TW202208653A - Sputtering target, method for producing sputtering target and optical functional film - Google Patents

Abstract

This sputtering target comprises a zinc oxide phase and one or more metal phases that are selected from among Nb, W and Ti, while having a density ratio of 80% or more; and the standard deviation of the respective contents of the one or more metal elements selected from among Nb, W and Ti, said contents being measured at a plurality of sites in the sputtering surface, is 5 mass% or less.

Description

Sputtering target, manufacturing method of sputtering target and optical function film

The present invention relates to, for example, a sputtering target used for an optically functional film that is laminated on a metal thin film or the like and reduces light reflection from the metal thin film or the like, a method for producing the sputtering target, and an optically functional film. This application claims priority based on Japanese Patent Application No. 2020-099577 for which it applied to Japan on June 8, 2020, the content of which is incorporated herein by reference.

In recent years, as an input means for portable terminal devices and the like, a touch panel of a projection type electrostatic capacitance method has been adopted. In the touch panel of this method, in order to detect the touched position, it is necessary to form electrodes for sensing. The sensing electrodes 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 in a lattice shape. Here, when a metal film is used for the electrodes of the touch panel, since the metal film has metallic luster, the electrode pattern can be seen from the outside. Therefore, it is considered to form a low reflectance film having a low reflectance of visible light on the metal thin film, thereby reducing the visibility of the electrode.

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

In addition, regarding the solar cell 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 the back electrode, a metal film such as molybdenum (Mo) or silver (Ag) is used. When the solar cell panel of this state is viewed from the back side, the metal film of the back electrode can be visually recognized. Therefore, it is thought that the visibility of the back surface electrode can be lowered by forming the above-mentioned low-reflectance film on the back surface electrode.

Here, for example, in Patent Document 1, as a sputtering target for forming the above-mentioned low reflectance film (optical function film), one containing an oxide and an oxynitride is proposed.

Here, in the sputtering target described in Patent Document 1, sintering is performed at a temperature of 1000° C. or higher, but when zinc oxide (ZnO) is contained as an oxide, the zinc oxide (ZnO) is sublimated or oxidized by the contained metal element. Zinc is reduced and the resulting Zn is sublimated, causing problems such as uneven composition and lowering of density.

In addition, the above-mentioned optical function film is required to have durability so that the optical properties do not change significantly at the time of manufacture and use. For example, when a heating step is performed after film formation, heat resistance is required. Moreover, when forming a wiring pattern by etching, since an alkali is used for developing and peeling a resist film, alkali resistance is required. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 6161095

[The problem to be solved by the invention]

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a sputtering target of an optically functional film which can efficiently and stably form a film having excellent heat resistance and alkali resistance, and which can sufficiently suppress light reflection from a metal thin film or the like, and the A method for producing a sputtering target and an optical functional film. [means to solve the problem]

In order to solve the above problems, one aspect of the present invention is a sputtering target, which is characterized by comprising one or more metal phases and zinc oxide phases selected from Nb, W, and Ti, and having a density ratio of 80% or more, The standard deviation of the individual content of the metal element consisting of one or two or more selected from Nb, W, and Ti measured at a plurality of locations on the sputtered surface was 5 mass % or less.

According to the sputtering target of this configuration, since it contains one or more metal phases selected from Nb, W, and Ti, and a zinc oxide phase, it is possible to form an optically functional film having excellent optical properties and excellent heat resistance and alkali resistance. . Furthermore, since the density ratio is set to 80% or more, the occurrence of abnormal discharge during sputtering can be suppressed. In addition, since the standard deviation of the individual content of metal elements consisting of one or more selected from Nb, W, and Ti measured at a plurality of locations on the sputtered surface is 5 mass % or less, it is possible to form a reflection film. Optically functional film with less uneven rate.

Here, in the sputtering target of one aspect of the present invention, the average particle area of the pores is preferably 5 μm ² or less. In this case, since the average particle area of the pores is limited to 5 μm ² or less, the occurrence of abnormal discharge due to the pores during sputtering can be suppressed, and the optical function film can be formed stably.

In addition, in the sputtering target of one aspect of the present invention, preferably one or more metals M selected from Al, Si, Ga, In, Sn, Ti, Nb, Zr, Mo, Ta, W, Y are included The total content of the above-mentioned metal M is in the range of 0.1 mass % or more and 40 mass % or less, when all metal elements are taken as 100 mass %. In this case, since the oxide of the above-mentioned metal M is contained in the range of 0.1 mass % or more and 40 mass % or less, when the total metal element is taken as 100 mass %, the heat resistance of the formed optical function film can be further improved. and alkali resistance.

Furthermore, in the sputtering target of one aspect of the present invention, it is preferable that the ratio of the standard deviation of the specific resistance values measured at a plurality of locations on the sputtering surface divided by the average value is 100% or less. In this case, since the unevenness of the specific resistance value of the sputtered surface is suppressed, the occurrence of abnormal discharge during sputtering can be suppressed, and the optical function film can be stably formed.

Furthermore, in the sputtering target of one aspect of the present invention, it is preferable that the total content of Nb, W, and Ti is 50 mass % or more with respect to the whole including O and C. In this case, since the total content of Nb, W, and Ti is 50 mass % or more with respect to the whole including O and C, the specific resistance is sufficiently reduced, and the occurrence of abnormal discharge can be suppressed. In addition, the heat resistance and alkali resistance of the formed optical function film can be further improved.

Furthermore, in the sputtering target of one aspect of the present invention, it is preferable to further contain C in the range of 1 mass % or more and 10 mass % or less with respect to the whole. In this case, by containing 1 mass % or more of C with respect to the whole, the heat resistance and alkali resistance of the optical function film formed into a film can be further improved. And since the C content is limited to 10 mass % or less with respect to the whole, the etching property of the optical function film formed into a film can be ensured.

A method for manufacturing a sputtering target according to an aspect of the present invention is characterized by the method for manufacturing a sputtering target comprising one or more metal phases selected from Nb, W, and Ti, and a zinc oxide phase, comprising: using water A solvent with a concentration of 30% by volume or more, a metal powder with an average particle size of 5 μm or more selected from one or more of Nb, W, and Ti is mixed with zinc oxide powder with an average particle size of 1 μm or less. The granulated powder production step of drying to obtain granulated powder, and the sintering step of sintering the obtained granulated powder by heating and pressing at a temperature of 1000° C. or less and a pressure of 145 MPa or more.

According to the manufacturing method of the sputtering target of this structure, since the solvent with a concentration of water of 30% by volume or more is used, the metal having an average particle size of 5 μm or more selected from Nb, W, and Ti, or two or more kinds of metals are used. The powder is mixed with zinc oxide powder with an average particle size of 1 μm or less and dried to obtain a granulated powder. Therefore, the granulation of the metal powder with a large particle size and the zinc oxide powder with a small particle size can be uniformly mixed. pink. Therefore, in the subsequent sintering step, the sublimation of zinc oxide or the reduction reaction of zinc oxide can be suppressed, gas generation can be suppressed, density can be increased, and at the same time, the occurrence of uneven composition can be suppressed. Moreover, since the granulated powder obtained by heating and pressurizing at a temperature of 1000° C. or less and a pressure of 145 MPa or more is provided for sintering and sintering, the density can be sufficiently increased.

Here, in the manufacturing method of the sputtering target of an aspect of this invention, before the said sintering process, the shaping|molding process of pressurizing the said granulated powder at normal temperature and shaping|molding may be provided. In this case, since the molding step of pressurizing the granulated powder at normal temperature and molding is provided, a sintered body having a further increased density can be obtained.

Moreover, in the manufacturing method of the sputtering target of one aspect of the present invention, in the granulated powder manufacturing step, in addition to the metal powder and the zinc oxide powder, the average particle diameter may be mixed in a range of 0.1 μm or more and 12 μm or less. Oxide powder of one or more metals M selected from Al, Si, Ga, In, Sn, Ti, Nb, Zr, Mo, Ta, W, and Y. In this case, a sputtering target containing an oxide of one or two or more metals M selected from Al, Si, Ga, In, Sn, Ti, Nb, Zr, Mo, Ta, W, and Y can be produced. Furthermore, since the average particle diameter of the oxide powder of metal M is in the range of 0.1 μm or more and 12 μm or less, the density can be sufficiently increased, and the occurrence of abnormal discharge caused by the oxide of the metal M during sputtering can be suppressed.

Furthermore, in the manufacturing method of the sputtering target of one aspect of this invention, it is preferable that the average particle diameter of the said zinc oxide powder is 100 nm or less. In this case, the density can be further improved.

Moreover, in the manufacturing method of the sputtering target of one aspect of this invention, it is preferable that the average particle diameter of the said metal powder is 10 micrometers or more. In this case, the density can be further improved.

The optical function film of one aspect of the present invention is characterized by comprising an optical function film of metal and zinc oxide selected from one or two or more selected from Nb, W, Ti, and selected from Nb, W, Ti. The standard deviation of the individual content of one or more metal elements is 5 mass % or less.

According to the optical function film of this structure, since it contains the metal which consists of 1 type or 2 or more types selected from Nb, W, and Ti, and zinc oxide, it is excellent in optical properties, and is excellent in heat resistance and alkali resistance. And since the standard deviation of the individual content of the metal element which consists of 1 type or 2 or more types selected from Nb, W, and Ti is 5 mass % or less, the unevenness of a reflectance becomes small.

Here, in the optical function film of one aspect of the present invention, one or more metals selected from Al, Si, Ga, In, Sn, Ti, Nb, Zr, Mo, Ta, W, and Y may be included. M oxides. In this case, since the oxide of metal M selected from one or more of Al, Si, Ga, In, Sn, Ti, Nb, Zr, Mo, Ta, W, and Y is contained, the heat resistance can be further improved. and alkali resistance. [Inventive effect]

According to one aspect of the present invention, it is possible to provide a sputtering target capable of efficiently and stably forming an optically functional film which is excellent in heat resistance and alkali resistance, and which can sufficiently suppress reflection of light from a metal thin film, etc., and manufacture of the sputtering target. Methods and optically functional films.

Hereinafter, the sputtering target, the manufacturing method of the sputtering target, and the optical function film of the present embodiment will be described with reference to the accompanying drawings.

As shown in FIG. 1 , the optical function film 12 of the present embodiment is formed by being laminated on the metal wiring film 11 formed on the surface of the substrate 1 . Here, the metal wiring film 11 is composed of aluminum, an aluminum alloy, copper, or a copper alloy, which is a metal excellent in electrical conductivity, and is composed of copper in the present embodiment. Since the metal wiring film 11 has metallic luster, it reflects visible light and can be viewed from the outside.

The optical function film 12 of the present embodiment is provided in order to suppress the reflection of visible light by the laminated metal wiring film 11 . The optical function film 12 of the present embodiment contains one or more metals selected from Nb, W, and Ti, and zinc oxide. And the standard deviation of the individual content of the metal element which consists of 1 type or 2 or more types selected from Nb, W, and Ti is 5 mass % or less. In addition, the optical function film 12 of the present embodiment may also include oxides of one or more metals M selected from Al, Si, Ga, In, Sn, Ti, Nb, Zr, Mo, Ta, W, and Y. . Furthermore, the optical function film 12 of the present embodiment is preferably selected from Nb, W, and Ti in an amount of 50% by mass to 80% by mass, and Zn is preferably 10% by mass or more and 30% by mass or less in total. It is contained, and the rest is composed of oxygen and unavoidable impurities. If necessary, it may further contain one or two or more selected from Al, Si, Ga, In, Sn, Zr, Mo, Ta, and Y in a total of 40 mass % or less. The metal M includes C in the range of 10% by mass or less.

Here, in the above-mentioned optical function film 12, as shown in FIG. 2, the content of metal elements selected from one or two or more kinds selected from Nb, W, and Ti is measured at five locations on the film surface, and the metal elements are calculated. The standard deviation of the content. In detail, when the film surface of the optical function film 12 shown in FIG. 2 is rectangular, the measurement site is a point of intersection where the diagonal lines of the opposite corners of the film surface intersect and the distance between the corners on the diagonal lines. It is the 5th part of the 4th point within 10% of the full length of the diagonal. When the film surface of the optical function film 12 is circular, the distance between the center of the film surface at the measurement site and the two straight lines that pass through the center of the film surface and are orthogonal to each other, the outer peripheral portion is the position within 10% of the full length of the diagonal line 4 points out of 5. The individual contents of Nb, W, and Ti measured to obtain the standard deviation also include Nb, W, and Ti contained in the oxide of metal M. Moreover, the standard deviation of the individual content of metal elements selected from one or more of Nb, W, and Ti in the optical function film 12 is preferably 3 mass % or less, more preferably 1 mass % or less.

In addition, the said optical function film 12 is formed into a film using the sputtering target of this embodiment. The sputtering target of the present embodiment will be described below.

The sputtering target of the present embodiment includes one or two or more metal phases and zinc oxide phases selected from Nb, W, and Ti. Moreover, the density ratio of the sputtering target of this embodiment is 80% or more. Furthermore, the standard deviation of the individual content of metal elements selected from one or more of Nb, W, and Ti measured at a plurality of locations on the sputtering surface of the sputtering target of the present embodiment is 5 mass % or less. .

Here, in the sputtering target of the present embodiment, the total content of Nb, W, and Ti is preferably 50% by mass or more. In addition, the sputtering target of the present embodiment may also include oxidation of one or more metals M selected from Al, Si, Ga, In, Sn, Ti, Nb, Zr, Mo, Ta, W, and Y. The total content of the aforementioned metals M is in the range of 0.1 mass % or more and 40 mass % or less, when all metal elements are taken as 100 mass %. The total content of the above-mentioned Nb, W, and Ti also includes Nb, W, and Ti contained in the oxide of the metal M described above. The total content of the metal M is the total content of the metal M in the oxide of the metal M, and does not include the amounts of Nb, W, and Ti in the metal phase. In addition, in the sputtering target of this embodiment, C may be contained in the range of 1 mass % or more and 10 mass % or less. In addition, in the sputtering target of the present embodiment, it is preferable that one or more selected from Nb, W, and Ti are contained in a total amount of 50 mass % or more and 80 mass % or less, and Zn is 10 mass % or more and 30 mass % or less in total. The rest is composed of oxygen and unavoidable impurities, and may further contain one or more metals selected from Al, Si, Ga, In, Sn, Zr, Mo, Ta, and Y in a total amount of 40 mass % or less according to need. M, and C is included in the range of 10 mass % or less.

In addition, in the sputtering target of the present embodiment, the average particle area of the pores is preferably 5 μm ² or less. Furthermore, in the sputtering target of the present embodiment, it is preferable that the ratio of the standard deviation of the specific resistance values measured at a plurality of locations on the sputtering surface divided by the average value is 100% or less.

For the sputtering target of the present embodiment, the difference between the phase composition, density ratio, standard deviation of the content of each metal element in the sputtering surface, average particle area of pores, composition, and specific resistance value in the sputtering surface is shown below. for the reasons stated above.

(phase composition) The sputtering target of the present embodiment contains one or more metal phases and zinc oxide phases selected from Nb, W, and Ti. Thereby, the optical function film 12 of this embodiment can be formed into a film by sputtering. The optical function film 12 is excellent in optical properties, and is excellent in heat resistance and alkali resistance. The area ratio (percentage) of metal phase/(metal phase+zinc oxide phase) is preferably 10-95%, more preferably 20-80%, still more preferably 30-70%. The area of each phase was measured by the following method. With respect to the sample collected from the sputtering target, an electron probe microanalyzer (EPMA) apparatus was used to take a group image (COMPO image) to perform elemental mapping. For the elemental map image of zinc, the image processing software Image J was used to binarize the luminance. Calculate the area of the zinc-containing region. The area of the zinc-containing region was set as the area of the zinc oxide phase. Next, for the elemental mapping phases of Nb, W, Ti, and O, a binarized image of the region containing Nb, W, Ti, and O is obtained. The areas containing Nb, W, and Ti are black, the areas containing O are white, and the surrounding areas are transparent, and image processing is performed respectively. A region containing Nb, W, and Ti as metal components is obtained by overlapping the binarized image of the region containing Nb, W, and Ti with the binarized image of the region containing O. In the obtained image, the area of the region containing Nb, W, and Ti as metal components was calculated. That is, in the region containing Nb, W, and Ti, the area of the region not containing O is the area of the metal phase.

(density ratio) In the sputtering target of the present embodiment, the density ratio is 80% or more. Thereby, the occurrence of abnormal discharge during sputtering can be suppressed, and the optical function film 12 of the present embodiment can be stably formed. In addition, the density is preferably 85% or more, more preferably 90% or more. The upper limit of the density ratio is preferably 100% or less.

(Standard deviation of the content of each metal element in the sputtered surface) In the sputtering target of the present embodiment, the standard deviation of the individual content of metal elements selected from Nb, W, and Ti at a plurality of locations on the sputtering surface is 5 mass % or less. In addition, when at least one metal element among Nb, W, and Ti is contained, the standard deviation of the contained metal element is an index indicating the degree of uneven content of the metal element, and is set to 5 mass % or less. The respective contents of Nb, W, and Ti measured to obtain the standard deviation also include Nb, W, and Ti contained in the oxide of the metal M. Thereby, the optical function film 12 with less unevenness in reflectance can be formed. As the reflectance unevenness of the optical function film 12, the standard deviation of the reflectance measured at plural places is preferably 3.0% or less, and preferably 2.5% or less. Moreover, the standard deviation of the individual content of the metal element consisting of one or two or more selected from Nb, W, and Ti in the sputtered surface is preferably 4 mass % or less, more preferably 3 mass % or less.

Here, in this embodiment, the standard deviation of the content of each metal element in the sputtering surface is preferably connected to the opposite corners of the sputtering surface when, for example, the sputtering surface of the sputtering target is rectangular as shown in FIG. 3 . The intersection (1) where the diagonal lines intersect and the 5 points (2), (3), (4), and (5) that are within 10% of the full length of the diagonal from the corner of each diagonal , measure the content of each metal element, and calculate the standard deviation.

Moreover, when the sputtering surface of the sputtering target is circular as shown in FIG. 4, it is preferable that the distance between the center (1) of the sputtering surface and the outer periphery of the two straight lines that pass through the center of the sputtering surface and are orthogonal to each other The part is 5 points (2), (3), (4), and (5) of the position within 10% of the full length of the diagonal line, and the content of each metal element is measured, and the standard deviation is calculated.

Furthermore, when the sputtering surface of the sputtering target is a cylindrical surface as shown in FIGS. 5A and 5B , it is preferable that the two ends A, B and the center C in the direction of the axis O be separated by 90° in the circumferential direction. (1), (2), (3), (4) 12 points, the content of each metal element was measured, and the standard deviation was calculated.

(Average Particle Area of Holes) In the sputtering target of the present embodiment, when the average particle area of holes is 5 μm ² or less, the occurrence of abnormal discharge caused by holes during sputtering can be suppressed, and the optical film can be formed stably. Functional film 12 . In addition, the average particle area of the pores is preferably 4 μm ² or less, more preferably 3 μm ² or less.

(composition) In the sputtering target of the present embodiment, when the total content of Nb, W, and Ti is 50% by mass or more, the specific resistance of the sputtering target can be sufficiently reduced, the occurrence of abnormal discharge during sputtering can be suppressed, and stable film formation can be achieved Optical functional film 12 . And it can further improve the heat resistance and alkali resistance of the optical function film 12 formed into a film. In addition, the lower limit of the total content of Nb, W, and Ti is preferably 55% by mass or more, more preferably 60% by mass or more. Furthermore, the upper limit of the total content of Nb, W, and Ti is preferably 90% by mass or less, more preferably 80% by mass or less.

In addition, in the sputtering target of the present embodiment, one or two or more oxides of metal M selected from Al, Si, Ga, In, Sn, Ti, Nb, Zr, Mo, Ta, W, and Y are included, When the total content of the metal M is in the range of 0.1 mass % or more and 40 mass % or less, when all metal elements are taken as 100 mass %, the heat resistance and alkali resistance of the optical function film 12 to be formed can be further improved. At the same time, the occurrence of abnormal discharge caused by the oxide of metal M during sputtering can be suppressed. In addition, when the oxide of metal M selected from Al, Si, Ga, In, Sn, Ti, Nb, Zr, Mo, Ta, W, and Y is contained in one or two or more kinds, all metal elements are regarded as 100 mass %, the lower limit of the total content of the metal M is more preferably 1 mass % or more, and still more preferably 5 mass % or more. And the upper limit of the total content of the metal M is more preferably 35 mass % or less, and still more preferably 30 mass % or less.

In addition, in the sputtering target of this embodiment, when C is contained in the range of 1 mass % or more and 10 mass % or less, the heat resistance and alkali resistance of the optical function film 12 formed into a film can be further improved. Moreover, in order to exhibit the above-mentioned effects by including C, the lower limit of the C content is more preferably 2 mass % or more, and still more preferably 3 mass % or more. In addition, in order to maintain the low reflectance at the time of metal lamination, the upper limit of the C content is preferably 7% by mass or less, more preferably 5% by mass or less.

(specific resistance value) In addition, in the sputtering target of the present embodiment, when the ratio of the standard deviation of the specific resistance values measured at a plurality of locations on the sputtering surface divided by the average value is 100% or less, the occurrence of abnormal discharge during sputtering can be suppressed, and further Optically functional films can be stably formed. In addition, the ratio of the standard deviation of the specific resistance values measured at a plurality of locations on the sputtered surface divided by the average value is more preferably 100% or less, and more preferably 50% or less. The measurement site of the specific resistance value is the same as the measurement site of the metal element content in FIG. 3 , FIG. 4 , FIG. 5A and FIG. 5B .

Next, the manufacturing method of the sputtering target of the present embodiment will be described with reference to FIG. 6 .

In the present embodiment, as shown in FIG. 6 , a granulated powder production step S01 is provided for obtaining granulated powder by mixing one or more metal powders selected from Nb, W and Ti with zinc oxide powder using a solvent, A sintering step S02 of pressing and heating the obtained granulated powder to sinter, and a machining step S03 of machining the obtained sintered body.

(granulated powder production step S01) In the granulated powder production step S01, metal powder with an average particle size of 5 μm or more selected from one or more of Nb, W, and Ti, and zinc oxide powder with an average particle size of 1 μm or less are prepared. Next, these metal powders and zinc oxide powders are mixed with a solvent having a water concentration of 30% by volume or more and dried to obtain granulated powder. Examples of the solvent include pure water, a mixture of pure water and ethanol, and the like.

Here, the average particle size of the metal powder selected from one or two or more of Nb, W, and Ti is set to 5 μm or more, and the average particle size of the zinc oxide powder is set to 1 μm or less, so that the sintering can be suppressed. Gas generation due to the sublimation of zinc oxide and metallic zinc can increase the density of the sintered body. In addition, by mixing the metal powder and the zinc oxide powder with a solvent with a water concentration of 30% by volume or more, the surface tension of the solvent during the slurry drying causes the powder to aggregate, and the metal powder and zinc oxide powder after drying can be suppressed. The separation can suppress the unevenness of the composition.

Further, the lower limit of the average particle diameter of the metal powder composed of one or two or more selected from Nb, W, and Ti is preferably 7 μm or more, and more preferably 10 μm or more. In addition, the upper limit of the average particle size of the metal powder is preferably 20 μm or less, more preferably 18 μm or less. In addition, the upper limit of the average particle size of the zinc oxide powder is preferably 500 nm or less, more preferably 100 nm or less. Further, the lower limit of the average particle size of the zinc oxide powder is preferably 30 nm or more, more preferably 50 nm or more. In addition, the water concentration in the solvent is preferably 50% by volume or more, more preferably 80% by volume or more.

Here, when the sputtering target contains an oxide of one or more metals M selected from Al, Si, Ga, In, Sn, Ti, Nb, Zr, Mo, Ta, W, and Y, the In the particle powder production step S01, in addition to the above-mentioned metal powder and zinc oxide powder, it is preferable to use a solvent with a concentration of water of 30% by volume or more mixed with an average particle size of 0.1 μm or more and 12 μm or less. Al, Si, Ga , In, Sn, Ti, Nb, Zr, Mo, Ta, W, Y selected one or more metal M oxide powder to make granulated powder. By setting the average particle diameter of the oxide powder of metal M to be 0.1 μm or more, the density of the sintered body can be improved. On the other hand, by setting the average particle diameter of the oxide powder of the metal M to be 12 μm or less, the occurrence of abnormal discharge due to the oxide of the metal M during sputtering can be suppressed. In addition, the lower limit of the average particle diameter of the oxide powder of the metal M is preferably 0.3 μm or more, and more preferably 0.5 μm or more. In addition, the upper limit of the average particle size of the oxide powder of the metal M is preferably 10 μm or less, more preferably 7 μm or less. When the sputtering target contains C, in the granulated powder production step S01, it is preferable to mix C powder in addition to the metal powder, zinc oxide powder, and oxide powder of metal M described above. The average particle size of the C powder is preferably 2 to 10 μm. The mixing ratio of the metal powder, the zinc oxide powder, the oxide powder of the metal M, and the C powder is adjusted to obtain the desired composition of the sputtering target. The addition amount of the solvent is preferably 1 to 10 times the amount of the raw material powder (metal powder, zinc oxide powder, oxide powder of metal M, and C powder).

(Sintering step S02) Next, the above-mentioned granulated powder is sintered while being heated under pressure to obtain a sintered body. The sintering temperature in this sintering step S02 is set to 1000° C. or lower, and the pressing pressure is set to be 145 MPa or more. Here, sublimation of zinc oxide and metallic zinc can be suppressed by setting the sintering temperature to be 1000° C. or lower. In addition, by setting the pressing pressure to be 145 MPa or more, the density can be improved. In addition, the upper limit of the sintering temperature is preferably 950°C or lower, more preferably 900°C or lower. On the other hand, the lower limit of the sintering temperature is preferably 600°C or higher, more preferably 700°C or higher. In addition, the lower limit of the pressing pressure is preferably 150 MPa or more, more preferably 155 MPa or more. On the other hand, the upper limit of the pressing pressure is preferably 200 MPa or less, and more preferably 170 MPa or less.

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

According to the sputtering target of the present embodiment configured as described above, since one or two or more metal phases and zinc oxide phases selected from Nb, W, and Ti are included, it is possible to form a film with excellent optical properties, heat resistance and Optical function film 12 with excellent alkali resistance. Furthermore, since the density ratio is set to 80% or more, the occurrence of abnormal discharge during sputtering can be suppressed. In addition, since the standard deviation of the individual content of metal elements consisting of one or two or more selected from Nb, W, and Ti measured at a plurality of locations on the sputtered surface is set to 5 mass % or less, it is possible to form a film. The optical function film 12 with small reflectance unevenness.

In the sputtering target of the present embodiment, when the average particle area of the pores is 5 μm ² or less, the occurrence of abnormal discharge due to the pores during sputtering can be suppressed, and the optical function film 12 can be stably formed.

In addition, in the sputtering target of the present embodiment, one or two or more oxides of metal M selected from Al, Si, Ga, In, Sn, Ti, Nb, Zr, Mo, Ta, W, and Y are included, When the total content of metal M is in the range of 0.1 mass % or more and 40 mass % or less, when all metal elements are taken as 100 mass %, the heat resistance and alkali resistance of the optical function film 12 to be formed can be further improved.

In addition, in the sputtering target of the present embodiment, when the ratio of the standard deviation of the specific resistance values measured at a plurality of locations on the sputtering surface divided by the average value is 100% or less, the occurrence of abnormal discharge during sputtering can be suppressed, and further Optically functional films can be stably formed.

Moreover, in the sputtering target of the present embodiment, when the total content of Nb, W, and Ti is 50 mass % or more, the specific resistance is sufficiently low, and the occurrence of abnormal discharge during sputtering can be further suppressed. In addition, the heat resistance and alkali resistance of the optical function film 12 to be formed can be further improved.

Furthermore, in the sputtering target of the present embodiment, when C is contained in the range of 1 mass % or more and 10 mass % or less, the heat resistance and alkali resistance of the optically functional film 12 to be formed can be further improved, and at the same time, the formation can be ensured. Etchability of the optical function film 12 of the film.

According to the manufacturing method of the sputtering target of the present embodiment, a solvent having an average particle size of 5 μm or more selected from Nb, W, and Ti is prepared by using a solvent with a concentration of water of 30% by volume or more. The metal powder is mixed with zinc oxide powder with an average particle size of 1 μm or less, and the granulated powder is obtained by drying the solvent to obtain the granulated powder production step S01, so the metal powder with larger particle size and the zinc oxide with smaller particle size can be obtained. Granulated powder that is evenly mixed with powder. Therefore, in the subsequent sintering step, the sublimation of zinc oxide and the reduction reaction of zinc oxide can be suppressed, gas generation can be suppressed, density can be increased, and at the same time, the occurrence of uneven composition can be suppressed. In addition, since the obtained granulated powder is heated at a temperature of 1000° C. or lower and a pressure of 145 MPa or more and is sintered with a sintering step S02 , the density can be sufficiently increased.

In the manufacturing method of the sputtering target of the present embodiment, in the granulated powder production step S01, in addition to the metal powder and the zinc oxide powder, Al, Si, Ga having an average particle size in the range of 0.1 μm or more and 12 μm or less is mixed. , In, Sn, Ti, Nb, Zr, Mo, Ta, W, Y selected one or more kinds of metal M oxide powder, can be produced from Al, Si, Ga, In, Sn, Ti, A sputtering target for oxides of metal M selected from one or more of Nb, Zr, Mo, Ta, W, and Y. Furthermore, since the average particle diameter of the oxide powder of the metal M is in the range of 0.1 μm or more and 12 μm or less, the density can be sufficiently increased, and the occurrence of abnormal discharge caused by the oxide of the metal M during sputtering can be suppressed.

In the manufacturing method of the sputtering target of the present embodiment, the average particle size of the zinc oxide powder is 100 nm or less, or the average particle size of the metal powder made of one or more selected from Nb, W, and Ti is 10 μm In the above case, the density can be further improved.

The optical function film 12 according to the present embodiment contains metal and zinc oxide of one or two or more selected from Nb, W, and Ti, and thus has excellent optical properties and is excellent in heat resistance and alkali resistance. Furthermore, since the standard deviation of the individual content of the metal element consisting of one or two or more selected from Nb, W, and Ti is 5 mass % or less, the variation in reflectance is reduced.

In the optical function film 12 of the present embodiment, when an oxide of metal M selected from Al, Si, Ga, In, Sn, Ti, Nb, Zr, Mo, Ta, W, and Y is contained in one or two or more kinds , can further improve heat resistance and alkali resistance.

The embodiment of the present invention has been described above, but the present invention is not limited to this, and can be appropriately changed within the scope of not departing from the technical requirements of the present invention. In the present embodiment, the sintering step is performed after the granulated powder production step, but it is not limited to this, and the granulated powder may be press-molded at room temperature between the granulated powder production step and the sintering step. In the forming step, the obtained formed article is sintered. The pressing pressure in the forming step is preferably 100 MPa or more and 175 MPa or less.

In addition, the present embodiment is described by the structure of forming the optical function film 12 of the present embodiment by laminating the metal wiring film 11 formed on the surface of the substrate 1 as shown in FIG. 1 , but it is not limited to this, and The optical function film 12 is formed on the surface of the substrate 1 , and the metal wiring film 11 is laminated on the optical function film 12 . In this case, the reflection from the substrate 1 can be reduced at the same time. [Example]

Hereinafter, the results of evaluation tests for evaluating the effects of the sputtering target, the manufacturing method of the sputtering target, and the optical function film of the present invention will be described.

The metal powders, zinc oxide powders, various metal oxide powders, and C powders described in Tables 5 to 8 were weighed to a total of 1 kg at the ratios described in Tables 1 to 4. 1kg of the raw material powder, 3kg of φ5mm zirconia balls, and 1L of the solvent with the water concentration described in Tables 5-8 were put into a pot with a capacity of 10L, and mixed with a ball mill for 16 hours. Next, the mixed powder was dried and sieved with a 250 μm mesh to obtain granulated powder. In addition, the solvent is a mixed solution of pure water and ethanol, and the water concentration column in Tables 5 to 8 describes the water concentration value in the mixed solution of pure water and ethanol when the solvent 1 L is only pure water as 100% water concentration. The dry mixing is described as "dry".

The obtained granulated powder was filled into a rubber mold with a diameter of 250 mm. Next, CIP (Cold Isostatic Pressing) was performed at a pressure of 150 MPa to obtain a molded body. The obtained formed body was put into a 220 mm diameter steel tank and evacuated at 300°C. Next, the molded body was sealed in a can, and maintained at the temperature and pressure described in Tables 5 to 8 for 3 hours, and subjected to HIP (Hot Isostatic Pressing) to obtain a sintered body. The obtained sintered body was machined into φ125 mm×thickness t5 mm, and was bonded to a Cu backing plate with In solder to obtain a sputtering target.

In addition, the average particle size of the raw material powder was prepared by preparing 100 mL of an aqueous solution of sodium hexametaphosphate concentration of 0.2%, adding 10 mg of the raw material powder to the aqueous solution, and using a laser diffraction scattering method (measuring device: Nikkiso Co., Ltd. make, Microtrac MT3000) to determine particle size distribution. The arithmetic mean diameter (volume mean diameter) was calculated from the obtained particle diameter distribution, and described in Tables 5 to 8 as the mean particle diameter.

As described above, the following items were evaluated about the obtained sputtering target and the optically functional film formed using the sputtering target.

(metallic phase) A sample was collected from the obtained sputtering target and analyzed by XRD. When the peaks belonging to Nb phase ID: 01-073-3816, W phase ID: 01-004-0806, and Ti phase: 00-044-1294 were obtained, it was determined that each metal phase was present. When a peak belonging to the ZnO phase ID: 00-036-1451 was obtained, it was determined that the ZnO phase was present. As a result, in Examples 1 to 61 of the present invention, a metal phase of any one or more of Nb, W, and Ti (one or more of a Nb phase, a W phase, and a Ti phase) and a ZnO phase were confirmed. Moreover, the obtained film was analyzed by XPS. From the peaks of Nb: 3d orbital, W: 4f orbit, Ti: 2p orbit, and Zn: 2p orbit, in Examples 1 to 61 of the present invention, it was confirmed that metal phases derived from any one or more of Nb, W, Ti and The peaks of the ZnO phase.

(Composition of sputtering target) A sample was collected from the obtained sputtering target, dissolved with acid or alkali, and then quantitatively quantified by ICP-AES. In addition, with respect to C, the quantification of C was carried out by a gas analyzer of LECO. The content of each element with respect to the entirety of C and O is shown in the "sputtering target composition" column of Tables 9 to 12. In addition, when the oxide of metal M is contained, all metal elements are made into 100 mass %, and the content of metal M is shown in the column of "Ratio of metal element M in all metal elements" of Tables 9-12. In addition, since Inventive Example 15 contains metals Nb and Nb oxides, Inventive Example 37 contains metals W and W oxides, and Inventive Example 50 contains metals Ti and Ti oxides, these are referred to as metal oxides. The component amounts were also added to the metal element contents in the column of "sputtering target composition" (represented by "*" in Tables 9, 10, and 11). Therefore, the amount of the metal component with respect to the metal oxide is calculated in both the column of "sputtering target composition" and the column of "ratio of metal element M in all metal elements". That is, the amounts of Nb, W, and Ti in the column of "sputtering target composition" include the amounts of Nb, W, and Ti in the metal oxide. In addition, regarding the metal components of the metal oxides, the quantitative values of the metal components of Nb, W, and Ti derived from the oxides were used based on the semi-quantitative analysis results of the XPS apparatus. That is, the amounts of Nb, W, and Ti in the column of "Ratio of Metal Element M in All Metal Elements" are the amounts of Nb, W, and Ti in the metal oxide.

(density ratio of sputtering target) The volume was calculated from the size of the resulting target, and the density was calculated by dividing the weight by the volume. Furthermore, the density ratio (%) was calculated by dividing the measured density by the ideal calculated density obtained from the feed composition. The evaluation results are shown in Tables 13 to 16.

(Standard Deviation of Metal Elements) The target pieces were taken from 5 points of the sputtering surface of the obtained sputtering target, and the metal elements were quantified by the above-mentioned method, and the standard deviation σ of the results at the 5 points is shown in the table. For the sample part, when the center coordinates of the φ125mm surface are set to (x mm, y mm)=(0, 0), set to (x, y)=(0, 0), (-60, 0), ( +60, 0), (0, -60) and 5 parts of (0, +60). The evaluation results are shown in Tables 13 to 16.

(Specific resistance value) The sputtering surface of the obtained sputtering target was measured in the environment of 25±5° C. (20 to 30° C.) using a four-probe resistance meter LORESTA manufactured by Mitsubishi Gas Chemical. Next, the specific resistance value was measured at 5 places shown in the column of the standard deviation of the metal element, and the ratio of dividing the standard deviation by the average value is shown in the table. The evaluation results are shown in Tables 13 to 16. In addition, in the table, the specific resistance value "a×10 ^-b Ω·cm" is described as "aE-b".

(Average particle area of voids) The sample collected from the obtained sputtering target was filled with resin, then ground, and an electron probe microanalyzer (EPMA) apparatus (manufactured by JEOL Ltd.) was used to take a group image of 60 μm in length and 76 μm in width at a magnification of 1500 times. (COMPO like). For the obtained image, binarization of luminance was performed using ImageJ, an image processing software. At this time, the threshold value of brightness is set to 120. That is, only the void region with low brightness is detected. The binarization was performed, and the average particle area was determined for the obtained image using a particle measuring function. The obtained values are shown in Tables 13 to 16 as the average particle area of the pores.

(Abnormal discharge measurement) The sputtering target was sputtered at Ar 50sccm, 0.4Pa, DC615W (RPG-50 manufactured by mks), and the number of abnormal discharges during sputtering for 1 hour was measured using the power count function. The evaluation results are shown in Tables 13 to 16. Moreover, in the sputtering targets of Comparative Examples 1 to 3, abnormal discharge occurred frequently, and furthermore, the sputtering surface of the target was perforated by the abnormal discharge, so it was judged that the film formation evaluation could not be continued.

(Composition of Optical Functional Film) Using the sputtering target of the above example of the present invention, a film with a thickness of 50 nm was formed on a Si substrate under the conditions of Ar 50 sccm, 0.4 Pa, and DC 615 W. A substrate with a size of φ5 inches was used, and the substrate after film formation was cut into a size of about 20mm × 20mm centered on the coordinates of the 5 places where the target composition unevenness evaluation was performed, and 5 samples were taken from each of them. . The obtained films were subjected to quantitative analysis of Nb, W and Ti by quantitative analysis of EPMA, and the standard deviation σ of the results of 5 sheets is shown in Tables 17-20.

(Reflectivity) A 4N copper target of φ125mm×thickness t5mm was used, and one substrate was placed directly above the coordinates of the five places where the target composition unevenness evaluation was performed, totaling five substrates. The substrate was a glass substrate (EAGLE XG manufactured by Corning Corporation) having a size of 20 mm×20 mm. A Cu film with a thickness of 200 nm was formed on a glass substrate under the conditions of Ar 50sccm, 0.4Pa, and DC615W. Then, the copper target was replaced with the target of the above-mentioned example of the present invention, and the position of the glass substrate was kept unchanged, and the Cu film was formed on the Cu film under the conditions of Ar 50sccm, 0.4Pa, and DC615W with the film thicknesses described in Tables 17 to 20. The optical function film. About the film of the board|substrate of the obtained coordinate (x, y)=(0, 0) position, the reflectance of the visible light region was measured using a spectrophotometer (U-4100 by Hitachi High-Technologies). The average values of reflectance from 380 nm to 780 nm are shown in Tables 17 to 20. As the evaluation of the reflectance unevenness, the above-mentioned reflectance measurement was performed on a total of 5 pieces, and the standard deviation σ of the reflectance results of the 5 pieces is shown in the table. The standard deviation is preferably 3% or less, more preferably 2% or less, and still more preferably 1% or less.

(heat resistance) The sample whose reflectance has been measured is heated to 400°C at a rate of 10°C/sec in a nitrogen atmosphere using a lamp heating furnace, and maintained for 10 minutes. Then, it was cooled to room temperature and taken out, and the reflectance was measured in the same manner. The difference in reflectance before treatment and after treatment is described in Tables 17 to 20. The difference is preferably 10% or less, more preferably 5% or less, and still more preferably 3% or less.

(Alkali resistant) The sample whose reflectance was measured was immersed in a commercially available TMAH (Tetramethylammonium hydroxide: tetramethylammonium hydroxide) solution (2.38 wt %) at room temperature for 10 minutes, rinsed with pure water, and dried with a blower. Then, the reflectance was measured in the same manner. The difference in reflectance before treatment and after treatment is described in Tables 17 to 20. The difference is preferably 10% or less, more preferably 5% or less, and still more preferably 3% or less.

(Etching property) When the metal was Nb, the obtained film of 50 nm was immersed in a fluoronitric acid aqueous solution heated to 40°C. When the metal was Ti or W, the obtained film of 50 nm was immersed in a commercially available H ₂ O ₂ -based etching solution (GHP-3 manufactured by Kanto Chemical Co., Ltd.) heated at 40°C. In Examples 1 to 61 of the present invention, it was confirmed that all the films could be etched.

In Comparative Example 1, the average particle size of the metal Nb powder was 1.1 μm, and the sputtering target density ratio was 70.5%. Therefore, the number of abnormal discharges was large at 234 times/hour, and the optical function film could not be stably formed.

In Comparative Example 2, the average particle diameter of the zinc oxide powder was 1300 nm, and the sputtering target density ratio was 76.4%. Therefore, the number of abnormal discharges was large at 175 times/hour, and the optical function film could not be stably formed.

In Comparative Example 3, the sintering temperature was 1100° C., and the sputtering target density ratio was 78.3%. Therefore, the number of abnormal discharges was large at 142 times/hour, and the optical function film could not be stably formed.

In Comparative Example 4, since the metal Nb powder and the zinc oxide powder were dry-mixed, the standard deviation of the Nb content on the sputtered surface was large at 5.2 mass %. Therefore, in the optical function film formed into a film, the standard deviation of the Nb content is large, and the unevenness (standard deviation) of the reflectance is also large.

In Comparative Example 5, the pressing pressure during sintering was 130 MPa, and the sputtering target density ratio was 77.7%. Therefore, the number of abnormal discharges was high at 185 times/hour, and the optical function film could not be stably formed.

On the other hand, in Examples 1 to 61 of the present invention, the density ratio is 80% or more, the standard deviation of the metal element content on the sputtered surface is 5% by mass or less, and the standard deviation of the metal element content in the optical functional film formed into the film is Small, the reflectance unevenness (standard deviation) can also be suppressed to be small. In addition, the occurrence of abnormal discharge is also suppressed, and the optical function film can be stably formed.

In addition, in Examples 6 to 8, 16, 24 to 26, 37, 42 to 44, 46, and 58 of the present invention in which C was added, it was confirmed that the heat resistance of the optical functional film was further improved. In addition, in Examples 9 to 20, 27 to 38, 45 to 56, and 58 to 61 of the present invention to which the oxide of metal M was added, it was confirmed that the alkali resistance of the optical functional film was further improved.

Based on the above, it was confirmed that according to the examples of the present invention, it is possible to provide a sputtering target of an optically functional film in which the reflection of light from a metal thin film and the like can be efficiently and stably formed, excellent in heat resistance and alkali resistance, and the sputtering target can be provided. The manufacturing method and the optical function film. [Industrial Availability]

The sputtering target of this embodiment can be preferably used in the process of forming a low-reflectivity film provided in a sensing electrode (metal film) in a projection-type electrostatic capacitive touch panel or forming a black matrix of a flat panel display .

1: Substrate 11: Metal wiring film 12: Optical functional film

FIG. 1 is an explanatory cross-sectional view of a laminate film provided with an optically functional film according to an embodiment of the present invention. [Fig. 2] is a plan view of the optical function film of Fig. 1. [Fig. FIG. 3 is a schematic explanatory diagram of a sputtering target of one embodiment of the present invention, which is a flat-plate-shaped sputtering target. [ Fig. 4] Fig. 4 is a schematic explanatory view of a sputtering target in the form of a disc according to an embodiment of the present invention. 5A is a plan view of the sputtering target according to one embodiment of the present invention, which is a schematic explanatory diagram of a cylindrically-shaped sputtering target. 5B is a cross-sectional view taken along the axis of the sputtering target according to one embodiment of the present invention, which is a schematic explanatory diagram of a cylindrical-shaped sputtering target. 6 is a flowchart showing a method for producing a sputtering target according to an embodiment of the present invention.

Claims (13)

A sputtering target characterized by comprising one or more metal phases and zinc oxide phases selected from Nb, W, Ti, And the density ratio is more than 80%, The standard deviation of the individual content of the metal element consisting of one or two or more selected from Nb, W, and Ti measured at a plurality of locations on the sputtered surface was 5 mass % or less. The sputtering target of claim 1, wherein the average particle area of the pores is 5 μm ² or less. The sputtering target according to claim 1 or 2, which comprises oxides of one or more metals M selected from Al, Si, Ga, In, Sn, Ti, Nb, Zr, Mo, Ta, W, Y , the total content of the metal M is in the range of 0.1 mass % or more and 40 mass % or less, when all metal elements are taken as 100 mass %. The sputtering target according to any one of claims 1 to 3, wherein the ratio of the standard deviation of the specific resistance values measured at a plurality of locations on the sputtering surface divided by the average value is 100% or less. The sputtering target according to any one of claims 1 to 4, wherein the total content of Nb, W, and Ti is 50 mass % or more with respect to the whole including O and C. The sputtering target according to any one of claims 1 to 5, further comprising C in a range of 1 mass % or more and 10 mass % or less with respect to the whole. A method for manufacturing a sputtering target, which is characterized by a method for manufacturing a sputtering target comprising one or more metal phases selected from Nb, W, and Ti and a zinc oxide phase, comprising: Mix metal powder with an average particle size of 5 μm or more selected from one or more of Nb, W, Ti and zinc oxide powder with an average particle size of 1 μm or less using a solvent with a water concentration of 30 vol% or more and drying the granulated powder to obtain a granulated powder production step, and The sintering step of heating and pressing the obtained granulated powder at a temperature of 1000°C or less and a pressure of 145MPa or more and sintering. The method for producing a sputtering target according to claim 7, wherein before the sintering step, a forming step of pressurizing the granulated powder at normal temperature to form the target is provided. The method for producing a sputtering target according to claim 7 or 8, wherein in the step of producing the granulated powder, in addition to the metal powder and the zinc oxide powder, a mixture of self-made materials having an average particle size of 0.1 μm or more and 12 μm or less is mixed. Al, Si, Ga, In, Sn, Ti, Nb, Zr, Mo, Ta, W, Y selected one or more metal M oxide powder. The method for producing a sputtering target according to any one of claims 7 to 9, wherein the average particle size of the zinc oxide powder is 100 nm or less. The method for producing a sputtering target according to any one of claims 7 to 10, wherein the average particle size of the metal powder is 10 μm or more. An optical function film, which is characterized by comprising an optical function film composed of one or more metals selected from Nb, W, Ti and zinc oxide, And the standard deviation of the individual content of the metal element which consists of 1 type or 2 or more types selected from Nb, W, and Ti is 5 mass % or less. The optical function film according to claim 12, comprising oxides of one or more metals M selected from Al, Si, Ga, In, Sn, Ti, Nb, Zr, Mo, Ta, W, and Y.

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