TW202200816A - Sputtering target and optical functional film - Google Patents

Abstract

A sputtering target comprising a first component including a carbide of at least one selected from W and Ta and a second component of an oxide of at least one selected from Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo, and W, wherein the total contained amount of W and Ta in the first component is within a range of 10-35 atom%.

Description

Sputtering targets and optical functional films

The present invention relates to a sputtering target and an optical functional film used for forming an optical functional film which is laminated on a metal thin film or the like and reduces reflection of light from the metal thin film or the like. This case claims priority based on Japanese Patent Application No. 2020-093236 filed in Japan on May 28, 2020 and Japanese Patent Application No. 2021-086830 filed in Japan on May 24, 2021, the contents of which are incorporated herein.

In recent years, projection-type capacitive touch panels have been used as input means for mobile devices and the like. In the touch panel of this type, electrodes for sensing are formed in order to detect the touch position. The electrodes for sensing are usually formed by patterning, and an X electrode extending in the X direction and a Y electrode extending in the Y direction orthogonal to the X direction are provided on one surface of the transparent substrate, and these are arranged. grid-like. Here, when a metal thin film is used for the electrodes of the touch panel, since the metal thin film has metallic luster, the pattern of the electrodes can be recognized from the outside. For this reason, it is considered to reduce the visibility of the electrode by forming a low reflectance film with low reflectance of visible light on the metal thin film.

In addition, in flat panel displays represented by liquid crystal display devices and plasma displays, color filters for color display are used. In this color filter, a black member called a black matrix is formed in order to optimize contrast and color purity and improve visibility. The above-mentioned low reflectance film can also be used as this black matrix (hereinafter referred to as "BM").

In addition, in a solar panel, when sunlight is incident through a glass substrate or the like, the back surface electrode of the solar cell is formed on the opposite side. As this back electrode, a metal thin film of molybdenum (Mo), silver (Ag), or the like is used. When the solar panel in such a state is viewed from the back side, the metal thin film serving as the back electrode can be recognized. For this reason, it is considered to form the above-mentioned low reflectivity film on the back surface electrode to reduce the visibility of the back surface electrode.

Here, the laminated film of the above-mentioned wiring film and the low-reflectance film is patterned by etching, as described in, for example, Patent Documents 1 and 2. Moreover, in patent document 1, patterning is implemented using the etching liquid containing hydrogen peroxide.

However, the laminated film of the above-mentioned wiring film and the low-reflectance film may be subjected to, for example, a heat treatment at about 400° C. in the subsequent procedure. For this reason, heat resistance such that optical properties are not deteriorated by heat treatment at about 400° C. is required. In addition, as described above, the laminated film of the wiring film and the low-reflectance film is patterned by etching, and therefore, it is required to be excellent in etching properties.

Here, the low reflectance film described in Patent Document 1 is excellent in etching properties by an etching solution containing hydrogen peroxide, but is insufficient in heat resistance. In addition, the low-reflectivity film described in Patent Document 2 is excellent in heat resistance by using a copper oxynitride film (CuNO film), but the etching property by an etching solution containing hydrogen peroxide is insufficient. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2015-130007 [Patent Document 2] Japanese Patent Laid-Open No. 2016-186928

[Problems to be Solved by Invention]

In this aspect of the present invention, the inventors have been made in view of the above-mentioned circumstances, and an object is to provide an optical functional film which is excellent in etching resistance and heat resistance by an etching solution containing hydrogen peroxide, and which can sufficiently suppress reflection of light from a metal thin film or the like. sputtering targets and optical functional films. [Technical means to solve problems]

In order to solve the above-mentioned problems, the present invention relates to a sputtering target material according to an aspect of the present invention, which includes a first component composed of one or two carbides selected from W and Ta, and a first component composed of Si, In, Y, A second component composed of one or two or more oxides selected from Nb, V, Zn, Zr, Al, B, Mo, and W, in which the total content of W and Ta in the first component is 10 atomic % or more 35 atomic % or less.

The sputtering target thus constituted has the first component and the second component as described above, and the total content of W and Ta in the first component is within the range of 10 atomic % or more and 35 atomic % or less. An optical functional film which is excellent in heat resistance and can be etched favorably through an etchant containing hydrogen peroxide is formed. In addition, an optical functional film capable of sufficiently suppressing reflection of light from a metal thin film or the like can be formed.

Here, in the sputtering target according to one aspect of the present invention, it is preferable to have a structure in which the granular carbides are dispersed in the base phase of the oxides, and the carbides have an average particle size of Within the range of 1 μm or more and 150 μm or less. In this case, since the average particle size of the carbides is set to 1 μm or more, the density of the sputtering target can be increased. In addition, since the average particle size of the carbides is 150 μm or less, it becomes possible to stably form an optically functional film in which carbides and oxides are uniformly mixed by sputtering.

Further, in the sputtering target according to one aspect of the present invention, the upper density ratio is preferably 90% or more. In this case, since the density ratio is set to 90% or more, generation of particles due to abnormal discharge during sputtering can be suppressed, and film formation can be performed stably.

In addition, in the sputtering target according to one aspect of the present invention, it is preferable that the resistivity is 0.1 Ω·cm or less. In this case, since the resistivity is set to 0.1 Ω·cm or less, stable film formation can be performed without abnormal discharge by DC sputtering, and the optical functional film can be efficiently formed.

According to an aspect of the present invention, the optical functional film contains a first component composed of one or two carbides selected from W and Ta, and a first component composed of Si, In, Y, Nb, V, Zn, The second component is composed of one or two or more oxides selected from Zr, Al, B, Mo, and W, and the total content of W and Ta in the first component is in the range of 3 atomic % or more and 11 atomic % or less. Inside.

The optically functional film thus constituted has the first component and the second component as described above, and the total content of W and Ta in the first component is within the range of 3 atomic % or more and 11 atomic % or less, so the heat resistance is improved. It is excellent in the aspect and can be satisfactorily etched through an etching solution containing hydrogen peroxide. Furthermore, it becomes possible to sufficiently suppress reflection of light from a metal thin film or the like.

Here, the optical functional film according to one aspect of the present invention preferably has a visible light reflectance of 20% or less when the surface in contact with the Cu film is formed in a thickness of 25 nm or more and 75 nm or less. In this case, since the above-mentioned visible light reflectance is suppressed to be as low as 20% or less, it becomes possible to surely suppress the reflection of light from the laminated metal thin film or the like.

Moreover, in the optical functional film concerning one aspect of this invention, it is preferable that the surface resistance in the upper thickness 50nm is 10< ⁶ > ohm/sq. or less. In this case, the surface resistance at a thickness of 50 nm is 10 ⁶ Ω/sq. or less, the electrical conductivity is ensured, and electricity can be supplied through the optical functional film.

Furthermore, in the optical functional film which concerns on one aspect of this invention, it is preferable that the etching rate based on a hydrogen peroxide etchant exists in the range of 0.3 mm/sec. or more and 5.8 mm/sec. or less. In this case, since the etching rate by the hydrogen peroxide etching solution is set within the range of 0.3 mm/sec. or more and 5.8 mm/sec. or less, it becomes possible to laminate the optical functional film according to one aspect of the present invention When on the metal thin film, the etching process is performed well together with the metal thin film, and patterning is performed efficiently.

Further, in the optical functional film according to one aspect of the present invention, it is preferable that the product of the film thickness d, the refractive index n in the visible light region, and the extinction coefficient k in the visible light region, n×k×d be within a range of 40 or more and 100 or less. . In this case, the absorption and interference of visible light can be transmitted, and the reflection of visible light can be suppressed more reliably.

Furthermore, in the optical functional film according to one aspect of the present invention, it is preferable to form a film on the surface in contact with the Cu film in a thickness of 25 nm or more and 75 nm or less, and to maintain visible light after heat treatment at 400° C. for 10 minutes. The reflectivity is 20% or less. In this case, since the visible light reflectance after heat treatment held at 400° C. for 10 minutes is 20% or less, even if heat treatment is performed, the optical properties do not change significantly, and it is excellent in heat resistance. [Compared to the efficacy of the prior art]

According to one aspect of the present invention, it is possible to provide a sputtering target for forming an optical functional film which is excellent in etching resistance and heat resistance by an etching solution containing hydrogen peroxide, and which can sufficiently suppress reflection of light from a metal thin film or the like. and optical functional films.

Hereinafter, the sputtering target and the optical functional film which are embodiments of the present invention will be described with reference to the drawings.

The optical functional film 12 according to the present embodiment is formed so as to be laminated on the metal wiring film 11 formed on the surface of the substrate 1 as shown in FIG. 1 . Here, the metal wiring film 11 is formed of aluminum, an aluminum alloy, copper, or a copper alloy, which is a metal excellent in electrical conductivity, and is formed of copper in this embodiment. This metal wiring film 11 has metallic luster, so it reflects visible light and is visually recognized from the outside.

The optical functional film 12 of the present embodiment is provided to suppress reflection of visible light in the laminated metal wiring film 11 . The optical functional film 12 of the present embodiment contains a first component composed of one or two carbides selected from W and Ta, and a first component composed of Si, In, Y, Nb, V, Zn, Zr, Al, and B. The second component is composed of one or two or more oxides selected from Mo and W, so that the total content of W and Ta in the first component is within the range of 3 atomic % or more and 11 atomic % or less.

The first component composed of one or two carbides selected from W and Ta has electrical conductivity, and the electrical conductivity of the optical functional film 12 is ensured through the first component. Moreover, the heat resistance of the optical functional film 12 is improved by this 1st component. In terms of the second component composed of one or two or more oxides selected from Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo, and W, by mixing with the above-mentioned first component, The optical properties of the optical functional film 12 can be adjusted. In addition, by adopting the above-mentioned composition, the etching process can be favorably performed through an etching solution containing hydrogen peroxide.

When the total content of W and Ta in the first component is less than 3 atomic %, the heat resistance and conductivity of the optical functional film 12 may be insufficient. When the total content of W and Ta in the first component exceeds 11 atomic %, the content of oxides such as Si is insufficient, and there is a possibility that the reflection of light from the metal thin film 11 and the like cannot be sufficiently suppressed. The lower limit of the total content of W and Ta in the first component in the optical functional film 12 of the present embodiment is more preferably 5.0 atomic % or more, and more preferably 7.0 atomic % or more. The upper limit of the total content of W and Ta in the first component is more preferably 10.0 atomic % or less, and more preferably 9.0 atomic % or less. The total content of Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo, and W in the second component is preferably in the range of 15 atomic % or more and 50 atomic % or less. The total content of W and Ta in the first component and the total content of Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo, and W in the second component are such that O and C are included. The total amount of all the elements is 100 atomic %. The remainder other than the elements whose contents are specified above are C, O, and unavoidable impurities.

Here, in the optical functional film 12 of the present embodiment, the visible light reflectance when the surface in contact with the Cu film is formed with a thickness of 25 nm or more and 75 nm or less is preferably higher than the reflectance of the Cu film (approximately 74%) small. Furthermore, 30% or less is preferable, and 20% or less is more preferable. For example, the optical functional film 12 is formed on the Cu film in a thickness ranging from 25 nm to 75 nm. When the visible light reflectance is 20% or less when the surface in contact with the Cu film is formed with a thickness ranging from 25 nm to 75 nm, it becomes possible to reliably suppress the visible light from the metal wiring film 11. reflection. In addition, in order to more reliably suppress the reflection of visible light on the metal wiring film 11, the visible light reflectance when the surface in contact with the Cu film is formed with a thickness of 25 nm or more and 75 nm or less is preferably 15%. Below, it is more preferable that it is 10% or less.

In addition, in the optical functional film 12 of the present embodiment, it is preferable that the surface resistance at a thickness of 50 nm is 10 ⁶ Ω/sq. or less. Thereby, it becomes possible to conduct conduction between the metal wiring film 11 and the external wiring via the optical functional film 12 . In addition, when the sheet resistance at a thickness of 50 nm exceeds 10 ⁶ Ω/sq., in order to conduct the metal wiring to the outside, holes are formed in the low-reflectance film and the substrate so that the conduction to the external wiring can be achieved. In addition, the surface resistance at a thickness of 50 nm is more preferably 10 ⁵ Ω/sq. or less, and more preferably 10 ⁴ Ω/sq. or less. The lower limit of the surface resistance in a thickness of 50 nm is preferably 10 Ω/sq. or more.

Furthermore, in the optical functional film 12 of the present embodiment, the etching rate based on the hydrogen peroxide etching solution is equal to or less than the etching rate (5.8 mm·sec.) of the Cu film, and preferably no undissolved portion is generated. 0.3mm/sec. or more and 5.8mm/sec. or less. According to this, etching is performed in a state where the metal wiring film 11 is laminated, and the wiring pattern can be formed favorably. Here, as the hydrogen peroxide etching solution, the hydrogen peroxide-based etching solution GHP-3 manufactured by Kanto Chemical Co., Ltd. can be used. In addition, the lower limit of the etching rate based on the hydrogen peroxide etching solution is more preferably 0.4 mm/sec. or more, and more preferably 0.5 mm/sec. or more. On the other hand, the upper limit of the etching rate based on the hydrogen peroxide etching solution is more preferably 3.0 mm/sec. or less, and more preferably 2.0 mm/sec. or less.

In addition, in the optical functional film 12 of the present embodiment, it is preferable that the product n×k×d of the film thickness d, the refractive index n in the visible light region, and the extinction coefficient k in the visible light region is in the range of 40 or more and 100 or less. In this optical functional film 12, the reflection of the metal wiring film 11 is suppressed by the absorption (extinction coefficient k) and interference (film thickness d and refractive index n) of visible light. The extinction coefficient k is adjusted to suppress reflection of visible light at all wavelengths, and the film thickness d and the refractive index n are adjusted to suppress the waveform and peak of the reflected light. In addition, the visible light region is a region with a wavelength of 380 to 780 nm.

In addition, when the product n×k×d of the film thickness d, the refractive index n in the visible light region, and the extinction coefficient k in the visible light region is within the above-mentioned range, the absorption and interference of the transmitted visible light can more reliably suppress the reflection in the visible light region. Further, the lower limit of d×n×k is preferably 50 or more, and more preferably 60 or more. On the other hand, the upper limit of d×n×k is more preferably 90 or less, and more preferably 80 or less.

Here, in the optical functional film 12 of the present embodiment, it is preferable to form a film with a thickness ranging from 25 nm to 75 nm on the surface in contact with the Cu film, and to reflect visible light after heat treatment held at 400° C. for 10 minutes. The rate is below 20%. According to this, the optical properties are not degraded even after the heat treatment, and the heat resistance is surely excellent. In addition, the surface in contact with the Cu film is formed with a thickness of 25 nm or more and 75 nm or less, and the visible light reflectance after heat treatment held at 400° C. for 10 minutes is preferably 15% or less, more preferably 10% or less. . In addition, the optical functional film 12 is formed on the Cu film in a thickness ranging from 25 nm to 75 nm.

Next, the sputtering target of the present embodiment will be described. The sputtering target of the present embodiment is for forming the above-described optical functional film 12 .

The sputtering target of this embodiment contains a first component composed of one or two carbides selected from W and Ta, and a first component composed of Si, In, Y, Nb, V, Zn, Zr, Al, B. The second component is composed of one or two or more oxides selected from Mo and W, and the total content of W and Ta in the first component is within the range of 10 atomic % or more and 35 atomic % or less.

The first component composed of one or two carbides selected from W and Ta has electrical conductivity, and the electrical conductivity of the sputtering target of the present embodiment is ensured by the first component. The second component composed of one or two or more oxides selected from Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo, and W is superior to the first component in terms of sinterability, and therefore The density ratio of the sputtering target of this embodiment is improved. Furthermore, by adopting the above-mentioned composition, the optical functional film 12 which can be satisfactorily etched through an etching solution containing hydrogen peroxide can be formed.

By making the total content of W and Ta in the first component of the sputtering target in the range of 10 atomic % or more and 35 atomic % or less, it is possible to make the total content of W and Ta in the first component 3 atomic % or more. The optical functional film of this embodiment in the range of 11 atomic% or less. The lower limit of the total content of W and Ta in the first component in the sputtering target of the present embodiment is preferably 12.0 atomic % or more, and more preferably 14.0 atomic % or more. The upper limit of the total content of W and Ta in the first component is more preferably 32.0 atomic % or less, and more preferably 29.0 atomic % or less. The total content of Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo, and W in the second component is preferably in the range of 7 atomic % or more and 41 atomic % or less. The total content of W and Ta in the first component and the total content of Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo, and W in the second component are such that O and C are included. The total amount of all the elements is 100 atomic %. The remainder other than the elements whose contents are specified above are C, O, and unavoidable impurities.

Here, in the sputtering target according to the present embodiment, it is preferable to set the structure in which carbides are dispersed in the form of islands in the base phase of the oxide, and the average particle size of the carbides is 1 μm or more. within the range of 150 μm or less. Here, the average particle diameter of the carbides is the number average of the circle-equivalent diameters. When the average particle size of the carbides is 1 μm or more, it is possible to increase the density of the sputtering target. In addition, when the average particle diameter of the carbides is 150 μm or less, it becomes possible to stably form an optically functional film in which carbides and oxides are uniformly mixed by sputtering. In addition, the lower limit of the average particle diameter of the carbides is more preferably 2 μm or more, and more preferably 8 μm or more. The upper limit of the average particle diameter of the carbide is more preferably 120 μm or less, and more preferably 80 μm or less. In addition, the upper limit of the average particle diameter of carbides may be 30 μm or less or 15 μm or less.

In addition, in the sputtering target of the present embodiment, the density ratio is preferably 90% or more. By making the density ratio 90% or more, generation of particles during sputtering can be suppressed. In addition, in the sputtering target of the present embodiment, the density ratio is preferably 92% or more, and more preferably 93% or more. The upper limit of the density ratio is preferably 100% or less.

In addition, in the sputtering target of the present embodiment, the resistivity is preferably 0.1 Ω·cm or less. The resistivity is set to 0.1 Ω·cm or less so that the optical functional film 12 can be stably formed by DC sputtering. In addition, in the sputtering target of the present embodiment, the resistivity is preferably 5×10 ^-2 Ω·cm or less, and more preferably 1×10 ^-2 Ω·cm or less. The lower limit of the resistivity is preferably 1×10 ^-6 Ω·cm or more.

Next, the manufacturing method of the sputtering target according to the present embodiment will be described with reference to FIG. 2 .

(Powder Mixing Program S01) In this embodiment, as shown in FIG. 2 , first component powder composed of one or two carbides selected from W and Ta is mixed with Si, In, Y, Nb, V, Zn, Zr, The second component powder composed of one or two or more oxides selected from Al, B, Mo, and W is weighed and mixed to obtain a sintered raw material powder. Here, the mixing method is not particularly limited, and a ball mill is used in this embodiment. In addition, the average particle diameter of the first component powder composed of carbides of one or two selected from W and Ta is preferably in the range of 1 μm or more and 150 μm or less. The average particle size of the second component powder composed of one or two or more oxides selected from Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo, and W is preferably 0.05 μm or more within the range of 0.3 μm or less. The average particle diameter of the first component powder and the second component powder described above is the D50 diameter on a volume basis.

(Sintering program S02) Next, the above-mentioned sintering raw material powder is heated and sintered while being pressurized to obtain a sintered body. In the present embodiment, sintering is carried out using a hot pressing apparatus or a hot isostatic pressing apparatus (HIP). In this sintering program S02, the sintering temperature is in the range of 650°C or more and 1000°C or less, the holding time at the sintering temperature is in the range of 0.5 hours or more and 15 hours or less, and the pressing pressure is in the range of 10MPa or more and 200MPa or less. .

(Machining program S03) Next, the obtained sintered body is machined into a predetermined size. Thereby, the sputtering target of this embodiment is manufactured.

In the case of the sputtering target of the present embodiment having the above configuration, the first component is composed of one or two carbides selected from W and Ta, and the first component is composed of Si, In, Y, and Nb. , V, Zn, Zr, Al, B, Mo, W selected one or two or more oxides of the second component, and the total content of W and Ta in the first component is 10 atomic % or more 35 In the range of atomic % or less, the optical functional film 12 which is excellent in heat resistance and can be etched well through an etchant containing hydrogen peroxide can be formed. Moreover, the optical function film 12 which can fully suppress reflection of light from a metal thin film etc. can be formed.

In the sputtering target of the present embodiment, when a structure in which granular carbides are dispersed in an oxide base phase is formed, and the average particle size of the carbides is in the range of 1 μm or more and 150 μm or less, It becomes possible to stably form the optical functional film 12 in which carbide and oxide are uniformly mixed by sputtering while achieving high density of the sputtering target.

In addition, in the sputtering target of the present embodiment, when the density ratio is 90% or more, generation of particles during sputtering can be suppressed, and the optical functional film 12 can be formed by stable sputtering. Furthermore, in the sputtering target of the present embodiment, when the resistivity is 0.1 Ω·cm or less, film formation can be performed stably by DC sputtering, and the optical functional film 12 can be efficiently formed.

In the case of the optical functional film 12 according to the present embodiment, since the first component is composed of one or two carbides selected from W and Ta, and the first component is composed of Si, In, Y, Nb, V, and Zn. A second component composed of one or more oxides selected from Zr, Al, B, Mo, and W, and the total content of W and Ta in the first component is 3 atomic % or more and 11 atomic % or less Within the range, it is excellent in heat resistance and can be satisfactorily etched through an etchant containing hydrogen peroxide. Furthermore, it becomes possible to sufficiently suppress reflection of light from a metal thin film or the like.

In the optical functional film 12 of the present embodiment, when the visible light reflectance is 20% or less when the surface in contact with the Cu film is formed with a thickness of 25 nm or more and 75 nm or less, the reflectance of visible light is 20% or less. Reflection of light from the metal wiring film 11 is suppressed in the ground. Further, in the optical functional film 12 of the present embodiment, when the surface resistance at a thickness of 50 nm is 10 ⁶ Ω/sq. or less, electrical conductivity is ensured and electricity can be supplied through the optical functional film 12 .

In addition, in the optical functional film 12 of the present embodiment, when the etching rate by the hydrogen peroxide etching solution is in the range of 0.3 mm/sec. or more and 5.8 mm/sec. or less, it is laminated on the metal wiring film Above 11, the etching process can be performed well together with the metal wiring film 11, and patterning can be performed efficiently.

In addition, in the optical functional film 12 of the present embodiment, when the product n×k×d of the film thickness d, the refractive index n in the visible light region, and the extinction coefficient k in the visible light region is in the range of 40 or more and 100 or less, It becomes possible to more reliably suppress the reflection of visible light through absorption and interference of visible light. In addition, in the optical functional film 12 of the present embodiment, the visible light reflectance after the heat treatment of the surface in contact with the Cu film in a thickness of 25 nm or more and 75 nm or less and holding at 400° C. for 10 minutes is In the case of 20% or less, even if heat treatment is performed, the optical properties do not change significantly, and the heat resistance is excellent.

In addition, the optical functional film 12 of the present embodiment is an optical functional film 12 formed on the metal wiring film 11 containing Al or Cu or between the substrate and the metal wiring film 11, and contains an optical function film 12 selected from W and Ta. The first component is composed of one or two kinds of carbides and one or more kinds of oxides selected from Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo, W and the visible light reflectance when the film is formed in a thickness of 25 nm or more and 75 nm or less is 20% or less.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can change as needed in the range which does not deviate from the technical requirements of this invention. For example, in this embodiment, the laminated film having the structure shown in FIG. 1 has been described as an example, but it is not limited to this, and the optical function of this embodiment may be formed between the substrate and the metal wiring. The film 12 is a laminated film of a glass substrate/optical function film/metal wiring structure. In this case, the light from the glass substrate is reflected. In addition, in this configuration, electrical conductivity is not required in terms of the optical functional film. [Example]

Hereinafter, the result of the evaluation test which evaluated the effect of the sputtering target material and the optical functional film concerning this embodiment is demonstrated.

As shown in Tables 1 and 2, the first component powder composed of one or two carbides selected from W and Ta and the powder composed of Si, In, Y, Nb, V, Zn, Zr, Al, A second component powder composed of one or two or more oxides selected from B, Mo, and W. 1kg of the weighed raw material powder and 1.3kg of balls with a ϕ5mm were put into a 3L pot. Next, the raw material powders are mixed with a ball mill to obtain raw material powders for sintering. All of the powders used those having a purity of 99.9% by mass or more.

In addition, the average particle diameters of the first component powder and the second component powder were measured in the following manner. 100 mL of an aqueous solution with a sodium hexametaphosphate concentration of 0.2 vol% was prepared, 10 mg of each raw material powder was added to the aqueous solution, and the particle size distribution (volumetric) was measured using a laser diffraction scattering method (measuring device: Microtrac MT3000, manufactured by NIKKISO Co., Ltd.). benchmark). From the obtained particle size distribution (volume basis), the average particle diameter of the first component powder and the average particle diameter (D50 diameter) of the second component powder were determined.

Using the above-mentioned raw material powder for sintering, sintering is performed by hot pressing or HIP to obtain a sintered body. For hot pressing, a carbon hot-pressed mold (ϕ135 mm) was filled with the raw material powder for sintering, and hot-pressed in vacuum at 830° C. and the pressure described in Tables 1 and 2 for 3 hours to produce a sintered body. For HIP, first, the mixed powder (raw material powder for sintering) was filled in a rubber mold of φ225mm, and press-molded at 150MPa for 5 minutes with a cold equalizing pressure (CIP) device to produce a molded body. After that, a formed body was placed in a tank of SPCC (rolled steel), and SPCC was welded. Next, vacuum was evacuated to 0.001 Pa or less, and then the can was sealed. Sintering was performed at 850° C. and the pressure described in Tables 1 and 2 for 2 hours to produce a sintered body.

These sintered bodies were machined into diameters of 125 mm and thicknesses of 5 mm, and were then adhered to a Cu backplane with In solder to produce sputtering targets. In addition, in order to reduce impurity elements, it is preferable to use a higher-purity raw material powder. In addition, indium oxide powder and zinc oxide powder may be reduced during hot pressing and HIP to precipitate In and Zn. For this reason, it is preferable that boron nitride is sufficiently applied to the carbon mold so that the carbon mold does not come into direct contact with the indium oxide powder and the zinc oxide powder.

The sputtering target obtained as described above and the optical functional film formed using the sputtering target were evaluated for the following items.

(Composition of sputtering target) Quantitative analysis of each metal component and C and O components was carried out by quantitative analysis with an EPMA apparatus, and a quantitative result was obtained, and it was confirmed that there was no significant change in the composition when the raw materials were mixed. For both the carbides and the oxides of W, the ratio of the carbides of W to the oxides of W is obtained by performing XPS analysis, and the W in the first component is obtained respectively using the obtained ratio and the quantitative result. and the amount of W in the second component.

(Density ratio of sputtering target) The volume of the sputtering target was calculated from the size of the obtained processed sputtering target, and the dimensional density of the sputtering target was calculated by dividing the measured weight value by the volume. The ratio of dividing the dimensional density by the calculated density is described in Tables 3 and 4 as "density ratio". In addition, the calculated density was calculated according to the following formula. Calculated density (g/cm ³ )=100/{the first component cutting amount (mass%)/the first component theoretical density (g/cm ³ ) + the second component cutting amount (mass%)/the second component theory Density (g/cm ³ )}

(structure of sputtering target) An observation sample was extracted from the obtained sputtering target, embedded in epoxy resin, and polished. Next, elemental mapping was performed on a range of 36 μm×28 μm at a magnification of 3000 times using an electron probe microanalyzer (EPMA) apparatus. The microstructure of the first component and the second component was observed from the map image of the metal contained in the first component and the map image of the metal contained in the second component. In addition, the average particle size of the carbides (average of the number of equivalent circle diameters) was calculated and described in Tables 3 and 4. Here, the observation result of Example 1 of the present invention is shown in FIG. 3 , and the observation result of Example 2 of the present invention is shown in FIG. 4 .

(specific resistance of sputtering target) About the center part of the sputtering surface of the obtained sputtering target, using the low resistance meter (Loresta-GP) by Mitsubishi Chemical Co., Ltd., the value measured by the four-point probe method is described in the table|surface. The measurement was performed at a temperature of 23±5°C (18°C to 28°C) and a humidity of 50±20% (30% to 70%) at the time of measurement. In addition, an ASP probe was used as a probe during measurement.

(Measurement of the number of abnormal discharges) Ar was discharged at 50 sccm in the sputtering chamber, and the total pressure in the chamber was 0.67 Pa, and the TS distance was 70 mm at DC, and the sputtering was performed at 5.0 W/cm ² for 1 hour. . The number of abnormal discharges at the time of this sputtering was recorded. The power supply used the DC power supply device RPG-50 made by mks company.

(Evaluation of single film) For the obtained sputtering target, Ar was evacuated at 50 sccm in the sputtering chamber, under the condition that the total pressure in the chamber was 0.67 Pa, DC, the TS distance was 70 mm, and the output described in Tables 5 and 6 was in the side length. A film with a thickness of 50 nm was formed on a 20 mm square Si substrate. The film was formed under the above-mentioned conditions in advance, and the adhesion rate of the film was calculated. Then, the film-forming time to obtain the target film thickness (50 nm) was obtained. Regarding the film thickness, the film was formed and managed during the film formation time of the target film thickness (50 nm) calculated when the film was formed in advance. About the obtained film, the following evaluation (1)-(4) was implemented.

(1) Analysis of film composition Quantitative results were obtained by quantitative analysis of each metal component and C and O components by quantitative analysis of the EPMA apparatus. For both the carbides and the oxides of W, the ratio of the carbides of W to the oxides of W is obtained by performing XPS analysis, and the W in the first component is obtained respectively using the obtained ratio and the quantitative result. and the amount of W in the second component. From the obtained results, the ratio of each component was calculated when the total value of the detected metal component and the C and O components was 100 atomic %. In addition, in Comparative Example 4, each metal component and C, O, and N components were quantified, and the ratio of each component was calculated when the total value of the metal component, C, O, and N components was 100 atomic %.

(2) Determination of refractive index and extinction coefficient The refractive index and extinction coefficient of the visible light region (380-780 nm wavelength band) were measured and calculated for the film-forming sample with a film thickness of 50 nm using UVISEL-HR320 (Horiba ellipsometry).

(3) Measurement of specific resistance The values measured by the four-probe method using Loresta-GP (manufactured by Mitsubishi Chemical Analytech) are shown in Tables 7 and 8. The measurement was performed at a temperature of 23±5°C (18°C to 28°C) and a humidity of 50±20% (30% to 70%) at the time of measurement. In addition, a PSP detector was used as the detector during the measurement.

(4) Measurement of etching rate A film-forming sample with a film thickness of 50 nm was immersed in a commercially available hydrogen peroxide-based etching solution GHP-3 (manufactured by Kanto Chemical Co., Ltd.), and the time until the film melted was measured. The etching rate was obtained by dividing the value of this time by the value of the film thickness. During the measurement, the temperature of the etching solution was set to 40±5°C (35°C to 45°C).

(Measurement of reflectance) A Cu film with a thickness of 200 nm was formed on a glass substrate. Then, in the sputtering chamber, Ar was evacuated at 50 sccm in the sputtering chamber, and the total pressure in the chamber was 0.67 Pa so that each of the above-mentioned optical functional films had an appropriate film thickness d (25 nm or more and 75 nm or less) on the surface in contact with the Cu film. In the state, the TS distance was set to 70 mm in DC, and film formation was performed with the outputs described in Tables 5 and 6, and a laminated film was produced. Next, the reflectance of the laminated film formed on the glass substrate as described above was measured. Here, the measurement was performed using a spectrophotometer (U-4100, manufactured by Hitachi, Ltd.) at a wavelength of 380 to 780 nm from the side of the film on which the film was formed.

(Heat resistance test) The produced laminated film was heat-processed at 400 degreeC and nitrogen atmosphere for 10 minutes by the measurement of reflectance. The reflectance after heat treatment was similarly measured immediately after film formation.

In Comparative Example 1, although the sputtering target contained WC as the first component and ZnO and Y ₂ O ₃ as the second component, the content of W was 8.0 atomic %, and the amount of W in the optically functional film formed was The content was 2.8 atomic %. In this optical functional film, the reflectance greatly increased after the heat treatment at 400°C, and the heat resistance was insufficient.

In Comparative Example 2, although the sputtering target contained WC as the first component and Y ₂ O ₃ as the second component, the content of W was set to 39.0 atomic %, and the content of W in the optically functional film formed was 13.6 atomic %. In this optical functional film, the reflectance before heat treatment is relatively large at 35%, and the reflection of visible light by the metal thin film cannot be sufficiently suppressed.

In Comparative Example 3, the sputtering target was made of metal Cu, and oxygen was introduced during sputtering to form an optical functional film made of copper oxide (CuO). In this optical functional film, the reflectance greatly increased after the heat treatment at 400°C, and the heat resistance was insufficient.

In Comparative Example 4, the sputtering target was made of metal Cu, and nitrogen and oxygen were introduced during sputtering to form an optical functional film made of copper oxynitride (CuNO). In this optical functional film, the surface resistance becomes very high. In addition, it is insoluble in hydrogen peroxide etching solution and cannot be etched.

On the other hand, in Examples 1 to 33 of the present invention, the sputtering target contains the first component and the second component, and the total content of W and Ta in the first component is within the range of 10 atomic % or more and 35 atomic % or less, The total content of W and Ta in the first component in the formed optical functional film is set to be in the range of 3 atomic % or more and 11 atomic % or less. These optical functional films have low reflectance of visible light before heat treatment, and can sufficiently suppress the reflection of visible light by the metal thin film. In addition, after the heat treatment, the reflectance of visible light did not change significantly, and it was excellent in heat resistance. In addition, the etching process can be performed favorably through a hydrogen peroxide etchant.

From the above, it has been confirmed that according to the present invention, it is possible to provide sputtering of an optical functional film which is excellent in etching property and heat resistance by an etching solution containing hydrogen peroxide and which can sufficiently suppress reflection of light from a metal thin film or the like. Coating target and optical functional film. [industrial availability]

The sputtering target of the present embodiment is suitable for a low-reflectivity film provided in a sensing electrode (metal film) provided in a projection-type capacitive touch panel, and a process for forming a black matrix in a flat panel display.

12: Optical functional film

[ Fig. 1] Fig. 1 is an explanatory cross-sectional view of a laminated film provided with an optical functional film according to an embodiment of the present invention. [ Fig. 2] Fig. 2 is a flowchart showing a method for producing a sputtering target according to an embodiment of the present invention. 3] Observation results of the structure of the sputtering target of Example 1 of the present invention. 4] Observation results of the structure of the sputtering target of Example 2 of the present invention.

Claims (10)

A sputtering target containing a first component composed of one or two carbides selected from W and Ta, and a first component composed of Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo , the second component composed of one or two or more oxides selected by W, The total content of W and Ta in the first component is set within a range of 10 atomic % or more and 35 atomic % or less. The sputtering target according to claim 1, wherein the granular carbide is dispersed in the oxide base phase, and the carbide has an average particle size in the range of 1 μm or more and 150 μm or less. The sputtering target according to claim 1 or 2, wherein the density ratio is 90% or more. The sputtering target according to any one of claims 1 to 3, wherein the resistivity is set to 0.1 Ω·cm or less. An optical functional film comprising a first component composed of one or two carbides selected from W and Ta, and a first component composed of Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo, The second component consisting of one or two or more oxides selected from W, The total content of W and Ta in the first component is set within a range of 3 atomic % or more and 11 atomic % or less. The optical functional film according to claim 5, which has a visible light reflectance of 20% or less when the surface in contact with the Cu film is formed with a thickness ranging from 25 nm to 75 nm. The optical functional film according to claim 5 or 6, wherein the surface resistance at a thickness of 50 nm is 10 ⁶ Ω/sq. or less. The optical functional film according to any one of claims 5 to 7, wherein the etching rate based on the hydrogen peroxide etching solution is within a range of 0.3 mm/sec. or more and 5.8 mm/sec. or less. The optical functional film according to any one of claims 5 to 8, wherein the product n×k×d of the film thickness d, the refractive index n in the visible light region, and the extinction coefficient k in the visible light region is within a range of 40 or more and 100 or less . The optical functional film according to any one of claims 5 to 9, wherein the surface in contact with the Cu film is formed into a film with a thickness ranging from 25 nm to 75 nm, and the visible light reflection after heat treatment held at 400° C. for 10 minutes The rate is below 20%.

Images