WO2021241687A1

WO2021241687A1 - Sputtering target and optical functional film

Info

Publication number: WO2021241687A1
Application number: PCT/JP2021/020200
Authority: WO
Inventors: 大亮金子; 啓太梅本; 幸也杉内; 晋岡野; 健志大友
Original assignee: 三菱マテリアル株式会社
Priority date: 2020-05-28
Filing date: 2021-05-27
Publication date: 2021-12-02
Also published as: TW202200816A

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 target and optical functional film

The present invention relates to a sputtering target used for forming an optical functional film that is laminated on a metal thin film or the like to reduce reflection of light from the metal thin film or the like, and an optical functional film.
This application claims priority under Japanese Patent Application No. 2020-093236 filed in Japan on May 28, 2020 and Japanese Patent Application No. 2021-08638 filed in Japan on May 24, 2021. , The contents are used here.

In recent years, a projection type capacitive touch panel has been adopted as an input means for a mobile terminal device or the like. In this type of touch panel, a sensing electrode is formed for touch position detection. The electrode for sensing is 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 formed on one surface of the transparent substrate. These are provided and arranged in a grid pattern.
Here, when a metal thin film is used for the electrodes of the touch panel, the pattern of the electrodes is visually recognized from the outside because the metal thin film has a metallic luster. Therefore, it is conceivable to reduce the visibility of the electrode by forming a low-reflectance film having a low reflectance of visible light on the metal thin film.

Further, in a flat panel display represented by a liquid crystal display device or a plasma display, a color filter for color display is adopted. In this color filter, a black member called a black matrix is formed for the purpose of improving contrast and color purity and improving visibility.
The above-mentioned low reflectance film can also be used as this black matrix (hereinafter referred to as “BM”).

Further, in the solar cell panel, when sunlight is incident through a glass substrate or the like, a back electrode of the solar cell is formed on the opposite side thereof. As the back surface electrode, a metal thin film such as molybdenum (Mo) or silver (Ag) is used. When the solar cell panel of such an aspect is viewed from the back surface side, the metal thin film which is the back surface electrode is visually recognized.
Therefore, it is conceivable to reduce the visibility of the back surface electrode by forming the above-mentioned low reflectance film on the back surface electrode.

Here, in the laminated film of the wiring film and the low reflectance film described above, patterning is performed by etching, for example, as described in Patent Documents 1 and 2.
In Patent Document 1, patterning is performed using an etching solution containing hydrogen peroxide.

By the way, in the above-mentioned laminated film of the wiring film and the low reflectance film, heat treatment of, for example, about 400 ° C. may be applied in the subsequent steps. Therefore, heat resistance is required so that the optical performance does not deteriorate even by the heat treatment at about 400 ° C.
Further, as described above, since the laminated film of the wiring film and the low reflectance film is patterned by etching, it is required to have excellent etching property.

Here, in the low reflectance film described in Patent Document 1, the etching property by the etching solution containing hydrogen peroxide is excellent, but the heat resistance is insufficient.
Further, the low reflectance film described in Patent Document 2 is a copper oxynitride film (CuNO film) and has excellent heat resistance, but the etching property by an etching solution containing hydrogen peroxide is insufficient. Met.

Japanese Unexamined Patent Publication No. 2015-130007 Japanese Unexamined Patent Publication No. 2016-186928

The present invention has been made in view of the above-mentioned circumstances, and is excellent in etching property and heat resistance by an etching solution containing hydrogen peroxide, and can sufficiently suppress reflection of light from a metal thin film or the like. It is an object of the present invention to provide a sputtering target for forming an optical functional film and an optical functional film.

In order to solve the above problems, the sputtering target according to one aspect of the present invention is a first component composed of one or two kinds of carbides selected from W and Ta, and Si, In, Y, Nb, V and Zn. , Zr, Al, B, Mo, W contains a second component composed of one or more oxides selected from, and the total content of W, Ta in the first component is 10 atomic%. It is characterized in that it is within the range of 35 atomic% or less.

According to the sputtering target having this configuration, as described above, it has a first component and a 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. Therefore, it is possible to form an optical functional film having excellent heat resistance and being able to be satisfactorily etched with an etching solution containing hydrogen peroxide. Further, it is possible to form an optical functional film capable of sufficiently suppressing the reflection of light from a metal thin film or the like.

Here, in the sputtering target according to one aspect of the present invention, the structure is such that the granular carbides are dispersed in the matrix of the oxide, and the average particle size of the carbides is within the range of 1 μm or more and 150 μm or less. It is preferable that
In this case, since the average particle size of the carbide is 1 μm or more, the density of the sputtering target can be increased. Further, since the average particle size of the carbide is 150 μm or less, it is possible to stably form an optical functional film in which the carbide and the oxide are uniformly mixed by sputtering.

Further, in the sputtering target according to one aspect of the present invention, the density ratio is preferably 90% or more.
In this case, since the density ratio is 90% or more, it is possible to suppress the generation of particles due to abnormal discharge during sputtering, and stable film formation can be achieved.

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

The optical functional film according to one aspect of the present invention comprises a first component composed of one or two carbides selected from W and Ta, and Si, In, Y, Nb, V, Zn, Zr, Al, B, It contains a second component composed of one or more oxides selected from 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. It is characterized by being inside.

According to the optical functional film having this configuration, as described above, it has a first component and a second component, 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. Since it is inside, it has excellent heat resistance and can be satisfactorily etched with an etching solution containing hydrogen peroxide. In addition, it is possible to sufficiently suppress the reflection of light from a metal thin film or the like.

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

In the optical functional film according to one embodiment of the present invention, the sheet resistance of a thickness 50nm is 10 ⁶ Ω / sq. The following is preferable.
In this case, the sheet resistance of a thickness 50nm is 10 ⁶ Ω / sq. Conductivity is ensured as follows, and energization can be performed through this optical functional film.

Further, in the optical functional film according to one aspect of the present invention, the etching rate with the hydrogen peroxide etching solution is 0.3 mm / sec. Above 5.8 mm / sec. It is preferably within the following range.
In this case, the etching rate with the hydrogen peroxide etching solution is 0.3 mm / sec. Above 5.8 mm / sec. Since it is within the following range, when the optical functional film according to one aspect of the present invention is laminated on the metal thin film, it can be satisfactorily etched together with the metal thin film, and patterning can be performed efficiently. It will be possible.

Further, in the optical functional film according to one aspect of the present invention, 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 range of 40 or more and 100 or less. It is preferable that
In this case, the absorption and interference of visible light makes it possible to more reliably suppress the reflection of visible light.

Further, in the optical functional film according to one aspect of the present invention, a film is formed on the surface in contact with the Cu film within a thickness range 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 high. It is preferably 20% or less.
In this case, since the visible light reflectance after the heat treatment held at 400 ° C. for 10 minutes is 20% or less, the optical characteristics do not change significantly even if the heat treatment is performed, and the heat resistance is excellent.

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

It is sectional drawing explanatory drawing of the laminated film provided with the optical functional film which concerns on one Embodiment of this invention. It is a flow figure which shows the manufacturing method of the sputtering target which concerns on one Embodiment of this invention. It is an observation result of the structure of the sputtering target of the present invention example 1. It is the observation result of the structure of the sputtering target of the present invention example 2.

Hereinafter, the sputtering target and the optical functional film according to the embodiment of the present invention will be described with reference to the attached drawings.

As shown in FIG. 1, 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.
Here, the metal wiring film 11 is made of aluminum, an aluminum alloy, copper, a copper alloy, or the like, which are metals having excellent conductivity, and in this embodiment, it is made of copper. Since the metal wiring film 11 has a metallic luster, it reflects visible light and is visually recognized from the outside.

The optical functional film 12 of the present embodiment is provided to suppress the reflection of visible light in the laminated metal wiring film 11.
The optical functional film 12 of the present embodiment has a first component composed of one or two kinds of carbides selected from W and Ta, and Si, In, Y, Nb, V, Zn, Zr, Al, B and Mo. , A second component consisting of one or more oxides selected from W, 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. Has been done.

The first component composed of one or two kinds of carbides selected from W and Ta has conductivity, and the conductivity of the optical functional film 12 is ensured by this first component. Further, the heat resistance of the optical functional film 12 is improved by this first component.
The second component consisting of one or more oxides selected from Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo and W is mixed with the above-mentioned first component. This makes it possible to adjust the optical characteristics of the optical functional film 12.
Further, by adopting the above-mentioned composition, it is possible to perform an etching treatment satisfactorily with an etching solution containing hydrogen peroxide.

If 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. If the total content of W and Ta in the first component exceeds 11 atomic%, the content of oxides such as Si may be insufficient, and the reflection of light from the metal thin film 11 or the like may not 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, still 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, still 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 O, The total amount of all elements including C is 100 atomic%.
The rest other than the above-mentioned elements whose contents are specified are C, O, and unavoidable impurities.

Here, in the optical functional film 12 of the present embodiment, the visible light reflectance when a film is formed on the surface in contact with the Cu film within a thickness range of 25 nm or more and 75 nm or less is the reflectance of the Cu film (about 74). %) Is preferably smaller. Further, it is preferably 30% or less, and further preferably 20% or less. For example, the optical functional film 12 is formed on the Cu film in a thickness range of 25 nm or more and 75 nm or less.
When the visible light reflectance is 20% or less when a film is formed on the surface in contact with the Cu film within a thickness range of 25 nm or more and 75 nm or less, the reflection of visible light on the metal wiring film 11 can be reliably suppressed. It will be possible.
Further, in order to surely suppress the reflection of visible light on the metal wiring film 11, the visible light reflectance is 15% or less when a film is formed on the surface in contact with the Cu film within a thickness range of 25 nm or more and 75 nm or less. It is more preferably present, and further preferably 10% or less.

Furthermore, the optical functional film 12 is this embodiment, the sheet resistance of a thickness 50nm is 10 ⁶ Ω / sq. It is preferably as follows. This makes it possible to conduct conduction between the metal wiring film 11 and the external wiring via the optical functional film 12. In addition, the sheet resistance of a thickness of 50nm is 10 ⁶ Ω / sq. If it exceeds, the metal wiring and the outside can be electrically connected to each other by forming a hole in the low reflectance film or the substrate.
The sheet resistance of the thick 50nm is 10 ⁵ Ω / sq. More preferably to less, 10 ⁴ Ω / sq. The following is more preferable.
The lower limit of the sheet resistance at a thickness of 50 nm is preferably 10 Ω / sq. That is all.

Further, in the optical functional film 12 of the present embodiment, the etching rate of the hydrogen peroxide etching solution is 0.3 mm or less of the etching rate of the Cu film (5.8 mm · sec.), And no undissolved residue is generated. / Sec. Above 5.8 mm / sec. It is preferably within the following range.
This makes it possible to form a wiring pattern satisfactorily by etching in a state of being laminated with the metal wiring film 11. Here, as the hydrogen peroxide etching solution, for example, a hydrogen peroxide-based etching solution GHP-3 manufactured by Kanto Chemical Co., Inc. can be used.
The lower limit of the etching rate with the hydrogen peroxide etching solution is 0.4 mm / sec. The above is more preferable, and 0.5 mm / sec. The above is more preferable. On the other hand, the upper limit of the etching rate with the hydrogen peroxide etching solution is 3.0 mm / sec. It is more preferably 2.0 mm / sec. The following is more preferable.

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

Then, by setting the product n × k × d of the film thickness d, the refraction coefficient n in the visible light region, and the extinction coefficient k in the visible light region within the above range, the visible light region is absorbed and interfered with by the visible light region. It is possible to suppress the reflection of light more reliably.
The lower limit of d × n × k is more preferably 50 or more, and further preferably 60 or more. On the other hand, the upper limit of d × n × k is more preferably 90 or less, and further preferably 80 or less.

Here, in the optical functional film 12 of the present embodiment, a film is formed on the surface in contact with the Cu film within a thickness range 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 high. It is preferably 20% or less. As a result, the optical characteristics do not deteriorate even after the heat treatment is performed, and the heat resistance is definitely excellent.
The visible light reflectance is more preferably 15% or less after heat treatment in which a film is formed on the surface in contact with the Cu film in a thickness of 25 nm or more and 75 nm or less and held at 400 ° C. for 10 minutes. Is more preferable. Further, for example, the optical functional film 12 is formed on the Cu film in a thickness range of 25 nm or more and 75 nm or less.

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

The sputtering target of this embodiment has a first component consisting of one or two carbides selected from W and Ta, and Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo and W. It contains a second component composed of one or more kinds of oxides selected from the 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. There is.

The first component composed of one or two kinds of carbides selected from W and Ta has conductivity, and the first component ensures the conductivity of the sputtering target of the present embodiment.
The second component, which consists of one or more oxides selected from Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo, and W, is more sinterable than the first component. Since it is excellent, the density ratio of the sputtering target according to the present embodiment is improved.
Further, by adopting the above-mentioned composition, it is possible to form an optical functional film 12 that can be satisfactorily etched with an etching solution containing hydrogen peroxide.

By setting the total content of W and Ta in the first component of the sputtering target within the range of 10 atomic% or more and 35 atomic% or less, the total content of W and Ta in the first component is 3 atomic% or more and 11 The optical functional film of the present embodiment within the range of atomic% or less can be formed.
The lower limit of the total content of W and Ta in the first component in the sputtering target of the present embodiment is more preferably 12.0 atomic% or more, still 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, still 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 O, The total amount of all elements including C is 100 atomic%.
The rest other than the above-mentioned elements whose contents are specified are C, O, and unavoidable impurities.

Here, in the sputtering target of the present embodiment, the structure is such that carbides are dispersed in an island shape in the matrix phase of the above-mentioned oxide, and the average particle size of the carbides is within the range of 1 μm or more and 150 μm or less. It is preferable that it is.
Here, the average particle size of the carbide is the average number of circle-equivalent diameters.
When the average particle size of the carbide is 1 μm or more, the density of the sputtering target can be increased. Further, when the average particle size of the carbide is 150 μm or less, it is possible to stably form an optical functional film in which the carbide and the oxide are uniformly mixed by sputtering.
The lower limit of the average particle size of the carbide is more preferably 2 μm or more, further preferably 8 μm or more. The upper limit of the average particle size of the carbide is more preferably 120 μm or less, and further preferably 80 μm or less. The upper limit of the average particle size of the carbide may be 30 μm or less, or 15 μm or less.

Further, in the sputtering target of the present embodiment, the density ratio is preferably 90% or more. By setting the density ratio to 90% or more, it is possible to suppress the generation of particles during sputtering.
In the sputtering target of the present embodiment, the density ratio is preferably 92% or more, more preferably 93% or more.
The upper limit of the density ratio is preferably 100% or less.

Further, in the sputtering target of the present embodiment, the resistivity is preferably 0.1 Ω · cm or less. By setting the resistivity to 0.1 Ω · cm or less, the optical functional film 12 can be stably formed by DC sputtering.
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 specific resistivity is preferably 1 × 10 ^-6 Ω · cm or more.

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

(Powder mixing step S01)
In the present embodiment, first, as shown in FIG. 2, a first component powder composed of one or two carbides selected from W and Ta, and Si, In, Y, Nb, V, Zn, Zr, A second component powder composed of one 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, but in the present embodiment, a ball mill device is used.
Further, the average particle size of the first component powder composed of one or two kinds of carbides 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 consisting of one or more oxides selected from Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo and W is 0.05 μm or more and 0. It is preferably within the range of .3 μm or less.
The average particle size of the first component powder and the second component powder described above is the volume-based D50 diameter.

(Sintering step S02)
Next, the above-mentioned sintered raw material powder is sintered by heating while pressurizing to obtain a sintered body. In this embodiment, sintering is performed using a hot press device or a hot isotropic pressure pressurizing device (HIP).
In this sintering step S02, the sintering temperature is in the range of 650 ° C. or higher and 1000 ° C. or lower, the holding time at the sintering temperature is in the range of 0.5 hours or more and 15 hours or less, and the pressurizing pressure is in the range of 10 MPa or more and 200 MPa or less. Be inside.

(Machining process S03)
Next, the obtained sintered body is machined to have a predetermined size. As a result, the sputtering target according to the present embodiment is manufactured.

According to the sputtering target of the present embodiment having the above configuration, the first component composed of one or two kinds of carbides selected from W and Ta, and Si, In, Y, Nb, V, Zn. , Zr, Al, B, Mo, W contains a second component consisting of one or more oxides selected from, and the total content of W, Ta in the first component is 10 atomic% or more. Since it is within the range of 35 atomic% or less, it is possible to form an optical functional film 12 which is excellent in heat resistance and can be satisfactorily etched with an etching solution containing hydrogen peroxide. Further, it is possible to form an optical functional film 12 capable of sufficiently suppressing the reflection of light from a metal thin film or the like.

In the sputtering target of the present embodiment, when the structure is such that granular carbides are dispersed in the matrix of the oxide and the average particle size of the carbides is within the range of 1 μm or more and 150 μm or less, the sputtering target of this sputtering target. It is possible to increase the density and to stably form an optical functional film 12 in which carbides and oxides are uniformly mixed by sputtering.

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

According to the optical functional film 12 of the present embodiment, the first component composed of one or two kinds of carbides selected from W and Ta, Si, In, Y, Nb, V, Zn, Zr, Al and B , Mo, W contains a second component consisting of one or more oxides selected from, and the total content of W, Ta in the first component is in the range of 3 atomic% or more and 11 atomic% or less. Since it is inside, it has excellent heat resistance and can be satisfactorily etched with an etching solution containing hydrogen peroxide. In addition, it is possible to sufficiently suppress the 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 a film is formed on the surface in contact with the Cu film within a thickness range of 25 nm or more and 75 nm or less, the metal wiring film 11 is used. It is possible to reliably suppress the reflection of light.
In the optical functional film 12 of the present embodiment, the sheet resistance of a thickness 50nm is 10 ⁶ Ω / sq. In the following cases, conductivity is ensured and energization can be performed through the optical functional film 12.

Further, in the optical functional film 12 of the present embodiment, the etching rate with the hydrogen peroxide etching solution is 0.3 mm / sec. Above 5.8 mm / sec. When it is within the following range, when it is laminated on the metal wiring film 11, it can be satisfactorily etched together with the metal wiring film 11, and patterning can be efficiently performed.

Further, in the optical functional film 12 of the present embodiment, 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 set to be within the range of 40 or more and 100 or less. If so, the absorption and interference of visible light makes it possible to more reliably suppress the reflection of visible light.
Further, in the optical functional film 12 of the present embodiment, a film is formed on the surface in contact with the Cu film within a thickness range 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 20% or less. In the case of, the optical characteristics do not change significantly even if the heat treatment is performed, and the heat resistance is excellent.

Further, the optical functional film 12 of the present embodiment is an optical functional film 12 formed on a metal wiring film 11 containing Al or Cu, or between a substrate and the metal wiring film 11, and W. The first component consisting of one or two carbides selected from Ta and the oxidation of one or more selected from Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo, W. It is characterized in that it contains a second component made of a substance and has a visible light reflectance of 20% or less when a film is formed in a thickness range of 25 nm or more and 75 nm or less.

Although the embodiments of the present invention have been described above, the present invention is not limited to this, and can be appropriately changed without departing from the technical requirements of the invention.
For example, in the present embodiment, the laminated film having the structure shown in FIG. 1 has been described as an example, but the present invention is not limited to this, and the optical functional film 12 of the present embodiment is formed between the substrate and the metal wiring. It may be a laminated film having a structure of a glass substrate / optical functional film / metal wiring formed. In this case, the light from the glass substrate will be reflected. Further, with this structure, the optical functional film does not need to have conductivity.

The results of the evaluation test for evaluating the action and effect of the sputtering target and the optical functional film according to the present embodiment will be described below.

As shown in Tables 1 and 2, the first component powder consisting of one or two carbides selected from W and Ta, and Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo, A second component powder consisting of one or more oxides selected from W was weighed. 1 kg of the weighed raw material powder and 1.3 kg of a φ5 mm ball were put into a 3 L pot. Next, the raw material powder was mixed with a ball mill device to obtain a raw material powder for sintering. All powders having a purity of 99.9% by mass or more were used.

The average particle size of the first component powder and the second component powder was measured as follows.
Prepare 100 mL of an aqueous solution having a sodium hexametaphosphate concentration of 0.2 vol%, add 10 mg of each raw material powder to this aqueous solution, and use a laser diffraction / scattering method (measuring device: Microtrac MT3000 manufactured by Nikkiso Co., Ltd.) to distribute the particle size (volume). Reference) was measured.
From the obtained particle size distribution (volume basis), the average particle size of the first component powder and the average particle size of the second component powder (D50 diameter) were determined.

Using the above-mentioned raw material powder for sintering, sintering was performed by hot pressing or HIP to obtain a sintered body.
For the hot press, the raw material powder for sintering is filled in a carbon hot press mold (φ135 mm), and the hot press is performed at 830 ° C. at the pressures shown in Tables 1 and 2 for 3 hours in a vacuum to bake. A bunch was made.
For HIP, first, a mixed powder (raw material powder for sintering) was filled in a rubber mold having a diameter of 225 mm, and pressure-molded at 150 MPa with a cold hydrostatic pressure (CIP) device for 5 minutes to prepare a molded body. Then, the molded body was set in the can of SPCC (rolled steel material), and the SPCC was welded. Then, the vacuum was evacuated to 0.001 Pa or less, and then the can was sealed. Sintering was performed at 850 ° C. at the pressures shown in Tables 1 and 2 for 2 hours to prepare a sintered body.

These sintered bodies were machined to a diameter of 125 mm and a thickness of 5 mm, and then attached to a backing plate made of Cu with In solder to prepare a sputtering target. If it is desired to reduce impurity elements, it is preferable to use a raw material powder having a higher purity. Indium oxide powder and zinc oxide powder may be reduced during hot pressing and HIP to precipitate In and Zn, respectively. Therefore, it is preferable to sufficiently apply boron nitride 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.

As described above, the obtained sputtering target and the optical functional film formed by using this sputtering target were evaluated for the following items.

(Composition of sputtering target)
Quantitative analysis of the EPMA device was performed to quantify each metal component and C and O components, and quantification results were obtained. It was confirmed that there was no significant change in the composition at the time of blending the raw materials. For those containing both the carbide of W and the oxide of W, the ratio of the carbide of W and the oxide of W was obtained by performing XPS analysis, and the W in the first component was obtained using the obtained ratio and the quantitative result. And the amount of W in the second component were determined respectively.

(Density ratio of sputtering target)
The volume of the sputtering target was calculated from the dimensions 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 the dimensional density divided by the calculated density is shown in Tables 3 and 4 as the "density ratio". The calculated density was calculated according to the following formula.
Calculated density (g / cm ³ ) = 100 / {first component charge amount (mass%) / first component theoretical density (g / cm ³ ) + second component charge amount (mass%) / second component theoretical density (g / cm 3) g / cm ³ )}

(Sputtering target structure)
An observation sample was collected from the obtained sputtering target, embedded in an epoxy resin, and polished. Then, using an electron probe microanalyzer (EPMA) device, element mapping was performed for a range of 36 μm × 28 μm at a magnification of 3000 times.
From the mapping image of the metal contained in the first component and the mapping image of the metal contained in the second component, the tissue composition of the first component and the second component was observed. Then, the average particle size of the carbide (the average number of circle-equivalent diameters) was calculated and shown in Tables 3 and 4.
Here, FIG. 3 shows the observation results of Example 1 of the present invention, and FIG. 4 shows the observation results of Example 2 of the present invention.

(Specific resistance of sputtering target)
The values measured by the four-probe method using a low resistivity meter (Loresta-GP) manufactured by Mitsubishi Chemical Corporation for the center of the sputtered surface of the obtained sputtering target are shown in the table. The temperature at the time of measurement was 23 ± 5 ° C. (18 ° C. to 28 ° C.), and the humidity was 50 ± 20% (30% to 70%). An ASP probe was used as the probe at the time of measurement.

(Measurement of abnormal discharge frequency)
Ar was flown into the sputter chamber at 50 sccm, and sputtering was performed at ^{5.0 W / cm 2} at DC with a total pressure of 0.67 Pa and a TS distance of 70 mm for 1 hour. The number of abnormal discharges during this spatter was recorded. As a power source, a DC power supply device RPG-50 manufactured by mks was used.

(Evaluation of single membrane)
In the obtained sputtering target, Ar was flowed in the sputtering chamber at 50 sccm, the total pressure in the chamber was 0.67 Pa, the TS distance was 70 mm at DC, and the output shown in Tables 5 and 6 was 20 mm. A film having a thickness of 50 nm was formed on the corner Si substrate. A film was formed in advance under the above conditions, and the adhesion rate of the film was calculated. Then, the film forming time for obtaining the target film thickness (50 nm) was determined. The film thickness was controlled by forming the film for a film forming time of the target film thickness (50 nm) calculated in advance. The obtained films were evaluated in the following (1) to (4).

(1) Analysis of film composition By quantitative analysis of the EPMA device, each metal component and C and O components were quantified and quantification results were obtained. For those containing both the carbide of W and the oxide of W, the ratio of the carbide of W and the oxide of W was obtained by performing XPS analysis, and the W in the first component was obtained using the obtained ratio and the quantitative result. And the amount of W in the second component were determined respectively. 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%. Further, in Comparative Example 4, each metal component and the C, O, N components were quantified, and the ratio of each component was calculated when the total value of the metal component and the C, O, N components was 100 atomic%. ..

(2) Measurement of refractive index and extinction coefficient For a film-formed sample with a film thickness of 50 nm, UVISEL-HR320 (spectral ellipsometry manufactured by Horiba Seisakusho) was used to determine the refractive index in the visible light region (wavelength region of 380 to 780 nm). The extinction index was measured and calculated.

(3) Measurement of resistivity The values measured by the four-probe method using Loresta-GP (manufactured by Mitsubishi Chemical Analytical Co., Ltd.) are shown in Tables 7 and 8. The temperature at the time of measurement was 23 ± 5 ° C. (18 ° C. to 28 ° C.), and the humidity was 50 ± 20% (30% to 70%). A PSP probe was used as the probe at the time of measurement.

(4) Measurement of Etching Rate A film-forming sample having a film thickness of 50 nm was immersed in a commercially available hydrogen peroxide-based etching solution GHP-3 (manufactured by Kanto Chemical Co., Inc.), and the time required for the film to melt was measured. The etching rate was obtained by dividing the time value by the film thickness value. At the time of measurement, the temperature of the etching solution was set to 40 ± 5 ° C. (35 ° C. to 45 ° C.).

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

(Heat resistance test)
The laminated film prepared by measuring the reflectance was heat-treated at 400 ° C. in a nitrogen atmosphere for 10 minutes. The reflectance after the heat treatment was measured in the same manner as immediately after the film formation.

In Comparative Example 1, the sputtering target, ZnO is WC and the second component is a first _component, but contains Y 2 _{O 3,} the content of W are 8.0 atomic%, the deposition The W content in the obtained optical functional film was 2.8 atomic%. In this optical functional film, the reflectance was greatly increased after the heat treatment at 400 ° C., and the heat resistance was insufficient.

In Comparative Example 2, the sputtering target _{contained WC as the first component and Y 2} O ₃ as the second component, but the W content was 39.0 atomic%, and the film was formed. The W content in the optical functional film was 13.6 atomic%. In this optical functional film, the reflectance before heat treatment was relatively large at 35%, and the reflection of visible light of the metal thin film could not be sufficiently suppressed.

In Comparative Example 3, the sputtering target was made of metallic 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 was 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 metallic Cu, and an optical functional film made of copper oxynitride (CuNO) was formed by introducing nitrogen and oxygen during sputtering. In this optical functional film, the sheet resistance became very high. In addition, it was insoluble in the hydrogen peroxide etching solution and could not 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 10 atomic% or more and 35 atomic% or less. It is within the range, and the total content of W and Ta in the first component in the formed optical functional film is within the range of 3 atomic% or more and 11 atomic% or less. In these optical functional films, the reflectance of visible light before the heat treatment was low, and the reflection of visible light of the metal thin film could be sufficiently suppressed. In addition, the reflectance of visible light did not change significantly even after the heat treatment, and the heat resistance was excellent. Further, the etching treatment could be performed satisfactorily with the hydrogen peroxide etching solution.

From the above, according to the example of the present invention, an optical functional film having excellent etching properties and heat resistance due to an etching solution containing hydrogen peroxide and capable of sufficiently suppressing reflection of light from a metal thin film or the like is formed. It was confirmed that it is possible to provide a sputtering target to be filmed and an optical functional film.

The sputtering target of the present embodiment is suitably applied to a step of forming a low reflectance film provided on an electrode (metal film) for sensing in a projected capacitive touch panel and a black matrix in a flat panel display. ..

12 Optical functional film

Claims

The first component consisting of one or two carbides selected from W and Ta, and one or more selected from Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo and W. Containing a second component consisting of the oxide of
A sputtering target characterized in that the total content of W and Ta in the first component is in the range of 10 atomic% or more and 35 atomic% or less.
The first aspect of the present invention is characterized in that the structure is such that the granular carbides are dispersed in the matrix of the oxide, and the average particle size of the carbides is in the range of 1 μm or more and 150 μm or less. Sputtering target.
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 0.1 Ω · cm or less.
The first component consisting of one or two carbides selected from W and Ta, and one or more selected from Si, In, Y, Nb, V, Zn, Zr, Al, B, Mo and W. Containing a second component consisting of the oxide of
An optical functional film characterized in that 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.
The optical functional film according to claim 5, wherein the visible light reflectance is 20% or less when a film is formed on the surface in contact with the Cu film within a thickness range of 25 nm or more and 75 nm or less.
The sheet resistance of a thickness of 50nm is 10 6 Ω / sq. The optical functional film according to claim 5 or 6, wherein the optical functional film is as follows.
Etching rate with hydrogen peroxide etching solution is 0.3 mm / sec. Above 5.8 mm / sec. The optical functional film according to any one of claims 5 to 7, wherein the optical functional film is within the following range.
Claim 5 to claim 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. 8. The optical functional film according to any one of 8.
Claimed from claim 5, wherein a film is formed on the surface in contact with the Cu film within a thickness range 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 20% or less. Item 9. The optical functional film according to any one of Items 9.