TW202035740A - Cylindrical type sputtering target and method for producing the same - Google Patents

Abstract

To provide a cylindrical type sintered compact of 470 mm or more long in a cylindrical axial direction, a cylindrical type sputtering target and a method for producing the same. A method for producing a cylindrical type sputtering target according to one embodiment in this invention being a method for producing a cylindrical type sputtering target having a cylindrical type sintered compact, in which a cylindrical type compact of 600 mm or more long in a cylindrical axial direction on a stage provided with an oxygen feed port in contact with piping for feeding oxygen, and sintering is performed while oxygen is being fed in the cylindrical axial direction from an oxygen feed port smaller than the cylindrical inner circumference provided at the cylindrical inside of the cylindrical type compact. Also, in an another embodiment, it is possible that the stage is arranged in a chamber, and the piping for feeding oxygen is connected to the oxygen feed port from the outside of the chamber.

Description

Cylindrical sputtering target and manufacturing method thereof

The invention relates to a cylindrical sputtering target and a manufacturing method thereof. The present invention particularly relates to a method for manufacturing a cylindrical sintered body constituting a cylindrical sputtering target.

In recent years, the manufacturing technology of flat panel displays (FPD) or solar cells has developed rapidly, and is progressing towards large-scale development. And as the market for these products expands, the demand for large glass substrates has increased.

In particular, it is used in sputtering equipment for forming metal thin films or metal oxide thin films on large glass substrates. Instead of conventional flat-shaped sputtering targets, cylindrical (also called rotating or rotating) sputtering targets are used. Pieces. Compared with the flat sputtering target, the cylindrical sputtering target has the advantages of high target use efficiency, less corrosion (erosion), and less particles caused by the peeling of the deposit.

The cylindrical sputtering target used in the sputtering device for forming a thin film on the large glass substrate as described above must have a length of 3000 mm or more. Technically, it is impossible to realize integral molding manufacturing and grinding processing of cylindrical sputtering targets of such a length. Therefore, a divided sputtering target formed by connecting a plurality of cylindrical sintered bodies of tens of mm to hundreds of mm is usually constructed.

Here, not only the above-mentioned cylindrical sintered body, but also the connection of the general sintered body is required to improve the mechanical strength and improve the quality of the film using the sintered body. When a plurality of sintered bodies are joined to the base material, the sintered bodies are arranged at a certain interval. When the sintered body is arranged without gaps and joined to the base material, the sintered body will expand and contract due to the heat during sputtering, so the sintered body may collide with each other to cause cracks or chipping. On the other hand, there is no gap between the sintered bodies in the sintered body that should be sputtered. Therefore, problems such as sputtering of the constituent materials of the base material occur, and there is a problem that a thin film of the expected composition cannot be formed. Furthermore, in the split sputtering target connecting multiple sintered bodies, the relative density difference between adjacent sintered bodies (that is, the "solid deviation" of the sintered body density) will affect the thin film using the split sputtering target The quality. In this way, the shorter the connected sintered body is, the more the sputtering target will be divided, and the higher the risk of affecting the sputtering characteristics.

In order to avoid at least the aforementioned problems, it is necessary to have a manufacturing technique for manufacturing a cylindrical sintered body that is as long as possible corresponding to fewer divided sputtering targets. The problem of manufacturing a long cylindrical sintered body lies in the relative density difference in the sintered body (that is, the "solid deviation" of the sintered body density) and mechanical strength. For example, Patent Document 1 (Patent Document 1: Japanese Patent Publication H8-144056) discloses that during the sintering of an ITO target, the concentration of oxygen in the gas environment greatly affects the stability (density and strength) of the target's quality. Generally speaking, the sintering furnace used for ITO supplies oxygen from the furnace wall side.

However, in the case of a long cylindrical sintered body, since the gas convection in the cylinder during sintering is insufficient, the oxygen element in the cylinder may be insufficient. One of the problems of the present invention is to provide a cylindrical sintered sputtering target obtained by joining a plurality of sintered bodies to a base material in order to correspond to fewer divisions, and to provide a cylindrical sintered material whose length in the cylindrical axis direction is 470 mm or more Body, cylindrical sputtering target and manufacturing methods of these are one purpose. In addition, an object of the present invention is to provide a cylindrical sintered body, a cylindrical sputtering target, and a manufacturing method thereof with high homogeneity in a solid and between individuals.

The method of manufacturing a cylindrical sputtering target according to one embodiment of the present invention is that in the method of manufacturing a cylindrical sputtering target with a cylindrical sintered body, a cylindrical sputtering target is arranged on a worktable The length of the cylindrical shaped body in the direction of the cylindrical axis is more than 600 mm. The workbench is equipped with an oxygen element supply port. The oxygen element supply port is connected to the pipeline for supplying oxygen element. The oxygen element is supplied in the direction of the cylinder axis and sintered, and the oxygen element supply port is smaller than the inner circumference of the cylinder arranged inside the cylinder of the cylindrical shaped body.

In addition, in other aspects, the workbench can also be arranged in the chamber, and the pipeline for supplying oxygen can also be connected to the oxygen supply port from outside the chamber.

In addition, in other aspects, oxygen elements may be supplied toward the hollow portion inside the cylinder of the cylinder-forming body and sintered.

In addition, in other aspects, the oxygen element may be supplied from the downward direction toward the upward direction of the cylindrical shape of the cylindrical molded body and sintered.

The cylindrical sintered body used in the cylindrical sputtering target according to one embodiment of the present invention is a cylindrical sintered body with a length of 470 mm or more along the direction of the cylindrical axis and along the direction of the cylindrical axis The relative density difference is within 0.1%.

The cylindrical sintered body used in the cylindrical sputtering target according to one embodiment of the present invention is a cylindrical sintered body with a length of 470 mm or more along the axis of the cylinder, and is located on the inner side of the cylinder The equivalent circle diameter of the observed hole area is less than 1 μm on average.

The cylindrical sintered body used in the cylindrical sputtering target according to one embodiment of the present invention is a cylindrical sintered body with a length of 470 mm or more along the axis of the cylinder, and is located on the inner side of the cylinder The number of holes observed is 4.25×10 ^-5 /μm ² or less on average.

In addition, in other aspects, the holes observed on the inner surface of the cylinder can also be the holes observed at least five independent positions in the central part of the cylinder axis with a field of view of 1.176 mm ² each.

According to the present invention, it is possible to provide a cylindrical sintered body having a length of 470 mm or more in the direction of the cylindrical axis, a cylindrical sputtering target, and a manufacturing method thereof. In addition, it is also possible to provide a cylindrical sintered body, a cylindrical sputtering target with high homogeneity in a solid and between individuals, and a manufacturing method thereof.

Hereinafter, the cylindrical sputtering target of the present invention and its manufacturing method will be described with reference to the drawings. However, the cylindrical sputtering target and the manufacturing method thereof of the present invention can be implemented in a variety of different ways, and are not limitedly interpreted as the description content of the embodiments exemplified below. In addition, in the drawings referred to in this embodiment, the same parts or parts with the same function will be marked with the same symbols, and the repeated description will be omitted.

The embodiment will be described below.

The outline of the structure and structure of the cylindrical sputtering target and the cylindrical sintered body of the embodiment of the present invention will be explained using FIGS. 1 and 2.

The outline of the cylindrical sputtering target will be described below.

FIG. 1 is a perspective view of an example of a cylindrical sintered body included in 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 via a certain space. In FIG. 1, for convenience of explanation, the space of adjacent cylindrical sintered bodies 110 is enlarged. The details of the hollow inside the cylinder of the cylindrical sintered body 110 are shown in FIG. 2, and a cylindrical base material 130 for supporting the cylindrical sintered body 110 is introduced.

In addition, the thickness of the cylindrical sintered body 110 can be set to 6.0 mm or more and 20.0 mm or less. In addition, the length of the cylindrical sintered body 110 in the cylindrical axis direction can be 470 mm or more and 1500 mm or less. In addition, the outer diameter of the cylindrical sintered body 110 can be 147 mm or more and 175 mm or less. In addition, the inner diameter of the cylindrical sintered body 110 can be set to 135 mm or less. In addition, the space in the cylindrical axis direction between adjacent cylindrical sintered bodies 110 can be set to be 0.1 mm or more and 0.4 mm or less.

The material of the cylindrical sintered body 110 may be, for example, an ITO sintered body (Indium Tin Oxide) made of indium, tin and oxygen elements, an IZO sintered body (Indium Zinc Oxide) made of indium, zinc and oxygen elements, IGZO sintered body (Indium Gallium Zinc Oxide) made of indium, gallium, zinc and oxygen, AZO sintered body (Aluminum Indium Zinc Oxide) made of zinc, aluminum and oxygen, zinc oxide (ZnO), titanium dioxide (TiO ₂ ) The sintered body. However, the cylindrical sintered body of the cylindrical sputtering target used in the present invention may be a ceramic sintered body containing oxygen, and is not limited to the above composition.

Here, the density of the cylindrical sintered body 110 in this embodiment can also be 99.5% or more. The density of the cylindrical sintered body 110 can be more than 99.6%. In addition, the relative density difference in the solid of the cylindrical sintered body 110 along the cylindrical axis direction may be 0.1% or less. The relative density difference of the cylindrical sintered body 110 along the cylindrical axis direction may be 0.05% or less, and still more preferably 0.03% or less. In addition, the relative density difference between the adjacent cylindrical sintered bodies 110a and 110b, that is, the relative density difference between the solids of the cylindrical sintered bodies may also be 0.1% or less.

Among them, the density of the sintered body is expressed in terms of relative density. The relative density is based on the measured density and theoretical density, and is expressed as relative density=(measured density/theoretical density)×100(%). The relative density difference is based on the difference between the measured density and the theoretical density, and is expressed by the relative density difference=(measured density difference/theoretical density)×100(%). The theoretical density is the density value calculated from the theoretical density of the element oxide of the sintered body from the constituent elements of the sintered body. For example, if it is an ITO target, among the constituent elements of indium, tin, and oxygen, indium oxide (In ₂ O ₃ ) and tin oxide (SnO ₂ ) are used as the oxidation of indium and tin to remove oxygen. Object to calculate the theoretical density. Among them, the elemental analysis value (at% or mass%) of indium and tin in the sintered body is converted into the mass ratio of indium oxide (In ₂ O ₃ ) and tin oxide (SnO ₂ ). For example, in the case of an ITO target with 90% by mass of indium oxide and 10% by mass of tin oxide, the theoretical density is calculated by (density of In ₂ O ₃ (g/cm ³ ) × 90 + SnO ₂ Calculated by the method of density (g/cm ³ )×10)/100 (g/cm ³ ). The theoretical density of In ₂ O ₃ is 7.18 g/cm ³ and the theoretical density of SnO ₂ is 6.95 g/cm ^{3. The} calculated theoretical density is 7.157 (g/cm ³ ). In addition, if each constituent element contains Zn, it can be calculated using ZnO as an oxide, and if it contains Ga, it can be calculated using Ga ₂ O ₃ as an oxide. The theoretical density of ZnO is 5.67 g/cm ³ and the theoretical density of Ga ₂ O ₃ is 5.95 g/cm ³ . On the other hand, the measured density is the value of the weight divided by the volume. In the case of a sintered body, the volume can be calculated by the Archimedes method. The cylindrical sintered body 110 can be used to cut out cylindrical measurement samples with a width of 40-50 mm every 150 mm along the cylindrical axis direction and calculate the relative density of each sample to evaluate the cylindrical sintered body The relative density difference of the 110 solids along the cylinder axis.

As described above, by setting the length and relative density of the cylindrical sintered body within the above range, the mechanical strength of the cylindrical sintered body can be improved, and the occurrence of nodules can be suppressed when the cylindrical sintered body is used. Or suppress the particles generated with the arc, and can also reduce the impurity of the film and increase the film density. Furthermore, by setting the relative density difference in and between solids of the cylindrical sintered body within the above ranges, it is possible to suppress the distortion of the electric field in the divided sputtering target with a plurality of cylindrical sintered bodies. . Therefore, stable discharge characteristics can be obtained during sputtering, and a thin film with extremely high in-plane uniformity can be formed on a large substrate whose size exceeds a single cylindrical sintered body.

The inner solid difference of the cylindrical sintered body 110 also includes the difference between the cylindrical inner surface and the outer surface of the cylindrical sintered body 110. The state of the cylindrical inner side surface and the outer side surface of the cylindrical sintered body 110 can be evaluated by observation with an electron microscope (SEM). In this embodiment, there is no significant difference in the holes observed on the inner and outer sides of the cylinder at the center of the cylindrical sintered body 110 in the direction of the cylinder axis. In this embodiment, the shape of the holes observed on the inner and outer sides of the cylinder of the cylindrical sintered body 110 is irregular, no matter whether the crystal grain boundary or the inside of the crystal is observed. In other words, in this embodiment, no matter whether the crystal grain boundary or the inside of the crystal is observed, the shapes of the holes observed on the inner and outer sides of the cylinder of the cylindrical sintered body 110 are irregular bubble-like holes. On the other hand, the cylindrical outer surface of the cylindrical sintered body in the comparative example whose length in the direction of the cylindrical axis is 470 mm or more or the cylindrical inner surface of the cylindrical sintered body 110 in this embodiment And the outer surface, large irregular grain-shaped holes were observed on the inner surface of the cylinder in the comparative example. In other words, irregular crystal grain-like holes were observed on the inner surface of the cylinder of the cylindrical sintered body in the comparative example whose length in the cylinder axis direction was 470 mm or more. The pores observed on the inner surface of the cylinder of the cylindrical sintered body in this comparative example are mainly observed at the crystal grain boundary. There is no significant difference between the cylindrical outer surface of the cylindrical sintered body in the comparative example and the cylindrical inner and outer surfaces of the cylindrical sintered body 110 in this embodiment. In the comparative example, regardless of whether the crystal grain boundary or the inside of the crystal is observed, the holes on the outer surface of the cylinder have smaller irregular grain shapes compared to the shape of the holes observed on the inner surface of the cylinder of the cylindrical sintered body .

The shape of each hole observed on the inner surface of the cylinder and the outer surface of the cylinder of the cylindrical sintered body in this embodiment and the comparative example is irregular. Therefore, the area of a single continuous hole can be calculated from the top view, and then the size of the hole can be evaluated by the diameter of a circle with an equivalent area (hereinafter, the equivalent circle diameter of the area of the hole). A single continuous hole in the observed surface can also be regarded as a single one to calculate the number of holes. The equivalent circle diameter of the area of the hole observed on the inner surface of the cylinder of the cylindrical sintered body 110 in this embodiment can also be less than 1 μm on average. The equivalent circle diameter of the area of the hole observed on the inner surface of the cylinder of the cylindrical sintered body 110 may be 0.5 μm or less on average. In addition, the number of holes observed on the inner surface of the cylinder of the cylindrical sintered body 110 in this embodiment can also be 4.25×10 ^-5 holes/μm ² or less on average. The number of holes observed on the inner surface of the cylinder of the cylindrical sintered body 110 may be 2.125×10 ^-5 holes/μm ² or less on average. Moreover, the equivalent circle diameter of the area of the hole observed on the outer surface of the cylinder of the cylindrical sintered body 110 in the present embodiment can also be 1 μm or less on average. The equivalent circle diameter of the area of the hole observed on the outer surface of the cylinder of the cylindrical sintered body 110 may be 0.5 μm or less on average. In addition, the number of holes observed on the outer surface of the cylinder of the cylindrical sintered body 110 in this embodiment can also be 4.25×10 ^-5 holes/μm ² or less on average. The number of holes observed on the outer surface of the cylinder of the cylindrical sintered body 110 may be 2.125×10 ^-5 holes/μm ² or less on average.

Among them, the evaluation of the state of the cylindrical inner and outer sides of the cylindrical sintered body 110 is to observe five fields of 980 μm×1200 μm in the central part of the cylindrical axis direction of each sample to evaluate the holes The average value of the equivalent circle diameter of the number and the area of the hole. First, calculate the projected area S of a single continuous hole, and then calculate the diameter L of a circle with an equivalent area using the following formula to obtain the equivalent circle diameter L of the area S of the hole.

。Formula 1:

.

In this embodiment, there is no significant difference in the size of the crystal particles observed on the inner and outer sides of the cylinder at the center of the cylindrical sintered body 110 in the direction of the cylinder axis. The crystal particles observed on the inner and outer sides of the cylinder of the cylindrical sintered body 110 in the present embodiment grow in large size. On the other hand, compared with the cylindrical outer surface of the cylindrical sintered body in the comparative example whose length in the direction of the cylindrical axis is 957 mm or more, the inner surface of the cylinder in the comparative example has smaller crystal particles. Crystal particles in the early stages of growth. Since the crystal particles on the inner surface of the cylinder of the cylindrical sintered body in this comparative example are in the initial stage of growth, the crystal particles are small, uneven, and lack smoothness.

Although the details will be described in the manufacturing method, the above-mentioned cylindrical sintered body can be obtained by supplying oxygen to the cylindrical molded body along the cylindrical axis direction and sintering it.

2 is a cross-sectional view showing an example of the structure of the assembled cylindrical sputtering target according to the embodiment of the present invention. As shown in FIG. 2, in the assembled cylindrical sputtering target 100, a cylindrical base material 130 is arranged in the hollow inside the cylinder of the cylindrical sintered body 110 shown in FIG. 1. The cylindrical base material 130 and the cylindrical sintered body 110 are installed by the brazing material 140, and the adjacent cylindrical sintered body 110 is arranged through the space 120.

The material of the cylindrical substrate 130 can be made of a metal material with sufficient conductivity to bias the target and high thermal conductivity, so as to efficiently escape electrons or ions from hitting the target during sputtering. The heat generated. Specifically, copper (Cu), titanium (Ti), alloys containing these elements, and stainless steel (SUS) can be used.

The material of the brazing material 140 can be a material that has sufficient adhesion and strength to maintain the cylindrical sintered body 110 on the cylindrical base 130, and this material can have conductivity and high conductivity like the cylindrical base 130. Thermal conductivity. However, the thermal conductivity of the material of the brazing material 140 may also be lower than the thermal conductivity of the material of the cylindrical base 130. Moreover, the conductivity of the material of the brazing material 140 may also be lower than the conductivity of the material of the cylindrical base 130. The brazing material 140 can use, for example, indium (In), tin (Sn), and alloys containing these elements.

As described above, according to the sputtering target of this embodiment, by setting the length and relative density of the cylindrical sintered body within the above-mentioned ranges, the mechanical strength of the cylindrical sintered body can be improved, and it can be obtained The effect of reducing impurities in the thin film using the cylindrical sintered body and increasing the film density. Furthermore, by setting the relative density difference in and between solids of the cylindrical sintered body within the above ranges, it is possible to suppress the distortion of the electric field in the divided sputtering target with a plurality of cylindrical sintered bodies. . Therefore, stable discharge characteristics can be obtained during sputtering, and a thin film with extremely high in-plane uniformity can be formed on a large substrate whose size exceeds a single cylindrical sintered body. Furthermore, by setting the states of the inner surface of the cylinder and the outer surface of the cylinder of the cylindrical sintered body in the above ranges respectively, it is possible to stabilize the overall life span of the cylindrical sintered body in the split sputtering target. To maintain quality. That is, the characteristics of the target will not change during the continuous use of the target, and the nodules or particles caused by poor density can be suppressed.

The method of manufacturing the cylindrical sintered body will be described below.

Next, the method for manufacturing the cylindrical sintered body of the cylindrical sputtering target of the present invention will be described in detail using FIG. 3. FIG. 3 shows a flowchart of a method of manufacturing a cylindrical sintered body according to an embodiment of the present invention. Although the manufacturing method of the ITO sintered body is illustrated in FIG. 3, the material of the sintered body is not limited to ITO, and other oxide metal sintered bodies such as IGZO can also be used.

First, prepare the raw materials. As the raw material for mixing, for example, metal elements contained in oxides or alloys can be used. The raw material can be powdered, and the raw material can be appropriately selected according to the composition of the target sputtering target. For example, in the case of ITO, prepare indium oxide powder and tin oxide powder (steps S301 and S302). The purity of these raw materials is usually 2N (99% by mass) or more, may also be 3N (99.9% by mass) or more, or more than 4N (99.99% by mass). Since the cylindrical sintered body contains a large amount of impurities when the purity is less than 2N, problems such as difficulty in obtaining the expected material properties (such as reduced permeability, increased resistance of the film, local foreign matter content, and particle generation due to arc phenomenon) ).

Next, these raw material powders are crushed and mixed (step S303). The pulverization and mixing of the raw material powder can be dry-processed using zirconia, alumina, nylon resin and other spheres or beads, and can also be agitated and ground using the above-mentioned spheres or beads. Wet method is carried out by means of a rotary grinder, a medium-free container rotary grinder, a mechanical stirring grinder, and an air flow grinder. Generally speaking, since the pulverization and mixing ability of the wet method is better than that of the dry method, the wet method can be used here for mixing.

Although there is no particular limitation on the composition of the raw materials, the composition ratio of the target sputtering target can be adjusted appropriately.

Here, if a raw material powder with a fine particle size is used, the sintered body can be densified. Although the pulverization conditions can be strengthened to obtain fine powder, if this is the case, the mixing amount of the medium (zirconia, etc.) used in the pulverization will increase, and the concentration of impurities in the product may increase. In this way, it is necessary to observe the high density of the sintered body and the balance of the impurity concentration in the product while setting the conditions during the pulverization to an appropriate range.

Next, the slurry of raw material powder is dried for granulation (step S304). At this time, the slurry can also be rapidly dried using a rapid drying granulation method. For rapid drying and granulation, spray dryer can be used, and the temperature and air volume of hot air can be adjusted. Since the difference in the specific gravity of the raw material powder will cause the sedimentation rate to be different, the rapid drying granulation method can suppress the separation of the indium oxide powder and the tin oxide powder. With such a granulation method, the ratio of the formula ingredients can be made uniform, and the handling of the raw material powder can be improved. In addition, bisque treatment can also be carried out before and after granulation.

Next, the mixture obtained by the above-mentioned mixing and granulation process (after the unbaking process when the unbaked process is installed) is press-formed to form a cylindrical shaped body (step S305). Through this process, it can be formed into the appropriate shape of the target sputtering target. The length of the cylindrical shaped body along the cylindrical axis direction can be 600 mm or more. Although the molding process can be, for example, mold molding, casting molding, injection molding, etc., in order to obtain a complex shape such as a cylindrical shape, the molding can be performed by cold equalizing pressure (CIP). When molding by CIP, first fill the rubber mold with raw powder weighed with a specified weight. At this time, by shaking and tapping the rubber mold while filling, it is possible to avoid the uneven filling of the raw material powder in the mold or the generation of voids. The pressure during CIP molding can be above 100 MPa and below 200 MPa. By adjusting the pressure during molding as described above, in this embodiment, it is possible to form a cylindrical shaped body having a relative density of 54.5% or more and 58.0% or less. What's more, when the pressure during CIP molding is adjusted to 150 MPa or more and 180 MPa or less, a cylindrical shaped body with a relative density of 55.0% or more and 57.5% or less can be obtained.

Next, the cylindrical molded body obtained in the molding process is sintered (step S306). Here, the method for forming the molded body of the sintered cylinder will be described in detail using FIGS. 4 to 6. 4 is a perspective view of the process of forming a sintered cylinder into a molded body in a method for manufacturing a cylindrical sintered body of an embodiment of the present invention. FIG. 5 is a cross-sectional view of the process of forming a sintered cylinder into a molded body in a method of manufacturing a cylindrical sintered body according to an embodiment of the present invention. In addition, FIG. 6 is a plan view of the process of sintering a cylinder to form a molded body in the method of manufacturing a cylindrical sintered body of the embodiment of the present invention.

First, as shown in FIG. 4, in a state where the cylinder axis direction of the cylindrical shaped body 111 is slightly perpendicular to the flat sintering table 200, the cylinder will be obtained in the forming process of step S305 The molded body 111 is arranged on the sintering table 200. However, as long as the cylindrical molded body 111 can be stably arranged on the sintering table 200, it is not limited to this. For example, the cylindrical shaped body 111 may also be arranged on the sintering table 200 in an inclined state. In addition, although omitted in FIG. 4, when the cylindrical molded body 111 is sintered, a spacer may be arranged between the cylindrical molded body 111 and the sintering table 200. In this case, the spacer may also be arranged to contact the bottom surface 150 with an area smaller than the bottom surface 150 of the cylindrical shaped body 111. By arranging the spacers, even if the volume of the cylindrical shaped body 111 is reduced in the sintering process, the friction coefficient due to movement can be suppressed. Therefore, the internal stress generated in the sintered cylindrical sintered body can be suppressed.

As shown in FIGS. 5 and 6, the cylindrical molded body 111 obtained in the molding process of step S305 is arranged on the sintering table 200 provided in the chamber 300. The oxygen element supply port 230 provided in the plate-shaped sintering table 200 is arranged at the center of the cylinder, and the cylinder is sintered in this state to form the molded body 111. Considering that the cylindrical shaped body 111 may be shrunk due to the sintering process, the oxygen element supply port 230 may be smaller than the inner circumference of the cylindrical shaped body 111 and can supply oxygen to the inner surface of the cylinder. Furthermore, the oxygen element supply port 230 is arranged to supply the oxygen element from the downward direction of the cylindrical axis direction of the cylindrical shaped body 111 toward the upward direction. The opening provided in the sintering table 200 may only be the oxygen element supply port 230. A single oxygen element supply port 230 may be directly connected to a single pipe 240 for supplying oxygen element. The pipeline 240 is connected to the oxygen element supply port 230 from outside the chamber 300 via a controller, a valve, etc., for example. That is, the oxygen element supplied from the pipe 240 will not be exposed from other areas of the sintering table 200, and the oxygen element supply port 230 selectively supplies oxygen to the inner surface of the cylinder. With such a configuration, the amount of oxygen element supplied from the oxygen element supply port 230 can be appropriately adjusted according to the length and thickness of the cylindrical shaped body 111 along the cylindrical axis direction and the size of the internal space of the cylinder. For example, the longer the length of the cylinder axis, the more oxygen can be supplied from the oxygen supply port 230. However, it is not limited to this. For example, when the thickness of the cylindrical shaped body 111 is thick, the amount of oxygen element supplied from the oxygen element supply port 230 may be greater. In addition, for example, when the inner diameter of the cylindrical sintered body is large or the internal space of the cylinder is large, the amount of oxygen element supplied from the oxygen element supply port 230 may be large.

The upper limit of the amount of oxygen element supplied from the oxygen element supply port 230 is not particularly limited, but may be 150 L/min or less. When a large amount of oxygen is supplied through a single oxygen supply port 230, due to the cooling effect of oxygen, the cylindrical sintered body during sintering may be deformed or broken or the density of the sintered cylindrical sintered body may occur Decrease and other issues. Therefore, elements such as baffles may also be arranged from the oxygen element supply port 230 in the traveling direction of the oxygen element. The oxygen element supplied from the oxygen element supply port 230 can also diffuse in the internal space of the cylinder because it hits the baffle and other elements. Furthermore, the oxygen element supplied from the oxygen element supply port 230 may also be preheated in a cycle such as a pipeline and then supplied.

When oxygen is supplied to the hollow part inside the cylinder in an air atmosphere, since oxygen is heavier than nitrogen, it can be gradually filled with oxygen from the bottom of the cylinder axis. Therefore, it is possible to supply a uniform oxygen element to the inner surface of the cylinder of the cylindrical molded body during sintering. When the oxygen element fills the inner hollow part of the cylinder-forming body, the oxygen element further supplied can flow out from the upper part of the cylinder-forming body to the outside of the cylinder through the inner hollow part of the cylinder. The outflowing oxygen element can flow downward in the ceiling part of the chamber 300, and a circulating flow of oxygen element is generated in the chamber 300. Therefore, the oxygen concentration in the chamber 300 can also be made uniform. In addition, oxygen can also be supplied from the wall of the chamber 300 to the outside of the cylinder. In this case, by separately adjusting the oxygen supply amount to the inner hollow part of the cylinder and the oxygen element supply amount to the outer side of the cylinder, the sintering cylinder can be formed into the cylinder inner and outer sides of the body. The oxygen concentration is uniform.

Here, although FIG. 4 illustrates a method of supplying oxygen to the hollow portion inside the cylinder of the cylindrical molded body 111 from below, it is not limited to this method. For example, the oxygen element may be supplied from below or above the cylinder axis direction. By supplying oxygen in the direction of the cylindrical axis of the cylindrical shaped body 111, the concentration of oxygen can be maintained uniformly in the direction of the cylindrical axis during sintering.

In addition, although FIG. 4 illustrates a method of supplying oxygen from the oxygen element supply port 230 that is solely arranged in the center of the cylinder of the cylindrical shaped body 111, it is not limited to this method. As long as the oxygen element can be uniformly supplied to the hollow portion inside the cylinder, the oxygen element supply port 230 is not limited to the center of the cylinder. The number of oxygen element supply ports 230 may also be multiple. Furthermore, not only the oxygen element is supplied to the inside of the cylinder, but also the oxygen element is supplied to the outside of the cylinder. At this time, the oxygen element supply ports 230 can be independent of each other and can control the oxygen element supply amount, and can be directly connected to the pipeline 240 for supplying oxygen element. Thereby, according to the length and thickness of the cylindrical shaped body 111 in the direction of the cylindrical axis, the size of the internal space of the cylinder, and the position of the oxygen element supply port 230 relative to the cylindrical shaped body 111, it is possible to appropriately adjust the oxygen The amount of oxygen element supplied by the element supply port 230.

Generally speaking, in the sintering of ITO, it is necessary to perform sintering in an oxygen element gas environment to increase the density of the sintered body. Even if the sintering is carried out in an oxygen element gas environment, in the process of forming a cylindrical body 111 with a sintering length of 600 mm or more, the gas convection in the hollow inside the cylinder is insufficient, and the hollow inside the cylinder may occur Insufficient oxygen. If there is insufficient oxygen in the hollow part inside the cylinder, the cylindrical sintered body may be deformed or cracked during sintering, or the density of the sintered cylindrical sintered body may decrease, and the cylindrical sintered body may move along the cylinder axis. Problems such as the increase in the relative density difference and the increase in the size or number of holes observed on the inner surface of the cylinder of the cylindrical sintered body. In order to prevent the influence caused by the lack of oxygen in the inner hollow part, in the present embodiment, when the sintered cylindrical molded body 111 is configured as described above, the oxygen element supply port 230 is used for the cylindrical molded body 111 The inner hollow part of the cylinder is supplied with oxygen element, and the inner hollow part of the cylinder formed body 111 of 600 mm or more can be evenly filled with oxygen element. Furthermore, by combining the oxygen element supply to the inner hollow part of the cylinder, that is, the oxygen element supply to the outer side of the cylinder, the oxygen element concentration on the inner surface and outer surface of the cylinder formed body 111 during sintering can be made Evenly. As a result, it is possible to prevent the cylindrical sintered body from deforming and cracking during sintering. Moreover, the density of the cylindrical sintered body after sintering can be increased. Furthermore, the relative density difference in the solid of the cylindrical sintered body along the cylindrical axis direction can be reduced. It can also reduce the size and number of holes on the inner side of the cylinder.

The following will return to FIG. 3 to continue the description of the method of manufacturing the cylindrical sintered body. In the details described above, the sintering of step S306 can be performed using an electric furnace, hot equalization pressure (HIP), or microwave sintering. Although the sintering conditions can be appropriately selected according to the composition of the sintered body, for example, in the case of ITO containing 10 wt·% of SnO ₂ , the temperature can be 1500 degrees Celsius or more and 1600 degrees Celsius in an oxygen element gas environment for 10 Sintering is carried out under the conditions of more than 20 hours and less than 20 hours. When the sintering temperature is less than 1500 degrees Celsius, the density of the target may decrease. On the other hand, if it exceeds 1600 degrees Celsius, the damage to the electric furnace or furnace materials will increase and timely maintenance is necessary, which may result in a significant decrease in work efficiency. Moreover, if the sintering time is less than 10 hours, the density of the target may decrease. If it is longer than 20 hours, the maintenance time in the sintering process will be prolonged, and the operating efficiency of the electric furnace may be deteriorated. Moreover, it may also increase the consumption of oxygen element gas used in the sintering process and increase the electricity used to operate the electric furnace. In addition, the pressure during sintering can be atmospheric pressure, or can be a reduced-pressure gas environment or a pressurized gas environment.

Here, when an electric furnace is used for sintering, it is possible to suppress the occurrence of cracks by adjusting the heating rate and cooling rate of the sintering. Specifically, the heating rate of the electric furnace during sintering can be less than 300 degrees Celsius per hour, and can even be less than 180 degrees Celsius per hour. In addition, the cooling rate of the electric furnace during sintering can be below 600 degrees Celsius per hour. Among them, it is also possible to adjust the temperature increase rate or the temperature decrease rate step by step.

Although the cylindrical shaped body shrinks due to the sintering process, the temperature in the furnace is uniform before all the materials enter the temperature range where the heat shrinks together, and the temperature is maintained during the heating process to eliminate the temperature in the furnace Uneven, so the entire sintered body set in the furnace can shrink uniformly. Therefore, by setting the reaching temperature and the holding time to appropriate conditions for various materials, a stable sintered body density can be obtained. By sintering a cylindrical body with a length of 600 mm or more in the direction of the cylindrical axis, a cylindrical sintered body with a length of about 470 mm or more in the direction of the cylindrical axis can be obtained.

Next, use machining machines such as surface grinders, cylindrical grinders, lathes, cutting machines, machining centers, etc., to machine the formed cylindrical sintered body into the expected cylindrical shape Shape (step S307). The machining performed here is to process the cylindrical sintered body into a shape suitable for installation in a sputtering device, and process it to have the desired surface roughness. Here, in order to obtain flatness such as abnormal discharge without electric field concentration during sputtering, the average surface roughness (Ra) of the cylindrical sintered body can be set to 0.5 μm or less. Through the above process, a cylindrical sintered body with high density and high homogeneity can be obtained.

Next, the machined cylindrical sintered body is joined to the base material (step S308). Especially in the case of a cylindrical sputtering target, the cylindrical sintered body is joined to a cylindrical substrate called a backing tube through a brazing material used as an adhesive. Through the above process, a cylindrical sputtering target using the cylindrical sintered body can be obtained.

As described above, according to the manufacturing method of the cylindrical sputtering target of the implementation mode, in the sintering process, by supplying oxygen to the hollow portion inside the cylinder of the cylindrical body, it is possible to prevent rounding during sintering. Deformation and fracture of cylindrical sintered body. Moreover, the density of the cylindrical sintered body after sintering can be increased. Furthermore, the relative density difference of the sintered cylindrical sintered body along the cylindrical axis direction can be reduced. It can also reduce the size of the holes observed on the inner surface of the cylinder of the sintered cylindrical sintered body. In addition, the number of holes observed on the inner surface of the cylinder of the sintered cylindrical sintered body can be reduced. The cylindrical sintered body and cylindrical sputtering target that can be provided by this can have high homogeneity in and between solids.

The modification 1 will be described below.

The method of sintering the cylindrical sintered body of Modification 1 of the embodiment of the present invention will be explained using FIG. 7.

FIG. 7 is a plan view of the process of sintering the cylindrical sintered body in the manufacturing method of the cylindrical sintered body in the modification 1 of the embodiment of the present invention. In the process of forming the sintered cylinder 111 shown in FIG. 7, sixteen oxygen element supply ports 230 are arranged. At this time, the oxygen element supply ports 230 can be independent of each other and can control the oxygen element supply amount, and can be directly connected to the pipeline 240 for supplying oxygen element. Thereby, according to the length and thickness of the cylindrical shaped body 111 in the direction of the cylindrical axis, the size of the internal space of the cylinder, and the position of the oxygen element supply port 230 relative to the cylindrical shaped body 111, it is possible to appropriately adjust the oxygen The amount of oxygen element supplied by the element supply port 230.

In FIG. 7, the eight pairs of oxygen element supply ports 230 sandwich the wall of the cylindrical shaped body 111 and are evenly arranged. In other words, eight oxygen element supply ports 230 are respectively arranged along the inner surface and outer surface of the cylindrical shaped body 111. In FIG. 7, the eight oxygen element supply ports 230a are located inside the cylinder of the cylindrical shaped body 111, and the eight oxygen element supply ports 230b are located outside the cylinder of the cylindrical shaped body 111, thereby configuring the cylinder to form The body 111 (hereinafter referred to as the oxygen element supply port 230 when the oxygen element supply port 230a and the oxygen element supply port 230b are not distinguished). However, it is not limited to this. As long as the cylindrical shaped body 111 can be stably arranged on the sintering table 200, the number, size, and arrangement of the oxygen element supply ports 230 are not limited. In addition, the oxygen element supply port 230 is not only arranged inside the cylinder of the cylindrical shaped body 111, but may also be arranged outside the drum. In other words, not only the oxygen element is supplied to the inner surface of the cylinder, but also the oxygen element is supplied to the outer surface of the cylinder.

For example, in the case where the length of the cylindrical shaped body 111 is relatively long, the oxygen supply amount from the oxygen element supply port 230a located on the inner side of the cylinder with poor convection is greater, and the oxygen element is supplied from the outer side of the cylinder The oxygen supply amount of the port 230b is small, thereby adjusting the oxygen concentration on the inner and outer sides of the cylinder to be uniform. Moreover, the oxygen element may be supplied only from the oxygen element supply port 230a located inside the cylinder. The amount of oxygen supplied by each oxygen element supply port 230a may be, for example, one-eighth of the amount of oxygen supplied from a single oxygen element supply port 230 in the embodiment of the present invention. In addition, the amount of oxygen element supplied by each oxygen element supply port 230a may not be uniform, or may be different. That is, the total amount of oxygen element supplied from the plurality of oxygen element supply ports 230a may also be the amount of oxygen element supplied from a single oxygen element supply port 230 in the embodiment of the present invention. In addition, the longer the length in the cylinder axis direction, the greater the total amount of oxygen elements supplied from the oxygen element supply port 230a. However, it is not limited to this. For example, when the thickness of the cylindrical shaped body 111 is thick, the amount of oxygen element supplied from the oxygen element supply port 230 may be greater. In addition, for example, in the case where the inner diameter of the cylindrical sintered body is large or the internal space of the cylinder is large, the total amount of oxygen elements supplied from the oxygen element supply port 230a may be large. In addition, for example, in the case where the inner diameter of the cylindrical sintered body is large or the internal space of the cylinder is large, the total amount of oxygen elements supplied from the oxygen element supply port 230a may be large.

The upper limit of the amount of oxygen element supplied from the oxygen element supply port 230 is not particularly limited, but may be 150 L/min or less. By supplying the oxygen element through the plurality of oxygen element supply ports 230a, the supply amount of the oxygen element can be dispersed, and the gas convection in the hollow inside the cylinder can be controlled. In addition, it is also possible to suppress the deformation and cracking of the cylindrical sintered body during sintering due to the cooling effect of the oxygen element, or the decrease in the density of the cylindrical sintered body after sintering. Therefore, the oxygen element supplied from the plurality of oxygen element supply ports 230a can also diffuse in the inner space of the cylinder through elements such as baffles. Furthermore, the oxygen element supplied from the oxygen element supply port 230 may also be preheated in a cycle such as a pipeline and then supplied.

Generally speaking, in the sintering of ITO, it is necessary to perform sintering in an oxygen element gas environment to increase the density of the sintered body. Even if the sintering is carried out in an oxygen element gas environment, in the process of forming a cylindrical body 111 with a sintering length of 600 mm or more, the gas convection in the hollow inside the cylinder is insufficient, and the hollow inside the cylinder may occur Insufficient oxygen. If there is insufficient oxygen in the hollow part inside the cylinder, the cylindrical sintered body may be deformed or cracked during sintering, or the density of the sintered cylindrical sintered body may decrease, and the cylindrical sintered body may move along the cylinder axis. Problems such as the increase in the relative density difference and the increase in the size or number of holes observed on the inner surface of the cylinder of the cylindrical sintered body. In order to prevent the influence caused by the lack of oxygen in the cylinder, in this embodiment, the oxygen supply from the oxygen supply port 230a located inside the cylinder is larger, and the oxygen supply from the outside of the cylinder The oxygen element supply amount of the element supply port 230b is small, so that the oxygen element concentration on the inner and outer sides of the cylinder is finally uniform. By further increasing the oxygen element supply amount from the oxygen element supply port 230a located inside the cylinder, it can also be adjusted so that the oxygen element concentration on the inner side of the cylinder is finally greater than the oxygen element concentration on the outer side of the cylinder. Furthermore, it may be adjusted so that oxygen is only supplied from the oxygen element supply port 230a located inside the cylinder, and the oxygen element is not supplied from the oxygen element supply port 230b located outside the cylinder. Each oxygen element supply port 230 can be independent of each other and can control the oxygen element supply amount, and can be directly connected to the pipeline 240 for supplying oxygen element. By supplying the oxygen element from the plurality of oxygen element supply ports 230a, the oxygen element can be more uniformly supplied to the inner surface of the cylinder. As a result of this, it is possible to adjust the oxygen concentration on the inner and outer surfaces of the cylindrical shaped body during sintering, and prevent deformation and cracking of the cylindrical sintered body during sintering. Moreover, the density of the cylindrical sintered body after sintering can be increased. Furthermore, the relative density difference of the sintered cylindrical sintered body along the cylindrical axis direction can be reduced. It can also reduce the equivalent circle diameter of the hole area observed on the inner surface of the cylinder of the sintered cylindrical sintered body. In addition, the number of holes observed on the inner surface of the cylinder of the sintered cylindrical sintered body can be reduced.

The modification 2 will be described below.

The sintering method of the cylindrical sintered body in the modification 2 of the embodiment of the present invention will be explained using FIG. 8. In this modified example, since it is the same as the embodiment of the present invention except for the baffle 260, detailed description thereof will be omitted.

8 is a cross-sectional view of the process of sintering a cylinder to form a molded body in the method of manufacturing a cylindrical sintered body of Modification 2 of the embodiment of the present invention. In the process of forming the sintered cylinder 111 shown in FIG. 8, a single oxygen element supply port 230 is arranged. The oxygen element supply port 230 can independently control the oxygen element supply amount, and can be directly connected to the pipeline 240 for supplying oxygen element. The baffle plate 260 is arranged from the oxygen element supply port 230 in the traveling direction of the oxygen element. In this modification, the baffle 260 has a cap shape surrounding the oxygen element supply port 230. The baffle 260 has a plurality of openings 280 on the side wall of the cap shape. Therefore, the oxygen element supplied from the oxygen element supply port 230 hits the inner ceiling portion of the baffle 260 and flows out from the openings 280 of the baffle 260 in a diffused state. The oxygen element flowing out of the openings 280 of the baffle plate 260 can gradually fill the inner hollow part of the cylindrical shaped body from below the cylindrical axis direction, and rise along the cylindrical axis direction. However, the shape of the baffle 260 is not limited to this, and the shape of the baffle 260 is such that the oxygen element supplied from the oxygen element supply port 230 can diffuse in the inner space of the cylinder. For example, as viewed from the traveling direction of the oxygen element, the baffle 260 may overlap at least a part of the oxygen element supply port 230. Originally, when a large amount of oxygen is supplied from a single oxygen element supply port 230, problems such as deformation and cracking of the cylindrical sintered body during sintering or a decrease in the density of the cylindrical sintered body after sintering may occur due to the cooling effect of the oxygen element. . With Modification 2, the above-mentioned problems can be suppressed.

However, the present invention is not limited to the above-mentioned embodiments, and can be appropriately changed without departing from the gist.

The production of the cylindrical sintered body of the embodiment will be described below.

The embodiment 1 will be explained below.

In Example 1, a method for manufacturing a cylindrical ITO target material (cylindrical sintered body) will be explained. First, prepare 4N indium oxide with a BET (Brunauer Emmet and Teller's equation) specific surface area of 4.0 m ² /g or more and 6.0 m ² /g and a BET specific surface area of 4.0 m ² /g or more and 5.7 m ² /g The following 4N tin oxide is used as raw material powder. Here, the BET specific surface area means the surface area obtained by the BET method. The BET method is a gas adsorption method in which gas molecules such as nitrogen, argon, krypton, and carbon monoxide are adsorbed on solid particles, and the specific surface area of the solid particles is measured from the amount of the adsorbed gas molecules. Here, 90% by mass of indium oxide and 10% by mass of tin oxide are used as raw materials. Next, use a wet ball mill to pulverize and mix these raw material powders. Here, zirconia spheres are used as the crushing medium. The mixed slurry is rapidly dried and granulated by a spray dryer.

Next, CIP molding is used to shape the mixture obtained in the above-mentioned pelletizing process into a cylindrical shape. The pressure when forming with CIP is 176MPa.

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

The outer diameter (diameter) of the cylinder = 194.0 mm.

The inner diameter (diameter) of the cylinder = 158.7 mm.

The thickness of the cylinder = 17.65 mm.

The length of the cylinder axis = 600 mm.

Next, an electric furnace is used to sinter the cylindrical molded body obtained by CIP. The sintering conditions are as follows.

Heating rate = 300 degrees Celsius/hour.

High temperature maintenance temperature = 1560 degrees Celsius.

High temperature maintenance time = 20 hours.

Gas environment during sintering = oxygen gas environment.

Pressure during sintering = atmospheric pressure.

The oxygen element introduced into the hollow inside the cylinder = 50 L/min.

The oxygen element introduced to the outside of the cylinder=0 L/min.

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

The outer diameter (diameter) of the cylinder = 155.2 mm.

The inner diameter (diameter) of the cylinder = 127.0 mm.

The thickness of the cylinder = 14.1 mm.

The length of the cylinder axis = 478 mm.

Sintered body density = 7.134 g/cm ³ .

The relative density of the sintered body = 99.68%.

The bulk impedance value of the sintered body = 0.11 mΩ·cm.

The embodiment 2 will be explained below.

In Example 2, a description will be given of a cylindrical sintered body formed by a sintered cylinder whose length in the axial direction is greater than that of the cylindrical molded body of Example 1. Since the molding process of the cylindrical molded body is the same as that of Embodiment 1, the description thereof is omitted.

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

The outer diameter (diameter) of the cylinder = 193.8 mm.

The inner diameter (diameter) of the cylinder = 158.2 mm.

The thickness of the cylinder = 17.8 mm.

The length of the cylinder axis = 1200 mm.

Next, an electric furnace is used to sinter the cylinder to form a molded body. The sintering conditions of Example 2 are the same as those of Example 1 except for the oxygen element parameters introduced into the hollow portion inside the cylinder, so the description is omitted.

Oxygen element introduced into the hollow inside the cylinder = 100 L/min.

The oxygen element introduced to the outside of the cylinder=0 L/min.

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

The outer diameter (diameter) of the cylinder = 155.0 mm.

The inner diameter (diameter) of the cylinder = 126.6 mm.

The thickness of the cylinder = 14.2 mm.

The length of the cylinder axis = 948 mm.

Sintered body density = 7.132 g/cm ³ .

The relative density of the sintered body = 99.65%.

The block resistance value of the sintered body = 0.12 mΩ·cm.

The embodiment 3 will be explained below.

In Example 3, a description will be given of a cylindrical sintered body having a length in the axial direction of the sintering cylinder that is greater than that of the cylindrical shaped bodies of Examples 1 and 2. Since the molding process of the cylindrical molded body is the same as that of Embodiment 1, the description thereof is omitted.

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

The outer diameter (diameter) of the cylinder = 194.2 mm.

Cylinder inner diameter (diameter) = 158.5 mm.

The thickness of the cylinder = 17.85 mm.

The length of the cylinder axis = 1755 mm.

Next, an electric furnace is used to sinter the cylinder to form a molded body. The sintering conditions of Example 3 are the same as those of Example 1 except for the oxygen element parameters introduced into the hollow portion inside the cylinder, so the description is omitted.

The oxygen element introduced into the hollow inside the cylinder = 150 L/min.

The oxygen element introduced to the outside of the cylinder=0 L/min.

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

The outer diameter (diameter) of the cylinder = 155.4 mm.

The inner diameter (diameter) of the cylinder = 126.8 mm.

The thickness of the cylinder = 14.3 mm.

The length of the cylinder axis = 1386 mm.

Sintered body density = 7.130 g/cm ³ .

The relative density of the sintered body = 99.62%.

The block resistance value of the sintered body = 0.12 mΩ·cm.

Next, a comparative example with respect to the cylindrical formed body and the cylindrical sintered body shown in the above-mentioned Examples 1 to 3 will be described below. The following comparative examples are different from the examples. In the comparative examples, a description will be given of a cylindrical sintered body that is sintered under conditions that do not introduce oxygen to the inner hollow portion of the cylindrical molded body. Among them, in the comparative example, the oxygen element is not introduced into the inner hollow part of the cylindrical molded body, and the sintering is performed under the condition that the oxygen element is introduced to the outside of the cylindrical molded body. Since the molding process of the cylindrical molded body is the same as that of Embodiment 1, the description thereof is omitted.

The comparative example 1 will be described below.

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

The outer diameter (diameter) of the cylinder = 194.9 mm.

Cylinder inner diameter (diameter) = 159.0 mm.

The thickness of the cylinder = 17.95 mm.

The length of the cylinder axis = 480 mm.

Next, an electric furnace is used to sinter the cylinder to form a molded body. The sintering conditions of Comparative Example 1 are the same as those of Example 1 except for the oxygen element parameters introduced into the cylindrical molded body, so the description is omitted.

The oxygen element introduced into the hollow inside the cylinder=0 L/min.

The oxygen element introduced to the outside of the cylinder = 100 L/min.

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

The outer diameter (diameter) of the cylinder = 155.9 mm.

The inner diameter (diameter) of the cylinder = 127.2 mm.

The thickness of the cylinder = 14.35 mm.

The length of the cylinder axis = 385 mm.

The density of the sintered body = 7.133 g/cm ³ .

The relative density of the sintered body = 99.66%.

The block resistance value of the sintered body = 0.11 mΩ·cm.

The comparative example 2 will be described below.

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

The outer diameter (diameter) of the cylinder = 193.5 mm.

The inner diameter (diameter) of the cylinder = 158.2 mm.

The thickness of the cylinder = 17.65 mm.

The length of the cylinder axis = 600 mm.

Next, an electric furnace is used to sinter the cylinder to form a molded body. The sintering conditions of Comparative Example 2 are the same as those of Example 1 except for the oxygen element parameters introduced into the cylindrical molded body, so the description is omitted.

The oxygen element introduced into the hollow inside the cylinder=0 L/min.

The oxygen element introduced to the outside of the cylinder = 100 L/min.

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

The outer diameter (diameter) of the cylinder = 156.7 mm.

The inner diameter (diameter) of the cylinder = 128.1 mm.

The thickness of the cylinder = 14.3 mm.

The length of the cylinder axis = 485 mm.

Density of sintered body=7.041 g/cm ³ .

The relative density of the sintered body = 98.38%.

The block resistance value of the sintered body = 0.12 mΩ·cm.

The comparative example 3 will be described below.

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

The outer diameter (diameter) of the cylinder = 194.1 mm.

The inner diameter (diameter) of the cylinder = 158.2 mm.

The thickness of the cylinder = 17.95 mm.

The length of the cylinder axis = 1200 mm.

Next, an electric furnace is used to sinter the cylinder to form a molded body. The sintering conditions of Comparative Example 3 are the same as those of Example 1 except for the oxygen element parameters introduced into the cylindrical molded body, so the description is omitted.

The oxygen element introduced into the hollow inside the cylinder=0 L/min.

The oxygen element introduced to the outside of the cylinder = 100 L/min.

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

The outer diameter (diameter) of the cylinder = 157.2 mm.

The inner diameter (diameter) of the cylinder = 128.1 mm.

The thickness of the cylinder = 14.55 mm.

The length of the cylinder axis = 957 mm.

Sintered body density = 7.038 g/cm ³ .

The relative density of the sintered body = 98.34%.

The block resistance value of the sintered body = 0.12 mΩ·cm.

Among them, in Comparative Example 3, the deformation due to sintering was confirmed.

The comparative example 4 will be described below.

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

The outer diameter (diameter) of the cylinder = 194.2 mm.

The inner diameter (diameter) of the cylinder = 158.4 mm.

The thickness of the cylinder = 17.9 mm.

The length of the cylinder axis = 1410 mm.

Next, an electric furnace is used to sinter the cylinder to form a molded body. The sintering conditions of Comparative Example 4 are the same as those of Example 1 except for the oxygen element parameters introduced into the cylindrical molded body, so the description is omitted.

The oxygen element introduced into the hollow inside the cylinder=0 L/min.

The oxygen element introduced to the outside of the cylinder = 100 L/min.

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

The outer diameter (diameter) of the cylinder = 155.3 mm.

Cylinder inner diameter (diameter) = 127.8 mm.

The thickness of the cylinder = 13.75 mm.

The length of the cylinder axis = 1145 mm.

Density of sintered body=7.042 g/cm ³ .

The relative density of the sintered body = 98.39%.

The block resistance value of the sintered body = 0.12 mΩ·cm.

The comparative example 5 will be described below.

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

The outer diameter (diameter) of the cylinder = 193.6 mm.

Cylinder inner diameter (diameter) = 158.3 mm.

The thickness of the cylinder = 17.65 mm.

The length of the cylinder axis = 1754 mm.

Next, an electric furnace is used to sinter the cylinder to form a molded body. The sintering conditions of Comparative Example 5 are the same as those of Example 1 except for the oxygen element parameters introduced into the cylindrical molded body, so the description is omitted.

The oxygen element introduced into the hollow inside the cylinder=0 L/min.

The oxygen element introduced to the outside of the cylinder = 100 L/min.

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

The outer diameter (diameter) of the cylinder = 157.8 mm.

Cylinder inner diameter (diameter) = 128.5 mm.

The thickness of the cylinder = 14.65 mm.

The length of the cylinder axis = 1394 mm.

Density of sintered body=7.044 g/cm ³ .

The relative density of the sintered body = 98.42%.

The block resistance value of the sintered body = 0.12 mΩ·cm.

The preparation of the measurement sample will be explained below.

For the cylindrical sintered bodies of the above-mentioned Examples 1 to 3 and Comparative Examples 1 to 5, measurement samples for evaluating the density and the internal deviation of the block resistance in the solid were prepared. As shown in Fig. 9, the cylindrical sintered body 110 is segmented at intervals of 150 mm from the direction of the cylinder axis to the upper side during sintering, and the central part of each cylinder axis is cut out with a width of 40-50 mm. Cylindrical measurement sample. It is 110-1 (150 mm), 110-25 (300 mm), 110-3 (450 mm) in order from the bottom of the cylinder shaft (names in the table below).

The evaluation of relative density will be described below.

With respect to the cylindrical sintered bodies of the above-mentioned Examples 1 to 3 and Comparative Examples 1 to 5 and respective measurement samples, the relative density thereof was evaluated. The Archimedes method is used to measure the density of the cylindrical sintered body and each sample. Calculate the relative density and relative density difference of the cylindrical sintered body and each measured sample based on the theoretical density. FIG. 10 shows the density, relative density, and maximum relative density difference in the cylindrical sintered body and each measured sample in Examples 1 to 3 and Comparative Examples 1 to 5 in Comparative Examples.

It can be seen from the results in Fig. 10 that compared to the cylindrical sintered bodies of Comparative Examples 2 to 5 in which oxygen elements were not introduced into the inner hollow portion of the cylindrical shaped body during sintering, oxygen elements were introduced during sintering The relative density of the cylindrical sintered bodies of Examples 1 to 3 to the inner hollow portion of the cylindrical shaped body was increased. In Comparative Example 1 in which the length of the cylinder axis direction is 470 mm or less, even if oxygen is not introduced into the inner hollow part of the cylinder formed body, the relative density is increased. Compared with the measurement samples of Comparative Example 2 to Comparative Example 5, the measurement samples of Example 1 to Example 3 can reduce their relative density differences. In Comparative Example 1 in which the length of the cylinder axis direction is 470 mm or less, even if oxygen is not introduced into the inner hollow portion of the cylinder formed body, the relative density difference can be reduced. Therefore, by supplying oxygen to the inner surface of the cylindrical body in the sintering process, the cylindrical body with a length of 1200 mm or more in the direction of the cylinder axis can also prevent deformation and cracking during sintering. problem.

The evaluation of the minimum oxygen supply amount will be described below.

According to the sintering method of the cylindrical shaped body in the above-mentioned Examples and Comparative Examples, the minimum oxygen element supply amount that can be obtained for a cylindrical sintered body with a density of 7.130 g/cm ³ or more is obtained. Specifically, the amount of oxygen introduced into the hollow part of the cylinder during sintering is changed in stages to obtain a cylindrical sintered body with a length of 390, 480, 950, 1200, or 1400 mm in the direction of the cylinder axis. The Archimedes method was used to measure the density of each cylindrical sintered body. In a cylindrical sintered body with a density of 7.130 g/cm ³ or more, the length of each cylinder axis is used as the difference, and the minimum oxygen element supply amount is the value of the minimum oxygen element introduced during sintering. Fig. 11 shows the relationship between the minimum oxygen element supply amount and the length of the cylindrical sintered body in the cylindrical axis direction.

As shown in Figure 11, when the length of the cylindrical sintered body in the cylindrical axis direction is 390 mm, even if oxygen is not introduced, a cylindrical sintered body with a density of 7.130 g/cm ³ or more can be obtained. In the case of forming a 480 mm cylindrical sintered body, the minimum oxygen element supply amount is 5 L/min or more. In the case of forming a 950 mm cylindrical sintered body, the minimum oxygen element supply amount is 20 L/min or more. In the case of forming a 1200 mm cylindrical sintered body, the minimum oxygen element supply amount is 30 L/min or more. In the case of forming a 1400 mm cylindrical sintered body, the minimum oxygen element supply amount is 35 L/min or more. From the results in Fig. 11, it can be seen that the longer the length in the cylinder axis direction, the greater the amount of oxygen required to obtain a cylindrical sintered body with a density of 7.130 g/cm ³ or more. The axial length of the cylindrical sintered body with a density of 7.130 g/cm ³ or more is set to X (mm), and the minimum oxygen supply amount supplied from the oxygen element supply port 230 is set to Y (L/min), and its ratio The relationship can be expressed by the following formula.

Y = 0.0345X-12.508.

The evaluation of the block impedance will be described below.

With respect to the cylindrical sintered bodies of the above-mentioned Examples 1 to 3 and Comparative Examples 1 to 5 and each measurement sample, the bulk impedance was evaluated. The four-probe method was used to measure the cylindrical sintered body and the bulk impedance value of each measured sample on the outer side of the cylinder. FIG. 12 shows the block impedance values of the cylindrical sintered body and each measured sample in Example 1 to Example 3 and Comparative Example 1 to Comparative Example 5.

It can be seen from the results in FIG. 12 that in the cylindrical sintered bodies of Examples 1 to 3 and Comparative Examples 1 to 5 and each measured sample, the resistance value of the block on the outer surface of the cylinder hardly changed. Since the outer surface of the cylinder is sufficiently supplied with oxygen, no matter it is an example where oxygen is introduced into the hollow part of the cylinder-forming body, or a comparative example where oxygen is not introduced into the hollow part of the cylinder. , Can be considered to have almost no effect on the impedance value of the block on the outer side of the cylinder.

The preparation of samples for electron microscope observation will be described below.

For the cylindrical sintered bodies of Examples 1 and 2 and Comparative Examples 2 and 3, samples for observation with an electron microscope were prepared. As shown in Figure 13, a cylindrical sample 110-4 with a width of 10 mm is cut from the cylindrical sintered body 110 along the central part of the cylindrical axis direction, from the cylindrical inner surface 110-4a and the cylindrical outer surface 110-4b Cut out the sample for electron microscope observation, and perform mirror polishing in a state of 0.5 mm polishing.

The observation by electron microscope will be explained below.

For the cylindrical sintered bodies of the above-mentioned Examples 1 and 2 and Comparative Examples 2 and 3, an electron microscope observation sample was used to observe the inner and outer sides of the cylinder of the cylindrical sintered body using an electron microscope (SEM). In each sample, the photographs observed with an electron microscope (SEM) under a field of view of 1000 times are shown in Figure 14 (inside the cylinder) and Figure 15 (outside the cylinder). In addition, in each sample, the photographs observed with an electron microscope (SEM) under a field of view of 2000 or 5000 times are shown in Figure 16 (inside the cylinder) and Figure 17 (outside the cylinder). In Figs. 14-17, the circle of the cylindrical sintered body of (a) Example 1, (b) Example 2, (c) Comparative Example 2, (d) Comparative Example 3 was observed using an electron microscope (SEM) Samples for electron microscope observation on the inner and outer sides of the tube.

Fig. 14 (a) and (b) are electron micrographs of the inner side of the cylindrical sintered body in Example 1 and Example 2. Fig. 15 (a) and (b) are electron micrographs of the cylindrical sintered outer surface of Example 1 and Example 2. (C) and (d) of Fig. 14 are electron micrographs of the inner surface of the cylindrical sintered body in Comparative Example 2 and Comparative Example 3. Figure 15 (c) and (d) are electron micrographs of the cylindrical sintered outer side of Comparative Example 2 and Comparative Example 3. As shown in Fig. 14 and Fig. 15, in Examples 1 and 2 in which oxygen is introduced into the hollow part of the cylinder inside the cylindrical body during sintering, the inner side of the cylindrical sintered body (Fig. 14(a)) And (b)) and the outer side (Figure 15 (a) and (b)) electron microscope photos did not observe significant differences. On the other hand, in Comparative Example 2 and Comparative Example 3 in which oxygen is not introduced into the hollow part of the cylindrical body during sintering, compared with the cylindrical sintered outer surface (Figure 15(c) and (D)) A large number of large holes (black irregularities in the photo) are observed in the electron microscope photos of the cylindrical sintered inner surface (Figure 14 (c) and (d)). In Comparative Example 2 and Comparative Example 3, a large number of irregular granular (crystalline grain) holes were observed on the inner surface of the cylinder of the cylindrical sintered body. The pores observed on the inner surface of the cylinder of the cylindrical sintered body in Comparative Example 2 and Comparative Example 3 were mainly observed at the crystal grain boundary.

Next, in order to observe the state of the crystalline particles, especially in the comparative example, the area with large holes is not observed in (c) and (d) of Fig. 14 under the field of view of 2000 or 5000 times. Figure 16 (a) and (b) are electron micrographs of the inner side of the cylindrical sintered body in Example 1 and Example 2. Fig. 17 (a) and (b) are electron micrographs of the cylindrical sintered outer surface of Example 1 and Example 2. (C) and (d) of Fig. 16 are electron micrographs of the inner surface of the cylindrical sintered body in Comparative Example 2 and Comparative Example 3. Figure 17 (c) and (d) are electron micrographs of the cylindrical sintered outer side surface of Comparative Example 2 and Comparative Example 3. As shown in Fig. 16 and Fig. 17, in Examples 1 and 2 where oxygen is introduced into the hollow part of the cylinder inside the cylindrical body during sintering, the inner side of the cylindrical sintered body (Fig. 16(a)) And (b)) and the outer side (Figure 17 (a) and (b)) electron micrographs did not observe significant differences, large-scale growth of crystal particles. During sintering, no oxygen element was introduced into the hollow part of the cylindrical inner side of the cylindrical shaped body, and the length in the cylindrical axis direction of Comparative Example 2 was shorter than that of Comparative Example 3. In Comparative Example 2, the inner surface of the cylindrical sintered body ( The electron micrographs of Fig. 16(c)) and the outer surface (Fig. 17(c)) did not show any significant difference, and the crystal particles grew in large size. On the other hand, during sintering, no oxygen element was introduced into the hollow part of the cylinder inside the cylinder, and the length in the cylinder axis direction of Comparative Example 3 was greater than that of Comparative Example 2. In Comparative Example 3, compared to The electron micrographs of the cylindrical sintered outer side surface (Figure 17(d)) and the cylindrical sintered inner side surface (Figure 16(d)) showed small-scale growth of crystalline particles in the early stage of growth. In Comparative Example 3, since the crystal particles on the inner surface of the cylindrical sintered body are in the initial stage of growth, the crystal particles are small, uneven, and lack smoothness.

Small irregular granular (bubble-like) holes (such as the hole in the upper left of Figure 17 (b)) were observed on the inner and outer sides of the cylindrical sintered body of Example 1 and Example 2. In the cylindrical sintered bodies of Comparative Example 2 and Comparative Example 3, similarly small irregular grain-shaped (bubble-shaped) holes were also observed on the outer surface of the cylinder. Whether observing the crystal grain boundary or the inside of the crystal, the inner surface of the cylindrical sintered body of Example 1 and Example 2 and the cylindrical sintered body of Comparative Example 2 and Comparative Example 3 can be observed. The hole observed on the outer side.

The evaluation of the holes on the side of the cylindrical sintered body will be described below.

In the cylindrical sintered body of Example 1 to Example 3 and Comparative Example 1 to Comparative Example 5, the cylindrical sintered body was observed in the cylinder at the central part of the cylinder axis using the above method with an electron microscope (SEM) The organization of the side and outer side, and the equivalent circle diameter of the number of holes and the area of the holes are measured. Each sample is five electron microscope observation samples cut out along the circumferential direction on the inner surface 110-4a of the cylinder of the cylindrical sample 110-4. Observe the field of view of 980 μm×1200 μm from each electron microscope observation sample to calculate the average value of the equivalent circle diameter of the number of holes and the area of the holes. The equivalent circle diameter L of the area S of the hole of the cylindrical sintered body is calculated by the following formula.

。Formula 1:

.

FIG. 18 shows the average value of the equivalent circle diameter 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.

It can be seen from the results in Fig. 18 that compared to the cylindrical sintered bodies of Comparative Examples 2 to 5 in which oxygen is not introduced into the hollow part of the cylindrical shaped body during sintering, oxygen is removed during sintering. The cylindrical sintered bodies of Examples 1 to 3 in which the elements are introduced into the hollow portion inside the cylinder of the cylindrical shaped body have fewer holes on the inner side of the cylinder. In Comparative Example 1 in which the length of the cylinder axis direction is 470 mm or less, even if oxygen is not introduced into the inner hollow portion of the cylinder-forming body, the number of holes on the inner side of the cylinder is small. In the cylindrical inner surface of the cylindrical sintered body of Examples 1 to 3, the average value of the equivalent circle diameter of the hole area is 1 μm or less. On the other hand, in the cylindrical inner surface of the cylindrical sintered body of Comparative Examples 2 to 5, the average value of the equivalent circle diameter of the area of the hole is 4 μm or more. In Comparative Example 1 where the length of the cylinder axis is 470 mm or less, even if oxygen is not introduced into the inner hollow part of the cylinder-forming body, the average equivalent circle diameter of the hole area on the inner side of the cylinder The value can also be 1 μm or less. In addition, as shown in Fig. 18, the number of holes observed on the outer surface of the cylindrical sintered body of Examples 1 to 3 and Comparative Examples 1 to 5 can be 4.25×10 ^-5 /μm ² or less, The average value of the equivalent circle diameter of the hole area can be less than 1 μm.

Although the results of ITO are shown in Examples 1 to 3, this can also be used for cylindrical shaped bodies with a length of 600 mm or more in the direction of the cylindrical axis composed of various components of IZO, IGZO, and AZO. Invented manufacturing method for sintering. However, the manufacturing conditions can be appropriately changed according to each component within the scope of the present invention. As a result, it is possible to prevent the cylindrical sintered body from deforming and cracking during sintering. Moreover, the density of the cylindrical sintered body after sintering can be increased. Furthermore, the relative density difference of the sintered cylindrical sintered body along the cylindrical axis direction can be reduced. It can also reduce the equivalent circle diameter of the hole area observed on the inner surface of the cylinder of the sintered cylindrical sintered body. In addition, the number of holes observed on the inner surface of the cylinder of the sintered cylindrical sintered body can be reduced.

However, the present invention is not limited to the above-mentioned embodiments, and can be appropriately changed without departing from the gist.

100: Cylindrical sputtering target 110, 110a, 110b: Cylindrical sintered body 110-1, 110-2, 110-3: measurement sample 110-4: Cylindrical sample 110-4a: Inside the cylinder 110-4b: The outer side of the cylinder 111: Cylinder Forming Body 120: Space 130: Cylinder substrate 140: brazing material 150: bottom surface 200: Sintering table 230, 230a, 230b: oxygen element supply port 240: pipeline 260: bezel 280: opening 300: Chamber

FIG. 1 is a perspective view of an example of a cylindrical sintered body included in a cylindrical sputtering target of an embodiment of the present invention. 2 shows a cross-sectional view of an example of the structure of an assembled cylindrical sputtering target according to an embodiment of the present invention. FIG. 3 shows a flowchart of a method for manufacturing a cylindrical sintered body according to an embodiment of the present invention. 4 is a perspective view of the process of forming a sintered cylinder into a molded body in a method of manufacturing a cylindrical sintered body according to an embodiment of the present invention. 5 is a cross-sectional view of the process of forming a sintered cylinder into a molded body in a method of manufacturing a cylindrical sintered body according to an embodiment of the present invention. 6 is a plan view of the process of forming a sintered cylinder into a molded body in a method for manufacturing a cylindrical sintered body according to an embodiment of the present invention. FIG. 7 is a plan view of the process of sintering a cylinder to form a molded body in a method for manufacturing a cylindrical sintered body in Modification 1 of an embodiment of the present invention. FIG. 8 is a cross-sectional view of the process of sintering a cylinder to form a molded body in a method for manufacturing a cylindrical sintered body of Modification 2 of an embodiment of the present invention. FIG. 9 is a schematic diagram of the sampling position of the sample taken along the cylinder axis in the cylindrical sintered body of the embodiment and the comparative example of the present invention. FIG. 10 is a table showing the density, the difference in solid density, the relative density, and the maximum relative density difference in the solid of the cylindrical sintered body of the embodiment and the comparative example of the present invention. 11 is a schematic diagram showing the relationship between the length of the cylindrical sintered body and the minimum oxygen element supply amount of the embodiment and the comparative example of the present invention. FIG. 12 is a table showing the difference in the bulk impedance and the impedance value of the solid inner bulk of the cylindrical sintered body of the embodiment and the comparative example of the present invention. FIG. 13 is a schematic diagram of the sampling positions of measuring samples taken along the inner and outer sides of the cylinder in the cylindrical sintered body of the embodiment and the comparative example of the present invention. 14 is an electron microscope (SEM, 1000 times) photograph of the inner surface of the cylinder of the cylindrical sintered body of the embodiment of the present invention and the comparative example. FIG. 15 is an electron microscope (SEM, 1000 times) photograph of the outer surface of the cylindrical sintered body of the embodiment and the comparative example of the present invention. Fig. 16 is an electron microscope (SEM, 5000 times or 2000 times) photographs of the inner surface of the cylindrical sintered body of the embodiment and the comparative example of the present invention. Fig. 17 is an electron microscope (SEM, 5000 times) photograph of the cylindrical outer surface of the cylindrical sintered body of the embodiment of the present invention and the comparative example. Fig. 18 is a table showing the average value of the equivalent circle diameter and the number of holes on the inner side of the cylinder of the cylindrical sintered body of the present invention and the comparative example.

111: Cylinder Forming Body

150: bottom surface

200: Sintering table

230: oxygen supply port

Claims (3)

A cylindrical sintered body, which is a cylindrical sintered body with a length of 470 mm or more in the direction of the cylinder axis. The equivalent circle diameter of the hole area observed on the inner side of a cylinder is 1 μm or less on average. The number of holes observed on the inner side of the cylinder is 4.25×10 ^-5 holes/μm ² or less on average. The cylindrical sintered body according to claim 1, wherein the hole observed on the inner side of the cylinder is at least five independent positions in the center of the cylinder axis, and the visual field is 1.176 mm ^{2 each} . To the hole. A sputtering target, comprising the cylindrical sintered body as described in claim 1 or 2, and a base material arranged in the hollow part inside the cylinder.

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