JP6409654B2 - Sputtering target material, manufacturing method thereof, and optical functional film - Google Patents

Description

  The present invention uses a sputtering target material for forming an optical functional film laminated on a metal thin film to reduce metal reflection by sputtering, a method for producing the sputtering target material, and the sputtering target material. The present invention relates to an optical functional film formed by sputtering.

  In recent years, a projected capacitive touch panel has been adopted as input means for portable terminal devices and the like. In this type of touch panel, if a finger is brought close to the sensing electrode arranged on the touch panel substrate, a capacitance is formed between the fingertip and the electrode, and a control circuit or the like is formed based on the change in the capacitance. The touch position is detected by. In order to detect the touch position, a sensing electrode is required, and this sensing electrode is usually formed by patterning, for example, an X electrode extending in the X direction on one surface of the transparent substrate. A method of providing Y electrodes extending in the Y direction and arranging them in a lattice shape is common (see, for example, Patent Document 1).

  On the other hand, color filters intended for color display are employed in flat panel displays typified by liquid crystal display devices and plasma displays. In this color filter, micro color filters of red (R), 碧 (G), and blue (b) are formed in a matrix corresponding to each pixel. For the purpose of improving the color purity and improving the visibility, a black member called a black matrix is formed.

As this black matrix (hereinafter referred to as “BM”), chromium (Cr) or a chromium compound is used, and a light shielding film made of a metal chromium single layer film, a laminated film of metal chromium and chromium oxide, or Cr metal. It has been proposed to form a low reflection film such as a laminated film of Cr oxide and Cr nitride (see, for example, Patent Document 2).
Furthermore, 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) Alternatively, it has 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 such as molybdenum (Mo) or silver (Ag) is used. When the solar cell panel of such an aspect is viewed from the back surface side, if the metal film as the back electrode is visible as it is, it exhibits a metallic luster and is not good as a product. Therefore, usually, the metallic luster is concealed by sticking 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 a touch position on a conventional touch panel. However, with the increase in the area of the touch panel, the use of the ITO thin film increases the resistance and the detection accuracy. The problem of deteriorating has arisen. 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, the metal wiring using such a metal thin film exhibits high reflection characteristics and reflects external light, so that the metallic luster of the wiring pattern is visible from the outside of the panel, making it difficult to use the touch panel. .

Therefore, the present invention has developed a film (hereinafter referred to as “optical functional film”) that can reduce the metallic luster of the wiring pattern of the touch panel screen by forming a film on the wiring of the metal thin film in the touch panel by sputtering. In order to develop an optimum sputtering target for forming such an optical functional film by sputtering, earnest experiments and researches were repeated.
In that process, attention was paid to the fact that Mo oxide, In oxide, and the like have light absorption characteristics with respect to external light in the visible light region, in other words, the appearance is black because the reflectance is extremely low. That is, by forming an oxide film made of Mo oxide or an oxide film made of Mo oxide and In oxide as an optical functional film on the metal thin film wiring, the metallic luster of the wiring pattern is obtained. Recognized that can be reduced.

  Further, the oxide film made of Mo oxide or the oxide film made of Mo oxide and In oxide is left as it is, as described below, at the time of etching or after that (chemical resistance, In order to solve the problem and improve the reliability of the optical functional film, it has been found that it is effective to add an oxide of Fe.

  That is, when this kind of oxide film is formed on the touch panel wiring as an optical functional film, if the productivity is taken into consideration, the above oxide film is formed on the surface of the metal thin film formed on the touch panel substrate. It is preferable to form a wiring pattern after film formation. In this wiring patterning, usually, after forming a pattern mask, the metal thin film and the oxide film are etched with an etching solution. In such patterning etching, it has been found that the oxides of Mo and In are inferior in reliability (chemical resistance and weather resistance) while being excellent in etchability with an etchant. The above-described etching property means that the metal thin 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.

  On the other hand, in order to improve the reliability of the oxide film made of Mo oxide or the oxide film made of Mo oxide and In oxide, the knowledge that adding Fe is effective is obtained. It was. In other words, by using an optical functional film containing not only the oxide of Mo and oxide of In but also the oxide of Fe, not only the metallic luster of the wiring pattern can be reduced, but also the reliability as described above can be obtained. Recognized that it can be improved.

  In order to form such an optical functional film on a metal thin film, sputtering is performed using a sputtering target mainly composed of Mo oxide or Mo oxide and In oxide, and Fe oxide. It was found that film formation was effective. That is, when a sputtering film is formed by using a sputtering target mainly composed of Mo oxide or Mo oxide and In oxide, and Fe oxide, as described above, Mo oxide or Mo oxide and It was recognized that an optical functional film having a low reflectivity and high reliability can be obtained mainly composed of In oxide and Fe oxide.

  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 further serves as protection of the back electrode of the solar cell panel, It could be provided instead and proved suitable for concealing their metallic luster.

  By the way, in order to put the optical functional film as described above into practical use, further experiments and research were conducted on a sputtering target material for forming the optical functional film by sputtering. It was found that cracks are likely to occur in a sputtering target material having a structure in which oxides (or further In oxides) are mixed. That is, in manufacturing a target material in which this kind of oxide phase is mixed, it is preferable to use oxide powder as a raw material and sinter the mixed powder at a high temperature by hot pressing or the like. It has been found that there is a problem that cracks occur in the sintered body of the target material during the cooling process after sintering, or that the target cracks when the target becomes high temperature during sputtering. Thus, if cracks occur during the production of a target material or during sputtering film formation using the target material, the yield decreases and the productivity is hindered.

  The present invention has been made in the background as described above, and has low reflectivity, and is ideal for concealing the metallic luster and excellent in reliability if it is formed by sputtering on a metal thin film. In addition to being able to form an optical functional film, the sputtering target material itself is provided with a sputtering target material that is less susceptible to cracking, and a method for producing such an excellent sputtering target material is also provided. At the same time, it is a basic object to provide an optical functional film formed by sputtering using the target material as a sputtering target.

Further research was conducted to solve the problem that cracking was likely to occur in the sputtering target having a structure in which Mo oxide or Mo oxide / In oxide and Fe oxide were mixed as described above. However, it has been speculated that the main cause of the occurrence of cracks in the sputtering target having the above structure is that the difference in thermal expansion coefficient between Mo oxide and Fe oxide (difference in linear expansion coefficient) is large.
That is, the linear expansion coefficient of Mo oxide is about 4 × 10 ⁻⁶ / K, whereas the linear expansion coefficient of Fe oxide is about 10 × 10 ⁻⁶ / K, and the difference between them is large. In the sputtering target material having a structure in which the Mo oxide phase and the Fe oxide phase are mixed and mixed, the expansion and contraction at the time of temperature change are uneven inside, and a large thermal stress is generated inside, It is assumed that cracks are likely to occur.

  When further research was carried out, not only the phase of Mo oxide (or Mo oxide and In oxide) and the phase of Fe oxide were mixed, but also Mo, Fe and O (oxygen). And (or further with In), that is, it is found that cracking can be suppressed by forming a structure including a phase composed of a composite oxide of Mo, Fe, and (In). It came to an eggplant.

Therefore, in the sputtering target material according to the basic aspect (first aspect) of the present invention, the metal component is composed of Fe and Mo, and a part or all of the metal element is present in the form of an oxide, and is oxidized. It is characterized in that the physical phase contains an Fe—Mo—O-based compound.
In addition, said Fe-Mo-O type compound can also be called Fe-Mo type complex oxide, and may only be called a complex oxide below.

  Further, the sputtering target material according to the second aspect is the sputtering target material according to the first aspect, wherein the content of Fe as a metal element in all metal components is 20 to 95 at%, the content of Mo as a metal element The amount is 5 to 80 at%.

  Furthermore, the sputtering target material according to the third aspect is characterized in that the sputtering target material according to the first or second aspect further contains In as a metal element.

  Moreover, the sputtering target material according to the fourth aspect is characterized in that, in the sputtering target material according to the third aspect, the content of In as a metal element among all metal components is 0.1 to 23 at%. To do.

Moreover, the sputtering target material according to the fifth aspect is the sputtering target material according to any one of the first to fourth aspects, wherein the Fe—Mo—O-based compound mainly comprises an Fe ₂ Mo ₃ O ₈ phase. It is a feature.

Furthermore, the sputtering target material according to the sixth aspect is the same as the sputtering target material according to the fifth aspect, except that the intensity of the diffraction peak in the (002) plane of the Fe ₂ Mo ₃ O ₈ phase is in the (011) plane of the MoO ₂ phase. 1.5% or more of the diffraction peak intensity, or 1.5% or more of the diffraction peak intensity in the (311) plane of the Fe ₃ O ₄ phase, and the diffraction peak intensity in the (011) plane of the MoO ₂ layer It is characterized by being 300% or less and 300% or less of the intensity of the diffraction peak on the (311) plane of the Fe ₃ O ₄ phase.

Moreover, in the 7th aspect, the manufacturing method of the sputtering target material of any one of the said 1st-6th aspect is prescribed | regulated.
That is, the manufacturing method of the sputtering target material of the seventh aspect comprises a mixed powder of Fe oxide powder and Mo oxide powder, or a mixed powder of Fe oxide powder, Mo oxide powder and In oxide powder, Sintering is performed at a temperature within the range of 840 to 950 ° C.

Furthermore, in the eighth aspect, an optical functional film is defined.
That is, the optical functional film of the eighth aspect is an optical functional film made of an oxide formed by sputtering adjacent to a metal thin film using any one of the first to sixth sputtering target materials as a target. And the average light reflectance measured from the side which is not adjacent to the said metal film in the said optical function film | membrane is 30% or less, It is characterized by the above-mentioned.

  According to the sputtering target material of the present invention, it is possible to effectively suppress the generation of cracks during its production or during sputtering film formation using the same, thereby improving yield and improving productivity. Can be made. Furthermore, in the sputtering target material containing In as a metal component, it is possible to effectively suppress the occurrence of warpage, and thus yield and productivity can be further improved.

It is a schematic diagram which shows an example of the cross-sectional structure | tissue in the sputtering target material of this invention. It is a schematic diagram which shows an example of the cross-sectional structure | tissue in the sputtering target material which is a comparative material with respect to this invention. It is a chart figure which shows an example of the measurement result by XRD in the sputtering target material of this invention. It is a chart figure which shows the other example of the measurement result by XRD in the sputtering target material of this invention. It is a chart figure which shows an example of the measurement result by XRD in the sputtering target material which is a comparative material with respect to this invention.

  Hereinafter, the sputtering target material of the present invention, the manufacturing method thereof, and the optical functional film formed by sputtering using the sputtering target material of the present invention will be described in more detail.

[Sputtering target material]
The sputtering target material of the present invention basically contains Fe and Mo as metal elements, and part or all of the metal elements are present in the form of oxides, and in the oxide phase, Fe -Mo-O type compound (Fe-Mo type complex oxide) is contained.
Here, in the target material, an oxide of Fe alone (typically Fe ₃ O ₄ ) and an oxide of Mo alone (typically MoO ₂ ) are also present. By containing an oxide (typically Fe ₂ Mo ₃ O ₈ , and partly FeMoO ₄ may be included), generation of cracks can be suppressed.

  Such an effect of suppressing cracking due to the presence of the Fe—Mo based complex oxide is found by experiments of the present inventors, but cracking can be prevented by the presence of the Fe—Mo based complex oxide. The effect is thought to be due to the following reasons.

That is, the Fe—Mo based composite oxide has a linear expansion coefficient of about 7 × 10 ⁻⁶ / K, and is an intermediate between the linear expansion coefficient of the oxide of Fe alone and the linear expansion coefficient of the oxide of Mo alone. The linear expansion coefficient value. Moreover, when such a Fe-Mo type complex oxide phase sinters mixed oxide powder of Fe oxide powder and Mo oxide powder at a high temperature of about 840 ° C. or higher, for example, to produce a target material, It is usually generated so as to be interposed between an oxide of Fe alone and an oxide of Mo alone. Therefore, it is considered that the Fe—Mo based complex oxide functions as a buffer material between the oxide of Fe alone and the oxide of Mo alone, and is effective in generating cracks.
Moreover, as described above, the Fe—Mo composite oxide produced between the Fe oxide and the Mo oxide by the high temperature sintering method is between the Fe oxide powder particles and the Mo oxide powder particles that are in contact with each other. , Fe, Mo, O, as a result of interdiffusion (solid diffusion), between the adjacent Fe oxide phase and the Fe—Mo based complex oxide phase in the obtained target material (sintered body), and The adjacent Mo oxide phase and the Fe—Mo based composite oxide phase are all firmly bonded by solid phase diffusion.
It is presumed that the above two actions combine to make it difficult for cracks to occur when the temperature changes.

Here, when the target material is manufactured by sintering at a high temperature of about 840 ° C. or higher as described above, the Fe—Mo based complex oxide phase (Fe—Mo—O based) in the target material (sintered body). It has been confirmed by experiments by the present inventors that the compound phase) exists between an oxide of Fe alone and an oxide of Mo alone. As an example, FIG. 1 schematically shows a cross-sectional structure of a target material (sintered body) obtained by sintering at 880 ° C. according to Example 2 described later. In FIG. 1, a hatched region 1 is a region where the Mo concentration is high and does not contain Fe, and is a region that is discriminated as a Mo oxide phase, and a dotted region 2 is a region where the Fe concentration is high. And it is an area | region which does not contain Mo, and is an area | region discriminate | determined from a Fe oxide phase, Furthermore, the white area | region 3 contains Mo and Fe, and Mo density | concentration and Fe density | concentration are intermediate | middle, Fe This is a region discriminated from a Mo-based composite oxide phase (Fe-Mo-O-based compound phase). From FIG. 1, it is clear that an Fe—Mo based complex oxide phase (Fe—Mo—O based compound phase) 3 exists between the Mo oxide phase region 1 and the Fe oxide phase region 2. It is.
For comparison, FIG. 2 schematically shows a cross-sectional structure of a target material (sintered body) obtained by sintering at 700 ° C. in Comparative Example 1 described later. From FIG. 2, the shaded Mo oxide phase 1 and the dotted Fe oxide phase region 2 are almost directly adjacent to each other, and an Fe—Mo based complex oxide phase (Fe—Mo—O based compound). It is clear that the phase) is substantially absent.

  The presence of the Fe—Mo—O compound (Fe—Mo complex oxide) in the sputtering target material can be confirmed by XRD (X-ray diffraction), and the Fe—Mo—O compound ( The abundance ratio of Fe—Mo composite oxide) (ratio to the abundance of the oxide of Fe alone or the oxide of Mo alone) can also be measured by XRD, which is preferable for the above abundance ratio. This will be described again together with the description of the range described later.

  In the sputtering target material of the present invention, the proportion of Fe in all metal components (content ratio as a metal element) is in the range of 20 to 95 at%, and the ratio of Mo (content ratio as a metal element) is It is desirable that it is 5 to 80 at%. That is, in the sputtering target material of the present invention, all or part of Fe and Mo are present in the form of oxides (single oxide and composite oxide), but include Fe and Mo in the oxide. The proportion of the total metal component is preferably 20 to 95 at% for Fe and 5 to 80 at% for Mo.

  When an optical functional film is obtained by sputtering using an oxide-based sputtering target, the composition of the optical functional film is substantially the same as the composition of the sputtering target. Therefore, the composition of the sputtering target material may be selected so that the characteristics required for the optical functional film can be satisfied. From such a viewpoint, the desired composition of the sputtering target material as described above is set to Fe for all metal components. The content ratio as a metal element is within a range of 20 to 95 at%, and the content ratio as a metal element of Mo is set to 5 to 80 at%.

  Here, when Mo of all the metal components is less than 5 at%, the average reflectance does not become 30% or less at a wavelength of 400 to 800 nm in the visible light. The gloss cannot be suppressed. Therefore, it is not preferable as an optical functional film which is the final purpose in the present invention.

  On the other hand, if Mo of all metal components exceeds 80 at%, the maximum value of the reflectance change before and after the constant temperature and humidity test is 15% or more, so the reflectance change before and after the constant temperature and humidity test is suppressed. In order to improve the reliability of the reflectance characteristics, Mo is preferably 80 at% or less. If Mo exceeds 60%, the maximum value of the reflectance change is 10 at% or more, and if Mo exceeds 50 at%, the maximum value of the reflectance change is 5% or more. Therefore, the lower the Mo ratio, the better the reliability of the reflectance characteristics as the optical functional film. However, if Mo is small, the average value of the reflectance becomes large. Therefore, from these considerations, it is desirable that Mo be within the range of 5 to 80 at%, particularly within the range of 25 to 60 at%. .

  When the proportion of Fe in the total metal components is less than 20 at%, the maximum reflectance change before and after the constant temperature and humidity test is 15% or more in the wavelength range of 400 to 800 nm in the visible light. The reliability of reflectance characteristics as a film is lowered. If Fe exceeds 95 at%, the reflectance does not become 30% or less at a wavelength of 400 to 800 nm in visible light, and the metallic luster of the wiring pattern can be suppressed by reflection of the optical functional film (laminated film). It becomes impossible and it becomes unpreferable as an optical function film aimed at by the present invention. In addition, the ratio of Fe is preferably within the range of 40 to 75 at%, even within the range of 20 to 95 at%.

  Furthermore, the sputtering target material of the present invention may contain In as a metal component as necessary. That is, it has been confirmed that when the Fe—Mo-based composite oxide phase as described above is generated in the target material, it tends to be warped as a thin plate. However, it has been found that the generation of warpage can be suppressed by adding In as a metal element (actually, adding In as an oxide).

Here, in general, when performing sputtering, a thin plate made of a target material is generally bonded to the surface of a backing plate made of Cu or the like with solder or the like and used for sputtering. In that case, if the warpage of the target material thin plate is large, it may be difficult to evenly adhere to the backing plate, or it may hinder automated handling for adhesion, which may impair productivity. However, the addition of In makes it possible to suppress the warpage and avoid the occurrence of such a problem. In the target, In is mainly contained in the form of In ₂ O ₃ , but it may be contained in the form of a complex oxide like Mo and Fe. As a complex oxide containing In, for example, a Fe—Mo—In complex oxide (Fe—Mo—In—O compound, or a Fe—In complex oxide (Fe—In—O compound, or Mo—) In-based composite oxides (Mo—In—O compounds and the like can be given.

  When In is positively contained as described above, the In content as the metal component is preferably in the range of 0.1 to 23 at% as a ratio of the total metal component. If the In metal component is less than 0.1 at%, the effect of suppressing the warpage of the sputtering target cannot be obtained. On the other hand, if it exceeds 23 at%, the density of the target material decreases, the strength of the target material decreases, and cracking occurs. There is a risk of problems such as being easier. In addition, the ratio of In when positively containing In is preferably within the range of 1 to 10 at%, even within the above range of 0.1 to 23 at%.

In the sputtering target material of the present invention, the abundance ratio of the Fe—Mo—O-based compound (Fe—Mo-based composite oxide), particularly the MoO ₂ phase of the Fe ₂ Mo ₃ O ₈ phase which is the main composite oxide. As for the ratio to the Fe ₃ O ₄ phase, the intensity of the diffraction peak by XRD preferably satisfies the following two conditions. The “diffraction peak intensity” mentioned here means the number of counts per second (cps) of the diffraction peak. XRD is based on a powder X-ray diffraction method using Cu-Kα rays.

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

The second condition is that the intensity of the diffraction peak due to the (002) plane of the Fe ₂ Mo ₃ O ₈ phase is not more than 300% of the intensity of the diffraction peak due to the (011) plane of the MoO ₂ phase. It is preferably 300% or less of the intensity of the diffraction peak due to the (311) plane of the ₃ O ₄ phase. When this condition is not satisfied, the electric resistance value of the target material becomes too high, and it becomes difficult to perform DC sputtering using the target material.

  Whether or not the sputtering target material satisfies the above conditions can be easily examined by XRD. Examples thereof are shown in FIGS. 3 and 4 as analysis results by XRD.

FIG. 3 shows the result of X-ray diffraction performed on an example of a sputtering target material containing a large amount of complex oxide (present invention material A: equivalent to Example 3 described later), and FIG. 4 shows the complex oxide. The result of having performed X-ray diffraction about the other example (this invention material B: equivalent to Example 4 mentioned later) of sputtering target material in which many are contained is shown. On the other hand, FIG. 5 shows the result of X-ray diffraction performed on an example of a sputtering target material (comparative material: equivalent to Comparative Example 2 described later) having a very small amount of complex oxide (not substantially contained).
3 to 5, the vertical axis represents the diffraction intensity in counts per second (cps), and the peak P3 corresponds to the diffraction peak in the (002) plane of the Fe ₂ Mo ₃ O ₈ phase. The peak P2 corresponds to the diffraction peak in the (011) plane of the MoO ₂ phase, and the peak P1 corresponds to the diffraction peak in the (311) plane of the Fe ₃ O ₄ phase.

In the invention material A of FIG. 3 and the invention material B of FIG. 4, the intensity (cps) of the peak P3 is 1.5% or more of the intensity of the peak P2, and 1.5 of the intensity of the peak P1. %, The above first condition is sufficiently satisfied, and 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. Thus, it can be seen that the second condition is also satisfied.
On the other hand, in the comparative material substantially not including the complex oxide shown in FIG. 5, the intensity of the peak P3 is less than 1.5% of the intensity of the peak P2, and 1 of the intensity of the peak P1. It is less than 5% and does not satisfy the first condition.

According to experiments by the present inventors, when a sputtering target material containing Fe, Mo, (In) is produced by a high-temperature sintering method such as hot pressing, the complex compound in the target material is Fe ₂ Mo. It has been confirmed that ₃ O ₈ phase is preferentially generated. In some cases, in addition to the Fe ₂ Mo ₃ O ₈ phase, an FeMoO ₄ phase may be produced, but the absolute amount of the FeMoO ₄ phase is usually smaller than the absolute amount of the Fe ₂ Mo ₃ O ₈ phase. It has been confirmed that. Therefore, it is considered that the presence or absence of the complex oxide in the target material should be examined only for the Fe ₂ Mo ₃ O ₈ phase. Therefore, the preferable condition of the abundance ratio of the composite oxide is defined only by the intensity of the diffraction peak for the (002) plane of the Fe ₂ Mo ₃ O ₈ phase by XRD.

  The grain size (crystal grain size) in the cross-sectional structure of the target material 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 material as described above can effectively suppress the occurrence of cracks due to temperature changes during the production or sputtering film formation using the material, and thus improve the yield. At the same time, productivity can be improved. And in the sputtering target material of the aspect which contains In as a metal component, generation | occurrence | production of curvature can also be suppressed effectively, For that reason, a yield and productivity can be improved further.

〔Production method〕
Next, a method for producing the sputtering target material of the present invention will be described.
In producing the sputtering target of the present invention, the oxide powder of each metal component is mixed, and the mixed powder is sintered at a high temperature, particularly at a temperature in the range of 840 to 950 ° C. It is preferable to use the body as a target material. For example, Fe ₃ O ₄ powder is prepared as the Fe oxide powder, MoO ₂ powder is prepared as the Mo oxide powder, and In ₂ O ₃ powder is prepared as the In oxide powder, and these are mixed so as to have a predetermined metal component ratio. However, it is desirable to perform high-temperature sintering while applying pressure by a so-called hot press method.

Here, according to the experiments by the present inventors, the purpose is merely to obtain a sintered body structure in which an oxide phase of Fe alone and an oxide phase of Mo alone (and also an oxide phase of In alone) are mixed. If so, a sintering temperature of about 700 to 800 ° C is sufficient, but in order to form a composite oxide phase as described above, it is appropriate to sinter at a high temperature of 840 ° C or higher. I found it.
That is, by sintering at a high temperature of 840 ° C. or higher, as already described, between Fe oxide powder particles and Mo oxide powder particles (and In oxide powder particles) in contact with each other, Fe, Mo , (In), O interdiffusion (solid diffusion) proceeds, and as a result, it is presumed that a Fe—Mo (—In) based composite oxide is generated.

  If the heating temperature at the time of sintering is less than 840 ° C., the composite oxide is not sufficiently formed. On the other hand, if it exceeds 950 ° C., there arises a problem that DC sputtering becomes difficult due to high resistance. Therefore, it is appropriate that the sintering temperature is in the range of 840 to 950 ° C.

Moreover, although the pressure in the case of pressure-sintering by a hot press is not specifically limited, Usually, it is preferable to set it as about 100-500 kgf / cm < ² >. Further, the sintering time (retention time within the above temperature range) is not particularly limited, but usually it may be maintained for 2 to 5 hours.

  Further, the particle diameter of each oxide powder constituting the mixed powder to be subjected to sintering is not particularly limited, but usually it may be about 0.2 to 7 μm in median diameter (d50 value).

  If the target material obtained as described above is processed into a predetermined shape and a predetermined dimension by machining or the like as appropriate, and is attached to a backing plate made of copper or the like as required, the sputtering film is finally formed. It can be set as the sputtering target used for.

[Optical function film]
If a sputtering target using the target material of the present invention as described above is used to form a sputtering film on a substrate such as a metal thin film, an optical functional film is generated. The composition of this optical functional film is almost the same as the composition of the sputtering target as described above. In other words, the optical functional film contains Fe, Mo, and further In as metal elements, and part or all of the metal elements are present in the form of oxides.

  And especially if the content of Fe as a metal element in the total metal component in the sputtering target material is 20 to 95 at% and the content of Mo as a metal element is 5 to 80 at%, the optical functional film is Of the metal components, the content of Fe as a metal element is approximately 20 to 95 at%, and the content of Mo as a metal element is approximately 5 to 80 at%. Furthermore, if the sputtering target material contains In as a metal element and the content of In among all metal components is 0.1 to 23 at%, the optical functional film also contains In as the metal element. In addition, the content of In as a metal element in the total metal component is approximately 0.1 to 23 at%.

In such an optical functional film, the average reflectance can be 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. high. Therefore, it is effective as an optical functional film having an effect of concealing the metallic luster of the metal thin film by forming the film on the metal thin film (for example, the wiring pattern of the touch panel).
Furthermore, the etching property is good, and at the same time, the chemical resistance and the weather resistance are good, and the reliability and stability after etching are also good at the time of etching. Therefore, for example, as described above, a metal thin film (for example, touch panel wiring) It can be effectively applied in applications where a film is formed on a pattern) and etched.

  Examples of the present invention will be described below together with comparative examples. The following examples are for explaining the effects of the present invention, and it goes without saying that the configurations, processes, and conditions described in the examples do not limit the technical scope of the present invention.

[Manufacture of sputtering target]
A MoO ₂ powder with a median diameter (d50 value) of 4 μm, an In ₂ O ₃ powder with a median diameter of 1 μm, and an Fe ₃ O ₄ powder with a median diameter of 1 μm are prepared. In some examples, MoO ₂ powder and Fe ₃ O ₄ powder was mixed with MoO ₂ powder, Fe ₃ O ₄ powder, and In ₂ O ₃ powder in another example to prepare a mixed powder. That is, each powder was weighed so that Mo, Fe, and In as metal components had the composition ratios shown in Comparative Examples 1 to 3 and Examples 1 to 18 in Table 1, and each powder was mounted on a ball mill as a mixing device. And mixed.
Each obtained mixed powder was subjected to hot pressing at various temperatures within a range of 700 to 1000 ° C. under a pressure of 200 kgf / cm ² for 3 hours in a vacuum, and a sintered body (sputtering target material) and did.
Each obtained sintered body was machined to a diameter of 152.4 mm and a pressure of 6 mm, and then pasted to a Cu backing plate using In solder to obtain a sputtering target.

[Deposition by sputtering = Production of optical functional film]
Using such a sputtering target, an experiment was performed in which an optical functional film was formed by sputtering film formation on a glass substrate.
The film formation conditions by sputtering are as follows.
・ Power supply: DC power supply ・ Power: 600W
・ Gas pressure: Ar = 50sccm
-TS distance (target-substrate distance): 70 mm
・ Substrate temperature: Room temperature ・ Substrate: Glass substrate (Product name: Eagle XG)

  About the sintered compact (sputtering target material) obtained by high-temperature sintering as mentioned above, the presence or absence of the complex oxide (Fe—Mo—O-based compound) is examined, and the evaluation of the sputtering target material and the sputtering film formation are performed. The subsequent evaluation as an optical functional film was performed as follows, and the results are shown in Tables 1 and 2.

[Presence / absence of composite oxide (Fe-Mo-O compound)]
About each sputtering target material, the presence or absence of complex oxide (Fe-Mo-O type compound) was investigated by XRD. XRD conditions were performed by a powder method using Cu-Kα rays as X-rays.
Here, as already described, when a sputtering target material containing Fe, Mo, (In) is produced by a high temperature sintering method such as hot pressing, the composite compound in the target material is Fe ₂ Mo ₃ O _8. It has been confirmed that phases are preferentially generated. In addition to the Fe ₂ Mo ₃ O ₈ phase, an FeMoO ₄ phase may be produced, but the absolute amount of the FeMoO ₄ phase is confirmed to be smaller 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 material is determined by examining the intensity of the diffraction peak (count per second: cps) on the (002) plane of the Fe ₂ Mo ₃ O ₈ phase, and the intensity is MoO ₂ phase. The composite oxide exists when the intensity of the diffraction peak in the (011) plane is 1.5% or more or 1.5% or more of the diffraction peak intensity in the (311) plane of the Fe ₃ O ₄ phase. Therefore, “Yes” is described in the “Presence / absence of composite oxide” column of Table 1, and is less than 1.5% of the intensity of the diffraction peak in the (011) plane of the MoO ₂ phase, and Fe ₃ O _4. When the intensity of the diffraction peak at the (311) plane of the phase is less than 1.5%, it is determined that the composite oxide does not exist, and “None” is displayed in the “Presence of composite oxide” column of Table 1. Described.
In each comparative example and each example, the intensity of the diffraction peak in the (002) plane of the Fe ₂ Mo ₃ O ₈ phase is 300% or less of the intensity of the diffraction peak in the (011) plane of the MoO ₂ phase, and It was 300% or less of the intensity of the diffraction peak in the (311) plane of the Fe ₃ O ₄ phase.

[Evaluation of sputtering target material]
<Evaluation of crack occurrence>
The occurrence of cracks in the sputtering target material was examined as follows.
That is, after sintering, the target material before processing is examined by a penetrant flaw detection test, the occurrence of cracks is evaluated, and when the indication pattern is detected visually, “Yes” is displayed in the “crack” column of Table 1. It was described.
<Evaluation of warpage occurrence>
In addition, the occurrence of warpage of the target material was examined as follows.
That is, after the sintering, the warpage amount of the target material before processing was examined with a straight edge and a gap gauge. If the warp amount is 0.5 mm or less, there is no particular problem in processing, so it is determined that there is no warp. On the other hand, if the warp amount exceeds 0.5 mm, the machining allowance increases and the yield increases. Since it became worse, it was determined that there was a warp.
<Density ratio and electrical resistance evaluation>
The target material was examined for density ratio and electrical resistance. The density ratio was determined by measuring the size and weight and determining the ratio to the true density (100%). The electric resistance value was measured using a four-point probe method. In addition, Mitsubishi Chemical resistance measuring instrument Loresta GP was used for the measurement of the electrical resistance value.

[Evaluation as optical functional film]
Further, for each of the optical functional films (laminated films) laminated on the metal thin film by sputtering film formation using each of the sputtering targets of Examples 1 to 18 and Comparative Examples 1 to 3, the average reflectance and before and after the constant temperature and humidity test The maximum value of the change in reflectance at was measured as follows.
<Measurement of average reflectance>
Sputtering film formation was performed under the same conditions as described above. On the glass substrate, the thickness is 50nm.
The oxide film (optical function film) and a metal film of copper, aluminum, silver or molybdenum having a thickness of 200 nm were stacked in this order. In Example 16, Al was used, Ag was used in Example 17, Mo was used in Example 18, and Cu was used in the other Examples and Comparative Examples to form a metal film. The metal film is for metal wiring, and each metal sputtering target was used for the film formation.
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 with 4 samples produced similarly, averaged the obtained measured value, calculated | required the average reflectance, and set it as "the average reflectance (%) of a film | membrane" in Table 2.

<Measurement of maximum reflectance change>
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%
-Holding time: 250 hours After this constant temperature and humidity test, the reflectance in the wavelength range of 400 to 800 nm was measured by the same method as described above to obtain the reflectance after the test. On the other hand, the reflectance measurement value similar to the above before the constant temperature and humidity test is taken as the reflectance before the test, and the reflection at each wavelength of 400, 500, 600, 700, and 800 nm before and after the constant temperature and humidity test. The rate change was calculated. Among the above five wavelengths, the maximum value of the reflectance change was set as the “maximum reflectance change value” shown in Table 2.

  As shown in Table 1, in the sputtering target materials of Comparative Examples 1 to 3 manufactured under conditions where the sintering temperature is lower than 840 ° C., a composite oxide (Fe—Mo—O-based compound) is not substantially generated, As a result, it was confirmed that the target material was cracked.

  On the other hand, in the sputtering target materials of Examples 1 to 18 manufactured under conditions where the sintering temperature is higher than 840 ° C., as shown in Table 1, formation of complex oxide (Fe—Mo—O-based compound) is recognized. As a result, it was confirmed that no cracks occurred in the target material. However, in the sputtering target material of Example 4 manufactured under conditions where the sintering temperature was higher than 1000 ° C., the density ratio was low and the resistance value was high.

  Further, among the sputtering target materials of Examples 1 to 18, Examples 1 to 4 are examples in which In was not contained as a metal element, and Example 5 contained In, but the content was 0. In this example, the amount was less than 1 at%, and in Examples 1 to 5, warpage occurred. On the other hand, generation | occurrence | production of curvature was able to be suppressed in Examples 6-9 containing 0.1 at% or more of In. However, in Example 9, since In exceeded 23 at%, the density ratio was slightly lower.

  Examples 10 to 13 are examples in which the ratio of Mo and Fe was changed without containing In. Among these Examples 10 to 13, Fe was 20 to 95 at%, and Mo was 5 to 80 at%. In Examples 11 and 12 within the above range, there was no particular problem, but in Example 10 where Mo is less than 5 at% and Fe is more than 95 at%, the average reflectivity exceeds 30% as a film after sputtering film formation. It was. On the other hand, in Example 13 in which Mo is more than 80 at% and Fe is less than 20 at%, the maximum reflectance change amount exceeds 15% as a film after sputtering film formation.

  Further, Examples 14 and 15 are examples in which In was contained, and at the same time, the ratio of Fe and Mo was set to the upper limit or the lower limit in the above range, and good characteristics were ensured in these examples.

DESCRIPTION OF SYMBOLS 1 Mo oxide phase area | region 2 Fe oxide phase area | region 3 Fe-Mo type complex oxide phase (Fe-Mo-O type compound phase)

Claims (8)

The metal component is composed of Fe and Mo, and part or all of the metal element is present in the form of an oxide, and the oxide phase contains a Fe—Mo—O-based compound. Sputtering target material. In the sputtering target material according to claim 1,
Sputtering target material characterized in that the content of Fe as a metal element of all metal components is 20 to 95 at%, and the content of Mo as a metal element is 5 to 80 at%. In the sputtering target material according to any one of claims 1 and 2,
A sputtering target material further containing In as a metal element. In the sputtering target material according to claim 3,
Sputtering target material characterized in that the content of In as a metal element among all metal components is 0.1 to 23 at%. In the sputtering target material according to any one of claims 1 to 4,
The sputtering target material, wherein the Fe—Mo—O-based compound mainly comprises an Fe ₂ Mo ₃ O ₈ phase. In the sputtering target material according to claim 5,
The intensity of the diffraction peak in the (002) plane of the Fe ₂ Mo ₃ O ₈ phase is 1.5% or more of the intensity of the diffraction peak in the (011) plane of the MoO ₂ phase, or the (311) plane of the Fe ₃ O ₄ phase. The intensity of the diffraction peak in the (311) plane of the Fe ₃ O ₄ phase is 1.5% or more of the intensity of the diffraction peak in and 300% or less of the intensity of the diffraction peak in the (011) plane of the MoO ₂ phase. Sputtering target material characterized by being 300% or less. A method for producing the sputtering target material according to claim 1,
Sintering a mixed powder of Fe oxide powder and Mo oxide powder or a mixed powder of Fe oxide powder, Mo oxide powder and In oxide powder at a temperature in the range of 840 to 950 ° C. A method for producing a sputtering target material characterized by   An optical functional film made of an oxide formed by sputtering adjacent to a metal thin film using the sputtering target material according to any one of claims 1 to 6, wherein the metal film in the optical functional film is formed on the metal film. An optical functional film, wherein an average light reflectance measured from a non-adjacent side is 30% or less.

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