Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/34—Sputtering
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/34—Sputtering
  • C23C14/3407—Cathode assembly for sputtering apparatus, e.g. Target
  • C23C14/3414—Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy

Definitions

• the present invention relates to an Izo sputtering target suitable for forming a transparent conductive film containing indium and zinc oxide as a main component, which has a fine crystal structure, a high sintered body density, and a high transverse rupture strength, and its production.
• a transparent conductive film containing indium and zinc oxide as a main component which has a fine crystal structure, a high sintered body density, and a high transverse rupture strength, and its production.
• Transparent conductive films made of several metal composite oxides have high conductivity and visible light transmission, so liquid crystal displays, thin film electroluminescent displays, radiation detectors, transparent tablets for terminal equipment, It is used in a wide variety of applications, such as heat generating films for preventing dew condensation on window glass, antistatic films or permselective films for solar collectors, and electrodes for touch panels.
• the most popular of the transparent conductive films made of such a metal composite oxide is a transparent conductive film made of thidium indium indium tin, which is called I ⁇ .
• tin oxide to which antimony ( ⁇ ⁇ ⁇ ) is added or zinc oxide to which aluminum ( ⁇ ⁇ ⁇ ) is added is known. These differ from each other in terms of film characteristics and manufacturing costs, so they are used as appropriate according to the application.
• IZO complex oxide of indium and zinc
• the IZO target used for the film formation at this time was manufactured by a hot isostatic pressing method (see Examples 4 to 12 of the above-mentioned Patent Publication).
• the conventional IZO sputtering target manufactured by this method did not have a sufficiently high sintering density, and had a non-uniform crystal grain size.
• the obtained target did not have sufficiently low Balta resistance, and was not necessarily the optimal sputtering target for DC sputtering.
• an object of the present invention to improve the properties of an IZO transparent conductive film containing indium and zinc oxides as main components without losing the properties, improve the target density, and improve the crystal grain size.
• an IZO sputtering target capable of uniformly miniaturizing and improving mechanical properties, stabilizing sputtering discharge, and obtaining a stable and reproducible transparent conductive film, and a method for producing the same.
• the present invention is based on the following two aspects: 1) an In-rich phase in which Zn is dissolved or insoluble in indium oxide crystals; A sputtering target composed of an indium-zinc-based oxide characterized by having a phase structure.2) The average diameter of the Zn atom aggregates observed by EPMA is 10 ⁇ or less.
• the sputtering target comprising the zinc oxide dumbbell-based oxide as described in 1 above, 3) the average diameter of aggregates of ⁇ atoms observed in ⁇ ⁇ is 5 m or less. 4.
• a sputtering target comprising the indium zinc-based oxide described in 1), 4) a sintered zinc-based oxide according to any one of the above items 1 to 3, wherein the sintered body density is 6.5 g / cm 3 or more.
• Target 5) average crystal
• a sputtering target comprising the zinc oxide based oxide according to any one of the above items 1 to 4, wherein the particle diameter is 3 m or less;
• the sputtering target comprising an indium-zinc oxide according to any of 1 to 5 above, wherein the average crystal grain size is 2 ⁇ m or less.7)
• the surface roughness is 2 m at Ra.
• the sputtering target comprising the zinc oxide according to any one of the above items 1 to 6, characterized in that the average transverse rupture strength is 68 MPa or more.8)
• the surface roughness is 0.
• the sputtering target comprising an indium-zinc-based oxide according to any one of 1 to 6 above, wherein the sputtering target is 5 ⁇ m or less, and the average bending strength is 78 MPa or more.9) Indium-dumbbell-based oxide
• Sputtering target composed of indium zinc oxide, 10) acid After finely pulverizing indium and zinc oxide, they are mixed and granulated, molded by cold pressing and / or isostatic pressing, and then heated to 130 to 150 ° C in an oxygen atmosphere or air.
• Manufacturing method 16) The sputtering target comprising an indium-zinc-based oxide as described in each of 10 to 15 above, wherein the surface roughness is 0 or less in Ra and the average bending strength is 78 MPa or more.
• FIG. 1 is a diagram showing the results of qualitative analysis of indium by EPMA on the surface of an IZO target material of the present invention.
• FIG. 2 is a view showing the results of qualitative analysis of zinc by EPMA on the surface of the IZO target material of the present invention.
• FIG. 3 is a diagram showing the results of qualitative analysis of oxygen by EPMA on the surface of an IZO target material of the present invention.
• FIG. 4 is a diagram showing the cumulative fracture probability with respect to the bending strength of the IZO target of the present invention.
• FIG. 5 is a diagram showing the same Weibull plot of the IZO target of the present invention.
• zinc oxide powder having the same particle diameter as powder of indium oxide having an average particle diameter of 2 ⁇ m is weighed. Weigh the mixture to a ratio of approximately 90:10, add the molding binder, and mix uniformly.
• the mixed powder is filled in a mold, pressed and formed by a cold press and / or a CIP, and then sintered at a temperature of 1300 to 1500 ° C. in the air or an oxygen atmosphere.
• the crystal grain size of the IZO sputtering target sintered body is 3 ⁇ m or less, preferably 2 ⁇ or less, more preferably 1 ⁇ or less. If necessary, increase the density of the sintered body to 6.5 g / cm 3 or more (relative density of 92.9% or more), and further add impurities Fe, Al, Si, Ni, and T in IZ ⁇ . Adjust i and Cu to be less than 10 ppm (wt), respectively.
• the IZO sputtering target thus obtained is composed of an indium oxide crystal in which Zn is solid-dissolved or undissolved, and an In-lithium phase in which zinc is dissolved in zinc oxide crystals. It is a remarkable feature of the present invention that it has a two-phase structure of n-rich phase and that the average aggregate diameter of Zn atoms observed by EPMA is 10 m or less.
• the obtained IZO sputtering target sintered body is ground with a surface grinder to obtain an IZO target material having a surface roughness of Ra 2 im or less, so that the average value of the bending strength is 68 MPa or more. Become. By setting Ra O. 5 m or less, the average value of the flexural strength becomes 78 MPa or more.
• the sputter surface of the IZO sputtering target may be mirror-finished so that the average surface roughness Ra is less than 0.2 ⁇ .
• polishing techniques such as mechanical polishing, chemical polishing, and mechanochemical polishing (combination of mechanical polishing and chemical polishing) can be used.
• polishing with a fixed abrasive polisher polishing liquid: water
• lapping with a loose abrasive wrap abrasive material: SiC paste, etc.
• lapping by changing the abrasive material to diamond paste Obtainable.
• a polishing method There is no particular limitation on such a polishing method, and another polishing method may be employed as long as a good average surface roughness Ra is achieved.
• the obtained IZO sputtering target is bonded to a backing plate.
• a cleaning process such as air blow or running water cleaning is performed. When removing foreign matter by air blow, it is possible to remove the foreign substance more effectively by taking in air from the opposite side of the nozzle with a dust collector.
• ultrasonic cleaning or the like may be further performed. It is effective to carry out this ultrasonic cleaning by performing multiple oscillations at a frequency of 25 to 300 kHz.
• ultrasonic cleaning is preferably performed by multiplexing 12 kinds of frequencies at a frequency of 25 to 30 O KHz at intervals of 25 KHz.
• the bulk resistance value of the IZO sputtering target for forming a transparent conductive film formed in this manner can be set to 1 ⁇ ⁇ cm or less. Thus, the bulk resistance of the IZO sputtering target can be reduced without changing the conventional characteristics of the IZO.
• the target of the present invention is characterized in that it has a high density, has a structure in which the crystal grain size is more uniform and fine, and has a high mechanical strength. As a result, a target film S from which a transparent conductive film can be obtained stably and with good reproducibility can be obtained. Examples and comparative examples
• weighed zinc oxide powder having the same particle size as indium oxide powder having an average particle size of 2 / zm was weighed at a ratio of about 90:10, and after uniform pulverization and mixing, Granulation was performed by adding a molding binder.
• this raw material mixed powder was uniformly filled in a mold and pressed by a cold press machine.
• the molded body thus obtained was sintered at 138 ° C. for 5 hours in a sintering furnace.
• the test was performed in an oxygen atmosphere during heating, in the atmosphere (atmosphere) in the other atmosphere, at a heating rate of 4 ° C / min, and a cooling rate of 10 ° C / min.
• the surface of the sintered body thus obtained was ground with a surface grinder, and the side was cut with a diamond cutter to obtain an Izo target material.
• This IZO target material was 10.7 wt% zinc oxide of zinc oxide, and had a density of 6.87 g / cm 3 (theoretical density of 7.00 g / cm 3 ). Balta resistance was 3.2 mQ cm. Further, the amounts of impurities of Fe, Al, Si, Ti, Ni, and Cu were 10 ppm or less.
• Example 2 a plate with Ra 0.4 ⁇ (Example 1) and a plate with surface grinding in the longitudinal direction to Ra 1.2 // m (Example 2)
• a plate having Ra 2.2 / m by surface grinding in the longitudinal direction was prepared.
• FIGS. Fig. 4 shows the cumulative failure probability with respect to the bending strength by the median rank method
• Fig. 5 shows the Weibull plot by the single mode.
• Table 1 shows the Weibull coefficient (m value) that indicates the variation in the probability of failure from Fig. 5.
• the Weibull coefficient was obtained as the m value by obtaining a linear regression line.
• the larger the Weibull coefficient the less variation in the maximum value of non-destructive stress is seen.From Table 1, it can be seen that the example product has less variation and is a more stable material than the conventional product. Can be confirmed.
• the I ⁇ sputtering target for forming a transparent conductive film of the present invention is substantially in bulk without substantially losing the properties of the ( ⁇ ⁇ ⁇ ⁇ ) transparent conductive film containing indium and zinc oxide as main components. Resistance can be effectively reduced.
• the bulk resistance value of the I ⁇ sputtering target for forming a transparent conductive film thus formed can be controlled within the range of 1 ⁇ ⁇ cm or less.
• the target of the present invention is characterized in that it has a high density, has a structure in which the crystal grain size is more uniform and fine, and has a high transverse rupture strength. This has an excellent feature that a sputtering discharge can be stabilized and a target capable of obtaining a transparent conductive film stably and with good reproducibility can be obtained.

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• Organic Chemistry (AREA)
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Citations (6)

• 1999
  • 1999-11-09 JP JP31823099A patent/JP3628566B2/ja not_active Expired - Lifetime
• 2000
  • 2000-08-02 WO PCT/JP2000/005172 patent/WO2001034869A1/ja active IP Right Grant
  • 2000-08-02 KR KR10-2001-7008548A patent/KR100413958B1/ko active IP Right Grant
  • 2000-12-08 TW TW089126329A patent/TWI225521B/zh not_active IP Right Cessation

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