JP2016216797A - Alloy target for sputtering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alloy target for sputtering for forming a blackened layer capable of performing an etching treatment simultaneously with a copper layer.SOLUTION: There is provided an alloy target for sputtering used for producing a conductive substrate for a touch panel including a blackened layer. The alloy target for sputtering produced by a dissolution method contains molybdenum as much as 2 atom% or more and 26 atom% or less, and nickel as much as 20 atom% or more and 80 atom% or less, and has a residue constituted of copper.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an alloy target for sputtering.

  A transparent conductive film for a touch panel in which an ITO (indium tin oxide) film is formed as a transparent conductive film on a polymer film has been conventionally used. (See Patent Document 1)

  By the way, in recent years, the display screen including a touch panel has been increased in screen size. Correspondingly, a conductive substrate such as a transparent conductive film for a touch panel is required to have a large area. However, since ITO has a high electric resistance value, there is a problem that it cannot cope with an increase in the area of the conductive substrate.

  For this reason, for example, as disclosed in Patent Documents 2 and 3, the use of a metal foil such as copper having excellent conductivity instead of the ITO film has been studied. However, for example, when copper is used for the wiring layer, since copper has a metallic luster, there is a problem that the visibility of the display decreases due to reflection.

  Therefore, in order to realize improvement of both the above-described characteristics of conductivity and visibility, a conductive substrate in which a blackened layer made of a black material is formed together with a wiring layer made of a metal foil such as copper is provided. It is being considered.

  However, in order to obtain a conductive substrate having a wiring pattern, it is necessary to form a desired pattern by etching the wiring layer and the blackened layer after forming the wiring layer and the blackened layer. There is a problem that the reactivity to the liquid is greatly different between the wiring layer and the blackened layer. That is, if the wiring layer and the blackened layer are simultaneously etched, one of the layers cannot be etched into the target shape.

JP 2003-151358 A JP 2011-018194 A JP 2013-0669261 A

  In view of the various problems of the prior art described above, an object of one aspect of the present invention is to provide a sputtering alloy target for forming a blackened layer that can be etched simultaneously with a copper layer.

In order to solve the above problems, in one aspect of the present invention,
An alloy target for sputtering used for producing a conductive substrate for a touch panel provided with a blackened layer,
Provided is a sputtering alloy target containing molybdenum in an amount of 2 atomic% or more and less than 26 atomic% and nickel in a ratio of 20 atomic% or more and less than 80 atomic%, with the balance being made of copper and manufactured by a melting method.

  According to one aspect of the present invention, it is possible to provide a sputtering alloy target for forming a blackened layer that can be etched simultaneously with a copper layer.

Sectional drawing of the electroconductive board | substrate which concerns on embodiment of this invention. Sectional drawing of the electroconductive board | substrate which concerns on embodiment of this invention. The top view of the electroconductive board | substrate provided with the mesh-shaped wiring which concerns on embodiment of this invention. Sectional drawing in the AA 'line of FIG. Structure explanatory drawing of the alloy target for sputtering produced in the Example.

(Alloy target for sputtering)
Hereinafter, one structural example of the alloy target for sputtering of the present invention will be described.

  The alloy target for sputtering of this embodiment is related with the alloy target for sputtering used for preparation of the conductive substrate for touchscreens provided with a blackening layer. And the alloy target for sputtering of this embodiment can contain molybdenum in the ratio of 2 atomic% or more and less than 26 atomic%, nickel in the ratio of 20 atomic% or more and less than 80 atomic%, and can comprise the remainder with copper, It can be produced by a melting method.

  The inventors of the present invention diligently studied a blackening layer provided to suppress reflection of light on the surface of a copper layer used as a wiring layer, which can be etched simultaneously with the copper layer. As a result, it has been found that an oxide film or an oxynitride film containing copper, nickel, and molybdenum simultaneously can be used as a blackening layer that can be etched simultaneously with the copper layer. And the oxide film and oxynitride film which contain the copper, nickel, and molybdenum simultaneously can be produced by sputtering.

  As a target used in the sputtering method, a molten alloy or a sintered body is mainly used. In particular, molten alloys are useful as sputtering targets because of their high density and uniformity.

  However, since copper and molybdenum do not dissolve, there is no known alloy target for sputtering containing an alloy composition suitable for forming the blackened layer and containing copper, nickel, and molybdenum produced by a melting method. It was. Therefore, the inventors of the present invention further studied and completed the present invention.

  First, the composition of the copper-nickel-molybdenum molten alloy used as the sputtering alloy target of the present embodiment will be described.

  The molybdenum content in the copper-nickel-molybdenum molten alloy is preferably 2 atomic percent or more and less than 26 atomic percent, and more preferably 2.5 atomic percent or more and less than 16 atomic percent.

  This is because if the molybdenum content is less than 2 atomic%, it may be difficult to control the optical characteristics required for the blackening layer constituting the conductive substrate for a touch panel, which is not preferable.

  Also, when the molybdenum content is 26 atomic% or more, after melting the metal raw material for producing a copper-nickel-molybdenum molten alloy, an undesired intermetallic compound is precipitated or melted during the cooling. May be separated into a Mo-rich phase and a copper-rich phase, resulting in an alloy having a non-uniform composition. When a blackened layer is formed by sputtering using an alloy having a non-uniform composition as a target, the blackened layer is not preferable because it does not become a film having a uniform composition and does not have excellent optical characteristics as a blackened layer for a touch panel. .

  In addition, it is more preferable because the composition of the copper-nickel-molybdenum molten alloy is more stable when the molybdenum content is less than 16 atomic%, and the compound layer does not precipitate even when hot rolled at about 1000 ° C., for example. .

  Next, the nickel content in the copper-nickel-molybdenum molten alloy is preferably 20 atomic percent or more and less than 80 atomic percent.

  This is because when the nickel content is less than 20 atomic%, the moisture resistance of the blackened layer obtained by sputtering film formation using the nickel may be unfavorable.

  Further, if the nickel content is 80 atomic% or more, the etching property is deteriorated, which is not preferable.

  The remainder of the copper-nickel-molybdenum molten alloy other than molybdenum and nickel can be made of copper.

  The mass ratio of molybdenum and nickel contained in the copper-nickel-molybdenum molten alloy as the sputtering alloy target of the present embodiment is not particularly limited, but the mass ratio of molybdenum and nickel is 2: It is preferable that it is 98 or more and 26:74 or less.

  That is, of the molybdenum and nickel contained in the copper-nickel-molybdenum molten alloy used as the sputtering alloy target of this embodiment, the proportion of molybdenum is preferably 2 atomic percent or more and 26 atomic percent or less.

  This is because, when the proportion of molybdenum is less than 2 atomic% among molybdenum and nickel contained in the copper-nickel-molybdenum molten alloy, the optical characteristics required as a blackening layer constituting the conductive substrate for touch panel are obtained. This is because it may be difficult to control. In addition, if the proportion of molybdenum exceeds 26 atomic% among molybdenum and nickel contained in the copper-nickel-molybdenum molten alloy, the composition of the copper-nickel-molybdenum molten alloy may become non-uniform. is there.

  The sputtering alloy target of this embodiment can be produced by a melting method. The melting method is a method in which copper, nickel, and molybdenum constituting the alloy target for sputtering are melted to form an alloy.

  However, as described above, copper and molybdenum are difficult to melt and do not dissolve. For this reason, it is preferable to produce the alloy target for sputtering according to the present embodiment by producing an alloy in which molybdenum is dissolved in nickel and melting the alloy and copper.

For this reason, in the alloy target for sputtering of this embodiment, it is preferable that molybdenum is dissolved in nickel.
(Manufacturing method of alloy target for sputtering)
Next, one structural example of the manufacturing method of the alloy target for sputtering of this embodiment is demonstrated.

  Copper and molybdenum are difficult to melt and do not dissolve. For this reason, according to a study by the inventors of the present invention, a copper-nickel-molybdenum molten alloy is prepared by preparing an alloy in which molybdenum is dissolved in nickel and melting the alloy and copper. Is preferred. Specifically, for example, it can be produced by the following procedure.

  First, a raw material preparation step for preparing a starting material can be performed.

  As starting materials, constituent components such as copper, nickel, and molybdenum can be prepared and weighed in accordance with the target composition of the sputtering alloy target.

  For example, in the case of producing a 46Cu-46Ni-8Mo molten alloy target, first, nickel is 46 atomic% (42.3 mass%), copper is 46 atomic% (45.7 mass%), and molybdenum is 8 atomic%. Weigh so that it becomes (12.0% by mass).

  Next, a nickel-molybdenum alloy forming step can be performed in which nickel and molybdenum are melted in a vacuum atmosphere to form a nickel-molybdenum alloy.

  In the nickel-molybdenum alloy forming step, nickel and molybdenum weighed in the raw material preparation step can be put in a crucible, for example, an alumina crucible, and heated and melted in a vacuum atmosphere to form a nickel-molybdenum alloy.

  In the nickel-molybdenum alloy formation step, heating can be performed using, for example, a vacuum melting furnace.

  The temperature for heating in the nickel-molybdenum alloy forming step is not particularly limited, and it is preferable to select the temperature so that molybdenum can be dissolved in nickel according to the composition of the nickel-molybdenum alloy to be formed. For example, when forming a nickel-molybdenum alloy for forming a 46Cu-46Ni-8Mo molten alloy, it is preferable to heat to 1550 ° C. or higher.

Note that from the phase diagram of molybdenum and nickel, it is possible to dissolve molybdenum in nickel up to 26 atomic% at 1315 ° C. In addition, it is possible to dissolve molybdenum in nickel at 875 ° C. where Ni ₄ Mo, which is an intermetallic compound of Ni and Mo, precipitates up to 16 atomic% of molybdenum and up to 13 atomic% of molybdenum at room temperature. I understand. Thus, it is preferable to select the heating temperature of the nickel-molybdenum alloy forming step based on the phase diagram and the composition of the alloy to be formed.

  Next, a copper-nickel-molybdenum alloy forming step can be performed in which copper is added to the molten nickel-molybdenum alloy formed in the nickel-molybdenum alloy forming step to form a copper-nickel-molybdenum molten alloy.

  After forming the nickel-molybdenum alloy in the melted state in the nickel-molybdenum alloy forming step, after confirming that the temperature was maintained for a certain period of time, for example, 5 minutes to 20 minutes, and completely dissolved, copper-nickel -It is preferable to start the molybdenum alloy formation step.

  In the copper-nickel-molybdenum alloy formation step, first, the nickel-molybdenum alloy is melted in the nickel-molybdenum alloy formation step, and an inert gas is put into a furnace maintained in a vacuum atmosphere so that the degree of vacuum is 50 Pa or more and 1000 Pa or less. It is preferable to adjust so that it becomes. The inert gas used at this time is not particularly limited. For example, argon gas, helium gas, or the like can be used.

  After introducing the inert gas into the furnace, the copper prepared in the raw material preparation process is poured into the crucible containing the melted nickel-molybdenum alloy several times, and the desired alloy composition is obtained by melting the copper. The copper-nickel-molybdenum molten alloy can be produced. If the temperature in the nickel-molybdenum alloy forming step is less than the melting point of copper, it is preferable to heat the copper to the melting point of copper or more before introducing the copper.

  Next, a vacuum heating step of heating under vacuum can be performed.

  After adding copper in the copper-nickel-molybdenum alloy forming step and melting the copper, a vacuum heating step can be performed. In the vacuum heating step, the furnace is evacuated again to degas the combined financial body, and after degassing, it is heated again in vacuum to obtain a uniform copper-nickel-molybdenum molten alloy. The heating conditions after degassing are not particularly limited. For example, it is preferable to heat and hold at a temperature of 1550 ° C. or more for 10 minutes or more.

  Next, an ingot forming process and a target processing process can be performed.

  After the vacuum heating step, an ingot forming step can be performed in which the molten copper-nickel-molybdenum alloy is poured into a mold to form an ingot. The mold is not particularly limited, and it may be made of a material that does not react with the copper-nickel-molybdenum alloy and has heat resistance with respect to the temperature of the molten copper-nickel-molybdenum alloy. For example, a carbon mold can be used.

  The ingot forming step is preferably performed in an inert gas atmosphere in order to suppress oxidation of the copper-nickel-molybdenum alloy.

  After the ingot forming step, the alloy target for sputtering according to the present embodiment can be obtained by performing the target processing step of cooling to room temperature and performing target processing.

By using the sputtering alloy target described above and the sputtering alloy target obtained by the sputtering alloy target manufacturing method, a blackened layer that can be etched simultaneously with the copper layer can be formed.
(Conductive substrate)
One structural example of a conductive substrate that can be manufactured using the sputtering alloy target of this embodiment will be described.

  By using the sputtering alloy target of this embodiment, a conductive substrate for a touch panel provided with a copper layer that can be simultaneously etched and a blackening layer can be suitably produced.

  The conductive substrate for a touch panel of the present embodiment is formed on a transparent base material, a copper layer formed on at least one surface side of the transparent base material, and at least one surface side of the transparent base material, oxygen, copper, A blackening layer containing nickel and molybdenum and containing 5 atomic% or more and 60 atomic% or less of oxygen (hereinafter also simply referred to as “blackening layer”) can be used.

  Heretofore, conductive substrates having various configurations have been studied as conductive substrates for touch panels. Among them, the use of a copper layer as a wiring layer of a conductive substrate has been studied, but since the copper layer has a metallic luster, the copper layer is formed only by forming a wiring obtained by etching the copper layer on a transparent substrate. Reflects light. For this reason, when it used as a conductive substrate for touch panels, for example, there was a problem that visibility of a display fell.

  For this reason, methods for providing a blackened layer have been studied, but the blackened layer may not have sufficient reactivity with the etching solution, and the copper layer and the blackened layer are etched into a desired shape at the same time. It was difficult to do.

  Therefore, the inventors of the present invention have studied, and since the layer containing oxygen, copper, nickel and molybdenum is black, it can be used as a blackening layer, and has sufficient reactivity with the etching solution. In order to show, it discovered that an etching process could be performed simultaneously with a copper layer.

Then, by using the sputtering alloy target of the present embodiment described above, it is possible to form a blackening layer containing oxygen, copper, nickel and molybdenum that can be etched simultaneously with the copper layer of the wiring layer and can be patterned at low cost. I found. Furthermore, when the blackening layer is formed using the sputtering alloy target of the present embodiment, good optical properties (for example, reflectance, lightness (L ^* ), chromaticity (a ^* , b) required for touch panels are used. It was also found that a blackened layer having ^* )) was obtained.

  Below, each layer contained in the electroconductive board | substrate of this embodiment is demonstrated.

  It does not specifically limit as a transparent base material, The insulator film which permeate | transmits visible light, a glass substrate etc. can be used preferably.

  As the insulator film that transmits visible light, for example, a polyamide film, a polyethylene terephthalate film, a polyethylene naphthalate film, a resin film such as a cycloolefin film, a polycarbonate film, or the like can be preferably used.

  It does not specifically limit about the thickness of a transparent base material, It can select arbitrarily according to the intensity | strength, electrostatic capacitance, light transmittance, etc. which are required when it is set as an electroconductive board | substrate.

  Next, the copper layer will be described.

  Although it does not specifically limit also about a copper layer, In order not to reduce the transmittance | permeability of light, it is preferable not to arrange | position an adhesive agent between a copper layer and a transparent base material, or between a blackening layer. That is, the copper layer is preferably formed directly on the upper surface of another member.

  In order to directly form the copper layer on the upper surface of the other member, the copper layer preferably has a copper thin film layer. Moreover, the copper layer may have a copper thin film layer and a copper plating layer.

  For example, a copper thin film layer can be formed on a transparent substrate or a blackened layer by a dry plating method, and the copper thin film layer can be used as a copper layer. Thereby, a copper layer can be formed directly on a transparent base material or a blackening layer, without passing an adhesive agent.

  The dry plating method used for forming the copper thin film layer is not particularly limited, and for example, a vacuum deposition method, a sputtering method, an ion plating method, or the like can be used. In particular, as the dry plating method used for forming the copper thin film layer, it is more preferable to use the sputtering method because the film thickness can be easily controlled.

  When the copper layer is thick, the copper thin film layer is used as a power feeding layer, and a copper plating layer is formed by a wet plating method to form a copper layer having a copper thin film layer and a copper plating layer. You can also. Since the copper layer has the copper thin film layer and the copper plating layer, the copper layer can be directly formed on the transparent substrate or the blackening layer without using an adhesive.

  The thickness of the copper layer is not particularly limited, and when the copper layer is used as a wiring, it can be arbitrarily selected according to the magnitude of the current supplied to the wiring, the wiring width, and the like. In particular, the thickness of the copper layer is preferably 100 nm or more, and more preferably 150 nm or more so that sufficient current can be supplied. The upper limit value of the thickness of the copper layer is not particularly limited, but if the copper layer becomes thick, side etching occurs because etching takes time when performing etching to form a wiring, and the resist peels off during the etching. Etc. are likely to occur. For this reason, it is preferable that the thickness of a copper layer is 3 micrometers or less, and it is more preferable that it is 700 nm or less.

  In addition, when a copper layer has a copper thin film layer and a copper plating layer as mentioned above, it is preferable that the sum total of the thickness of a copper thin film layer and the thickness of a copper plating layer is the said range.

  Next, the blackened layer will be described.

  The blackening layer can be formed by the sputtering method using the sputtering alloy target of this embodiment and supplying oxygen as a reactive gas in the chamber. In addition, a mixed gas of oxygen and nitrogen can be used as the reactive gas. In this case, the film can be formed by a sputtering method while supplying oxygen and nitrogen into the chamber.

  The content ratio of oxygen in the gas supplied into the chamber at the time of sputtering is not particularly limited, but a blackening layer is formed while supplying a gas having an oxygen content ratio of 5 volume% or more and 45 volume% or less to the chamber. It is preferable.

This is because the reactivity of the blackened layer with respect to the etching solution can be particularly increased by setting the oxygen content in the gas supplied into the chamber to 45% by volume or less. For this reason, when etching a blackening layer with a copper layer, a copper layer and a blackening layer can be easily made into a desired pattern, and it is preferable. Furthermore, the reflectance, lightness (L ^* ), and chromaticity (a ^* , b ^* ) of the optical properties are all preferable as a blackened layer.

In particular, from the viewpoint of making the chromaticity (a ^* , b ^* ) particularly good as a blackened layer, the supply ratio of oxygen in the gas supplied into the chamber is more preferably 42% by volume or less.

  In addition, by setting the content ratio of oxygen in the gas supplied into the chamber at the time of sputtering to 5% by volume or more, the color of the formed blackened layer is particularly suppressed in suppressing the reflection of light on the surface of the copper layer. A suitable color can be obtained, which is preferable.

  As described above, a mixed gas of oxygen and nitrogen can be used as the reactive gas. By using a mixed gas of oxygen and nitrogen as the reactive gas, the etching property of the blackened layer can be particularly improved. When a mixed gas of oxygen and nitrogen is used as the reactive gas, the ratio of oxygen to nitrogen is preferably 1: 4 or more and 5: 5 or less by volume. That is, it is preferable that the ratio of oxygen in the mixed gas of oxygen and nitrogen is 20 volume% or more and 50 volume% or less.

  Note that when sputtering is performed, the gas supplied into the chamber is preferably an inert gas for the remainder other than oxygen or a mixed gas of oxygen and nitrogen. For the remainder other than oxygen or a mixed gas of oxygen and nitrogen, it is preferable to use one or more gases selected from, for example, argon, xenon, neon, and helium.

  The formed blackening layer can contain oxygen, copper, nickel, and molybdenum. When the total content of copper, nickel and molybdenum contained in the blackened layer, that is, the total content of metal elements is 100 atomic%, the molybdenum content is 2 atomic% or more and 70% atomic or less. It is preferable.

  This is because the reflectance of light on the surface of the blackened layer can be particularly lowered by setting the molybdenum content in the metal element contained in the blackened layer to 2 atomic% or more. Then, by making the content of molybdenum in the metal element contained in the blackened layer 70 atomic% or less, the blackened layer exhibits high etching properties and easily produces a conductive substrate having a desired pattern. It is because it can do.

  In addition, by forming the blackened layer using the sputtering alloy target of the present embodiment described above, the molybdenum content in the metal element contained in the blackened layer can be easily adjusted to the above range. .

  Further, the oxygen contained in the blackened layer is preferably 5 atomic percent or more and 60 atomic percent or less, more preferably 20 atomic percent or more and 55 atomic percent or less, among the components contained in the blackened layer. .

  This is because the blackening layer becomes translucent due to the oxygen content in the blackening layer being 5 atomic% or more, so that the black can be made sufficiently black due to the light interference effect, and light reflection is particularly suppressed. This is because it can. Further, if the oxygen content in the blackened layer is more than 60 atomic%, the etching property of the blackened layer may be lowered, and the sheet resistance of the blackened layer is increased. preferable.

  Although the thickness of a blackening layer is not specifically limited, For example, it is preferable that it is 20 nm or more, and it is more preferable to set it as 25 nm or more. The blackening layer is black as described above and functions as a blackening layer that suppresses reflection of light by the copper layer. However, when the thickness of the blackening layer is thin, sufficient blackness is obtained. In some cases, reflection of light by the copper layer cannot be sufficiently suppressed. On the other hand, since the reflection of a copper layer can be suppressed more by making the thickness of a blackening layer into the said range, it is preferable.

The upper limit of the thickness of the blackened layer is not particularly limited, but when the thickness of the blackened layer is increased, the reflectance, lightness (L ^* ), and chromaticity (a ^* , b ^* ) of the optical characteristics are increased. May be inferior in characteristics as a blackened layer, which is not preferable. For this reason, the thickness of the blackened layer is preferably 45 nm or less, and more preferably 40 nm or less.

  Next, a configuration example of the conductive substrate of this embodiment will be described.

  As described above, the conductive substrate of this embodiment includes a transparent base material, a copper layer, and a blackening layer. Under the present circumstances, the order of lamination | stacking at the time of arrange | positioning a copper layer and a blackening layer on a transparent base material is not specifically limited. Further, a plurality of copper layers and blackening layers can be formed. In order to suppress the reflection of light on the surface of the copper layer, it is preferable that the blackening layer is disposed on the surface of the copper layer on which the reflection of light is particularly desired to be suppressed. More preferably, the copper layer has a structure sandwiched between blackening layers.

  A specific configuration example will be described below with reference to FIGS. 1 and 2 show examples of cross-sectional views of the conductive substrate of this embodiment on a plane parallel to the lamination direction of the transparent base material, the copper layer, and the blackening layer.

  For example, as in the conductive substrate 10A shown in FIG. 1A, the copper layer 12 and the blackening layer 13 can be laminated one layer at a time on the one surface 11a side of the transparent base material 11. . Moreover, like the electroconductive board | substrate 10B shown in FIG.1 (b), copper layer 12A, 12B on the one surface 11a side of the transparent base material 11, and the other surface (other surface) 11b side, respectively. And the blackening layers 13A and 13B can be stacked one by one in that order. In addition, the order which laminates | stacks the copper layer 12 (12A, 12B) and the blackening layer 13 (13A, 13B) is not limited to the example of Fig.1 (a), (b), From the transparent base material 11 side. The blackening layer 13 (13A, 13B) and the copper layer 12 (12A, 12B) can be laminated in this order.

  In addition, for example, a configuration in which a plurality of blackening layers are provided on the one surface 11 a side of the transparent substrate 11 may be employed. For example, like the conductive substrate 20A shown in FIG. 2A, the first blackened layer 131, the copper layer 12, and the second blackened layer 132 are formed on the one surface 11a side of the transparent substrate 11. Can be stacked in that order.

  In this case as well, a configuration in which a copper layer, a first blackened layer, and a second blackened layer are laminated on both surfaces of the transparent substrate 11 can be adopted. Specifically, as in the conductive substrate 20B shown in FIG. 2B, the first surface 11a side of the transparent base material 11 and the other surface (the other surface) 11b side are respectively first. Blackening layers 131A and 131B, copper layers 12A and 12B, and second blackening layers 132A and 132B can be stacked in that order.

  In FIGS. 1B and 2B, when a copper layer and a blackening layer are laminated on both surfaces of the transparent base material, the transparent base material 11 serves as a symmetrical surface and the top and bottom of the transparent base material 11 are aligned. Although the example which arrange | positioned so that the laminated | stacked layer might become symmetrical was shown, it is not limited to the form which concerns. For example, in FIG. 2B, the configuration on the one surface 11a side of the transparent substrate 11 is formed by laminating the copper layer 12 and the blackening layer 13 in that order, similarly to the configuration of FIG. The layers laminated on the top and bottom of the transparent substrate 11 may be asymmetrical.

  Up to this point, the conductive substrate of the present embodiment has been described. However, in the conductive substrate of the present embodiment, the copper layer and the blackened layer are provided on the transparent base material. Reflection can be suppressed.

  The degree of light reflection of the conductive substrate of the present embodiment is not particularly limited. For example, the conductive substrate of the present embodiment preferably has a reflectance of 30% or less, and 20% or less for light having a wavelength of 550 nm. More preferably, it is more preferably 10% or less.

  The visible light average reflectance, which is the average reflectance for light in the wavelength range of 350 nm to 780 nm, is preferably 30% or less, more preferably 20% or less, and more preferably 10% or less. Particularly preferred.

  This is because, when at least one of the reflectance for light having a wavelength of 550 nm and the average reflectance of visible light is 30% or less, even when used as a conductive substrate for a touch panel, for example, the visibility of the display is hardly lowered. is there. From the viewpoint of particularly suppressing a reduction in the visibility of the display, both the reflectance with respect to light having a wavelength of 550 nm and the average reflectance of visible light are more preferably 30% or less.

  The reflectance can be measured by irradiating the blackened layer with light. That is, measurement can be performed from the blackened layer side of the copper layer and the blackened layer included in the conductive substrate.

  Specifically, for example, when the copper layer 12 and the blackened layer 13 are laminated in this order on one surface 11a of the transparent substrate 11 as shown in FIG. 1A, the blackened layer 13 can be irradiated with light. Measurement can be performed by irradiating the surface A with light.

  Further, in the case of FIG. 1A, the arrangement of the copper layer 12 and the blackened layer 13 is changed, and when the blackened layer 13 and the copper layer 12 are laminated in this order on one surface 11a of the transparent base material 11, The reflectance can be measured by irradiating light from the surface 11b side of the transparent substrate 11, which is the side where the blackened layer 13 is located on the outermost surface except the material 11.

  As will be described later, the conductive substrate can form wiring by etching the copper layer and the blackened layer, but the reflectance is arranged on the outermost surface when the transparent substrate is removed from the conductive substrate. The reflectance of the blackened layer on the surface on the light incident side is shown. For this reason, if it is before an etching process or after performing an etching process, it is preferable that the measured value in the part in which the copper layer and the blackening layer remain satisfy | fills the said range.

Further, lightness (L ^* ) and chromaticity (a ^* , b ^* ) can be calculated from the measured reflectance. The lightness (L ^* ) and chromaticity (a ^* , b ^* ) are not particularly limited, but the lightness (L ^* ) is preferably 60 or less, and more preferably 55 or less. Further, at least one of the chromaticities (a ^* , b ^* ) is preferably less than 0, that is, negative, and more preferably, both a ^* and b ^* are less than 0.

This is because when the lightness (L ^* ) is 60 or less, the color tone becomes dark, so that reflection of light can be particularly suppressed. Further, when at least one of the chromaticities (a ^* , b ^* ) is less than 0, the blackened layer becomes a color particularly suitable for suppressing light reflection.

  As described above, the conductive substrate of this embodiment can be preferably used as a conductive substrate for a touch panel, for example. In this case, the conductive substrate can be configured to have mesh-like wiring.

  The conductive substrate provided with the mesh-like wiring can be obtained by etching the copper layer and the blackening layer of the conductive substrate of the present embodiment described so far.

  For example, a two-layer wiring can be used as a mesh wiring. A specific configuration example is shown in FIG. FIG. 3 shows a view of the conductive substrate 30 provided with mesh-like wiring as viewed from the upper surface side in the stacking direction of the copper layer and the blackened layer. The conductive substrate 30 shown in FIG. 3 has a transparent base material 11, a plurality of wirings 31A parallel to the Y-axis direction in the drawing, and wirings 31B parallel to the X-axis direction. The wirings 31A and 31B are formed by etching a copper layer, and a blackening layer (not shown) is formed on the upper surface and / or the lower surface of the wirings 31A and 31B. The blackened layer is etched in the same shape as the wirings 31A and 31B.

  The arrangement of the transparent substrate 11 and the wirings 31A and 31B is not particularly limited. An example of the arrangement of the transparent substrate 11 and the wiring is shown in FIGS. 4A and 4B correspond to cross-sectional views taken along line AA ′ of FIG.

  First, as shown to Fig.4 (a), wiring 31A, 31B may be arrange | positioned at the upper and lower surfaces of the transparent base material 11, respectively. In this case, blackened layers 32A and 32B etched in the same shape as the wiring are disposed on the upper surface of the wiring 31A and the lower surface of the wiring 31B, respectively.

  Further, as shown in FIG. 4B, a pair of transparent base materials 11A and 11B are used, and wirings 31A and 31B are arranged on the upper and lower surfaces with one transparent base material 11A interposed therebetween, and one wiring 31B may be disposed between the transparent substrate 11A and the transparent substrate 11B. Also in this case, blackened layers 32A and 32B etched in the same shape as the wiring are disposed on the upper surfaces of the wirings 31A and 31B. As described above, the arrangement of the blackened layer and the copper layer is not limited. For this reason, in any of FIGS. 4A and 4B, the arrangement of the blackening layers 32A and 32B and the wirings 31A and 31B can be reversed upside down. For example, a plurality of blackening layers can be provided.

  However, the blackening layer is preferably disposed on the surface of the copper layer surface where light reflection is particularly desired to be suppressed. For this reason, in the conductive substrate shown in FIG. 4B, for example, when it is necessary to suppress the reflection of light from the lower surface side in the figure, the positions of the blackening layers 32A and 32B, the wiring 31A, It is preferable to reverse the positions of 31B. Further, in addition to the blackening layers 32A and 32B, a blackening layer may be further provided between the wiring 31A and the transparent base material 11A and / or between the wiring 31B and the transparent base material 11B.

  The conductive substrate having the mesh-like wiring shown in FIG. 3 and FIG. 4A includes, for example, copper layers 12A and 12B on both surfaces of the transparent substrate 11 as shown in FIG. 1B and FIG. And a blackened layer 13A, 13B (131A, 132A, 131B, 132B).

  The case where it is formed using the conductive substrate of FIG. 1B will be described as an example. First, the copper layer 12A and the blackened layer 13A on the one surface 11a side of the transparent base material 11 are shown in FIG. Etching is performed so that a plurality of linear patterns parallel to the Y-axis direction are arranged at predetermined intervals along the X-axis direction. The X-axis direction in FIG. 1 (b) means a direction parallel to the width direction of each layer in FIG. 1 (b). Further, the Y-axis direction in FIG. 1B means a direction perpendicular to the paper surface.

  A plurality of linear patterns parallel to the X-axis direction in FIG. 1B are predetermined along the Y-axis direction on the copper layer 12B and the blackening layer 13B on the other surface 11b side of the transparent substrate 11. Etching is performed so as to be spaced apart from each other.

  Through the above operation, the conductive substrate having the mesh-like wiring shown in FIGS. 3 and 4A can be formed. Note that the etching of both surfaces of the transparent substrate 11 can be performed simultaneously. That is, the etching of the copper layers 12A and 12B and the blackening layers 13A and 13B may be performed simultaneously.

  The method for etching the copper layer and the blackened layer into a desired shape is not particularly limited. For example, etching can be performed by the following procedure. First, a resist having an opening corresponding to a portion to be removed by etching is formed on the outermost surface of the conductive substrate. In the case of the conductive substrate shown in FIG. 1B, a resist can be formed on the exposed surfaces A and B of the blackening layers 13A and 13B arranged on the conductive substrate. Note that a method for forming a resist having an opening corresponding to a portion to be removed by etching is not particularly limited. For example, the resist can be formed by a photolithography method.

  Next, etching of the copper layers 12A and 12B and the blackening layers 13A and 13B can be performed by supplying an etching solution from the upper surface of the resist.

  Since the blackened layer shows almost the same reactivity to the etching solution as the copper layer, the etching solution used for etching is not particularly limited, and is generally an etching solution used for etching the copper layer. Can be preferably used. As the etching solution, for example, a mixed aqueous solution of ferric chloride and hydrochloric acid can be used more preferably. The contents of ferric chloride and hydrochloric acid in the etching solution are not particularly limited. For example, ferric chloride is preferably contained in a proportion of 5% by mass to 50% by mass, and 10% by mass. More preferably, it is contained at a ratio of 30% by mass or less. Further, for example, the etching solution preferably contains hydrochloric acid in a proportion of 1% by mass or more and 50% by mass or less, and more preferably contains 1% by mass or more and 20% by mass or less. The remainder can be water.

  Although the etching solution can be used at room temperature, it is preferably heated to increase the reactivity, and for example, it is preferably heated to 40 ° C. or more and 50 ° C. or less.

  The conductive substrate having the mesh-like wiring shown in FIG. 3 can also be formed by using two conductive substrates shown in FIG. 1 (a) or FIG. 2 (a). The case where the conductive substrate of FIG. 1A is used will be described as an example. For the two conductive substrates shown in FIG. 1A, the copper layer 12 and the blackened layer 13 are parallel to the X-axis direction, respectively. Etching is performed so that a plurality of linear patterns are arranged at predetermined intervals. Then, the conductive substrate having mesh-like wiring is obtained by bonding the two conductive substrates so that the linear patterns formed on the respective conductive substrates intersect with each other by the etching process. be able to. The surface to be bonded when the two conductive substrates are bonded is not particularly limited. The surface A in FIG. 1A in which the copper layer 12 or the like is laminated as shown in FIG. The surface 11b in FIG. 1A on which the layer 12 and the like are not stacked may be bonded.

  In addition, it is preferable that the blackening layer is arrange | positioned in the surface which wants to suppress especially reflection of light among the copper layer surfaces. Therefore, in the conductive substrate shown in FIG. 4B, when it is necessary to suppress the reflection of light from the lower surface side in the figure, the positions of the blackening layers 32A and 32B and the wirings 31A and 31B It is preferable to arrange the positions in reverse. Further, in addition to the blackening layers 32A and 32B, a blackening layer may be further provided between the wiring 31A and the transparent base material 11A and / or between the wiring 31B and the transparent base material 11B.

  Further, for example, the surfaces 11b in FIG. 1A on which the copper layer 12 or the like of the transparent substrate 11 is not laminated may be bonded together so that the cross section has the structure shown in FIG. .

  Note that the width of the wiring and the distance between the wirings in the conductive substrate having the mesh-like wiring shown in FIGS. 3 and 4 are not particularly limited, and are selected according to, for example, the amount of current flowing through the wiring. can do.

  3 and 4 show an example in which a mesh-like wiring (wiring pattern) is formed by combining linear wirings, but the present invention is not limited to such a configuration, and a wiring pattern is configured. The wiring can have any shape. For example, the shape of the wiring constituting the mesh-like wiring pattern can be changed to various shapes such as jagged lines (zigzag straight lines) so that moire (interference fringes) does not occur between the images on the display.

  Thus, a conductive substrate having a mesh-like wiring composed of two layers of wiring can be preferably used as a conductive substrate for a projected capacitive touch panel, for example.

  In the conductive substrate of this embodiment, a blackened layer can be formed using the sputtering target of this embodiment. For this reason, since the copper layer and the blackened layer show almost the same reactivity with the etching solution, the etching process can be performed simultaneously, and a desired wiring can be easily formed. Further, since the blackened layer is black, reflection of light by the copper layer can be suppressed, and for example, when a conductive substrate for a touch panel is used, a reduction in visibility can be suppressed.

Specific examples and comparative examples will be described below, but the present invention is not limited to these examples.
[Example 1]
In Example 1, a sputtering alloy target having an alloy composition of 46Cu-46Ni-8Mo was prepared by a melting method according to the following procedure.

  As a raw material preparation step, constituent components of copper, nickel, and molybdenum as starting materials were prepared.

  First, the metallic nickel is 46 atomic% (5070 g, 42.3 mass%), the metallic copper is 46 atomic% (5490 g, 45.7 mass%), and the metallic molybdenum is 8 atomic% (1441 g, 12 mass%). Weighed out. In addition, as for metallic nickel, metallic copper, and metallic molybdenum, button-shaped ingots and plates were used.

  Subsequently, the nickel-molybdenum alloy formation process was implemented.

  The metal nickel and metal molybdenum prepared in the raw material preparation step were filled in an alumina crucible and installed in a vacuum melting furnace (manufactured by Fuji Denpa Kogyo). The vacuum melting furnace was evacuated and heated to 1550 ° C. In addition, 1550 degreeC which is heating temperature was previously calculated | required from the phase diagram so that the composition of the target nickel-molybdenum alloy could be formed reliably.

  Next, a copper-nickel-molybdenum alloy forming step was performed.

  The copper-nickel-molybdenum alloy forming step was carried out after the nickel-molybdenum alloy forming step reached 1550 ° C. and then held at 1550 ° C. for 10 minutes to confirm complete dissolution.

  In starting the copper-nickel-molybdenum alloy forming step, first, the nickel-molybdenum alloy is melted in the nickel-molybdenum alloy forming step, and Ar gas is put in a vacuum melting furnace maintained in a vacuum atmosphere so that the degree of vacuum becomes 500 Pa. It adjusted so that it might become.

  After that, 5490 g of metal copper prepared in the raw material preparation step was put into the crucible in four times into the crucible containing the melted nickel-molybdenum alloy.

  Next, the vacuum heating process was implemented.

  In the vacuum heating process, first, in the copper-nickel-molybdenum alloy formation process, metal copper is introduced into the crucible, and after the copper has melted, the vacuum melting furnace is evacuated to degas the financial body. It was. And after degassing, it heated again in the vacuum and it hold | maintained at 1550 degreeC or more and 1650 degrees C or less for 10 minutes.

  The ingot formation process was implemented after the vacuum heating process.

  In the ingot forming step, a copper-nickel-molybdenum alloy in a melted state, which has been subjected to a vacuum heating step, is poured into a carbon mold (150 × 50 × 150 mm) in an argon gas atmosphere to ingot (150 × 50 × 110 mm).

  After the ingot forming step, the obtained copper-nickel-molybdenum alloy ingot was cooled to room temperature, and the hardness of the surface of the ingot was measured with Micro Vickers (manufactured by Matsuzawa Seisakusho: DMH-1). Any five points on the surface of the ingot were measured, and it was confirmed that the average hardness was 170 Hv.

  Moreover, about the obtained ingot, SEM-EDS (SEM: JEOL Co., Ltd. model: JSM-7001F, EDS: Thermo Fisher Scientific Co., Ltd. model: Detector UltraDry analysis system NORAN System 7) is analyzed. As a result, it was confirmed that molybdenum was dissolved in nickel.

  Next, the target processing process which processes into the alloy target for sputtering using the obtained ingot was implemented.

  A 110 × 60 × 50 mm plate was cut out from the obtained ingot and rolled hot (1000 ° C.) to produce a plate rolled to 110 × 150 × 22 mm. The rolling pass was repeated 5 times with heating.

  A disc having a diameter of 75 mm and a thickness of 6 mm was cut out from the rolled plate. Then, the surface of the disk was ground to obtain a flat surface to obtain a sputtering alloy target.

  The obtained sputtering alloy target was bonded to a copper backing plate using an In (indium) brazing agent so as to be mounted on a sputtering apparatus.

  Therefore, a target having the structure shown in FIG. 5 was obtained. FIG. 5A shows a top view of the produced sputtering alloy target as seen from the surface on the sputtering alloy target side. FIG. 5B shows a cross-sectional view along the line AA.

As shown in FIG. 5A, the sputtering alloy target 52 is arranged on the backing plate 51 in a substantially concentric shape. As shown in FIG. 5B, a bonding layer 53 made of an indium brazing agent is provided between the backing plate 51 and the sputtering alloy target 52.
(Preparation of conductive substrate)
In order to evaluate the performance of the produced sputtering alloy target, a conductive substrate including a blackened layer was produced. A conductive substrate sample in which a copper layer and a blackening layer containing oxygen, copper, nickel and molybdenum were formed on a PET substrate (polyethylene terephthalate substrate) was produced. That is, a conductive substrate having the same cross-sectional structure as the conductive substrate shown in FIG.

  First, a transparent substrate 11 made of polyethylene terephthalate resin (PET, trade name “Lumirror U48”, manufactured by Toray Industries, Inc.) having a length of 6 cm, a width of 6 cm, and a thickness of 0.05 mm was prepared.

  Next, a copper layer 12 as a copper thin film layer was formed on one surface of the transparent substrate 11 by direct current sputtering so that the film thickness was 250 nm.

  Next, a blackening layer 13 was formed on the surface of the copper layer 12 opposite to the surface facing the transparent substrate 11. The blackening layer 13 was formed using a sputtering apparatus (Model: SIH-450 manufactured by ULVAC, Inc.).

  Specific conditions for sputtering will be described below.

  As a target, a target including a sputtering alloy target containing 46 atomic% of nickel, 46 atomic% of copper, and 8 atomic% of molybdenum prepared in this example was used.

  Before performing sputtering, the inside of the chamber was evacuated, and then sputtering was performed while supplying oxygen gas and argon gas into the chamber.

The ultimate vacuum in the chamber when the chamber was evacuated was 1.5 × 10 ⁻⁴ Pa.

  Further, after the vacuum is reached, the oxygen gas and the argon gas are supplied at a flow rate of 6 sccm and 14 sccm when supplying oxygen gas and argon gas, respectively, and sputtering is performed while supplying a total of 20 sccm. It was. That is, the content ratio of oxygen in the gas supplied into the chamber was 30% by volume.

  Then, a blackened layer was formed so as to have a DC power of 200 W applied to sputtering and a film thickness of 30 nm, and a conductive substrate was prepared (Sample 1).

In addition, a conductive substrate was prepared in the same manner as Sample 1 except that the sputtering time was changed so that the film thickness was 35 nm after the copper layer was prepared in the same manner (Sample 2).
(Evaluation of conductive substrate)
(1) Evaluation of blackened layer The optical characteristics of the blackened layer of the obtained conductive substrate were evaluated.

  The reflectance was measured by installing a reflectance measurement unit in an ultraviolet-visible spectrophotometer (Hitachi High-Technologies Corporation model: U-4000).

  As described above, the conductive substrate used for the measurement has the same structure as that shown in FIG. Therefore, with respect to the surface A in FIG. 1A on the side where the copper layer and blackening layer of the produced conductive substrate are formed, the incident angle is 12 ° and the light receiving angle is 12 °, and the wavelength ranges from 350 nm to 780 nm. The reflectance when irradiated with light was measured. In the measurement, light having a wavelength changed every 1 nm was irradiated in a wavelength range of 350 nm or more and 780 nm or more, and the reflectance for each wavelength was measured.

  And the average value of the reflectance with respect to the light whose wavelength is 350 nm or more and 780 nm or less was made into the visible light average reflectance. Moreover, the measured value of the reflectance with respect to light having a wavelength of 550 nm was defined as the reflectance with respect to light having a wavelength of 550 nm.

  In the measurement, in order to correct the warp of the PET film, the sample was placed on a glass substrate, fixed with a clamp, and irradiated with light from the blackened layer side.

Calculate coordinates in the CIE 1976 (L ^* , a ^* , b ^* ) color space from the measured reflectance using a color calculation program based on JIS Z8781-4: 2013 under conditions of light source A and field of view of 2 degrees. did.

The measurement results are shown in Table 1. From Table 1, it was confirmed that the lightness (L ^* ) of both the blackened layers of Sample 1 and Sample 2 was as low as 40 or less. Further, both the blackened layers of Sample 1 and Sample 2 had negative chromaticity (a ^* , b ^* ) values, and it was confirmed that the blackened layer was a bluish black film. From these results, it was confirmed that the blackened layers formed by Sample 1 and Sample 2 were sufficiently usable as a blackened layer for a touch panel.

（２）溶解性試験
次いで、黒化層の溶解性試験を行った。

(2) Solubility test Next, the solubility test of the blackened layer was performed.

  In carrying out the solubility test, a sample for the solubility test was prepared.

  On the same PET film as when the conductive substrate was produced, the copper substrate was not provided, but only the blackened layer was formed and the thickness of the blackened layer was changed. In the same manner as the case, a sample for solubility test was prepared.

  Note that in the sample for the solubility test, the blackened layer has a thickness of 300 nm, and the sputtering conditions are the same as in the case where the sample 1 of the conductive substrate is manufactured.

  In the solubility test, the above-described sample for solubility test was immersed in an etching solution, and the time until the blackened layer was completely melted was evaluated. As an etching solution, an aqueous solution having 10% by weight of ferric chloride, 10% by weight of hydrochloric acid, the balance being water and a liquid temperature of 20 ° C. was used.

  In order to prescribe the evaluation of the solubility test, a sample in which a copper layer having a thickness of 300 nm is formed on the same surface of one surface of the same PET film as when the sample for the solubility test was prepared is immersed in the same etching solution. A preliminary experiment was conducted. In this case, it was confirmed that the copper layer was dissolved within 10 seconds. Therefore, if the blackened layer dissolves within 1 minute, it can be said that the blackened layer has the same etching property as the copper layer, and the blackened layer that can be etched simultaneously with the copper layer. It can be said that a layer is formed.

  And as a result of performing the solubility test about the said sample for a solubility test, the blackening layer melt | dissolved the whole quantity within 1 minute, It has confirmed that it had favorable etching property.

  From the above results, it was confirmed that the blackened layer formed using the sputtering alloy target prepared in this example showed sufficient reactivity with the etching solution. Therefore, it was confirmed that the copper layer and the blackened layer can be simultaneously etched when the copper layer and the blackened layer are stacked as the conductive substrate.

52 Alloy Target for Sputtering

Claims (3)

An alloy target for sputtering used for producing a conductive substrate for a touch panel provided with a blackened layer,
An alloy target for sputtering, which contains molybdenum in a proportion of 2 atomic percent to less than 26 atomic percent and nickel in a proportion of 20 atomic percent to less than 80 atomic percent, the balance being made of copper, and produced by a melting method.   The alloy target for sputtering according to claim 1, wherein the mass ratio of molybdenum to nickel is from 2:98 to 26:74.   The alloy target for sputtering according to claim 1 or 2, wherein molybdenum is dissolved in nickel.

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