JP2001262326A - Indium oxide-metallic thin powder mixture, ito sputtering target using the same powdery mixture as raw material and method for producing the same target - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an indium oxide-metallic tin powdery mixture at a low cost, from which a sintered body of high density in which tin components are entered into solid solution in indium oxide, not present in the form of thin oxide and suitable for depositing an ITO film of high quality is obtained and to suppress nodules generated on a target and to reduce abnormal discharge and particles in the process of film deposition by sputtering by using an ITO sputtering target obtained by performing sintering using the same powder mixture. SOLUTION: This ITO sputtering target is obtained by pulverizing a powdery mixture composed of metal thin powder with the average particle size of 1 to 100 μm, and the balance indium oxide powder, thereafter performing granulation, molding the same at ordinary temperature under the pressure of 700 to 3,000 kg/cm2 and sintering this molded body at 1,500 to 1,650 deg.C in an oxygen atmosphere or in the air, and its producing method is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an indium oxide-metal tin mixed powder, an ITO sputtering target using indium oxide-metal tin mixed powder as a raw material, and a method of manufacturing the same.

[0002]

2. Description of the Related Art ITO (indium-tin composite oxide)
The film is widely used as a transparent electrode (film) of a display device mainly for a liquid crystal display. The method of forming the ITO film is generally performed by a means generally called a physical vapor deposition method such as a vacuum vapor deposition method or a sputtering method. In particular, it is often formed using a magnetron sputtering method from the viewpoint of operability and stability of the film.

[0003] The formation of a film by the sputtering method involves physically colliding positive ions, such as Ar ions, with a target provided on a cathode, and releasing the material constituting the target with the collision energy, thereby forming a film on the side of the anode facing the anode. By laminating a film having substantially the same composition as the target material on the substrate. The coating method by the sputtering method has a feature that a thin film having a thickness of several nm to a thick film having a thickness of several tens of μm can be formed at a stable film forming rate by adjusting the processing time, the supplied power, and the like.

In general, in order to obtain an ITO film of high quality, it is necessary to obtain a high-density ITO component in which the tin component in the sintered body forms a solid solution in indium oxide and does not exist in the form of tin oxide.
It is necessary to perform sputtering using a target. If the density of the target is low or the tin component in the sintered body is not sufficiently dissolved in indium oxide, black projections called nodules frequently occur on the erosion surface of the target during sputtering. As a result, sputtering becomes unstable, and abnormal discharge and particles generated at that time frequently cause film defects such as film hole defects and protrusions on the film. Therefore, as a method of manufacturing a high-density ITO target, it has been proposed to include a metal indium powder or an indium tin alloy powder in a raw material powder (Japanese Patent Laid-Open No. 2-144959). Body density is at most 5.3 g / cm
³ , which was not sufficient in terms of performance.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, and is particularly suitable for forming a high quality ITO film. And an indium oxide-metal tin mixed powder capable of obtaining a sintered body not existing in the form of tin oxide, and an ITO sputtering target sintered using the mixed powder. It is an object of the present invention to suppress nodules generated in a target during film formation and reduce abnormal discharge and particles.

[0006]

A technical means for solving the above problems is to use a mixed powder of indium oxide and metal tin as a raw material for an ITO target, thereby forming a high quality ITO film. That a suitable ITO sputtering target can be obtained. Based on this finding, the present invention provides: 1) an indium oxide-metal tin mixed powder comprising an indium oxide powder and a metal tin powder having an average particle diameter of 1 to 100 μm 2) an average particle diameter of the metal tin powder of 10 to 10 μm 3. Indium oxide-metal tin mixed powder as described in 1 above, characterized in that it is 40 μm. 3) Indium oxide-metal tin mixed as described in 1 or 2 above, wherein the maximum particle size of the metal tin powder does not exceed 150 μm. Powder 4) After finely pulverizing the indium oxide-metal tin mixed powder,
Indium oxide-metal tin mixed powder according to any one of the above 1 to 3, characterized in that granulation is performed. 5) A mixed powder composed of indium oxide powder and metal tin powder having an average particle diameter of 1 to 100 µm is molded and then sintered. An ITO sputtering target made of indium oxide-metal tin mixed powder, characterized in that the sintered body does not contain metal tin. 6) An average particle diameter of the metal tin powder is 10 to 40 μm. 7) The ITO sputtering target according to 5 or 6 above, wherein the maximum particle diameter of the metal tin powder does not exceed 150 μm. 8) The indium oxide-metal tin mixed powder is finely pulverized. rear,
9) The ITO sputtering target according to any one of 5 to 7 above, wherein the density of the sintered body is 6.8 g / cm ³ or more. 10) Indium oxide-metal tin mixed powder containing 0.78 to 11.82 wt% of metal tin powder is pulverized and then granulated, and then granulated at normal temperature under a pressure of 700 to 3000 kg / cm ^2.
A method of manufacturing an ITO sputtering target characterized by heating and sintering at 1500 to 1650 ° C. in an oxygen atmosphere or air after the lower mold or CIP molding 11) Metal tin is contained in the sintered body (12) The method for producing an ITO sputtering target according to (10) or (11), wherein the density of the sintered body is 6.8 g / cm ³ or more. 13) The method for producing an ITO sputtering target according to any one of the above items 10 to 12, wherein the mixed powder is an indium oxide-metal tin mixed powder composed of indium oxide powder and metal tin powder having an average particle diameter of 1 to 100 μm. Each of the above-mentioned 10 to 13, wherein the average particle diameter of the tin powder is 10 to 40 µm IT described
15) The method according to any one of the items 10 to 14, wherein the maximum particle size of the metal tin powder does not exceed 150 μm.
16) The method for producing an ITO sputtering target according to any one of the above items 10 to 15, wherein the mixed powder of indium oxide and metal tin is finely pulverized and then granulated.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In general, a mixed powder of indium oxide and tin oxide is often used as a raw material for an ITO sputtering target. It was unavoidable that the tin component in the solid was not completely dissolved in indium oxide and a part of the tin component was present in the form of tin oxide. In addition, in order to improve the solid solubility of the tin oxide component and obtain a high-density target, indium oxide powder and tin oxide powder as raw materials and a powder mixture thereof are refined to an average particle size of about several μm, and the particle size is reduced. The distribution also needed to be strictly adjusted and managed. The present invention has successfully solved the above-mentioned problem by using indium oxide-metal tin mixed powder as a raw material for an ITO target.

[0008] As described above, the present invention provides an average particle size of 1 to 10
0.78 to 11.82 wt% of 0 µm metal tin powder and the particle size of the powder reaching 95% below the sieve is 1.5 to 2.5.
A mixed powder of μm indium oxide powder is used as a raw material of the ITO target. The average particle size of the metal tin powder is 10
４０40 μm, and the maximum particle size is 1
It is desirable not to exceed 50 μm. Indium oxide-
Since the metal tin is active, the metal tin mixed powder is 1 to 1
It has a feature that the tin component (metal tin) is sufficiently dissolved in indium oxide during sintering even in a wide range of average particle diameter of 100 μm. When using indium oxide-tin oxide mixed powder as a raw material, this is a marked difference as compared with the case where each powder had to be adjusted to an average particle size of about several μm. Further, the present invention has a remarkable advantage that the step of producing a fine powder of tin oxide, which is conventionally essential, is eliminated, and the production cost can be greatly reduced. In addition, there is an advantage that treatment of acidic wastewater generated in the tin oxide powder production process is unnecessary.

In the production of a sintered body, the above-mentioned metal tin powder and indium oxide powder are first mixed and finely pulverized using a wet mill or the like to an average particle size of about 1 μm. This finely pulverized slurry is granulated to obtain granulated powder having an average particle diameter of 45 μm, for example.
Next, this is filled in a mold or a CIP mold, and the pressure is 7 at room temperature.
Molding is performed at a pressure of 00 to 3000 kg / cm ² . The density of this molded body is about ³ to 4 g / cm ³ . The molded body is sintered at 1500 to 1650 ° C. in an oxygen atmosphere (the “oxygen atmosphere” used in this specification means a high oxygen partial pressure atmosphere including a pure oxygen atmosphere) or the atmosphere. I do. The heating time is about 4 to 9 hours, and the holding time is 0 to 7
About an hour. This results in a density of 6.8 g / cm.
^Three or more high-density sintered bodies can be obtained. In addition, despite the use of tin metal, the sintered body does not contain tin metal. This is a major feature of the present invention. The sintered body is further subjected to machining, adjustment of surface roughness, bonding to a backing plate, finishing, washing, and the like to obtain an ITO sputtering target.

[0010]

Examples and Comparative Examples Next, examples of the present invention will be described. This embodiment is merely an example, and the present invention is not limited to this example. That is, all aspects or modifications other than the examples are included within the scope of the technical idea of the present invention.

(Example) As a raw material powder for sintering, 7.88 w of metal tin powder having an average particle size of 40 μm and a maximum particle size of 100 μm.
Indium oxide powder having t% and a balance average particle diameter of 2 μm was used. Next, the metal tin powder and the indium oxide powder were mixed and finely pulverized using a wet mill to an average particle size of 0.9 μm. This finely pulverized slurry was granulated to obtain granulated powder having an average particle diameter of 45 μm. Next, this is 179 mm in width and 788 in length.
750k at room temperature by hydraulic press
It was molded under a pressure of g / cm ² . The density of the molded product thus obtained was 3.78 g / cm ³ .

The molded body was sintered in a pure oxygen atmosphere for 6 hours at a heating time of 1570 ° C. and a holding time of 4 hours. Thereby, the density of the sintered body is 7.13 g / cm.
³ was obtained. X-ray diffraction of this sintered body was confirmed for metallic tin. However, despite the use of metallic tin as a raw material powder, this sintered body did not contain metallic tin. This sintered body was further processed to 127 × 508 × 6 mm by machining, and after bonding to a backing plate, surface roughness Ra =
The thickness was adjusted to 0.35 μm, and multiple ultrasonic cleaning was performed to obtain an ITO sputtering target.

Comparative Example As a raw material powder for sintering, 10.00 wt% of tin oxide powder having an average particle size of 2 μm and a residual average particle size of 2
μm indium oxide powder was used. Next, the tin oxide powder and the indium oxide powder were mixed and pulverized to a mean particle size of 0.9 μm using a wet mill. This finely pulverized slurry was granulated to obtain granulated powder having an average particle diameter of 45 μm. next,
This is filled in a mold of width 179 mm and length 788 mm,
Molding was performed by applying a pressure of 750 kg / cm ^{2 at} normal temperature by a hydraulic press. The density of the molded product thus obtained was 3.72 g / cm ³ .

The molded body was sintered in a pure oxygen atmosphere with a heating time of 6 hours, heating at 1570 ° C. and a holding time of 4 hours. Thereby, the density of the sintered body is 7.11 g / cm.
³ was obtained. This sintered body is further processed to 127 × 508 × 6 mm by machining, and after bonding to a backing plate, is adjusted to a surface roughness Ra = 0.35 μm by finishing, and further subjected to multiple ultrasonic cleaning and the like. An ITO sputtering target was used. As a result, the tin oxide-indium oxide mixed powder of the comparative example is:
Even when a fine powder (tin oxide powder having an average particle size of 2 μm) was used, the result was slightly inferior to the sintered body density of the example.

Next, DC magnetron sputtering was performed using the sputtering targets obtained in the above Examples and Comparative Examples, and the generation amount (coverage) of nodules and the number of arc discharges were measured. The sputtering conditions are as follows. Sputtering gas: Ar + _{0 2} sputtering gas pressure: 0.5 Pa Sputtering gas flow rate: 300 SCCM oxygen concentration of the sputtering gas: 1 vol% leakage magnetic flux density: 1000 Gauss turned sputtering power density: 1.0 W / cm ² of nodules coverage measurement results and Table 1 shows the results of measuring the number of abnormal discharges generated by the micro arc monitor. Here, the “nodule coverage” is a percentage of “nodule area / erosion area” on the surface of the sputtering target.

The nodule coverage rate is 20 WH
At r / cm ² , the example is 0.3%,
In the comparative example was 0.5%, the same 40WHr / cm ^2, whereas the embodiment is 2.2%, 2.8% in the comparative example, the further the 120WHr / cm ^2,
In the example, 39.5% was obtained, whereas in the comparative example, 4% was obtained.
9.1%. The number of abnormal discharge occurrences is
At 0 WHr / cm ² , the number of examples was 9 times, whereas in the comparative example, it was 16 times. At 40 WHr / cm ² , the number of examples was 21 times, whereas that of the comparative example was 29 times.
At 120 WHr / cm ² , the number of times was 601 in the example and 722 in the comparative example. As is clear from these comparisons, the effect of the present invention can be confirmed.

[0017]

[Table 1]

[0018]

By using the mixed powder of the indium oxide powder and the metal tin powder according to the present invention, it is possible to form a high-quality ITO film at a high density of 6.7 g / cm ³ or more and sintered. It is possible to obtain a sintered body in which the tin component in the body forms a solid solution in indium oxide and does not exist in the form of tin oxide. Thereby, there is an excellent effect that a nodule generated in the target during film formation by sputtering is suppressed, and an ITO sputtering target that reduces abnormal discharge and particles can be obtained at low cost.

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[Procedure amendment]

[Submission date] May 19, 2000 (2005.1.
9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

[0018]

EFFECT OF THE INVENTION By using the mixed powder comprising the indium oxide powder and the metallic tin powder of the present invention, it is suitable for forming a high quality ITO film, and has a high density of 6.8 g / cm ³ or more and is sintered. It is possible to obtain a sintered body in which the tin component in the body forms a solid solution in indium oxide and does not exist in the form of tin oxide. Thereby, there is an excellent effect that a nodule generated in the target during film formation by sputtering is suppressed, and an ITO sputtering target that reduces abnormal discharge and particles can be obtained at low cost.

Continued on the front page F term (reference) 4G030 AA34 AA61 GA03 GA05 GA11 GA22 GA25 GA27 4K029 BA45 BA50 BC09 CA05 DC05 DC09 5G323 BA01 BA02 BB05 BB06

Claims (16)

[Claims] An indium oxide powder having an average particle size of 1 to 10
A mixed powder of indium oxide and metal tin, comprising a metal tin powder of 0 μm. 2. An average particle diameter of the metal tin powder is 10 to 40 μm.
The indium oxide-metal tin mixed powder according to claim 1, wherein 3. The mixed powder of indium oxide and metal tin according to claim 1, wherein the maximum particle size of the metal tin powder does not exceed 150 μm. 4. The mixed powder of indium oxide and metal tin according to claim 1, wherein the mixed powder of indium oxide and metal tin is finely pulverized and then granulated. 5. An indium oxide powder having an average particle size of 1 to 10
An ITO sputtering target using an indium-metal tin mixed powder as a raw material, characterized in that a mixed powder composed of 0 μm metal tin powder is molded and then sintered, and the sintered body does not contain metal tin. 6. An average particle diameter of the metal tin powder is 10 to 40 μm.
The ITO sputtering target according to claim 5, wherein 7. The ITO sputtering target according to claim 5, wherein the maximum particle size of the metal tin powder does not exceed 150 μm. 8. The ITO sputtering target according to any one of claims 5 to 7, wherein the indium oxide-metal tin mixed powder is finely pulverized and then granulated. 9. The ITO sputtering target according to claim 5, wherein the density of the sintered body is 6.8 g / cm ³ or more. 10. Metal tin powder 0.78 to 11.82 wt.
% Of indium oxide-metal tin mixed powder containing fine particles is granulated and then granulated at normal temperature under a pressure of 700 to 3000 k.
After molding or CIP molding under g / cm ² ,
A method for producing an ITO sputtering target, comprising heating to 1500 to 1650 ° C. and sintering in an oxygen atmosphere or air. 11. The method for producing an ITO sputtering target according to claim 10, wherein the sintered body does not contain metal tin. 12. The IT according to claim 10, wherein the density of the sintered body is 6.8 g / cm ³ or more.
A method for manufacturing an O sputtering target. 13. An indium oxide powder having an average particle size of 1 to 1.
The method for producing an ITO sputtering target according to any one of claims 10 to 12, wherein the ITO sputtering target is an indium-metal tin mixed powder composed of 00 µm metal tin powder. 14. The metal tin powder has an average particle size of 10 to 40 μm.
The method for producing an ITO sputtering target according to any one of claims 10 to 13, wherein m is m. 15. The method for producing an ITO sputtering target according to claim 10, wherein the maximum particle size of the metal tin powder does not exceed 150 μm. 16. The method according to claim 10, wherein the indium oxide-metal tin mixed powder is pulverized and then granulated.
5. The method for producing an ITO sputtering target according to 5 above.