KR102001363B1 - Cylindrical sputtering target and manufacturing method of cylindrical sputtering target - Google Patents

Abstract

A cylindrical sputtering target having a length in the cylindrical axis direction of 470 mm or more, and a manufacturing method thereof. A method of manufacturing a cylindrical sputtering target according to an embodiment of the present invention is a method of manufacturing a cylindrical sputtering target having a cylindrical sintered body, comprising the steps of: forming, on a stage having an oxygen supply port connected to a pipe for supplying oxygen, A cylindrical shaped body having a length of 600 mm or more is placed and sintered while supplying oxygen from the oxygen supply port which is smaller than the inner circumference of the cylinder provided inside the cylinder of the cylindrical formed body in the axial direction of the cylinder. In another aspect, the stage is disposed in the chamber, and the piping for supplying oxygen may be connected to the oxygen supply port from outside the chamber.

Description

TECHNICAL FIELD [0001] The present invention relates to a cylindrical sputtering target and a method of manufacturing the same. BACKGROUND ART < RTI ID = 0.0 >

The present invention relates to a cylindrical sputtering target and a manufacturing method thereof. In particular, the present invention relates to a method of manufacturing a cylindrical sintered body constituting a cylindrical sputtering target.

BACKGROUND ART [0002] In recent years, flat panel displays (FPDs) and manufacturing techniques for solar cells have rapidly developed and are becoming larger. In addition, as this market expands, the demand for large-size glass substrates is increasing.

Particularly, as a sputtering apparatus for forming a metal thin film or a thin metal oxide film on a large glass substrate, a cylindrical (rotary or rotary type) sputtering target is used instead of a conventional flat sputtering target. The cylindrical sputtering target is advantageous in that the efficiency of use of the target is high, generation of erosion is small, and generation of particles due to separation of the deposit is small as compared with the flat sputtering target.

A cylindrical sputtering target used in a sputtering apparatus for forming a thin film on a large glass substrate as described above requires a length of 3000 mm or more. It is not technically realistic to manufacture a cylindrical sputtering target having such a length by integrally forming it and grinding it. Thus, a divided sputtering target is constituted to which a plurality of cylindrical sintered bodies, typically several 10 mm to several hundreds of millimeters, are connected.

Here, not only the cylindrical sintered body but also a general sintered body is required to have improved mechanical strength and to improve the film quality of the thin film using the sintered body. When a plurality of sintered bodies are bonded to a substrate, the sintered bodies are arranged at regular intervals. When the sintered body is arranged without gaps and bonded to the substrate, the sintered body is stretched or shrunk by heat during sputtering and collapses or breaks due to collision between the sintered bodies. On the other hand, a sintered body to be originally sputtered I never do that. Therefore, there is a problem that the constituent material of the substrate is sputtered or the like, and a thin film of a desired composition can not be formed. In a divided sputtering target to which a plurality of sintered bodies are connected, the difference in relative density between adjacent sintered bodies (i.e., "inter-solid heterogeneity" of the sintered body density) affects the quality of the thin film using the divided sputtering target. As described above, the shorter the sintered body to be connected is, the more divided the sputtering target becomes, so that the risk of affecting the sputtering characteristics is increased.

In order to avoid the above problem at least, there is a demand for a technique for manufacturing a longer cylindrical sintered body capable of coping with the division of the sputtering target into small pieces. A problem in the production of a long cylindrical sintered body is the difference in relative density in the sintered body (i.e., "non-uniformity in solid" of the sintered body density) and mechanical strength. For example, in Patent Document 1, it has been disclosed that the sintering of the ITO target significantly affects the quality stabilization (density and strength) of the oxygen concentration in the atmosphere. Generally, in a sintering furnace used for ITO, oxygen is supplied from the furnace wall side.

Patent Document 1: JP-A-8-144056

However, in the case of a long cylindrical sintered body, oxygen deficiency occurs in the cylinder due to insufficient gas convection in the cylinder during sintering. A problem of the present invention is to provide a cylindrical sintered body, a cylindrical sputtering target and a method of manufacturing such a cylindrical sintered body having a length in the axial direction of the cylinder of 470 mm or more since the divided sputtering target obtained by joining a plurality of sintered bodies to a substrate corresponds to small- . It is another object of the present invention to provide a cylindrical sintered body, a cylindrical sputtering target, and a method of manufacturing such a cylindrical sintered body having high homogeneity in a solid body and between individuals.

A method of manufacturing a cylindrical sputtering target according to an embodiment of the present invention is a method of manufacturing a cylindrical sputtering target having a cylindrical sintered body, comprising the steps of: forming, on a stage having an oxygen supply port connected to a pipe for supplying oxygen, A cylindrical shaped body having a length of 600 mm or more is placed and sintered while supplying oxygen from the oxygen supply port which is smaller than the inner circumference of the cylinder provided inside the cylinder of the cylindrical formed body in the axial direction of the cylinder.

In another aspect, the stage is disposed in the chamber, and the piping for supplying oxygen can be connected to the oxygen supply port from outside the chamber.

Further, in another form, oxygen can be sintered while being fed toward the cylindrical hollow inside of the cylindrical formed body.

Further, in another aspect, oxygen can be sintered while supplying oxygen upward from a lower portion in the cylindrical axis direction of the cylindrical formed body.

A cylindrical sintered body used as a cylindrical sputtering target according to an embodiment of the present invention has a relative density difference of 0.1% or less in the cylindrical axis direction in a cylindrical sintered body having a length in the axial direction of the cylinder of 470 mm or more.

A cylindrical sintered body used as a cylindrical sputtering target according to an embodiment of the present invention is a cylindrical sintered body having a length in the axial direction of the cylinder of 470 mm or more and the circle equivalent diameter of the area in the hole observed in the inner side of the cylinder is 1 μm or less to be.

A cylindrical sintered body using a cylindrical sputtering target according to an embodiment of the present invention, in the cylindrical sintered body, the length of the cylinder axial direction at least 470 mm, one can average 4.25 × 10 ^-5 of the hole observed in the inner surface of the cylindrical / μm ² Or less.

In another aspect, the hole observed at the inner side of the cylinder may be a hole observed at least at a distance of 1.176 mm ² at five independent points in the central portion in the cylindrical axis direction.

According to the present invention, it is possible to provide a cylindrical sintered body, a cylindrical sputtering target and a manufacturing method thereof having a length in the axial direction of the cylinder of 470 mm or more. Alternatively, it is possible to provide a cylindrical sintered body, a cylindrical sputtering target, and a method of manufacturing such a cylindrical sintered body having high homogeneity in a solid body and between individuals.

1 is a perspective view showing an example of a cylindrical sintered body constituting a cylindrical sputtering target according to an embodiment of the present invention.
2 is a cross-sectional view showing an example of the configuration of a cylindrical sputtering target after assembly according to one embodiment of the present invention.
3 is a process flow illustrating a method of manufacturing a cylindrical sintered body according to one embodiment of the present invention.
4 is a perspective view showing a step of sintering a cylindrical formed body in a method of manufacturing a cylindrical sintered body according to an embodiment of the present invention.
5 is a cross-sectional view showing a step of sintering a cylindrical formed body in a method of manufacturing a cylindrical sintered body according to an embodiment of the present invention.
6 is a plan view showing a step of sintering a cylindrical formed body in a method of manufacturing a cylindrical sintered body according to an embodiment of the present invention.
7 is a plan view showing a step of sintering a cylindrical formed body in a method of manufacturing a cylindrical sintered body according to a first modified example of the embodiment of the present invention.
8 is a cross-sectional view showing a step of sintering a cylindrical formed body in a method of manufacturing a cylindrical sintered body according to a second modification of the embodiment of the present invention.
9 is a view showing sampling positions of measurement samples in a cylinder axis direction in a cylindrical sintered body related to Examples and Comparative Examples of the present invention.
10 is a table showing density, solid density difference, relative density, and maximum relative density difference in a solid of a cylindrical sintered body according to Examples and Comparative Examples of the present invention.
11 is a diagram showing the relationship between the length of the cylindrical sintered body and the minimum oxygen supply amount in relation to the embodiment and the comparative example of the present invention.
12 is a table showing the bulk resistance and the bulk resistance value difference in solid of the cylindrical sintered body related to the example of the present invention and the comparative example.
13 is a view showing sampling positions of measurement samples on the inner side face and the outer side face of a cylindrical sintered body relating to Examples and Comparative Examples of the present invention.
Fig. 14 is an electron microscope (SEM, 1000 times) photograph of a cylindrical inner surface of a cylindrical sintered body relating to Examples and Comparative Examples of the present invention.
15 is a photograph of an electron microscope (SEM, 1000 times) on the outer surface of a cylinder of a cylindrical sintered body relating to Examples and Comparative Examples of the present invention.
16 is a photograph of an electron microscope (SEM, 5000 times or 2000 times) on the inner surface of a cylinder of a cylindrical sintered body according to the example of the present invention and the comparative example.
17 is a photograph of an electron microscope (SEM, 5000 times) on the outer surface of a cylinder of a cylindrical sintered body relating to Examples and Comparative Examples of the present invention.
Fig. 18 is a table showing the circle-equivalent diameter of an area in a hole on the inner side of a cylinder of a cylindrical sintered body according to one embodiment of the present invention and the comparative example, and the average of numbers.

Hereinafter, a cylindrical sputtering target and a manufacturing method thereof according to the present invention will be described with reference to the drawings. However, the cylindrical sputtering target of the present invention and the manufacturing method thereof can be carried out in many different forms, and are not limited to the description of the embodiments described below. Incidentally, in the drawings referred to in the present embodiment, the same reference numerals are given to the same portions or portions having the same functions, and repeated descriptions thereof are omitted.

<Embodiment>

The outline of the structure and structure of the cylindrical sputtering target and the cylindrical sintered body related to the embodiment of the present invention will be described with reference to Figs. 1 and 2. Fig.

[Outline of Cylindrical Sputtering Target]

1 is a perspective view showing an example of a cylindrical sintered body constituting a cylindrical sputtering target according to an embodiment of the present invention. As shown in Fig. 1, the cylindrical sputtering target 100 has a plurality of cylindrical sintered bodies 110 having a hollow structure. The plurality of cylindrical sintered bodies 110 are arranged adjacent to each other through a certain space. Here, in FIG. 1, for convenience of explanation, the space of adjacent cylindrical sintered bodies 110 is enlarged. 2, a cylindrical base member 130 for holding the cylindrical sintered body 110 is introduced into the cylindrical hollow portion of the cylindrical sintered body 110 in detail.

The thickness of the cylindrical sintered body 110 may be 6.0 mm or more and 20.0 mm or less. The length of the cylindrical sintered body 110 in the axial direction of the cylinder can be 470 mm or more and 1500 mm or less. The outer diameter of the cylindrical sintered body 110 may be 147 mm or more and 175 mm or less. The inner diameter of the cylindrical sintered body 110 may be 135 mm or less. The space in the axial direction of the cylinder between adjacent cylindrical sintered bodies 110 can be 0.1 mm or more and 0.4 mm or less.

Examples of the material of the cylindrical sintered body 110 include indium tin oxide (ITO) composed of indium, tin and oxygen, IZO sintered body made of indium, zinc and oxygen, indium, gallium, zinc IGZO sintered body (Indium Gallium Zinc Oxide) composed of zinc, aluminum and oxygen, and sintered bodies of AZO sintered body, zinc oxide (ZnO) and TiO ₂ . However, the cylindrical sintered body of the cylindrical sputtering target according to the present invention is not limited to the above composition as long as it is a ceramic sintered body containing oxygen.

Here, the density of the cylindrical sintered body 110 in the present embodiment may be 99.5% or more. The density of the cylindrical sintered body 110 may more preferably be not less than 99.6%. Further, the difference in relative density in the cylindrical axis direction in the solid of the cylindrical sintered body 110 may be 0.1% or less. The difference in relative density in the cylindrical axis direction of the cylindrical sintered body 110 may be more preferably 0.05% or less, still more preferably 0.03% or less. The difference in relative density between adjacent cylindrical sintered bodies 110a and 110b, that is, the difference in relative density between solid bodies of the cylindrical sintered body, can be preferably 0.1% or less.

On the other hand, the density of the sintered body is expressed by the relative density. Relative density is represented by relative density = (measured density / theoretical density) x 100 (%) by the measured density and theoretical density. The relative density difference is represented by the relative density difference = (measured density difference / theoretical density) x 100 (%) by the difference in the measured density and the theoretical density. The theoretical density is a density value calculated from the theoretical density of an oxide of an element other than oxygen in each constituent element of the sintered body. For example, in the case of an ITO target, indium (In ₂ O ₃ ) and tin oxide (SnO ₂ ) as oxides of indium and tin excluding oxygen among indium, tin and oxygen, which are constituent elements, . Here, the mass ratio of indium oxide (In ₂ O ₃ ) and tin oxide (SnO ₂ ) is converted from elemental analysis values (at% or mass%) of indium and tin in the sintered body. For example, as a result of conversion, in the case of an ITO target in which indium oxide is 90 mass% and tin oxide is 10 mass%, the theoretical density is (density of In ₂ O ₃ (g / cm ³ ) × 90 + density of SnO ₂ g / cm ³ ) × 10) / 100 (g / cm ³ ). The theoretical density of In ₂ O ₃ is calculated to be 7.18 g / cm ³ , the theoretical density of SnO ₂ is calculated to be 6.95 g / cm ³ , and the theoretical density is calculated to be 7.157 (g / cm ³ ). Further, if each constituent element is Zn, it can be calculated as ZnO, and if it is Ga, it can be calculated as an oxide of Ga ₂ O ₃ . The theoretical density of ZnO is calculated to be 5.67 g / cm ³ and the theoretical density of Ga ₂ O ₃ to be 5.95 g / cm ³ . On the other hand, the measurement density is a value obtained by dividing weight by volume. In the case of the sintered body, the volume is calculated by the Archimedes method and is calculated. The difference in relative density in the cylindrical axial direction of the cylindrical sintered body 110 is obtained by cutting a cylindrical measurement sample having a width of 40 to 50 mm at intervals of 150 mm with respect to the cylindrical axis direction of the cylindrical sintered body 110, Can be evaluated by calculating the relative density.

As described above, by setting the length and the relative density of the cylindrical sintered body within the above-mentioned range, the mechanical strength of the cylindrical sintered body can be improved, and generation of nodules and generation of particles accompanying arcing can be suppressed when the cylindrical sintered body is used The effect of reducing impurities in the thin film and improving the film density can be obtained. Further, by setting the difference in the relative density between the solid and the solid in the cylindrical sintered body within the above ranges, it is possible to suppress the electric field distortion in the divided sputtering target having a plurality of cylindrical sintered bodies. As a result, stable discharge characteristics can be obtained at the time of sputtering, and a thin film having a very high in-plane uniformity of the film quality can be formed on a large substrate exceeding the size of one cylindrical sintered body.

The difference in the solid in the cylindrical sintered body 110 and the difference in the inner and outer cylindrical surfaces of the cylindrical sintered body 110 are also included. The inner and outer side surfaces of the cylindrical sintered body 110 can be evaluated by an electron microscope (SEM) observation. In the present embodiment, a large difference can not be seen in the holes observed in the cylindrical inner side surface and the outer side surface of the cylindrical sintered body 110 at the central portion in the axial direction of the cylinder. The shapes of the holes observed in the inner and outer surfaces of the cylindrical sintered body 110 in this embodiment have an irregular shape and are observed everywhere in the grain boundaries and crystals. In other words, in this embodiment, irregular bubble-like holes are observed in the crystal grain boundaries and in the crystal at the inner and outer side surfaces of the cylindrical sintered body 110. On the other hand, in the cylindrical inner sidewall of the cylindrical sintered body 110 in the comparative example having a length in the axial direction of the cylinder axis of 470 mm or more, the outer surface of the cylinder in the comparative example and the cylindrical outer surface of the cylindrical sintered body 110 in this embodiment Compared to the inner and outer surfaces, a hole with a larger irregular shape is observed. In other words, irregular crystal grain holes are observed on the inner surface of the cylindrical sintered body 110 in the comparative example in which the length in the cylindrical axis direction is 470 mm or more. In this comparative example, the holes observed at the inner side of the cylinder of the cylindrical sintered body 110 are mainly observed at grain boundaries. The cylindrical outer side surface of the cylindrical sintered body 110 in the comparative example can not be greatly different from the inner side surface and the outer side surface of the cylindrical sintered body 110 in the present embodiment. The shape of the hole observed in the cylindrical outer surface of the cylindrical sintered body 110 in the comparative example is small and irregular in shape compared to the hole in the inner surface of the cylindrical cylinder, and is observed everywhere in the grain boundaries and the crystal.

The shapes of the respective holes observed in the cylindrical inner side surface and the cylindrical outer side surface of the cylindrical sintered body 110 in this embodiment and the comparative example are irregular. Therefore, the size of the hole can be evaluated by calculating the area when one continuous hole is viewed from the plane and calculating the diameter of the circle having the corresponding area (hereinafter referred to as circle equivalent diameter of the area in the hole) have. The number of holes may be calculated as one continuous hole in the surface to be observed. In the present embodiment, the average of the circle-equivalent diameters of the areas in the holes observed in the cylindrical inner surface of the cylindrical sintered body 110 may be 1 m or less. The average of the circle-equivalent diameters of the areas in the holes observed in the inner side of the cylinder of the cylindrical sintered body 110 may be more preferably 0.5 m or less. The average number of holes observed in the cylindrical inner surface of the cylindrical sintered body 110 in the present embodiment may be 4.25 占^0-5 pieces / 占 퐉 ² or less. The average number of holes observed in the cylindrical inner surface of the cylindrical sintered body 110 may more preferably be 2.125 x 10 &lt; ^-5 &gt; / m &lt; ² &gt; In addition, the average of the circle-equivalent diameters of the areas in the holes observed in the cylindrical outer surface of the cylindrical sintered body 110 in the present embodiment may be 1 m or less. The average of the circle-equivalent diameters of the areas in the holes observed in the cylindrical outer surface of the cylindrical sintered body 110 may be more preferably 0.5 m or less. The average number of holes observed in the cylindrical outer surface of the cylindrical sintered body 110 in the present embodiment may be 4.25 占^0-5 pieces / 占 퐉 ² or less. The average number of holes observed in the cylindrical outer surface of the cylindrical sintered body 110 may more preferably be 2.125 x 10 &lt; ^-5 &gt; / m &lt; ² &gt;

On the other hand, the cylindrical inner side surface and the outer side surface state of the cylindrical sintered body 110 were evaluated by observing five visual fields of 980 mu m x 1200 mu m in the central portion in the cylindrical axis direction of each sample, The average value of the circle-equivalent diameters of the circle-equivalent diameters is evaluated. The circle equivalent diameter L of the area S in the hole can be obtained by first calculating the projected area S of one continuous hole and calculating the diameter L of the circle having the equivalent area by the following expression.

[Equation 1]

In the present embodiment, a large difference can not be seen in the crystal grains observed on the inner side surface and the outer side surface of the cylindrical sintered body 110 in the cylindrical axial center portion. The crystal grains observed on the inner side surface and the outer side surface of the cylindrical sintered body 110 in the present embodiment are greatly grown. On the other hand, in the cylindrical inner sidewall of the cylindrical sintered body 110 in the comparative example in which the length in the cylindrical axial direction is 957 mm or more, crystal grains are smaller than those on the outer side and crystal grains in the initial stage of growth are observed. Since the crystal grains in the cylindrical inner surface of the cylindrical sintered body 110 in this comparative example are in an initial stage of growth, they are small, uneven, and lack smoothness.

The cylindrical sintered body described above can be obtained by sintering the cylindrical shaped body while supplying oxygen in the cylindrical axis direction.

2 is a cross-sectional view showing an example of the configuration of a cylindrical sputtering target after assembly according to the embodiment of the present invention. As shown in Fig. 2, the cylindrical sputtering target 100 after the assembly has the cylindrical base material 130 disposed on the inner hollow portion of the cylindrical sintered body 110 shown in Fig. The cylindrical substrate 130 and the cylindrical sintered body 110 are soldered by the brazing material 140 and the adjacent cylindrical sintered bodies 110 are disposed via the space 120. [

The material of the cylindrical substrate 130 has a high thermal conductivity so as to efficiently discharge heat generated by electrons or ions colliding with the target when the target is sputtered and has conductivity sufficient to apply a bias voltage to the target A metal material having a small particle size can be used. Concretely, copper (Cu), titanium (Ti), an alloy containing them, and stainless steel (SUS) can be used.

The material of the brazing material 140 may be a material having a high thermal conductivity and conductivity and sufficient adhesion and strength to support the cylindrical sintered body 110 such as the cylindrical substrate 130. However, the thermal conductivity of the brazing material 140 may be lower than the thermal conductivity of the cylindrical base material 130. Further, the conductive material of the brazing material 140 may be a material lower than the conductivity of the cylindrical base material 130. As the brazing material 140, for example, indium (In), tin (Sn), and alloys containing them may be used.

As described above, according to the sputtering target according to the present embodiment, by setting the length and the relative density of the cylindrical sintered body within the above-described range, it is possible to improve the mechanical strength of the cylindrical sintered body and to reduce impurities in the thin film using the cylindrical sintered body, The effect of improving the density can be obtained. Further, by setting the difference in the relative density between the solid and the solid in the cylindrical sintered body within the above ranges, it is possible to suppress the electric field distortion in the divided sputtering target having a plurality of cylindrical sintered bodies. As a result, a stable discharge characteristic can be obtained at the time of sputtering, and a thin film having a very high in-plane uniformity of film quality can be formed on a large substrate exceeding the size of one cylindrical sintered body. In addition, by setting the cylindrical inner sidewall and the cylindrical outer sidewall state of the cylindrical sintered body within the above-mentioned ranges, it is possible to maintain a stable quality over the target life in the divided sputtering target having the cylindrical sintered body. In other words, the characteristic change does not occur while the target is continuously used, and generation of nodules or particles due to density defects can be suppressed.

[Manufacturing method of cylindrical sintered body]

Next, a method of manufacturing a cylindrical sintered body of a cylindrical sputtering target according to the present invention will be described in detail with reference to FIG. 3 is a process flow showing a method of manufacturing a cylindrical sintered body according to an embodiment of the present invention. In Fig. 3, a method of manufacturing an ITO sintered body is illustrated. However, the material of the sintered body is not limited to ITO but can be used as another sintered metal oxide such as IGZO.

First, the raw material is prepared. As a raw material used for mixing, for example, a metal element contained in an oxide, an alloy, or the like is used. The raw material may be in the form of powder, and may be appropriately selected according to the composition of the target sputtering target. For example, in the case of ITO, a powder of indium oxide and a powder of tin oxide are prepared (steps S301 and S302). The purity of such a raw material may be usually 2N (99 mass%) or more, preferably 3 N (99.9 mass%) or more, and still more preferably 4 N (99.99 mass%) or more. If the purity is lower than 2N, impurities are contained in the cylindrical sintered body so much that the desired properties can not be obtained (for example, decrease in transmittance, increase in the resistance value of the film, There is a problem in the generation of particles.

Next, the raw material powder is pulverized and mixed (step S303). The pulverizing and mixing treatment of the raw powder can be carried out by a dry method using balls or beads such as zirconium oxide, alumina or nylon resin, a media agitating mill using the balls or beads, a media- , A mechanical agitation type, or an air flow type wet method. In general, since the wet method has better pulverizing and mixing ability than the dry method, it is preferable to carry out the mixing using the wet method.

The composition of the raw material is not particularly limited, but it is preferable to adjust it appropriately according to the composition ratio of the target sputtering target.

Here, when the raw material powder having a fine particle diameter is used, it is possible to increase the density of the sintered body. Further, it is possible to obtain finer raw powder by strengthening the grinding conditions, but the amount of the medium (zirconium oxide or the like) to be used at the time of grinding also increases, and the impurity concentration in the product increases. As described above, it is necessary to set an appropriate range for the conditions at the time of grinding while observing the densification of the sintered body and the balance of the impurity concentration in the product.

Next, the slurry of the raw material powder is dried and granulated (step S304). Here, the rapid dry assembly in which the slurry is rapidly dried may be performed. Rapid dry assembly may be performed by adjusting the hot air temperature and air flow using a spray dryer. By rapid dry granulation, it is possible to inhibit the separation of the indium oxide powder and the tin oxide powder from each other due to the difference in the settling velocity due to the specific gravity difference of the raw material powder. By assembling in this manner, the proportion of the compounding ingredients is made uniform, and the handling property of the raw material powder is improved. In addition, preliminary firing may be performed before and after the assembly.

Next, a cylindrical shaped body is formed by press-molding a mixture obtained by the above-described mixing and granulating step (plasticized when a plasticizing step is provided) (S305). By such a process, it is molded into a shape very suitable for a target sputtering target. The length of the cylindrical formed body in the axial direction of the cylinder can be 600 mm or more. The molding process may be, for example, mold molding, injection molding, injection molding or the like. In order to obtain a complicated shape such as a cylindrical shape, it is preferable to form it by cold isostatic pressing (CIP) or the like. In molding by CIP, a raw material powder weighed at a predetermined weight is filled in a rubber mold. At this time, by filling the rubber mold while swinging or tapping, uneven filling of the raw material powder in the mold and voids can be eliminated. The molding pressure by CIP is preferably 100 MPa or more and 200 MPa or less. By adjusting the molding pressure as described above, in the present embodiment, a cylindrical molded body having a relative density of 54.5% or more and 58.0% or less can be formed. More preferably, by adjusting the molding pressure of the CIP to 150 MPa or more and 180 MPa or less, a cylindrical molded body having a relative density of 55.0% or more and 57.5% or less can be obtained.

Next, the cylindrical formed body obtained in the forming step is sintered (step S306). Here, a method of sintering the cylindrical formed body will be described in detail with reference to Figs. 4 to 6. Fig. 4 is a perspective view showing a step of sintering a cylindrical formed body in the method of manufacturing a cylindrical sintered body according to the embodiment of the present invention. 5 is a cross-sectional view showing a step of sintering a cylindrical formed body in the method of manufacturing a cylindrical sintered body according to the embodiment of the present invention. 6 is a plan view showing a step of sintering a cylindrical formed body in the method of manufacturing a cylindrical sintered body according to the embodiment of the present invention.

4, the cylindrical formed body 111 obtained in the forming step S305 is formed so that the cylinder axis direction is substantially perpendicular to the sintering stage 200 on the flat sintering stage 200 As shown in FIG. However, the present invention is not limited to this as long as the cylindrical formed body 111 can be stably placed on the sintering stage 200. For example, the cylindrical formed body 111 may be arranged in an inclined state with respect to the sintering stage 200. Although not shown in FIG. 4, when the cylindrical formed body 111 is sintered, a spacer may be disposed between the cylindrical formed body 111 and the sintered stage 200. In this case, the spacer can be disposed so as to be in contact with the bottom surface 150 with an area smaller than the bottom surface 150 of the cylindrical formed body 111. By arranging the spacers, even when the volume of the cylindrical formed body 111 is reduced in the sintering process, the coefficient of friction generated by the movement can be suppressed. Therefore, it is possible to suppress the occurrence of internal stress generated in the cylindrical sintered body after sintering.

As shown in Figs. 5 and 6, the cylindrical formed body 111 obtained in the forming step of step S305 is disposed on the sintering stage 200, which can be opposed to the chamber 300. The cylindrical formed body 111 is sintered in a state where the oxygen supply port 230 provided in the plate-shaped sintering stage 200 is disposed at the center of the cylinder. The oxygen supply port 230 is smaller than the inner periphery of the cylindrical formed body 111 in consideration of reduction by the sintering process, and makes it possible to supply oxygen to the inner surface of the cylinder. The oxygen supply port 230 is disposed upward from below the cylindrical axis of the cylindrical formed body 111. The opening provided in the sintering stage 200 may be the oxygen supply port 230. One oxygen supply port 230 is directly connected to one pipe 240 for supplying oxygen. The pipe 240 is connected to the oxygen supply port 230 from the outside of the chamber 300 through, for example, a controller, a valve, or the like. That is, the oxygen supplied from the pipe 240 selectively supplies oxygen to the inner surface of the cylinder from the oxygen supply port 230 without leaking from other areas of the sintering stage 200. By adopting such a configuration, the amount of oxygen supplied from the oxygen supply port 230 can be appropriately adjusted in accordance with the length, the thickness, and the size of the cylindrical inner space in the cylindrical axial direction of the cylindrical formed body 111. For example, the longer the length in the axial direction of the cylinder, the larger the amount of oxygen supplied from the oxygen supply port 230 may be. However, the present invention is not limited to this. For example, when the thickness of the cylindrical formed body 111 is large, the amount of oxygen supplied from the oxygen supply port 230 may be further increased. Further, for example, when the inner diameter of the cylindrical sintered body is large and the inner space of the cylinder is large, the amount of oxygen supplied from the oxygen supply port 230 may be further increased.

The upper limit of the oxygen amount supplied from the oxygen supply port 230 is not particularly limited, but may be 150 L / min or less. A large amount of oxygen is supplied from one oxygen supply port 230 to cause problems such as deformation and fragmentation of the cylindrical sintered body during sintering and reduction in density of the cylindrical sintered body after sintering due to the cooling effect by oxygen . Therefore, a baffle plate or the like can be disposed in the direction of oxygen flow from the oxygen supply port 230. Oxygen supplied from the oxygen supply port 230 can be diffused in the cylindrical inner space by colliding with a sama plate or the like. The oxygen supplied from the oxygen supply port 230 may be supplied after the piping or the like is preheated during the circulation.

When oxygen is supplied to the hollow inside of the cylinder under an air atmosphere, oxygen heavier than nitrogen is gradually filled from the lower side of the cylinder axis direction. Therefore, oxygen can be supplied uniformly to the inner surface of the cylinder of the cylindrical formed body during sintering. When the inner hollow portion of the cylindrical formed body is filled with oxygen, the further supplied oxygen flows out from the upper side of the cylindrical formed body through the hollow inner portion of the cylinder to the outside of the cylinder. The outflowed oxygen flows downward from the ceiling portion of the chamber 300, and a flow of oxygen circulating in the chamber 300 occurs. Therefore, the oxygen concentration in the chamber 300 may be uniform. Separately, there may be a supply of oxygen from the wall portion of the chamber 300 to the outside of the cylinder. In this case, by adjusting the supply amount of oxygen to the inner hollow portion of the cylinder and the supply amount of oxygen to the outer side of the cylinder, the oxygen concentration on the inner side surface and the outer side surface of the cylindrical shaped article during sintering can be made uniform.

Here, in FIG. 4, a method of supplying oxygen from below is illustrated in the cylindrical inner hollow portion of the cylindrical formed body 111, but the method is not limited thereto. For example, oxygen can be supplied from below or above the cylindrical axis direction. By supplying oxygen in the cylindrical axis direction of the cylindrical formed body 111, it is possible to uniformly maintain the oxygen concentration in the cylindrical axis direction during incineration.

In addition, although FIG. 4 exemplifies the method of supplying oxygen from the oxygen supply port 230 arranged at the center of the cylinder of the cylindrical formed body 111, the present invention is not limited to this method. As long as oxygen is uniformly supplied to the inner hollow portion of the cylinder, the oxygen inlet 230 is not limited to the center of the cylinder. The oxygen supply port 230 may be plural. Further, oxygen may be supplied not only on the inner side of the cylinder but also on the outer side of the cylinder. At this time, each of the oxygen supply ports 230 is directly connected to the pipe 240 for supplying oxygen so that the oxygen supply amount can be independently controlled. As a result, the amount of oxygen supplied from each of the oxygen feed ports 230 is determined by the length, the thickness, the size of the cylindrical inner space, and the length of the cylindrical shaped body 111 in the axial direction of the cylindrical formed body 111, The position of the cylindrical formed body 111, and the like.

In general ITO sintering, sintering in an oxygen atmosphere is indispensable for increasing the density of the sintered body. Even in the sintering under the oxygen atmosphere, in the step of sintering the cylindrical formed body 111 having a length of 600 mm or more, oxygen deficiency occurs in the inner hollow portion of the cylinder due to insufficient gas convection in the cylinder inner hollow portion. The deformation and fracture of the cylindrical sintered body during sintering due to oxygen shortage in the inner hollow portion of the cylinder and the decrease in the density of the cylindrical sintered body after sintering and the difference in relative density in the cylindrical axis direction of the cylindrical sintered body, The size of the hole or the number of the holes is increased. In order to prevent the inner hollow portion from being affected by the oxygen deficiency, in the present embodiment, when the cylindrical formed body 111 is sintered, the oxygen supply port 230 ), It is possible to uniformly fill the inner hollow portion of the cylindrical formed body 111 having a diameter of 600 mm or more with oxygen. Furthermore, by combining the supply of oxygen to the inner hollow portion of the cylinder and the supply of oxygen to the outer side of the cylinder, it is possible to make the oxygen concentration at the inner side surface and the outer side surface of the cylindrical shaped article 111 during sintering uniform. As a result, deformation and fracture of the cylindrical sintered body during sintering can be prevented. Further, the density of the cylindrical sintered body after sintering can be improved. Further, the relative density difference in the cylindrical axis direction in the solid of the cylindrical sintered body can be reduced. It is possible to reduce the size and number of holes in the inner surface of the cylinder.

Returning to Fig. 3, the description of the method of manufacturing the cylindrical sintered body will be continued. The sintering in the step S306 described in detail above can be performed using an electric furnace, hot isostatic pressing (HIP), or microwave baking. The sintering conditions can be appropriately selected according to the composition of the sintered body. For example, if the ITO containing 10 wt.% Of SnO ₂ is sintered under the conditions of oxygen gas atmosphere, 1500 ° C or higher and 1600 ° C or lower, can do. When the sintering temperature is lower than 1500 캜, the density of the target is lowered. On the other hand, when the temperature exceeds 1600 占 폚, the damage to the electric furnace or furnace material is large and the maintenance is required in a timely manner, so that the working efficiency is remarkably lowered. If the sintering time is less than 10 hours, the density of the target is lowered. If the sintering time is longer than 20 hours, the holding time in the sintering process becomes longer, and the operating rate of the electric furnace becomes worse. In addition, the consumption amount of oxygen gas used in the sintering process and the electric power for operating the electric furnace are increased. The sintering pressure may be an atmospheric pressure or a reduced pressure or pressurized atmosphere.

Here, in the case of sintering in an electric furnace, the occurrence of cracks can be suppressed by adjusting the heating rate and the temperature-decreasing rate of sintering. Specifically, the heating rate of the electric furnace at sintering is preferably 300 ° C / hour or less, more preferably 180 ° C / hour or less. It is preferable that the temperature lowering rate of the electric furnace at sintering is 600 DEG C / hour or less. In addition, the heating rate or the heating rate may be adjusted to change stepwise.

The cylindrical shaped body is shrunk by the sintering process, but the temperature is held in the middle of the temperature rise so as to make the temperature in the furnace uniform before entering the temperature region in which the heat shrinkage starts in common to all the materials. As a result, temperature unevenness in the furnace is eliminated, and all of the sintered bodies provided in the furnace shrink uniformly. In addition, a suitable sintering density can be obtained by setting appropriate conditions for the material temperature and the holding time. A cylindrical sintered body having a length in the axial direction of the cylinder of 600 mm or more is sintered to form a cylindrical sintered body having a length in the axial direction of the cylinder of about 470 mm or more.

Next, the cylindrical sintered body thus formed is machined into a desired cylindrical shape using a machining machine such as a plane grinding machine, a cylindrical grinding machine, a lathe, a cutter, or a machining center (step S307). The machining is carried out so as to make the cylindrical sintered body suitable for mounting to the sputtering apparatus, and is also performed so as to have a desired surface roughness. Here, the average surface roughness (Ra) of the cylindrical sintered body is preferably 0.5 mu m or less in order to obtain flatness to such an extent that the electric field concentrates and no abnormal discharge occurs during sputtering. By the above process, a cylindrical sintered body having high density and high homogeneity can be obtained.

Next, the machined cylindrical sintered body is bonded to the substrate (step S308). Particularly, in the case of a cylindrical sputtering target, a cylindrical sintered body is bonded to a cylindrical base material called a backing tube by using a brazing material as an adhesive. By the above process, a cylindrical sputtering target using the above-described cylindrical sintered body can be obtained.

As described above, according to the manufacturing method of the cylindrical sputtering target related to the embodiment, by supplying oxygen to the hollow inside of the cylinder of the cylindrical formed body in the sintering process, deformation and disruption of the cylindrical sintered body during sintering can be prevented. Further, the density of the cylindrical sintered body after sintering can be improved. Further, the difference in relative density in the cylindrical axis direction of the sintered cylindrical body after sintering can be reduced. It is possible to reduce the size of the holes observed on the inner surface of the cylindrical sintered body after sintering. In addition, it is possible to reduce the number of holes observed in the cylindrical inner surface of the cylindrical sintered body after sintering. Thus, it is possible to provide a cylindrical sintered body and a cylindrical sputtering target having high homogeneity in the solid body and between the individual bodies.

&Lt; Modification Example 1 &

A sintering method of a cylindrical sintered body according to a first modification of the embodiment of the present invention will be described with reference to Fig.

7 is a plan view showing a step of sintering a cylindrical formed body in a method of manufacturing a cylindrical sintered body according to Modification 1 of the embodiment of the present invention. In Fig. 7, in the step of sintering the cylindrical formed body 111, sixteen oxygen supply openings 230 are arranged. At this time, each of the oxygen supply ports 230 is directly connected to the pipe 240 for supplying oxygen so that the oxygen supply amount can be independently controlled. Thus, the amount of oxygen supplied from each of the oxygen feed ports 230 is determined by the length, the thickness, the size of the cylindrical inner space, and the oxygen supply amount to the cylindrical formed body 111 in the axial direction of the cylindrical formed body 111 The position of the sphere 230, and the like.

In Fig. 7, the eight oxygen supply ports 230 are evenly arranged through the walls of the cylindrical formed body 111. In other words, eight oxygen supply ports 230 are arranged along the inner and outer sides of the cylinder of the cylindrical formed body 111, respectively. 7, the eight oxygen supply openings 230a are located inside the cylinder of the cylindrical formed body 111, and the eight oxygen supply openings 230b are located outside the cylinder of the cylindrical formed body 111, (Hereinafter referred to as the oxygen supply port 230 when the oxygen supply port 230a and the oxygen supply port 230b are not distinguished). However, the present invention is not limited to this, and the number, size, and arrangement of the oxygen supply ports 230 are not limited as long as the cylindrical formed body 111 can be stably placed on the sintering stage 200. The oxygen supply port 230 may be disposed not only inside the cylinder of the cylindrical formed body 111 but also outside the cylinder. In other words, oxygen may be supplied not only to the inner surface of the cylinder but also to the outer surface of the cylinder.

For example, when the length of the cylindrical formed body 111 is long, the oxygen supply amount from the oxygen supply port 230a located on the inner side of the cylinder where the convection current is bad is larger than the oxygen supply amount from the oxygen supply port 230b outside the cylinder So that the oxygen concentration at the inner and outer sides of the cylinder can be finally adjusted to be uniform. It is also possible to supply oxygen only from the oxygen supply port 230a located inside the cylinder. The amount of oxygen supplied by each oxygen supply port 230a may correspond to, for example, 1/8 of the supply amount when oxygen is supplied from one oxygen supply port 230 in the embodiment of the present invention have. Further, the oxygen amounts supplied by the respective oxygen supply ports 230a may not be equal to each other, and may be different from each other. That is, the total sum of the oxygen supply amounts from the plurality of oxygen supply ports 230a may be the supply amount when oxygen is supplied from one oxygen supply port 230 in the embodiment of the present invention. Further, the longer the length in the axial direction of the cylinder, the larger the sum of the amounts of oxygen supplied from the oxygen supply port 230 may be. However, the present invention is not limited to this. For example, when the thickness of the cylindrical formed body 111 is large, the total amount of oxygen supplied from the oxygen supply port 230a may be further increased. Further, for example, when the inner diameter of the cylindrical sintered body is large and the inner space of the cylinder is large, the total amount of oxygen supplied from the oxygen supply port 230a may be further increased.

The upper limit of the oxygen amount supplied from the oxygen supply port 230 is not particularly limited, but may be 150 L / min or less. By supplying oxygen from the plurality of oxygen supply ports 230a, the supply amount of oxygen can be dispersed, and the gas convection in the hollow inside of the cylinder can be controlled. It is also possible to suppress the problems such as deformation and fracture of the cylindrical sintered body during sintering due to the cooling effect by oxygen and lowering of the density of the cylindrical sintered body after sintering. However, the oxygen supplied from the plurality of oxygen supply ports 230a may be further diffused in the inner space of the cylinder through the sama plate or the like. The oxygen supplied from the oxygen supply port 230 may be supplied after the piping or the like is preliminarily heated in circulation.

In general ITO sintering, sintering in an oxygen atmosphere is indispensable for increasing the density of the sintered body. Even in the sintering under the oxygen atmosphere, in the step of sintering the cylindrical formed body 111 having a length of 600 mm or more, oxygen deficiency occurs in the cylinder due to insufficient gas convection in the hollow inside the cylinder. The deformation and fracture of the cylindrical sintered body during sintering due to oxygen deficiency in the cylinder, the decrease of the density of the cylindrical sintered body after sintering, the difference in relative density in the cylindrical axis direction of the cylindrical sintered body, Size, or number of holes. In order to prevent the influence of oxygen shortage in the cylinder, in the present embodiment, the oxygen supply amount from the oxygen supply port 230a located inside the cylinder is made larger than the oxygen supply amount from the oxygen supply port 230b outside the cylinder So that it is possible to finally adjust the oxygen concentration on the inner side surface and the outer side surface of the cylinder to be uniform. The oxygen supply amount from the oxygen supply port 230a located on the inner side of the cylinder may be further increased so that the oxygen concentration on the inner side of the cylinder is finally higher than the oxygen concentration on the outer side of the cylinder. It is also possible to supply oxygen only from the oxygen supply port 230a located on the inner side of the cylinder and to prevent the supply of oxygen from the oxygen supply port 230b on the outer side of the cylinder. Each of the oxygen supply ports 230 is directly connected to the pipe 240 for supplying oxygen so that the oxygen supply amount can be independently controlled. By supplying oxygen from the plurality of oxygen supply ports 230a, it is possible to more uniformly supply oxygen on the inner surface of the cylinder. As a result, it is possible to control the oxygen concentration at the inner side surface and the outer side surface of the cylinder of the cylindrical shaped body during sintering, so that deformation and fracture of the cylindrical sintered body during sintering can be prevented. Further, the density of the cylindrical sintered body after sintering can be improved. In addition, the relative density difference in the cylindrical axis direction of the cylindrical sintered body after sintering can be reduced. It is possible to reduce the circle equivalent diameter of the area in the hole observed in the inner surface of the cylinder of the sintered cylindrical body after sintering. Further, it is possible to reduce the number of holes observed in the inner surface of the cylinder of the sintered cylindrical body after sintering.

&Lt; Modification Example 2 &

A sintering method of a cylindrical sintered body according to a second modification of the embodiment of the present invention will be described with reference to Fig. In this modified example, except for the sama plate 260, since it is the same as the embodiment of the present invention, detailed description thereof will be omitted.

8 is a cross-sectional view showing a step of sintering a cylindrical formed body in a method of manufacturing a cylindrical sintered body according to a second modification of the embodiment of the present invention. 8, in the step of sintering the cylindrical formed body 111, one oxygen supply port 230 is disposed. The oxygen supply port 230 is directly connected to the pipe 240 for supplying oxygen so that the oxygen supply amount can be independently controlled. A sama plate 260 is disposed in the direction of oxygen flow from the oxygen supply port 230. In this modification, the syringe plate 260 has a cap-like shape so as to surround the oxygen supply port 230. The samaa plate 260 has a plurality of openings 280 in a cap-shaped sidewall portion. The oxygen supplied from the oxygen supply port 230 contacts the inner ceiling portion of the syringe plate 260 and flows out from the plurality of openings 280 of the syringe plate 260 in a dispersed state. Oxygen flowing out from the plurality of openings 280 of the syringe plate 260 gradually fills up from the lower side in the cylinder axis direction and rises in the cylindrical axis direction at the hollow inside the cylindrical molding. However, the shape of the sama plate 260 is not limited to this, and the sama plate 260 may have a shape that diffuses oxygen supplied from the oxygen supply port 230 in the cylindrical inner space. The sama plate 260 may overlap at least a part of the oxygen supply port 230 when viewed from the side of the advancing direction of oxygen, for example. As a result, deformation and fracture of the cylindrical sintered body during sintering due to the cooling effect and reduction in density of the cylindrical sintered body after sintering, which are caused by supplying a large amount of oxygen from one oxygen supply port 230, .

Further, the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention.

[Example]

[Production of cylindrical sintered body]

[Example 1]

In Embodiment 1, a method of manufacturing a cylindrical ITO target material (cylindrical sintered body) will be described. First, 4N indium oxide having a BET (Brunauer, Emmett Teller 'sequencing) specific surface area of 4.0 to 6.0 m ² / g and a 4N tin oxide having a BET specific surface area of 4.0 to 5.7 m ² / g or less were prepared as raw material powders. Here, the BET specific surface area is the surface area determined by the BET method. The BET method is a gas adsorption method in which gaseous molecules such as nitrogen, argon, krypton, and carbon oxide are adsorbed on solid particles and the specific surface area of the solid particles is measured from the adsorbed amount of gaseous molecules. Here, the raw material was weighed so that the indium oxide was 90 mass% and the tin oxide was 10 mass%. Next, these raw material powders were pulverized with a wet ball mill and mixed. Here, zirconium oxide balls were used as a milling medium. The mixed slurry was rapidly dried and assembled by a spray dryer.

Next, the mixture obtained by the above assembling step was formed into a cylindrical shape by molding with CIP. The pressure during molding by CIP was 176 MPa.

The parameters of the cylindrical formed body of Example 1 obtained by the above-described molding process are as follows.

· Cylinder outer diameter (diameter) = 194.0 mm

· Cylindrical inner diameter (diameter) = 158.7 mm

· Thickness of cylinder = 17.65 mm

· Length in the cylinder axis direction = 600 mm

Next, the cylindrical formed body obtained by CIP was sintered using an electric furnace. The sintering conditions are as follows.

· Heating rate = 300 ° C / hour

· High temperature holding temperature = 1560 ℃

· High-temperature holding time = 20 hr

· Atmosphere during sintering = oxygen atmosphere

· Sintering pressure = atmospheric pressure

· Introduction of oxygen to the inner hollow of the cylinder = 50 L / min

· Oxygen introduction outside the cylinder = 0 L / min

The parameters of the cylindrical sintered body obtained by the above-described sintering process are as follows.

· Cylinder outer diameter (diameter) = 155.2 mm

· Cylindrical inner diameter (diameter) = 127.0 mm

· Thickness of cylinder = 14.1 mm

· Length in the cylindrical axis direction = 478 mm

Sinter density = 7.134 g / cm &lt; ³ &gt;

Relative density of sintered body = 99.68%

· Bulk resistance value of sintered body = 0.11 m? · Cm

[Example 2]

In the second embodiment, a cylindrical sintered body obtained by sintering a cylindrical formed body elongated in the axial direction of the cylinder in comparison with the first embodiment will be described. The forming process of the cylindrical formed body is the same as that of the first embodiment, and a description thereof will be omitted.

The parameters of the cylindrical formed body of Example 2 obtained by the same molding process as in Example 1 are as follows.

· Cylinder outer diameter (diameter) = 193.8 mm

· Cylindrical inner diameter (diameter) = 158.2 mm

· Thickness of the cylinder = 17.8 mm

· Length in the cylinder axis direction = 1200 mm

Next, the cylindrical formed body was sintered using an electric furnace. The sintering conditions of Example 2 are the same as those of Example 1 except for the parameter of introduction of oxygen into the hollow portion inside the cylindrical formed body, and the explanation is omitted.

· Introduction of oxygen into the inner hollow of the cylinder = 100 L / min

· Oxygen introduction outside the cylinder = 0 L / min

The parameters of the cylindrical sintered body obtained by the above-described sintering process are as follows.

· Cylinder outer diameter (diameter) = 155.0 mm

· Cylinder inner diameter (diameter) = 126.6 mm

· Thickness of cylinder = 14.2 mm

· Length in the cylindrical axis direction = 948 mm

Sinter density = 7.132 g / cm &lt; ³ &gt;

Relative density of sintered body = 99.65%

Bulk resistance value of sintered body = 0.12 m? 占 cm m

[Example 3]

In the third embodiment, a cylindrical sintered body obtained by sintering an even longer cylindrical shaped body in the axial direction of the cylinder is described as compared with the first and second embodiments. The forming process of the cylindrical formed body is the same as that of the first embodiment, and a description thereof will be omitted.

The parameters of the cylindrical formed body of Example 3 obtained by the same molding process as in Example 1 are as follows.

· Cylinder outer diameter (diameter) = 194.2 mm

· Cylindrical inner diameter (diameter) = 158.5 mm

· Thickness of the cylinder = 17.85 mm

· Length in the cylinder axis direction = 1755 mm

Next, the cylindrical formed body was sintered using an electric furnace. The sintering conditions of Example 3 are the same as those of Example 1 except for the parameter of introduction of oxygen into the hollow portion inside the cylindrical formed body, and a description thereof will be omitted.

· Introduction of oxygen into the inner hollow of the cylinder = 150 L / min

· Oxygen introduction outside the cylinder = 0 L / min

The parameters of the cylindrical sintered body obtained by the above-described sintering process are as follows.

· Cylinder outer diameter (diameter) = 155.4 mm

· Cylindrical inner diameter (diameter) = 126.8 mm

· Thickness of cylinder = 14.3 mm

· Length in the cylindrical axis direction = 1386 mm

Sinter density = 7.130 g / cm &lt; ³ &gt;

Relative density of sintered body = 99.62%

Bulk resistance value of sintered body = 0.12 m? 占 cm m

Next, comparative examples of the cylindrical formed body and the cylindrical sintered body shown in the above Examples 1 to 3 will be described below. In the following comparative examples, a cylindrical sintered body obtained by sintering under the condition that no oxygen is introduced into the inner hollow portion of the cylindrical formed body will be described, unlike the embodiment. Further, in the comparative example, instead of introduction of oxygen into the inner hollow portion of the cylindrical formed body, sintering was performed under oxygen introduction conditions from the chamber wall portion to the outside of the cylindrical shaped body. The forming process of the cylindrical formed body is the same as that of the first embodiment, and a description thereof will be omitted.

[Comparative Example 1]

The parameters of the cylindrical formed article of Comparative Example 1 obtained by the same molding process as in Example 1 are as follows.

· Cylinder outer diameter (diameter) = 194.9 mm

· Cylindrical inner diameter (diameter) = 159.0 mm

· Thickness of cylinder = 17.95 mm

· Length in the cylinder axis direction = 480 mm

Next, the cylindrical formed body was sintered using an electric furnace. The sintering conditions of Comparative Example 1 are the same as those of Embodiment 1 except for the parameter of introduction of oxygen into the cylindrical formed body, and a description thereof is omitted.

· Introduction of oxygen to the inner hollow of the cylinder = 0 L / min

· Introduction of oxygen to the outside of the cylinder = 100 L / min

The parameters of the cylindrical sintered body obtained by the above-described sintering process are as follows.

· Cylinder outer diameter (diameter) = 155.9 mm

· Cylindrical inner diameter (diameter) = 127.2 mm

· Thickness of cylinder = 14.35 mm

· Length in the cylindrical axis direction = 385 mm

Sinter density = 7.133 g / cm &lt; ³ &gt;

Relative density of sintered body = 99.66%

· Bulk resistance value of sintered body = 0.11 m? · Cm

[Comparative Example 2]

The respective parameters of the cylindrical formed body of Comparative Example 2 obtained by the molding process as in Example 1 are as follows.

· Cylinder outer diameter (diameter) = 193.5 mm

· Cylindrical inner diameter (diameter) = 158.2 mm

· Thickness of cylinder = 17.65 mm

· Length in the cylinder axis direction = 600 mm

Next, the cylindrical formed body was sintered using an electric furnace. The sintering conditions of Comparative Example 2 are the same as those of Embodiment 1 except for the parameter of introduction of oxygen into the cylindrical formed body, and the explanation is omitted.

· Introduction of oxygen to the inner hollow of the cylinder = 0 L / min

· Introduction of oxygen to the outside of the cylinder = 100 L / min

The parameters of the cylindrical sintered body obtained by the above-described sintering process are as follows.

· Cylinder outer diameter (diameter) = 156.7 mm

· Cylindrical inner diameter (diameter) = 128.1 mm

· Thickness of cylinder = 14.3 mm

· Length in the cylindrical axis direction = 485 mm

Sinter density = 7.041 g / cm &lt; ³ &gt;

Relative density of sintered body = 98.38%

Bulk resistance value of sintered body = 0.12 m? 占 cm m

[Comparative Example 3]

The respective parameters of the cylindrical formed body of Comparative Example 3 obtained by the molding process as in Example 1 are as follows.

· Cylinder outer diameter (diameter) = 194.1 mm

· Cylindrical inner diameter (diameter) = 158.2 mm

· Thickness of cylinder = 17.95 mm

· Length in the cylinder axis direction = 1200 mm

Next, the cylindrical formed body was sintered using an electric furnace. The sintering conditions of Comparative Example 3 are the same as those of Embodiment 1 except for the parameter of introduction of oxygen into the cylindrical formed body, and a description thereof is omitted.

· Introduction of oxygen to the inner hollow of the cylinder = 0 L / min

· Introduction of oxygen to the outside of the cylinder = 100 L / min

The parameters of the cylindrical sintered body obtained by the above-described sintering process are as follows.

· Cylinder outer diameter (diameter) = 157.2 mm

· Cylindrical inner diameter (diameter) = 128.1 mm

· Thickness of cylinder = 14.55 mm

· Length in the cylinder axis direction = 957 mm

Sinter density = 7.038 g / cm &lt; ³ &gt;

Relative density of sintered body = 98.34%

Bulk resistance value of sintered body = 0.12 m? 占 cm m

In Comparative Example 3, deformation by sintering was confirmed.

[Comparative Example 4]

The parameters of the cylindrical formed body of Comparative Example 4 obtained by the same molding process as in Example 1 are as follows.

· Cylinder outer diameter (diameter) = 194.2 mm

· Cylindrical inner diameter (diameter) = 158.4 mm

· Thickness of cylinder = 17.9 mm

· Length in the cylinder axis direction = 1410 mm

Next, the cylindrical formed body was sintered using an electric furnace. The sintering conditions of Comparative Example 4 are the same as those of Embodiment 1 except for the parameter of introduction of oxygen into the cylindrical formed body, and a description thereof is omitted.

· Introduction of oxygen to the inner hollow of the cylinder = 0 L / min

· Introduction of oxygen to the outside of the cylinder = 100 L / min

The parameters of the cylindrical sintered body obtained by the above-described sintering process are as follows.

· Cylinder outer diameter (diameter) = 155.3 mm

· Cylindrical inner diameter (diameter) = 127.8 mm

· Thickness of cylinder = 13.75 mm

· Length in the cylindrical axis direction = 1145 mm

Sinter density = 7.042 g / cm &lt; ³ &gt;

Relative density of sintered body = 98.39%

Bulk resistance value of sintered body = 0.12 m? 占 cm m

[Comparative Example 5]

The parameters of the cylindrical formed body of Comparative Example 5 obtained by the same molding process as in Example 1 are as follows.

· Cylinder outer diameter (diameter) = 193.6 mm

· Cylindrical inner diameter (diameter) = 158.3 mm

· Thickness of cylinder = 17.65 mm

· Length in the cylindrical axis direction = 1754 mm

Next, the cylindrical formed body was sintered using an electric furnace. The sintering conditions of Comparative Example 5 are the same as those of Embodiment 1 except for the parameter of introduction of oxygen into the cylindrical formed body, and the description is omitted.

· Introduction of oxygen to the inner hollow of the cylinder = 0 L / min

· Introduction of oxygen to the outside of the cylinder = 100 L / min

The parameters of the cylindrical sintered body obtained by the above-described sintering process are as follows.

· Cylinder outer diameter (diameter) = 157.8 mm

· Cylindrical inner diameter (diameter) = 128.5 mm

· Thickness of cylinder = 14.65 mm

· Length in the cylindrical axis direction = 1394 mm

Sinter density = 7.044 g / cm &lt; ³ &gt;

Relative density of sintered body = 98.42%

Bulk resistance value of sintered body = 0.12 m? 占 cm m

[Preparation of measurement sample]

In the cylindrical sintered bodies of Examples 1 to 3 and Comparative Examples 1 to 5 described above, measurement samples for evaluating the solid-state non-uniformity of density and bulk resistance were prepared. As shown in Fig. 9, the cylindrical sintered body 110 is divided by 150 mm in the upward and downward directions in the cylinder axis direction at the time of sintering. Further, the cylindrical measurement sample having a width of 40 to 50 mm in the center of each cylindrical axis direction is further cut out, and measurement samples 110-1 (150 mm), 110-2 (300 mm), 110-3 450 mm) (name in the following table).

[Evaluation of Relative Density]

The relative density of the cylindrical sintered bodies and the respective measurement samples of the above-mentioned Examples 1 to 3 and Comparative Examples 1 to 5 was evaluated. The density of the cylindrical sintered body and each measurement sample was measured using the Archimedes method. The relative density and the relative density difference of the cylindrical sintered body and each measurement sample were calculated based on the theoretical density. The density, the relative density, and the maximum relative density difference in the cylindrical sintered body in the cylindrical sintered bodies and the respective measurement samples of Examples 1 to 3 and Comparative Examples 1 to 5 are shown in Fig.

From the results shown in Fig. 10, it was confirmed that in the cylindrical sintered bodies of Examples 1 to 3 in which oxygen was introduced into the inner hollow portion of the cylindrical formed body at the time of sintering, The relative density of the cylindrical sintered body of Example 5 was improved. In Comparative Example 1 in which the length in the axial direction of the cylinder was 470 mm or less, the relative density was improved even when oxygen was not introduced into the inner hollow portion of the cylindrical formed body. The relative density difference between the respective measurement samples of Examples 1 to 3 was lower than that of each of the measurement samples of Comparative Examples 2 to 5. In Comparative Example 1 in which the length in the axial direction of the cylinder was 470 mm or less, the relative density difference could be reduced even when oxygen was not introduced into the inner hollow portion of the cylindrical formed body. Further, by supplying oxygen to the inner surface of the cylinder of the cylindrical formed body in the sintering process, deformation, disruption, and the like during sintering can be prevented even in a cylindrical formed body having a length in the axial direction of the cylinder of 1200 mm or more.

[Evaluation of minimum oxygen supply amount]

The minimum oxygen supply amount at which a cylindrical sintered body having a density of 7.130 g / cm ³ or more was obtained by the sintering method of the cylindrical formed body in the above-described Examples and Comparative Examples. Specifically, the amount of introduction of oxygen into the inner hollow portion of the cylinder at the time of sintering was changed stepwise to obtain a cylindrical sintered body having a length in the axial direction of the cylinder of 390, 480, 950, 1200, or 1400 mm. The density of each cylindrical sintered body was measured using the Archimedes method. Among the cylindrical sintered bodies having a density of 7.130 g / cm ³ or more, the minimum oxygen supply amount is defined as a value in which the amount of oxygen introduction at the time of sintering is smallest for each length in the cylindrical axis direction. The relationship of the minimum oxygen supply amount to the length in the cylindrical axial direction of the cylindrical sintered body is shown in Fig.

As it is shown in Figure 11, the length of the cylinder axis direction of the cylindrical sintered body up to 390 mm, without the introduction of oxygen, to obtain a cylindrical sintered body density of not less than 7.130 g / cm ^3. In the case of forming a cylindrical sintered body of 480 mm, the minimum oxygen supply amount was 5 L / min or more. When forming a cylindrical sintered body of 950 mm, the minimum oxygen supply amount was 20 L / min or more. When forming a cylindrical sintered body of 1200 mm, the minimum oxygen supply amount was 30 L / min or more. When forming a cylindrical sintered body of 1400 mm, the minimum oxygen supply amount was 35 L / min or more. From the results of Figure 11, the longer the cylindrical axis direction, it can be seen that for obtaining a cylindrical sintered body density of not less than 7.130 g / cm ³ increases the amount of oxygen required. The axial length X (mm) of the cylindrical sintered body having a density of 7.130 g / cm ³ or more and the minimum oxygen supply amount Y (L / min) supplied from the oxygen supply port 230 are proportional to each other and can be expressed by the following equation .

Y = 0.0345X-12.508

[Evaluation of bulk resistance]

Bulk resistance was evaluated for the cylindrical sintered bodies and the respective measurement samples of the above-described Embodiments 1 to 3 and Comparative Examples 1 to 5. The bulk resistance value of the cylindrical sintered body and each measurement sample was measured by using a tetramer method. Bulk resistance values of the cylindrical sintered bodies of Examples 1 to 3 and Comparative Examples 1 to 5 and each measurement sample are shown in Fig.

From the results shown in Fig. 12, in the cylindrical sintered bodies and measurement samples of Examples 1 to 3 and Comparative Examples 1 to 5, the bulk resistance value on the outer surface of the cylinder was largely unchanged. Even in the embodiment in which oxygen is introduced into the hollow inside of the cylinder of the cylindrical formed body, oxygen is not sufficiently introduced into the hollow inside of the hollow cylindrical body, It can be thought that it has little effect.

[Preparation of Sample for Electron Microscope Observation]

Samples for observation by electron microscopy were prepared for the cylindrical sintered bodies of Examples 1 and 2 and Comparative Examples 2 and 3 described above. As shown in Fig. 13, the cylindrical sintered body 110 is formed by cutting out a cylindrical sample 110-4 having a width of 10 mm at the central portion in the axial direction of the cylinder, and moving the cylindrical inner side surface 110-4a and the cylindrical outer side surface 110-4b The sample for microscopic observation was cut out and mirror-polished was performed in a condition of 0.5 mm ground.

[Observation by electron microscope]

With respect to the cylindrical sintered bodies of Examples 1 and 2 and Comparative Examples 2 and 3 described above, samples for observing the inside and outside surfaces of the cylindrical sintered body by electron microscope were observed with an electron microscope (SEM). In each sample, photographs observed with a field of view of 1000 times using an electron microscope (SEM) are shown in Fig. 14 (inside the cylinder) and Fig. 15 (outside the cylinder). 16 (inside the cylinder) and 17 (outside the cylinder) show the photographs observed in the field of view at 2000 times or 5000 times by using an electron microscope (SEM) in each sample. 14 to 17 (a) Example 1, (b) Example 2, (c) Comparative Example 2, and (d) Samples for electron microscope observation of the inner side surface and the outer side surface of the cylindrical sintered product of Comparative Example 3 Were observed with an electron microscope (SEM).

Figs. 14 (a) and 14 (b) are electron micrographs of inner surfaces of the cylindrical sintered bodies in Examples 1 and 2. Fig. 15 (a) and 15 (b) are electron micrographs of the outer side surfaces of the cylindrical sintered bodies in Examples 1 and 2. Fig. Figs. 14 (c) and 14 (d) are electron micrographs of inner surfaces of the cylindrical sintered bodies in Comparative Example 2 and Comparative Example 3. Fig. Figs. 15 (c) and (d) are electron micrographs of the outer surface of the cylindrical sintered body in Comparative Example 2 and Comparative Example 3. Fig. As shown in Figs. 14 and 15, in Examples 1 and 2 in which oxygen was introduced into the cylindrical hollow portion of the cylindrical formed body at the time of sintering, the inner side surface of the cylindrical sintered body (Figs. 14A and 14B) There was no significant difference in the electron micrographs of the outer surface (Figs. 15 (a) and (b)). On the other hand, in Comparative Example 2 and Comparative Example 3 in which oxygen was not introduced into the cylindrical inner hollow portion of the cylindrical formed body at the time of sintering, compared with the cylindrical sintered body outer side (Figs. 15 (c) and (d) 14 (c) and (d)), large holes (photograph, black irregular shape) were observed. In the cylindrical inner sidewalls of the cylindrical sintered bodies in Comparative Example 2 and Comparative Example 3, many irregularly-shaped (crystal grain-shaped) holes were observed. The holes observed in the inner surface of the cylinder of the cylindrical sintered bodies in Comparative Example 2 and Comparative Example 3 were mainly observed in grain boundaries.

Next, in order to observe the state of the crystal grain, in the comparative example, the large pore-free area observed in Figs. 14 (c) and 14 (d) was observed particularly at a field of 2000 times or 5000 times. 16 (a) and 16 (b) are electron micrographs of inner surfaces of the cylindrical sintered bodies in Examples 1 and 2. 17 (a) and 17 (b) are electron micrographs of the outer side surfaces of the cylindrical sintered bodies in Examples 1 and 2. Fig. Figs. 16 (c) and 16 (d) are electron micrographs of inner surfaces of the cylindrical sintered bodies in Comparative Example 2 and Comparative Example 3. Fig. 17 (c) and 17 (d) are electron micrographs of the outer surface of the cylindrical sintered body in Comparative Example 2 and Comparative Example 3. As shown in Figs. 16 and 17, in Examples 1 and 2 in which oxygen was introduced into the cylindrical hollow portion of the cylindrical formed body at the time of sintering, the inner surface of the cylindrical sintered body (Figs. 16A and 16B) In the electron micrographs of the outer surface (Figs. 17 (a) and 17 (b)), no significant difference was observed, and the crystal grains were greatly grown. 16 (c) and 16 (c)) in Comparative Example 2 in which oxygen was not introduced into the hollow of the cylindrical body of the cylindrical formed body at the time of sintering and the length of the cylindrical axial direction was shorter than that of Comparative Example 3 17 (c)), no significant difference was observed, and the crystal grains were greatly grown. On the other hand, in Comparative Example 3 in which there is no introduction of oxygen into the cylindrical inner hollow portion of the cylindrical formed body at the time of sintering and the length of the cylindrical axial direction is longer than that of Comparative Example 2, compared with the cylindrical sintered body outer surface In the electron micrograph of the inner surface of the cylindrical sintered body (Fig. 16 (d)), crystal grains of a small initial stage of growth were observed. The crystal grains in the inner surface of the cylindrical sintered body in Comparative Example 3 are small, uneven, and insufficient smoothness because they are in an initial stage of growth.

Small and irregularly shaped (bubble-like) holes were observed on the inner side surface and the outer side surface of the cylindrical sintered bodies in Examples 1 and 2 (for example, the upper left hole in Fig. 17 (b)). In the cylindrical outer sidewalls of the cylindrical sintered bodies in Comparative Example 2 and Comparative Example 3, small and irregularly shaped (bubble-like) holes were observed. The holes observed in the cylindrical inner surface of the cylindrical sintered body in Examples 1 and 2 and in the cylindrical outer surface of the cylindrical sintered bodies in Examples 1, 2, and 3, And anywhere within the crystal.

[Evaluation of hole in inner surface of cylindrical sintered body]

In the cylindrical sintered bodies of Examples 1 to 3 and Comparative Examples 1 to 5, the structure of the cylindrical inner side surface and the outer side surface of the cylindrical sintered body in the central portion in the axial direction of the cylinder was observed by an electron microscope (SEM) , The number of holes and the circle equivalent diameter of the area in the hole were measured. In each sample, five samples for electron microscope observation were cut in the circumferential direction on the cylindrical inner surface 110-4a of the cylindrical sample 110-4. A field of view of 980 mu m x 1200 mu m was observed from each electron microscope observation sample and the average value of the circle equivalent diameters of the number of holes and the area in the holes was calculated. The circle equivalent diameter L of the area S in the hole of the cylindrical sintered body is calculated by the following formula.

[Equation 1]

Fig. 18 shows the average value of the circle-equivalent diameters of the number of holes and the area of the holes in the cylindrical inner surface of the cylindrical sintered bodies of Examples 1 to 3 and Comparative Examples 1 to 5.

18, in the cylindrical sintered bodies of Examples 1 to 3 in which oxygen was introduced into the cylindrical hollow inside of the cylindrical formed body at the time of sintering, in Comparative Examples 2 to 7 The number of holes in the inner surface of the cylinder was smaller than that of the cylindrical sintered body of No. 5. In Comparative Example 1 in which the length in the axial direction of the cylinder was 470 mm or less, the number of holes on the inner surface of the cylinder was small even when oxygen was not introduced into the inner hollow portion of the cylindrical formed body. In the cylindrical inner surface of the cylindrical sintered bodies of Examples 1 to 3, the average of the circle equivalent diameters of the areas in the holes was 1 占 퐉 or less. On the other hand, in the cylindrical inner surface of the cylindrical sintered bodies of Comparative Examples 2 to 5, the average of the circle equivalent diameters of the areas in the holes was 4 μm or more. In Comparative Example 1 in which the length in the axial direction of the cylinder was 470 mm or less, the average circle equivalent diameter of the area in the hole on the inner side surface of the cylinder was 1 μm or less even when oxygen was not introduced into the inner hollow portion of the cylindrical formed body. In addition, as shown in Fig. 18, and Examples 1 to 3 and Comparative Examples 1 to 5 The number of holes in the cylindrical outer surface of the cylindrical sintered body is either 4.25 × 10 ^-5 gae / μm ² or less, in the hole The average of the circle-equivalent diameters of the areas in the surface layer was 1 占 퐉 or less.

The results of ITO were shown in Examples 1 to 3, but cylindrical shaped bodies each having a composition of IZO, IGZO and AZO having a length in the axial direction of the cylinder of 600 mm or more were similarly sintered using the manufacturing method of the present invention . In addition, the production conditions can be appropriately changed within the scope of the present invention for each composition. As a result, deformation and fracture of the cylindrical sintered body during sintering could be prevented. In addition, the density of the cylindrical sintered body after sintering can be improved, and the difference in relative density in the cylindrical axis direction of the cylindrical sintered body after sintering can be reduced. It is possible to reduce the circle equivalent diameter of the area in the hole observed in the inner surface of the cylindrical sintered body after sintering and to reduce the number of holes observed in the inner surface of the cylindrical sintered body after sintering.

Incidentally, the present invention is not limited to the above-described embodiments, and can be changed as appropriate without departing from the spirit of the invention.

100: Cylindrical sputtering target
110: Cylindrical sintered body
111: Cylindrical shaped body
120: Space
130: Cylindrical substrate
140: Lead
150: the bottom
200: sintering stage
230: oxygen supply port
240: Piping
260: Samahan
280: opening
300: chamber

Claims (3)

In a cylindrical sintered body having a length in a cylindrical axis direction of 470 mm or more,
A circle-equivalent diameter of an area in a hole observed in a center portion of the cylindrical inner side surface in the cylindrical axis direction and a center portion of the cylindrical outer side surface is 1 μm or less on average,
The cylindrical shaft outer cylindrical inner surface and a cylindrical central portion of the direction number of the hole observed in the central portion side and the average 4.25 × 10 ^-5 gae / μm ² or less,
Wherein the holes observed at the central portion of the cylindrical inner side surface and the central portion of the cylindrical outer side are observed per at least a visual field of 1.176 mm ² at five independent points. The method according to claim 1,
And the relative density difference in the cylindrical axis direction is within 0.1%. A sputtering target having the cylindrical sintered body according to claim 1 or 2 and a substrate arranged in a cylindrical inner hollow.

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