JP2020033583A - Sputtering target and method for manufacturing the same - Google Patents

Abstract

To provide a sputtering target having a sufficiently high density ratio and capable of stably depositing an oxide film by sputtering, and a method for manufacturing the sputtering target.SOLUTION: The sputtering target including Cu and In as a metal component and consisting of a composite structure between a metal phase and an oxide phase has 5% or more and 96% or less of an area ratio of the oxide phase and 90% or more of a density ratio and comprises a metal powder consisting of one or both of Cu powder and In-Cu alloy powder and an oxide powder consisting of one or both of CuO powder and InOpowder. The method for manufacturing the sputtering target comprises: the sintering raw material powder formation step of obtaining a sintering raw material powder in which the ratio D/Dof the median diameter Dof the metal powder to the median diameter Dof the oxide powder is 0.5 or more and 200 or less; and the sintering step of pressing the sintering raw material powder and heating the compact to a temperature of less than 1000°C to obtain a sintered body.SELECTED DRAWING: None

Description

  The present invention relates to a sputtering target used for forming an oxide film, and a method for manufacturing the sputtering target.

2. Description of the Related Art In recent years, a projection-type capacitive touch panel has been employed as an input unit of a portable terminal device or the like. In this type of touch panel, sensing electrodes are formed for touch position detection. This sensing electrode is usually formed by patterning, and an X electrode extending in the X direction and a Y electrode extending in the Y direction orthogonal to the X direction are formed on one surface of the transparent substrate. And these are arranged in a grid.
Here, when a metal film is used for the electrode of the touch panel, the pattern of the electrode is visually recognized from the outside because the metal film has a metallic luster. For this reason, it is conceivable that the visibility of the electrode is reduced by forming a low-reflectance film having a low visible light reflectance on the metal thin film.

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

Further, in a solar cell panel, when sunlight is incident through a glass substrate or the like, a back electrode of the solar cell is formed on the opposite side. 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, the metal film as the back surface electrode is visually recognized.
Therefore, it is conceivable that the visibility of the back electrode is reduced by forming the above-described low reflectance film on the back electrode.

Therefore, for example, Patent Literatures 1 and 2 propose an oxide film suitable as the above-described low reflectance film and a sputtering target used for forming the oxide film.
In the sputtering target described in Patent Document 1, as a metal element, one or two of Mo and In and one or two of Cu and Fe are used as main components, and these metal elements are used. Is partially or entirely made of an oxide.
Further, the sputtering target described in Patent Document 2 contains Fe and Mo as metal elements, and some or all of these metal elements exist in the form of oxides, and the oxide phase contains Fe-Mo. It is assumed that a -O-based compound is included.

JP-A-2006-027195 JP-A-2006-191090

By the way, in the above-mentioned sputtering target, when the density ratio is low, vacancies are formed inside, and abnormal discharge is likely to occur during sputtering film formation.
Here, in the sputtering target for forming the above-described oxide film, if the sintering temperature is set high to improve the density ratio, the oxide powder is reduced, and the sputtering target after sintering is reduced. May not be stable. On the other hand, when the pressing load is increased to improve the density ratio, there is a problem that a sputtering target made of an oxide is cracked and the production yield is reduced.
As described above, in the sputtering target for forming an oxide film, it is difficult to sufficiently improve the density ratio because the melting point of the oxide powder is high and the sinterability is insufficient. Was.

In particular, in recent years, from the viewpoint of improving production efficiency, it has been required to further increase the power density ratio at the time of sputter deposition to further improve the deposition throughput, and abnormal discharge tends to occur.
In addition, a large sputtering target or a cylindrical sputtering target is required to cope with an increase in the size of a substrate on which a film is formed and an improvement in film formation efficiency, and it is more difficult to improve a density ratio.
For this reason, in a sputtering target for forming the above oxide film, further improvement in the density ratio is required.

  The present invention has been made in view of the circumstances described above, and provides a sputtering target having a sufficiently high density ratio, capable of stably forming an oxide film by sputtering, and a method of manufacturing the sputtering target. The purpose is to do.

  In order to solve the above problems, a sputtering target of the present invention contains Cu and In as metal components, has a composite structure of a metal phase and an oxide phase, and has an area ratio of the oxide phase of 5% or more. It is characterized by being within a range of 96% or less and a density ratio of 90% or more.

According to the sputtering target having this configuration, Cu and In are contained as metal components, and the composite target has a composite structure of a metal phase and an oxide phase. Therefore, an oxide film containing Cu and In as metal components is formed by sputtering. It becomes possible to film.
Further, since the density ratio is set to 90% or more, it is possible to suppress occurrence of abnormal discharge caused by holes.
Further, since the area ratio of the oxide phase is in the range of 5% or more and 96% or less, the areas of the metal phase and the oxide phase are secured, and the discharge state is stabilized on the entire target sputtering surface. In addition, occurrence of abnormal discharge can be suppressed.

Here, in the sputtering target of the present invention, it is preferable that the content of Cu in the metal component is in the range of 10 at% to 90 at%.
In this case, an oxide film having a composition in which the content of Cu in the metal component is in the range of 10 atomic% to 90 atomic% can be formed, the visible light reflectance is low, and the low reflectance is low. An oxide film that can be used as a film can be reliably formed.

Further, the sputtering target of the present invention may have a structure in which the metal phase is dispersed in a matrix composed of the oxide phase, and the average particle diameter of the metal phase is 56 μm or less.
In this case, since the average particle size of the metal phase dispersed in the matrix composed of the oxide phase is limited to 56 μm or less, the metal phase is not locally aggregated, and the discharge state is generated on the entire target sputtering surface. And the occurrence of abnormal discharge can be further suppressed.

Further, the sputtering target of the present invention may have a structure in which the oxide phase is dispersed in a matrix composed of the metal phase, and the average crystal particle diameter in the metal phase is 100 μm or less.
In this case, the structure is such that the oxide phase is dispersed in the parent phase composed of the metal phase, and the average crystal grain size in the parent metal phase is limited to 100 μm or less. Generation can be suppressed, and manufacturing yield can be improved. In addition, even if the sputtering proceeds, no large irregularities are formed on the target sputtering surface, the occurrence of abnormal discharge can be suppressed, and the sputtering film can be stably formed.

The method for manufacturing a sputtering target of the present invention is a method for manufacturing a sputtering target for manufacturing the above-described sputtering target, and includes a metal powder composed of one or both of a Cu powder and a Cu-In alloy powder, a CuO powder and an In powder. _An oxide powder composed of one or both of ₂ O ₃ powders, and a ratio D _M / D _O of the median diameter D _{M of the} metal powder to the median diameter D _O of the oxide powder is 0.1. A sintering raw material powder forming step of obtaining a sintering raw material powder within a range of 5 to 200, and sintering of pressing and heating the sintering raw material powder to a temperature of less than 1000 ° C. to obtain a sintered body And a process.

According to the method for manufacturing a sputtering target having this configuration, a metal powder composed of one or both of a Cu powder and a Cu—In alloy powder, and an oxide composed of one or both of a CuO powder and an In ₂ O ₃ powder And a ratio of the median diameter D _{M of the} metal powder to the median diameter D _O of the oxide powder D _M / D _O is in the range of 0.5 to 200. Since sintering is used, voids are eliminated by sintering, filling voids between oxide powders while deforming a ductile metal phase, thereby reliably improving the density ratio. Can be.
In addition, since a sintering step of obtaining a sintered body by pressing the sintering raw material powder and heating it to a temperature of less than 1000 ° C. is provided, the sintering temperature is relatively low, and reduction of oxide powder is suppressed. can do.

Here, in the method for manufacturing a sputtering target of the present invention, the oxide powder preferably has a median diameter D _O of 5 μm or less.
In this case, since the median diameter D _O of the oxide powder is relatively fine, that is, 5 μm or less, the contact area between the oxide powders increases, the sinterability can be improved, and the density ratio can be improved. It is possible to further improve.

  According to the present invention, it is possible to provide a sputtering target having a sufficiently high density ratio and capable of stably forming an oxide film by sputtering, and a method for manufacturing the sputtering target.

FIG. 3 is an explanatory view showing a structure in which a metal phase is dispersed in a matrix composed of an oxide phase in the sputtering target according to one embodiment of the present invention. FIG. 3 is an explanatory view showing a structure in which an oxide phase is dispersed in a parent phase composed of a metal phase in the sputtering target according to one embodiment of the present invention. It is a flow figure showing the manufacturing method of the sputtering target concerning one embodiment of the present invention.

  Hereinafter, a sputtering target according to an embodiment of the present invention and a method for manufacturing the sputtering target will be described with reference to the accompanying drawings.

The sputtering target according to the present embodiment contains Cu and In as metal components and has a composite structure of a metal phase and an oxide phase.
The area ratio of the oxide phase is in the range of 5% or more and 96% or less, and the density ratio is 90% or more.
In the present embodiment, it is preferable that the content of Cu in the metal component is in the range of 10 at% to 90 at%.

  Here, in the sputtering target according to the present embodiment, as described above, the area ratio of the oxide phase is in the range of 5% or more and 96% or less, and when the ratio of the oxide phase is high, When the ratio of the metal phase is high, the structure is such that the oxide phase is dispersed in the metal phase.

FIG. 1 is an example of a structure in which the metal phase is dispersed in a matrix composed of an oxide phase, and is a structure in which a metal phase 12 is dispersed in a matrix composed of an oxide phase 11. In the case of such a structure, the average particle size of the dispersed metal phase 12 (that is, the size of the dispersed metal phase 12 itself) is preferably 56 μm or less.
FIG. 2 is an actual example of a structure in which an oxide phase is dispersed in a matrix composed of a metal phase, and is a structure in which an oxide phase 11 is dispersed in a matrix composed of a metal phase 12. In the case of such a structure, it is preferable that the average crystal grain size in the metal phase 12, which is the parent phase, be 100 μm or less.

  Hereinafter, in the sputtering target of the present embodiment, the area ratio of the oxide phase, the density ratio, the content of Cu in the metal component, the average particle diameter of the dispersed metal phase, the average crystal particles in the metal phase that is the parent phase The reason for defining the diameter as described above will be described.

(Area ratio of oxide phase)
The sputtering target according to the present embodiment has a composite structure of a metal phase and an oxide phase, and the density ratio is improved by the metal phase.
Here, when the area ratio of the oxide phase is less than 5%, an oxide phase having a higher electric resistance than the metal phase is present in isolation, and the oxide phase causes sputtering. Sometimes abnormal discharge may occur.
On the other hand, if the area ratio of the oxide phase exceeds 96%, the metal phase may be insufficient, and the density ratio may not be sufficiently improved.
From the above, in the present embodiment, the area ratio of the oxide phase is set in the range of 5% to 96%.

Note that, in order to further suppress the occurrence of abnormal discharge due to the isolated oxide phase, the lower limit of the area ratio of the oxide phase is preferably set to 15% or more, more preferably 30% or more.
In order to further improve the density ratio, the upper limit of the area ratio of the oxide phase is preferably set to 90% or less, more preferably 85% or less.

(Density ratio)
When the density ratio of the sputtering target is low, there are many holes inside, and abnormal discharge may easily occur during sputtering film formation. In particular, in a sputtering target composed of an oxide phase, the density ratio tends to be low due to insufficient sinterability of the oxide, and abnormal discharge is likely to occur.
Therefore, in the sputtering target according to the present embodiment, the density ratio is set to 90% or more. The density ratio is preferably 92% or more, and more preferably 94% or more.
Here, the density ratio is a ratio of the actual density ratio (actually measured density ratio) to the theoretical density ratio of the sputtering target. The theoretical density ratio of the sputtering target is calculated according to the composition.

(Content of Cu in metal component)
An oxide film formed using the sputtering target of this embodiment has a composition equivalent to that of the above-described sputtering target.
Here, in the sputtering target according to the present embodiment, by setting the content of Cu in the metal component in the range of 10 atomic% to 90 atomic%, the average reflectance in visible light (wavelength 400 to 800 nm) is obtained. And the oxide film having a sufficiently low reflectance can be formed.
Note that in order to reliably form an oxide film with sufficiently low visible light reflectance, the lower limit of the Cu content in the metal component is preferably 20 atomic% or more, and more preferably 30 atomic% or more. More preferably, Further, the upper limit of the content of Cu in the metal component is preferably set to 80 atomic% or less, more preferably 70 atomic% or less.

(Average particle size of dispersed metal phase)
In a sputtering target having a structure in which a metal phase is dispersed in a matrix composed of an oxide phase, by reducing the average particle diameter of the dispersed metal phase, there is no locally low electric resistance portion, and the target sputtering is performed. The discharge state is stabilized on the entire surface, and it is possible to suppress occurrence of abnormal discharge during sputtering film formation.
Therefore, when the sputtering target of the present embodiment has a structure in which the metal phase is dispersed in the matrix composed of the oxide phase, it is preferable to limit the average particle diameter of the dispersed metal phase to 56 μm or less.
The average particle diameter of the dispersed metal phase is preferably 45 μm or less, and more preferably 35 μm or less.

(Average crystal particle diameter in the metal phase which is the parent phase)
In a sputtering target having a structure in which an oxide phase is dispersed in a parent phase composed of a metal phase, by reducing the average crystal grain size in the parent metal phase, when sputtering proceeds, the parent phase of the metal phase is reduced. Large irregularities are suppressed, and the occurrence of abnormal discharge can be suppressed. Further, it is possible to suppress the flatness of the metal phase from being crushed due to the collapse of the ductile metal phase, to suppress the occurrence of cracks when processing the sintered body to produce a sputtering target, and to improve the production yield. be able to.
Therefore, when the sputtering target of the present embodiment has a structure in which an oxide phase is dispersed in a parent phase composed of a metal phase, the average crystal grain size in the parent metal phase is limited to 100 μm or less. Is preferred.
The average crystal particle diameter in the metal phase as the parent phase is preferably 75 μm or less, more preferably 50 μm or less.

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

(Sintering raw material powder forming step S01)
First, a metal powder consisting of one or both of Cu powder and an In-Cu alloy powder, the oxide powder consisting of either one or both of the CuO powder and In ₂ O ₃ powder, prepared.
Here, the purity of the Cu powder is preferably 99.99 mass% or more.
Further, as for the In-Cu alloy powder, it is preferable to use one having a composition in which the content of Cu is in the range of 5 mass% to 50 mass% and the balance is In and inevitable impurities.
The CuO powder preferably has a purity of 99 mass% or more.
The In ₂ O ₃ powder preferably has a purity of 99 mass% or more.

As for the particle diameters of the metal powder and the oxide powder, the ratio D _M / D _O between the median diameter D _M of the metal powder and the median diameter D _O of the oxide powder is in the range of 0.5 to 200. Adjust to be inside.
In the present embodiment, the median diameter D _O of the oxide powder is preferably 5 μm or less.

Here, when Cu powder and In-Cu alloy powder are included as the metal powder, the median diameter D _M of the metal powder is the median diameter D _Cu of the Cu powder, the median diameter D _InCu of the In-Cu alloy powder, and the metal powder. It is calculated as follows from the mass ratio W _Cu of the Cu powder in the metal and the mass ratio W _InCu of the In-Cu alloy powder in the metal powder.
D _M = (D _Cu × W _Cu + D _InCu × W _InCu )

Also, when containing a CuO powder and _In 2 _{O 3} powder as an oxide powder, median diameter _{D O} of the oxide powder, the median diameter _{D In2 O3} median diameter _{D CuO} and _In 2 _{O 3} powder CuO powder oxide It is calculated as follows from the mass ratio W _CuO of the CuO powder in the material powder and the mass ratio W _In2O3 of the In ₂ O ₃ powder in the oxide powder.
D _O = (D _CuO × W _CuO + D _In2O3 × W _In2O3 )

The above-mentioned metal powder and oxide powder are mixed at a predetermined ratio to obtain a sintering raw material powder.
Here, in the sintering raw material powder forming step S01, it is preferable to use a mixing device such as a ball mill.

(Sintering step S02)
Next, the above-mentioned sintering raw material powder is sintered by heating while applying pressure to obtain a sintered body. In this embodiment, a hot press is used.
In the sintering step S02, the voids between the oxide powders are filled with a ductile metal phase while being deformed, thereby eliminating the voids and improving the density ratio.
The sintering temperature in the sintering step S02 is lower than 1000 ° C., the holding time at the sintering temperature is within a range of 0.5 to 10 hours, and the pressurizing pressure is within a range of 5 to 50 MPa.

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

Hereinafter, the manufacturing method of a sputtering target which is the present embodiment, the ratio D _{M /} D O of the median diameter D _O of the median diameter D _M of the metallic powder oxide _powder, median diameter D _O of the oxide _powder, baked The reason why the stipulation condition is defined as described above will be described.

(Ratio D _M / D _O between median diameter D _{M of} metal powder and median diameter D _O of oxide powder)
In this embodiment, a sintered body is manufactured by pressing and heating a sintering raw material powder obtained by mixing a metal powder and an oxide powder.
Here, when the ratio D _M / D _O between the median diameter D _M of the metal powder and the median diameter D _O of the oxide powder is less than 0.5, the voids between the oxide powders are fine metal. Therefore, in the sintering step S02, the voids between the oxide powders cannot be filled while the ductile metal phase is deformed, and the voids can be efficiently eliminated. And the density ratio may not be improved.
On the other hand, when the median diameter ratio D _M / D _O exceeds 200, the number of oxide powders in contact with the metal powders is small, and the voids between the oxide powders cannot be sufficiently filled with the metal phase, and the density is low. There is a possibility that the ratio cannot be improved.
From the above, in the present embodiment, the ratio D _M / D _O between the median diameter D _M of the metal powder and the median diameter D _O of the oxide powder is set in the range of 0.5 to 200. .

The upper limit of the ratio D _M / D _O between the median diameter D _M of the metal powder and the median diameter D _O of the oxide powder is preferably 150 or less, and more preferably 100 or less.

(Median diameter D _O of oxide powder)
By reducing the median diameter D _O of the oxide powder in the sintering raw material powder, the sinterability is improved, and the density ratio can be sufficiently improved.
Therefore, in this embodiment, the median diameter D _O of the oxide powder is preferably 5 μm or less, more preferably 3 μm or less.

(Sintering conditions)
In the present embodiment, the sintering temperature is less than 1000 ° C. Thereby, in the sintering step S02, reduction of the oxide powder can be suppressed, and a sputtering target having a predetermined composition and structure can be manufactured.
The upper limit of the sintering temperature is preferably lower than 980 ° C, more preferably lower than 950 ° C. On the other hand, the lower limit of the sintering temperature is preferably 800 ° C. or higher, more preferably 850 ° C. or higher.

By setting the holding time at the sintering temperature in the range of 0.5 hours or more and 10 hours or less, sintering can be reliably advanced.
The lower limit of the holding time at the sintering temperature is preferably at least 1 hour, more preferably at least 2 hours. On the other hand, the upper limit of the holding time at the sintering temperature is preferably 8 hours or less, and more preferably 6 hours or less.

Further, by setting the applied pressure within the range of 5 MPa or more and 50 MPa or less, the density ratio can be sufficiently improved.
Note that the lower limit of the pressure is preferably 10 MPa or more, and more preferably 15 MPa or more. On the other hand, the upper limit of the pressurizing pressure is preferably at most 48 MPa, more preferably at most 45 MPa.

According to the sputtering target of the present embodiment configured as described above, since the density ratio is set to 90% or more, it is possible to suppress occurrence of abnormal discharge due to holes.
Further, since the area ratio of the oxide phase is in the range of 5% or more and 96% or less, the areas of the metal phase and the oxide phase are secured, and the discharge state is stabilized on the entire target sputtering surface. The occurrence of abnormal discharge can be suppressed.

Furthermore, since it contains Cu and In as metal components and has a composite structure of a metal phase and an oxide phase, it becomes possible to form an oxide film containing Cu and In as metal components by sputtering. .
In the present embodiment, when the content of Cu in the metal component is in the range of 10 atomic% to 90 atomic%, an oxide film having the above composition can be formed, The reflectance of visible light is low, and an oxide film suitable for a low reflectance film can be reliably formed.

  Further, in the sputtering target of the present embodiment, the structure is such that a metal phase is dispersed in a matrix composed of an oxide phase, and when the average particle diameter of the metal phase is 56 μm or less, the metal phase is locally It is not agglomerated, the discharge state is stable on the entire target sputter surface, and the occurrence of abnormal discharge during sputter film formation can be suppressed, and the sputter film can be stably formed.

  Alternatively, the sputtering target of the present embodiment has a structure in which an oxide phase is dispersed in a parent phase composed of a metal phase, and when the average crystal grain size in the parent metal phase is 100 μm or less, the sputtering target The generation of large irregularities in the parent phase of the metal phase when the gas progresses can be suppressed, and the occurrence of abnormal discharge can be suppressed. In addition, workability is improved, generation of cracks when processing a sintered body to produce a sputtering target can be suppressed, and production yield can be improved.

According to the method for manufacturing a sputtering target according to the present embodiment, a metal powder composed of one or both of a Cu powder and a Cu—In alloy powder, and a metal powder composed of one or both of a CuO powder and an In ₂ O ₃ powder. Oxide powder; and a sintering raw material powder in which the ratio D _M / D _O between the median diameter D _M of the metal powder and the median diameter D _O of the oxide powder is in the range of 0.5 to 200. Is used, the ductile metal phase deforms and fills the voids between the oxide powders during sintering, eliminating pores during sintering and ensuring a density ratio. Can be improved.

  In addition, in the sintering step S02, the sintering raw material powder is heated to a temperature of less than 1000 ° C. while being pressed, so that the sintering temperature can be relatively low, and reduction of the oxide powder can be suppressed. Can be. Further, since the above-mentioned sintering raw material powder is used, even if the sintering temperature is lower than 1000 ° C., the density ratio can be sufficiently improved.

Further, in the present embodiment, when the median diameter D _O of the oxide powder is set to 5 μm or less, the contact area between the oxide powders increases, the sinterability can be improved, and the density ratio can be further improved. It is possible to do.

  As described above, the embodiments of the present invention have been described, but the present invention is not limited thereto, and can be appropriately changed without departing from the technical idea of the present invention.

  Hereinafter, the results of an evaluation test for evaluating the effects of the sputtering target according to the present invention and the method for manufacturing the sputtering target will be described.

A metal powder (Cu has a purity of 99.99% by mass or more) and an oxide powder (all have a purity of 99% by mass or more) shown in Table 1 are prepared, and a total of 2 kg is weighed so as to have a compounding amount shown in Table 1, respectively. And 6 kg of the zirconia balls were charged into a ball mill container and mixed using a ball mill to obtain a sintering raw material powder.
In addition, the median diameter D _M of the metal powder and the median diameter D _O of the oxide powder were calculated using the formulas described in the section of the embodiment.

Then, the obtained sintering raw material powder is filled in a carbon mold for hot pressing, the sintering temperature is 950 ° C., the holding time at the sintering temperature is 3 hours, and the pressing pressure is 35 MPa. Was performed to obtain a sintered body.
Then, the obtained sintered body was machined to a size of 152.4 mm in diameter and 6 mm in thickness. This was soldered to a backing plate using an In solder material.

  For the obtained sputtering target, the density ratio, the metal component in the sputtering target, the area ratio of the oxide phase, the average particle diameter of the metal phase when the parent phase is an oxide phase, and the metal phase when the parent phase is a metal phase The average crystal grain size, the occurrence of cracks during processing, the number of abnormal discharges during sputtering film formation, and the reflectance of the formed oxide film were evaluated as follows.

(Density ratio)
A sample having a size of 10 mm × 10 mm × 5 mm was collected from the sputtering target, the cut surface was polished, and three composition images were photographed at 3000 times magnification using an electron probe microanalyzer (EPMA). The area ratio of the ratio of the pores observed in black in the composition image to the other portions was calculated using image analysis software WinRoof (manufactured by Mitani Corporation). The average value of the results for the three images is shown in the table, with the ratio of the portions other than black being the density ratio.

(Metal component of sputtering target)
1 g of a measurement sample was collected from the obtained sintered body, and the metal components of Cu and In were quantified by an ICP-AES apparatus. Using the total value of the obtained metal components as the total metal component amount, the metal component value of Cu was determined according to the following equation. Further, In is the remaining part.
Cu content (atomic%) = (Cu quantitative value) / (total metal component amount) × 100

(Area ratio of oxide phase)
A sample having a size of 10 mm × 10 mm × 5 mm was collected from the obtained sintered body, the cut surface was polished, and a composition image and an element mapping image of Cu, In, and O were obtained using an electron probe microanalyzer (EPMA). , The metal phase and the oxide phase are distinguished, and the image analysis software WinRoof (manufactured by Mitani Corporation) converts the captured image into monochrome, and binarizes the image with a threshold setting in which hue, lightness, and saturation are adjusted. The area ratio of the oxide phase to the entire image was calculated.

(Average particle size of the metal phase when the parent phase is an oxide phase)
From the result of the image analysis of the 1000-fold composition image by the above-mentioned electron probe microanalyzer (EPMA) apparatus, when the parent phase was an oxide phase, the average particle diameter of the metal phase was calculated from the result of the image analysis. Calculated.

(Average crystal particle diameter in the metal phase when the mother phase is a metal phase)
From the result of image analysis of a 1000-fold composition image by the above-described electron probe microanalyzer (EPMA) apparatus, when the parent phase is a metal phase, the average crystal particle size in the metal phase is calculated from the result of the image analysis. Calculated.

(With or without cracks)
A penetrant inspection test was performed on the processed sintered body to evaluate the occurrence of cracks, and the indication pattern was visually evaluated.

(Number of abnormal discharges during sputter deposition)
Using the obtained sputtering target, sputtering was performed for 1 hour under the following conditions, and the number of abnormal discharges was measured by an arc counting function provided in the DC power supply device.
Power: DC power Power: 600W
Gas pressure: 0.2Pa
Gas flow rate: Ar, 50 sccm
Target-substrate distance: 70 mm
Substrate temperature: room temperature Substrate: glass substrate (product name: Eagle XG)

(Reflectance of oxide film)
A silver film with a thickness of 200 nm was formed over a glass substrate, and an oxide film was formed with a thickness of 50 nm over the silver film using the above-described sputtering target.
The reflectance of the stacked film of the silver film and the oxide film formed on the glass substrate as described above was measured. Using a spectrophotometer (U4100 manufactured by Hitachi, Ltd.), measurement was performed at a wavelength of 400 to 800 nm from the side of the formed film. The average value of the measured reflectance was defined as “average reflectance of the oxide film”.

In Comparative Example 1 in which the metal powder was not used and the area ratio of the oxide phase was 100%, the density ratio was as low as 81.2% and the number of abnormal discharges was as large as 125 times. In addition, cracks were observed during processing. It is presumed that the sinterability was insufficient and that many pores existed inside.
In Comparative Example 2 in which the ratio D _M / D _O between the median diameter D _M of the metal powder and the median diameter D _O of the oxide powder was 0.3, the density ratio was as low as 87.4%, and the number of abnormal discharges Increased to 64 times. It is presumed that at the time of sintering, the voids between the oxide powders could not be filled while the ductile metal phase deformed, and the voids could not be efficiently eliminated.

In Comparative Example 3 in which the ratio D _M / D _O between the median diameter D _M of the metal powder and the median diameter D _O of the oxide powder was 217, the density ratio was as low as 83.6%, and the number of abnormal discharges was 74. More times. It is presumed that the number of oxide powders in contact with the metal powder during sintering was small, and the voids between the oxide powders could not be sufficiently filled with the metal phase.
In Comparative Example 4 in which the area ratio of the oxide phase was 4.0%, the number of abnormal discharges increased to 43. It is presumed that an oxide phase having a higher electric resistance than the metal phase was present in isolation, and abnormal discharge occurred due to the oxide phase.

On the other hand, the ratio D _M / D _O between the median diameter D _M of the metal powder and the median diameter D _O of the oxide powder is in the range of 0.5 to 200, and the density ratio is 90% or more, and In Example 1-8 of the present invention in which the area ratio of the phase was in the range of 5% or more and 96% or less, the number of abnormal discharges was as small as 15 or less, and no cracking was observed during processing. In Example 9 of the present invention, the average particle diameter of the matrix metal was relatively large at 111 μm, and although cracks were observed after processing, no effect on abnormal discharge was observed. In Example 1-9 of the present invention, the average reflectance of the formed oxide film was 21% or less, and an oxide film usable as a low-reflectance film could be formed.
In addition, comparing Example 3 of the present invention with Example 7 of the present invention, it was confirmed that the occurrence of abnormal discharge can be further suppressed by setting the average particle diameter of the metal phase when the mother phase is an oxide phase to 56 μm or less. Was. In addition, in Example 8 of the present invention, the number of abnormal discharges was slightly increased because the density ratio was lower than that of the other examples of the present invention.

  From the above, it was confirmed that according to the example of the present invention, it is possible to provide a sputtering target having a sufficiently high density ratio, capable of stably forming an oxide film by sputtering, and a method of manufacturing this sputtering target. .

11 Oxide phase 12 Metal phase

Claims (6)

  It contains Cu and In as metal components, and has a composite structure of a metal phase and an oxide phase. The area ratio of the oxide phase is in the range of 5% or more and 96% or less, and the density ratio is 90% or more. A sputtering target, characterized in that:   2. The sputtering target according to claim 1, wherein the content of Cu in the metal component is in a range from 10 atomic% to 90 atomic%. 3.   3. The structure according to claim 1, wherein the metal phase has a structure in which the metal phase is dispersed in a matrix composed of the oxide phase, and the dispersed metal phase has an average particle diameter of 56 μm or less. Sputtering target.   3. A structure in which the oxide phase is dispersed in a matrix composed of the metal phase, and an average crystal grain size of the metal phase as the matrix is 100 μm or less. The sputtering target according to 1. It is a manufacturing method of the sputtering target which manufactures the sputtering target according to any one of claims 1 to 4,
A median of the metal powder, comprising a metal powder composed of one or both of Cu powder and In-Cu alloy powder, and an oxide powder composed of one or both of CuO powder and In ₂ O ₃ powder. A sintering raw material powder forming step of obtaining a sintering raw material powder in which a ratio D _M / D _O between the diameter D _M and the median diameter D _O of the oxide powder is in the range of 0.5 to 200,
A sintering step of pressing the sintering raw material powder and heating to a temperature of less than 1000 ° C. to obtain a sintered body,
A method for producing a sputtering target, comprising: The method for producing a sputtering target according to claim 5, wherein a median diameter D _O of the oxide powder is 5 µm or less.