TW201710522A - Sputtering target material, method of producing the same, and optical functional film - Google Patents

Abstract

A sputtering target material, which includes Fe and Mo as metal elements; a part or all of the metal elements are in an oxide form; and Fe-Mo-O system compound is included in an oxide phase, is provided.

Description

Sputtering target, manufacturing method thereof and optical functional film

The present invention relates to a sputtering target for an optical functional film which is deposited on a metal thin film by sputtering and which is reduced in reflection of metal, and a method for producing the sputtering target, and further relates to a sputtering target An optical functional film formed by sputtering.

In recent years, as an input means for a portable terminal device or the like, a projection type capacitive touch panel is being used. In the touch panel of this aspect, if the finger approaches the sensing electrode disposed on the substrate of the touch panel, an electrostatic capacitance is formed between the fingertip and the electrode, and the touch is detected by the control circuit or the like based on the change in capacitance thereof. position. In order to detect the touch position, an electrode for sensing is necessary, and the electrode for sensing is usually formed by patterning, for example, generally, an X electrode extending in the X direction on one surface of the transparent substrate and extending in the Y direction The Y electrodes are arranged in a matrix form (for example, refer to Patent Document 1).

On the other hand, the liquid crystal display device or the plasma display device is A representative flat panel display uses a color filter for the purpose of color display. The color filter system and the red (R), green (G), and blue (B) micro color filters are formed in a matrix shape corresponding to each pixel, and the micro color filters are based on each other. A black member called a black matrix is formed for the purpose of improving contrast or color purity and improving field of view.

As the black matrix (hereinafter referred to as "BM"), it is proposed to use a chromium (Cr) or chromium compound to form a light-shielding film made of a metal chromium single-layer film, or a laminated film of metal chromium and chromium oxide, or a Cr metal. A low-reflection film such as a laminate film of a Cr oxide or a Cr nitride (for example, refer to Patent Document 2).

Further, a light-shielding film formed of an alloy of nickel (Ni) and vanadium (V) or an oxide of Ni and V, a nitride or an oxynitride (for example, refer to Patent Document 3) or nitriding is also proposed. A tungsten (W) film is used as a light shielding film (for example, refer to Patent Document 4).

On the other hand, in the solar cell panel, when sunlight is incident on a glass substrate or the like, the back surface electrode of the solar cell is formed on the opposite side. As the back surface electrode, a metal film such as molybdenum (Mo) or silver (Ag) is used. When the solar cell panel of such a state is viewed from the back side, since the metal film of the back electrode is directly seen, it exhibits metallic luster, and thus the appearance of the product is poor. Therefore, a black backing sheet or the like which is protected by the back electrode is usually attached, and the metallic luster is concealed.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Laid-Open Patent Publication No. 2013-235354 (A)

[Patent Document 2] Japanese Laid-Open Patent Publication No. 2002-182190 (A)

[Patent Document 3] Japanese Laid-Open Patent Publication No. 2001-234267 (A)

[Patent Document 4] Japanese Laid-Open Patent Publication No. 2013-079432 (A)

In the conventional touch panel, an ITO film is used for the electrode for detecting the touch position. However, when the ITO film is used, the resistance of the ITO film is increased and the detection accuracy is also lowered. Therefore, in recent years, instead of the ITO film, a metal film using a low resistance has been proposed as a metal wiring. However, the metal wiring using such a metal thin film reflects external light due to display of high reflection characteristics, so that the metallic luster of the wiring pattern is seen from the outside of the panel, and there is a problem that it is difficult to use the touch panel.

Therefore, the present inventors have developed a film in which the metallic luster of the wiring pattern of the touch panel screen can be reduced by sputtering film formation on the wiring of the metal thin film of the touch panel (hereinafter referred to as "optical functional film"). In order to develop an optimum sputtering target by sputtering a film of such an optical functional film, an active experiment and research were repeated.

In the process, attention is paid to light absorption characteristics of external light having a light-visible region due to Mo oxide or In oxide, in other words, since the reflectance is extremely low, the appearance is black. That is, it is recognized that an oxide film formed of an oxide of Mo is formed on a wiring of a metal thin film or by Mo The oxide film formed of the oxide of the oxide and the oxide of In serves as an optical functional film, which can reduce the metallic luster of the wiring pattern.

Further, an oxide film made of an oxide of Mo or an oxide film made of an oxide of Mo and an oxide of In is used as described below, and there is a lack of reliability at or after etching ( In order to solve this problem, the problem of chemical resistance and weather resistance is improved, and it has been found that it is effective to add an oxide of Fe first.

In other words, when the oxide film is formed on the wiring of the touch panel as the optical function film, the oxide film is formed on the surface of the metal film formed on the touch panel substrate in consideration of productivity. It is preferable to form a wiring pattern. When the wiring pattern is formed, the metal thin film and the oxide film are usually etched by the etching liquid after the pattern mask is formed. In the etching by such a pattern, the oxide of Mo or the oxide of In is excellent in etching property of the etching liquid, but conversely, reliability (chemical resistance, weather resistance) is poor. Further, the above-mentioned etching property is such that the metal thin film and the oxide film are integrated and etched, so that the etching rate, over-etching, and the like are preferably not hindered from patterning.

On the other hand, it has been found that when Fe is formed by an oxide film made of an oxide of Mo or an oxide film made of an oxide of Mo and an oxide of In, it is effective to add Fe. In other words, it has been recognized that an optical functional film containing not only an oxide of Mo and an oxide of In but also an oxide of Fe can reduce the metallic luster of the wiring pattern and improve the reliability as described above.

Therefore, in order to form such an optical functional film on a metal film, it is found that an oxide of Mo, or an oxide of Mo and oxygen of In is used. The sputtering target in which the oxide of the compound and Fe is mainly used is effective by a sputtering film formation system. In other words, it is recognized that when a sputtering target mainly composed of an oxide of Mo, an oxide of Mo, an oxide of Mo, and an oxide of Fe is used as a sputtering target, Mo is obtained as described above. An optical functional film having a low reflectance and high reliability, mainly composed of an oxide, an oxide of Mo, an oxide of In, and an oxide of Fe.

The optical functional film thus obtained can also be used as a black member of a black matrix (BM) in a flat panel display, and can also protect the back electrode of the solar cell panel and be provided instead of the black backing sheet. Goodly conceal the metallic luster of these.

However, in order to put the optical functional film as described above into practical use, after further conducting an experimental study on a sputtering target for optical film formation by sputtering, it is known that the oxide of Mo and the oxide of Fe are simply used. The sputter target of the tissue in which it is mixed with (or further In oxide) is susceptible to cracking. That is, when it is determined that the target material in which the oxide phase is mixed is used, it is preferred to use the oxide powder as a raw material, and the mixed powder is equal to high temperature sintering by hot pressurization, but the cooling process after high sintering thereof. In the case where the sintered body of the target is cracked and the target is heated at the time of sputtering, there is also a problem that the target is cracked. When cracks occur during the production of the target or during sputtering using the target, the yield is lowered and the productivity is hindered.

The present invention is based on the above circumstances, and the basic object thereof is to provide a sputtering target which is not only capable of forming a low reflectance but also is excellent for shielding a metallic luster and having excellent reliability if it is sputtered on a metal thin film. Functional film, and therefore as a sputtering target material itself is not prone to cracking, Further, a method of manufacturing such an excellent sputtering target is provided, and an optical functional film in which the target is used for a sputtering target by sputtering to form a film is provided.

In order to solve the problem that the sputtering target of the structure in which the oxide of Mo or the oxide of Mo and the oxide of Mo and the oxide of Fe are mixed is likely to be cracked as described above, it is presumed that the above-mentioned The main cause of the cracking of the sputtering target of the structure is that the difference in thermal expansion coefficient (the difference in linear expansion coefficient) between the oxide of Mo and the oxide of Fe is large.

That is, the linear expansion coefficient with respect to Mo oxide is about 4×10 ^-6 /K, and the linear expansion coefficient of Fe oxide is about 10×10 ^-6 /K, and the difference is large, so it is presumed that Mo is mixed. The phase of the oxide phase and the phase of the Fe oxide are present in the sputtering target of the structure. When the temperature changes, the expansion and contraction become uneven, and a large thermal stress occurs inside, which is prone to cracking.

Therefore, after further research, it was found that not only the phase of Mo oxide (or Mo oxide and In oxide) but also the phase of Fe oxide was mixed, and it was assumed to contain Mo and Fe and O (oxygen) (or Further, the phase of the compound of In), that is, the structure of the phase formed by the composite oxide of Mo, Fe, or (In), can suppress the occurrence of cracks, and thus the present invention has been completed.

Therefore, the sputtering target of the basic state (first aspect) of the present invention is characterized in that Fe and Mo are contained as a metal element, and part or all of the metal element is present in the form of an oxide, and the oxide phase Contains Fe-Mo-O based compounds.

Further, the Fe-Mo-O-based compound described above may be referred to as a Fe-Mo-based composite oxide, and is also simply referred to as a composite oxide hereinafter.

Further, the sputtering target of the second aspect is the sputtering target of the first aspect described above, wherein among all the metal components, the content of the metal element as Fe is 20 to 95 at%, and the content of the metal element as Mo is 5 to 5. 80at%.

Further, the sputtering target of the third aspect is the sputtering target of the first aspect or the second aspect described above, and further contains In as a metal element.

Further, the sputtering target of the fourth aspect is the sputtering target of the third aspect described above, and among all the metal components, the content of the metal element as In is 0.1 to 23 at%.

Further, the sputtering target of the fifth aspect is the sputtering target according to any one of the first to fourth aspects, wherein the Fe-Mo-O compound is mainly composed of a Fe ₂ Mo ₃ O ₈ phase.

The sputtering target of the sixth aspect is the sputtering target of the fifth aspect described above, wherein the diffraction peak intensity of the (002) plane of the Fe ₂ Mo ₃ O ₈ phase is (011) of the MoO ₂ phase. 1.5% or more of the diffraction peak intensity of the surface, or 1.5% or more of the diffraction peak intensity of the (311) plane of the Fe ₃ O ₄ phase, and 300 of the diffraction peak intensity of the (011) plane of the MoO ₂ phase % or less, and is 300% or less of the diffraction peak intensity of the (311) plane of the Fe ₃ O ₄ phase.

Further, the seventh aspect is a method for producing a sputtering target according to any one of the first to sixth aspects described above.

That is, the method for producing a sputtering target of the seventh aspect is characterized in that a mixed powder of Fe oxide powder and Mo oxide powder or Fe is oxidized. The powder of the powder and the mixed powder of the Mo oxide powder and the In oxide powder are sintered in the range of 840 to 950 °C.

Further, the eighth aspect defines an optical functional film.

That is, the optical functional film of the eighth aspect is characterized in that a sputtering target of any one of the first to sixth aspects is used in the target, and an oxide adjacent to the metal thin film and formed by sputtering is formed. In the optical functional film, the average optical reflectance of the optical functional film measured from the side not adjacent to the metal film is 30% or less.

According to the sputtering target of the present invention, crack formation can be effectively suppressed at the time of production or when sputtering using the film, thereby improving yield and improving productivity. Further, the sputtering target containing In as a metal component can effectively suppress the occurrence of warpage, so that the yield and productivity can be further improved.

1‧‧‧Mo oxide phase region

2‧‧‧Fe oxide phase region

3‧‧‧Fe-Mo composite oxide phase (Fe-Mo-O compound phase)

Fig. 1 is a schematic view showing an example of a cross-sectional structure of a sputtering target of the present invention.

Fig. 2 is a view showing an example of a cross-sectional structure of a sputtering target of the comparative material of the present invention.

Fig. 3 is a flow chart showing an example of the results of XRD measurement of the sputtering target of the present invention.

Fig. 4 is a flow chart showing another example of the results of XRD measurement of the sputtering target of the present invention.

Fig. 5 is a flow chart showing an example of the results of XRD measurement of the sputtering target of the comparative material of the present invention.

In the following, the sputtering target of the present invention (hereinafter referred to as "the sputtering target of the present invention"), the method for producing the same (hereinafter referred to as "the method for producing the sputtering target of the present invention"), and the use of the present invention The optical functional film (hereinafter referred to as "the optical functional film of the present invention") in which the sputtering target is sputter-deposited will be described in more detail.

[Splating target]

The sputtering target of the present invention basically contains Fe and Mo as metal elements, and some or all of the foregoing metal elements exist in the form of oxides, and the oxide phase contains Fe-Mo-O compounds (Fe-Mo). Those who are complex oxides.

Here, an oxide of Fe alone (typically Fe ₃ O ₄ ) and an oxide of Mo alone (typically MoO ₂ ) are also present in the target, but further contain a Fe-Mo composite oxide. (Representatively, Fe ₂ Mo ₃ O ₈ or a part of FeMoO ₄ ) can suppress the occurrence of cracks.

The total amount of all the metal elements contained in the sputtering target of the present invention is 34 atom% to 43 atom%. This value can be obtained by measuring the sputter target produced as a sample by ICP.

The effect of suppressing cracking by the presence of such a Fe-Mo-based composite oxide can be found by experiments by the inventors of the present invention, but it is considered that the effect of preventing cracking due to the presence of the Fe-Mo-based composite oxide is considered to be For the following reasons.

That is, the Fe-Mo composite oxide has a linear expansion coefficient of about 7×10 ^-6 /K, which is a linear expansion coefficient value between the linear expansion coefficient of the oxide of Fe alone and the linear expansion coefficient of the oxide of Mo alone. . In the Fe-Mo composite oxide phase, when the mixed oxide powder of the Fe oxide powder and the Mo oxide powder is sintered at a high temperature of, for example, about 840 ° C or higher, the target is usually deposited in Fe alone. The oxide is formed in a manner between the oxide of Mo alone. Therefore, the Fe-Mo composite oxide is considered to have a function as a buffer material between the oxide of Fe alone and the oxide of Mo alone, and is effective for occurrence of cracks.

Further, the Fe-Mo composite oxide formed between the Fe oxide and the Mo oxide by the high-temperature sintering method as described above is Fe and Mo between the Fe oxide powder particles and the Mo oxide powder particles which are in contact with each other. And O is generated as a result of mutual diffusion (solid diffusion), so that the adjacent Fe oxide phase and the Fe-Mo composite oxide phase in the obtained target (sintered body), and the adjacent Mo oxide phase and Fe- The Mo-based composite oxide phases are strongly bonded due to solid phase diffusion.

Therefore, it is presumed that the above two effects are complementary, and cracking is unlikely to occur when the temperature changes.

Here, when the target is produced by sintering at a high temperature of about 840 ° C or higher as described above, the Fe-Mo composite oxide phase in the target (sintered body) The (Fe-Mo-O-based compound phase) is present between the oxide of Fe alone and the oxide of Mo alone by the inventors of the present invention. As an example, FIG. 1 schematically shows the cross-sectional structure of a target (sintered body) obtained by sintering at 880 ° C in Example 2 to be described later. In Fig. 1, the region 1 with a slanted line is a region having a high Mo concentration and no Fe, and is identified as a region of the Mo oxide phase, and a region 2 with a high concentration of Fe and a region containing no Mo is identified as Fe. In the region of the oxide phase, the blank region 3 is determined as a region containing a Fe-Mo composite oxide phase (Fe-Mo-O compound phase) in which Mo and Fe are present and the Mo concentration and the Fe concentration are intermediate. From FIG. 1, it is understood that an Fe-Mo-based composite oxide phase (Fe-Mo-O-based compound phase) 3 exists between the Mo oxide phase region 1 and the Fe oxide phase region 2.

Further, for comparison, the cross-sectional structure of the target (sintered body) obtained by sintering at 700 ° C in Comparative Example 1 to be described later is schematically shown in Fig. 2 . It can be seen from Fig. 2 that the slanted Mo oxide phase 1 is almost directly adjacent to the dotted Fe oxide phase region 2, and substantially no Fe-Mo composite oxide phase (Fe-Mo-O compound phase) .

Further, the presence of the Fe-Mo-O-based compound (Fe-Mo-based composite oxide) in the sputtering target can be confirmed by XRD (X-ray diffraction), and the Fe-Mo-O-based compound (Fe-Mo system) The ratio of the presence of the composite oxide (relative to the amount of the oxide of Fe alone and the oxide of Mo alone) can also be determined by XRD, but this point is re-described in the following description with respect to the preferred range of the above-mentioned existence ratio. .

It is desirable in the sputtering target of the present invention that all the metal components are The proportion of Fe (as a content of a metal element) is in the range of 20 to 95 at%, and the proportion of Mo (as a content of a metal element) is 5 to 80 at%. In other words, in the sputtering target of the present invention, all or a part of Fe and Mo are present in the form of oxides (separate oxides and composite oxides), but include Fe and Mo in the oxides as all metals. The ratio of the components is expected to be 20 to 95 at% of Fe and 5 to 80 at% of Mo.

When an optical functional film is obtained by sputtering using a sputtering-based sputtering target to form an optical functional film, the composition of the optical functional film is substantially the same as that of the sputtering target. Therefore, the composition of the sputtering target can be selected as long as it satisfies the characteristics required for the optical functional film. Based on these viewpoints, the desired composition of the sputtering target is as a Fe metal element with respect to all the metal components. The content ratio of the metal element is in the range of 20 to 95 at%, and the content ratio of the metal element of Mo is 5 to 80 at%.

When the Mo content of all the metal components is less than 5 at%, the average reflectance is not 30% or less in the wavelength of 400 to 800 nm in the visible light, and the metallic luster of the wiring pattern cannot be suppressed by the reflection of the laminated film. Therefore, it cannot be an optical functional film which is the ultimate object of the present invention.

On the other hand, when Mo in all the metal components exceeds 80 at%, the maximum value of the change in reflectance before and after the constant temperature and humidity test is 15% or more, so that the reflectance change before and after the constant temperature and humidity test is suppressed, and the reflectance characteristics are improved. Reliability, so Mo is preferably set to 80 at% or less. In addition, when Mo exceeds 60%, the maximum value of the change in reflectance is 10 at% or more, and when Mo exceeds 50 at%, the maximum value of the change in reflectance is 5% or more. Therefore, the ratio of Mo is increased as the reflectance of the optical functional film. The lower the reliability of sex, the better. However, if Mo is small, since the average value of the reflectance becomes large, it is desirable that Mo is in the range of 5 to 80 at%, particularly 25 to 60 at%, based on the combination.

When the proportion of Fe in all the metal components is less than 20 at%, the maximum value of the reflectance change before and after the constant temperature and humidity test is 15% or more in the wavelength of 400 to 800 nm in visible light, and the reflectance of the optical functional film is The reliability of the features is reduced. When the amount of Fe is more than 95 at%, the reflectance is not 30% or less in the wavelength of 400 to 800 nm in the visible light, and the metallic luster of the wiring pattern cannot be suppressed by the reflection of the optical functional film (laminated film), and the object of the present invention cannot be achieved. Optical functional films are not good. Further, the ratio of Fe is preferably in the range of 20 to 95 at%, particularly in the range of 40 to 75 at%.

Further, in the sputtering target of the present invention, In may be contained as a metal component as needed. In other words, when the Fe-Mo composite oxide phase as described above is formed in the target, it is confirmed that warpage tends to occur as a thin plate. However, by adding In as a metal element (actually added as an oxide of In), it was found that warpage can be suppressed.

Here, in general sputtering, a thin plate made of a target is generally subjected to sputtering by solder or the like on the surface of a backing plate made of Cu or the like. In this case, if the warpage of the target sheet is large, it is difficult to uniformly follow the backing sheet, and there is a hindrance to the subsequent automatic processing, thereby impairing the productivity, and suppressing by adding In can be suppressed. Warping can avoid these problems. Further, In is mainly contained in the form of In ₂ O ₃ in the target, and may be contained in the form of a composite oxide in the same manner as Mo or Fe. The composite oxide containing In is exemplified by, for example, an Fe-Mo-In composite oxide (Fe-Mo-In-O compound) or an Fe-In composite oxide (Fe-In-O compound) or Mo. -In composite oxide (such as a Mo-In-O compound).

When the content of In is actively contained as described above, the content of In as the metal component is preferably in the range of 0.1 to 23 at% in terms of the ratio of all the metal components. When the In composition is less than 0.1 at%, the effect of suppressing the warpage of the sputtering target cannot be obtained. On the other hand, when the content exceeds 23 at%, the target density is lowered, the strength of the target is lowered, and cracks are likely to occur. After that. The proportion of In which is actively contained in In is preferably in the range of 0.1 to 23 at%, particularly in the range of 1 to 10 at%.

In the sputtering target of the present invention, the Fe-Mo-O-based compound (Fe-Mo-based composite oxide) is present in a phase of the Fe ₂ Mo ₃ O ₈ phase which is mainly a composite oxide, relative to the MoO ₂ phase. And the ratio of the Fe ₃ O ₄ phase, the diffraction peak intensity measured by XRD preferably satisfies the following two conditions. Here, "diffraction peak intensity" means the number of counts per minute (cps) of the diffraction peak. And the XRD system utilizes a powder X-ray diffraction method using a Cu-Kα line.

As a first condition, the diffraction peak intensity of the (002) plane of the Fe ₂ Mo ₃ O ₈ phase is preferably 1.5% or more of the diffraction peak intensity of the (011) plane of the MoO ₂ phase, or is Fe ₃ O ₄ phase. The diffraction peak intensity of the (311) plane is 1.5% or more. When this condition is not satisfied, the effect of suppressing the occurrence of cracks cannot be sufficiently obtained.

Further, as a second condition, the diffraction peak intensity of the (002) plane of the Fe ₂ Mo ₃ O ₈ phase is preferably 300% or less of the diffraction peak intensity of the (011) plane of the MoO ₂ phase, or is Fe ₃ O _{4 .} The phase of the (311) plane is less than 300% of the peak intensity. When this condition is not satisfied, the resistance value of the target is too high, and it is difficult to use the target for DC sputtering.

Whether or not the sputter target satisfies the above conditions can be easily investigated by XRD. The analysis results of the examples as XRD are shown in Figs. 3 and 4.

Fig. 3 shows an X-ray diffraction result for an example of a sputtering target containing a large amount of composite oxide (the material A of the present invention is equivalent to the embodiment 3 described later), and Fig. 4 shows a sputtering for a composite oxide containing more Another example of the target (the material B of the present invention corresponds to Example 4 described later) is subjected to X-ray diffraction. On the other hand, Fig. 5 shows an X-ray diffraction result for an example of a sputtering target containing a very small (substantially free) composite oxide (comparative material: corresponding to Comparative Example 2 described later).

In FIGS. 3 to 5, the vertical axis represents the number of counts per minute (cps) of the diffraction intensity, the peak P3 corresponds to the diffraction peak of the (002) plane of the Fe ₂ Mo ₃ O ₈ phase, and the peak P2 corresponds to MoO _{2 .} The diffraction peak of the (011) plane, the peak P1 corresponds to the diffraction peak of the (311) plane of the Fe ₃ O ₄ phase.

It can be seen that the present invention A of FIG. 3 and the inventive material B of FIG. 4 have the intensity (cps) of the peak P3 of 1.5% or more of the intensity of the peak P2 and 1.5% or more of the intensity of the peak P1, and sufficiently satisfy the above. In the first condition, the intensity (cps) of the peak P3 is 300% or less of the intensity of the peak P2 and 300% or less of the intensity of the peak P1, and the second condition is sufficiently satisfied.

In contrast, the comparison of substantially no composite oxide shown in FIG. The intensity of the material peak P3 did not reach 1.5% of the intensity of the peak P2, and did not reach 1.5% of the intensity of the peak P1, and did not satisfy the above first condition.

Further, according to experiments by the inventors of the present invention, when a sputtering target containing Fe, Mo, or (In) is produced by a high-temperature sintering method such as hot pressing, it is confirmed that Fe ₂ Mo is preferentially formed as a composite compound in a target. ₃ O ₈ phase. In some cases, an FeMoO ₄ phase was formed in addition to the Fe ₂ Mo ₃ O ₈ phase, but it was confirmed that the absolute amount of the FeMoO ₄ phase was usually less than the absolute amount of the Fe ₂ Mo ₃ O ₈ phase. Therefore, it is considered that the presence or absence of the composite oxide in the target is only investigated for the Fe ₂ Mo ₃ O ₈ phase. Therefore, the existence of the composite oxide is better than the diffraction peak intensity of the (002) plane of the Fe ₂ Mo ₃ O ₈ phase of XRD.

Further, the particle diameter (crystal grain size) in the cross-sectional structure of the target of the present invention is not particularly limited, but is preferably 20 μm or less on average, and more preferably 10 μm or less.

The sputtering target as described above can effectively suppress cracking due to temperature change or the like at the time of production or sputtering using the film, and the like, thereby improving yield and improving productivity. Therefore, the sputtering target containing In as a metal component can effectively suppress the occurrence of warpage, and therefore, the yield and productivity can be further improved.

[Production method]

Next, a method of manufacturing the sputtering target of the present invention will be described.

In the production of the sputtering target of the present invention, the oxide powder of each metal component is preferably mixed, and the mixed powder is sintered at a high temperature, particularly at a temperature in the range of 840 to 950 ° C, to obtain a sintered body as a target. For example, it is preferable to prepare Fe ₃ O ₄ powder as Fe oxide powder, MoO ₂ powder as Mo oxide powder, and In ₂ O ₃ powder as In oxide powder, and mix them in a specific metal component ratio. The high-temperature sintering is performed by pressurization by a so-called hot press method.

Here, according to experiments by the present inventors, it has been found that sintering is performed only for the purpose of obtaining a sintered body structure in which only the oxide phase of Fe alone and the oxide phase of Mo alone (and the oxide phase of In alone) are mixed. It is sufficient that the temperature is about 700 to 800 ° C, but in order to form the composite oxide phase as described above, sintering at a high temperature of 840 ° C or higher is suitable.

In other words, it is presumed that by sintering at a high temperature of 840 ° C or higher, Fe, Mo, (In) is carried out between the Fe oxide powder particles and the Mo oxide powder particles (and further the In oxide powder particles) which are in contact with each other as described above. ), O is mutually diffused (solid diffusion), and as a result, a Fe—Mo(—In) composite oxide is formed.

When the heating temperature at the time of sintering is less than 840 ° C, the composite oxide cannot be sufficiently formed. On the other hand, when it exceeds 950 ° C, the resistance is increased and DC sputtering is difficult. Therefore, the sintering temperature is preferably in the range of 840 to 950 °C.

Moreover, the pressure at the time of pressure sintering by hot press is not particularly limited, but it is usually preferably about 100 to 500 kgf/cm ² . The sintering time (holding time in the above temperature range) is also not particularly limited, and it is usually kept for 2 to 5 hours.

Further, the particle diameter of each oxide powder constituting the mixed powder to be sintered is not particularly limited, but is usually measured by a median diameter (d50 value). It can be about 0.2~7μm.

If the target obtained as described above is processed into a specific shape, a specific size by a suitable machining process, and bonded to a backing plate made of copper or the like as needed, the sputtering can be finally used for sputtering. target.

[Optical function film]

When a sputtering target of the target of the present invention as described above is used, a film is sputter-deposited on a substrate such as a metal thin film to form an optical functional film. The composition of the optical functional film is substantially the same as that of the sputtering target as described above. That is, the optical functional film contains Fe and Mo (and further In) as a metal element, and some or all of the aforementioned metal elements exist in the form of an oxide.

Therefore, in particular, if the content of the metal element as Fe in the total metal component in the sputtering target is 20 to 95 at%, and the content of the metal element as Mo is 5 to 80 at%, the optical functional film becomes the Fe in all the metal components. The content of the metal element is about 20 to 95 at%, and the content of the metal element of Mo is about 5 to 80 at%. Further, when the sputtering target contains In as a metal element, and the content of the metal element as In in all the metal components is 0.1 to 23 at%, the optical functional film also contains In, and the content of the metal element as In in all the metal components is about 0.1~23at%.

In such an optical functional film, the average reflectance is suppressed to 30% or less, and the maximum reflectance change before and after the constant temperature and humidity test can be suppressed to 15% or less, so that the reliability of reflectance characteristics is also high. Therefore, by forming a film on a metal thin film (for example, a wiring pattern of a touch panel), it can be effectively used as an optical functional film having the effect of concealing the metallic luster of the metal thin film.

Further, the etching property is also good, and the chemical resistance and the weather resistance are also good, and the reliability and stability after etching and etching are also good, and for example, on the metal thin film (for example, a wiring pattern of a touch panel) as described above. It can be effectively used for film formation and etching.

Examples and comparative examples of the present invention are shown below. The following examples are intended to illustrate the effects of the present invention, and the technical scope of the present invention is of course not limited to the configurations, processes, and conditions described in the examples.

[Examples]

[Manufacture of sputtering target]

Prepare MoO ₂ powder having a median diameter (d50) of 4 μm, In ₂ O ₃ powder having a median diameter of 1 μm, and Fe ₂ O ₃ powder having a median diameter of 1 μm, and in some cases, MoO ₂ powder and Fe ₂ The O ₃ powder was mixed, and in another example, the MoO ₂ powder and the Fe ₂ O ₃ powder were mixed with the In ₂ O ₃ powder to prepare a mixed powder. In other words, each of the powders was weighed into a ball mill as a mixing device by using Mo, Fe, and In as the metal components in the composition ratios of Comparative Examples 1 to 3 and Tables 1 to 18 in Table 1. And mix.

Each of the obtained mixed powders was subjected to hot pressurization for 3 hours at a temperature of 700 to 1000 ° C in a vacuum at a pressure of 200 kgf / cm ² to prepare a sintered body (sputter target).

Each of the obtained sintered bodies was machined to have a diameter of 152.4 mm and a thickness of 6 mm, and then attached to a backing plate made of Cu using In solder to form a sputtering target.

[Formation by Sputtering = Fabrication of Optical Functional Film]

Using such a sputtering target, a film was formed by sputtering on a glass substrate, and an optical functional film was produced and tested.

The film formation conditions of the sputtering are as follows.

. Power supply: DC power supply

. Electricity: 600W

. Gas pressure: Ar=50sccm

. T-S distance (distance between target substrates): 70mm

. Substrate temperature: room temperature

. Substrate: Glass substrate (trade name: Eagle XG)

The sintered body (sputter target) obtained by high-temperature sintering as described above was examined for the presence or absence of the composite oxide (Fe-Mo-O-based compound), and the sputtering target was evaluated and sputter-deposited as follows. The results of evaluation of the optical functional film are shown in Tables 1 and 2.

[The presence or absence of a composite oxide (Fe-Mo-O compound)]

The presence or absence of the composite oxide (Fe-Mo-O-based compound) was investigated by XRD for each sputtering target. The XRD condition was carried out by a powder method using a Cu-Kα line as an X-ray.

Here, as described above, when a sputtering target containing Fe, Mo, or (In) is produced by a high-temperature sintering method such as hot pressing, it is confirmed that the composite oxide in the target preferentially forms Fe ₂ Mo ₃ O. ₈ phases. Further, in addition to the Fe ₂ Mo ₃ O ₈ phase, a FeMoO ₄ phase was formed, but it was confirmed that the absolute amount of the FeMoO ₄ phase was less than the absolute amount of the Fe ₂ Mo ₃ O ₈ phase. Therefore, the presence or absence of the composite oxide in the target is investigated for the diffraction peak intensity of the (002) plane for the Fe ₂ Mo ₃ O ₈ phase (counts per second: cps), and the intensity is MoO ₂ phase (011) When the intensity of the diffraction peak of the surface is 1.5% or more, or 1.5% or more of the intensity of the diffraction peak of the (311) plane of the Fe ₃ O ₄ phase, it is determined that the composite oxide exists, and the composite oxidation is shown in Table 1. "The presence or absence of the object" is described as "Yes", which is 1.5% of the intensity of the diffraction peak that does not reach the (011) plane of the MoO ₂ phase and does not reach the diffraction peak of the (311) plane of the Fe ₃ O ₄ phase. When the strength was 1.5%, it was judged that the composite oxide was not present, and it was described as "None" in the column "The presence or absence of the composite oxide" in Table 1.

Further, in each of the comparative examples and the respective examples, the diffraction peak intensity of the (002) plane of the Fe ₂ Mo ₃ O ₈ phase was 300% or less of the intensity of the diffraction peak of the (011) plane of the MoO ₂ phase. Further, it is 300% or less of the intensity of the diffraction peak of the (311) plane of the Fe ₃ O ₄ phase.

[Evaluation of Sputtering Targets]

<Cracking occurrence evaluation>

The occurrence of cracks in the sputtering target was investigated as follows.

In other words, the target material after sintering and before processing was inspected by the penetration flaw test to evaluate the occurrence of crack occurrence, and when the indication pattern was visually detected, it was described as "Yes" in the "crack" column of Table 1.

<evamination of warpage occurrence>

In addition, the occurrence of warpage of the target was investigated as follows.

That is, for the target material after sintering and before processing, with straight edges Investigate the amount of warpage with the gap range. When the amount of warpage is 0.5 mm or less, since there is no particular problem in processing, it is determined that there is no warpage. On the other hand, when the amount of warpage exceeds 0.5 mm, the degree of work becomes large and the yield is deteriorated, so that it is determined that there is Warping.

<density ratio and resistance evaluation>

Investigate the density ratio against the target and investigate the resistance value. The density ratio is determined by measuring the ratio of the size to the weight and the true density (100%). The resistance value was measured using a four-probe method. Further, the resistance value was measured using a resistance measuring instrument LORESTA GP manufactured by Mitsubishi Chemical Corporation.

[As an evaluation of optical functional film]

Further, with respect to each of the sputtering targets of Examples 1 to 18 and Comparative Examples 1 to 3, an optical functional film (laminated film) laminated on the metal thin film to form a film, and the average reflectance and the constant temperature and humidity test were investigated as follows. The maximum value of the change in reflectivity before and after.

<Measurement of average reflectance>

Sputtering was carried out under the same conditions as above. Further, a film is deposited on the glass substrate in the order of an oxide film (optical functional film) having a thickness of 50 nm, copper, aluminum, silver or molybdenum having a thickness of 200 nm. Further, in Example 16, Al was used as the metal film, in Example 17, Ag was used as the metal film, and in Example 18, Mo was used as the metal film, and in the other examples and comparative examples, Cu was used as the metal film. Metal film is metal wiring For its film formation, individual metal sputtering targets are used.

Next, the reflectance was measured for the laminated film formed on the glass substrate as described above. This measurement was performed using a spectrophotometer (U4100 manufactured by Hitachi Ltd.) from the side of the glass substrate at a wavelength of 400 to 800 nm. Furthermore, the four samples prepared in the same manner were measured, and the obtained measured values were averaged to obtain an average reflectance, which is the "average reflectance (%) in the film" in Table 2.

<Measurement of the maximum value of reflectance change>

Further, a constant temperature and humidity test was carried out on the laminated film formed on the glass substrate as described above under the test conditions shown below.

. Temperature: 85 ° C

. Humidity: 85%

. Hold time: 250 hours

After the constant temperature and humidity test, the reflectance in the wavelength range of 400 to 800 nm was measured in the same manner as described above, and the reflectance after the test was measured. On the other hand, before the constant temperature and humidity test, the reflectance measurement value similar to the above was used as the pre-test reflectance, and the reflectance change at each wavelength of 400, 500, 600, 700, and 800 nm before and after the constant temperature and humidity test was determined. . Among the above five wavelengths, the maximum value of the change in reflectance is referred to as "the maximum value of the reflectance change" shown in Table 2.

As shown in Table 1, in the sputtering targets of Comparative Examples 1 to 3 which were produced under the conditions of a sintering temperature of less than 840 ° C, substantially no composite oxide (Fe-Mo-O-based compound) was formed, and as a result, the target was confirmed. Cracking occurred.

On the other hand, in the sputter targets of Examples 1 to 18 which were produced at a sintering temperature higher than 840 ° C, as shown in Table 1, composite oxidation was observed. The product (Fe-Mo-O compound) was produced, and as a result, it was confirmed that the target was not cracked. However, the sputtering target of Example 4 which was produced at a sintering temperature higher than 1000 ° C had a low density ratio and a high resistance value.

Further, in the sputtering targets of Examples 1 to 18, Examples 1 to 4 are examples in which In contains no metal element, and Example 5 contains In, but the content thereof is less than 0.1 at%, which is an example. Examples 1 to 5 were warped. On the other hand, Examples 6 to 9 containing 0.1 at% or more of In can suppress the occurrence of warpage. However, in Example 9, since In exceeded 23 at%, the density ratio was slightly lower.

Examples 10 to 13 are examples in which In is not included, and the ratio of Mo to Fe is changed. In Examples 10 to 13, Example 11 in which Fe is 20 to 95 at% and Mo is 5 to 80 at%. There is no particular problem in 12, but in Example 10 in which Mo is less than 5 at% and Fe is more than 95 at%, the average reflectance of the film after sputtering film formation exceeds 30%. On the other hand, in Example 13 in which Mo was more than 80 at% and Fe was less than 20 at%, the maximum change in reflectance of the film after sputtering film formation exceeded 15%.

Further, in Examples 14 and 15, the examples in which In and Fe and Mo were close to the upper limit or the lower limit in the above range were used, and the examples ensured good characteristics.

[Industrial availability]

An optical functional film suitable for use in a large touch panel, having low reflectance and high reliability can be provided.

1‧‧‧Mo oxide phase region

2‧‧‧Fe oxide phase region

3‧‧‧Fe-Mo composite oxide phase (Fe-Mo-O compound phase)

Claims (8)

A sputtering target characterized in that Fe and Mo are contained as a metal element, and part or all of the metal element is present in the form of an oxide, and the oxide phase contains an Fe-Mo-O compound. The sputtering target of claim 1, wherein the metal element content of Fe is 20 to 95 at%, and the metal element content of Mo is 5 to 80 at%. A sputtering target according to claim 1, which further contains In as a metal element. In the sputtering target of claim 3, among all the metal components, the content of the metal element as In is 0.1 to 23 at%. The sputtering target according to claim 1, wherein the Fe-Mo-O compound is mainly composed of a Fe ₂ Mo ₃ O ₈ phase. The sputtering target of claim 5, wherein the diffraction peak intensity of the (002) plane of the Fe ₂ Mo ₃ O ₈ phase is 1.5% or more of the diffraction peak intensity of the (011) plane of the MoO ₂ phase, or is Fe _The intensity of the diffraction peak of the (311) plane of the ₃ O ₄ phase is 1.5% or more, and is less than 300% of the diffraction peak intensity of the (011) plane of the MoO ₂ phase, and is the Fe ₃ O ₄ phase (311) The diffraction peak intensity of the surface is less than 300%. A method for producing a sputtering target, which is a method for producing a sputtering target according to any one of claims 1 to 6, which is characterized in that a mixed powder of Fe oxide powder and Mo oxide powder or Fe is oxidized. The powder of the powder and the mixed powder of the Mo oxide powder and the In oxide powder are sintered at a temperature in the range of 840 to 950 °C. An optical functional film which is used in a target, wherein the sputtering target material according to any one of claims 1 to 6 is used, and an optical functional film formed by an oxide adjacent to the metal thin film and formed by sputtering is used. The characteristic is that the average optical reflectance of the optical functional film measured from the side not adjacent to the metal film is 30% or less.