TW201938513A - Sputtering target material and sputtering target - Google Patents

Abstract

One embodiment of the present invention is a sputtering target material which contains an oxide of zinc (Zn), an oxide of tin (Sn) and an oxide of zirconium (Zr), but does not contain indium (In), and wherein: relative to all elements other than oxygen (O), the zinc content AZn is more than 0 at% but 50 at% or less, the tin content ASn is from 20 at% to 80 at% (inclusive), and the zirconium content AZr is more than 0 at% but 40 at% or less; the Zn content AZn satisfies formula (1); the ratio of the maximum value to the minimum value among the plurality of measured specific resistances is 3 or less; and the specific resistances are 5 * 10<SP>-1</SP> ([Omega].cm) or less. (1): AZn/(AZn + ASn) ≤ 0.6.

Description

Sputtering target and sputtering target

The invention relates to a sputtering target and a sputtering target.

Optical recording media are represented by optical discs such as CDs and DVDs, and are classified into three types of reproduction-only type, write-once type, and re-write type. In addition, as a recording method of an optical recording medium, a method in which a constituent material of a recording layer undergoes a phase change, a method in which a multilayered recording layer performs an interlayer reaction, and a method in which a constituent material of a recording layer is decomposed. As a recording layer material of a write-once optical disc, an organic pigment material has been widely used until now. However, in recent years, the recording density has been increasing, and an inorganic material can also be used.

It is known that when a metal oxide is used as an inorganic material in a recording layer, information is recorded by decomposition of the oxide, but the recording layer is suppressed in order to suppress deterioration due to changes with time of the recording layer. The signal characteristics are good, and a dielectric layer is formed on the front and back of the recording layer by sputtering. A ZrO ₂ -In ₂ O ₃ based sputtering target is proposed, which is a sputtering target that forms a dielectric layer (protective layer), and makes more than 90% of the zirconium (Zr) contained in Zr and indium (In). The form of the composite oxide phase is dispersed in the sputtering target, thereby having excellent crack resistance (Japanese Patent Laid-Open No. 2009-62585). According to this sputtering target, cracks do not occur even if sputtering is performed at a high output, so that the dielectric layer can be efficiently formed, and the production efficiency of the optical recording medium is improved.

However, if sputtering is performed at a high output, abnormal discharge occurs, and the matrix of the sputtering target becomes a granular mass and scatters in the recording layer, that is, so-called particles are generated. However, the ZrO ₂ -In ₂ O ₃ system is sputtered. There is a concern that the plating target cannot effectively suppress abnormal discharge. In addition, since the conductivity of the sputtering target can be ensured by the oxide containing In, the formation speed can be increased, and the step operation time can be shortened. However, In is designated as a specific chemical substance, and it is necessary to take measures to prevent health disorders.
[Prior Art Literature]
[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2009-62585

[Problems to be Solved by the Invention]

The present invention has been made based on the above circumstances, and an object thereof is to provide a sputtering target and a sputtering target which can effectively suppress abnormal discharge when a dielectric layer of an optical recording medium is formed, and does not require a health obstacle prevention measure.
[Means for solving problems]

One embodiment of the present invention, which is made to solve the above-mentioned problems, is a sputtering target, which includes zinc (Zn) oxide, tin (Sn) oxide, and zirconium (Zr) oxide. All elements other than oxygen (O), and Zn content a _Zn is more than 0 at% and 50 at% or less, the content of a _Sn of tin is at least 20 at% and 80 at% or less, and the content a _Zr zirconium is exceeded 0 at% and 40 at% or less, and the content of zinc A _Zn satisfies the following formula (1); the ratio of the maximum value to the minimum value among a plurality of measured specific resistance values is 3 or less, and the specific resistance value It is 5 × 10 ^-1 (Ω · cm) or less; and the sputtering target does not contain indium (In).
A _Zn / (A _Zn + A _Sn ) ≦ 0.6 ･ ･ ･ ･ ･ (1)

The sputtering target is formed of an oxide of Zn, an oxide of Sn, and an oxide of Zr, and the content is within the above range. Therefore, a sputtering target capable of forming a dielectric layer having excellent characteristics can be manufactured. In addition, the ratio of the maximum value to the minimum value of the measured specific resistance values is 3 or less, and the specific resistance value is 5 × 10 ^-1 (Ω · cm) or less. Therefore, when a dielectric layer is formed by a sputtering method Can effectively suppress abnormal discharge and reduce the generation of particles. In addition, since the sputtering target does not contain In element, it is not necessary to take measures to prevent health disorders. Therefore, the production efficiency of the optical recording medium can be improved.

The sputtering target may have a SnO ₂ phase and a Zn ₂ SnO ₄ phase, and a ratio of a Zr element concentration in the Zn ₂ SnO ₄ phase to a Zr element concentration in the SnO ₂ phase is 0.1 or more and 5 or less. Thereby, a sputtering target with excellent strength can be manufactured.

The sputter target may comprise ZrO ₂ crystal grains of the ZrO ₂ crystal grains of an average particle diameter of 5 μm or less. This makes it possible to produce a sputtering target having more excellent strength.

Another embodiment of the present invention that was made to solve the above-mentioned problems is a sputtering target including the sputtering target. This sputtering target can effectively suppress an abnormal discharge when a dielectric layer is formed by a sputtering method, and thus can effectively form a dielectric layer.
[Effect of the invention]

As described above, when the sputtering target and the sputtering target of the present invention are used to form a dielectric layer of an optical recording medium, abnormal discharge can be effectively suppressed, and no health obstacle prevention measures are required.

Hereinafter, embodiments of the sputtering target and the sputtering target of the present invention will be described in detail.

[Sputter target]
A sputtering target as one embodiment of the present invention is used to form a dielectric layer on the front and back of a recording layer of an optical recording medium. The sputtering target is manufactured by using a sputtering target material, the sputtering target material including zinc (Zn) oxide, tin (Sn) oxide, and zirconium (Zr) oxide, with respect to oxygen (O All elements) other than the zinc content a _Zn more than 0 at% and 50 at% or less, the content of a _Sn of tin is at least 20 at% and 80 at% or less, and the content of zirconium is a _Zr exceeds 0 at% and 40 at% or less, and the content of zinc A _Zn satisfies the following formula (1); the ratio of the maximum value to the minimum value of the plurality of specific resistance values measured is 3 or less, and the specific resistance value is 5 × 10 ^-1 (Ω · cm) or less; and the sputtering target does not contain indium (In). The sputtering target is another embodiment of the present invention.
A _Zn / (A _Zn + A _Sn ) ≦ 0.6 ･ ･ ･ ･ ･ (1)

＜ Sputtering target ＞
This sputtering target contains respective oxides of Zn, Sn, and Zr. Since the sputtering target contains respective oxides of Zn, Sn, and Zr, the same oxide can be contained in the dielectric layer. The dielectric layer has a function of preventing the oxygen released from the recording layer from decomposing from the recording layer, a function of maintaining the durability of the recording layer, and a function of adjusting the amount of transmitted light.

Zn is an element for suppressing variations in the shape or size of a recording mark formed in the recording layer by adding it to the dielectric layer at the same time as Sn, thereby reducing jitter.

Sn is an element for providing a dielectric layer with an oxygen barrier function to prevent decomposition of the recording layer.

Zr is an element for improving the oxygen barrier function of the dielectric layer and suppressing the deterioration of the recording signal of the recording layer.

The lower limit of the content _Zn of the sputtering target with respect to all elements other than oxygen, A _Zn , exceeds 0 at%, preferably 20 at%, and more preferably 30 at%. On the other hand, the upper limit of the Zn content A _Zn is 50 at%, preferably 47 at%, and more preferably 45 at%. In the case where the sputtering target A _Zn content of Zn is less than the above lower limit, the dielectric layer has insufficient Zn oxide, the dielectric layer can not be sufficiently suppressed is formed in the shape or size of the recording mark of the recording layer Worries about deviations. On the other hand, when the Zn content A _Zn exceeds the above-mentioned upper limit, there is a concern that the content of oxides of other elements may be insufficient.

The lower limit of the content _Sn of the sputtering target with respect to all elements other than oxygen, A _Sn , is 20 at%, preferably 30 at%, and more preferably 40 at%. On the other hand, the upper limit of the Sn content A _Sn is 80 at%, preferably 75 at%, and more preferably 70 at%. When the content A _{Sn of} the sputtering target is less than the lower limit, there is a concern that Sn oxide is insufficient in the dielectric layer and it is difficult to provide the dielectric layer with an oxygen barrier function to prevent decomposition of the recording layer. On the other hand, when the content A of _Sn exceeds the above-mentioned upper limit, the content of oxides of other elements may be insufficient.

The lower limit of the content of _Zr of this sputtering target with respect to all elements except oxygen, A _Zr , exceeds 0 at%, preferably 5 at%, and more preferably 10 at%. On the other hand, the upper limit of the Zr content A _Zr is 40 at%, preferably 35 at%, and more preferably 30 at%. When the Zr content A _{Z r of} the sputtering target is less than the lower limit, there is a concern that Zr oxide is insufficient in the dielectric layer, the oxygen blocking function is reduced, and it is difficult to suppress deterioration of the recording signal of the recording layer. On the other hand, when the content A of _Zr exceeds the upper limit, there is a concern that the content of oxides of other elements may be insufficient.

The Zn content A _Zn satisfies the following formula (1). The lower limit of the value of the following formula (1) is 0, more preferably 0.1, and even more preferably 0.2. On the other hand, the upper limit of the value of the following formula (1) is preferably 0.5, and more preferably 0.4. When the value of the following formula (1) exceeds the upper limit, there is a concern that the Zn oxide in the dielectric layer is increased unnecessarily, and the oxygen barrier function of the dielectric layer is reduced.
A _Zn / (A _Zn + A _Sn ) ≦ 0.6 ･ ･ ･ ･ ･ (1)

This sputtering target does not contain In. Specifically, the content of In is less than 100 ppm, which is the detection limit. Since this sputtering target does not contain the In element designated as a specific chemical substance, it is not necessary to take measures to prevent health disorders.

Of the multiple specific resistance values measured in this sputtering target, the upper limit of the ratio of the maximum value to the minimum value is 3, more preferably 2.4, and even more preferably 1.7. When the ratio of the maximum value to the minimum value of the specific resistance exceeds the upper limit, there is a concern that an abnormal discharge cannot be sufficiently suppressed when a dielectric layer is formed by a sputtering target using the sputtering target.

The upper limit of the specific resistance value of the sputtering target is 5 × 10 ^-1 (Ω · cm), preferably 3 × 10 ^-1 (Ω · cm), and further preferably 1 × 10 ^-1 (Ω · cm). . When the specific resistance value exceeds the upper limit, there is a concern that an abnormal discharge cannot be sufficiently suppressed when a dielectric layer is formed by a sputtering target using the sputtering target.

This sputtering target has a SnO ₂ phase and a Zn ₂ SnO ₄ phase. The lower limit of the ratio of the Zr element concentration in the Zn ₂ SnO ₄ phase to the Zr element concentration in the SnO ₂ phase is preferably 0.1, more preferably 0.15, and even more preferably 0.2. On the other hand, the upper limit of the ratio of the Zr element concentration is preferably 5, more preferably 4, and even more preferably 3. When the ratio of the Zr element concentration is not in the range of the lower limit and the upper limit, a large amount of ZrO ₂ remains as an insulator, so there is a concern that an abnormal discharge starting from ZrO ₂ may occur.

In addition, the sputtering target has crystal grains of ZrO ₂ . The upper limit of the average particle diameter of the ZrO ₂ crystal particles is preferably 5 μm, more preferably 4 μm, and even more preferably 3 μm. When the average grain size of the crystal grains of ZrO ₂ exceeds the above-mentioned upper limit, there is a concern that an abnormal discharge may occur from ZrO ₂ as an insulator.

[Manufacturing method of sputtering target]
The sputtering target can be obtained by forming a sputtering target that is an oxide sintered body obtained by mixing and sintering oxides of Zn, Sn, and Zr. The manufacturing method of the sputtering target demonstrated below shows an example, and it is not limited to this manufacturing method.

Specifically, the method for producing a sputtering target includes a step (S01) of mixing Zn, Sn, and Zr, a step of drying the obtained mixture (S02), and sintering the dried mixture to form an oxide. A step (S03) of the sintered body, a step (S04) of forming the oxide sintered body, and a step (S05) of joining the formed article to a backing plate.

＜ Mixing step ＞
In the step (S01) of mixing Zn, Sn, and Zr, powdery Zn, Sn, and Zr are prepared and mixed at predetermined ratios, respectively. The purity of each raw material powder used is preferably 99.99% or more. If the purity of each raw material powder is less than the said lower limit, there exists a possibility that the characteristic of the dielectric layer formed using this sputtering target may be impaired. With respect to all metal elements other than oxygen contained in the oxide sintered body, the blending ratio of each raw material powder is such that Zn is more than 0 at% and 50 at% or less, Sn is 20 at% and 80 at% or less, Zr is adjusted so that it exceeds 0 at% and 40 at% or less, and the ratio of the content of Zn to the sum of the contents of Zn and Sn is 0.6 or less.

The means for mixing is not particularly limited. For example, a ball mill can be used to mix each raw material powder and water into the ball mill. For the purpose of uniform mixing, a dispersant may be used together with water, and in order to facilitate molding in a preforming step described later, a binder may also be used. The material of the balls or beads of the ball mill is not particularly limited, and examples thereof include nylon, alumina, and zirconia.

＜ Drying step ＞
In the drying step (S02), for example, a spray dryer or the like is used to dry the mixture obtained in the mixing step (S01). Preferably, the mixture is pre-formed after drying. When a dispersant or a binder is used, the mixture is preferably degreased.

(Preforming step)
In order to improve the workability when installed in a sintering furnace, the dried mixture is preferably preformed. The method of the preforming is not particularly limited, and examples thereof include filling a dried mixture into a mold having a predetermined size, and performing preforming by die pressing. The pressing force by the die pressing can be set to, for example, 0.5 tonf / cm ² or more and 1.0 tonf / cm ² or less.

(Degreasing step)
In the case where a dispersant or a binder is added in the mixing step (S01), in order to remove the dispersant or the binder, the dried mixture or the preform is preferably heated and degreased. The heating conditions are not particularly limited. For example, as long as it is in the air, the dispersant or the binder can be removed by setting the heating temperature to 500 ° C. and the holding time to 5 hours.

<Sintering step>
In the sintering step (S03), the dried mixture in the drying step (S02) is sintered to prepare an oxide sintered body. The oxide sintered body is the sputtering target. In addition, a SnO ₂ phase and a Zn ₂ SnO ₄ phase are formed in the sputtering target by sintering, thereby forming ZrO ₂ crystal grains. The lower limit of the sintering heating temperature is preferably 900 ° C, more preferably 920 ° C, and even more preferably 940 ° C. On the other hand, the upper limit of the heating temperature is preferably 1100 ° C, and more preferably 1050 ° C. When the heating temperature is less than the lower limit, there is a concern that the oxide sintered body cannot be sufficiently densified and the material strength is reduced. On the other hand, when the heating temperature exceeds the upper limit, there is a concern that crystal grains become coarse and the strength of the material decreases.

The upper limit of the average heating rate to the heating temperature is preferably 600 ° C / hr, more preferably 500 ° C / hr, and even more preferably 400 ° C / hr. When the average temperature rise rate exceeds the upper limit, there is a concern that abnormal growth of crystal grains is likely to occur and the relative density of the oxide sintered body may not be sufficiently increased.

The lower limit of the holding time of the heating temperature is preferably 0.5 hours, more preferably 2 hours, and even more preferably 3.5 hours. On the other hand, the upper limit of the holding time is preferably 24 hours, more preferably 12 hours, and even more preferably 8 hours. By setting the holding time to the range, a desired compound phase can be obtained.

After the heating, the heating is preferably performed under conditions of a heating temperature of 400 ° C. to 700 ° C. and a holding time of 1 hour to 10 hours. This can further increase the relative density of the oxide sintered body.

The sintering is preferably performed under a reducing environment. By performing the sintering under a reducing environment such as a carbon monoxide (CO) environment, a vacuum environment, and the like, the specific resistance can be reduced. Regarding the detailed mechanism, there are undetermined parts. However, it is considered that the carrier is increased and the conductivity is improved by processing in a reducing environment where an oxygen deficiency occurs.

Alternatively, carbon (C) may be added to the material powder and water in the mixing step (S01), and the mixture may be dried (S02) to sinter the dried mixture. Since C exists in the dried mixture, a reduction reaction occurs by heating, and the same effect as that of sintering in a reducing environment can be obtained.

＜ Forming step ＞
In the forming step (S04), the oxide sintered body (sputter target) is formed into a shape corresponding to various uses. The forming method is not particularly limited, and for example, Cold Isostatic Pressing (CIP) can be used. The lower limit of the pressing force by CIP is preferably 800 kgf / cm ² , more preferably 900 kgf / cm ² , and even more preferably 1000 kgf / cm ² . When the pressing force by the CIP is less than the lower limit, there is a concern that the relative density of the oxide sintered body cannot be sufficiently increased.

＜ Joining procedure ＞
In the bonding step (S05), the formed article is bonded to the base plate to obtain a sputtering target. The raw material of the base plate is not particularly limited, and pure copper or a copper alloy having excellent thermal conductivity is preferred. The means for joining is not particularly limited, and for example, joining can be performed by a joining agent. The type of the bonding agent is not particularly limited, and various known bonding agents having conductivity can be used, and examples thereof include Sn-based solder materials. The bonding method is not particularly limited. For example, the molded article and the base plate can be heated to a temperature at which the bonding agent melts, for example, 140 ° C or higher and 240 ° C or lower. After the bonding surface is crimped, it is cooled.

[advantage]
The sputtering target and the sputtering target contain respective oxides of Zn, Sn, and Zr, and the content of these elements with respect to all elements other than oxygen is within a predetermined range, so that a dielectric layer having excellent characteristics can be formed. In addition, since the ratio of the maximum value to the minimum value of the specific resistance value and the specific resistance value are in a predetermined range, abnormal discharge during sputtering can be suppressed, and generation of particles can be reduced. Furthermore, since it does not contain In, it is not necessary to take measures to prevent health disorders. Accordingly, by using the sputtering target and the sputtering target, an optical recording medium can be safely and efficiently produced.

According to this method for manufacturing a sputtering target, a sputtering target having excellent strength can be obtained. Therefore, it is possible to suppress cracks caused by an impact during the work in the joining step (S05) or a stress generated during a thermal history of sputtering. In addition, according to the method for manufacturing the sputtering target, specific resistance, the ratio of the concentration of the Zr element in the Zn ₂ SnO ₄ phase to the concentration of the Zr element in the SnO ₂ phase, and the average grain size of the ZrO ₂ crystal grains can be easily changed. The diameter is set to a desired value. This makes it relatively easy to manufacture a sputtering target that can safely and effectively form a dielectric layer.
[Example]

Hereinafter, the present invention will be described in more detail through examples, but the present invention is not limited to these examples.

Samples 1 to 3 with the preparation conditions of Zn, Sn, and Zr set to Table 1 were used, and the molded articles of Examples 1 to 4 and Comparative Examples 1 to 3 were obtained under the manufacturing conditions of Table 2. . The thickness of the molded product was set to 6 mm. In the mixing step, water and ammonium polycarboxylate are mixed into samples 1 to 3, respectively. In the sintering step, hot pressing is performed under a reducing environment. In addition, "N ₂ " in Table 2 means nitrogen.

[Table 1]

[Table 2]

＜ Identification of phases ＞
The phases of Examples 1 to 4 and Comparative Examples 1 to 3 were identified by X-ray diffraction under the following conditions. Furthermore, the notation method is based on the chemical formula of the card number of the International Centre for Diffraction Data (ICDD).
74-2184: Zn ₂ SnO ₄
77-0447: SnO ₂
74-1200: ZrO ₂
86-2265: Sn
750576: ZnO
Analysis conditions:
Target: Cu
Monochrome: use a monochromator (K _α )
Target output: 40 kV-200 mA
(Continuous firing measurement) θ / 2θ scanning slit: divergence angle: 1/2 °, scattering angle: 1/2 °, light receiving width: 0.15 mm
Monochromator light receiving slit width: 0.6 mm
Scanning speed: 2 ° / min
Sampling interval: 0.02 °
Measurement angle (2θ): 5 ° ~ 90 °
Analysis device: "X-ray diffraction device RINT-1500" manufactured by Rigaku

<Evaluation of Zr content and average particle size>
The evaluation of the amount of Zr (the concentration of the Zr element) in the molded product and the measurement of the average particle diameter of the crystal grains of ZrO ₂ were performed by the following procedures.
(1) The molded article is cut at an arbitrary position in the thickness direction, and the cut surface is mirror-polished at an arbitrary position.
(2) Using a scanning electron microscope (SEM) to take a photograph of the structure of the mirror-polished cut surface at a magnification of 10,000 times, and use energy dispersive X-ray spectroscopy (EDS) to identify the phase. The solid solution amount of Zr detected by SEM and EDS was set as the Zr element concentration. Moreover, the average particle diameter of the crystal grains of ZrO ₂ detected by SEM and EDS was measured.
(3) A ratio of the Zr element concentration of the SnO ₂ phase and the Zn ₂ SnO ₄ phase is calculated.
Analysis device:
SEM: "JSM-7800F" manufactured by Japan Electronics Co., Ltd.
EDS: "JED-2300" manufactured by Japan Electronics Co., Ltd.

<Method for measuring specific resistance>
The specific resistance was measured by the 4-probe method. Specifically, the surface of the molded article is mirror-polished to smooth it. From the center of the molded article, a probe having a distance of 1.5 mm between the contact terminals was measured at 10 mm intervals. The specific resistance value is an average value of the values measured at 10 places, and the ratio of the maximum value to the minimum value of the specific resistance value measured at 10 places is calculated, that is, the "specific resistance deviation" described later.
Measuring device: "Loresta GP measuring device" manufactured by Mitsubishi Chemical Analytech

＜ Relative density ＞
The relative density is obtained from the porosity measured as follows. First, a molded article is cut at an arbitrary position in the thickness direction, and the cut surface is mirror-polished at an arbitrary position. Next, the polished surface was photographed at 1000 times using an SEM, and the area ratio (%) of the pores occupied by the area of 50 μm square was measured as the porosity. The same operation was performed on 20 locations, and the average value was set to the average porosity (%) of the sample. The relative density is calculated from [100-average porosity] (%).

＜ Presence or absence of abnormal discharge ＞
The presence or absence of abnormal discharge was confirmed as follows. The formed articles of Examples 1 to 4 and Comparative Examples 1 to 3 were set as sputtering targets. Using this sputtering target, a dielectric layer was formed on the recording layer by a sputtering method under conditions of a DC sputtering power of 200 W, an Ar / 0.1 vol% O ₂ environment, and a pressure of 0.3 Pa, and an arc per 100 minutes was calculated. The number of times of discharge was generated to confirm abnormal discharge during formation.

The measurement results are shown in Table 3. The "specific resistance deviation" in Table 3 indicates the ratio of the maximum value to the minimum value of the specific resistance. The "Zr amount ratio" means the ratio of the Zr element concentration in the Zn ₂ SnO ₄ phase to the Zr element concentration in the SnO ₂ phase. "-" Means no data were obtained.

[table 3]

In Comparative Example 1, it was difficult to cause reduction of the oxide, so the specific resistance became large, and abnormal discharge occurred. In Comparative Example 2, since the content of Sn exceeds 80 at% and the content of Zr is 0 at%, the specific resistance becomes large and abnormal discharge occurs. In Comparative Example 3, the reduction during sintering in an N ₂ environment became unstable, and the outermost part affected, so the variation in the specific resistance became large, and abnormal discharge occurred.
[Industrial availability]

The sputtering target and the sputtering target of the present invention do not require a health obstacle prevention measure and can suppress abnormal discharge, and therefore can be preferably used for the production of an optical recording medium.

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Claims (5)

A sputtering target includes an oxide of zinc (Zn), an oxide of tin (Sn), and an oxide of zirconium (Zr), and the content of zinc A with respect to all elements other than oxygen (O) is _Zn. exceeds 0 at% and 50 at% or less and Sn content _{of Sn} a 20 at% or more and 80 at% or less, and the content of zirconium _Zr a more than 0 at% and 40 at% or less, and the content a Zn _Zn satisfies the following formula (1); the ratio of the maximum value to the minimum value among a plurality of specific resistance values measured is 3 or less, and the specific resistance value is 5 × 10 ^-1 (Ω · cm) or less; The sputtering target does not contain indium (In), and A _Zn / (A _Zn + A _Sn ) ≦ 0.6 ･ ･ ･ ･ ･ (1). The sputtering target according to item 1 of the patent application scope, which has a SnO ₂ phase and a Zn ₂ SnO ₄ phase, and the Zr element concentration in the Zn ₂ SnO ₄ phase is relative to the Zr element in the SnO ₂ phase. The ratio of the concentrations is 0.1 or more and 5 or less. The patentable scope of the application of paragraph 1 sputtering target, comprising a crystalline ZrO ₂ grains of the ZrO ₂ crystal grains of an average particle diameter of 5 μm or less. The patentable scope of the application of paragraph 2 sputtering target, comprising a crystalline ZrO ₂ grains of the ZrO ₂ crystal grains of an average particle diameter of 5 μm or less. A sputtering target includes the sputtering target according to any one of claims 1 to 4 of the scope of patent application.