method for manufacturing the conductive film 1, in the third step, an inert gas (described later) is supplied as the sputtering gas. Preferably, in the first sputtering of the third step, an inert gas (described later) and oxygen gas are supplied as the sputtering gas, and in the second and subsequent sputtering of the third step, only an inert gas (described later) is supplied as the sputtering gas.

[0074] In other words, in the method for manufacturing the conductive film 1, for example, in the second step, an inorganic layer 3 is placed on one side in the thickness direction of the organic resin substrate 2 by sputtering, with oxygen gas supplied along with an inert gas, and in the third step, a copper layer 4 is placed on one side in the thickness direction of the inorganic layer 3 by sputtering, with only inert gas supplied. Alternatively, for example, in the second step, an inorganic layer 3 is placed on one side in the thickness direction of the organic resin substrate 2 by sputtering, with only inert gas supplied during the first sputtering, and a copper layer 4 is placed on one side in the thickness direction of the inorganic layer 3 by sputtering, with oxygen gas supplied along with an inert gas during the first sputtering, and only inert gas supplied during the second and subsequent sputterings. Furthermore, for example, in the second step, an inorganic layer 3 is placed on one side in the thickness direction of the organic resin substrate 2 by sputtering, with oxygen gas supplied along with an inert gas, and in the third step, a copper layer 4 is placed on one side in the thickness direction of the inorganic layer 3 by sputtering, with oxygen gas supplied along with an inert gas in the first sputtering, and with only inert gas supplied in the second and subsequent sputtering. Preferably, in the method for manufacturing the conductive film 1, in the second step, an inorganic layer 3 is placed on one side in the thickness direction of the organic resin substrate 2 by sputtering, with oxygen gas supplied along with an inert gas, and in the third step, a copper layer 4 is placed on one side in the thickness direction of the inorganic layer 3 by sputtering, with oxygen gas supplied along with an inert gas in the first sputtering, and with only inert gas supplied in the second and subsequent sputtering.

[0075] The following description details the method for manufacturing the conductive film 1.

[0076] [1st step] In the first step, an organic resin substrate 2 is prepared as shown in Figure 2A.

[0077] [Second process] In the second step, as shown in Figure 2B, an inorganic layer 3 is placed on one side in the thickness direction of the organic resin substrate 2 by sputtering.

[0078] To place an inorganic layer 3 on one side in the thickness direction of an organic resin substrate 2 by sputtering, first, if necessary, a surface treatment is applied to one side in the thickness direction of the organic resin substrate 2.

[0079] Examples of surface treatments include corona treatment, plasma treatment, flame treatment, ozone treatment, primer treatment, glow treatment, and saponification treatment.

[0080] Next, in the sputtering method, the target (material for the inorganic layer 3) and the organic resin substrate 2 are placed facing each other in the vacuum chamber of the sputtering deposition apparatus. Then, by supplying sputtering gas and applying voltage from the power supply, gas ions are accelerated and irradiated onto the target, ejecting the target material from the target surface. This target material is then deposited on the surface (one side in the thickness direction) of the organic resin substrate 2 to form the inorganic layer 3.

[0081] Alternatively, the sputtering gas may consist of only an inert gas (e.g., argon gas), or an inert gas and oxygen gas. Preferably, the sputtering gas consists of an inert gas and oxygen gas.

[0082] When supplying oxygen gas together with an inert gas, the flow rate is, for example, 5 sccm or more, preferably 10 sccm or more, more preferably 20 sccm or more, even more preferably 30 sccm or more, and particularly preferably 40 sccm or more, and also, for example, 200 sccm or less, preferably 100 sccm or less.

[0083] Furthermore, when oxygen gas is supplied together with the inert gas, the flow rate ratio of the inert gas to the flow rate of the oxygen gas is, for example, 3.5 or more, preferably 10 or more, and for example, 200 or less, preferably 100 or less, and more preferably 50 or less.

[0084] The atmospheric pressure during sputtering is, for example, 0.1 Pa or higher, preferably 0.2 Pa or higher, and for example, 2.0 Pa or lower, preferably 1.0 Pa or lower.

[0085] The power supply may be, for example, a DC power supply, an AC power supply, an MF power supply, or an RF power supply. A combination of these may also be used.

[0086] The discharge output is, for example, 1.0 kW or more, preferably 5.0 kW or more, and also, for example, 20 kW or less.

[0087] This arranges the inorganic layer 3 on one side in the thickness direction of the organic resin substrate 2.

[0088] [3rd step] In the third step, as shown in Figure 2C, a copper layer 4 is placed on one side in the thickness direction of the inorganic layer 3 by sputtering.

[0089] In the sputtering method, a target (material for the copper layer 4) and an inorganic layer 3 are placed facing each other in a vacuum chamber of a sputtering deposition apparatus. Next, sputtering gas is supplied and a voltage is applied from a power supply to accelerate gas ions, which are then irradiated onto the target, ejecting the target material from the target surface. This target material is then deposited onto the surface (one side in the thickness direction) of the inorganic layer 3 to form the copper layer 4.

[0090] In the third step, in order to form the desired copper layer 4, sputtering is performed multiple times by appropriately setting the target material and sputtering conditions. In the third step, the number of sputtering cycles is, for example, two or more, preferably four or more, and for example, 20 or fewer, preferably 10 or fewer.

[0091] Furthermore, as the sputtering gas, for example, only an inert gas (e.g., argon gas) may be supplied, or an inert gas and oxygen gas may be supplied. More specifically, as the sputtering gas, for example, only an inert gas may be supplied for all sputtering, or an inert gas and oxygen gas may be supplied for the first sputtering, and only an inert gas may be supplied for the second and subsequent sputterings. Preferably, as the sputtering gas, an inert gas and oxygen gas may be supplied for the first sputtering, and only an inert gas may be supplied for the second and subsequent sputterings.

[0092] When supplying oxygen gas together with the inert gas, the flow rate is less than the flow rate of oxygen gas in the second step described above, for example, 1 sccm or more, preferably 3 sccm or more, more preferably 5 sccm or more, and for example, 30 sccm or less, preferably 20 sccm or less, more preferably 15 sccm or less.

[0093] Furthermore, when oxygen gas is supplied together with the inert gas, the flow rate ratio of the inert gas to the flow rate of the oxygen gas is, for example, 40 or more, and for example, 500 or less, preferably 200 or less, more preferably 100 or less, and even more preferably 50 or less.

[0094] The atmospheric pressure during sputtering is, for example, 0.1 Pa or higher, preferably 0.2 Pa or higher, and for example, 2.0 Pa or lower, preferably 1.0 Pa or lower.

[0095] The power supply may be, for example, a DC power supply, an AC power supply, an MF power supply, or an RF power supply. A combination of these may also be used.

[0096] The discharge output is, for example, 5.0 kW or more, preferably 10.0 kW or more, and also, for example, 20 kW or less.

[0097] The film formation temperature (the temperature of the organic resin substrate 2 on which the inorganic layer 3 is placed) is, for example, 30°C or higher, and for example, 60°C or lower.

[0098] As a result, a copper layer 4 is formed on one side of the inorganic layer 3 in the thickness direction.

[0099] The copper layer 4 formed in this manner has a near-boundary region 4A that includes the boundary with the inorganic layer 3, and a boundary-separated region 4B located on one side in the thickness direction of the near-boundary region 4A. When observing the cross-section of the copper layer 4 with a transmission electron microscope, there is a difference in contrast between the near-boundary region 4A and the boundary-separated region 4B. Specifically, the near-boundary region 4A is formed by the first sputtering, and the boundary-separated region 4B is formed by the sputtering from the second to the final sputtering.

[0100] Based on the above, conductive film 1 is manufactured.

[0101] <Effects and Effects> The conductive film 1 includes an inorganic layer 3. Therefore, during the manufacturing of the conductive film 1, it is possible to suppress outgassing from the organic resin substrate 2 from coming into contact with the copper layer 4.

[0102] In more detail, outgassing may occur from the organic resin substrate 2 during the manufacturing of the conductive film 2. This outgassing can cause copper oxide to form on other surfaces in the thickness direction of the copper layer 4. This can lead to a decrease in adhesion between the organic resin substrate 2 and the copper layer 4.

[0103] On the other hand, the conductive film 1 includes an inorganic layer 3. This prevents the outgassing from coming into contact with the copper layer 4. As a result, the formation of copper oxide on other surfaces in the thickness direction of the copper layer 4 is suppressed, and consequently, a decrease in the adhesion between the organic resin substrate 2 (inorganic layer 3) and the copper layer 4 is suppressed.

[0104] Furthermore, the copper layer 4 of the conductive film 1 has a boundary-near region 4A that includes the boundary with the inorganic layer 3, and a boundary-separated region 4B located on one side in the thickness direction of the boundary-near region 4A. When observing the cross-section of the copper layer 4 with a transmission electron microscope, there is a difference in contrast between the boundary-near region 4A and the boundary-separated region 4B. Therefore, the resistivity of the copper layer 4 can be lowered.

[0105] <Variation> In the modified examples, components and processes similar to those in the first embodiment are given the same reference numerals, and their detailed descriptions are omitted. Furthermore, the modified examples can achieve the same effects and advantages as the first embodiment, unless otherwise specified. Moreover, the first embodiment and its modified examples can be combined as appropriate.

[0106] Furthermore, in the above description, the conductive film 1 comprises an organic resin substrate 2, an inorganic layer 3, and a copper layer 4 in order in the thickness direction. However, a functional layer (for example, a hard coat layer) can also be placed between the organic resin substrate 2 and the inorganic layer 3. In such a case, the conductive film 1 comprises an organic resin substrate 2, a hard coat layer, an inorganic layer 3, and a copper layer 4 in order in the thickness direction. [Examples]

[0107] The present invention will be further described below with reference to examples and comparative examples. However, the present invention is not limited in any way to the examples and comparative examples. Furthermore, specific numerical values ​​such as blending ratios (content ratios), physical properties, and parameters used in the following description can be replaced with the corresponding upper limits (numerical values ​​defined as "less than or equal to" or "less than") or lower limits (numerical values ​​defined as "greater than or equal to" or "greater than or equal to") of the blending ratios (content ratios), physical properties, and parameters described in the "Modes for Carrying Out the Invention" above.

[0108] <Manufacturing of conductive films> Example 1 The conductive film was manufactured using the following procedure.

[0109] [1st step] As the organic resin substrate, polyethylene terephthalate (125U48, manufactured by Toray Industries, Inc., 125 μm thick) was prepared.

[0110] [Second process] Based on the following conditions, an inorganic layer (ITO layer) (thickness 5 nm) was placed on one side in the thickness direction of an organic resin substrate by sputtering. {conditions} Equipment: Roll-to-roll sputtering system (winding type DC magnetron sputtering system) Inorganic layer material: ITO Gas: Argon gas and oxygen gas (oxygen gas flow rate 20 sccm) Flow rate ratio of inert gas flow rate to oxygen gas flow rate: 35 Discharge output: 7.2kW Atmospheric pressure in the deposition chamber: 0.4 Pa Driving speed: 8.0 m / min

[0111] [3rd step] Based on the following conditions, a copper layer (104 nm) was placed on one side of the inorganic layer in the thickness direction by sputtering. The sputtering process was performed eight times until the desired thickness was achieved. {conditions} Equipment: Roll-to-roll sputtering system (winding type DC magnetron sputtering system) Gas: Argon gas Discharge output: 14.7kW Atmospheric pressure in the deposition chamber: 0.4 Pa Film forming temperature: 40℃ Driving speed: 8.0 m / min

[0112] Furthermore, immediately after the sputtering in the second step, the first sputtering in the third step was performed.

[0113] Example 2 A conductive film was manufactured following the same procedure as in Example 1. However, the flow rate of oxygen gas in the second step was changed as described in Table 1.

[0114] Example 3 The conductive film was manufactured using the same procedure as in Example 2 for the first and second steps, and the conductive film was manufactured using the following procedure for the third step.

[0115] [3rd step] Based on the following conditions, a copper layer (12 nm thick) was placed on one side of the inorganic layer in the thickness direction by sputtering. Sputtering was performed only once. {conditions} Equipment: Roll-to-roll sputtering system (winding type DC magnetron sputtering system) Gas: Argon gas and oxygen gas (oxygen gas flow rate 15 sccm) Flow rate ratio of inert gas flow rate to oxygen gas flow rate: 47 Discharge output: 14.7kW Atmospheric pressure in the deposition chamber: 0.4 Pa Film forming temperature: 40℃ Driving speed: 8.0 m / min

[0116] Furthermore, immediately after the sputtering in the second step, the first sputtering in the third step was performed.

[0117] Next, a copper layer (92 nm thick) was added by sputtering, based on the following conditions. The sputtering process was repeated seven times until the desired thickness was achieved. {conditions} Equipment: Roll-to-roll sputtering system (winding type DC magnetron sputtering system) Gas: Argon gas Discharge output: 14.7kW Atmospheric pressure in the deposition chamber: 0.4 Pa Film forming temperature: 40℃ Driving speed: 8.0 m / min

[0118] Comparative Example 1 A conductive film was manufactured following the same procedure as in Example 1. However, the oxygen gas flow rate was changed as described in Table 1. Specifically, oxygen gas was not supplied in the second step.

[0119] <Rating> (Surface resistance) The surface resistance of the copper layer in each example and Comparative Example 1 was measured using the four-terminal method in accordance with JIS K7194. The results are shown in Table 1.

[0120] (specific resistance) The resistivity of the copper layer in each example and Comparative Example 1 was calculated by multiplying the surface resistance by the thickness of the copper layer. The results are shown in Table 1.

[0121] (Presence or absence of contrast difference) TEM images of the cross-section of the copper layer in each example and Comparative Example 1 are shown in Figures 3 to 6, and Table 1 shows the presence or absence of contrast differences between the region near the boundary and the region separated from the boundary in the copper layer of each example and Comparative Example 1.

[0122] <Consideration> Examples 1 to 3 and Comparative Example 1 demonstrate that, because they include an inorganic layer, outgassing from the organic resin substrate can be suppressed from coming into contact with the copper layer.

[0123] Furthermore, in Figure 3, in Example 1, a boundary line is partially visible between the region near the boundary and the region separated from the boundary in the copper layer. In other words, each region appears to be layered and stacked in the thickness direction. Therefore, the copper layer has a region near the boundary and a region separated from the boundary, and there is a difference in contrast between the region near the boundary and the region separated from the boundary.

[0124] Next, in Figure 4, in Example 2, a boundary line is visible between the region near the boundary and the region separated from the boundary in the copper layer. That is, each region appears to be layered and stacked in the thickness direction. Therefore, the copper layer has a region near the boundary and a region separated from the boundary, and there is a difference in contrast between the region near the boundary and the region separated from the boundary.

[0125] Furthermore, in Figure 5, the copper layer of Example 3 appears to have striped patterns in both the near-boundary region and the separated-boundary region, with the spacing of these stripes differing in each region. In addition, the grain size observed in the near-boundary region and the separated-boundary region appears to differ in each region. Therefore, the copper layer has both a near-boundary region and a separated-boundary region, and there is a difference in contrast between the near-boundary region and the separated-boundary region.

[0126] On the other hand, in Figure 6, in the copper layer of Comparative Example 1, no boundary is visible between the region near the boundary and the region between the boundary and the boundary. There are no striped patterns in the direction intersecting the plane between the region near the boundary and the region between the boundary and the boundary. The size of the crystal grains observed in the region near the boundary and the region between the boundary and the boundary are not different in each region. Therefore, there is no difference in contrast between the region near the boundary and the region between the boundary and the boundary of the copper layer.

[0127] Table 1 shows that even when an inorganic layer is present, there are regions near the boundary and regions separated from the boundary, and there is a difference in contrast between the regions near the boundary and separated from the boundary. Examples 1 to 3 can achieve lower resistivity than Comparative Example 1, in which there is no difference in contrast between the regions near the boundary and separated from the boundary.

[0128] Examples 1 to 3 have a resistivity of 2.300 × 10⁻⁶. -8 It can be reduced to Ω·m or less. Specifically, it can be shown that practicality can be ensured, particularly for applications as a conductive layer for patterning electrodes in various devices such as flat panel displays and touch panels, where a practical level of resistivity can be achieved.

[0129] [Table 1] [Explanation of symbols]

[0130] 1. Conductive film 2 Organic resin base material 3 Inorganic layer 4. Copper layer 4A realm near realm 4B Boundary Disruption Domain

Claims

1. Organic resin substrate and An inorganic layer disposed on one side in the thickness direction of the organic resin substrate, The inorganic layer comprises a copper layer directly disposed on one side in the thickness direction of the inorganic layer, The copper layer has a boundary region including the boundary with the inorganic layer, and a boundary separation region located on one side in the thickness direction of the boundary region. The thickness of the copper layer is 70 nm or more. The average thickness of the region near the boundary is 30 nm or less. A conductive film in which, when observed with a transmission electron microscope in a cross-section of the copper layer, there is a difference in contrast between the region near the boundary and the region separated from the boundary.

2. The conductive film according to claim 1, wherein the thickness of the copper layer is 300 nm or less.

3. The conductive film according to claim 1 or 2, wherein the thickness of the inorganic layer is 2 nm or more and 15 nm or less.

Images