KR20190096974A - Oxide Sputtering Target and Manufacturing Method of Oxide Sputtering Target - Google Patents

Abstract

An oxide sputtering target consisting of an oxide containing zirconium, silicon, and indium as a metal component, wherein the ratio of the difference between the maximum and minimum values of the oxygen concentration relative to the sum of the maximum and minimum values of the oxygen concentration in the target surface is 15% or less. Oxide sputtering target to be.

Description

Oxide Sputtering Target and Manufacturing Method of Oxide Sputtering Target

The present invention relates to an oxide sputtering target comprising zirconium oxide, silicon dioxide and indium oxide, and a method for producing an oxide sputtering target.

As the information recording medium, phase change type optical discs such as DVD and BD [Blu-ray (registered trademark) Disc] are known. These phase change type optical disks generally have a laminated body in which a plurality of layers such as a dielectric layer, a recording layer, a dielectric layer, and a reflective layer are laminated on a substrate. As a film-forming method of each layer, sputtering method is widely used. The phase change type optical disc records information by irradiating a recording laser beam to an optical recording medium to cause a phase change of the recording layer.

As a dielectric layer or a protective layer of a phase change type optical disk, an oxide film containing zirconium oxide, silicon dioxide and indium oxide is used (Patent Documents 1 and 2).

Patent document 2 contains zirconium oxide: 10-70%, silicon dioxide: 50% or less (not containing 0%) in mol% as a sputtering target for forming an optical recording medium protective film, and remainder: indium oxide and inevitable. An oxide sputtering target having a composition made of impurities is disclosed. In Patent Document 2, ZrO ₂ powder, amorphous SiO ₂ powder, and In ₂ O ₃ powder are weighed in a predetermined amount and uniformly mixed in a Henschel mixer as a method for producing the oxide sputtering target, and then the mixed powder is press-molded. The method of baking and sintering the obtained molded object in oxygen atmosphere is described.

Japanese Patent No. 4567750 (B) Japanese Patent No. 5088464 (B)

In the phase change type optical disk, with the increase of the recording density, miniaturization of the recording pit and track pitch has progressed, and the management of the mixing of foreign matters is becoming more severe. Therefore, in the oxide sputtering target used for manufacture of a phase change type optical disk, it is calculated | required that a particle does not scatter well.

However, in the manufacturing method of the oxide sputtering target described in patent document 2, the oxygen in baking atmosphere may be insufficient at the time of baking of a molded object. When the molded product is fired in a state in which oxygen in the firing atmosphere is insufficient, the oxygen concentration in the resulting oxide sputtering target becomes nonuniform. When the oxygen concentration in the target surface of the oxide sputtering target becomes large, the specific resistance in the target surface becomes uneven, and abnormal discharge occurs during sputtering due to concentration of potential at a specific point. It turns out that a problem arises that particles are scattered.

This invention is made | formed in view of the above-mentioned situation, and an object of this invention is to provide the oxide sputtering target which can suppress generation | occurrence | production of abnormal discharge during sputtering, and the particle sputtering target, and the manufacturing method of this oxide sputtering target.

In order to solve the said subject, the oxide sputtering target of this invention is an oxide sputtering target which consists of an oxide containing zirconium, silicon, and indium as a metal component, Comprising: The said oxygen with respect to the sum total of the maximum value and minimum value of the oxygen concentration in a target surface. The ratio of the difference between the maximum value and the minimum value of the concentration is characterized by being 15% or less.

According to the oxide sputtering target of this invention with such a structure, since the maximum value and minimum value of oxygen concentration in a target surface satisfy | fill the relationship mentioned above, the dispersion | variation in oxygen concentration in a target surface is suppressed. For this reason, since the uniformity of the oxygen concentration in a target surface becomes high and the specific resistance in a target surface becomes uniform, abnormal discharge during sputtering is suppressed and particle generation is suppressed with this.

Here, in the oxide sputtering target of this invention, it is preferable that the ratio of the difference of the maximum value and minimum value of the specific resistance with respect to the sum total of the maximum value and minimum value of the specific resistance in a target surface is 15% or less.

In this case, since the variation of the specific resistance in the target surface is suppressed in the above range, abnormal discharge during sputtering is further suppressed, and generation of particles is surely suppressed with this.

The manufacturing method of the oxide sputtering target of this invention is a method of manufacturing the above-mentioned oxide sputtering target, The zirconium oxide powder, silicon dioxide powder, and indium oxide powder are mixed, and the specific surface area is 11.5 m <2> / g or more 13.5 m <2> / g A process of obtaining a mixed powder which is below, a process of molding the mixed powder to obtain a molded body, a process of firing the molded body at a temperature of 1300 ° C. or more and 1600 ° C. or less while circulating oxygen into a sintering apparatus, to produce a sintered body, The said sintered compact is equipped with the process of cooling to the temperature at least 600 degrees C or less at the cooling rate of 200 degrees C / hour or less, flowing oxygen in the said baking apparatus.

According to the manufacturing method of the oxide sputtering target of this structure, since the mixed powder which mixed the zirconium oxide powder used as a raw material, the silicon dioxide powder, and the indium oxide powder has a specific surface area of 11.5 m <2> / g or more and 13.5 m <2> / g or less, it is reactive This is high. Moreover, baking of a molded object is performed while circulating oxygen in a baking apparatus, and since oxygen in a baking atmosphere does not run short, sintering of a molded object becomes uniform and a compact and high density sintered compact can be obtained. And since the sintered compact is cooled by the cooling rate of 200 degrees C / hour or less, a sudden temperature change does not occur easily and the oxygen concentration of a sintered compact is stabilized. Therefore, the oxide sputtering target with small dispersion | variation in the oxygen concentration in a target surface can be manufactured stably.

According to this invention, it becomes possible to provide the oxide sputtering target which can suppress generation | occurrence | production of abnormal discharge during sputtering, and the particle | grains scattering, and the manufacturing method of this oxide sputtering target.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows the measurement position of oxygen concentration and specific resistance in the oxide sputtering target which concerns on one Embodiment of this invention.
2 is a flowchart showing a method for producing an oxide sputtering target according to one embodiment of the present invention.
It is explanatory drawing explaining the position which measured the In density | concentration of the oxide film formed into a film in the Example.

EMBODIMENT OF THE INVENTION Below, the oxide sputtering target which is embodiment of this invention is demonstrated with reference to attached drawing.

The oxide sputtering target according to the present embodiment can be used, for example, when forming an oxide film used as a dielectric layer and a protective layer of a phase change type optical disk such as a DVD or a BD by sputtering. The oxide sputtering target of the present embodiment can also be used when forming an oxide film used as a base layer and a protective layer of a magnetic recording medium such as an HDD (hard disk drive) by sputtering.

The oxide sputtering target of this embodiment consists of an oxide containing zirconium, silicon, and indium as a metal component. There is no restriction | limiting in particular in content of zirconium, silicon, and indium, It can be made the same as the oxide used as a sputtering target for conventional optical recording medium protective film formation. In this embodiment, the total content of the metal component is 100 mass%, the content of zirconium is set in a range of 10 mass% to 75 mass%, and the content of silicon is 35 mass% or less (but 0 mass% Not included), and the content of indium is set to remainder. A part of zirconium, silicon, and indium may form a composite oxide, respectively. In ₂ Si ₂ O ₇ is mentioned as an example of a composite oxide.

As for the oxide sputtering target of this embodiment, the ratio of the difference of the maximum value and minimum value of oxygen concentration with respect to the sum total of the maximum value and minimum value of oxygen concentration in a target surface, ie, the deviation of oxygen concentration represented by following formula (1) is 15% or less. It is.

Equation (1):

Deviation (%) of oxygen concentration = [(maximum value of oxygen concentration)-(minimum value of oxygen concentration)] / [(maximum value of oxygen concentration) + (minimum value of oxygen concentration)] × 100

In addition, as for the oxide sputtering target of this embodiment, the ratio of the difference of the maximum value and minimum value of specific resistance with respect to the sum of the maximum value and minimum value of specific resistance in a target surface, ie, the variation of the specific resistance shown by following formula (2), becomes 15% or less. have.

Equation (2):

Specific resistance deviation = [(maximum value of specific resistance)-(minimum value of specific resistance)] / [(maximum value of specific resistance) + (minimum value of specific resistance)] × 100

Below, the reason which prescribed | regulated the deviation of the oxygen concentration and specific resistance of the oxide sputtering target of this embodiment as mentioned above is demonstrated.

(Deviation of oxygen concentration)

When the variation in the oxygen concentration of the oxide sputtering target becomes large, abnormal discharge and particles easily occur during sputtering. For this reason, in the oxide sputtering target of this embodiment, the dispersion | variation in the oxygen concentration in the target surface represented by said Formula (1) is set to 15% or less. When the variation in the oxygen concentration exceeds 15%, abnormal discharge and particles are generated, foreign matter adheres to the surface of the formed oxide film, and there is a fear that the in-plane variation of the film composition becomes large. In addition, although the oxygen concentration of an oxide sputtering target changes with content of zirconium, silicon, and indium, it is preferable to exist in the range of 15 mass% or more and 35 mass% or less. Oxygen concentration can be measured by EPMA or gas analysis.

Here, the deviation of oxygen concentration in a target surface measures oxygen concentration in a several point in a target surface, extracts the maximum value and minimum value of the measured oxygen concentration, and calculates it by the said Formula (1). It is preferable to make the measuring point of oxygen concentration into five or more places. Here, in this embodiment, when an oxide sputtering target is a disk form, as shown in FIG. 1, it is two linear forms orthogonal to each other at the center point 1 of a target surface (circle), and the center point of a target surface, In addition, the oxygen concentration is measured at a total of five points of four points (2) to (5) at a position of 20 mm from the outer edge, and the maximum and minimum values of the measured oxygen concentrations are extracted to determine the deviation of the oxygen concentrations.

In the case where the oxide sputtering target has a cylindrical shape, the oxygen concentration is measured at a total of five points located at equal intervals in the circumferential direction at a position of 20 mm from the outer edge, and the maximum and minimum values of the measured oxygen concentrations are extracted to obtain an oxygen concentration. The deviation of can be found.

(Deviation of specific resistance)

When the variation in the specific resistance of the oxide sputtering target becomes large, abnormal discharge and particles are likely to occur during sputtering. For this reason, in the oxide sputtering target of this embodiment, the variation of the specific resistance in the target surface represented by said Formula (2) is set to 15% or less. When the variation in the resistivity exceeds 15%, abnormal discharges and particles are generated, foreign matter adheres to the surface of the formed oxide film, and there is a fear that the in-plane variation of the film composition becomes large. Moreover, it is preferable that the specific resistance of an oxide sputtering target is 0.1 ohm * cm or less.

Here, the variation of the specific resistance in the target surface is measured by measuring the specific resistance at a plurality of points in the target surface, extracting the maximum value and the minimum value of the measured specific resistance, and are calculated by the above formula (2). It is preferable to make the measurement point of a specific resistance into five or more places. Here, in this embodiment, when an oxide sputtering target is a disk form, as shown in FIG. 1, it is two linear forms orthogonal to each other at the center point 1 of a target surface (circle), and the center point of a target surface, In addition, the specific resistance is measured at a total of five points of four points (2) to (5) at a position of 20 mm from the outer edge, and the maximum and minimum values of the measured specific resistances are extracted to determine the deviation of the specific resistance.

When the oxide sputtering target has a cylindrical shape, the resistivity is measured at a total of 5 points located at equal intervals in the circumferential direction at a position of 20 mm from the outer edge, and the maximum and minimum values of the measured resistivity are extracted and the deviation of the resistivity is determined. You can get it.

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

As shown in FIG. 2, the manufacturing method of the oxide sputtering target which concerns on this embodiment is the crushing mixing process S01 which grind | mixes and mixes raw material powder, and the shaping | molding process S02 which shape | mixes the pulverized mixed powder to a predetermined shape, and was shape | molded Sintering process S03 which sinters a molded object, the cooling process S04 which cools the obtained sintered compact, and the processing process S05 which processes the cooled sintered compact are provided.

As a raw material powder, ZrO ₂ powder, SiO ₂ powder, and In ₂ O ₃ powder are prepared. ZrO ₂ powder, it is preferred that the purity is more than 99.9 mass% or more, an average particle size more than 0.2 ㎛ 20 ㎛. SiO ₂ powder, it is preferred that the purity is more than 99.8 mass% or more, average particle diameter of more than 0.2 ㎛ 20 ㎛. In ₂ O ₃ powder preferably has a purity of more than 99.9% by mass or more, the average particle diameter is more than 0.1 ㎛ 10 ㎛.

(Grinding mixing process S01)

When the sum total content of the metal component in the mixed powder obtained for the said raw material powder is 100 mass%, content of zirconium is 10 mass% or more and 75 mass% or less, and silicon content is 35 mass% or less (but 0 mass % Is not included), and the content of indium is weighed so as to remain in the balance, and pulverized. In this embodiment, pulverization mixing is wet pulverization mixing using the bead mill apparatus which used the zirconia ball of diameter 0.5mm as a grinding media.

In this pulverization mixing process S01, it is pulverized and mixed so that the specific surface area (BET specific surface area) of the mixed powder obtained may be 11.5 m <2> / g or more and 13.5 m <2> / g or less. By using a mixed powder having a specific surface area in the above range, in the sintering step described later, the reactivity with sintering oxygen and the sintering property become high, and a sputtering target having a uniform oxygen concentration, specific resistance, and high sintering density is easily obtained. . On the other hand, when a mixed powder having a specific surface area of less than 11.5 m 2 / g is used, uniform reaction does not occur during firing, and there is a fear that the variation in the oxygen concentration of the sputtering target becomes large. In addition, pulverizing the specific surface area of the mixed powder so as to exceed 13.5 m 2 / g may increase the pulverization mixing time and may be economically disadvantageous.

(Molding process S02)

Next, the mixed powder obtained in the pulverized mixing step S01 is molded into a predetermined shape to obtain a molded body. In this embodiment, it shape | molds using press molding.

(Sintering Process S03)

Next, the molded object shape | molded at shaping | molding process S02 is sintered. In this sintering process S03, the molded object is baked and sintered, introducing oxygen in inside using the baking apparatus provided with the oxygen introduction port. By firing the molded body while introducing oxygen into the firing apparatus, sublimation of the In ₂ O ₃ powder in the mixed powder is suppressed, so that a sputtering target having a uniform oxygen concentration, specific resistance, and high sintered density can be easily obtained. The optimum flow rate of oxygen to be introduced into the firing apparatus varies depending on the contents of the firing apparatus and the conditions such as the size and quantity of the molded article to be sintered. For example, as a reference, the flow rate required for baking 6 or less sheets of a molded article having a diameter of 100 to 300 mm and a thickness of 15 mm or less simultaneously with a firing apparatus having an internal volume of 15000 to 30000 cm 3 is 3 L / min or more and 10 L / min or less. Range. Flow rates above 10 L / min are generally economically undesirable. The gas to be flowed into the calcination apparatus is preferably a volume ratio of oxygen of 100%, that is, pure oxygen, but a gas mixed with other gases such as nitrogen and argon may be used if the volume ratio of oxygen is 80% or more.

As for the holding temperature at the time of baking, the range of 1300 degreeC or more and 1600 degrees C or less is preferable. At the temperature below 1300 degreeC, a sintered compact becomes hard to be compact and there exists a possibility that a density may become low. It is generally economically undesirable to use temperatures in excess of 1600 ° C. for conditional production. 200 degreeC / hour or less is preferable, and, as for the temperature increase rate at the time of baking, the range of 10 degreeC / hour or more and 200 degreeC / hour is more preferable. If it exceeds 200 ° C / hour, it causes uneven reaction, sintering and shrinkage between the raw material powders, which may cause bending and cracking. On the other hand, if it is less than 10 degreeC / hour, time may be too long and productivity may fall.

(Cooling step S04)

Next, the sintered compact obtained by sintering process S03 is cooled. In this cooling step S04, the sintered compact is cooled while introducing oxygen into the firing apparatus until the temperature is at least 600 ° C or lower. By performing cooling of a sintered compact, introducing oxygen into a baking apparatus, the escape | release of oxygen in a sintered compact in cooling is suppressed, and the sputtering target which has uniform oxygen concentration and a specific resistance becomes easy to be obtained. It is preferable to make the flow volume of oxygen introduce | transduced into a baking apparatus the same as the flow volume introduced into a baking apparatus in sintering process S03. Although distribution of oxygen in cooling process S04 is preferable to carry out until taking out a sintered compact, you may stop suitably when the temperature became 600 degrees C or less in consideration of economical efficiency.

200 degreeC / hour or less is preferable, and, as for the cooling rate at the time of cooling until it reaches temperature below 600 degreeC, the range of 1 degreeC / hour or more and 200 degrees C / hour or less is more preferable. When it exceeds 200 degreeC / hour, cooling of a sintered compact will not progress uniformly, the uniformity of oxygen concentration will be impaired, and there exists a possibility that a sintered compact may become easy to crack by thermal stress. On the other hand, if it is less than 1 degree-C / hour, cooling time may be too long and productivity may fall. Although it is preferable that a cooling rate is constant through cooling process S04, you may change suitably during cooling in the range of 200 degrees C / hour or less. Moreover, after cooling to 600 degrees C or less, you may cool at the cooling rate exceeding 200 degreeC / hour, but it is preferable to perform the operation | work which extracts a sintered compact from a baking apparatus at the temperature of 100 degrees C or less.

(Processing step S05)

In the machining step S05, the sintered body cooled in the cooling step S05 is subjected to cutting or grinding, thereby processing into a sputtering target having a predetermined shape.

According to the oxide sputtering target which is this embodiment with the above structure, since the dispersion | variation in the oxidation concentration in a target surface becomes 15% or less, the uniformity of oxygen concentration in a target surface is high, and the specific resistance in a target surface becomes uniform. For this reason, abnormal discharge in sputtering is suppressed and particle generation is suppressed with this.

Further, according to the production process of the oxide sputtering target of the present embodiment, in the grinding mixing step S01, the mixed powder obtained was pulverized mixture of ZrO ₂ powder and SiO ₂ powder and the In ₂ O ₃ powder as a raw material has a specific surface area of Reactivity is high because it is 11.5 m <2> / g or more and 13.5 m <2> / g or less. In addition, in the sintering step S03, firing of the molded body is performed while introducing oxygen into the firing apparatus, and oxygen in the firing atmosphere is not deficient, so that the sintered compact of the molded body becomes uniform and a dense and dense sintered body can be obtained. have. And in cooling process S04, since it cools at the cooling rate of 200 degrees C / hour or less, a sudden temperature change does not occur easily and the oxygen concentration of a sintered compact is stabilized. Therefore, the oxide sputtering target with small dispersion | variation in the oxygen concentration in a target surface can be manufactured stably.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of the invention.

For example, in this embodiment, although the case where the shape of an oxide sputtering target is disk shape was demonstrated, there is no restriction | limiting in particular in the shape of an oxide sputtering target. The oxide sputtering target may be in the form of a square plate. When the shape of an oxide sputtering target is a square plate shape, the measurement point of oxygen concentration and specific resistance can be made into 5 points | pieces of the intersection of a diagonal line and four points of the vicinity of the corner part of each diagonal line.

Moreover, a cylindrical shape may be sufficient as an oxide sputtering target. When the shape of the oxide sputtering target is a cylindrical shape, the measuring points of the oxygen concentration and the specific resistance can be five points in total at equal intervals in the circumferential direction.

Moreover, the oxide sputtering target of this embodiment may contain inevitable impurities. Here, unavoidable impurity means the impurity inevitably contained in raw material powder, and the impurity unavoidably mixed in a manufacturing process.

In addition, according to the production process of the oxide sputtering target of the present embodiment, in the grinding mixing step S01, but the grinding and mixing a ZrO ₂ powder and SiO ₂ powder and the In ₂ O ₃ powder as a raw material, is simply by mixing. However, it is necessary that the specific surface area of the mixed powder obtained by mixing is 11.5 m <2> / g or more and 13.5 m <2> / g or less.

Example

Below, the result of the evaluation test evaluated about the effect of the oxide sputtering target which concerns on this invention is demonstrated.

[Inventive Examples 1-7]

And a raw material powder, the purity is more than 99.9 mass% and an average particle diameter of 2 ㎛ the ZrO ₂ powder, the purity is not less than 99.8 mass%, average particle diameter of 2 ㎛ of SiO ₂ powder, the purity is more than 99.9 mass%, In ₂ O ₃ powder having an average particle diameter of 1 μm was prepared. Each raw material powder prepared was weighed so as to have a molar ratio shown in Table 1, respectively.

Weighed raw material powder was put into the bead mill apparatus using the zirconia ball of diameter 0.5mm as a grinding | pulverization medium, and it grind | pulverized and mixed with a solvent. Nihon Alcohol Sales Co., Ltd. Solmix A-11 was used as the solvent. The time for grinding and mixing was 1 hour. After completion of the grinding and mixing, the zirconia balls were separated and recovered to obtain a slurry containing the raw material powder and the solvent. The obtained slurry was heated, the solvent was removed, and the mixed powder was obtained.

The BET specific surface area of the obtained mixed powder was measured by the specific surface area measuring apparatus (Mountec Co., Macsorb model 1201). The results are shown in Table 1.

Next, the obtained mixed powder was filled into a die having a diameter of 200 mm, and pressed at a pressure of 150 kg / cm 2 to prepare two disc-shaped molded bodies having a diameter of 200 mm and a thickness of 10 mm.

The obtained two molded bodies were put into an electric furnace (furnace content 27000 cm <3>), and it baked and hold | maintained at the baking temperature shown in Table 1 for 7 hours, flowing oxygen in an electric furnace at the flow rate of 4 L per minute, and the sintered compact was produced | generated. Subsequently, the sintered compact is cooled to 600 degreeC at the cooling rate shown in Table 1, continuing to distribute | circulate oxygen in an electric furnace, after that, distribution of oxygen is stopped and cooled by in-warm cooling to room temperature, and then the sintered compact is removed from an electric furnace. It was taken out.

The obtained sintered compact was machined to obtain two disc-shaped sputtering targets having a diameter of 152.4 mm and a thickness of 6 mm.

Comparative Example 1

Except having mixed the measured raw material powder with the Henschel mixer, it carried out similarly to the example 1 of this invention, and produced two sputtering targets.

Comparative Example 2

Two sputtering targets were produced like Example 1 of this invention except the cooling rate of the sintered compact to 600 degreeC being 250 degreeC / hour.

Comparative Example 3

At the time of baking of a molded object, two sputtering targets were produced like Example 1 of this invention except not having flowed oxygen into an electric furnace.

[Comparative Example 4]

Two sputtering targets were manufactured like Example 1 of this invention except the baking temperature of the sintered compact was 1250 degreeC.

[evaluation]

The metal component composition, relative density, oxygen content, and specific resistance of the sputtering target were measured. Moreover, the sputter test of the sputtering target was performed.

One of the two produced sputtering targets was used for the measurement of a relative density, a specific resistance, and oxygen content, and the other one was used for the sputter test. In the sputtering test, first, the number of occurrences of abnormal discharges during sputtering was measured. Subsequently, after forming an oxide film with the sputter | spatter, the presence or absence of the crack of a target was confirmed. In addition, the indium concentration in the oxide film formed into a film was measured.

Each evaluation method is as follows.

(Metal Component Composition of Sputtering Target)

A part of the edge part of the sintered compact before machining with a sputtering target was taken as a sample. The sample collected was dissolved in an acid, and the composition of the resulting solution was analyzed by an Agilent Technologies Inductively Coupled Plasma Emission Spectroscopy (ICP-OES) apparatus (Agilent 5100), and the metal component compositions of Zr, Si, and In were analyzed. The measurement results are shown in Table 2.

(Relative density)

The relative density was calculated as the ratio of the measured density to the theoretical density (measured density / theoretical density × 100). The measurement density was calculated | required by measuring the weight and dimension of a sputtering target. The theoretical density was computed from the density | concentration and density of each oxide contained in a sputtering target. Specifically, the mass% concentration of ZrO ₂ is C1, the density is ρ1, the mass% concentration of SiO ₂ is C2, the density is ρ2, and the mass% concentration of In ₂ O ₃ is C3, the density is ρ3. , The theoretical density (ρ) was calculated by the following formula.

ρ = 1 / [C1 / 100ρ1 + C2 / 100ρ2 + C3 / 100ρ3]

Here, values of p1 = 5.60 g / cm3, p2 = 2.20 g / cm3 and p3 = 7.18 g / cm3 were used. In addition, C1, C2, C3 was computed from the compounding quantity of raw material powder.

(Resistance)

The specific resistance was measured by the four probe method. In order to measure the variation of a specific resistance, as shown in FIG. 1, the center point 1 of a target surface (circle) and two linear forms orthogonal to each other at the center point of a target surface, and are located in the position of 20 mm from an outer edge It measured at five points in total of four points (2)-(5). The maximum value and minimum value of the measured specific resistances were extracted, and the deviation of specific resistance was computed by said Formula (2). In Table 2, the measured value and the deviation of the specific resistance at each measuring point are shown.

(Oxygen concentration)

As shown in FIG. 1, the four points (2)-(5) which are two straight lines orthogonal to each other at the center point 1 of the target surface (circle) and the center point of the target surface, and are located at 20 mm from the outer edge. 10 mm in width and width were cut out as a sample piece for oxygen concentration measurement from 5 points in total, and the oxygen concentration of the surface (target surface) of the sample for oxygen concentration measurement was measured as follows.

First, the sample for oxygen concentration measurement was filled with resin, and the surface (target surface) of the oxygen concentration measurement sample piece which filled resin was mirror-polished with the grinding | polishing apparatus. And after polishing, the oxygen concentration of the polishing surface was quantitatively analyzed by EPMA (Nihon Electronics Co., JXA-8500F). The quantitative analysis conditions of oxygen by EPMA were as follows.

Acceleration Voltage: 15 ㎸

Irradiation Current: 5 × 10 ^-8 A

Beam diameter: 100 μm

In addition, the spectral crystal used in the quantitative analysis of oxygen is LDE1.

The measurement was performed about 10 places randomly among the sample pieces of 10 mm in width and width, and the average value was made into the measured value of the oxygen concentration of one point shown in FIG.

The maximum value and minimum value of five measured oxygen concentrations shown in FIG. 1 were extracted, and the deviation of oxygen concentration was computed by said Formula (1). In Table 2, the measured value and the deviation of the oxygen concentration of each oxygen concentration measurement sample are shown.

(Sputter test)

The sputtering target was soldered to a backing plate made of oxygen-free copper, and was mounted in a magnetron type sputtering device (SIH-450H, manufactured by ULVAC). Then, after exhausting the inside of a sputtering apparatus with a vacuum exhaust system to not higher than 5 × 10 ^-5 Pa, introducing Ar gas and O ₂ gas, and adjust the sputtering gas pressure to 0.67 Pa, subjected to a pre-sputtered for one hour, Thereby, the processed layer of the target surface was removed. At this time, the flow rate ratio of Ar gas and O ₂ gas was 47 to 3, the power was pulsed at 1000 W, the pulse condition was frequency of 50 kHz, and the duty ratio was 0.08.

(Number of abnormal discharges)

Continuous sputtering for 1 hour was performed under the same conditions as the above-mentioned sputtering. The frequency | count of abnormal discharge which generate | occur | produced during this 1 hour was measured using the arcing count function provided with the DC power supply of the used sputtering apparatus. The results are shown in Table 3.

(Film Formation of Oxide Film and Composition Analysis of Oxide Film)

After the measurement of the number of abnormal discharges, a polycarbonate substrate having a size of 20 mm in width and width on a Si substrate having a diameter of 6 inches was shown at 5 points (1 point of Si substrate center and 4 parts of 60 mm radius from the center) shown in FIG. 3. After preparing, the sputtering apparatus was loaded, it was stopped in the target directly, and the inside of the sputtering apparatus was exhausted to 5x10 <^-5> Pa or less with a vacuum exhaust apparatus, and sputtering was carried out under the same conditions as the said presputter. The oxide film of thickness 200nm was formed on the board | substrate. The distance of the board | substrate and a target at this time was 70 mm. The composition of the solution obtained by dissolving each obtained oxide film with an acid was analyzed by an Agilent Technologies Inductively Coupled Plasma Emission Spectroscopy (ICP-OES) device (Agilent 5100) to measure the In concentration in each oxide film, and the deviation was It calculated from Formula (3). In Table 3, the measured value and the deviation of the In concentration (mass% when the total content of the metal element is 100) in the oxide film are shown.

Equation (3):

Deviation (%) of In concentration of oxide film = [(maximum value of In concentration)-(minimum value of In concentration)] / [(maximum value of In concentration) + (minimum value of In concentration)] × 100

(With or without crack)

After the formation of the oxide film, the sputtering apparatus was opened to the atmosphere. And the sputtering target was taken out from the sputter apparatus, the external appearance was observed visually, and the presence or absence of the crack was confirmed. The results are shown in Table 3.

BET specific surface area of the mixed powder of the raw material powder is less than 11.5 m 2 / g, Comparative Example 1, Comparative Example 2, the cooling rate to 600 ℃ of the sintered body exceeds 200 ℃ / time, the molded body is fired without flowing oxygen into the firing apparatus As for the sputtering target obtained also in any one of comparative example 3 and the comparative example 4 whose baking temperature of a molded object is less than 1300 degreeC, the dispersion | variation in the oxygen concentration in a target surface exceeded 15%.

In the sputtering targets of Comparative Examples 1 to 4 in which the variation in the oxygen concentration in the target surface exceeded 15%, the variation in the specific resistance increased to 15% or more, and the number of abnormal discharges during sputtering increased. In addition, the variation in In concentration of the oxide film formed by sputtering was large. In particular, cracks occurred in the sputtering targets of Comparative Examples 2 and 4 after the sputtering.

In contrast, the BET specific surface area of the mixed powder of the raw material powder is in the range of 11.5 m 2 / g or more and 13.5 m 2 / g or less, the cooling rate to 600 ° C. of the sintered body is 200 ° C./hour or less, and the molded body is brought into the firing apparatus. The sputtering targets of Examples 1 to 7 of the present invention fired at a temperature of 1300 ° C or more and 1600 ° C or less while circulating oxygen were all 15% or less in the variation in oxygen concentration in the target surface.

As for the sputtering targets of Examples 1-7 of this invention which the deviation of the oxygen concentration in a target surface is 15% or less, the variation of a specific resistance all became 15% or less, and the frequency | count of abnormal discharge during sputtering was remarkably reduced. In addition, in the oxide film formed by sputtering, variation in In concentration was reduced. In addition, no crack occurred after sputtering.

From the above evaluation test results, it was confirmed that according to the example of the present invention, it is possible to provide an oxide sputtering target capable of suppressing occurrence of abnormal discharge during sputtering and scattering of particles, and a method for producing the oxide sputtering target.

Claims (3)

An oxide sputtering target consisting of an oxide containing zirconium, silicon, and indium as a metal component, wherein the ratio of the difference between the maximum and minimum values of the oxygen concentration relative to the sum of the maximum and minimum values of the oxygen concentration in the target surface is 15% or less. Oxide sputtering target to be. The method of claim 1,
The ratio of the difference of the maximum value and minimum value of the specific resistance with respect to the sum total of the maximum value and minimum value of the specific resistance in a target surface is 15% or less, The oxide sputtering target characterized by the above-mentioned. As a method of manufacturing the oxide sputtering target according to claim 1 or 2,
Mixing zirconium oxide powder, silicon dioxide powder and indium oxide powder to obtain a mixed powder having a specific surface area of at least 11.5 m 2 / g and at most 13.5 m 2 / g,
Molding the mixed powder to obtain a molded body,
Baking the molded body at a temperature of 1300 ° C. or higher and 1600 ° C. or lower while circulating oxygen into the sintering apparatus to produce a sintered body,
And a step of cooling the sintered body to a temperature of at least 600 ° C. or less at a cooling rate of 200 ° C./hour or less while flowing oxygen into the firing apparatus.

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