JP2016160448A - Sputtering target and optical functional film for reducing metal reflection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film (as will be called an optical function film) which is formed so as to be adjacent to the wiring of a metal film in a touch panel, thereby to reduce the metallic sheen of the wiring pattern of a touch panel screen, and to provide a sputtering target for sputtering and forming the optical function film.SOLUTION: A sputtering target is made of a metal alloy containing 85 to 95 mass % of the total of one kind or two kinds of one of Cu and Fe and 5 to 15 mass% of the total of one kind or two kinds of Ni and Mn. An optical functional film is made of an oxide sputtered and filmed in an oxidizing atmosphere by using said target and has an average reflectance of 30% or less.SELECTED DRAWING: None

Description

  The present invention relates to a sputtering target for sputtering an optical functional film which is laminated on a metal thin film and reduces metal reflection.

  In recent years, a projected capacitive touch panel has been used as an input means for portable terminal devices and the like. In this touch panel, when a finger approaches a sensing electrode arranged on the touch panel substrate, a capacitance is formed between the fingertip and the electrode. In this type of touch panel, the touch position is detected by a control circuit or the like based on the change in capacitance. In order to detect a touch position, an electrode for sensing is required, and this electrode is formed by patterning. An X electrode extending in the X direction and a Y electrode extending in the Y direction are formed on one surface of the transparent substrate. And a technique of arranging them in a grid pattern is known (see, for example, Patent Document 1).

  In addition, in a flat panel display typified by a liquid crystal display device or a plasma display, a color filter for the purpose of color display is employed. In this color filter, red (R), green (G), and blue (B) micro color filters are formed in a matrix corresponding to each pixel, and the contrast and color are between these micro color filters. A black member called a black matrix (hereinafter referred to as BM) is formed for the purpose of improving the purity and improving the visibility.

  For this BM, chromium (Cr) or a chromium compound is used, a light-shielding film made of a metal chromium single layer film, a laminated film of metal chromium and chromium oxide, or Cr metal, Cr oxide and Cr nitride. It has been proposed to form a low reflection film such as a laminated film (for example, see Patent Document 2). Further, forming a light-shielding film made of an alloy of nickel (Ni) and vanadium (V), or an oxide, nitride or oxynitride of Ni and V (see, for example, Patent Document 3) It has also been proposed to form a tungsten nitride (W) film as a light-shielding film (see, for example, Patent Document 4).

  On the other hand, in the solar cell panel, when sunlight enters through a glass substrate or the like, the back electrode of the solar cell is formed on the opposite side. As the back electrode, a metal film made of molybdenum (Mo), silver (Ag), or the like is used. When such a solar cell panel is viewed from the back side, if the metal film that is the back electrode is visible as it is, it has a metallic luster, so it does not look good as a product. Therefore, the metallic luster is usually hidden by pasting a black back sheet or the like to protect the back electrode.

JP 2013-235354 A JP 2002-182190 A JP 2001-234267 A JP 2013-077942 A

  An ITO thin film has been used as an electrode for detecting the touch position on a conventional touch panel. However, with the increase in the area of the touch panel, the use of an ITO thin film increases the resistance and the detection accuracy. There was also a problem of lowering. In recent years, therefore, it has been proposed to use a low-resistance metal thin film as the metal wiring instead of the ITO thin film. However, since the metal wiring using this metal thin film reflects external light, the metallic luster of the wiring pattern is visible from the outside of the panel, which makes it difficult to use the touch panel.

  Therefore, the present invention forms a film adjacent to the wiring of the metal film in the touch panel to reduce the metallic luster of the wiring pattern of the touch panel screen (hereinafter referred to as an optical function film), and this optical function film. It is an object to provide a sputtering target for sputtering film formation.

The inventors focused on the fact that Cu oxide films, Fe oxide films, and the like have light absorption characteristics with respect to external light in the visible light region, in other words, the appearance is black. That is, it was found that the metallic luster of the wiring pattern of the touch panel screen can be reduced by forming the Cu or Fe oxide film adjacent to the wiring of the metal film.
By the way, as long as this oxide film is formed on the wiring of the touch panel, if productivity is considered, the wiring pattern is formed after the oxide film is formed on the surface of the metal film formed on the touch panel substrate. It is efficient to form. In this wiring patterning, the metal film and the oxide film are usually etched by an etchant through a pattern mask. Here, the oxide film of Cu or Fe is excellent in etching property with respect to an etching solution, and is also excellent in reliability (chemical resistance and weather resistance). Note that the above-mentioned etching property means that the metal film and the oxide film are etched in alignment, and it is preferable that there is no problem in patterning such as etching rate and over-etching.

However, it has been found that when a simple Cu or Fe oxide film is used, reflection on external light occurs on its own surface. This is not preferable in reducing the metallic luster of the wiring pattern.
Therefore, the knowledge that it is effective to add Ni and Mn to reduce the reflection characteristics of the oxide film of Cu or Fe was obtained. Therefore, the alloy components of the sputtering target used for sputtering of the optical functional film. As described above, when any one or two of Ni and Mn is added to any one or two of Cu and Fe and this optical functional film is formed by sputtering, either one of Cu and Fe or An optical functional film made of an oxide containing two types and one or two of Ni and Mn is obtained, and this optical functional film satisfies all the conditions of etching property, reliability, and reflection characteristics. It is suitable for reducing the metallic luster of the wiring pattern of the touch panel screen.

Therefore, the present invention has been obtained from the above findings, and the following configuration has been adopted in order to solve the above problems.
(1) The sputtering target of the present invention contains 85 to 95 mass% in total of any one or two of Cu and Fe as metal elements, and is a total of any one or two of Ni and Mn. It consists of a metal alloy containing 5 to 15% by mass.
(2) The optical functional film of the present invention contains 85 to 95 mass% in total of any one or two of Cu and Fe as metal elements, and is a total of any one or two of Ni and Mn. It consists of an oxide containing 5 to 15% by mass.
(3) The optical functional film of the present invention is an optical functional film made of an oxide formed by sputtering adjacent to a metal film using the sputtering target of (1), from the optical functional film side. The measured average reflectance is 30% or less.

  As described above, the sputtering target of the present invention contains 85 to 95 mass% in total of any one or two of Cu and Fe, and 5 in total in any one or two of Ni and Mn. It is characterized by comprising a metal alloy containing ˜15% by mass, and an optical functional film excellent in etching property, reflection property and reliability can be formed by sputtering.

  The optical functional film formed by sputtering using the above-described sputtering target of the present invention contains 85 to 95 mass% in total of any one or two of Cu and Fe, and any one of Ni and Mn. It consists of an oxide containing 5 to 15% by mass in total of seeds or two kinds. Here, when the film is formed by sputtering, the composition ratio of the metal component of the optical functional film is substantially the same as the composition ratio of the metal component of the sputtering target. When sputtering film formation is performed using the sputtering target of the present invention, sputtering is performed by adding oxygen to a rare gas such as argon.

  Next, application examples of the optical functional film of the present invention will be described. In the case of the solar cell panel described above, the optical functional film of the present invention is applied to protect the back electrode of the solar cell and hide its metallic luster, so that the glass substrate / back electrode (metal film) / The optical functional film has a laminated structure, and the optical functional film is disposed adjacent to the metal film. Further, in the case of the touch panel described above, the sensing electrodes are formed by patterning on the transparent substrate, and are arranged in a grid pattern on one surface of the transparent substrate. When the optical functional film of the present invention is applied to this touch panel, a laminated structure of transparent substrate / optical functional film / electrode (metal film) is formed, and the optical functional film is disposed adjacent to the metal film. Furthermore, in the case of a film with wiring, etc., it has a laminated structure of a transparent substrate (film) / optical function film / wiring (metal film) / optical function film, and the optical function film is provided adjacent to the metal film. It is done.

  In addition, although the sputtering target for optical function film formation of this invention was comprised with the metal alloy by melt casting, it is good also as a metal alloy target by hot press, and contains each metal element in the optical function film of this invention When the optical functional film of the present invention is formed by sputtering using this oxide sputtering target, sputtering is preferably performed with a rare gas such as argon.

  As described above, the sputtering target according to the present invention includes any one or two of Cu and Fe: 85 to 95% by mass, and one or two of Ni and Mn: 5 to 15% by mass. Since it consists of the contained metal, when this sputtering target is used for sputtering film formation, an optical functional film satisfying all of etching property, concealing property (reducing metallic luster of the wiring pattern) and reliability can be obtained. Therefore, the appearance of the touch screen attached to the touch panel is improved, and the touch panel productivity is improved. Furthermore, the optical functional film of the present invention can also be used as a black member of a black matrix (BM) in a flat panel display, and can be provided in place of a black back sheet that also serves as protection of the back electrode of the solar cell panel. Yes, it is suitable for hiding their metallic luster.

  Next, the sputtering target for forming an optical functional film of the present invention and the optical functional film formed thereon will be specifically described below with reference to examples.

〔Example〕
First, in order to produce a sputtering target for forming an optical functional film, granular Cu, Fe, Ni, and Mn are weighed so as to have the target composition ratios shown in Tables 1 and 2, and each weighed is measured. The raw material was put into a graphite crucible, heated and dissolved in a vacuum to 1300 ° C. in a high-frequency heating furnace, and put into a graphite mold of a predetermined size. Thereafter, the mixture was allowed to cool and cooled to room temperature, and metal alloy castings of Examples 1 to 48 were produced. The metal alloy castings of Examples 1 to 48 were machined into a predetermined shape, and a backing plate was attached to produce the sputtering targets of Examples 1 to 48.

[Comparative Example]
In order to compare with the said Example, it carried out similarly to the case of the Example, and produced the sputtering target of Comparative Examples 1-19 which has the target composition ratio shown in Table 3. In the case of Comparative Examples 1 to 19, the content of any of the metal elements is out of the range in the case of the examples.

  Next, about the sputtering target of the Example manufactured above and the comparative example, the result of having analyzed the metal component composition by ICP was shown to Tables 1-3.

The results of analyzing the metal component composition by ICP for the optical functional films formed by sputtering using the oxide sputtering targets of Examples 1 to 48 and Comparative Examples 1 to 19 are shown in Tables 4 to 6. In addition, it was confirmed with an electron beam microanalyzer (EPMA) that the film was an oxide.
<Film formation>
Using the sputtering targets of the above examples and comparative examples, sputtering film formation was performed under the following film formation conditions.
・ Power supply: DC power supply ・ Power: 600 W (Ag film only, 200 W)
・ Gas pressure: 0.2Pa
-Gas flow rate: In the case of an optical functional film Ar: 34 sccm O ₂ : 16 sccm
In the case of Cu, Al, Ag, Mo film Ar: 50 sccm
-TS distance: 70mm
・ Substrate: Glass substrate (Eagle XG)
-Substrate temperature: Room temperature-Substrate size: 20mm square-Thickness: 50nm

  Furthermore, about the optical function film (laminated film) laminated | stacked by sputtering film-forming on the metal film using the sputtering target of Examples 1-48 and Comparative Examples 1-19, before and after an average reflectance and a constant temperature / humidity test The maximum value of reflectance change was measured.

<Measurement of reflectance>
Sputtering film formation was performed under the same film formation conditions as described above. Note that an oxide film (optical functional film) having a thickness of 50 nm and a film of copper, aluminum, silver, or molybdenum having a thickness of 200 nm were stacked in this order on a glass substrate (Eagle XG). In Example 46, Al was used, in Example 47 Ag was used, in Example 48 Mo was used, and in other examples and comparative examples, Cu was used to form a metal film. . The metal film is for metal wiring, and each metal sputtering target was used for the film formation. In addition, the metal used for this metal film was shown in the "Used metal film" column of Tables 4-6.

  Next, the reflectance was measured about the laminated film formed on the glass substrate as mentioned above. In this measurement, a spectrophotometer (Hitachi U4100) was used, and measurement was performed at a wavelength of 400 to 800 nm from the glass substrate side. And it measured by 4 samples produced similarly, averaged the obtained measured value, and calculated | required the average reflectance. The measurement results are shown in the “average reflectance (%)” column of Tables 4-6.

<Measurement of reflectance change before and after test>
Furthermore, a constant temperature and humidity test was performed on the laminated film formed on the glass substrate as described above under the test conditions shown below.
・ Temperature: 85 ℃
・ Humidity: 85%
・ Retention time: 250 hours

  After this constant temperature and humidity test, the reflectance within the above wavelength range was measured by the method described above. Therefore, the difference in reflectance at each wavelength of 400, 500, 600, 700, and 800 nm before and after the test was determined, and the absolute value was defined as the change in reflectance. The maximum value of the reflectance change among the above five wavelengths is shown in the “maximum reflectance change value (%)” column of Tables 4-6.

<Measurement of etching rate>
An etching test was performed on the optical functional film of 50 nm formed on the glass substrate under the etching conditions shown below in the same manner as in the reflectance measurement. In the etching test, the time until the optical functional film was completely melted was measured, and the etching rate was calculated. The results are shown in the “etching rate (nm / sec)” column of Tables 4-6.
・ Method: Dip method ・ Etching solution: SEA2 (manufactured by Kanto Chemical Co., Inc.)
・ Liquid temperature: 40 ℃

According to the above result, in any of the sputtering targets of Examples 1 to 48, any one or two of Cu and Fe: 85 to 95% by mass, and any one or two of Ni and Mn. : All the laminated films formed by sputtering using these sputtering targets exhibit an average reflectance of 30% or less, and the external light generated by the film itself is contained. It was found that the metallic luster of the wiring pattern due to reflection can be reduced. Further, it was confirmed that the reflectance change before and after the constant temperature and humidity test was small and reliable. Furthermore, it is confirmed that the etching rate for the optical functional film is about the same as that of the laminated metal film, and simultaneously patterning the laminated optical functional film and the metal film, It turned out that there is no problem in etching.
Therefore, it was confirmed that the optical functional film formed by sputtering using the sputtering targets of Examples 1 to 48 has both concealability (reduction of metallic luster of the wiring pattern) and reliability.

  On the other hand, all the optical functional films formed by sputtering using the sputtering targets of Comparative Examples 1 to 3, 8 to 10, and 14 to 16 have a Ni and Mn content lower than 5 mass%, and an average reflectance. Is over 30%, the film itself has gloss and is inferior in hiding properties. Since the optical functional films formed by sputtering using the sputtering targets of Comparative Examples 4 to 7, 11 to 13, and 17 to 19 all have Ni and Mn contents exceeding 15% by mass, the etching rate is extremely high. Slow and inferior in etchability.

  As mentioned above, 85-95 mass% was contained in the total of any 1 type or 2 types of Cu and Fe, and 5-15 mass% was contained in the total of any 1 type or 2 types of Ni and Mn. The optical functional film of metal alloy oxide formed by sputtering oxygen using a metal alloy sputtering target satisfies all of etching, hiding (reducing the metallic luster of the wiring pattern), and reliability. It was confirmed that

In order to use the present invention as a sputtering target, the surface roughness is 5.0 μm or less, more preferably 1.0 μm or less, the particle size is 20 μm or less, more preferably 10 μm or less, and the metal impurity concentration is 0.00. 1 atomic% or less, more preferably 0.05 atomic% or less, bending strength: 50 MPa or more, more preferably 100 MPa or more.
The technical scope of the present invention is not limited to the above-described embodiment and examples, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment and the above examples, the target is manufactured by melt casting. However, as another method, a hot press method, a HIP method (hot isostatic pressing method), or the like may be adopted. I do not care.
Moreover, you may employ | adopt metals, films, etc. other than glass as a base material.

Claims (3)

  Metal alloy containing 85 to 95 mass% in total of any one or two of Cu and Fe as metal elements, and 5 to 15 mass% in total of any one or two of Ni and Mn A sputtering target comprising:   Oxide containing 85 to 95 mass% in total of any one or two of Cu and Fe as metal elements, and 5 to 15 mass% in total of any one or two of Ni and Mn An optical functional film comprising: An optical functional film comprising an oxide formed by sputtering adjacent to a metal film using the sputtering target according to claim 1,
An optical functional film, wherein an average reflectance measured from the optical functional film side is 30% or less.