TWI692539B - Sputtering target and its packaging method - Google Patents

Abstract

The present invention provides a sputtering target that suppresses damage to the end of a cylindrical backing tube. The sputtering target has: a cylindrical sputtering target (110); a cylindrical backing tube (120) that is joined to the inside of the cylindrical sputtering target (110) by a bonding material, and the cylindrical type The length of the backing tube in the direction of the central axis (C) is longer than the length of the cylindrical sputtering target (110) in the direction of the central axis (C); and the protective cover (130) covering the cylindrical back At least one end (121) of the liner (120) in the direction of the central axis (C); the protective cover (130) contains synthetic resin.

Description

Sputtering target and its packaging method

The invention relates to a sputtering target and its packaging method.

In recent years, the manufacturing technology of flat panel displays (FPD: Flat Panel Display) and the manufacturing technology of solar cells have developed rapidly, and the market for large thin TVs and solar cells is becoming larger. In addition, with the development of these markets, in order to reduce the manufacturing cost of products, glass substrates are gradually becoming larger. Currently, a device for the 2200mm×2400mm size called the eighth generation is being developed.

In particular, in a sputtering apparatus in which a metal thin film or a metal oxide thin film is formed on a large-sized glass substrate, a flat-plate type sputtering target or a cylindrical type (also referred to as a rotary type or rotary type) sputtering target is used. Compared with a flat type sputtering target, a cylindrical type sputtering target has advantages of high efficiency of use of the target, less occurrence of corrosion, and less generation of particles due to peeling of the deposit. In this way, the cylindrical sputtering target is very useful in the application of thin film formation.

Therefore, with the development of transportation and means of transportation, the above-mentioned cylindrical sputtering targets are not only shipped domestically but also overseas. Therefore, a method that does not damage the cylindrical sputtering target product in consideration of the transportation distance, transportation means, environment, etc. is desired.

For example, Patent Document 1 discloses a cylindrical sputtering target having: a cylindrical sintered body; a cylindrical base material that is bonded to the inside of the sintered body by a bonding material; and a protective member (protective film) , Covering the openings at both ends of the base material, and sealing the hollow portion of the base material filled with gas.

Existing technical literature

Patent Literature

Patent Literature 1: Japanese Patent Application Publication No. 2017-179464

Problems to be solved by the invention

Both ends of the base material included in the cylindrical sputtering target are provided with sealing surfaces on the inner peripheral surface side so that cooling water for cooling the heat generated in sputtering can be introduced. Therefore, during the transportation of the cylindrical sputtering target, it is necessary to avoid damaging the sealing surface. In addition, it is also necessary to suppress deformation of both ends of the base material. Therefore, it is particularly desirable to protect the end of the substrate.

For example, in the cylindrical sputtering target disclosed in Patent Document 1, since dust or moisture from the outside does not adhere to the target surface, it is possible to suppress arcing during sputtering. However, this Patent Document 1 does not mention protecting the end of the base material from mechanical impact. Therefore, due to the mechanical impact generated during transportation, both end portions of the base material may contact the inner wall of the packaging box to cause damage to the sealing surface, or deform the end portion of the base material. When the cylindrical sputtering target is used in a sputtering device, there is a problem that cooling water leaks during sputtering or cannot be installed in the sputtering device. In this way, the method for protecting the end of the base material (cylindrical backing tube) still has room for improvement.

Therefore, the present invention has been made in view of the above circumstances, and its object is to provide a sputtering target capable of suppressing damage to the end of a cylindrical backing tube and a packaging method thereof.

Means for solving problems

That is, in one aspect, the present invention provides a sputtering target having: a cylindrical sputtering target; a cylindrical backing tube that is bonded to the inside of the cylindrical sputtering target by a bonding material, and The length of the cylindrical backing tube in the direction of the central axis is longer than the length of the cylindrical sputtering target in the direction of the central axis; and a protective cover covering the center of the cylindrical backing tube At least one end in the axial direction; the protective cover contains synthetic resin.

In one embodiment of the sputtering target of the present invention, the protective cover covers both ends of the cylindrical backing tube in the direction of the central axis.

In one embodiment of the sputtering target of the present invention, one end of the protective cover in the axial direction forms a concave notch in the circumferential direction, and at least at least one of the cylindrical backing tubes in the direction of the central axis One end is inserted into the notch.

In one embodiment of the sputtering target of the present invention, the gap between the outer inner circumferential surface of the notch and the outer circumferential surface of the end of the cylindrical backing tube in the direction of the central axis is 0.1 mm Above and less than 1.0mm.

In one embodiment of the sputtering target of the present invention, the notch portion abuts the end surface, the outer peripheral surface, and the inner peripheral surface of the end of the cylindrical backing tube.

In one embodiment of the sputtering target of the present invention, the protective cover further covers the end of the cylindrical sputtering target in the direction of the central axis.

In one embodiment of the sputtering target of the present invention, the synthetic resin is selected from silicone rubber, Viton rubber, fluororubber, butyl rubber, acrylic rubber, ethylene propylene rubber, urethane rubber, polyesters Elastomers, polyolefin elastomers, fluorine elastomers, silicon elastomers, butadiene elastomers, polyamide elastomers, polystyrene elastomers, urethane elastomers, polyurethane resins , Flexible epoxy resin, fluororesin, polycarbonate, polypropylene, polyethylene, polyethylene terephthalate, and polyethylene naphthalate.

In one embodiment of the sputtering target of the present invention, the synthetic resin is polytetrafluoroethylene.

In one embodiment of the sputtering target of the present invention, the wall thickness of the protective cover is 2.0 mm or more.

In one embodiment of the sputtering target of the present invention, the wall thickness of the protective cover is 5.0 mm or less.

In one embodiment of the sputtering target of the present invention, the protective cover has a Young's modulus of 2000 MPa or less.

In one embodiment of the sputtering target of the present invention, the cylindrical sputtering target contains one selected from the group consisting of ITO, ZnO, IZO, and IGZO as a main component.

In one embodiment of the sputtering target of the present invention, a plurality of the cylindrical sputtering targets are arranged coaxially.

In addition, in another aspect, the present invention provides a sputtering target packaging method for packaging the above sputtering target, including: adjusting the inside of the hollow portion of the cylindrical backing tube to an inert gas environment or A step of a vacuum environment; and a step of forming a protective film so as to cover the openings at both ends of the cylindrical backing tube and seal the inside of the hollow portion.

In one embodiment of the sputtering target packaging method of the present invention, the pressure of the inert gas inside the hollow portion is 30 kP to 60 kPa.

In one embodiment of the method for packaging a sputtering target of the present invention, the inert gas is argon or nitrogen.

In one embodiment of the method for packaging a sputtering target of the present invention, the inert gas inside the hollow portion has a dew point temperature of -80°C to -50°C.

Effect of invention

According to an embodiment of the present invention, damage to the end of the cylindrical backing tube can be suppressed.

In the following, the present invention is not limited to each embodiment, and the constituent elements can be modified and embodied without departing from the gist thereof. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiments. For example, some constituent elements may be deleted from all the constituent elements shown in the embodiment. Furthermore, the components of different embodiments may be combined as appropriate. In addition, the sputtering target of the present invention refers to a sputtering target with a protective cover. The inventors of the present invention conducted intensive studies and found that by having a protective cover for covering at least one end portion of the cylindrical backing tube in the direction of the central axis and making the protective film contain a synthetic resin, the cylindrical back can be suppressed Damage to the end of the liner.

Hereinafter, an embodiment of the sputtering target of the present invention will be exemplified.

[1. Sputtering target]

An embodiment of the sputtering target of the present invention will be described using the drawings. FIG. 1A is a schematic cross-sectional view for explaining an embodiment of the sputtering target of the present invention. FIG. 1B is an enlarged view for explaining the protective cover shown in FIG. 1A and its surroundings. FIG. 1C is an enlarged view for explaining the protective cover shown in FIG. 1A. FIG. 2 is a cross-sectional view taken along X-X in FIG. 1A. 3 is a schematic cross-sectional view showing an example of a protective cover as an embodiment of the sputtering target of the present invention. 4 is a schematic cross-sectional view showing another example of a protective cover as an embodiment of the sputtering target of the present invention. FIG. 5 is a schematic cross-sectional view showing another example of the protective cover as an embodiment of the sputtering target of the present invention. 6 is a schematic cross-sectional view for explaining another embodiment of the sputtering target of the present invention. 7 is a schematic cross-sectional view showing another example of a protective cover as an embodiment of the sputtering target of the present invention.

As shown in FIG. 1A, the sputtering target 100 includes a cylindrical sputtering target 110 and a cylindrical backing tube 120 that is joined to the inside of the cylindrical sputtering target 110 by a bonding material. The length of the backing tube in the direction of the central axis C is longer than the length of the cylindrical sputtering target 110 in the direction of the central axis C; and the protective cover 130 covers the central axis C of the cylindrical backing tube 120 The two ends 121 in the direction. In addition, the protective cover 130 contains synthetic resin. Thereby, the sealing surface of the inner peripheral surface 121 a near the end 121 of the backing tube 120 is not damaged, and the deformation of the end 121 can be suppressed.

(Cylindrical sputtering target)

The cylindrical sputtering target 110 is provided so as to surround the outer peripheral surface 120 b of the cylindrical backing tube 120. Preferably, the cylindrical sputtering target 110 is provided coaxially or substantially coaxially with the central axis C of the cylindrical backing tube 120. With such a configuration, when the sputtering target 100 is mounted on a sputtering device and rotated around the cylindrical backing tube 120, the surface of the cylindrical sputtering target 110 and the film-forming surface (sample The interval between substrates) remains constant.

The cylindrical sputtering target 110 is formed into a hollow cylindrical shape. The relative density of the cylindrical sputtering target 110 is preferably 99.0% or more, and more preferably 99.7% or more. In addition, in the present invention, the relative density is calculated by the Archimedes method. In addition, from the viewpoint of suppressing abnormal discharge during sputtering, it is preferable that the average surface roughness (Ra) of the cylindrical sputtering target 110 is less than 0.5 μm.

Furthermore, the material of the cylindrical sputtering target 110 is not particularly limited as long as it can be sputter-formed, and examples thereof include metal oxides, metal nitrides, and metal oxynitride sintered bodies. As the metal oxide, oxides of metals belonging to typical elements such as indium oxide, tin oxide, zinc oxide, and 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, oxide A compound selected from a compound of zinc and gallium oxide (Indium Gallium Zinc Oxide: IGZO) is used as the cylindrical sputtering target 110.

(Cylindrical backing pipe)

The cylindrical backing tube 120 forms a hollow portion V1 having a hollow structure on the side of the inner peripheral surface 120a. The cylindrical backing tube 120 has an outer surface shape along the inner peripheral surface 110a of the cylindrical sputtering target 110, for example. The outer diameter of the cylindrical backing tube 120 is slightly smaller than the inner diameter of the cylindrical sputtering target 110. When the cylindrical backing tube 120 and the cylindrical sputtering target 110 are coaxially superimposed, it is adjusted to A gap can be formed between the cylindrical backing tube 120 and the cylindrical sputtering target 110. The bonding material is provided in this gap.

The cylindrical backing tube 120 is preferably a metal that has good wettability with the bonding material and has high bonding strength with the bonding material. For example, as a material constituting the cylindrical backing tube 120, copper (Cu) or titanium (Ti), or copper alloy, titanium alloy, or stainless steel (SUS) is preferably used. As the copper alloy, an alloy containing copper (Cu) as a main component such as chromium copper can be used. In addition, if titanium (Ti) is used as the cylindrical backing tube 120, a lightweight and rigid cylindrical backing tube 120 can be obtained.

(protection cap)

As shown in FIGS. 1B and 1C, the protective cover 130 has a cylindrical shape, forms a hollow portion V2 having a hollow structure on the inner inner peripheral surface 133 b side, and has a concave notch portion 131 along the circumferential direction. The end 121 of the cylindrical backing tube 120 is inserted into the notch 131 of the protective cover 130. This protects the end 121 of the cylindrical backing tube 120 from deformation or protects the sealing surface of the inner circumferential surface 121 a of the end 121 of the cylindrical backing tube 120. The notch 131 preferably contacts the end surface 121 b, the outer peripheral surface 121 c, and the inner peripheral surface 121 a of the end 121 of the cylindrical backing tube 120. Thus, the protective cover 130 is not detached from the end 121 of the cylindrical backing tube 120 due to vibration generated during transportation. Therefore, even if the sputtering target 100 is stored in the packaging box, the end 121 of the cylindrical backing tube 120 does not directly hit the inner wall of the packaging box, and damage or friction can be suppressed. In addition, the raised surface 131 b of the protective cover 130 is in contact with the end surface 111 a of the end 111 of the cylindrical sputtering target 110. Thus, damage to the end 111 of the cylindrical sputtering target 110 can be suppressed.

From the viewpoint of ensuring the strength of the protective cover 130, the wall thicknesses D1 to D3 of the protective cover 130 are preferably 2.0 mm or more, more preferably 2.5 mm or more, and still more preferably 3.0 mm or more. In addition, considering the packaging of the sputtering target 100, each is preferably 5.0 mm or less, more preferably 4.5 mm or less, and still more preferably 4.0 mm or less. Here, as shown in FIG. 2, D1 refers to the distance between the outer peripheral surface 132 a and the outer inner peripheral surface 132 b of the protective cover 130 on a line Lv extending radially outward from the central axis C of the protective cover 130, D2 refers to the distance between the inner outer peripheral surface 133a of the protective cover 130 and the inner inner peripheral surface 133b of the protective cover 130. In addition, as shown in FIG. 1B, D3 refers to the distance from the concave surface 131 a to the end surface 134 of the protective cover 130 parallel to the central axis C.

As shown in FIG. 3, it is preferable that the protective cover 130 is provided with a gap W between the outer inner peripheral surface 132 b of the notch 131 and the outer peripheral surface 121 c of the end 121 of the cylindrical backing tube 120 in the direction of the central axis C. From the viewpoint of easy removal of the protective cover 130 from the end 121 of the cylindrical backing tube 120, the gap W is preferably 0.1 mm or more, more preferably 0.25 mm or more, and still more preferably 0.3 mm or more. However, considering that the protective cover 130 does not come off due to vibration generated when transporting the sputtering target 100, the gap W is preferably less than 1.0 mm, more preferably 0.8 mm or less, and still more preferably 0.5 mm or less. Here, W refers to the outer circumference of the protective cap 130 extending from the central axis C of the protective cap 130 to the radially outer side from the outer inner peripheral surface 132b of the protective cap 130 to the end 121 of the cylindrical backing tube 120 The distance between the faces 121c. In addition, from the viewpoint of protecting the sealing surface of the backing tube 120, the inner peripheral surface 133 a of the notch 131 abuts the inner peripheral surface 121 a of the end 121 of the backing tube 120 in the direction of the central axis C.

In addition, as shown in FIG. 4, it is preferable that the protective cover 130 partially covers the end 121 of the cylindrical backing tube 120. That is, the end surface 111 a of the end 111 of the cylindrical sputtering target 110 is separated from the raised surface 131 b of the protective cover 130 by a distance L. From the viewpoint of protecting the end 121 of the cylindrical backing tube 120, the distance L is preferably 5.0 mm or less.

As shown in FIGS. 5 and 6, it is preferable that the protective cover 130 further covers the end 111 of the cylindrical sputtering target 110 in the direction of the central axis C. In FIG. 5, a stepped surface 131 b 1 is formed in the notch portion 131 of the protective cover 130, and this stepped surface 131 b 1 abuts on the end surface 111 a of the cylindrical sputtering target 110. The protective cover 130 extends parallel to the central axis C along the inner peripheral surface 111 b and the outer peripheral surface 111 c of the end portion 111 of the cylindrical sputtering target 110. At this time, preferably, in the protective cover 130, the distance d1 between the raised surface 131b and the same position as the stepped surface 131b1 of the protective cover 130 parallel to the central axis C is 20 mm or less. Thereby, not only the damage and deformation of the end 121 of the cylindrical backing tube 120 but also the damage and deformation of the end 111 of the cylindrical sputtering target 110 can be prevented more reliably. In addition, in this protective cover 130, in order to reduce the mechanical impact, from the outer circumferential surface 111c of the end 111 of the cylindrical sputtering target 110 to the outer periphery of the protective cover 130 on a line extending radially outward from the central axis C The distance d2 between the surfaces 132a is preferably 3 mm or more. Furthermore, as shown in FIG. 6, when the protective cover 130 is covered on the end 121 of the cylindrical backing tube 120, the protective cover 130 extends from the outer circumferential surface 121 c of the end 121 of the cylindrical backing tube 120 to the protective cover The hollow portion V3 formed between the outer inner peripheral surfaces 132b of 130. Therefore, it is preferable that the protective cover 130 extends along a part of the inner peripheral surface 120 a of the cylindrical backing tube 120 from the viewpoint of not detaching the protective cover 130 due to vibration generated when transporting the sputtering target 100.

In addition, as shown in FIG. 7, the protective cover 130 has a cylindrical shape, and a concave cutout 131 for covering the end 121 of the backing tube 120 is formed. Since the protective cap 130 does not form a hollow portion, the hollow portion V1 of the cylindrical backing tube 120 is sealed. In such a case, in consideration of vacuum exhaust when packaging the sputtering target 100, it is preferable to form a through hole H (for example, φ5 mm or less) in the central axis C direction at the central portion of the protective cover 130. When the sputtering target 100 is packaged, the through hole H constitutes a gas flow path that discharges the gas in the hollow portion V1 of the cylindrical backing tube 120 or supplies the gas to the hollow portion V1 from the outside.

The material of the protective cover 130 contains a synthetic resin that is resistant to external impact, and examples thereof include silicone rubber, Viton rubber, fluororubber, butyl rubber, acrylic rubber, ethylene propylene rubber, and urethane rubber. , Polyester elastomer, polyolefin elastomer, fluorine elastomer, silicon elastomer, butadiene elastomer, polyamide elastomer, polystyrene elastomer, urethane Ethyl elastomer, polyurethane resin, flexible epoxy resin, fluororesin, polycarbonate, polypropylene, polyethylene, polyethylene terephthalate and polyethylene naphthalate. One of these may be used alone, or two or more kinds may be used in combination. Among them, as the material of the protective cover 130, polytetrafluoroethylene is preferably chemically stable and excellent in heat resistance, so polytetrafluoroethylene is preferable.

From the viewpoint of alleviating external impact, the Young's modulus of the protective cover 130 is preferably 2500 MPa or less, more preferably 2000 MPa or less, and still more preferably 1600 MPa or less. In addition, in the present invention, the Young's modulus of the protective cover 130 is measured according to JIS K7127:1999.

(Joint material)

The bonding material is provided between the cylindrical backing tube 120 and the cylindrical sputtering target 110. The bonding material is formed as the bonding layer 140 between them. It is preferable that the joining material joins the cylindrical backing tube 120 and the cylindrical sputtering target 110 and has good heat resistance and thermal conductivity. In addition, since it is placed under vacuum during sputtering, it is preferable to have a characteristic of less gas evolution in vacuum.

Furthermore, from the viewpoint of manufacturing, it is preferable that the joining material has fluidity when joining the cylindrical backing tube 120 and the cylindrical sputtering target 110. In order to satisfy these characteristics, as the bonding material, a low-melting metal material having a melting point of 300° C. or lower can be used. For example, as the bonding material, a metal such as indium (In), tin (Sn), or a metal alloy material containing any of these elements can be used. Specifically, a simple substance of indium or tin, an alloy of indium and tin, a solder alloy mainly composed of tin, or the like can be used.

For example, as shown in FIG. 8, in the sputtering target 200, a plurality of cylindrical sputtering targets 210 are arranged coaxially, and are joined to the cylindrical backing tube 120 by a joining material. In addition, both end portions 121 of the cylindrical backing tube 120 are covered by the protective cover 130. In addition, by providing a sheet member such as a buffer material in the space 215 between the adjacent cylindrical sputtering targets 210, it is possible to suppress the end 211 of the cylindrical sputtering target 210 from being damaged by mechanical impact caused by transportation or the like Or deformed.

[2. Manufacturing method of sputtering target]

Next, an embodiment of the method for manufacturing a sputtering target of the present invention will be described using the drawings. 9 is a flowchart showing an outline of an embodiment of a method of manufacturing a sputtering target of the present invention.

In one embodiment of the method for manufacturing a sputtering target of the present invention, an example in which an indium tin oxide (ITO) sintered body is used as a sintered body is shown, but the material of the sintered body is not limited to ITO, and ZnO, IZO, IGZO and other metal oxide compounds.

First, the raw materials constituting the sintered body are prepared. In this embodiment, indium oxide powder and tin oxide powder are prepared (S11, S12). The purity of these raw materials may generally be 2N (99 mass%) or more, preferably 3N (99.9 mass%) or more, and more preferably 4N (99.99 mass%) or more. If the purity is lower than 2N, the sintered body contains a lot of impurities, so that the desired physical properties (for example, the transmittance of the formed thin film is decreased, the resistance value is increased, and particles are generated due to arcing) are generated.

Next, the powders of these raw materials are pulverized and mixed (S13). For the pulverization and mixing treatment of the raw material powder, a dry method using balls or beads (so-called media) such as zirconia, alumina, nylon resin, etc., or a media agitating mill using the balls or beads, medium-free Wet method of container rotary grinder, mechanical stirring grinder, airflow grinder, etc. Here, in general, the wet method is superior to the dry method in terms of pulverization and mixing ability, so it is preferable to use the wet method for mixing.

The composition of the raw material is not particularly limited, but it is preferably adjusted appropriately according to the composition ratio of the target sintered body.

Next, the slurry of the raw material powder is dried and granulated (S13). At this time, the slurry may be quickly dried using quick drying granulation. Quick drying granulation can be performed by adjusting the temperature or air volume of hot air using a spray dryer.

Next, the mixture obtained by the above mixing and granulation (the mixture temporarily fired when provisionally fired is provided) is pressure-molded to form a cylindrical shaped body (S14). Through this process, the shape is shaped to fit the target sintered body. Examples of the molding process include mold molding, injection molding, and injection molding. However, in order to obtain a complicated shape like a cylindrical shape, molding by cold isostatic pressing (CIP) or the like is preferred. The pressure for molding 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 can be formed. By making the relative density of the molded body within the above range, the relative density of the sintered body obtained by the subsequent sintering can be 99.7% or more.

Next, the cylindrical molded body obtained by the molding step is sintered (S15). An electric furnace is used for sintering. The sintering conditions can be appropriately selected according to the composition of the sintered body. For example, in the case of ITO containing 10% by mass of SnO 2, it can be sintered by leaving it at a temperature of 1400° C. or more and 1600° C. or less for 10 hours or more and 30 hours or less in an oxygen gas atmosphere. When the sintering temperature is lower than the lower limit, the relative density of the sintered body will decrease. On the other hand, if it exceeds 1600°C, damage to the electric furnace and furnace materials is large and frequent maintenance is required, so the work efficiency is significantly reduced. In addition, when the sintering time is shorter than the lower limit, the relative density of the sintered body may decrease. In addition, the pressure during sintering may be atmospheric pressure or a pressurized environment.

Next, the formed cylindrical sintered body is machined into a desired shape of a cylindrical shape by a mechanical processing machine such as a surface grinder, a cylindrical grinder, a lathe, a cutting machine, a machining center (S16) ). The mechanical processing performed here is a step of processing a cylindrical sintered body to have a desired shape and surface roughness, and finally, through this step, a cylindrical sputtering target 110 is formed.

Next, the mechanically processed cylindrical sputtering target 110 is subjected to ultrasonic cleaning treatment in pure water to remove the machined abrasive debris adhering to the surface of the cylindrical sputtering target 110. Next, the cylindrical sputtering target 110 and the cylindrical backing tube 120 are bonded by a bonding material (S17). For example, when indium is used as a bonding material, molten indium is injected into the gap between the cylindrical sputtering target 110 and the cylindrical backing tube 120. In this way, the cylindrical sputtering target 100 can be obtained.

Next, at least one end 121 of the cylindrical backing tube 120 included in the cylindrical sputtering target 100 in the direction of the central axis C covers the protective cover 130 (S18). The molding method of the protective cover 130 is not particularly limited, but examples include injection molding (including insert molding, hollow molding, multi-color molding, etc.), blow molding, compression molding, and extrusion molding.

In this way, a cylindrical sputtering target 100 with a protective cover can be obtained.

[3. Packaging method of sputtering target]

Next, one embodiment of the sputtering target packaging method of the present invention will be described with reference to the drawings. FIG. 10 is a flowchart showing an outline of an embodiment of the sputtering target packaging method of the present invention. 11 is a schematic cross-sectional view showing a sputtering target packaged by an embodiment of the sputtering target packaging method of the present invention.

As shown in FIG. 10, one embodiment of the sputtering target packaging method of the present invention includes the step S21 of adjusting the inside of the hollow portion V1 of the cylindrical backing tube 120 to an inert gas atmosphere or a vacuum environment; and a step In S22, the protective film 150 is formed so as to cover the openings of both ends 121 of the cylindrical backing tube 120 and seal the inside of the hollow portion V1 of the backing tube 120.

(Inactive environment)

In order to replace the gas present in the hollow portion V1 of the cylindrical backing tube 120 with a desired gas, the gas in the hollow portion V1 is exhausted, and an inert gas is introduced into the exhausted hollow portion V1. Then, after the inert gas introduced into the hollow portion V1 is discharged, the hollow portion V1 is filled with the above gas. In addition, the exhaust of the gas in the hollow portion V1 and the introduction of the inert gas may be repeated multiple times. Thereby, the purity of the gas filled in the hollow portion V1 can be made close to the purity of the supplied gas. As a result, the space can be filled with high-quality gas with little dust and moisture. Then, as shown in FIG. 11, the sputtering target 100 is packaged with the protective film 150 in a state filled with gas.

As the gas filled in the hollow portion V1, for example, argon gas (Ar) or nitrogen gas (N2) can be used. In consideration of the difference between the pressure of the hollow portion V1 and the external atmospheric pressure, the pressure of the gas filled in the hollow portion V1 is preferably 30 kPa or more, and more preferably 40 kPa or more. In addition, considering the volume expansion of the gas during transportation such as air transportation, the pressure of the gas is preferably 60 kPa or less, and more preferably 50 kPa or less.

In addition, it is preferable that the amount of moisture in the hollow portion V1 is small. That is, from the viewpoint of suppressing condensation on the inside of the protective film 150 due to the storage environment, the dew point temperature of the gas filled in the hollow portion V1 is preferably -80°C to -50°C. By doing so, condensation does not form inside the protective film 150, and when the sputtering target 100 is used, a film can be formed without causing arcing or the like.

(Protective film)

The protective film 150 uses a film-shaped resin. As a material of the protective film 150, a laminated film obtained by laminating a plurality of films of different properties can be used. For example, a laminate film formed by sandwiching a functional film between two polyethylene films can be used. For the polyethylene film, a material whose melting temperature under heating is lower than that of the functional film can be used. Due to the structure in which the functional film is sandwiched by the polyethylene film, the polyethylene films are reliably melted with each other during heat sealing, so that the protective film can be reliably sealed. It is preferable that at least one of the oxygen permeability and moisture permeability of the functional film is lower than that of the polyethylene film. In addition, it is preferable that at least one of the puncture strength and the tensile strength of the functional film is higher than that of the polyethylene film.

Specifically, as the functional film, UNLION (Union: registered trademark) manufactured by Idemitsu Unitech can be used, preferably, Saran Wrap (registered trademark) manufactured by Asahi Kasei can be used, and more preferably, Kuraray ( KURARAY) manufactured EVOH (エバール: registered trademark) film. Here, the physical properties of UNLION, Saran Wrap, and EVOH films are as follows. In addition, the functional film is not limited to the following films, and various films can be used according to different purposes.

[UNLION]

Oxygen permeability (20℃ 90%RH): 37cc/d·atm

Moisture permeability (40℃ 90%RH): 90g/m2·day

Puncture strength: 16.0kgf (10.9×10-3MPa)

Tensile strength: 260MPa

[Saran Wrap]

Oxygen permeability (20℃ 90%RH): 60cc/d·atm

Moisture permeability (40℃ 90%RH): 12g/m2·day

Tensile strength: 470MPa

[EVOH film]

Oxygen permeability (20℃ 90%RH): 30cc/d·atm

Moisture permeability (40℃ 90%RH): 5.3g/m2·day

Puncture strength: 11.1kgf (10.9×10-3MPa)

Tensile strength: 40MPa

[Example]

The present invention will be specifically described based on Examples and Comparative Examples. The descriptions of the following examples and comparative examples are only specific examples for easily understanding the technical content of the present invention, and the technical scope of the present invention is not limited by these specific examples. In addition, description will be made using FIG. 12, which is an enlarged view illustrating the protective cover of the sputtering target assembled in Examples 1 to 7 and Comparative Examples 1 to 3 and its surroundings.

(Example 1)

First, three cylindrical sputtering targets 210 described below and one cylindrical backing tube 120 described below are prepared. The cylindrical backing tube 120 was joined to the inside of the cylindrical sputtering target 210 by a joining material so that the outer peripheral surface 121c of the end 121 of the cylindrical backing tube was exposed by 9 mm in the direction of the central axis C ，Assemble into a sputtering target 200.

<Cylindrical sputtering target>

The axial length of the cylinder: 243mm

Cylinder outer diameter: 153mm

Inner diameter of cylinder: 135mm

Material: Indium Tin Oxide (ITO)

＜Cylinder type backing pipe＞

The axial length of the cylinder: 785mm

Cylinder outer diameter: 133mm

Cylinder inner diameter: 126mm

Material: Titanium (Ti)

<Joint material>

Material: Indium (In)

Next, as shown in Table 1, a protective cover was produced in the following manner so that the average thickness D1 to D3 of the protective cover 130 made of polypropylene was 3 mm, respectively. In addition, the protective cover 130 is manufactured by injection molding.

At both end portions 121 of the cylindrical backing tube 120 in the direction of the central axis C, the protective cover 130 is covered so that the gap W is 0.3 mm. Then, the sputtering target 200 was evaluated as follows.

<drop test>

First, an aluminum plate (300 mm long×300 mm wide×10 mm thick) covered with a urethane material having a thickness of 20 mm is prepared. Next, the end surface 121b of the backing tube 120 is dropped toward the plate in the direction of the central axis C from a position having a height of 300 mm from the plate. Next, the dropped sputtering target is recovered, the protective cover 130 is removed, and the end 121 of the cylindrical backing tube 120 and the end 211 of the cylindrical sputtering target 210 are visually observed. Table 1 shows the results.

(Example 2)

As shown in Table 1, the evaluation was performed in the same manner as in Example 1, except that the gap W was changed to 0.1 mm. In addition, the evaluation results are shown in Table 1.

(Example 3)

As shown in Table 1, the evaluation was performed in the same manner as in Example 1 except that the thicknesses D1 to D3 of the protective cover 130 were changed to 5 mm, respectively. In addition, the evaluation results are shown in Table 1.

(Example 4)

As shown in Table 1, the evaluation was performed in the same manner as in Example 1 except that the material of the protective cover 130 was changed to polytetrafluoroethylene (PTFE). In addition, the evaluation results are shown in Table 1.

(Example 5)

As shown in Table 1, the evaluation was performed in the same manner as in Example 1 except that the material of the protective cover 130 was changed to silicone rubber. In addition, the evaluation results are shown in Table 1.

(Example 6)

As shown in Table 1, the evaluation was performed in the same manner as in Example 1, except that the material of the protective cover 130 was changed to urethane rubber. In addition, the evaluation results are shown in Table 1.

(Example 7)

As shown in Table 1, the evaluation was performed in the same manner as in Example 1 except that the cylindrical sputtering target 210 was changed to IZO. In addition, the evaluation results are shown in Table 1.

(Comparative example 1)

As shown in Table 1, the evaluation was performed in the same manner as in Example 1, except that the gap W was changed to 1.0 mm. In addition, the evaluation results are shown in Table 1.

(Comparative example 2)

As shown in Table 1, the evaluation was performed in the same manner as in Example 1 except that the thicknesses D1 to D3 of the protective cover 130 were changed to 1 mm, respectively. In addition, the evaluation results are shown in Table 1.

(Comparative example 3)

As shown in Table 1, the evaluation was performed in the same manner as in Example 1, except that the material of the protective cover 130 was changed to stainless steel (SUS). In addition, the evaluation results are shown in Table 1.

[Table 1]

According to Table 1, in Examples 1 to 7, it was confirmed that in the drop test, the sealing surface on the inner peripheral surface side of the end of the backing tube was not damaged, and the end of the backing tube was not deformed. Furthermore, it was confirmed that the end of the cylindrical sputtering target was not damaged or deformed. Therefore, it can be said that it is useful to cover the protective cover at the end of the cylindrical backing tube and that the protective cover contains synthetic resin.

[this invention] 100、200‧‧‧Sputtering target 110、210‧‧‧Cylinder sputtering target 110a‧‧‧Inner peripheral surface 111、211‧‧‧End 111a‧‧‧End 111b‧‧‧Inner peripheral surface 111c‧‧‧Peripheral surface 120‧‧‧Cylinder type backing tube 120a‧‧‧Inner peripheral surface 120b‧‧‧Perimeter 121‧‧‧End 121a‧‧‧Inner peripheral surface 121b‧‧‧End 121c‧‧‧Perimeter 130‧‧‧Protection cover 131‧‧‧Notch 131a‧‧‧Concave 131b‧‧‧raised face 131b1‧‧‧step surface 132a‧‧‧Outer peripheral surface 132b‧‧‧Outer inner circumferential surface 133a‧‧‧Inner peripheral surface 133b‧‧‧Inner inner circumferential surface 134‧‧‧End 140‧‧‧Joint layer 150‧‧‧Protection film C‧‧‧Central axis D1 to D3 ‧‧‧ wall thickness d1, d2‧‧‧Distance H‧‧‧Through hole L‧‧‧Distance Lv‧‧‧line V1, V2 ‧‧‧ Hollow Department W‧‧‧clearance

FIG. 1A is a schematic cross-sectional view for explaining an embodiment of the sputtering target of the present invention. FIG. 1B is an enlarged view illustrating the protective cover shown in FIG. 1A and its surroundings. FIG. 1C is an enlarged view illustrating the protective cover shown in FIG. 1A. FIG. 2 is a cross-sectional view taken along X-X in FIG. 1A. 3 is a schematic cross-sectional view showing an example of a protective cover as an embodiment of the sputtering target of the present invention. 4 is a schematic cross-sectional view showing another example of a protective cover as an embodiment of the sputtering target of the present invention. FIG. 5 is a schematic cross-sectional view showing another example of the protective cover as an embodiment of the sputtering target of the present invention. 6 is a schematic cross-sectional view showing another example of a protective cover as an embodiment of the sputtering target of the present invention. 7 is a schematic cross-sectional view showing another example of a protective cover as an embodiment of the sputtering target of the present invention. 8 is a schematic cross-sectional view for explaining another embodiment of the sputtering target of the present invention. 9 is a flowchart showing an outline of an embodiment of a method of manufacturing a sputtering target of the present invention. FIG. 10 is a flowchart showing an outline of an embodiment of the sputtering target packaging method of the present invention. 11 is a schematic cross-sectional view showing a sputtering target packaged by an embodiment of the sputtering target packaging method of the present invention. 12 is an enlarged view for explaining the protective cover of the sputtering target assembled in Examples 1 to 7 and Comparative Examples 1 to 3 and its surroundings.

100‧‧‧Sputtering target

110‧‧‧Cylinder sputtering target

111‧‧‧End

111a‧‧‧End

120‧‧‧Cylinder type backing tube

121‧‧‧End

121a‧‧‧Inner peripheral surface

121b‧‧‧End

121c‧‧‧Perimeter

130‧‧‧Protection cover

131‧‧‧Notch

131a‧‧‧Concave

131b‧‧‧raised face

132a‧‧‧Outer peripheral surface

132b‧‧‧Outer inner circumferential surface

133a‧‧‧Inner peripheral surface

133b‧‧‧Inner inner circumferential surface

134‧‧‧End

140‧‧‧Joint layer

C‧‧‧Central axis

D1 to D3 ‧‧‧ wall thickness

V1, V2 ‧‧‧ Hollow Department

Claims (21)

A sputtering target includes: a cylindrical sputtering target; a cylindrical backing tube, which is joined to the inside of the cylindrical sputtering target by a bonding material, and the cylindrical backing tube is at the center The length in the axial direction is longer than the length of the cylindrical sputtering target in the central axis direction; and a protective cover covering at least one end of the cylindrical backing tube in the central axis direction; the protection The cover contains a synthetic resin. The sputtering target according to claim 1, wherein the protective cover covers both ends of the cylindrical backing tube in the direction of the central axis. The sputtering target according to claim 1, wherein one end of the protective cover in the axial direction forms a concave notch in the circumferential direction, and the at least one end of the cylindrical backing tube in the direction of the central axis Part is inserted into the notch. The sputtering target according to claim 2, wherein one end of the protective cover in the axial direction forms a concave notch in the circumferential direction, and the at least one end of the cylindrical backing tube in the direction of the central axis Part is inserted into the notch. The sputtering target according to claim 3, wherein a gap between an outer inner peripheral surface of the notch portion and an outer peripheral surface of the end portion of the cylindrical backing tube in the direction of the central axis is 0.1 mm Above and less than 1.0mm. The sputtering target according to claim 4, wherein a gap between an outer inner peripheral surface of the notch portion and an outer peripheral surface of the end portion of the cylindrical backing tube in the direction of the central axis is 0.1 mm Above and less than 1.0mm. The sputtering target according to claim 3, wherein the notch portion abuts an end surface, an outer peripheral surface, and an inner peripheral surface of the end portion of the cylindrical backing tube. The sputtering target according to claim 4, wherein the notch portion abuts an end surface, an outer peripheral surface, and an inner peripheral surface of the end portion of the cylindrical backing tube. The sputtering target according to claim 3, wherein the protective cover also covers the end of the cylindrical sputtering target in the direction of the central axis. The sputtering target according to claim 4, wherein the protective cover also covers the end of the cylindrical sputtering target in the direction of the central axis. The sputtering target according to any one of claims 1 to 10, wherein the synthetic resin is made of silicone rubber, Viton rubber, fluororubber, butyl rubber, acrylic rubber, ethylene propylene rubber, urethane rubber, Polyester elastomer, polyolefin elastomer, fluorine elastomer, silicon elastomer, butadiene elastomer, polyamide elastomer, polystyrene elastomer, urethane elastomer , Polyurethane resin, flexible epoxy resin, fluororesin, polycarbonate, polypropylene, polyethylene, polyethylene terephthalate, and polyethylene naphthalate. . The sputtering target according to any one of claims 1 to 10, wherein the synthetic resin is polytetrafluoroethylene. The sputtering target according to any one of claims 1 to 10, wherein the wall thickness of the protective cover is 2.0 mm or more. The sputtering target according to any one of claims 1 to 10, wherein the wall thickness of the protective cover is 5.0 mm or less. The sputtering target according to any one of claims 1 to 10, wherein the Young's modulus of the protective cover is 2000 MPa or less. The sputtering target according to any one of claims 1 to 10, wherein the cylindrical sputtering target contains one selected from the group consisting of ITO, ZnO, IZO, and IGZO as its main component. The sputtering target according to any one of claims 1 to 10, wherein a plurality of the cylindrical sputtering targets are arranged coaxially. A sputtering target packaging method for packaging the sputtering target according to any one of claims 1 to 17, comprising: adjusting the inside of a hollow portion of the cylindrical backing tube to an inert gas environment or a The step of vacuum environment; and the step of forming a protective film so as to cover the openings at both ends of the cylindrical backing tube and seal the inside of the hollow portion. The method of packaging a sputtering target according to claim 18, wherein the pressure of the inert gas inside the hollow portion is 30 kPa to 60 kPa. The method for packaging a sputtering target according to claim 18, wherein the inert gas is argon or nitrogen. The method of packaging a sputtering target according to any one of claims 18 to 20, wherein a dew point temperature of the inert gas inside the hollow portion is -80°C to -50°C.

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