JP2017179464A - Cylindrical sputtering target and packaging method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sputtering target capable of suppressing arcing from occurring during sputtering.SOLUTION: A cylindrical sputtering target includes a cylindrical sintered body, a cylindrical base material bonded to the inner side of the sintered body with bonding material interposed therebetween, and a protective member covering both ends of the base material to seal a gas-filled hollow part of the base material. Further, a packaging method of the cylindrical sputtering target includes: filling gas in the hollow part of the cylindrical base material; and forming a protective member so as to cover opening parts on both ends of the base material and seal the hollow part.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cylindrical sputtering target and a packaging method thereof.

  In recent years, flat panel display (FPD) manufacturing technology and solar cell manufacturing technology have been rapidly developed, and the market for large-sized flat-screen televisions and solar cells has increased. In addition, with the development of these markets, the size of glass substrates is increasing in order to reduce the manufacturing costs of products. Currently, development of an apparatus for a size of 2200 mm × 2400 mm, which is said to be the eighth generation, is in progress.

  In particular, in a sputtering apparatus for forming a metal thin film or a metal oxide thin film on a large glass substrate, a flat plate type sputtering target or a cylindrical type (also referred to as a rotary type or a rotary type) sputtering target is used. Cylindrical sputtering targets have advantages in that the use efficiency of the target is high, erosion is less generated, and particles are not generated due to peeling of deposits, compared to flat plate sputtering targets.

  When a thin film is formed by a sputtering method, generation of particles causes a pattern defect or the like. The most common cause of the generation of particles is abnormal discharge (arcing) that occurs during sputtering. In particular, when arcing occurs on the target surface, the surrounding target material where arcing has occurred is released from the target in a cluster shape (block shape) and adheres to the substrate. Causes of arcing include debris adhering to the target surface and alteration of the target surface due to moisture adhering to the target surface.

  The sputtering target is desirably stored in an air-conditioned area, but is usually stored in a general warehouse that is not air-conditioned. Therefore, in order to protect the target from dust and moisture, the target is stored in a state of being wrapped by a protective film or the like after the target is manufactured until it is used. For example, Patent Document 1 suppresses dust and moisture from adhering to the target by storing the flat-plate-type sputtering target in a vacuum-packed state with a protective member.

Japanese Patent No. 5032662

  However, the cylindrical sputtering target has a so-called hollow structure in which the inside of the cylinder is hollow. Therefore, when the cylindrical sputtering target is vacuum-packed with the protective member as described above, the protective member is pressed inside the cylinder by the atmospheric pressure. In this state, if the surface of the protective member is damaged, the protective member is broken by using the scratch. When the protective member is broken, dust and moisture from the external environment enter the protective member and adhere to the surface of the cylindrical sputtering target. When sputtering is performed using a cylindrical sputtering target in which dust is attached to the surface of the target or in which the surface of the target is altered due to the attachment of moisture, there is a problem that arcing occurs frequently.

  In view of the above circumstances, an object of the present invention is to provide a sputtering target capable of suppressing the occurrence of arcing during sputtering.

  A cylindrical sputtering target according to an embodiment of the present invention includes a cylindrical sintered body, a cylindrical base material joined to the inside of the sintered body via a joining material, and openings at both ends of the base material. And a protective member that seals and seals the hollow portion of the base material filled with gas.

  The gas may be argon or nitrogen.

  Further, the pressure of the gas in the space may be 30 kPa or more and 60 kPa or less.

  The dew point temperature of the gas in the space may be -80 ° C or higher and -50 ° C or lower.

  The sintered body may contain ITO, IZO, or IZGO as a main component.

  A method of packing a cylindrical sputtering target according to an embodiment of the present invention includes a cylindrical sputtering body having a cylindrical sintered body and a cylindrical base material joined to the inside of the sintered body via a joining material. In this method of packing a target, a protective member is formed so as to fill a hollow portion of a base material with gas, cover openings at both ends of the base material, and seal the hollow portion.

  Further, before filling the gas, the gas in the hollow part may be exhausted, the inert gas may be introduced into the exhausted hollow part, and the inert gas may be exhausted.

  ADVANTAGE OF THE INVENTION According to this invention, the sputtering target which can suppress the arcing generation | occurrence | production during sputtering can be provided.

It is a perspective view which shows the cylindrical sputtering target which concerns on one Embodiment of this invention. It is sectional drawing which shows the cylindrical sputtering target which concerns on one Embodiment of this invention. It is a process flow which shows the manufacturing method of the sputtering target which concerns on one Embodiment of this invention. It is a process flow which shows the method filled with gas in the manufacturing method of the sputtering target which concerns on one Embodiment of this invention. It is sectional drawing which shows the cylindrical sputtering target which concerns on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be implemented in various modes without departing from the gist thereof, and is not construed as being limited to the description of the embodiments exemplified below.

  Further, in order to make the explanation clearer, the drawings may be schematically represented with respect to the width, thickness, shape, and the like of each part as compared with the actual embodiment, but are merely examples, and the interpretation of the present invention. It is not intended to limit. In addition, in the present specification and each drawing, elements having the same functions as those described with reference to the previous drawings may be denoted by the same reference numerals and redundant description may be omitted.

In the following description, the density of the molded body and the density of the sintered body are shown as relative densities. The relative density is expressed by the relative density = (measured density / theoretical density) × 100 (%) according to the theoretical density and the measured density. The theoretical density is a density value calculated from the raw material used. When the raw material is weighed so that indium oxide is 90% by mass and tin oxide is 10% by mass, the density of (In ₂ O ₃ (g / Cm ³ ) × 90 + SnO ₂ density (g / cm ³ ) × 10) / 100. The density of In ₂ O ₃ is calculated as 7.18 g / cm ³ , the density of SnO ₂ is calculated as 6.95 g / cm ³ , and the theoretical density is calculated as 7.15 (g / cm ³ ). On the other hand, the measured density is a value obtained by dividing weight by volume. In the case of a molded body, the volume is calculated using the volume calculated by actually measuring the dimensions. In the case of a sintered body, the volume is calculated by the Archimedes method.

<Embodiment 1>
[Configuration of Cylindrical Sputtering Target 100]
FIG. 1 is a perspective view showing a cylindrical sputtering target according to an embodiment of the present invention. Moreover, FIG. 2 is sectional drawing which shows the cylindrical sputtering target which concerns on one Embodiment of this invention.

  The cylindrical sputtering target 100 according to the present embodiment includes a cylindrical substrate 110 and a cylindrical sintered body 120. The base material 110 is bonded to the inner surface of the sintered body 120 via the bonding material 130. The bonding material 130 is provided so as to fill a gap provided between the base material 110 and the sintered body 120. The sintered body 120 and the base material 110 have a so-called hollow structure in which a space is provided inside the cylinder.

  As shown in FIG. 2, the substrate 110 and the sintered body 120 are covered with a protective member 140. The protective member 140 covers the circumferential surface 122 and the side surface 124 of the sintered body 120, and the circumferential surface 112, the side surface 114, and the opening 116 exposed from the sintered body 120 of the substrate 110. By covering the openings 116 at both ends of the base 110 with the protection member 140, the space 150 on the inner surface side of the base 110 is sealed. This sealed space 150 is filled with gas.

  In other words, the cylindrical sputtering target 100 includes a cylindrical sintered body 120, a cylindrical substrate 110 bonded to the inner surface of the sintered body 120 via a bonding material 130, and a substrate. A protective member 140 that covers the openings 116 at both ends of 110 and seals the space 150 on the inner surface side of the base material 110 filled with gas.

Here, the gas filled in the space 150 will be described in detail. As the gas filled in the space 150, for example, argon (Ar) or nitrogen (N ₂ ) can be used. The pressure of the gas filled in the space 150 is preferably 30 kPa or more and 60 kPa or less. More preferably, it is 40 kPa or more and 50 kPa or less.

  When the gas pressure is lower than the lower limit, the difference between the pressure in the space 150 and the external atmospheric pressure increases. Therefore, the protective member 140 disposed in the opening 116 is pressed toward the inside of the space 150, and the protective member 140 receives strong pressure particularly at the end portion on the inner surface side of the side surface 114 of the base material 110. Therefore, if the protective member 140 near the end portion on the inner surface side of the side surface 114 is slightly damaged, the protective member 140 may be broken by using the scratch as a trigger. On the other hand, when the gas pressure is higher than the upper limit value, the protective member 140 may expand and may burst with a slight scratch. In particular, the sputtering target may be transported by air. Therefore, if the gas pressure is higher than the upper limit value, the protective member 140 may be broken due to the volume expansion of the gas during transportation.

  The space 150 preferably has a small amount of moisture. That is, the dew point temperature of the gas filled in the space 150 is preferably −50 ° C. or lower. More preferably, it is good at -80 degrees C or less. If the dew point temperature is higher than the upper limit value, the inside of the protective member 140 may condense depending on the storage environment. When the inside of the protective member 140 is condensed, a deteriorated layer is formed on the surface of the sintered body 120 due to the condensed moisture. This altered layer can cause arcing when the sputtering target is used.

[Substrate 110]
The substrate 110 preferably has an outer surface shape that follows the inner surface of the cylinder of the sintered body 120. The outer diameter of the base material 110 is slightly smaller than the inner diameter of the sintered body 120, and when the base material 110 and the sintered body 120 are coaxially stacked, there is a gap between the base material 110 and the sintered body 120. Adjusted to be able to. A bonding material 130 is provided in the gap.

  The base material 110 is preferably a metal that has good wettability with the bonding material 130 and can provide high bonding strength with the bonding material 130. For example, it is preferable to use copper (Cu) or titanium (Ti), a copper alloy, a titanium alloy, or stainless steel (SUS) as a material constituting the substrate 110. As the copper alloy, an alloy mainly composed of copper (Cu) such as chromium copper can be applied. In addition, if titanium (Ti) is used as the base material 110, a lightweight and rigid base material can be obtained.

[Sintered body 120]
As shown in FIGS. 1 and 2, the sintered body 120 is provided so as to surround the circumferential surface of the substrate 110. The sintered body 120 is preferably provided coaxially or substantially coaxially with the central axis of the substrate 110. With such a configuration, when the cylindrical sputtering target 100 is mounted on the sputtering apparatus and rotated around the base material 110, the distance between the surface of the sintered body 120 and the film formation surface (sample substrate) is constant. Can be kept in.

  The sintered body 120 is formed into a hollow cylindrical shape. The relative density of the sintered body 120 is preferably 99.0% or more and 99.9% or less. Preferably, the relative density of the sintered body 120 is 99.7% or more and 99.9% or less. In addition, the relative density of the target member or molded object which concerns on embodiment of this invention is the value evaluated by the Archimedes method. Moreover, the thickness of the sintered compact 120 can be 6.0 mm or more and 15.0 mm or less. The thickness part of the sintered compact 120 can be utilized as a target member. The length of the sintered body 120 in the cylindrical axis direction can be set to 150 mm or more and 380 mm or less. Here, in the state before performing sputtering (before being exposed to the plasma atmosphere or before using the sputtering target), the surface roughness of the sintered body 120 is such that the average surface roughness (Ra) is less than 0.5 μm. Good.

  Furthermore, the sintered body 120 is formed using various materials that can be formed by sputtering. For example, the sintered body 120 may be a ceramic. As the ceramic, a metal oxide, a metal nitride, a sintered body of metal oxynitride, or the like can be used. As the metal oxide, an oxide of a metal belonging to a typical element such as indium oxide, tin oxide, zinc oxide, or gallium oxide can be used.

  Specifically, a compound of tin oxide and indium oxide (Indium Tin Oxide: ITO), zinc oxide (Zinc Oxide: ZnO), a compound of indium oxide and zinc oxide (Indium Zinc Oxide: IZO), indium oxide, zinc oxide, and A compound selected from a compound of gallium oxide (Indium Gallium Zinc Oxide: IGZO) or the like can be used as the sintered body 120.

[Bonding material 130]
The bonding material 130 is provided between the base material 110 and the sintered body 120. The bonding material 130 preferably bonds the base material 110 and the sintered body 120 and has good heat resistance and thermal conductivity. Further, since it is placed under vacuum during sputtering, it is preferable to have a characteristic that gas emission is low in vacuum.

  Further, from the viewpoint of manufacturing, the bonding material 130 preferably has fluidity when the base material 110 and the sintered body 120 are bonded. In order to satisfy these characteristics, a low melting point metal material having a melting point of 300 ° C. or lower can be used as the bonding material 130. For example, as the bonding material 130, a metal such as indium (In) or tin (Sn), or a metal alloy material containing any one of these elements may be used. Specifically, indium or tin alone, an alloy of indium and tin, a solder alloy containing tin as a main component, or the like may be used.

[Protective member 140]
The protective member 140 is made of a film-like resin. As a material for the protective member 140, a laminated film obtained by laminating a plurality of films having different properties can be used. For example, a laminated film in which a functional film is sandwiched between two polyethylene films can be used. As the polyethylene film, a material having a lower melting temperature by heat than the functional film can be used. With the configuration in which the polyethylene film sandwiches the functional film, the polyethylene films are surely melted at the time of heat sealing, so that the protective member 140 can be reliably sealed. The functional film preferably has at least one of oxygen permeability and moisture permeability lower than that of the polyethylene film. Moreover, it is preferable that a functional film has at least any one of piercing strength and tensile strength higher than a polyethylene film.

  Specifically, Idemitsu Unitech Unilon (registered trademark) can be used as the functional film of the protective member 140, preferably Asahi Kasei Saran Wrap (registered trademark), more preferably Kuraray Eval (registered trademark). (Trademark) film can be used. Here, the physical properties of Unilon, Saran Wrap, and Eval film are as follows.

[Unilon]
・ Oxygen permeability (20 ° C. 90% RH): 37 cc / d · atm
Moisture permeability (40 ° C 90% RH): 90 g / m ² · day
・ Puncture strength: 16.0 kgf (10.9 × 10 ⁻³ MPa)
・ Tensile strength: 260 MPa

[Saran Wrap]
・ Oxygen permeability (20 ° C. 90% RH): 60 cc / d · atm
Moisture permeability (40 ° C 90% RH): 12 g / m ² · day
・ Tensile strength: 470 MPa

[Eval film]
・ Oxygen permeability (20 ° C. 90% RH): 30 cc / d · atm
Moisture permeability (40 ° C 90% RH): 5.3 g / m ² · day
・ Puncture strength: 11.1 kgf (10.9 × 10 ⁻³ MPa)
・ Tensile strength: 40 MPa

  In addition, a functional film is not limited to said film, A various film can be used according to the objective.

  In addition, said specific example is an example and the sputtering target which concerns on this embodiment can use various sputtering materials as a target member.

  When the sintered body 120 is attached to the base material 110, the base material 110 is inserted into the hollow portion of the sintered body 120, and then both are joined by the joining material 130. That is, the outer diameter of the base material 110 is smaller than the inner diameter of the sintered body 120 (the diameter of the hollow portion), and the base material 110 and the sintered body 120 are arranged at a predetermined interval and fill this gap. Thus, the bonding material 130 is provided. In order to stably hold the sintered body 120 and the base material 110, the bonding material 130 is provided with no gap in the gap.

[Method of manufacturing sputtering target]
Next, a method for manufacturing the cylindrical sputtering target 100 according to this embodiment will be described in detail. FIG. 3 is a process flow showing a method for manufacturing a sputtering target according to an embodiment of the present invention.

  In this embodiment, an example in which an indium tin oxide (ITO) sintered body is used as a sintered body 120 is shown. However, the material of the sintered body 120 is not limited to ITO, and IZO, IGZO, or other metal oxide compounds are used. You can also.

  First, raw materials constituting the sintered body 120 are prepared. In this embodiment, indium oxide powder and tin oxide powder are prepared (S301, S302). The purity of these raw materials is usually 2N (99% by mass) or more, preferably 3N (99.9% by mass) or more, more preferably 4N (99.99% by mass) or more. If the purity is lower than 2N, the sintered body 120 contains a large amount of impurities, so that desired physical properties cannot be obtained (for example, decrease in transmittance of the formed thin film, increase in resistance value, generation of particles due to arcing). ) May arise.

  Next, these raw material powders are pulverized and mixed (S303). The raw material powder is pulverized and mixed using a dry method using balls and beads (so-called media) of zirconia, alumina, nylon resin, etc., media agitating mills using the balls and beads, and medialess containers Wet methods such as a rotary mill, a mechanical stirring mill, and an airflow mill can be used. Here, since the wet method is generally superior in pulverization and mixing ability compared to the dry method, it is preferable to perform the mixing using the wet method.

  Although there is no restriction | limiting in particular about the composition of a raw material, It is desirable to adjust suitably according to the composition ratio of the target sintered compact 120. FIG.

  Next, the raw material powder slurry is dried and granulated (S303). At this time, the slurry may be rapidly dried using rapid drying granulation. The rapid drying granulation may be performed by using a spray dryer and adjusting the temperature and air volume of hot air.

  Next, the mixture obtained by mixing and granulating as described above (preliminarily fired when provisional firing is provided) is pressure-molded to form a cylindrical shaped body (S304). By this step, the target sintered body 120 is formed into a suitable shape. Examples of the molding process include mold molding, cast molding, injection molding, and the like. In order to obtain a complicated shape such as a cylindrical mold, cold isostatic pressing (CIP) is used. It is preferable to form by, for example. The molding pressure by CIP is preferably 100 MPa or more and 200 MPa or less. By adjusting the molding pressure as described above, a molded body having a relative density of 54.5% or more and 58.0% or less can be formed. By setting the relative density of the molded body within the above range, the relative density of the sintered body 120 obtained by subsequent sintering can be set to 99.7% or more and 99.9% or less.

Next, the cylindrical molded body obtained in the molding process is sintered (S305). An electric furnace is used for sintering. The sintering conditions can be appropriately selected depending on the composition of the sintered body. For example, SnO ₂ is 10 wt. If it is contained, it can be sintered by placing it in an oxygen gas atmosphere at a temperature of 1400 ° C. to 1600 ° C. for 10 hours to 30 hours. When the sintering temperature is lower than the lower limit, the relative density of the sintered body 120 is lowered. On the other hand, when the temperature exceeds 1600 ° C., the electric furnace and the furnace material are greatly damaged and frequent maintenance is required, so that the work efficiency is remarkably lowered. Moreover, when the sintering time is shorter than the lower limit, the relative density of the sintered body 120 is lowered. Further, the pressure during sintering may be atmospheric pressure or a pressurized atmosphere.

  Next, the formed cylindrical sintered body is machined into a desired cylindrical shape using a machining machine such as a surface grinder, a cylindrical grinder, a lathe, a cutting machine, or a machining center (S306). . The machining performed here is a process of processing a cylindrical sintered body to have a desired shape and surface roughness, and finally, the sintered body 120 is formed through this process.

Next, the machined sintered body 120 is subjected to ultrasonic cleaning treatment in pure water, thereby removing the machining grinding dust adhering to the surface of the sintered body 120. continue,
The sintered body 120 is bonded (bonded) to the base material 110 via the bonding material 130 (S307). For example, when indium is used as the bonding material 130, molten indium is injected into the gap between the sintered body 120 and the substrate 110. In this way, the cylindrical sputtering target 100 can be obtained.

  Next, the cylindrical sputtering target 100 is packed using the protective member 140. The protective member 140 is formed so as to cover at least the circumferential surface 122 and the side surface 124 of the sintered body 120 and the opening 116 of the substrate 110. By covering the opening 116 with the protective member 140, the space 150 is sealed. Here, before the space 150 is sealed with the protective member 140, the space 150 of the base 110 is filled with the above gas. A method of filling the space 150 with gas will be described later.

  Then, the cylindrical sputtering target 100 packed with the protective member 140 as described above is stored (S308).

[Method for filling gas into space 150]
Here, a method of filling the space 150 with gas will be described in detail. FIG. 4 is a process flow showing a gas filling method in the sputtering target manufacturing method according to one embodiment of the present invention.

  First, in order to replace the gas existing in the space 150 with a desired gas, the gas in the space 150 is exhausted, and an inert gas is introduced into the exhausted space 150. Then, after exhausting the inert gas introduced into the space 150, the gas 150 is filled with the gas (S401, S402). The process of “exhaust, introduction of inert gas, exhaust” is called cycle exhaust because the exhaust is repeated a plurality of times. Note that the exhaust of the gas in the space 150 and the introduction of the inert gas may be repeated a plurality of times. By doing in this way, the purity of the gas filled in the space 150 can be brought close to the purity of the supplied gas. As a result, the space 150 can be filled with high-quality gas with little dust and moisture. Then, the cylindrical sputtering target 100 is packed by the protective member 140 in a state filled with gas (S403).

  In the cycle exhaust, exhaust or gas is introduced from the other opening 116 in a state where one opening 116 of the cylindrical sputtering target 100 is covered with the protective member 140. Specifically, the one opening 116 is covered with the bottom of the bag-shaped protection member 140. The protection member 140 is sandwiched by a heat sealer in a state where piping is inserted toward the inside of the protection member 140 on the opening end side (the other opening 116 side) of the protection member 140. The exhaust or gas introduction is performed through the pipe. For example, a desired gas is introduced into the space 150 after exhaust and gas introduction are repeated three times. After the piping is removed from the heat sealer, the open end of the protective member 140 is closed by the heat sealer. In this way, the space 150 is sealed by the protective member 140.

  As described above, according to the sputtering target manufacturing method of the present embodiment, the space 150 of the substrate 110 is filled with the gas, so that the protective member 140 disposed in the opening 116 enters the space 150 inside. Since the pressing is suppressed, the protection member 140 can be prevented from being broken. Therefore, it is possible to suppress dust and moisture from adhering to the cylindrical sputtering target 100 during storage. As a result, it is possible to provide a sputtering target that can suppress the occurrence of arcing during sputtering.

<Embodiment 2>
A cylindrical sputtering target according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view showing a cylindrical sputtering target according to an embodiment of the present invention. The cylindrical sputtering target 200 according to the second embodiment is different from the cylindrical sputtering target 100 according to the first embodiment in that a plurality of cylindrical sintered bodies 120 a and 120 b are bonded to a cylindrical base material 110. . In the following description, description is abbreviate | omitted about the structure similar to the cylindrical sputtering target 100 of Embodiment 1, and a difference is demonstrated.

  As shown in FIG. 5, the protective member 140 is exposed from the circumferential surface 122a and the side surface 124a of the sintered body 120a, the circumferential surface 122b and the side surface 124b of the sintered body 120b, and the sintered body 120 of the substrate 110. The circumferential surface 112, the side surface 114, and the opening 116 are covered. Here, a space 160 is provided in a region between the sintered body 120a and the sintered body 120b. The space 160 is a region surrounded by the circumferential surface 112c, the protective member 140, the side surface 124a, and the side surface 124b of the substrate 110 exposed from these sintered bodies. The space 160 is filled with the same gas as the space 150.

[Example 1]
In the process of forming a protective member in the process flow shown in FIG. 3 (S308), the inventors packed and stored the cylindrical sputtering target by four different methods, and investigated whether the protective member 140 was easily broken. The target samples used for the survey are as follows.

[Target shape (common to all target samples)]
-Length of base material 110 in the cylindrical axis direction: 2525 mm
・ Cylinder outer diameter of substrate 110: 153 mm
・ Cylinder inner diameter of substrate 110: 135 mm
-Length of sintered body 120 in the cylindrical axis direction: 2619 mm
・ Cylinder outer diameter of sintered body 120: 133 mm
-Cylindrical inner diameter of sintered body 120: 125 mm

[Packing conditions for protective member 140]
- Example 1: Packaging and examples in the protective member 140 is filled with Ar to the space 150 2: Packaging and Comparative Examples protective member 140 filled with _{N 2} in the space 150 1: vacuum space 150 (1 Pa or less) Packing with protective member 140 / Comparative Example 2: Filling space 150 with air whose humidity has not been adjusted and packing with protective member 140 Note that before the gas filling in Example 1 and Example 2, the above exhaust And introduction of inert gas was repeated three times. The dew point temperature of the above Ar and N ₂ was about −50 ° C., and the dew point temperature of the atmosphere was about 10 ° C. Further, Ar, N ₂ and the atmospheric pressure filling the space 150 are 50 kPa.

[Investigation result]
The target sample packed under the above conditions was examined for the presence or absence of breakage of the protective member 140. The number of samples in which the protective member 140 is broken for each sample is as follows.
-Example 1: Number of samples where the protective member 140 was broken = 1/100-Example 2: Number of samples where the protective member 140 was broken = 2/100-Comparative Example 1: Number of samples where the protective member 140 was broken = 45/100 pieces / Comparative Example 2: Number of samples in which the protective member 140 was broken = 3/100 pieces

  As described above, it has been found that the protective member 140 is difficult to break in the sample in which the space 150 is filled with a gas having a pressure of at least 50 kPa and packed with the protective member 140.

[Example 2]
Next, the result of investigating the correlation between each packing method and the initial cumulative arcing occurrence number will be described. The sample used in Example 2 is the same as the sample in Example 1. The initial cumulative arcing occurrence number is the cumulative number of arcing occurrences that occurred during pre-sputtering until the sputtering apparatus reaches the operating state in the production line by evacuating the sputtering target attached to the sputtering apparatus. is there.

  Here, the arcing generated during the above pre-sputtering will be described in detail. In order to mount the sputtering target on a sputtering apparatus, it is necessary to open a vacuum chamber for performing sputtering to the atmosphere. When the vacuum chamber is opened to the atmosphere, moisture, gas and organic substances in the atmosphere adhere to the inner wall of the vacuum chamber. Similarly, moisture, gas, and organic substances in the atmosphere adhere to the surface of the sputtering target. As described above, when pre-sputtering is performed with moisture, gas, and organic substances adhering to the surface of the vacuum chamber and the sputtering target, electrons emitted from the plasma are charged to the adhering substances, and the charge amount is limited. Reaching causes arcing. Therefore, more arcing occurs during pre-sputtering than in the operating state.

  The arcing during the pre-sputtering gradually decreases as the pre-sputtering is continued, and the arcing frequency is stabilized within a certain range. Then, the pre-sputtering is finished when the occurrence frequency of arcing is stabilized. That is, the initial cumulative arcing occurrence number is the cumulative number of arcing occurrences that occurred during pre-sputtering.

  In this embodiment, a correlation between a packing method of a cylindrical sputtering target by a protective member, the number of initial accumulated arcing occurrences, and the number of particle occurrences in a thin film after film formation will be described.

The sputtering conditions for evaluating the initial cumulative arcing occurrence frequency will be described. The target and the sputtering conditions for which the initial cumulative arcing occurrence frequency was evaluated in this example are as follows.
(Evaluation target)
Target material: ITO (SnO ₂ = 10%)
(Sputtering conditions)
Sputtering gas: Ar
Sputtering pressure: 0.6 Pa
Sputtering gas flow rate: 300 sccm
Sputtering power: 4.0 W / cm ²

[Investigation result]
The number of initial cumulative arcing occurrences using the target sample packed and stored under the conditions described in Example 1 is as follows. The number of arcing occurrences is the cumulative number of arcing occurrences until the integrated power amount reaches 30 Whr / cm ² . In addition, the comparative example 1 is a result using the sample by which the tear was confirmed by the protective member 140 after storage.
-Example 1: 226-Example 2: 285-Comparative Example 1: 1,049-Comparative Example 2: 1,124 In Comparative Example 2, arcing marks of about 3 mm are scattered on the target surface. Was. This is presumably due to arcing caused by fine water droplets adhering during storage.

  As described above, it has been found that arcing due to water droplets can be suppressed by using a gas having a dew point temperature of −50 ° C. as the gas filling the space 150.

  The embodiments described above as the embodiments of the present invention can be implemented in appropriate combination as long as they do not contradict each other. Also, those in which those skilled in the art appropriately added, deleted, or changed the design based on the display device of each embodiment, or those in which the process was added, omitted, or changed in conditions are also included in the present invention. As long as the gist is provided, it is within the scope of the present invention.

  In addition, even for other operational effects different from the operational effects brought about by the aspects of the above-described embodiments, those that are apparent from the description of the present specification, or that can be easily predicted by those skilled in the art, Of course, it is understood that the present invention provides.

100, 200: Cylindrical sputtering target 110: base material 112, 122: circumferential surface 114, 124: side surface 116: opening 120: sintered body 130: bonding material 140: protective member 150, 160: space

Claims (7)

A cylindrical sintered body;
A cylindrical base material joined to the inside of the sintered body via a joining material;
A protective member that covers openings at both ends of the base material and seals the hollow portion of the base material filled with gas;
A cylindrical sputtering target comprising:   The cylindrical sputtering target according to claim 1, wherein the gas is argon or nitrogen.   The cylindrical sputtering target according to claim 1 or 2, wherein the pressure of the gas in the space is 30 kPa or more and 60 kPa or less.   4. The cylindrical sputtering target according to claim 1, wherein a dew point temperature of the gas in the space is −80 ° C. or more and −50 ° C. or less. 5.   The cylindrical sputtering target according to any one of claims 1 to 4, wherein the sintered body contains ITO, IZO, or IZGO as a main component. A cylindrical sputtering target packing method comprising: a cylindrical sintered body; and a cylindrical base material joined to the inside of the sintered body via a joining material,
Filling the hollow part of the base material with gas,
A method of packing a cylindrical sputtering target, wherein a protective member is formed so as to cover openings at both ends of the substrate and to seal the hollow portion. Before filling the gas,
Exhausting the gas in the hollow,
Introducing an inert gas into the exhausted hollow portion;
The method for packing a cylindrical sputtering target according to claim 6, wherein the inert gas is exhausted.

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