KR20200053469A - Sputtering target - Google Patents

Abstract

Zn and Sn and O as the main components, Zn and Sn in an atomic ratio of Zn / (Zn + Sn) is contained within a range of 0.1 or more and 0.6 or less, the tin oxide phase and tin zinc composite oxide phase as a main phase, It has a metal tin phase, and the amount of Sn present as the metal tin phase is within the range of 1.0 mol% or more and 8.0 mol% or less, the average value of the equivalent diameter of the metal tin phase is 1 µm or less, and the relative density is 95% It is characterized by the above.

Description

Sputtering target

The present invention relates to a sputtering target used when forming an oxide film containing Zn, Sn and O as the main components.

This application claims priority based on Japanese Patent Application No. 2017-176800 for which it applied to Japan on September 14, 2017, and uses the content here.

The above-described oxide films containing Zn, Sn, and O as the main components have excellent transmittance in the visible light region and have excellent infrared reflecting properties, and are used for heat shielding films such as window panes and infrared filters.

Here, the oxide film mentioned above is formed into a film by sputtering using a sputtering target which consists of oxide, for example as shown in following patent documents 1-5. Further, as the sputtering targets described above, for example, those having a flat plate shape or a cylindrical shape are provided.

In Patent Document 1, a sputtering target composed of an oxide sintered body mainly composed of a tin zinc composite oxide phase and a metal tin phase is proposed.

In addition, in Patent Documents 2 and 3, sputtering targets made of an oxide sintered body of Zn and Sn are proposed.

In addition, Patent Document 4 proposes a sputtering target composed mainly of a tin-zinc composite oxide phase and a tin oxide phase as an oxide sintered body substantially composed of tin, zinc, and oxygen.

Further, in Patent Document 5, a sputtering target in which at least one metal oxide of zinc oxide and tin oxide and a metal powder are sintered is proposed.

Japanese Patent Application Publication No. 2013-177260 (A) Japanese Patent Application Publication No. 2010-037161 (A) Japanese Patent Application Publication No. 2010-031364 (A) Japanese Patent Application Publication No. 2007-314364 (A) Japanese Patent Application Publication No. 2014-167162 (A)

By the way, in the sputtering target described in Patent Document 1, the tin tin oxide (SnO) is used as a raw material and the metal tin phase is formed by reducing the stannous oxide (SnO), but the relative density is about 91.1 to 93.6%. , A sufficiently high density was not obtained.

Moreover, since the tin-zinc composite oxide phase and the metal tin phase are the main phases, on the target sputtering surface, a specific resistance value is significantly different in the area of the tin-zinc composite oxide phase and the area of the metal tin phase, resulting in abnormal discharge during sputtering. There was a fear that the number of times would increase. In addition, since the coefficient of thermal expansion of the tin-zinc composite oxide phase and the metal tin phase is greatly different, when the temperature is increased during sputtering, there is a fear that the target surface is cracked by thermal expansion and sputtering cannot be stably performed.

In addition, in the sputtering targets described in Patent Documents 2 and 3, since the resistance of the target itself is very high and DC (direct current) sputtering is difficult, it is premised to perform RF (high frequency) sputtering. In this RF (high frequency) sputtering, there was a problem that the film-forming speed was slow and the productivity was lowered.

In addition, in the sputtering target described in Patent Document 4, although DC sputtering is described as possible, it is difficult to stably perform DC (direct current) sputtering because its specific resistance is relatively high, for example, several 10 Ω · cm. Did.

In addition, in the sputtering target described in Patent Document 5, since the metal powder and the oxide are sintered, the conductivity of the target is improved and the DC sputtering is possible because the metal powder is dispersed and exists as a metal phase. However, in Patent Document 5, since the metal powder and the oxide are simply sintered, if the sintering temperature is set to be higher than the melting point of the metal powder, the metal powder is eluted, so the sintering temperature cannot be set high and the density is sufficiently improved. It was difficult to make. In addition, since the metal phase is composed of the metal powder used for sintering, the size of the metal phase depends on the particle diameter of the metal powder, so it is difficult to disperse the fine metal phase uniformly and without segregation.

As described above, in the sputtering target described in Patent Document 5, since there are many voids and the metal phase is non-uniform, there is a concern that the number of occurrences of abnormal discharge during sputtering may increase. In addition, there was a fear that cracking occurred during sputtering and sputtering could not be stably performed.

The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a sputtering target capable of stably DC sputtering while being capable of suppressing occurrence of abnormal discharge and having a sufficiently low specific resistance.

In order to solve the above problems, the sputtering target of one aspect of the present invention (hereinafter referred to as "the sputtering target of the present invention") has Zn and Sn and O as the main components, and Zn and Sn in atomic ratios of Zn / ( Zn + Sn) is contained within a range of 0.1 or more and 0.6 or less, the tin oxide phase and the tin zinc composite oxide phase are main phases, and the metal tin phase is present, and the amount of Sn present as the metal tin phase is 1.0 mol% or more. It is characterized in that it is within a range of 8.0 mol% or less, the average value of the circular equivalent diameter of the metal tin phase is 1 µm or less, and the relative density is 95% or more.

According to the sputtering target of the present invention, a tin oxide phase and a tin zinc composite oxide phase are used as main phases, and a metal tin phase is provided, and the average value of the equivalent diameter of the metal tin phase in the cross section of the sputtering target is Since it is 1 µm or less, the metallic tin phase is uniformly present without segregation, and occurrence of abnormal discharge during sputtering can be suppressed. Moreover, the relative density can be improved by finely depositing the metal Sn so as to fill between the particles between the oxide phases forming the mother phase. And even when the temperature rises during sputtering, the occurrence of cracks on the target surface due to thermal expansion can be suppressed.

In addition, "the tin oxide phase and a tin zinc composite oxide phase are made into a main phase" means that the proportion (mol%) of each of the tin oxide phase and the tin zinc composite oxide phase among the phases constituting the sputtering target is greater than that of the other phases. it means.

In addition, "as Zn, Sn, and O as a main component" means that each atomic ratio (at%) of Zn, Sn, and O in a sputtering target composition is 10 at% or more.

In addition, in the sputtering target of the present invention, since the relative density is 95% or more, there are few voids, and occurrence of abnormal discharge during sputtering can be suppressed. Moreover, generation | occurrence | production of the crack in sputtering can be suppressed.

Further, in the sputtering target of the present invention, Zn and Sn are contained in an atomic ratio such that Zn / (Zn + Sn) is in the range of 0.1 to 0.6, so that an oxide film having excellent transmittance and infrared reflecting properties can be formed.

In addition, in the sputtering target of the present invention, since the amount of Sn present as the metal tin phase is 1.0 mol% or more, the specific resistance value is sufficiently low, and the oxide film can be stably formed by DC sputtering.

On the other hand, since the amount of Sn present as the metal tin phase is 8.0 mol% or less, the metal tin phase does not exist more than necessary, and it is possible to suppress the elution of the metal when heated in the manufacturing process, thereby stably sputtering target. Can be produced. Moreover, even when the temperature rises during sputtering, the occurrence of cracks on the target surface due to thermal expansion can be suppressed.

Here, the sputtering target of the present invention may further contain an oxide of one or more metal elements M selected from Cr, V, Si, Ti, Al, and Zr.

In this case, tin oxide can be reduced by one or two or more metal elements M selected from Cr, V, Si, Ti, Al, and Zr, and a metal tin phase can be formed in the sputtering target. Therefore, the specific resistance value is sufficiently low, and it becomes possible to stably form an oxide film by DC sputtering.

Moreover, in the sputtering target of this invention, it is preferable to contain the said metal element M so that M / (Zn + Sn + M) in atomic ratio may be 0.001 or more and 0.05 or less.

In this case, tin oxide can be reliably reduced by the metal element M to form a metal tin phase. Therefore, the specific resistance value is sufficiently low, and it becomes possible to stably form an oxide film by DC sputtering. And it becomes possible to maintain various characteristics in the formed oxide film.

According to the present invention, it is possible to suppress the occurrence of abnormal discharge and to provide a sputtering target capable of stably DC sputtering with a sufficiently low specific resistance value.

1 is a tissue observation photograph (EPMA image) of a sputtering target according to an embodiment of the present invention.
2 is a flowchart showing an example of a method of manufacturing a sputtering target according to an embodiment of the present invention.

Hereinafter, a sputtering target which is one embodiment of the present invention will be described with reference to the accompanying drawings.

The sputtering target according to the present embodiment contains Zn, Sn, and O as main components, and contains Zn and Sn in an atomic ratio such that Zn / (Zn + Sn) is in a range of 0.1 or more and 0.6 or less.

Moreover, the sputtering target which is this embodiment has a tin oxide phase and a tin zinc composite oxide phase as main phases, and has a metal tin phase. In addition, in the present embodiment, as a result of the X-ray diffraction analysis, it was confirmed that the tin oxide phase is the stannous oxide phase (SnO ₂ phase) and the tin zinc composite oxide phase is the Zn ₂ SnO ₄ phase.

And in the sputtering target which is this embodiment, the average value of the circular equivalent diameter of the observed metallic tin phase is 1 micrometer or less, and the above-mentioned metallic tin phase is uniformly dispersed without segregation.

That is, in the sputtering target which is the present embodiment, the metal tin phase is dispersed in the oxide phase (tin oxide phase and tin zinc composite oxide phase) serving as a mother phase. In addition, as described later, this metal tin phase is formed by reduction of tin oxide.

Here, the amount of Sn present as the metal tin phase described above is within a range of 1.0 mol% or more and 8.0 mol% or less.

Moreover, in the sputtering target which is this embodiment, the relative density is 95% or more.

In addition, in the sputtering target according to the present embodiment, the specific resistance is 1 Ω · cm or less.

Here, in the sputtering target according to the present embodiment, an oxide of one or more metal elements M selected from Cr, V, Si, Ti, Al, and Zr may be further contained.

Moreover, in the sputtering target which is this embodiment, when it has the oxide phase of metal element M, the content of metal element M is set so that M / (Zn + Sn + M) is 0.001 or more and 0.05 or less in atomic ratio. desirable.

That is, in the sputtering target according to the present embodiment, Zn, Sn, O, and a metal element M are added as necessary, and the composition is composed of other inevitable impurities.

Below, the atomic ratio in the sputtering target of the present embodiment, the average value of the observed equivalent diameter of metal tin, the amount of Sn contained as the metal tin phase, relative density, specific resistance, and metal element M are as described above. The reason specified together will be explained.

(Atomic Ratio Zn / (Zn + Sn): 0.1 or more and 0.6 or less)

In the sputtering target of the present embodiment, it is necessary to satisfy the transmittance in the visible light region and the infrared reflecting property by forming an oxide film to be a heat shielding film.

Here, by containing Zn and Sn in an atomic ratio such that Zn / (Zn + Sn) is within a range of 0.1 or more and 0.6 or less, an oxide film satisfying the various properties described above can be formed.

Moreover, in order to reliably form an oxide film excellent in various properties, the lower limit of the atomic ratio Zn / (Zn + Sn) is preferably 0.2 or more, more preferably 0.25 or more. Further, the upper limit of the atomic ratio Zn / (Zn + Sn) is preferably 0.5 or less, more preferably 0.4 or less.

(The average of the equivalent diameter of the metal tin phase is 1 µm or less)

In the structure of the sputtering target, when the average equivalent diameter of the metal tin phase observed exceeds 1 µm, the number of occurrences of abnormal discharges increases and there is a fear that stutter film formation cannot be stably performed. Moreover, when the circular equivalent diameter of the metal tin phase is large, the deposited metal tin phase cannot fill up the particles between the oxide phases, and there is a concern that the relative density may decrease. In addition, since the difference in thermal expansion coefficient between the metal tin phase and the oxide phase serving as the mother phase is large, when the temperature increases during sputtering, there is a fear that the target surface may crack due to the difference in the thermal expansion coefficient between the metal tin phase and the oxide phase. .

From the above, in this embodiment, the average value of the observed metal tin phase equivalent diameter is limited to 1 µm or less.

In addition, in order to further suppress the occurrence of abnormal discharge and sputtering cracks and to sufficiently improve the relative density, it is more preferable to set the average of the observed equivalent diameters of the metallic tin phase to 0.65 µm or less, and 0.60. It is more preferable to make it into micrometers or less.

Here, in the present embodiment, since it is difficult to observe a metal tin phase having a circle equivalent diameter of less than 0.1 μm, the “average of the circle equivalent diameter of the observed metal tin phase” means that the circle equivalent diameter of a metal tin phase having a circle equivalent diameter of 0.1 μm or more It is set as the average value.

(Sn content as metal tin phase: 1.0 mol% or more and 8.0 mol% or less)

In the sputtering target which is the present embodiment, the oxide film described above is formed by DC sputtering.

Here, when the amount of Sn present as a metal tin phase is less than 1.0 mol%, the specific resistance increases, and there is a fear that the DC sputtering cannot be stably performed. Moreover, there is a fear that the density cannot be sufficiently improved.

On the other hand, when the amount of Sn present as the metal tin phase exceeds 8.0 mol%, there is a fear that elution of the metal occurs during sintering and the sputtering target cannot be stably produced. In addition, many metal tin phases having significantly different thermal expansion coefficients from the oxide phase serving as the mother phase existed, and when the temperature increased during sputtering, there was a fear that the target surface would crack due to thermal expansion.

For this reason, in this embodiment, the amount of Sn existing as a metal tin phase is set in the range of 1.0 mol% or more and 8.0 mol% or less.

Here, in order to further perform the DC sputtering more stably by lowering the specific resistance, the lower limit of the amount of Sn present as the metal tin phase is preferably 3.0 mol% or more, and more preferably 4.5 mol% or more. Moreover, in order to suppress the elution of metal during sintering and to stably produce a sputtering target, the upper limit of the amount of Sn present as the metal tin phase is preferably 7.5 mol% or less, and 7.0 mol% or less. It is more preferable.

In addition, about the amount of Sn present as a metal tin phase in the sputtering target according to the present embodiment, a sample taken from the sputtering target is pulverized into a powder, and this powder is used to measure by powder X-ray diffraction, It can calculate by performing an analysis by the Rietveld method.

(Relative density: 95% or more)

The relative density is the measurement density divided by the theoretical density. In the present embodiment, the theoretical density was calculated by the following equation, assuming that the remaining Sn and Zn were SnO ₂ and ZnO, respectively, by calculating the amount of Sn present as the metal tin phase by the Rietveld method. .

Theoretical density = 100 / {(Wa / Da) + (Wb / Db) + (Wc / Dc)}

Wa: SnO ₂ content (mass%)

Da: The theoretical density of SnO ₂ (6.95 g / cm 3)

Wb: Content of ZnO (mass%)

Db: The theoretical density of ZnO (5.61 g / cm 3)

Wc: Metal Sn content (mass%)

Dc: theoretical density of metal Sn (7.30 g / cm 3)

If the relative density of the sputtering target calculated by the above formula is less than 95%, there are many voids, and abnormal discharge may easily occur during sputtering. Moreover, after sputtering, there is a possibility that cracks will occur in the sputtering target. Therefore, in this embodiment, the relative density is specified to be 95% or more. Here, the density of the sputtering target may exceed the theoretical density calculated by the above formula due to the reaction of the raw material powder or the like, and in this case, the relative density exceeds 100%.

In addition, in order to further suppress the occurrence of abnormal discharge and cracking during sputtering, it is preferable to set the relative density of the sputtering target to 96% or more, and more preferably 98% or more. Moreover, although there is no restriction | limiting in particular in the upper limit of a relative density, For the sintered compact which is 105% or more of relative density, since manufacturing is difficult, it is less than 105%, for example.

(Specific resistance value: 1 Ω · cm or less)

In order to stably perform DC sputtering, in the sputtering target of the present embodiment, the specific resistance is preferably 1 Ω · cm or less, and more preferably 0.1 Ω · cm or less. The lower limit of the specific resistance value is not particularly limited, but is, for example, 0.001 Ω · cm or more.

(Metal element M)

Since one or more metal elements M selected from Cr, V, Si, Ti, Al, and Zr are elements capable of reducing tin oxide to form a metal tin phase, these metal elements M may be contained. . In addition, since the metal element M reduces tin oxide as described above during sintering, it exists as an oxide phase (MOX) in the sputtering target.

Here, in the sputtering target according to the present embodiment, when the metal element M is contained, the content of the metal element M is set to 0.001 or more in an atomic ratio of M / (Zn + Sn + M), thereby reducing tin oxide and sufficiently providing a metal tin phase. Can form. On the other hand, by setting M / (Zn + Sn + M) to 0.05 or less in the atomic ratio, the influence on the properties of the film to be formed can be suppressed.

From the above, in the case of containing the metal element M in the present embodiment, it is preferable that the M / (Zn + Sn + M) is within the range of 0.001 to 0.05 in atomic ratio.

The lower limit of M / (Zn + Sn + M) is preferably 0.0015 or more, and more preferably 0.002 or more. On the other hand, the upper limit of M / (Zn + Sn + M) is preferably 0.01 or less, and more preferably 0.008 or less.

(Manufacturing method of sputtering target)

Next, the manufacturing method of the sputtering target which is this embodiment is demonstrated with reference to the flowchart of FIG.

First, a raw material powder containing zinc oxide powder and tin oxide powder is prepared (raw material powder preparation step (S01)). In addition, in this embodiment, the tin oxide powder (SnO ₂ ) is used as tin oxide powder.

Here, as the raw material powder, a metal zinc powder or a powder of metal element M is contained to reduce tin oxide to form a metal tin phase. That is, as the raw material powder, (1) zinc oxide powder + tin oxide powder + metal zinc powder, (2) zinc oxide powder + tin oxide powder + metal element M powder, (3) zinc oxide powder + tin oxide powder + It can be mixed in a pattern of a powder of metal zinc powder + metal element M. Then, the weighed raw material is mixed using a ball mill or the like.

The mixed raw material powder is filled into a mold, heated under pressure and sintered to obtain a sintered body (sintering step (S02)).

Further, the sintering temperature at this time is preferably in the range of 950 ° C or higher and 1200 ° C or less, the holding time at the sintering temperature is in the range of 180 min or more and 300 min or less, and the pressurized pressure is within the range of 20 MPa or more and 40 MPa or less. Do. Moreover, it is preferable to set it as a vacuum atmosphere (20 kPa or less).

In this sintering step (S02), the metal tin phase is uniformly formed without segregation by reducing the metal oxide (or metal element M) to tin oxide. That is, in this embodiment, a metal tin phase is formed by reaction sintering.

By performing the reaction sintering in this way, the average value of the equivalent diameter of the metal tin phase observed becomes 1 µm or less. Moreover, when a metal tin phase is filled between oxide phases, relative density will improve.

In addition, although the sintering temperature is set to a temperature exceeding the melting point (419.5 ° C) of the metal zinc, the metal zinc becomes zinc oxide during the sintering process, so elution of the metal zinc is suppressed. Moreover, although the sintering temperature is set to a temperature exceeding the melting point (231.9 ° C) of the metal tin, elution of the metal tin is suppressed because the metal tin phase is finely formed during the sintering process.

Next, the obtained sintered body is machined (mechanical processing step (S03)). Thereby, the sputtering target which is this embodiment is manufactured.

In the sputtering target according to the present embodiment having the above structure, the tin oxide phase and the tin zinc composite oxide phase are used as the main phase, and the metal tin phase has an average value of the equivalent diameter of the observed metal tin phase of 1 µm. Since it is as follows, the metal tin phase is uniformly present without segregation, and occurrence of abnormal discharge during sputtering can be suppressed. In addition, the metal tin phase is sufficiently filled between the oxide phases serving as the mother phase, and the relative density can be improved. And even when the temperature rises during sputtering, the occurrence of cracks on the target surface due to thermal expansion can be suppressed.

Moreover, in the sputtering target which is this embodiment, since the relative density is 95% or more, there are few voids, and occurrence of abnormal discharge during sputtering can be suppressed. Moreover, generation | occurrence | production of the crack in sputtering can be suppressed.

In addition, in the sputtering target according to the present embodiment, Zn and Sn are contained in an atomic ratio such that Zn / (Zn + Sn) is in a range of 0.1 to 0.6, so that an oxide film having excellent transmittance and infrared reflecting properties can be formed.

Moreover, in the sputtering target which is this embodiment, since the amount of Sn present as a metal tin phase is 1.0 mol% or more, the specific resistance value is sufficiently low, and it becomes possible to form an oxide film stably by DC sputtering.

On the other hand, since the amount of Sn present as the metal tin phase is 8.0 mol% or less, the metal tin phase does not exist more than necessary, and it is possible to suppress the elution of the metal when heated in the manufacturing process, thereby stably producing a sputtering target. can do. Moreover, even when the temperature rises during sputtering, the occurrence of cracks on the target surface due to thermal expansion can be suppressed.

And in the sputtering target which is this embodiment, when it contains the oxide of 1 or 2 or more types of metal elements M chosen from Cr, V, Si, Ti, Al, and Zr, by the metal element M The metal tin phase described above can be formed by reducing tin oxide. Therefore, the specific resistance value is sufficiently low, and it becomes possible to form an oxide film stably by DC sputtering.

In addition, in the sputtering target according to the present embodiment, by containing the metal element M in an atomic ratio such that M / (Zn + Sn + M) is within the range of 0.001 or more and 0.05 or less, the metal element M reliably reduces tin oxide to reduce metal oxide. It is possible to form a gargoyle, the specific resistance is sufficiently low, it is possible to stably form an oxide film by DC sputtering, and it is possible to maintain various characteristics of the formed oxide film.

In addition, in the present embodiment, as the raw material powder, either or both of zinc oxide powder and tin oxide powder (SnO ₂ min) and metal zinc powder or powder of metal element M are contained, and the sintering step (S02) is performed. Since the metal tin phase is reacted and sintered to reduce tin oxide by metal zinc or metal element M to form a metal tin phase, the metal tin phase can be formed uniformly and without segregation, and the metal can be formed even if the sintering temperature is set high. Elution of can be suppressed. Specifically, the sintering temperature in the sintering step (S02) can be set to a relatively high temperature condition within a range of 950 ° C to 1200 ° C. Thereby, it becomes possible to obtain a sputtering target having a high relative density.

The embodiments of the present invention have been described above, but the present invention is not limited to this, and can be appropriately changed without departing from the technical spirit of the invention.

For example, in the present embodiment, in the case of further containing one or more metal elements M selected from Cr, V, Si, Ti, Al, and Zr, the content of the metal elements M is in an atomic ratio. Although M / (Zn + Sn + M) was described to be within the range of 0.001 to 0.05, the present invention is not limited to this, and when the metal tin phase is sufficiently formed by metal zinc, the level of M / (Zn + Sn + M) is less than 0.001 by atomic ratio. It may contain. Moreover, M / (Zn + Sn + M) in atomic ratio may exceed 0.05 depending on the characteristics required for the film formed into a film.

Example

Hereinafter, the results of the verification experiment conducted to confirm the effectiveness of the present invention will be described.

(Sputtering target)

As a raw material powder, zinc oxide powder (ZnO powder: purity 99.9 mass% or more, average particle diameter 10.0 µm), stannic oxide powder (SnO ₂ powder: purity 99.99 mass% or more, average particle diameter 25 µm), metal zinc powder (metal Zn Min: purity of 99 mass% or more, and an average particle diameter of 4.0 µm) was prepared. As the metal element M, metal aluminum powder (metal Al powder: purity 99.9 mass% or more, average particle diameter 46.0 µm), and metal zirconium powder (metal Zr powder: purity 98 mass% or more, average particle diameter 10 µm) were prepared. . Then, a metal tin powder (metal Sn powder: purity 99 mass% or more, average particle diameter of 15.0 μm) and a first tin oxide powder (SnO powder: purity 99 mass% or more, average particle diameter of 25 μm) used in the comparative example were prepared. Did.

These raw materials were weighed to the molar ratio shown in Table 1, and a weighed raw material and a zirconia ball (diameter: 5 mm) weighing three times the weight of the raw materials were charged into a pot made of polyethylene in an Ar gas atmosphere. Dry mixing was performed by a ball mill device for 8 hours. After mixing, the mixture was sieved to separate zirconia balls and mixed powder.

The obtained mixed powder was charged into a mold made of carbon, and subjected to pressure sintering in a vacuum atmosphere under conditions of the sintering temperature shown in Table 1, the holding time at the sintering temperature of 4 hours, and the pressure of 35 MPa. A sintered body was obtained.

The obtained sintered body was machined to prepare a sputtering target (126 mm × 178 mm × 6 mm) for evaluation. Then, the following items were evaluated.

(Elution of metal)

The presence or absence of elution of metal (Sn or Zn) during sintering was confirmed by visually observing the sputtering target after sintering. Table 1 shows the evaluation results. In addition, when elution of metal was recognized, the sputtering test described later was not performed.

(Composition of sputtering target)

The measurement sample was taken from the obtained sputtering target, and the collected measurement sample was pulverized to obtain a measurement powder. Using this powder for measurement, measurement was performed by a powder X-ray diffraction apparatus (D8 ADVANCE, manufactured by Bruker AX Co., Ltd.), and the Rietveld method (analysis software: TOPAS manufactured by Bruker AX Co., Ltd. version) The composition of the sputtering target was calculated by performing analysis by 5)). The measurement results are shown in Tables 2 and 3. In addition, the measurement conditions were as follows.

Sailor: Cu

Tube voltage: 40 ㎸

Tube current: 40 ㎃

Injection range: 15 to 128 deg

Step width: 0.01 deg

(Mean value of circle equivalent diameter of metal tin phase)

Observation samples were taken from the sputtering target, and after cross-section polishing, EPMA observation (magnification of 1000 times) was performed to specify a metal tin phase from elemental mapping. Then, the observed equivalent equivalent diameter of the metallic tin phase was obtained using image analysis software: Winroof, and the average value of the equivalent equivalent diameter was calculated.

Table 3 shows the measurement results.

Here, an example of the EPMA image is shown in FIG. 1. In the EPMA image of FIG. 1, the white part is a metal tin phase, the gray part is a tin oxide phase (SnO ₂ ), and the black part is a tin zinc composite oxide phase (Zn ₂ SnO ₄ ).

In the EPMA image shown in FIG. 1, it can be seen that the tin oxide phase and the tin zinc composite oxide phase exist as the main phase in the sputtering target of the present invention, since the gray and black portions occupy a major portion. In addition, it is understood that the sputtering target of the present invention has a metallic tin phase, and the average value of the circular equivalent diameter of the metallic tin phase is about 1 µm or less, in that small white parts smaller than the gray and black parts are scattered and present. .

(Relative density)

"Theory density" was calculated by the method described in the column of the embodiment. In addition, the value obtained by dividing the weight of the obtained sputtering target by the volume obtained from the dimension was taken as the "measurement density".

Using this theoretical density and the measured density of the obtained sputtering target, the theoretical density ratio was calculated by the following equation. Table 3 shows the measurement results.

 Relative density (%) = (measurement density) / (theoretical density) × 100

(Specific resistance value)

The specific resistance value of the sputtering target was measured by a resistance measuring device. The resistance was measured by a four-probe method using a low resistivity meter (Loresta-GP) manufactured by Mitsubishi Chemical Corporation. The temperature at the time of measurement was measured at 23 ± 5 ° C., and the humidity at 50 ± 20%. Table 3 shows the measurement results.

(Number of abnormal discharges)

After the prepared sputtering target is bonded to the backing plate, the sputtering target is used to form a film by sputtering under the following conditions, and the arc count function provided in the DC power supply (HPK06Z-SW6 manufactured by Kyosan) By, the number of abnormal discharges was counted. Table 3 shows the measurement results.

Power: DC

Power: 4.08 W / ㎠

Voltage (全 壓): 0.67 ㎩

Gas atmosphere: Ar 90% + O ₂ 10%

Reach vacuum degree: 7.0 × 10 ^-4 ㎩

Inter-substrate distance: 60 ㎜

Time: 20 minutes

In Comparative Example 1 in which the amount of Sn contained as the metal tin phase was 0.83 mol%, the specific resistance was high and DC sputtering could not be performed. Moreover, the relative density was less than 95%.

In Comparative Example 2 in which the amount of Sn contained as the metal tin phase was 11.75 mol%, elution of the metal was observed during sintering. For this reason, the sputtering test was not performed. Moreover, the relative density was less than 95%.

In Comparative Example 3, which does not contain a tin oxide phase and contains a lot of metal zinc phases, elution of the metal was observed during sintering. For this reason, the sputtering test was not performed. Moreover, the relative density was less than 95%.

In the comparative example 4 in which metal tin powder was used as a raw material and the amount of Sn contained as the metal tin phase was 10.58 mol%, the average value of the equivalent diameter of the metal tin phase was 1.32 μm and exceeded 1 μm. Moreover, the elution of the metal was recognized during sintering. For this reason, the sputtering test was not performed. And the relative density was less than 95%.

In the comparative example 5 in which metal tin powder was used as a raw material and the amount of Sn contained as the metal tin phase was 0.54 mol%, the average value of the equivalent diameter of the metal tin phase was 1.29 μm and exceeded 1 μm. Moreover, the specific resistance was high, and DC sputtering could not be performed. And the relative density was less than 95%.

In Comparative Example 6 in which the sintering temperature was 400 ° C, a metal tin phase was not formed, and a metal zinc phase was formed. It is presumed that tin oxide could not be reduced by metal zinc. Moreover, in this comparative example 6, the elution of metal was recognized. For this reason, the sputtering test was not performed. And the relative density was less than 95%.

In Comparative Example 7 using a powder of stannous oxide (SnO) as the tin oxide powder, a tin oxide phase (SnO ₂ phase) was not formed, and many metal tin phases were formed. Moreover, the average value of the circular equivalent diameter of the metallic tin phase was 3.55 µm, exceeding 1 µm. And the elution of the metal (Sn) was recognized during sintering. For this reason, the sputtering test was not performed. Moreover, the relative density was less than 95%.

On the other hand, in the invention examples 1-10, the metal tin powder was not used as a raw material, but the metal tin phase was formed in the structure after sintering. It is presumed that a metal tin phase is formed by reducing a part of tin oxide by the metal zinc powder used as a raw material and the metal powder of the element M. For this reason, even if the sintering temperature was set high, no elution of the metal was observed during sintering.

In addition, in Examples 1-10 of the present invention, since the sintering temperature was sufficiently high, the relative density also increased to 95% or more.

In addition, in Examples 1-10 of the present invention, the average value of the equivalent diameter of the metal tin in the target is 1 µm or less, and the metal tin phase is uniformly dispersed without segregation, and the specific resistance value is sufficiently lowered. Thereby, the number of occurrences of abnormal discharge during sputtering is also suppressed, and DC sputtering can be stably performed.

Further, in Examples 8 and 9 of the present invention, Al was added as the metal element M, but even if the sintering temperature was set high, no elution of the metal was observed during sintering. And the average value of the equivalent equivalent diameter of the metal tin in the target was 1 µm or less, and the metal tin phase was uniformly dispersed without segregation, and the specific resistance was sufficiently lowered. And the relative density also increased to 95% or more.

Further, in Example 10 of the present invention, Zr was added as the metal element M, but the average value of the equivalent diameter of the metal tin in the target is 1 µm or less, and the metal tin phase is uniformly dispersed without segregation and has a specific resistance value. Is low enough. And the relative density also increased to 95% or more.

As described above, according to the present invention example, it was confirmed that it is possible to suppress the occurrence of abnormal discharge and to provide a sputtering target capable of stably DC sputtering with a low specific resistance value.

Industrial availability

The formation of an oxide film containing Zn, Sn, and O as a main component used for a heat shield film such as a window glass or an infrared filter can be performed more efficiently.

Claims (3)

Zn and Sn and O as main components, and Zn and Sn are contained in an atomic ratio such that Zn / (Zn + Sn) is in a range of 0.1 or more and 0.6 or less,
The tin oxide phase and the tin zinc composite oxide phase are used as the main phase, and the metal tin phase is provided.
The amount of Sn present as the metal tin phase is within a range of 1.0 mol% or more and 8.0 mol% or less,
The average value of the equivalent diameter of the metal tin phase is 1 µm or less,
A sputtering target characterized in that the relative density is 95% or more. According to claim 1,
In addition, a sputtering target characterized by containing an oxide of one or more metal elements M selected from Cr, V, Si, Ti, Al, and Zr. According to claim 2,
A sputtering target comprising the metal element M in an atomic ratio such that M / (Zn + Sn + M) is within a range of 0.001 to 0.05.

Images