TW201350459A - Ceramic cylindrical sputtering target and method for manufacturing thereof - Google Patents

Abstract

The present invention provides a ceramic cylindrical sputtering target, which is characterized by having a length of 500 mm or more and a relative density of 95% or more, and being formed as an integrated target. By using the ceramic cylindrical sputtering target of the present invention, it is not necessary to use a plurality of overlapped sputtering targets to form a long strip, because the target of the present invention is an integrated target with a high density and having a length of 500 mm or more. Accordingly, when using the ceramic cylindrical sputtering target of the present invention in a device such as a magnetron rotating cathode sputtering device, arcing or particles generation becomes less during sputtering, because there is no divisional part or the number of divisional part is small in the overall target.

Description

Ceramic cylindrical sputtering target and manufacturing method thereof

The present invention relates to a ceramic cylindrical sputtering target and a method of manufacturing the same, and more particularly to a high-density and elongated ceramic cylindrical sputtering target and a method of manufacturing the same.

A magnetron-type rotating cathode sputtering device is a device having a magnetic field generating device inside a cylindrical target and rotating the target to perform sputtering while cooling from the inside of the target to make the target The abrasion is performed comprehensively and the cutting is performed uniformly. Therefore, the use efficiency of the flat type magnetron sputtering apparatus is 20 to 30%, whereas in the magnetron type rotary cathode sputtering apparatus, an extremely high use efficiency of 60% or more can be obtained. Further, by rotating the target, a larger power can be input per unit area than in the conventional flat type magnetron sputtering apparatus, so that a high film formation speed can be obtained.

In recent years, glass substrates used in flat displays and solar cells have been gradually enlarged, and in order to form a film on the enlarged substrate, it is necessary to use a long cylindrical target having a length of more than 3 m.

Such a rotating cathode sputtering method is widely used in metal targets that are easily processed into a cylindrical shape and have high mechanical strength. However, ceramic targets, due to the It is low in strength and brittle, and is prone to cracking or deformation during manufacture. Therefore, in the ceramic target, a short cylindrical cylindrical target can be produced, but a long cylindrical cylindrical target having high performance cannot be produced.

Patent Document 1 discloses a long cylindrical target produced by laminating a short cylindrical cylindrical target, and each target is joined on the basis of the outer peripheral surface of the cylindrical target, and The technique of controlling the arcing or the generation of particles caused by the step is suppressed by controlling the step generated by the divided portion of the target to be 0.5 mm or less. However, in this technique, when the cylindrical target is short, if a plurality of targets are not overlapped, a long cylindrical target cannot be obtained, and thus the divided portion between the target and the target is generated. The number has increased. If the dividing portion is present, even if the step is eliminated, the occurrence of arc discharge caused by the dividing portion cannot be avoided. Therefore, in the aforementioned technique in which the number of divided portions is generated, the number of occurrences of arc discharge increases. Further, since the discharge is concentrated on the divided portion at the time of sputtering, when the number of the divided portions is large, it is easy to cause cracking from the divided portion as a starting point at the time of sputtering. It also takes time to join a plurality of targets, and the manufacturing efficiency is also poor.

In the calcination of a hollow cylindrical ceramic sintered body, the above-described ceramic molding is carried out on a plate-shaped ceramic molded body having a sintering shrinkage ratio equivalent to the sintering shrinkage ratio of the ceramic formed body. The body is calcined to prevent cracking during calcination, and a technique of obtaining a sintered body having a relative density of 95% or more is obtained. However, in this technique, when the ceramic powder is formed, degreased, and sintered to produce a long cylindrical ceramic sintered body having a length of 500 mm or more, in any of the steps of forming, degreasing, and calcining, There is a problem of cracking.

Patent Document 3 discloses a technique of producing an ITO cylindrical target having a length of 500 mm or more by a spray method. However, by the spray method The cylindrical target cannot increase the relative density, and the relative density can only reach 70%. When sputtering is performed using a target having a relatively low density, the number of occurrences of arc discharge increases. Therefore, when sputtering is performed using a long cylindrical target obtained by a spray method, the number of occurrences of arc discharge increases.

Prior technical literature Patent literature

Patent Document 1: Japanese Laid-Open Patent Publication No. 2010-100930

Patent Document 2: Japanese Laid-Open Patent Publication No. 2005-281862

Patent Document 3: Japanese Patent Laid-Open No. Hei 10-68072

It is an object of the present invention to provide a high density and elongated strip of ceramic cylindrical sputtering target.

The present inventors have found a method for producing a ceramic cylindrical sputtering target which does not cause cracking or deformation at the time of manufacture even if the molded body is elongated, and successfully produces a high density and long strip. Ceramic cylindrical splash target.

That is, the present invention is a ceramic cylindrical sputtering target in which the length is 500 mm or more and the relative density is 95% or more, and is an integrated target.

The ceramic cylindrical sputtering target preferably has a length of 750 mm or more, 1000 mm or more, and 1500 mm or more.

The ceramic cylindrical sputtering target material may be, for example, an ITO product in which the content of Sn is 1 to 10% by mass in terms of the amount of SnO ₂ , and the A content of Al is 0.1 to 5% by mass in terms of the amount of Al ₂ O ₃ . The content of In or the content of In is 40 to 60% by mass in terms of the amount of In ₂ O ₃ , the content of Ga is 20 to 40% by mass in terms of the amount of Ga ₂ O ₃ , and the content of Zn is 10 to 30 in terms of the amount of ZnO. IGZO manufacturer of mass %.

Further, the present invention is a ceramic cylindrical sputtering target characterized in that the ceramic cylindrical sputtering target is joined to a backing tube by a bonding material.

Further, the present invention provides a method for producing a ceramic cylindrical sputtering target, which comprises the steps of: preparing a pellet from a slurry containing a ceramic raw material powder and an organic additive, and forming the pellet CIP. Step 2 of the cylindrical shaped body, step 3 of degreasing the formed body, and step 4 of calcining the formed body after degreasing, wherein in the first step 1, the amount of the organic additive is relative to the ceramic The amount of the raw material powder is from 0.1 to 1.2% by mass.

In the method for producing a ceramic cylindrical sputtering target, it is preferable that the organic additive contains a binder which is a polyvinyl alcohol having a degree of polymerization of 200 to 400 and a degree of saponification of 60 to 80 mol% ( Polyvinyl alcohol).

Since the ceramic cylindrical sputtering target of the present invention is an integrated target having a length of 500 mm or more, it is not necessary to overlap a plurality of sputtering targets to form an elongated shape. Therefore, when the ceramic cylindrical sputtering target of the present invention is used in a magnetron rotating cathode sputtering apparatus or the like, since the entire portion of the target does not have a division portion or the number of the division portions is small, sputtering is performed. There are fewer cases of arcing or particles. Further, since the ceramic cylindrical sputtering target of the present invention has a high density, arc discharge is less likely to occur during sputtering.

The method for producing the ceramic cylindrical sputtering target of the present invention can The above-described ceramic cylindrical sputtering target can be efficiently produced by cracking or deformation.

<ceramic cylindrical sputtering target>

The ceramic cylindrical sputtering target of the present invention has a length of 500 mm or more and a relative density of 95% or more, and is an integrated target. The so-called integrated target is not composed of a plurality of parts, but an object in which the entire object is inseparable from the object. It is not an integrated target to overlap a plurality of target parts or to form a target formed by bonding. Therefore, the ceramic cylindrical sputtering target of the present invention is different from a plurality of cylindrical targets or a cylindrical target having a length of 500 mm or more formed by joining.

The ceramic cylindrical sputtering target of the present invention can be produced, for example, by a production method described later.

As described above, since the ceramic target is low in strength and brittle, in the prior sintering method, cracking or deformation is easily generated in the production, and it is impossible to manufacture a ceramic cylindrical splash of an integrated target having a length of 500 mm or more. Plating target. Therefore, in the past, it has been necessary to connect a plurality of short strip-shaped cylindrical sputtering targets having a length of less than 500 mm to form a long cylindrical sputtering target. According to this configuration, the number of divided portions generated between the target and the target increases. Therefore, when sputtering is performed using the target having the above configuration, the number of occurrences of arc discharge caused by the divided portion increases.

Since the ceramic cylindrical sputtering target of the present invention is an elongated body having a length of 500 mm or more, it is not necessary to connect a plurality of targets to constitute a long body. Long strips. In the ceramic cylindrical sputtering target of the present invention, only one of the ceramics can be sputtered or a plurality of sputters can be used depending on the length necessary. When only one of the sputtering is used, since the divided portion does not exist, the arc discharge caused by the divided portion does not occur. Even if a large number of sputterings are connected, since the cylindrical sputtering target constituting this has a length of 500 mm or more, the target length can be constituted by a small number. Therefore, compared with the case where a plurality of short strip-shaped targets are connected to form a long cylindrical sputtering target, the number of divided portions is small, and the number of arc discharges caused by the divided portions is generated. less.

In the conventional spraying method, a long cylindrical ceramic sputtering target having a length of 500 mm or more can be manufactured, but the cylindrical sputtering target obtained by the welding method is relatively The higher density is only 70%. Therefore, when sputtering is performed using a cylindrical sputtering target obtained by a sputtering method, the number of occurrences of arc discharge increases. Since the ceramic cylindrical sputtering target of the present invention has a relative density of 95% or more, the number of arc discharges generated during sputtering is less than that of the cylindrical sputtering target obtained by the sputtering method. .

The ceramic cylindrical sputtering target of the present invention has a length of 500 mm or more, preferably 750 mm or more, particularly preferably 1000 mm or more, and more preferably 1500 mm or more. When one target of the present invention is used for sputtering, the longer the target is, the larger the film formation can be performed, and the arc discharge caused by the divided portion does not occur. When a plurality of targets of the present invention are connected to perform sputtering, the longer the target is, the smaller the target length can be formed, and the number of divided portions can be reduced, so that the cause of the division can be reduced. The number of times the arc discharge is generated.

The upper limit of the length of the ceramic cylindrical sputtering target of the present invention is not particularly limited, and is about 3,400 mm from the viewpoint of the limitation of the magnetron rotating cathode sputtering apparatus.

The ceramic cylindrical sputtering target of the present invention preferably has an inner diameter of 100 mm or more. In the case of the aforementioned inner diameter, film formation can be more efficiently performed by a rotary cathode sputtering method.

The roundness, the cylindricality and the deflection tolerance of the ceramic cylindrical sputtering target of the present invention are preferably within 1 mm, more preferably within 0.5 mm, and even more preferably within 0.1 mm. The smaller the roundness, the cylinder and the deflection tolerance, the more difficult it is to generate an arc discharge, so it is preferable.

The ceramic cylindrical sputtering target of the present invention has a relative density of 95% or more, preferably 99% or more, and particularly preferably 99.5% or more. The higher the relative density of the target, the more the target material can be prevented from being broken by thermal shock or temperature difference during sputtering, and the thickness of the target can be effectively utilized without wasting. In addition, the generation of particles and arc discharge can be reduced, and a good film quality can be obtained. The upper limit of the aforementioned relative density is not particularly limited and is usually 100%.

The type of ceramic of the material of the ceramic cylindrical sputtering target of the present invention is not particularly limited, and examples thereof include an indium oxide-tin oxide-based material (ITO), an alumina-zinc oxide-based material (AZO), and oxidation. Indium-gallium oxide-zinc oxide-based material (IGZO) or the like.

When the ceramic is ITO, the content of Sn in the target is preferably from 1 to 10% by mass, particularly preferably from 2 to 10% by mass, and more preferably from 3 to 10% by mass, in terms of the amount of SnO ₂ . When the content of Sn is within the above range, there is an advantage that the target has a low electrical resistance.

When the ceramic is AZO, the content of Al in the target is preferably from 0.1 to 5% by mass, particularly preferably from 1 to 5% by mass, more preferably from 2 to 5% by mass, in terms of the amount of Al ₂ O ₃ . When the content of Al is within the above range, there is an advantage that the target has a low electrical resistance.

When the ceramic is IGZO, it is preferable that the content of In in the target is 40 to 60% by mass in terms of the amount of In ₂ O ₃ , and the content of Ga is 20 to 50% by mass in terms of the amount of Ga ₂ O ₃ . , Zn in an amount in terms of the content of ZnO is 5 to 30% by mass, and particularly preferably to those, in the content of in ₂ O ₃ in terms of an amount of 40 to 55% by mass, the content of Ga ₂ O ₃ to 25 in terms of the amount of Ga The content of 3% by mass of Zn is 15 to 30% by mass in terms of the amount of ZnO, and more preferably, the content of In is 40 to 50% by mass in terms of the amount of In ₂ O ₃ , and the content of Ga is converted in terms of Ga ₂ O ₃ amount. It is 25 to 35 mass%, and the content of Zn is 20 to 30 mass% in terms of the amount of ZnO. When the content of In, Ga, and Zn is within the above range, there is an advantage that a good TFT (Thin Film Transistor) property can be obtained by sputtering.

<Ceramic cylindrical sputtering target>

The ceramic cylindrical sputtering target of the present invention is obtained by bonding the ceramic cylindrical sputtering target to a support tube by a bonding material.

The aforementioned support tube usually has a cylindrical shape in which a ceramic cylindrical sputtering target can be joined. The type of the support tube is not particularly limited, and can be appropriately selected from conventional support tubes used in accordance with the target. For example, stainless steel, titanium, or the like can be cited as a material for the support tube.

The type of the bonding material is not particularly limited, and can be appropriately selected from conventional bonding materials depending on the target. For example, a solder made of indium or the like can be cited as a bonding material.

The ceramic cylindrical sputtering target can be joined to the outside of one support tube or two or more on the same axis. When two or more are arranged to be joined, the gap between the ceramic cylindrical sputtering targets, that is, the length of the divided portion, It is usually 0.05 to 0.5 mm, preferably 0.05 to 0.3 mm, and particularly preferably 0.05 mm. The shorter the length of the divided portion, the less likely the arc discharge is to occur during sputtering, but when it is less than 0.05 mm, the target may collide with each other and break due to thermal expansion during bonding or sputtering.

The joining method is also not particularly limited, and the same method as the conventional ceramic cylindrical sputtering target can be employed.

<Method of Manufacturing Ceramic Cylindrical Sputtering Target>

The method for producing a ceramic cylindrical sputtering target according to the present invention comprises the steps of: preparing a pellet from a slurry containing a ceramic raw material powder and an organic additive, and shaping the pellet CIP to form a cylindrical shaped body. Step 2, a step 3 of degreasing the formed body, and a method for producing a ceramic cylindrical sputtering target in the step 4 of calcining the formed body after degreasing, wherein the amount of the organic additive in the step 1 is The amount of the ceramic raw material powder is from 0.1 to 1% by mass.

According to this manufacturing method, the ceramic cylindrical sputtering target of the present invention can be efficiently produced without causing cracking or deformation.

In the production method, it is preferable that the organic additive contains a binder which is a polyvinyl alcohol having a polymerization degree of 200 to 400 and a degree of saponification of 60 to 80 mol%.

(step 1)

In the step 1, the particles are prepared from a slurry containing a ceramic raw material powder and an organic additive.

The pellets are prepared from the ceramic raw material powder and the organic additive, and the pellets are supplied to the CIP molding of the step 2, whereby the filling property of the raw material can be improved, and a high-density molded body can be obtained. In addition, it is not easy to produce uneven filling, which can form a uniform charge. fill. It is also not easy to produce uneven molding.

The ceramic raw material powder is a ceramic powder which can be used as a constituent material of the target by the production method.

For example, when the ceramic is ITO, a mixed powder of In ₂ O ₃ powder and SnO ₂ powder may be used as the ceramic raw material powder, or ITO powder may be used alone or in combination with In ₂ O ₃ powder and SnO ₂ powder. The In ₂ O ₃ powder, the SnO ₂ powder, and the ITO powder have a specific surface area as measured by a BET (Brunauer-Emmett-Teller) method, and are usually 1 to 40 m ² /g, respectively. The mixing ratio of the In ₂ O ₃ powder, the SnO ₂ powder, and the ITO powder is appropriately determined so that the content of the constituent elements in the target is within the above range. In the production method, when a mixed powder of In ₂ O ₃ powder and SnO ₂ powder is used as the ceramic raw material powder, the content (% by mass) of the SnO ₂ powder in the ceramic raw material powder is confirmed, and the finally obtained target material can be obtained. The content (% by mass) of Sn converted in terms of the amount of SnO ₂ is considered to be the same.

When the ceramic is AZO, a mixed powder of Al ₂ O ₃ powder and ZnO powder may be used as the ceramic raw material powder, or AZO powder may be used alone or in combination with Al ₂ O ₃ powder and ZnO powder. The specific surface area of the Al ₂ O ₃ powder, the ZnO powder, and the AZO powder measured by the BET method is usually 1 to 40 m ² /g, respectively. The mixing ratio of the Al ₂ O ₃ powder, the ZnO powder, and the AZO powder is appropriately determined so that the content of the constituent elements in the target is within the above range. In the production method, when a mixed powder of Al ₂ O ₃ powder and ZnO powder is used as the ceramic raw material powder, the content (% by mass) of the Al ₂ O ₃ powder in the ceramic raw material powder is confirmed, and the final target can be obtained. The content (% by mass) of Al in terms of the amount of Al ₂ O ₃ in the material was considered to be the same.

When the ceramic is IGZO, a mixed powder of In ₂ O ₃ powder, Ga ₂ O ₃ powder, and ZnO powder may be used as the ceramic raw material powder, or IGZO powder or In ₂ O ₃ powder, Ga ₂ O ₃ powder and ZnO powder is used in combination. The specific surface area of the In ₂ O ₃ powder, the Ga ₂ O ₃ powder, the ZnO powder, and the IGZO powder measured by the BET method is usually 1 to 40 m ² /g, respectively. The mixing ratio of the In ₂ O ₃ powder, the Ga ₂ O ₃ powder, the ZnO powder, and the IGZO powder is appropriately determined so that the content of the constituent elements in the target is within the above range. In the production method, when a mixed powder of In ₂ O ₃ powder, Ga ₂ O ₃ powder, and ZnO powder is used as the ceramic raw material powder, In ₂ O ₃ powder, Ga ₂ O ₃ powder, and the ceramic raw material powder are confirmed. The content (% by mass) of the ZnO powder, the content of In (% by mass) in terms of the amount of In ₂ O ₃ in the finally obtained target, and the content of Ga (% by mass) in terms of the amount of Ga ₂ O ₃ The content (% by mass) of Zn in terms of the amount of ZnO is considered to be the same.

When a ceramic raw material powder obtained by mixing two or more kinds of powders having different particle diameters is used, since the particles of the powder having a small particle diameter enter between the particles of the powder having a large particle diameter, the density of the molded body is high. It also increases the strength of the sintered body.

The mixing method of the powder is not particularly limited. For example, each powder and zirconia ball can be placed in a crucible and ball milled.

The organic additive is a substance which is preferably added to adjust the properties of the slurry or the molded body. Examples of the organic additive include a binder, a dispersant, and a plasticizer.

In the step 1, the amount of the organic additive is from 0.1 to 1.2% by mass, preferably from 0.2 to 1.0% by mass, particularly preferably from 0.4 to 0.8% by mass, based on the amount of the ceramic raw material powder. When the aforementioned compounding amount of the organic additive is more than 1.2% by mass, the strength of the formed body at the time of the dissociation may be greatly lowered, and the degreasing breakage is likely to occur. After cracking, or after degreasing, the number of voids in the formed body increases, and it is difficult to form a high density. When the aforementioned compounding amount of the organic additive is less than 0.1% by mass, a sufficient effect of each component may not be obtained. When the compounding amount of the organic additive is within the above range, a ceramic cylindrical sputtering target having a length of 500 mm or more and a relative density of 95% or more and an integrated target can be produced.

The binder is used to bond the ceramic raw material powder in the formed body to increase the strength of the formed body. The binder can be used for a binder which is usually used in the production of a shaped body in a powder sintering method generally known.

Among them, polyvinyl alcohol (PVA) is preferred, and polyvinyl alcohol having a degree of polymerization of 200 to 400 and a degree of saponification of 60 to 80 mol% is more preferred. When such a binder is used, even if the amount of the binder added is small, particles which are easily pulverized during CIP molding can be prepared, and a molded body which can be closely filled with the ceramic raw material powder by CIP molding and which is not easily broken can be obtained. A ceramic cylindrical target having a high density and a long strip shape can be produced without causing cracking or deformation. For example, when the amount of the organic additive is within the above range, and further using the above-mentioned binder, a ceramic cylinder having a length of 750 mm or more and a relative density of 95% or more and an integrated target can be stably produced. Shape target.

In general, when a long cylindrical ceramic cylindrical target is to be produced by a step of forming, degreasing, and calcining a ceramic powder, it may be produced in any of the steps of forming, degreasing, and calcining. rupture. Therefore, in the conventional production method, a ceramic cylindrical sputtering target having a length of 500 mm or more and a relative density of 95% or more and an integrated target cannot be produced. The crack at the time of molding is considered to be caused by a large elastic force when the CIP molded body is formed into a long shape, that is, when it is formed in a large shape. In the case of casting a shaped body, it is considered to be uneven or granulated with moisture. Sub-segregation is the starting point and a crack occurs. If the amount of the binder is increased, the forming crack can be eliminated, but when the amount of the binder is increased, the cylindrical formed body is brittle and cracked at the time of degreasing or sintering. In addition, excessive addition of the binder causes the binder to segregate and becomes the starting point of the degreasing crack, which is not preferable.

In the production method of the present invention, by using the above-mentioned binder, a long-sized molded body can be obtained by adding a small amount of a binder, thereby obtaining a molded body which is not easily broken. Therefore, in the degreasing and calcining, the round The formed body is not easily broken. That is, when the above-mentioned binder is used, cracking is less likely to occur in any of the steps of forming, degreasing, and calcining, and a long cylindrical ceramic target can be stably obtained.

The reason why the above effects can be obtained by the use of the above-mentioned binder can be considered for the following reasons.

For example, when the granules are prepared by spray-drying a slurry containing a raw material powder, a binder, and water, in the droplets formed by the slurry spray, water is moved to the outside of the droplets by drying, and the raw materials are moved. The powder and binder also move toward the outside of the droplet. The water is volatilized outside the droplets, and as a result, the raw material powder and the binder are tightly aggregated on the surface portion of the droplet to form particles having a hard coating. Since the raw material powder, the binder, and the water move toward the outer peripheral portion, the particles are hollow, and the hollow portion becomes a negative pressure. In order to eliminate the pressure difference, the particles will sag. Since the depressed particles are hard, they are not easily pulverized during forming. Therefore, the formed body cannot be compacted, and a large defect which becomes a starting point of cracking is generated. This is considered to be a major factor in the occurrence of cracks in the production of long strip-shaped formed bodies.

When a binder having a polymerization degree of 200 to 400 is used, the polymer of the component of the binder is less entangled, and a slurry having a low viscosity can be obtained. When the adhesive ratio is set to be constant and a binder having a low degree of polymerization is used, a low viscosity can be produced and A slurry having a high concentration of the raw material powder. Therefore, at the time of spraying of the slurry, since the movement of water in the droplets is small, it is difficult to form a hollow inside the particles and it is not easy to be recessed. In the granules, since the entanglement of the binder is small, the binding force of the binder is weak, and the granules can be simply pulverized. Further, when the high-concentration slurry is sprayed, since the raw material powder and the binder cannot be aggregated on the surface portion of the droplet, the surface portion is less likely to be tight, and the strength of the particles is lowered. For this reason, it can be considered that a molded body in which the ceramic raw material powder is closely packed by CIP molding and is not easily broken can be obtained.

Further, when a binder having a low degree of saponification having a degree of saponification of 60 to 80 mol% is used, in the slurry composed of the raw material powder, the binder, and water, the hydrophobic group of the binder is adsorbed to the powder, and a highly dispersible slurry can be obtained. . When the slurry is sprayed at a temperature above the fog point, the binder is precipitated in a short time without moving to the outside of the droplet, so that the binder can be uniformly dispersed in the entire state of the particles to obtain a surface. Part of the low strength particles. For this reason, it can be considered that a molded body in which the ceramic raw material powder is tightly packed by CIP molding and is not easily broken can be obtained.

As described above, the degree of polymerization and the degree of saponification of the polyvinyl alcohol of the binder are small, and particles which are easily pulverized can be obtained. Therefore, the degree of polymerization of the polyvinyl alcohol of the binder is preferably 400 or less, and the degree of saponification is preferably 80 mol% or less. On the other hand, when the degree of polymerization and the degree of saponification are too small, the obtained molded body becomes too soft, and the handleability is lowered. Therefore, the degree of polymerization of the polyvinyl alcohol of the binder is preferably 200 or more, and the degree of saponification is preferably 60 mol% or more. The polyvinyl alcohol of the binder preferably has a degree of polymerization of from 250 to 350, a degree of saponification of from 65 to 75 mol%, more preferably a degree of polymerization of from 280 to 320, and a degree of saponification of from 68 to 72 mol%.

The amount of polyvinyl alcohol added to the binder relative to the ceramic raw material powder It is preferably from 0.1 to 1.0% by mass, particularly preferably from 0.1 to 0.65% by mass, still more preferably from 0.1 to 0.3% by mass. The more the amount of polyvinyl alcohol added, the higher the plasticity and the less the formation rupture, but on the other hand, the strength of the formed body at the time of de-mediation is greatly reduced, and it is easy to cause degreasing cracking, or after the degreasing, the void in the formed body The number of holes increases, and it is difficult to form a high density. Therefore, it is preferred to be within the aforementioned range.

The dispersant is added to increase the dispersibility of the raw material powder and the binder in the slurry. Examples of the dispersant include ammonium polybasic acid and ammonium polyacrylate.

A plasticizer is added to increase the plasticity of the formed body. Examples of the plasticizer include polyethylene glycol (PRG), ethylene glycol (EG), and the like.

The dispersion medium to be used in the preparation of the slurry containing the ceramic raw material powder and the organic additive is not particularly limited, and may be appropriately selected from water, alcohol, etc. depending on the purpose.

The method of preparing the slurry containing the ceramic raw material powder and the organic additive is not particularly limited, and for example, a method of placing the ceramic raw material powder, the organic additive, and the dispersion medium in a crucible and performing ball milling can be used.

The method of preparing the particles from the slurry is not particularly limited, and for example, a spray drying method, a rotary granulation method, an extrusion granulation method, or the like can be used. Among these, from the viewpoint of high fluidity of the particles and easy production of particles which are easily pulverized during molding, a spray drying method is preferred. The conditions of the spray drying method are not particularly limited, and can be suitably carried out by selecting conditions generally used in the granulation of the ceramic raw material powder.

(Step 2)

In the step 2, the pellet CIP prepared in the step 1 was molded (Cold Isostatic Pressing) to prepare a cylindrical molded body. when When a molded body is produced by CIP molding, a long cylindrical shape molded body which is uniform in density and small in directivity and which is not easily broken by degreasing and calcination can be obtained.

For the mold used for CIP molding, a mold which can be used for CIP molding to form a long cylindrical body, for example, a lid which can seal the upper and lower sides and a cylindrical heart shape (core rod) can be used. A cylindrical amine ester rubber mold or the like.

The pressure at the time of CIP molding is usually 800 kgf/cm ² or more, preferably 1000 kgf/cm ² or more, and more preferably 3000 kgf/cm ² or more. The higher the pressure, the more closely the particles can be filled, and the molded body can be formed into a high density and a high strength. The upper limit of the pressure at the time of CIP molding is not particularly limited, but is usually 5000 kgf/cm ² .

CIP molding, when reduced to a pressurized at a pressure in the range of ² or less of 200kgf / cm, the reduced speed to the preferred 200kgf / cm ^2. Below h, it is particularly preferable to set it to 100 kgf/cm ² . Below h, it is more preferably set to 50 kgf/cm ² . h below. In the pressure reduction in the pressure range of 200 kgf/cm ² or less, the molded body is likely to be broken due to the strong springback force generated by the molded body. When the decompression speed was set to 200 kgf/cm ² . When h is below, the rebound force can be weakened, so that the formed body is not easily broken. When the pressure is reduced at this reduced pressure rate, a ceramic cylindrical target having a high density and a long strip shape can be stably produced. For example, when the binder is used, the blending amount of the organic additive is within the above range, and when the pressure reducing speed is further employed, the length of 1000 mm or more and the relative density of 95% or more can be stably produced, and integrated. A ceramic cylindrical target for a target. The lower limit of the decompression speed is not particularly limited, and is usually 30 kgf/cm ² .

The pressure reduction speed in the range of the pressure higher than 200 kgf/cm ² is not particularly limited, and is usually 200 to 1000 kgf/cm ² . h.

(Step 3)

In the step 3, the formed body produced in the step 2 is degreased. Degreasing is carried out by heating the molded body.

The degreasing temperature is usually from 600 to 800 ° C, preferably from 700 to 800 ° C, particularly preferably from 750 to 800 ° C. The higher the degreasing temperature, the higher the strength of the molded body. However, when it exceeds 800 ° C, the shrinkage of the molded body is caused. Therefore, it is preferred to carry out degreasing at 800 ° C or lower.

The degreasing time is usually from 3 to 10 hours, preferably from 5 to 10 hours, and particularly preferably from 10 hours. The longer the degreasing time, the higher the strength of the molded body, but the degreasing is substantially completed when heated for 10 hours, and the strength of the molded body is not improved even if the extended degreasing time is longer.

The temperature increase rate is preferably 50 ° C / h or less, more preferably 30 ° C / h or less, and still more preferably 20 ° C / h or less in the temperature range of 400 ° C. When the medium is removed before 400 ° C and the temperature is raised at a high speed in the medium, the molded body is easily broken. Therefore, it is preferred to raise the temperature at a low speed of 50 ° C / h or less at 400 ° C. When the temperature increase rate is set to the above range, a ceramic cylindrical target having a high density and a long strip shape can be stably produced. For example, when the amount of the organic additive to be added is within the above range, and the pressure reduction rate during CIP molding is within the above range, and the temperature increase rate at the time of degreasing is within the above range, A ceramic cylindrical target having a length of 1500 mm or more and a relative density of 95% or more and an integral target is stably produced. In a temperature higher than 400 ° C, since the lead time can be shortened by removing the medium, the temperature can be raised at a higher height, for example, about 80 ° C / h.

(Step 4)

In the step 4, the formed body which has been degreased in the step 3 is calcined.

The calcining furnace is not particularly limited, and a calcining furnace used in the production of a conventional ceramic target can be used.

The calcination temperature, when the ceramic is ITO, is usually from 1,450 to 1,700 ° C, preferably from 1,500 to 1,650 ° C, particularly preferably from 1,550 to 1,600 ° C. When the ceramic is AZO or IGZO, it is usually 1250 to 1500 ° C, preferably 1300 to 1450 ° C, and particularly preferably 1350 to 1400 ° C. The higher the calcination temperature, the higher the target can be obtained, but when it is too high, the sintered structure of the target becomes fat and easily broken.

The calcination time is usually from 3 to 30 hours, preferably from 5 to 10 hours, particularly preferably from 5 to 8 hours. The longer the calcination time, the easier the target becomes to be denser, but when it is too long, the sintered structure of the target becomes fat and easily broken.

The rate of temperature rise is usually from 100 to 500 ° C / h. The cooling rate is usually from 10 to 100 ° C / h, preferably from 10 to 50 ° C / h, particularly preferably from 10 to 30 ° C / h. The smaller the cooling rate, the less likely it is to cause cracking due to thermal stress difference, but at less than 10 °C / h, the thermal stress difference usually does not change.

The calcined ambient gas is not particularly limited, and is usually an atmospheric environment or an oxygen atmosphere.

The obtained sintered body can be used as a sputtering target by performing necessary processing such as cutting.

Example

The evaluation methods of the sputtering targets obtained in the examples and the comparative examples are as follows.

Relative density

The relative density of the sputter target is determined according to the Archimedes method. Specifically, the theoretical density ρ (g/cm) is obtained according to the following formula (X) by dividing the volume (= the weight of water in the sintered body of the sputtering target/the specific gravity of water in the measured temperature) by the weight of the air in the sputtering target. ³ ), and the value relative to the theoretical density as the relative density (unit: %).

(In the formula (X), C ₁ to C _i respectively represent the content (% by weight) of the constituent material of the target, and ρ ₁ to ρ _i represent the density (g/cm ³ ₎ of each constituent substance corresponding to C ₁ to C _i . ).

2. Evaluation of cracking of a sputter target or formed body

The sputtering target and the molded body were visually observed, and when the sputtering target or the molded body was not observed to be broken, it was evaluated as "A", and when the crack was observed, it was evaluated as "B".

<ITO target> [Example 1]

So that the content of SnO ₂ powder becomes 1% by mass of the embodiment, the formulation the specific surface area determined the by the BET method is 10m ² / g of SnO ₂ powder, and measured the specific surface area by the BET method is 10m ² / g of In ₂ O ₃ powder, ball-milled by zircon balls in a crucible to prepare a ceramic raw material powder.

In the crucible, 0.1% by mass of polyvinyl alcohol (degree of polymerization: 280, degree of saponification 68 mol) was added as a binder to the ceramic raw material powder, and 0.3% by mass of ammonium polycarboxylate was added as a dispersing agent to the ceramic raw material powder. And adding 15 mass% of water to a ceramic raw material powder as a dispersion medium, and ball-mixing and mixing to prepare a slurry. The total amount of organic additives (the combination of the amount of polyvinyl alcohol and the amount of ammonium polycarboxylate) The ratio of the amount relative to the amount of the ceramic raw material powder was 0.4% by mass.

The slurry was supplied to a spray drying apparatus, and spray-dried under the conditions of atomization number of revolutions of 10,000 rpm and an inlet temperature of 250 ° C to prepare pellets.

In a urethane-based rubber mold having a cylindrical shape of a core shape (core rod) having an outer diameter of 165 mm and having a cylindrical shape of 210 mm (thickness: 10 mm) and a length of 1,219 mm, After the particle vibration was filled, the rubber mold was sealed, and CIP molding was performed at a pressure of 800 kgf/cm ² to produce a cylindrical molded body. The decompression speed after CIP molding was set to 300 kgf/cm ^{2 in} a pressure range of more than 200 kgf/cm ² . h, in the pressure range of 200 kgf/cm ² or less, it is set to 200 kgf / cm ² . h. The length of the obtained molded body was 1212 mm.

The formed body was heated and degreased. The degreasing temperature was 700 ° C, the degreasing time was 10 hours, the temperature increase rate was 20 ° C / h in the temperature range of 400 ° C, and 50 ° C / h in the temperature range higher than 400 ° C.

The molded body after degreasing is calcined to prepare a sintered body. The calcination was carried out in an air atmosphere, and the calcination temperature was 1600 ° C, the calcination time was 10 hours, the temperature increase rate was 300 ° C / h, and the temperature drop rate was 50 ° C / h.

The obtained sintered body was subjected to a cutting process to produce an ITO cylindrical sputtering target having an outer diameter of 155 mm, an inner diameter of 135 mm, and a length of 1000 mm.

Three of the above-mentioned targets were bonded to a support tube made of SUS304 having an outer diameter of 133 mm, an inner diameter of 123 mm, and a length of 3,200 mm by In solder to prepare an ITO target. The interval between the targets (the length of the divided portion) was set to 0.2 mm.

The evaluation of the relative density of the target and the cracking of the target and the molded body is described in Table 1.

[Examples 2 to 20, Comparative Examples 1 to 9]

Examples 2 to 20 and Comparative Examples 1 to 9 were carried out under the following conditions.

The content of the SnO ₂ powder in the ceramic raw material powder, the degree of polymerization and the degree of saponification of the polyvinyl alcohol, the amount of the polyvinyl alcohol added, and the amount of the polyvalent ammonium carboxylate added are set as shown in Table 1, except The pellets were prepared in the same manner as in Example 1 except that the pellets were prepared.

The pellet was subjected to CIP molding to prepare a cylindrical molded body having a length as shown in Table 1. In the CIP molding, the amine ester rubber molds of the same manner as in the first embodiment were used in the examples 2, 3, 9 to 18, and the comparative example 6, and the other examples and comparative examples were used in the same manner as in the first embodiment. The urethane rubber mold has the same core shape and inner diameter, and has an amine ester rubber mold having a length of a molded body having a length as shown in Table 1. The pressure reduction rate in the pressure range of 200 kgf/cm ² or less after the CIP molding was set as the condition shown in the first table. Other CIP forming conditions other than this were set to be the same as in the first embodiment. In Comparative Example 5, the formed body was cracked in the forming step.

The formed body which did not cause cracking in the forming step was subjected to heat degreasing. The temperature rise temperature in the temperature range of 400 ° C was set to the conditions shown in Table 1, and the other degreasing conditions were the same as in Example 1. In Comparative Examples 1 to 4 and 8 to 9, the formed body was cracked in the degreasing step.

The molded body which did not cause cracking in the degreasing step was calcined under the same conditions as in Example 1 to prepare a sintered body. The obtained sintered body was subjected to a cutting process to produce an ITO cylindrical sputtering target having an outer diameter, an inner diameter, and a length as shown in Table 1.

By obtaining the number of divisions as shown in Table 1, by The In solder was bonded to a support tube made of SUS304 having an outer diameter of 133 mm, an inner diameter of 123 mm, and a length of 3,200 mm by a plurality of (the number of the number of divisions). The target was bonded to an ITO target. The interval between the targets (the length of the divided portion) was set to 0.2 mm.

The evaluation of the relative density of each of the obtained targets and the cracking of the target and the molded body is described in Table 1.

<AZO target> [Example 21]

So the content of Al ₂ O ₃ powder is 0.5% by mass of the embodiment, the formulation the specific surface area determined the by the BET method of 5m ² / g of Al ₂ O ₃ powder, and measured the specific surface area by the BET method is 10m ² / g The ZnO powder was ball-milled by a zirconia ball in a crucible to prepare a ceramic raw material powder.

Granules were prepared in the same manner as in Example 1 except that the ceramic raw material powder was used.

A cylindrical ester-shaped urethane rubber mold having an inner diameter of 213 mm (thickness: 10 mm) and a length of 1233 mm having a cylindrical shape (core rod) having a cylindrical outer diameter of 167 mm and having a lid which can be closed at the upper and lower sides is used. The CIP molding was carried out under the same conditions as in Example 1, and a cylindrical molded body having the length shown in Table 2 was produced.

This molded body was degreased under the same conditions as in Example 1.

The degreased molded body was calcined under the same conditions as in Example 1 to prepare a sintered body. The obtained sintered body was subjected to a cutting process to produce an AZO cylindrical sputtering target having an outer diameter, an inner diameter, and a length as shown in the second table.

Three kinds of the above-mentioned targets were bonded to a support tube made of SUS304 having an outer diameter of 133 mm, an inner diameter of 123 mm, and a length of 3,200 mm by In solder to produce AZO. target. The interval between the targets (the length of the divided portion) was set to 0.2 mm.

The evaluation of the relative density of the target and the cracking of the target and the molded body is shown in Table 2.

[Examples 22 to 33, Comparative Examples 10 to 18]

Examples 22 to 33 and Comparative Examples 10 to 18 were carried out under the following conditions.

The content of the Al ₂ O ₃ powder in the ceramic raw material powder, the degree of polymerization and the degree of saponification of the polyvinyl alcohol, the amount of the polyvinyl alcohol added, and the amount of the polyvalent ammonium carboxylate added are set as shown in the second table. Otherwise, the same procedure as in Example 21 was carried out to prepare pellets.

The pellet was subjected to CIP molding to prepare a cylindrical molded body having a length as shown in Table 2. In the CIP molding, the same examples as in Example 22, 28 to 30, 33, and Comparative Example 14 were used, and the other examples and comparative examples were used. The urethane rubber mold has the same core shape and inner diameter, and has an amine ester rubber mold having a length of a molded body having a length as shown in Table 2. The pressure reduction rate in the pressure range of 200 kgf/cm ² or less after the CIP molding was set as the condition shown in the second table. Other CIP molding conditions other than this were the same as in Example 21. In Comparative Example 13, the molded body was cracked in the forming step.

The formed body which did not cause cracking in the forming step was subjected to heat degreasing. The temperature rise temperature in the temperature range of 400 ° C was set to the conditions shown in Table 2, and other degreasing conditions were the same as in Example 21. In Comparative Examples 10 to 12 and 16 to 18, the formed body was cracked in the degreasing step.

a degreased molded body which does not cause cracking in the degreasing step, The sintered body was produced by calcination under the same conditions as in Example 21. The obtained calcined body was subjected to a cutting process to produce an AZO cylindrical sputtering target having an outer diameter, an inner diameter, and a length as shown in the second table.

In order to obtain the number of divided portions as shown in the second table, a plurality of (the number of the number more than one of the number of divided portions) of the In solder is bonded to the outer diameter of 133 mm and an inner diameter of 123 mm. A support tube made of SUS304 having a length of 3,200 mm was used to produce an AZO target. The interval between the targets (the length of the divided portion) was set to 0.2 mm.

The evaluation of the relative density of each of the obtained targets and the cracking of the target and the molded body is shown in the second table.

<IGZO target> [Example 34]

The specific surface area measured by the BET method was adjusted to 10 m ² / so that the content of the In ₂ O ₃ powder was 44.2% by mass, the content of the Ga ₂ O ₃ powder was 29.9% by mass, and the content of the ZnO powder was 25.9% by mass. g of in ₂ O ₃ powder, a specific surface area measurement of a BET method of ² g of Ga ₂ O ₃ powder was 10m /, and as determined by the BET method, the specific surface area of 10m ² / g of ZnO powder, in the melt tank The ceramic raw material powder was prepared by ball milling mixing with zirconia balls.

The same procedure as in Example 1 was carried out, except that the ceramic raw material powder was used, and polyvinyl alcohol (degree of polymerization: 500, degree of saponification: 90 mol%) was used instead of polyvinyl alcohol (degree of polymerization: 280, degree of saponification: 68 mol%). The particles are prepared.

A urethane rubber mold having a cylindrical shape of a core shape (core rod) having an outer diameter of 171 mm and having a cylindrical shape of 171 mm (thickness: 10 mm) and a length of 653 mm was used, and CIP was used. The pressure reduction rate in the pressure range of 200 kgf/cm ² or less after molding was set to 300 kgf/cm ² . h, except that the pellets were subjected to CIP molding under the same conditions as in Example 1, and a cylindrical molded body having a length as shown in Table 3 was produced.

This molded body was degreased under the same conditions as in Example 1.

The degreased molded body was calcined under the same conditions as in Example 1 to prepare a sintered body. The obtained sintered body was subjected to a cutting process to produce an IGZO cylindrical sputtering target having an outer diameter, an inner diameter, and a length as shown in Table 3.

The IGZO target was produced by bonding six of the above-mentioned targets to a support tube made of SUS304 having an outer diameter of 133 mm, an inner diameter of 123 mm, and a length of 3,200 mm by In solder. The interval between the targets (the length of the divided portion) was set to 0.2 mm.

The evaluation of the relative density of the target and the cracking of the target and the molded body is shown in Table 3.

[Examples 35 to 44, Comparative Examples 19 to 25]

Examples 35 to 44 and Comparative Examples 19 to 25 were carried out under the following conditions.

The content of the In ₂ O ₃ powder in the ceramic raw material powder, the content of the Ga ₂ O ₃ powder, the content of the ZnO powder, the degree of polymerization and the degree of saponification of the polyvinyl alcohol, the addition amount of the polyvinyl alcohol, and the ammonium polycarboxylate. The pellets were prepared in the same manner as in Example 34 except that the amount of addition was set to the conditions shown in Table 3.

The pellet was subjected to CIP molding to prepare a cylindrical molded body having a length as shown in Table 3. In the CIP molding, with respect to Examples 35 to 36, Comparative Examples 19 to 20, and 22 to 25, the same amine ester rubber mold as in Example 34 was used, and with respect to the other examples and comparative examples, the use of Example 34 was carried out. The amine ester rubber mold used has the same core shape and inner diameter, and has an amine ester rubber mold having a length of a molded body having a length as shown in Table 2. The pressure reduction rate in the pressure range of 200 kgf/cm ² or less after the CIP molding was set as the condition shown in the third table. Other CIP forming conditions other than this were set to be the same as in Example 34. In Comparative Example 20, the formed body was cracked in the forming step.

The formed body which did not cause cracking in the forming step was subjected to heat degreasing. The temperature rise temperature in the temperature range of 400 ° C was set to the conditions shown in Table 3, and other degreasing conditions were the same as in Example 34. In Comparative Examples 19 and 23 to 25, the formed body was cracked in the degreasing step.

The molded body which did not cause cracking in the degreasing step was calcined under the same conditions as in Example 34 to prepare a sintered body. The obtained sintered body was subjected to a cutting process to produce an IGZO cylindrical sputtering target having an outer diameter, an inner diameter, and a length as shown in Table 3.

In order to obtain the number of divided portions as shown in the third table, the plurality of (the number of the number more than one of the number of divided portions) of the In solder is bonded to the outer diameter of 133 mm and the inner diameter of 123 mm. An IGZO target was produced by a support tube made of SUS304 having a length of 3000 mm. The interval between the targets (the length of the divided portion) was set to 0.2 mm.

The evaluation of the relative density of each of the obtained targets and the cracking of the target and the molded body is shown in Table 3.

As shown in the first to third tables, in Examples 1 to 44 in which the production method of the present invention is carried out, cracking of the target material and the molded body is not caused during the production of the target, and it is possible to obtain a shape of 500 mm or more. An ITO cylindrical sputter target having a relative density of 95% or more, an AZO cylindrical sputter target, or an IGZO cylindrical sputter target, and thus a target formed.

In the comparative example in which the manufacturing method according to the present invention is carried out, when the amount of the organic additive is more than 1.2% by mass relative to the amount of the ceramic raw material powder, the formed body may be cracked in the degreasing step, or the relative density of the target may be low. At 95%, when the amount of the organic additive is less than 0.1% by mass relative to the amount of the ceramic raw material powder, the formed body may be broken during the forming step. In the comparative example, a ceramic cylindrical sputtering target having a length of 500 mm or more and a relative density of 95% or more could not be produced.

Claims (10)

A ceramic cylindrical sputtering target characterized by a length of 500 mm or more and a relative density of 95% or more, and is an integrated target. The ceramic cylindrical sputtering target according to claim 1, wherein the length is 750 mm or more. The ceramic cylindrical sputtering target according to claim 1, wherein the length is 1000 mm or more. The ceramic cylindrical sputtering target according to claim 1, wherein the length is 1500 mm or more. The ceramic cylindrical sputtering target according to any one of claims 1 to 4, wherein the content of Sn is ITO of 1 to 10% by mass in terms of the amount of SnO ₂ . The ceramic cylindrical sputtering target according to any one of claims 1 to 4, wherein the content of Al is 0.1 to 5% by mass of AZO in terms of the amount of Al ₂ O ₃ . The ceramic cylindrical sputtering target according to any one of claims 1 to 4, wherein the content of the In is 40 to 60% by mass in terms of the amount of In ₂ O ₃ , and the content of Ga is The amount of Ga ₂ O ₃ is 20 to 40% by mass, and the Zn content is 10 to 30% by mass in terms of the amount of ZnO. A ceramic cylindrical sputtering target characterized by bonding a ceramic cylindrical sputtering target according to any one of claims 1 to 7 to a support tube by a bonding material. to make. A method for manufacturing a ceramic cylindrical sputtering target, comprising: a step 1 of preparing a granule from a slurry containing a ceramic raw material powder and an organic additive; a step 2 of subjecting the granule to CIP molding to form a cylindrical shaped body; a step 3 of degreasing the shaped body; and squeezing the defatted In the step (1), the amount of the organic additive is 0.1 to 1.2% by mass based on the amount of the ceramic raw material powder. The method for producing a ceramic cylindrical sputtering target according to claim 9, wherein the organic additive contains a binder, and the binder is a polyethylene having a degree of polymerization of 200 to 400 and a degree of saponification of 60 to 80 mol%. alcohol.