JP2913054B2 - Manufacturing method of cylindrical ITO target - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ITO target used for forming an indium-tin oxide (hereinafter, referred to as ITO) film by a sputtering method, and particularly to an ITO target. The present invention relates to a method for manufacturing a cylindrical ITO target used for a sputtering apparatus such as ECR (Electron Cyclotron Resonance) and RCM (Rotable Cylindrical Magnetron) which are useful for efficiently obtaining.

The ITO film is a transparent conductive film, for example, a liquid crystal display, an EL (electroluminescence) display,
It is widely used as a permselective membrane, surface heating element, touch panel electrode, and the like.

(Prior art) At present, in order to obtain ITO film by the spaccling method,
Plate-shaped ITO targets are used. As a method of manufacturing these plate-shaped ITO targets, a method of pressing an ITO powder in a mold, firing and obtaining an ITO ingot, and processing the ITO ingot to obtain a target ITO powder There is known a method of hot pressing an ITO ingot and processing it to obtain a target.

By the way, in the magnetron sputtering method using a flat target, the target is sputtered while controlling the plasma by a magnet, so that a magnet-shaped erosion portion is generated on the target surface, and the thickness direction of the portion disappears. At this point, the target life was over, and the target use efficiency was as low as about 20%. Therefore, from the viewpoint of target use efficiency, in recent years, a sputtering apparatus such as an ECR or RCM using a cylindrical target has been developed, and a metal target has already been used to form a film.

However, the ceramic target ITO
In the case of the target, in order to obtain the above-mentioned cylindrical target, it is necessary to form an ingot once by the above-mentioned manufacturing method and then to cut out the inside, which is problematic in terms of processing difficulty.

Furthermore, since the ITO target density affects the deposition rate, film quality, or the discharge stability during sputtering, a high-density ITO target is strongly desired.
The ITO target obtained by the above method has a problem that the density is low.

(Problem to be Solved by the Invention) An object of the present invention is to provide a method for easily manufacturing a high-density cylindrical ITO target.

(Means for Solving the Problems) As a result of intensive studies to solve the above problems, the present inventors have found that ITO powder is molded by a cold isostatic press (hereinafter referred to as CIP) and fired. As a result, it has been found that a high-density cylindrical ITO target can be easily obtained with a high yield, and the present invention has been completed. That is, the present invention is a method for producing a cylindrical ITO target, which includes a step of obtaining a cylindrical ITO powder molded body by CIP and a step of firing the obtained molded body.
Hereinafter, the present invention will be described in detail.

The method of manufacturing a cylindrical ITO target in the present invention includes a step of obtaining a cylindrical ITO powder molded body by CIP.This step is, for example, filling a cylindrical CIP mold with ITO powder and directly CIPing the ITO powder. It can be carried out by a method or a method in which ITO powder is preliminarily formed into a cylindrical shape and the obtained preformed body is CIPed. Further, the pressure in this CIP is preferably set at 500 kg / cm ² or more, and the density of the cylindrical ITO target obtained by increasing the CIP pressure is improved.

When directly CIPing ITO powder, the particle size of the ITO powder used should be 1000 μm to facilitate the processability of the obtained ITO powder.
m or less, and the particle size is more preferably 300 to 750 μm.
It is preferable to adjust to m. Further, the CIP type used for direct CIP is not particularly limited as long as it is a cylindrical shape. For example, a type as shown in FIG. 1 can be used. The CIP type shown in FIG. 1 is composed of upper and lower lid portions 1, a cylindrical portion 2, and a core 3, which are joined at predetermined positions, and the core 3 is joined to the upper and lower lid portions 1. A portion between the cylindrical portion 2 and the core 3 is filled with ITO powder, and CIP is performed. In addition, when directly CIPing ITO powder, cracks may occur in the obtained ITO powder molded body when CIP is performed under high pressure from the beginning.
By performing P in two or more stages, the occurrence of cracks can be suppressed. At this time, the CIP in the first stage is 5
Primary 00~2000kg / cm ² approximately cylindrical performed under low pressure
It is preferable to obtain a CIP molded body and then CIP the primary molded body obtained in the second or higher stage at a higher pressure.

On the other hand, when CIPing a preformed body obtained in advance, the preform is a cylindrical ITO that can be used for CIP.
Any method can be used as long as a powder molded body can be obtained, and examples thereof include a die press molding method and a cast molding method. However, in consideration of the simplicity of operation and the raw material yield, the cast molding method is used. Is preferred. The casting method is performed by injecting a slurry containing ITO powder into a casting mold. The casting mold used at this time is not particularly limited as long as it has a cylindrical shape, and its material is not particularly limited as long as it absorbs the solvent of the slurry, such as gypsum or resin. Is used. The slurry containing the ITO powder can be obtained, for example, by adding water, a binder, and a dispersant to the ITO powder. At this time, it is preferable that the amount of the binder and the dispersant contained in the slurry is small. Further, the slurry concentration is preferably 70% or more, and if it is less than 70%, cracks may occur during the production of the target. Furthermore, in the casting method, the slurry is reduced to 0.
By performing pressure casting in which injection is performed into a mold with a pressure of 5 kg / cm ² or more, a preform of high density ITO powder can be obtained in a short time.

A cylindrical ITO molded body can be obtained by the above method.
The target is obtained. The firing temperature at this time is 1300-14
It is preferable to carry out at 50 ° C. for 1 hour or more.

The cylindrical ITO target obtained by the above method has a relative density as high as 75% or more because the ITO powder compact before firing is compacted by CIP. A cylindrical ITO target with good productivity and target characteristics.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited to these.

Example 1 4750 g of commercially available In ₂ O ₃ powder and 250 g of SnO ₂ powder were dry-mixed in a 10-liter nylon pot using a 15 mm-diameter resin core-containing resin pole by a rotary ball mill for 16 hours to obtain a raw material powder. Next, the particle size of the obtained raw material powder was adjusted using a 710 μm sieve, and the raw material powder having been subjected to the particle size adjustment was filled in a CIP mold shown in FIG. The CIP type used was made of rubber, and its cylindrical part had an outer diameter of 130 mm and an inner diameter of 90 m.
m and height 70 mm.

Thereafter, the ITO powder was filled in CIP type at a pressure of 1500 kg / cm ²
CIP to obtain a primary CIP molded, further resulting extract only primary CIP molded, which vacuum-sealed in 1mm thick rubber bag, and CIP again a pressure of 5000 kg / cm ^2, the cylindrical An ITO powder compact was obtained.

Thereafter, the obtained molded body was fired at 1400 ° C. for 5 hours to obtain a sintered body, which was processed, and had an outer diameter of 110 mm, an inner diameter of 90 mm, and a height of 5 mm.
A 0 mm cylindrical ITO target was obtained.

The relative density of the obtained cylindrical ITO target was 82%, and the raw material yield was 65% based on the raw material powder used.

Example 2 2375 g of commercially available In ₂ O ₃ powder, 125 g of SnO ₂ powder, 112.5 g of an acrylic emulsion binder (40% solids), 56.25 g of a polycarboxylic acid dispersant (40% solids), and 554.7 g of pure water
In a 5 l nylon pot, use a resin ball containing an iron core with a diameter of 15 mm, mix with a rotating ball mill for 16 hours, and mix
An 80% slurry was obtained.

Next, after sufficiently defoaming the obtained slurry, it was poured into a cylindrical gypsum casting mold, and after injection, press-molded at 2 kg / cm ² to obtain a cylindrical ITO powder preform. The size of the cylindrical portion of the casting mold has an outer diameter of 13
0 mm, inner diameter 95 mm, height 80 mm.

Then drying the resulting ITO powder preform, which was vacuum-sealed up in 1mm thick rubber bag, obtain an ITO powder molded body of a cylindrical shape performs CIP under a pressure 5000 kg / cm ^2, it After debinding, firing at 1400 ° C for 5 hours to obtain a sintered body,
Further, the obtained sintered body is 110 mm in outer diameter, 90 mm in inner diameter, and 50 m in height.
m to obtain a cylindrical ITO target.

The relative density of the obtained cylindrical ITO target was 79%, and the raw material yield was 63% based on the raw material powder used.

Comparative Example 9500 g of commercially available In ₂ O ₃ powder, 500 g of SnO ₂ powder and 30 g of binder (paraffin) were weighed in a 10-liter nylon pot.
Using a 15 mm iron core-containing resin ball, dry-mixing is performed for 16 hours by a rotary ball mill.
Pressing at ² cm ² yielded an ITO powder compact. Thereafter, the obtained molded body was debindered and fired at 1350 ° C. for 5 hours to obtain an ingot having a diameter of 115 mm and a height of 80 mm, and a cylindrical target having an outer diameter of 110 mm, an inner diameter of 90 mm, and a height of 50 mm was formed by hollowing. Obtained.

In the above method, the relative density of the obtained target was as low as 64%, and the raw material yield was 19% based on the raw material powder used.
Met.

(Effect of the Invention) As described above, according to the present invention, a high-density cylindrical ITO target can be obtained. Furthermore, according to the present invention, it is possible to easily obtain a cylindrical ITO target with good yield.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a CIP type used in the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C23C 14/00-14/58 C04B 35/00-35/22

Claims (2)

(57) [Claims] The present invention relates to a method for producing a cylindrical primary molded body by cold pressing an ITO powder at a pressure of 500 to 2,000 kg / cm ² to produce a cylindrical primary molded body. A step of obtaining a cylindrical ITO powder molded body by a two-stage cold isostatic press at a higher pressure than a cold isostatic press, and a step of firing the obtained molded body. Manufacturing method of ITO target. 2. A slurry concentration of 70% or more and a molding pressure of 0.5 kg / cm.
Including a step of obtaining a cylindrical ITO powder molded body by cold isostatic pressing of a cylindrical primary molded body obtained by a casting method under ^two or more conditions and a step of firing the obtained molded body A method for producing a cylindrical ITO target, characterized in that: