Sintered Oxide Compact Target for Sputtering and Process for Producing the same

• US 20100300878A1
• Filed: 06/05/2009
• Published: 12/02/2010
• Est. Priority Date: 06/10/2008
• Status: Active Grant

• Current Assignee: JX Nippon Mining & Metals Corporation (ENEOS Holdings, Inc.)
• Original Assignee: Nippon Mining & Metals Company Limited (JX Holdings Incorporated)
• Inventors: Osada, Kozo, Ohtsuka, Hiroaki
• Granted Patent: US 9,045,823 B2
• Time in Patent Office: Days
• US Class Current: 204/298.13
• CPC Class Codes: C04B 2235/3284 Zinc oxides, zincates, cadmium oxides, cadmiates, mercury oxides, mercurates or oxide forming salts thereof
• CPC Class Codes: C04B 2235/3286 Gallium oxides, gallates, indium oxides, indates, thallium oxides, thallates or oxide forming salts thereof, e.g. zinc gallate
• CPC Class Codes: C04B 2235/5409 expressed by specific surface values
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/5445 submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/604 Pressing at temperatures other than sintering temperatures
• CPC Class Codes: C04B 2235/656 characterised by specific heating conditions during heat treatment
• CPC Class Codes: C04B 2235/6585 at an oxygen percentage above that of air
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 2235/786 Micrometer sized grains, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/80 Phases present in the sintered or melt-cast ceramic products other than the main phase
• CPC Class Codes: C04B 35/453 based on zinc, tin, or bismuth oxides or solid solutions thereof with other oxides, e.g. zincates, stannates or bismuthates
• CPC Class Codes: C04B 35/6261 Milling
• CPC Class Codes: C04B 35/62655 Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying
• CPC Class Codes: C04B 35/62675 characterised by the treatment temperature
• CPC Class Codes: C04B 35/63416 Polyvinylalcohols [PVA]; Polyvinylacetates
• CPC Class Codes: C23C 14/086 of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• CPC Class Codes: H01B 1/08 oxides

Abstract

Provided is a sintered oxide compact target for sputtering comprising indium (In), gallium (Ga), zinc (Zn), oxygen (O) and unavoidable impurities, wherein the composition ratio of the respective elements satisfies the Formula of In_xGa_yZn_zO_a {wherein 0.2≦x/(x+y)≦0.8, 0.1≦z/(x+y+z)≦0.5, a=(3/2)x+(3/2)y+z}, and the number of ZnGa₂O₄ spinel phases having an average grain size of 3 μm or larger existing in a 90 μm×90 μm area range of the sintered oxide compact target is 10 or less. With this sintered oxide compact target for sputtering comprising In, Ga, Zn, O and unavoidable impurities, the structure of the sintered compact target is improved, the formation of a phase to become the source of nodules is minimized, and the bulk resistance value is reduced. Whereby provided is a high density IGZO target capable of inhibiting abnormal discharge and which can be used in DC sputtering.

Claims

1. A sintered oxide compact target for sputtering comprising indium (In), gallium (Ga), zinc (Zn), oxygen (O) and unavoidable impurities, wherein a composition ratio of the respective elements satisfies a Formula of In_xGa_yZn_zO_a, wherein 0.2≦

x/(x+y)≦

0.8, 0.1≦

z/(x+y+z)≦

0.5, a=(3/2)x+(3/2)y+z, and the number of ZnGa₂O₄ spinel phases having an average grain size of 3 μ

m or larger existing in a 90 μ

m×

90 μ

m area range of the sintered oxide compact target is 10 or less.

2. The sintered oxide compact target for sputtering according to claim 1, wherein a maximum grain size of the ZnGa₂O₄ spinel phases existing in a 90 μ

m×

90 μ

m area range of the sintered oxide compact target is 5 μ

m or less.

3. The sintered oxide compact target for sputtering according to claim 2, wherein a target density is 6.0 g/cm³ or more, and a bulk resistance value is 5.0×

10<sup>−

2</sup> Ω

·

cm or less.

6. The sintered oxide compact target for sputtering according to claim 1, wherein target density is 6.0 g/cm³ or more, and a value of bulk resistance is 5.0×

10<sup>−

2</sup> Ω

·

cm or less.

4. A method of producing a sintered oxide compact target for sputtering comprising indium (In), gallium (Ga), zinc (Zn), oxygen (O) and unavoidable impurities, wherein raw material powders of indium oxide (In₂O₃), gallium oxide (Ga₂O₃), and zinc oxide (ZnO) are adjusted so that a composition ratio of the respective elements will become a Formula of In_xGa_yZn_zO_a, wherein 0.2≦

x/(x+y)≦

0.8, 0.1≦

z/(x+y+z)≦

0.5, a=(3/2)x+(3/2)y+z, a specific surface area of the In₂O₃ raw material powder is set to be 10 m²/g or less, the raw material powders are mixed and additionally pulverized, and thereafter sintered at a temperature range of 1400 to 1480-1490°

C.

5. The method of producing a sintered oxide compact target for sputtering according to claim 4, wherein, during the processing of mixing and pulverizing the raw material powders of In₂O₃, Ga₂O₃ and ZnO, pulverization is performed until the difference in specific surface area before and after pulverization becomes 2.0 m²/g or more.