Substrate with conductive film and method for manufacturing same

Abstract

The present invention relates to a substrate with a conductive film, the substrate having a substrate and a conductive film formed on at least one main surface of the substrate, the conductive film including a conductive layer, the conductive film being isolated by a slit portion, and the conductive film being formed on the conductive layer at an end portion of the conductive film isolated by the slit portion. The conductive layer is continuously covered with an oxide film.

Description

Technical Field

[0001] The present invention relates to a substrate with a conductive film and a method for manufacturing the same. Background Art

[0002] In recent years, the fifth-generation wireless system (5G) has been gradually popularized, and many electronic devices are mounted in automobiles and the like. However, when using these electronic devices, malfunction of the electronic devices is likely to occur due to radio wave interference or the like. As one of the methods for preventing radio wave interference, the use of an electromagnetic wave control member is considered.

[0003] Examples of the electromagnetic wave control member include radio wave absorbers such as λ / 4 type radio wave absorbers, frequency selective surfaces in which a patterned conductive film is provided on a substrate, etc. (Patent Document 1).

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-534975 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] In a substrate with a conductive film in which a pattern is formed on the conductive film by laser irradiation, etching, etc., ion migration occurs between the conductive films isolated by the pattern. When the ion migration proceeds, metal dissolves from the conductive film and precipitates in a dendritic shape to form dendritic crystals (dendrites), so that a short circuit occurs between the conductive films. Therefore, in order to block the electrical connection between the conductive films, it is usually necessary to perform passivation by providing an insulating film containing resin or the like on the conductive film. However, from the viewpoints of suppressing manufacturing costs and improving productivity, it is desirable not to provide an insulating film.

[0009] Therefore, an object of the present invention is to provide a substrate with a conductive film that exhibits excellent insulation reliability between conductive films even without providing an insulating film.

[0010] Means for Solving the Problems

[0011] The present inventors repeatedly conducted in-depth research and found that by forming an oxide film that continuously covers the conductive film at the end of the conductive film isolated by the slit portion, the above problems can be solved, and thus the present invention was completed.

[0012] That is, the present invention has the following configuration.

[0013] [1] A substrate with a conductive film, the substrate with a conductive film having a substrate and a conductive film formed on at least one main surface of the substrate. Among them, the conductive film includes a conductive layer, the conductive film is isolated by slit portions, and at the end of the conductive film isolated by the slit portions, the conductive layer is continuously covered by an oxide film.

[0014] [2] The substrate with a conductive film according to [1], wherein the conductive film includes a protective layer.

[0015] [3] The substrate with a conductive film according to [1], wherein the average height of the oxide film is more than twice the film thickness of the conductive film.

[0016] [4] The substrate with a conductive film according to [1], wherein the conductive layer includes silver.

[0017] [5] The substrate with a conductive film according to [1], wherein the substrate is glass.

[0018] [6] The substrate with a conductive film according to [1], wherein the substrate is resin.

[0019] [7] A manufacturing method of a substrate with a conductive film, wherein a part of the conductive film is removed by irradiating a conductive film including a conductive layer formed on the surface of the substrate with a laser, so that the conductive film is isolated by slit portions and an oxide film continuously covering the conductive layer is formed at the end of the conductive film isolated by the slit portions.

[0020] [8] The manufacturing method according to [7], wherein the pulse width of the laser is in picosecond or nanosecond level.

[0021] [9] The manufacturing method according to [7] or [8], wherein the wavelength of the laser is 500nm - 1500nm.

[0022]

[10] An electromagnetic wave control member, wherein the electromagnetic wave control member has the substrate with a conductive film according to any one of [1] - [6].

[0023]

[11] A radio wave absorber member, wherein the radio wave absorber member has the substrate with a conductive film according to any one of [1] - [6].

[0024]

[12] A frequency selective surface, wherein the frequency selective surface has the substrate with a conductive film according to any one of [1] - [6].

[0025] Advantages of the Invention

[0026] According to the present invention, it is possible to provide a substrate with a conductive film that exhibits excellent insulation reliability between the conductive films even without providing an insulating film. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a view showing one embodiment of the substrate with a conductive film of the present invention. Figure 1 (A) is a top view of the substrate with a conductive film, Figure 1 (B) is Figure 1 an enlarged view of a cross-section along the X-X line of the portion surrounded by a dashed line in the top view shown in (A).

[0028] Figure 2 It is a partial cross-sectional view of the substrate with a conductive film of one embodiment.

[0029] Figure 3 It is a scanning electron microscope image showing the shape of the oxide film of the substrate with a conductive film obtained in Example 1.

[0030] Figure 4 It is a graph showing the height of the oxide film of the substrate with a conductive film obtained in Example 1.

[0031] Figure 5 It is a graph showing the height of the oxide film of the substrate with a conductive film obtained in Example 2.

[0032] Figure 6 It is an optical microscope image after a voltage application test of the substrate with a conductive film obtained in Example 1.

[0033] Figure 7 It is an optical microscope image after a voltage application test of the substrate with a conductive film obtained in Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, the present invention will be described in detail, but the present invention is not limited to the following embodiments, and can be arbitrarily modified and implemented without departing from the gist of the present invention.

[0035] In addition, "~" indicating a numerical range is used in the sense of including the values described before and after it as the lower limit value and the upper limit value.

[0036] In the following drawings, sometimes the same reference numerals are given to components and parts that perform the same function for description, and sometimes repeated descriptions are omitted or simplified. In addition, the embodiments shown in the drawings are schematic for clearly explaining the present invention, and do not necessarily accurately represent the dimensions and scales of actual products.

[0037] "Substrate with a Conductive Film"

[0038] Figure 1The figure shows an embodiment of the substrate with a conductive film according to the present invention. Figure 1 (A) is a top view of the substrate with a conductive film, Figure 1 (B) is an enlarged cross-sectional view taken along the X-X line of the portion surrounded by the dashed line in the top view shown in (A).

[0039] As Figure 1 shown, the substrate 10 with a conductive film of the present embodiment is a substrate 10 with a conductive film having a substrate 11 and a conductive film 12 formed on at least one main surface of the substrate 11. It is characterized in that the conductive film 12 includes a conductive layer 15, the conductive film 12 is isolated by a slit portion 13, and at the end of the conductive film 12 isolated by the slit portion 13, the conductive layer 15 is continuously covered by an oxide film 14.

[0040] More specifically, as Figure 1 (A) shows, at the end of the conductive film 12 isolated by the slit portion 13 (the portion of the conductive film 12 isolated by the slit portion 13), an oxide film 14 is continuously formed so as to cover the conductive layer 15. It should be noted that Figure 1 there are three slit portions formed in parallel arrangement, but this is just one way, and the formation conditions of the slit portion such as the number and pattern of the slit portions can be appropriately changed.

[0041] In addition, as Figure 1 (B) shows, in this embodiment, the conductive film 12 has a structure in which the conductive layer 15 is sandwiched between a protective layer 21 and a protective layer 22. However, as will be described in detail later, this structure is just one way, and the conductive film 12 only needs to include the conductive layer 15.

[0042] <Substrate>

[0043] The material of the substrate is not particularly limited. For example, it can be a transparent substrate made of a transparent material. As the transparent substrate, for example, a glass substrate or a resin substrate (resin substrate) can be cited. It should be noted that in this specification, "transparent" means, for example, a visible light transmittance of 70% or more.

[0044] As the glass substrate, for example, a soda-lime glass, an alkali-free glass, a quartz glass, etc. can be used. Physical strengthening treatment or chemical strengthening treatment can be performed on the glass substrate. In addition, the glass substrate can be composed of a single piece of glass or can be formed by laminating multiple pieces of glass sandwiching a resin film (resin film), etc.

[0045] As the resin substrate, for example, substrates including acrylic resins such as polymethyl methacrylate, aromatic polycarbonate resins such as polycarbonate phenylene ester, and aromatic polyester resins such as polyethylene terephthalate (PET) can be cited.

[0046] The substrate does not necessarily need to be composed of a single member. For example, it can also be a composite substrate formed by laminating a resin substrate and a glass substrate, etc.

[0047] In order to easily form a uniform conductive film, and in order to fix the focus and perform laser processing, the shape of the substrate is preferably a flat plate shape. In addition, the thickness and size of the substrate are not particularly limited and can be appropriately adjusted according to the desired strength, light weight, etc. For example, the thickness of the substrate can be 0.05 mm or more, can be 0.1 mm or more, can be 1.0 mm or more, and can also be 3.0 mm or more. In addition, the thickness of the substrate can be 20.0 mm or less, can be 12.0 mm or less, can be 10.0 mm or less, can be 5.0 mm or less, and can be 4.0 mm or less.

[0048] When using a glass substrate as the substrate in this embodiment, the specific gravity of the glass substrate is preferably 2.4 or more and 3.0 or less. In addition, the Young's modulus of the glass substrate is preferably 60 GPa or more and 100 GPa or less. In addition, the average thermal expansion coefficient of the glass substrate from 50 °C to 350 °C is preferably 50×10 -7 / °C or more and 120×10 -7 / °C or less. If the glass substrate satisfies these physical property requirements, it can be sufficiently and appropriately used as a window material.

[0049] <Conductive film>

[0050] The conductive film is a film having conductivity. In this specification, "having conductivity" means that the resistivity at 20 °C is 100 Ω / □ or less, for example.

[0051] From the viewpoints of durability and the performance of the conductive film, the thickness of the conductive film is preferably 5 nm or more, more preferably 10 nm or more, further preferably 15 nm or more, still further preferably 50 nm or more, particularly preferably 80 nm or more, and extremely preferably 100 nm or more. In addition, from the viewpoints of stably forming the slit portion and productivity, the thickness is preferably 1500 nm or less, more preferably 1200 nm or less, further preferably 1000 nm or less, still further preferably 500 nm or less, particularly preferably 450 nm or less, and extremely preferably 400 nm or less.

[0052] Hereinafter, the configuration of the conductive film of this embodiment will be described in detail. The conductive film of this embodiment at least includes a conductive layer.

[0053] (Conductive layer)

[0054] The composition of the conductive layer is not particularly limited. For example, it preferably contains silver, aluminum, tin oxide doped with at least one of fluorine and antimony (SnO 2: metals such as F, Sb), indium tin oxide (ITO), titanium nitride, niobium nitride, chromium nitride, zirconium nitride, and hafnium nitride. Among them, in order to make the substrate with the conductive film exhibit excellent conductivity and low emissivity, the conductive layer preferably contains silver, more preferably has silver as the main component, and further preferably contains 95 atomic% or more of silver. It should be noted that in this specification, the main component means that the content rate relative to all constituent components is 50 atomic% or more.

[0055] In addition, the above-mentioned conductive layer mainly composed of silver may contain one or more additive elements such as gold, palladium, copper, bismuth, neodymium, platinum, etc. By making the conductive layer mainly composed of silver contain such additive elements, the diffusion of silver can be suppressed and the moisture resistance can be improved. It should be noted that the additive elements are not limited to the elements exemplified above, and any element can be added as long as the effects of the present invention are exerted.

[0056] The sheet resistance value of the conductive layer can be 0.01 Ω / square or more, can be 0.1 Ω / square or more, and can also be 1 Ω / square or more. In addition, from the viewpoint of ensuring the performance as an electromagnetic wave control member, the resistance value of the conductive layer is preferably 100 Ω / square or less, more preferably 50 Ω / square or less, and further preferably 20 Ω / square or less. The sheet resistance value can be measured by a four-terminal measuring device, or can also be measured by a Hall effect measuring device or an eddy current method non-contact resistance measuring device.

[0057] The normal emissivity εn of the conductive layer is preferably 0.1 or less. When the normal emissivity εn of the conductive layer is 0.1 or less, it has excellent heat barrier properties and heat shielding properties, so the breakage of the substrate can be effectively prevented even in case of fire. The normal emissivity εn can be measured by the method specified in JIS R3106 (2019).

[0058] Although the thickness of the conductive layer also depends on the setting of the protective layer described later, from the viewpoint of ensuring the performance as an electromagnetic wave control member, it is preferably 0.1 nm or more, more preferably 1 nm or more, and further preferably 5 nm or more. In addition, from the viewpoints of productivity and maintaining visible light transmittance, the thickness is preferably 100 nm or less, more preferably 50 nm or less, and further preferably 20 nm or less.

[0059] (Protective layer)

[0060] In this embodiment, the conductive film preferably further includes a protective layer in addition to the conductive layer. That is, the conductive film is preferably a laminate in which multiple layers are laminated.

[0061] When the conductive film is a laminate, as its structure, it is preferable to laminate a conductive layer / protective layer, or a protective layer / conductive layer / protective layer, or laminate them alternately multiple times from the substrate side. By disposing the protective layer adjacent to the conductive layer, oxidation of the metal in the conductive layer in a high-temperature environment can be suppressed. In addition, by disposing the protective layer on the outermost layer, contact between the conductive layer and oxygen and moisture in the air can be prevented, deterioration of the conductive film can be suppressed. In addition, since the conductive layer is not exposed on the surface, insulation reliability can be further improved. In addition, by disposing a protective layer between the substrate and the conductive layer, the bonding strength between the conductive layer and the substrate can be improved.

[0062] It should be noted that when the protective layer is formed on the outermost layer, the protective layer can be provided on the entire surface of the outermost surface, or can be provided only on a part of the outermost surface.

[0063] The number of layers constituting the conductive film is not particularly limited. For example, it can be 1 layer, 2 layers, or 3 layers. In addition, when the conductive film is a laminate formed by laminating a plurality of layers, other films described later can also be sandwiched between the layers.

[0064] Examples of the material of the protective layer include: metal oxides, metals. Specific examples of the metal oxide include: zinc oxide, aluminum oxide, tin oxide, titanium oxide. In addition, examples of the metal include: titanium, Zn alloys. In addition, the material constituting the protective layer can be only one kind, or can contain two or more kinds. When the conductive film includes a plurality of protective layers, the materials of each layer can be different.

[0065] When the conductive film includes a protective layer, the thickness of the protective layer is not particularly limited. For example, it can be 0.5 nm to 100 nm, or can be 1 nm to 50 nm.

[0066] The method for forming the conductive layer and the protective layer is not particularly limited. For example, physical vapor deposition methods (vacuum evaporation method, ion plating method, magnetron sputtering method, etc.), chemical vapor deposition methods (thermal CVD method, plasma CVD method, photo CVD method, etc.), ion beam sputtering method, etc. can be used. In the case of a large film formation area, from the viewpoint of easy control of thickness uniformity and excellent productivity, a DC magnetron sputtering method, a DC pulsed magnetron sputtering method, or an AC dual magnetron sputtering method is preferable.

[0067] The conductive layer and the protective layer can be directly formed on the substrate, or can be indirectly formed on the substrate. The method of indirect formation is not particularly limited, and examples include a method of attaching a conductive layer or a protective layer formed on a resin film to the substrate and then peeling off the resin film.

[0068] Within the range where the effects of the present invention are exhibited, the substrate with a conductive film in the present embodiment can have a film (other film) different from the conductive film.

[0069] <Slit portion>

[0070] In the substrate with a conductive film according to this embodiment, typically a part of the conductive film is removed by laser irradiation or the like, and thus is isolated by a prescribed slit portion. In this embodiment, as the slit portion, for example, a form in which the conductive film is entirely removed and the substrate becomes the outermost surface can be cited. However, in this embodiment, for example, a form including at least one layer of a film other than the conductive film (other film) can also be used. In addition, as long as the conductive films partitioning the slit portion are not electrically connected, a part of the conductive film may remain.

[0071] Generally, in the substrate with a conductive film from which a part of the conductive film has been removed, the conductive layer contained in the conductive film is exposed at the end of the slit portion. Therefore, when a voltage is applied to the substrate with a conductive film, metal contained in the conductive layer undergoes ionic migration, thereby forming dendrites. When the dendrites grow, a short circuit is caused. Therefore, usually after the slit portion is formed, an insulating film containing resin or the like is provided on the surface of the conductive film, thereby performing passivation.

[0072] The present inventors found that, as Figure 1 shown, by forming an oxide film 14 in such a manner as to continuously cover the end portion of the conductive film 12 (the end portion of the slit portion) isolated by the slit portion 13, ionic migration is suppressed. As a result, even without providing an insulating film that has been essential in the past, a substrate 10 with a conductive film having excellent insulation reliability was obtained. It should be noted that in this specification, "the oxide film continuously covers the conductive layer" means that an oxide film is formed at the end portion of the slit portion, that is, the end face of the conductive film, and the conductive layer is not exposed. For example, as Figure 1 (B) shows, it may be a form in which an oxide film is formed from the surface of the substrate along the end face of the conductive film to the surface of the conductive film at the end portion of the slit portion.

[0073] The formation of the oxide film can be performed, for example, by forming the slit portion while applying heat using a laser. Specifically, for example, a method of forming the slit portion using a laser with a pulse width in the picosecond or nanosecond range can be cited.

[0074] In this embodiment, the average height of the oxide film is preferably 2 times or more the film thickness of the conductive film. By the average height of the oxide film being 2 times or more the film thickness of the conductive film, the electrical connection between the conductive films can be suppressed for a long time, and excellent insulation can be maintained. The average height of the oxide film is more preferably 2.5 times or more the film thickness of the conductive film, further preferably 3 times or more the film thickness of the conductive film, and particularly preferably 5 times or more the film thickness of the conductive film. In addition, from the viewpoint of ensuring the performance as an electromagnetic wave control member, the upper limit of the average height of the oxide film is preferably 15 times or less the film thickness of the conductive film, and more preferably 10 times or less the film thickness of the conductive film.

[0075] Here, the height of the oxide film refers to the distance in the vertical direction from the bottom surface to the surface of the oxide film when the main surface on the surface side (the side opposite to the substrate side) of the conductive film is used as the bottom surface.

[0076] Hereinafter, with reference to Figure 2 a more specific description of the height of the oxide film will be given. Figure 2 FIG. 1 is a partial cross-sectional view of a substrate 10 with a conductive film. A conductive film 12 having a structure in which a protective layer 22, a conductive layer 15, and a protective layer 21 are laminated in this order is formed on one surface of the substrate 11. The end of the conductive film 12 is covered with an oxide film 14 continuously formed from the main surface 12a on the side opposite to the substrate 11 of the conductive film 12 to the substrate 11. In addition, in a cross-sectional view in the thickness direction of the substrate 10 with a conductive film ( Figure 2 the cross-sectional view shown), the highest point in the oxide film 14 is set as point 14P. The height of the oxide film 14 in this case refers to the length L of the perpendicular line when a perpendicular line is drawn from point 14P to the main surface 12a on the side opposite to the substrate 11 of the conductive film 12. It should be noted that when there is no main surface 12a of the conductive film 12 directly below point P, the main surface 12a is defined as the surface extended in its surface extension direction, and the length L of the perpendicular line when a perpendicular line is drawn from point 14P to this surface is taken as the height of the oxide film 14.

[0077] In addition, the average height of the oxide film is the height of the oxide film when measured at three or more arbitrary locations, and can be measured by, for example, stylus surface profiling.

[0078] In addition, from the viewpoint of being able to suppress the electrical connection between conductive films for a long time and being able to maintain excellent insulation properties, the average height of the oxide film is preferably 400 nm or more, more preferably 500 nm or more, and further preferably 600 nm or more. In addition, from the viewpoint of ensuring aesthetic appearance, the upper limit of the average height of the oxide film is preferably 1500 nm or less, more preferably 1400 nm or less.

[0079] <Method for manufacturing a substrate with a conductive film>

[0080] The method for manufacturing a substrate with a conductive film according to this embodiment is characterized in that a part of the conductive film is removed by irradiating a conductive film containing a conductive layer formed on the surface of the substrate with a laser, so that the conductive film is isolated by a slit portion, and a continuous oxide film covering the conductive layer is formed at the end of the conductive film isolated by the slit portion.

[0081] Here, a substrate having a conductive film formed on its surface can be prepared, for example, by forming a conductive film on one main surface of the substrate using a sputtering method, a CVD method, or the like. In addition, as described above, the conductive film preferably contains silver.

[0082] Next, a laser is irradiated onto the conductive film formed on the surface of the substrate to remove the conductive film, thereby forming a slit portion. Additionally, an oxide film that continuously covers the conductive layer is formed at the end portions of the conductive film isolated by the slit portion.

[0083] There is no particular limitation on the type of laser. In order to output a high output power suitable for processing, it is preferable to use a solid-state laser or a gas laser. For example, as a solid-state laser, a YAG laser can be cited, and as a gas laser, an Ar ion laser can be cited.

[0084] The oxide film is formed by oxidizing the material of the conductive layer by the heat of the laser applied to the conductive film and becomes the terminal portion of the conductive layer. It should be noted that in the case where the conductive film has a protective layer, the oxide film is formed by the material of the conductive layer and the material of the oxidized protective layer being combined to lose the laminated structure. Therefore, it is preferable to perform laser irradiation using a laser with a pulse width in the picosecond or nanosecond range. Generally speaking, the smaller the pulse width, the smaller the influence of the heat of the laser on the object, and the larger the pulse width, the greater the influence of the heat. When using a laser with a large pulse width (for example, above picosecond level), an oxide film is likely to be formed at the end portions of the slit portion while removing the conductive film, and ion migration can be suppressed in the finally obtained substrate with the conductive film.

[0085] Specifically, the pulse width of the laser is preferably 1 ps or more, more preferably 10 ps or more, further preferably 100 ps or more, still further preferably 1 ns or more, particularly preferably 10 ns or more, and most preferably 20 ns or more. Additionally, in order to suppress the influence of the heat of the laser on the substrate, it is preferably 1 μs or less, more preferably 500 ns or less, and further preferably 100 ns or less.

[0086] In addition, the wavelength of the laser is preferably 500 nm to 1500 nm. By the wavelength of the laser being 500 nm or more, an oxide film can be formed by applying the heat of the laser to the conductive film. The wavelength of the laser is more preferably 600 nm or more, and further preferably 700 nm or more. By the wavelength of the laser being 1500 nm or less, the influence of the laser on the substrate can be suppressed. The wavelength of the laser is more preferably 1400 nm or less, and further preferably 1300 nm or less.

[0087] The scanning speed of the laser can be, for example, 10 mm / second to 1000 mm / second, or can also be 100 mm / second to 500 mm / second.

[0088] The magnitude of the energy of the laser can be adjusted by the output power of the laser. Specifically, the output power of the laser is preferably 0.1 W or more, and more preferably 1 W or more. Additionally, the output power of the laser is preferably 100 W or less, more preferably less than 100 W, and further preferably 50 W or less.

[0089] The shape of the slit portion formed in the conductive film can be appropriately set. For example, a specified shape such as linear, serrated, lattice, honeycomb, circular, etc. can be selected.

[0090] Among other laser irradiation conditions, the processing conditions of the laser (such as focusing conditions, frequency, etc.) can be appropriately set in consideration of the balance of the thickness of the substrate, the width of the slit portion, humidity, etc.

[0091] <Use>

[0092] The substrate with a conductive film of the present embodiment has selective radio wave transmissivity and phase adjustment effect, and thus can be applied to an electromagnetic wave control member. As the electromagnetic wave control member, radio wave absorber members such as λ / 4 type radio wave absorbers, frequency selective surfaces (FSS) can be cited. In addition, by introducing a frequency selective surface (FSS) into the conductive layer of the λ / 4 type radio wave absorber, a radio wave absorber thinner than the λ / 4 type can be realized. By setting the slit portion of the substrate with a conductive film of the present embodiment to an arbitrary shape, radio waves can be controlled for radio waves of a desired specific frequency.

[0093] Such an electromagnetic wave control member can be used in places where it is necessary to protect the human body, communication equipment, sensors, etc. from the influence of electromagnetic waves, and places where it is required to cope with communication obstacles and maloperations. For example, when a box-shaped radio wave absorber is used as a self-checkout register or a warehouse and automatic identification of goods is performed inside the radio wave absorber, unnecessary radio waves are suppressed by the radio wave absorber, and counting errors of goods can be prevented. In addition, visual recognition is sometimes required for the electromagnetic wave control member. Therefore, the visible light transmittance of the substrate with a conductive film is preferably 50% or more, more preferably 53% or more, and further preferably 55% or more. In addition, the visible light transmittance is preferably 90% or less, more preferably 80% or less. If the visible light transmittance is 50% or more, the existing objects can be seen through the substrate with a conductive film. The visible light transmittance is measured according to Japanese Industrial Standard JISR3106:1998 and calculated by the calculation formula in the case of using a standard D65 light source.

[0094] Examples

[0095] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. It should be noted that Example 1 is an example and Example 2 is a comparative example.

[0096] [Manufacture of Substrate with Conductive Film]

[0097] (Example 1)

[0098] A glass substrate with a thickness of 3 mm (manufactured by AGC, FL3) was prepared as the substrate, and a conductive film with a total thickness of 191 nm, which included a conductive layer mainly composed of silver (Ag) and a protective layer mainly composed of zinc oxide (ZnO), was formed on one main surface of the substrate by sputtering method, thereby obtaining a substrate with a conductive film.

[0099] More specifically, a soda-lime glass with a thickness of 3 mm (manufactured by AGC, FL3) was prepared as the substrate, and a protective layer mainly composed of ZnO (thickness: 45 nm) / a conductive layer mainly composed of Ag (thickness: 13 nm) / a protective layer mainly composed of ZnO (thickness: 90 nm) / a conductive layer mainly composed of Ag (thickness: 13 nm) / a protective layer mainly composed of ZnO (thickness: 30 nm) were sequentially formed on one main surface of the substrate by sputtering method as the conductive film, thereby obtaining a glass with a conductive film.

[0100] Here, the sheet resistance value of the conductive layer was 1.8 Ω / □.

[0101] Next, using a nanosecond laser (manufactured by Keyence, model MD-X1520), laser irradiation was performed from the surface of the substrate with the conductive film on the side where the conductive film was provided under the following conditions, thereby removing a part of the conductive film.

[0102] (Laser conditions)

[0103] The wavelength of the laser: 1064 nm, the pulse width: several tens of ns, the scanning speed of the laser was 300 mm / second, the frequency of the laser was 30 kHz, and the laser was scanned linearly.

[0104] (Example 2)

[0105] A femtosecond laser (manufactured by Light Conversion, model PHAROS-15) was used, the wavelength of the laser: 1064 nm, the pulse width: 237 fs, the scanning speed of the laser was 500 mm / second, the frequency of the laser was 100 kHz. Except for this, a substrate with a conductive film was produced according to the same operation steps as in Example 1.

[0106] (Observation of the oxide film)

[0107] For the substrate with a conductive film of Example 1 obtained above, a scanning electron microscope (SEM) (model S-4300, manufactured by HITACHI) was used to observe the presence and shape of the oxide film around the slit portion. The result of observing the surface of the substrate with a conductive film of Example 1 at an acceleration voltage of 5.0 kV is shown in Figure 3 in.

[0108] In Figure 3In [the figure], the white line corresponds to the oxide film 14, the central portion surrounded by the white line corresponds to the slit portion 13, and the upper and lower portions outside the white line correspond to the conductive film 12. In Example 1, at the end of the slit portion 13, it was observed that the oxide film 14 was continuously formed in the longitudinal direction of the slit portion 13.

[0109] In addition, for Example 2, the presence or absence of the oxide film around the slit portion was observed in the same operation steps as in Example 1, but it was confirmed that in Example 2, the oxide film was not continuously formed and was only formed in a part thereof.

[0110] <Average height of oxide film>

[0111] For the obtained substrate with a conductive film, using a stylus surface profiler (manufactured by Dektak, Bruker), the measurement length was set to 1 mm, and in any region including the conductive film / slit portion / conductive film, the height of the oxide film was measured based on the following conditions. In addition, the height of the oxide film at any three locations was measured by the same operation steps, and the average value thereof was taken as the average height of the oxide film. The results of Example 1 and Example 2 are shown in Table 1, Figure 4 and Figure 5 in.

[0112] (Measurement conditions)

[0113] Cutoff value λc: 0.8 mm, cutoff ratio λc / λs: 32, measurement speed: 0.1 mm / second.

[0114]

[0115] <Voltage application test>

[0116] For the obtained substrate with a conductive film, under the condition of dropping pure water at 25°C, a voltage of 5 V was applied for 60 minutes, and then the surface on the side where the conductive film was provided was observed with an optical microscope. The surface images of Example 1 and Example 2 observed with the optical microscope are shown in Figure 6 and Figure 7 in.

[0117] From Figure 6 and Figure 7 the results, it can be seen that in Example 1 as an embodiment, no dendrite formation was observed after the voltage application test, and excellent insulation was exhibited between the conductive films by forming the oxide film. In contrast, in Example 2 as a comparative example, the oxide film was not continuously formed and was only formed in a part. In addition, the height of the formed oxide film was low and the oxide film was thin. Therefore, the insulation was insufficient and dendrites were formed by the voltage application test. It should be noted that the average height of the oxide film in Example 2 was measured in the region where the oxide film was formed.

[0118] As described above, the following configurations are disclosed in this specification.

[0119] [1] A substrate with a conductive film, the substrate with a conductive film having a substrate and a conductive film formed on at least one main surface of the substrate, wherein the conductive film includes a conductive layer, the conductive film is isolated by slit portions, and at the ends of the conductive film isolated by the slit portions, the conductive layer is continuously covered by an oxide film.

[0120] [2] The substrate with a conductive film according to [1], wherein the conductive film includes a protective layer.

[0121] [3] The substrate with a conductive film according to [1] or [2], wherein the average height of the oxide film is 2 times or more the film thickness of the conductive film.

[0122] [4] The substrate with a conductive film according to any one of [1] to [3], wherein the conductive layer includes silver.

[0123] [5] The substrate with a conductive film according to any one of [1] to [4], wherein the substrate is glass.

[0124] [6] The substrate with a conductive film according to any one of [1] to [5], wherein the substrate is resin.

[0125] [7] A method for manufacturing a substrate with a conductive film, wherein a part of the conductive film is removed by irradiating a conductive film including a conductive layer formed on the surface of a substrate with a laser, so that the conductive film is isolated by slit portions and an oxide film continuously covering the conductive layer is formed at the ends of the conductive film isolated by the slit portions.

[0126] [8] The manufacturing method according to [7], wherein the pulse width of the laser is in picosecond or nanosecond level.

[0127] [9] The manufacturing method according to [7] or [8], wherein the wavelength of the laser is 500 nm to 1500 nm.

[0128]

[10] An electromagnetic wave control member, wherein the electromagnetic wave control member has the substrate with a conductive film according to any one of [1] to [6].

[0129]

[11] A radio wave absorber member, wherein the radio wave absorber member has the substrate with a conductive film according to any one of [1] to [6].

[0130]

[12] A frequency selective surface, wherein the frequency selective surface has the substrate with a conductive film according to any one of [1] to [6].

[0131] As described above, various embodiments have been explained, but the present invention is not limited to such examples. Those skilled in the art can obviously conceive of various variations or modifications within the scope described in the claims, and it should be understood that these also belong to the technical scope of the present invention. In addition, the constituent elements in the above embodiments can be arbitrarily combined without departing from the gist of the invention.

[0132] It should be noted that this application is based on a Japanese patent application filed on October 31, 2022 (Japanese Patent Application No. 2022-175050), the content of which is incorporated herein by reference.

[0133] Reference Numeral Explanation

[0134] 10 Substrate with Conductive Film

[0135] 11 Substrate

[0136] 12 Conductive Film

[0137] 13 Slit Portion

[0138] 14 Oxide Film

[0139] 15 Conductive Layer

[0140] 21, 22 Protective Layers

Claims

1. A substrate with a conductive film, the substrate with a conductive film having a substrate and a conductive film formed on at least one main surface of the substrate, wherein, the conductive film includes a conductive layer, the conductive film is isolated by slit portions, at the end of the conductive film isolated by the slit portions, the conductive layer is continuously covered with an oxide film.

2. The substrate with a conductive film according to claim 1, wherein, the conductive film includes a protective layer.

3. The substrate with a conductive film according to claim 1, wherein, the average height of the oxide film is 2 times or more of the film thickness of the conductive film.

4. The substrate with a conductive film according to claim 1, wherein, the conductive layer includes silver.

5. The substrate with a conductive film according to claim 1, wherein, the substrate is glass.

6. The substrate with a conductive film according to claim 1, wherein, the substrate is resin.

7. A method for manufacturing a substrate with a conductive film, wherein, a part of the conductive film is removed by irradiating a conductive film including a conductive layer formed on the surface of a substrate with a laser, so that the conductive film is isolated by slit portions and an oxide film continuously covering the conductive layer is formed at the end of the conductive film isolated by the slit portions.

8. The manufacturing method according to claim 7, wherein, the pulse width of the laser is in picosecond level or nanosecond level.

9. The manufacturing method according to claim 7 or 8, wherein, the wavelength of the laser is 500nm - 1500nm.

10. An electromagnetic wave control member, wherein, the electromagnetic wave control member has the substrate with a conductive film according to any one of claims 1 - 6.

11. A radio wave absorber member, wherein, the radio wave absorber member has the substrate with a conductive film according to any one of claims 1 - 6.

12. A frequency selective surface, wherein, the frequency selective surface has the substrate with a conductive film according to any one of claims 1 - 6.

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