KR101138700B1 - Sno-based sputtering target - Google Patents

Abstract

By reducing the film stress of the sputter film to an absolute value, a SnO ₂ based sintered compact target having low film peeling from the surrounding structure of the sputter cathode is provided. This SnO ₂ -based sputtering target includes Sb ₂ O ₃ of more than 10 ppm and less than 1 mass%, Ta ₂ O ₅ and / or Nb ₂ O ₅ having a total mass of 20 mass% or less, SnO ₂ as the remainder and inevitable. It consists of a sintered compact which consists of impurities.

SnO2-based sputtering target, sputter cathode

Description

SnO2-based sputtering target {SNO-BASED SPUTTERING TARGET}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a SnO ₂ -based sputtering target, specifically, in various applications such as flat panel displays, touch panels, solar cells, and the like, various films such as transparent electrodes, antistatic, electromagnetic shielding, gas barriers, and hot ray reflections. The present invention relates to a SnO ₂ -based sputtering target used for securing a function.

In recent years, SnO ₂ -based thin films are used in a wide range of applications, such as flat panel displays, touch panels, and solar cells. This SnO ₂ based thin film is mainly produced industrially by a spray method or a CVD method. However, these methods are not suitable for uniformizing the film thickness to a large area, are difficult to control the film forming process, and also generate high temperature or produce chlorine-based gas which is a contaminant during film formation. There is a need for a new manufacturing method without this.

On the other hand, the manufacture of SnO _{2 type} thin film by sputtering method is also tried, As a sputtering target for this, the SnO ₂ -Sb ₂ O ₃ target to which Sb ₂ O ₃ was added in order to reduce the specific resistance of a target is industrially utilized only. It is. However, in the conventional SnO ₂ -based sintered compact target, when the film deposition amount increases with increasing integration power, a lot of particles due to film peeling from the surrounding structure of the sputter cathode tended to occur. It is also known that if particles adhere to the thin film, the thin film may deteriorate its performance and cause thin film defects. For this reason, at the time of sputtering, the SnO _{2 type} sputtering target with little film peeling from a surrounding structure is calculated | required.

As a material of the SnO ₂ -Sb ₂ O ₃ system, for it is proposed to the following example. The total amount of not more than 20% by mass in terms of oxides of Nb or, Nb and Ta, and incidental (不可避的) impurities formed as by Sb ₂ O ₃ and a remainder (殘部) SnO ₂ of 10ppm or less, a sintered at more than 1450 ℃ Sintered bodies are known (see, for example, Japanese Patent No. 3955917). Also, a one SnO ₂ -Sb ₂ O ₃ sintered body sintered at, below 820 ℃ containing Sb ₂ O ₃ of 10.2% by weight is known (for example, see Japanese Patent No. 3662168 gazette). In addition, a tin oxide-antioxidant monoantimony sintered compact target sintered at 800 ° C. containing 3 to 10% by mass of Sb ₂ O ₃ and the balance of which is composed of SnO ₂ and unavoidable impurities is known (for example, Japanese Patent No. See publication 3710021). Further, a tin sintered at 1500 ℃ consisting of 6% by mass of antimony oxide and 5 to 20% by weight of zinc oxide and a remainder of SnO ₂ - there is an antimony oxide sintered body target is known (e.g., Japanese Patent Laid-Open 2003-73819 See the Gazette publication. However, in any of these documents, it is made of a sintered body containing more than 10 ppm and less than 1% by mass of Sb ₂ O ₃ , the film stress of the sputter film is small in absolute value, and the film peeling from the peripheral structure of the sputter cathode at the time of sputtering. Little is known about the SnO ₂ -based sputtering target.

[Initiation of invention]

The present inventors, at this time, specify the amount of Sb ₂ O ₃ added in the SnO ₂ -based sputtering target to more than 10 ppm and less than 1 mass%, and when the obtained SnO ₂ -based sintered compact is used as the sputtering target, the sputter film having a small film stress at an absolute value is obtained. It was obtained and found that the film peeling from the surrounding structure of the sputtering cathode was small at the time of sputtering.

Accordingly, an object of the present invention is to provide a sintered body comprising Sb ₂ O ₃ of more than 10 ppm and less than 1% by mass, in which the film stress of the sputtering film is small in absolute value and the film peeling from the surrounding structure of the sputtering cathode is small during sputtering. It is providing the SnO _{2 type} sintered compact target which consists of.

That is, the SnO ₂ -based sputtering target according to the present invention includes Sb ₂ O ₃ of more than 10 ppm and less than 1 mass%, Ta ₂ O ₅ and / or Nb ₂ O ₅ having a total mass of 20 mass% or less, and SnO ₂ as the remainder. And a sintered body made of unavoidable impurities.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic schematic diagram of the sputtering apparatus used for evaluation of film peeling.

BEST MODE FOR CARRYING OUT THE INVENTION [

SnO _2- based sputtering target

The SnO ₂ -based sputtering target according to the present invention is Sb ₂ O ₃ of more than 10 ppm and less than 1% by mass, Ta ₂ O ₅ and / or Nb ₂ O ₅ with a total mass of preferably 1 to 20% by mass, and the remainder as it composed of a sintered body made of SnO ₂ and inevitable impurities. When such a SnO ₂ based sintered compact is used as the sputtering target, a sputtered film having a small film stress at an absolute value can be obtained, and the film peeling from the surrounding structure of the sputtering cathode can be reduced during sputtering.

According to a preferred aspect of the present invention, the content of Sb ₂ O ₃ is that the 11 ~ and 9000ppm, more preferably 100 ~ 6000ppm, more preferably 300 ~ 2000ppm. In sputtering using the sputtering target which consists of a sintered compact in this composition range, the film stress of the sputtering film obtained can be made smaller in absolute value, and the film peeling from the peripheral structure of a sputtering cathode can be reduced at the time of sputtering.

According to an exemplary embodiment of the present invention, the content of Ta ₂ O ₅ is preferably from 0 to 15% by mass and the content of Nb ₂ O ₅ is preferably from 0 to 15% by weight. By using the raw material mixed powder in this composition range, a sintered compact can be manufactured by the cold press method and the injection method which can manufacture a comparatively large sized sintered compact, and also sintering can be performed in high temperature conditions of 1300 degreeC or more. have.

According to a preferable aspect of the present invention, the sputtering target according to the present invention is preferably made of a sintered body sintered at 1300 ° C or higher, more preferably 1350 to 1650 ° C, still more preferably 1500 to 1650 ° C. In the sintered body sintered in this temperature range, liquid phase sintering sufficiently advances, and a sintered compact with high sintered density can be obtained.

According to a preferred aspect of the present invention, the sputtering target according to the present invention preferably comprises a sintered body having a relative density of 60% or more, more preferably 75% or more, and still more preferably 95% or more. Within this relative density range, the film formation speed during sputtering can be increased, the service life of the target can be extended, and arcing during sputtering can be reduced. Moreover, when sintering density becomes high, the bubble etc. in a sintered compact can be reduced.

According to a preferred aspect of the present invention, when the sputtering target according to the present invention is used for sputtering, it is preferable to obtain a sputtering film having an absolute value of film stress of 1050 MPa or less, more preferably 1000 MPa or less. Within this film stress value range, film peeling from the surrounding structure of the sputtering cathode is small, and generation of particles due to film peeling can be suppressed.

Manufacturing method of SnO ₂ -based sputtering target

Production method of SnO ₂ based sputtering target according to the present invention is not particularly limited, it can be performed according to the preferred embodiment described below. That is, according to a preferable aspect of the present invention, first, SnO ₂ is used as a main component, Sb ₂ O ₃ is contained in an amount of more than 10 ppm and less than 1 mass%, and 20 masses of Ta ₂ O ₅ and / or Nb ₂ O ₅ are present in the total mass. An unsintered molded body containing% or less is prepared. In the present invention, the molded article of the microcrystal may be molded by any method as long as the raw powder containing the composition is molded. For example, SnO ₂ powder, Sb ₂ O ₃ powder, Ta ₂ O ₅ powder, and Nb. mix ₂ O ₅ powder ratio of the amount satisfying the above composition to prepare a raw meal, and can be produced by molding the raw meal.

According to the preferable aspect of this invention, it is preferable that the molded object of the green body using a raw material powder makes it easy to provide a predetermined shape by adding a binder to a raw material powder. As such a binder, it is not limited, if it is a well-known binder which loses | disappears and scatters by heating, Polyvinyl alcohol aqueous solution etc. can be used. Although the method of drying and a heating is not limited, First, it is preferable to dry at 50-130 degreeC for 5 to 30 hours, and to carry out degreasing by heating at 500-800 degreeC for 6 to 24 hours next.

According to the preferable aspect of this invention, it is preferable to sinter the green body molded product prepared as mentioned above at 1300 degreeC or more, More preferably, it is 1350-1650 degreeC, More preferably, it is 1500-1650 degreeC. By performing the sintering in the temperature range, it is possible to increase the sintered density to the liquid phase sintering proceeds sufficiently, and also, it is possible to prevent melting of SnO ₂ can easily carry out the production of the sintered body having a desired shape.

According to a preferable aspect of the present invention, the sintering is preferably performed for 2 to 20 hours, more preferably 3 to 12 hours, still more preferably 4 to 8 hours. If it is in this range, sintering can fully be carried out, suppressing an electric power consumption amount and ensuring high productivity.

According to a preferred aspect of the present invention, the sintering is preferably performed under an oxygen-containing atmosphere in order to secure a high sintered density. For example, the sintering can be performed under an oxygen pressurized atmosphere, under an oxygen atmosphere, or under an atmospheric atmosphere.

[Examples 1 ～ 37]

(1) Preparation of Sputtering Target

First, the following four types of raw material powders were prepared.

SnO ₂ powder: Purity 99.99% (4N), Average particle size 0.7 ~ 1.1㎛, Specific surface area 2.0 ~ 2.7m ² / g

Ta ₂ O ₅ powder: Purity 99.9% (3N), average particle size 0.6 ~ 0.8㎛, specific surface area 2.0 ~ 3.1m ² / g

Nb ₂ O ₅ powder: Purity 99.9% (3N), average particle diameter 0.6 ~ 1.0㎛, specific surface area 2.1∼2.7m ² / g

Sb ₂ O ₃ powder: purity 99.9% (3N), average particle size 0.6∼1.0㎛,

For each example, the four kinds of raw material powders were weighed and mixed for 21 hours in a dry ball mill. The polyvinyl alcohol aqueous solution was added to this mixed powder, and after fully mixing, it filled into the metal mold | die of 400 * 800mm dimension, and press-molded at the pressure of 800 kgf / cm <^2> . This molded product was dried at 80 ° C for 12 hours. This dried body was baked for 8 hours at the baking temperature shown in Table 1 in oxygen atmosphere, and the sintered compact was obtained. At this time, the temperature increase rate was 400 degreeC / hour, and the temperature-fall rate was controlled at 100 degreeC / hour. The resulting sintered compact was machined to a size of 152.4 mm in diameter and 5 mm in thickness to obtain a SnO ₂ -based sputtering target. In addition, the processed cutting material of the sintered compact is ground using a mortar, and hydrolyzed by adding the ground powder, mixed acid of nitric acid and hydrochloric acid, and ultrapure water to a container made of Teflon (registered trademark). It was set as the fixed solution. The measurement of each element of Ta, Nb, and Sb in the obtained fixed solution was performed by ICP mass spectrometry using the ICP mass spectrometer (4500 by Agilent). Table 1 shows the oxide equivalents.

(2) evaluation

The various evaluation tests shown below were done about the obtained sputtering target.

Evaluation 1: Measurement of Relative Density

The relative density of each sputtering target was measured by the Archimedes method. At this time, the density of each material ^{_{SnO 2: 6.95g / cm 3,}} Ta 2 O 5: 8.74g / cm 3, Nb 2 O 5: Due to 4.47g / cm ^3, and calculates the weighted average density (theoretical density) The relative density was calculated by making the weighted average density 100%. The result was as having shown in Table 1.

Evaluation 2: Evaluation of Film Stress of Sputter Film

The sputtering target obtained in Examples 1-37 was metal-bonded to the bucking plate made of oxygen-free copper. Then, sputtering using a DC power supply was performed on each metal-bonded sputtering target under the sputtering conditions shown below, and sputter film deposition was performed on the silicon wafer.

Cathode: magnetic field magnetic circuit

Target / Board Distance: 50mm

Sputtering chamber attainment pressure: <1 × 10 ^-4 Pa

Substrate temperature: Room temperature (no heating)

Introductory gas: Argon + oxygen (oxygen concentration 1% by volume)

Inlet gas partial pressure: 0.67Pa

DC applied power: 360W

Film thickness: 500nm

Substrate: Φ4inch × 525㎛ Silicon Wafer

About the sputter film obtained in this way, the curvature radius was measured using FLX-2320-5 (made by Tomei Technologies Co., Ltd.), and the stress was computed using the following formula. The negative sign of the film stress indicates that it is a compressive stress.

σ = Eb ² / {6 (1-ν) * rd}

σ: stress

E: Young's modulus of the substrate

b: thickness of the substrate

ν: Poisson's ratio of the substrate

d: film thickness

r: radius of curvature of the substrate after film formation (measured by the Newton method)

The results are as shown in Table 1, and it can be seen that any of the sputtered films formed by using the sputtering target that satisfies the composition of the present invention has a low film stress.

Evaluation 3: Evaluation of Membrane Peeling

The sputtering target obtained in Examples 1-37 was evaluated as follows using the sputtering apparatus shown in FIG. 1 as follows. The sputtering apparatus shown in FIG. 1 is provided with the bucking plate 3 in which the target 2 is mounted, and the board | substrate holder 4 provided in the chamber 1 facing the bucking plate 3. It is done by In the chamber 1, an earth shield 5 for protecting the side surfaces of the target 2 and the bucking plate 3, and an adhesion plate 6 for preventing the formation of a film on the chamber 1 are also provided. .

First, each sputtering target was metal-bonded to the bucking plate 3 in the chamber 1. And the target 2 metal-bonded was continuously discharged in the sputter | spatter conditions shown below. After the continuous discharge, the films attached to the substrate holder 4, the earth shield 5, and the anti-deposition plate 6 were observed, so that the films were apparently separated from each other, and X was not.

Cathode: magnetic field magnetic circuit

Sputtering chamber attainment pressure: <1 × 10 ^-4 Pa

Introductory gas: Argon + oxygen (oxygen concentration 1% by volume)

Inlet gas partial pressure: 0.67Pa

DC applied power: 360W

Film thickness: 500nm

Sputter time: continuous 30hr discharge

Earth Shield: Alundum # 60 blasted product

Board Holder: Alundom # 60 blasted product

Anti-rust board: Alundom # 60 blasted product

The results are as shown in Table 1, and after continuous discharge using a sputtering target that satisfies the composition of the present invention, they are attached to the substrate holder 4, the earth shield 5, and the adhesion plate 6 shown in FIG. It can be seen that none of the membranes causes membrane detachment.

[Table 1]

Claims (5)

Sb ₂ O ₃ of more than 10 ppm and less than 1% by mass, Ta ₂ O ₅ or Nb ₂ O _{5 of} 1-20% by mass, or Ta ₂ O ₅ and Nb ₂ O ₅ having a total mass of 1-20% by mass, balance (殘部) as SnO ₂ and inevitable (不可避) impurities formed of a sintered body made of, SnO ₂ based sputtering target. The method of claim 1, When the content of Sb ₂ O ₃ 11 ~ 9000ppm of a sputtering target. The method of claim 1, A sputtering target content of Sb ₂ O ₃ is 100 ~ 6000ppm. The method of claim 1, A sputtering target when the content of Sb ₂ O ₃ 300 ~ 2000ppm. The method according to any one of claims 1 to 4, If the content of Ta ₂ O ₅ 1 ~ 15% by weight, and also a sputtering target when the content of Nb ₂ O ₅ 1 ~ 15% by weight.

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