JP2018154522A - Method for manufacturing cylindrical oxide sintered body and cradle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a cylindrical oxide sintered body having high circularity by suppressing deformation of a cylindrical oxide sintered body.SOLUTION: The method for manufacturing a cylindrical oxide sintered body 2 by sintering a cylindrical oxide molded body using a firing furnace comprises a molding step of filling a raw material powder or granulated powder in a cavity of a cylindrical forming die and pressure-molding to obtain a cylindrical oxide molded body 1, an arranging step of arranging the cylindrical oxide molded body 1 in a firing furnace by using a cradle 10, and a firing step of firing the cylindrical oxide molded body 1 disposed by using a cradle 10 in the firing furnace to obtain a cylindrical oxide sintered body 2. The cradle 10 has a pedestal portion 12, and a recessed portion 14 formed in a concave shape so as to have an outer edge on a top surface side of the pedestal portion and an inclination from the outer edge to a center, and in the arranging step, the cylindrical oxide molded body 1 is placed upright in the recessed portion 14 of the cradle 10.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for producing a cylindrical oxide sintered body for a sputtering target and a base plate used in the production method.

  Conventionally used sputtering targets have a usage efficiency of about several tens to 30% and have a flat plate shape. In recent years, a cylindrical sputtering target having a high efficiency of 70 to 80% for using the sputtering target has attracted attention. Since the cylindrical sputtering target is sputtered while rotating, it is possible to input high power by high-efficiency cooling. Therefore, the cylindrical sputtering target is spreading as a method having a high film formation speed and excellent productivity.

  In addition, since the cylindrical sputtering target is easy to process, it is widely used for metal materials having high mechanical strength. However, a cylindrical sputtering target made of an oxide material has a characteristic that it is generally hard and fragile, and has not yet been sufficiently spread. In particular, since the cylindrical oxide sintered body has a volume shrinkage of 10% to 20% during the sintering process, in Patent Document 1, rolling of a round bar or a spherical ceramic material is performed as a countermeasure for deformation. A deformation suppressing method such as using a sintered jig composed of a used sliding layer and a plurality of ceramic members is disclosed.

JP 2008-184337 A

  However, in Patent Document 1, since the arrangement of the cylindrical oxide sintered body on the sintering jig is complicated and due to free rolling of a round bar or a spherical ceramic material, there is a concern that the effect of suppressing deformation is not stable. The For example, the cylindrical oxide compact moves during thermal contraction during sintering with a slight inclination of the hearth and comes into contact with the furnace wall and the adjacent compact, or oxygen that affects the oxide sintering density, etc. With a floor plate having a gas inlet, the cylindrical oxide compact is moved by the gas pressure due to gas inflow, and the cylindrical oxide sintered body is deformed, making it difficult to ensure its high roundness. It becomes. In addition to the deformation of the cylindrical oxide sintered body, if the reaction with the gas during sputtering is not uniform, there is a problem that the density is not uniform even with a single sintered body. .

  The present invention has been made in view of the above problems, and can suppress the deformation of a cylindrical oxide sintered body and reliably manufacture a cylindrical oxide sintered body with high roundness. It is an object of the present invention to provide a novel and improved method for producing a cylindrical oxide sintered body and a floor plate used in the production method.

  One aspect of the present invention is a method for producing a cylindrical oxide sintered body in which a cylindrical oxide sintered body is produced by sintering a cylindrical oxide molded body using a firing furnace. A molding step of filling a raw material powder or granulated powder into a mold cavity and press-molding to obtain a cylindrical oxide molded body, and placing the cylindrical oxide molded body in the firing furnace via a floor plate And a firing step of obtaining a cylindrical oxide sintered body by firing the cylindrical sintered body formed body disposed through the floor plate in the firing furnace, wherein the floor plate is a pedestal portion. And an outer edge provided on the top surface side of the pedestal portion, and a concave portion formed in a concave shape so as to have an inclination from the outer edge to the center, and in the arranging step, the cylindrical oxide molded body is It arrange | positions by making it stand upright in the said recessed part of a flooring board, It is characterized by the above-mentioned.

  According to one aspect of the present invention, the cylindrical oxide compact is uniformly shrunk toward the center along the inner surface of the recess of the floor plate by its own weight during sintering. A high degree of cylindrical oxide sintered body can be produced efficiently.

  At this time, in one aspect of the present invention, the concave portion of the floor plate may be formed in a concave shape so as to reduce the diameter with the same curvature from the outer edge to the center in all directions.

  In this way, since the tapered portion formed on the bottom surface side of the cylindrical oxide molded body comes into contact with the curved inner surface of the concave portion, the cylindrical oxide molded body is caused by its own weight during sintering. By shrinking uniformly toward the center of the recess of the floor plate, a cylindrical oxide sintered body having high roundness with less distortion and deformation can be efficiently produced.

  In one aspect of the present invention, a cylindrical gas introduction pipe having an outer diameter smaller than the inner diameter of the cylindrical oxide sintered body is erected on the center side of the concave portion of the floor plate. The cylindrical oxide compact may be placed upright so as to cover the gas introduction pipe.

  In this way, since the reaction gas also flows inside the cylindrical oxide compact, the difference in the outer sintering rate is reduced, and the cylindrical oxide compact can be sintered more uniformly. .

  In one embodiment of the present invention, a plurality of gas introduction ports may be provided on a side surface of the gas introduction pipe.

  In this way, the difference in sintering speed between the inside and outside of the cylindrical oxide compact is reduced, so that the cylindrical oxide compact can be sintered more uniformly.

  In one embodiment of the present invention, the floor plate may be formed of alumina or zirconia.

  In this way, the floor plate is formed of a material that has high-temperature durability, the surface state does not easily change, and does not react with the cylindrical oxide molded body during sintering, so a more stable state With this, the cylindrical oxide compact can be sintered.

  In one embodiment of the present invention, the surface roughness of the floor plate may be 3 μm or less in terms of arithmetic average roughness Ra.

  In this way, the cylindrical oxide compact is easily slid along the inner surface of the recess due to its own weight, so that a highly round cylindrical oxide sintered body can be efficiently produced.

  In one embodiment of the present invention, in the molding step, the cylindrical oxide molded body may be obtained by pressure molding by cold isostatic pressing.

  In this way, a cylindrical oxide sintered body having high roundness with less distortion and deformation from a cylindrical oxide molded body in which a taper portion is easily formed on the bottom side by pressure forming by cold isostatic pressing. The body can be manufactured efficiently.

  Another aspect of the present invention is a floor plate interposed when the cylindrical oxide molded body is disposed in a firing furnace, wherein a pedestal portion and an outer edge are provided on the top surface side of the pedestal portion, And a concave portion formed in a concave shape so as to have an inclination from the outer edge to the center.

  According to another aspect of the present invention, the cylindrical oxide compact is uniformly shrunk toward the center along the inner surface of the recess of the floor plate by its own weight during sintering. A high-degree cylindrical oxide sintered body can be efficiently produced.

  As described above, according to the present invention, the cylindrical oxide compact is uniformly shrunk toward the center along the inner surface of the recess of the floor plate by its own weight during sintering. In addition, it is possible to efficiently produce a cylindrical oxide sintered body having high roundness with less distortion and deformation.

It is a flowchart which shows the outline of the manufacturing method of the cylindrical oxide sintered compact concerning one Embodiment of this invention. (A) is a perspective view of a base plate used in the method for producing a cylindrical oxide sintered body according to an embodiment of the present invention, (B) is a plan view of the base plate, (C) These are the sectional views on the AA line of Drawing 2 (B). It is a perspective view which shows the arrangement | positioning state to the baseplate of the cylindrical oxide molded object in the arrangement | positioning process of the manufacturing method of the cylindrical oxide sintered compact concerning one Embodiment of this invention. FIG. 4 is a sectional view taken along line BB in FIG. 3. It is an enlarged view of the C section of FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail. The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are essential as means for solving the present invention. Not necessarily.

  First, the outline of the manufacturing method of the cylindrical oxide sintered compact concerning one embodiment of the present invention is explained using a drawing. FIG. 1 is a flowchart showing an outline of a method for producing a cylindrical oxide sintered body according to an embodiment of the present invention.

  The manufacturing method of the cylindrical oxide sintered compact which concerns on one Embodiment of this invention manufactures the cylindrical oxide sintered compact used as the cylindrical oxide target material used as a sputtering target in a magnetron type | mold rotary cathode sputtering device. It is applied when doing. Specifically, it is applied when a cylindrical oxide sintered body is produced by sintering a cylindrical oxide compact for a sputtering target using a firing furnace.

  The method for manufacturing a cylindrical oxide sintered body according to the present embodiment includes a forming step S11, an arrangement step S12, and a firing step S13, and these steps S11 to S13 are performed according to the flow shown in FIG. As a result, a cylindrical oxide sintered body is produced.

The forming step S11 is a step of filling a raw material powder or granulated powder into a cavity of a cylindrical forming mold and press-molding it by a CIP method or the like to obtain a cylindrical oxide molded body. In the present embodiment, the raw material powder is not particularly limited, and can be appropriately selected according to the composition of the target cylindrical sputtering target. For example, when obtaining a cylindrical sputtering target made of ITO (Indium Tin Oxide), indium oxide (In ₂ O ₃ ) powder and tin oxide (SnO) powder can be used as the raw material powder. Further, in order to obtain a cylindrical sputtering target made of AZO (Aluminium Zinc Oxide) as the raw material powder, aluminum oxide _(Al 2 _{O 3)} can be used powder and zinc oxide (ZnO) powder.

  In addition, after mixing the raw material powder at a predetermined ratio, it can be molded as it is, but after mixing with pure water, a binder, a dispersing agent, etc., spray-dried, and then granulated powder It is preferable to fill the cavity. The granulated powder has higher fluidity than the raw material powder and is excellent in filling property. For this reason, by using the granulated powder instead of the raw material powder, a high-density cylindrical oxide compact can be easily obtained even in industrial scale production.

  In the present embodiment, the molding is performed by pressure molding by CIP (Cold Isostatic Pressing) molding. The pressure molding is generally CIP molding, but is not limited to CIP molding as long as a high-density cylindrical formed body can be obtained. In the case of CIP molding, a raw material powder or granulated powder is filled in a cavity, and then a cylindrical forming mold is put into a CIP apparatus and pressure-molded.

  In order to prevent a pressure medium such as water from entering the mold, the cylinder-forming mold may be vacuum-packed and put into the CIP device. The holding pressure in CIP molding is preferably 98 MPa to 294 MPa. If the holding pressure is less than 98 MPa, the density of the obtained cylindrical oxide compact may not be sufficiently high. On the other hand, when the holding pressure exceeds 294 MPa, the load on the CIP device is excessively increased and the production cost is increased.

  At this time, the time for holding at the holding pressure (holding time) is preferably 1 minute to 30 minutes, and more preferably 3 minutes to 10 minutes. If the holding time is less than 1 minute, the density of the obtained cylindrical oxide compact may not be sufficiently high. On the other hand, if the holding time exceeds 30 minutes, productivity will deteriorate.

  In arrangement | positioning process S12, it is a process of arrange | positioning a cylindrical oxide molded object through a base plate in a baking furnace. In the present embodiment, in order to efficiently produce a highly round cylindrical oxide sintered body with less sintering deformation, the base plate on which the cylindrical oxide molded body is disposed is inclined in a mortar shape. It is characterized by that.

  As a result of intensive studies in order to achieve the above-described object of the present invention, the present inventor makes the bottom plate used in the placement step S12 into a mortar shape, so that the cylindrical oxide molded body is self-weighted during sintering. The present inventors have found that a cylindrical oxide sintered body having high roundness with less distortion and deformation can be efficiently produced because it is uniformly shrunk toward the center along the mortar-shaped inclination. As a result of further research based on these findings, the present invention has been completed.

  Specifically, the bottom plate is provided with a concave portion formed in a concave shape so as to reduce the diameter with the same curvature from the outer edge to the center on the top surface side of the substantially cylindrical pedestal portion. It has a shape. And in arrangement | positioning process S12, it arrange | positions by making a cylindrical oxide molded object stand upright in the recessed part of a baseplate, It is characterized by the above-mentioned. In addition, the detailed structure of the flooring board in this embodiment and detailed description of arrangement | positioning process S12 using the said flooring board are mentioned later.

  The firing step S13 is a step of obtaining a cylindrical oxide sintered body by firing the cylindrical oxide molded body that is disposed in the firing furnace in the placing step S12 via a floor plate. The firing conditions of the cylindrical oxide molded body should be appropriately selected according to the composition, size, characteristics of the firing furnace, etc., and are not particularly limited, but can be fired under the following conditions. it can.

  In the firing step S13, the organic component contained in the cylindrical oxide molded body is removed by first raising the temperature from room temperature to a specific temperature (binder removal temperature) over a certain period of time (binder removal time). It will be necessary. The binder removal temperature at this time is preferably 300 ° C. to 600 ° C., more preferably 400 ° C. to 500 ° C. The binder removal time is preferably 50 hours to 300 hours, more preferably 100 hours to 300 hours. With such a binder removal temperature and binder removal time, the organic components contained in the cylindrical oxide compact can be sufficiently removed.

During the binder removal stage, it is necessary to supply atmospheric gas at a rate of 100 L / min to 600 L / min, preferably 200 L / min to 400 L / min per 1 m ³ of the furnace volume. The atmosphere may be air, oxygen, or any mixed gas thereof.

  After the binder removal step, the temperature in the furnace is raised to the firing temperature, and the cylindrical oxide compact is sintered by holding at this temperature for a certain period of time. The firing temperature varies depending on the composition of the cylindrical oxide molded body. For example, when indium oxide is the main component, the firing temperature is preferably 1200 ° C. to 1600 ° C., and the cylindrical oxide sintered body has a high density. It is more preferable to set it as 1300 degreeC-1600 degreeC from a viewpoint which obtains.

  On the other hand, when zinc oxide is the main component, the temperature is preferably 1000 ° C to 1400 ° C, and more preferably 1250 ° C to 1350 ° C from the same viewpoint. The holding time at the firing temperature is preferably 5 hours to 40 hours, more preferably 10 hours to 30 hours.

Incidentally, the atmosphere in the sintering step varies depending on the composition of a cylindrical molded oxide product, air or oxygen, depending on the composition or mixed gas thereof, 100L / min ～600L / min per furnace capacity 1 m ^3,, Preferably, 200 L / min to 400 L / min are supplied.

  Next, the detail of the structure of the baseplate used with the manufacturing method of the cylindrical oxide sintered compact which concerns on one Embodiment of this invention is demonstrated, using drawing. FIG. 2 (A) is a perspective view of a base plate used in the method for producing a cylindrical oxide sintered body according to one embodiment of the present invention, and FIG. 2 (B) is a plan view of the base plate. FIG. 2C is a cross-sectional view taken along the line AA in FIG.

  The floor plate 10 used in the method for manufacturing a cylindrical oxide sintered body according to the present embodiment is integrally molded from alumina or zirconia, which is a material having high temperature durability and heat resistance and having a stable surface state. As shown in FIG. 2A, the pedestal portion 12, the concave portion 14, and the gas introduction pipe 16 are provided. In the present embodiment, the floor plate 10 is integrally molded. However, the floor plate 10 may be formed by assembling a plurality of parts such as a pedestal part and a gas introduction pipe separately.

  The pedestal portion 12 is a substantially cylindrical substrate that supports a cylindrical oxide molded body to be fired in a firing furnace. As shown in FIGS. 2A to 2C, the recess 14 has an outer edge 14 a provided on the top surface side of the pedestal portion 12, and an inner side surface 14 b that is the same in all directions from the outer edge 14 a to the center O. It is formed in a concave shape so as to be reduced in diameter by the curvature, and the bottom surface side of the inner side surface 14b is a mounting surface for the cylindrical oxide molded body. The gas introduction pipe 16 is a cylinder erected on the center side of the recess 14 in order to introduce gas into the inner peripheral surface of the cylindrical oxide molded body placed on the inner surface 14 b of the recess 14 of the floor plate 10. It is a shaped member.

  In this embodiment, when a cylindrical oxide sintered body is produced by sintering a cylindrical oxide molded body in a firing furnace, a highly round cylindrical oxide sintered body with less sintering deformation is produced. In order to obtain a bonded body, the floor plate 10 used when placing the cylindrical oxide compact in the firing furnace in the placement step is provided with an outer edge 14a on the top surface side of the base portion 12 on the base portion 12, A recess 14 that is inclined from the outer edge 14a to the center O, that is, in a mortar-like shape, is provided.

  Specifically, the mortar-shaped inclination from the position where at least the cylindrical oxide molded body is erected to the center O of the floor plate 10 is in the range of 20 to 30 degrees when the bottom surface side of the recess 14 is regarded as a tapered surface. It is preferable to do. Further, when the shape of the bottom surface side of the concave portion 14 is defined by the radius of curvature, the curvature radius of the cross section of the concave portion 14, that is, the curvature radius of the curved surface on the bottom surface side of the inner side surface 14b of the concave portion 14 is When the outer diameter is 200 mm, it is 160 mm or more and 200 mm or less.

  Thus, in this embodiment, since the floor board 10 used at an arrangement | positioning process becomes a structure which has a mortar-like inclination, when the cylindrical oxide molded object is mounted in the bottom face side of the recessed part 14 of the floor board 10 In addition, when the molded body is sintered, it shrinks uniformly in all directions toward the center along the inner side surface 14b of the recess 14 of the floor plate 10 by its own weight. For this reason, it becomes possible to efficiently produce a cylindrical oxide sintered body having a high roundness with less distortion and deformation.

  In the present embodiment, the floor plate 10 is made of a stable material that has high-temperature durability, whose surface state does not easily change, and does not chemically react with the cylindrical oxide molded body during firing. It is preferably made of alumina or zirconia. The surface of the floor plate 10 is not particularly limited, but since the sintered body obtained by sintering the cylindrical oxide molded body preferably has a surface roughness that is sufficiently slippery due to its own weight, the surface roughness Ra is 3 μm or less.

  Furthermore, in this embodiment, a cylindrical gas introduction pipe 16 for introducing a gas such as oxygen into the inside of the cylindrical oxide compact to be sintered is erected on the center side of the recess 14 of the floor plate 10. ing. As shown in FIGS. 2A to 2C, the gas introduction pipe 16 is a tubular member whose both ends are a bottom side gas introduction port 16 b and a top side gas introduction port 16 c, and a plurality of side surface side gases are provided on its side surface. Introducing ports 16a are provided at predetermined intervals.

  The outer diameter of the gas introduction tube 16 is preferably sufficiently smaller than the inner diameter of the sintered and contracted cylindrical oxide sintered body, and is set at least 20% to 40% smaller than the inner diameter of the sintered body after sintering. The height of the gas introduction pipe 16 is at least the height of the sintered body after sintering in order to stably support the molded body after introducing gas more uniformly into the inner peripheral surface side of the molded body. Set to 1/3 or higher. For example, when the sintered cylindrical oxide compact has an inner diameter of about 130 mm and a height of 260 mm, the gas inlet tube 16 has an outer diameter of 90 mm and a height of 130 mm.

  Further, in the present embodiment, by providing the side gas inlet 16a on the side surface of the gas introduction pipe 16, gas can be sprayed on the molded body, so that the molded body is compared with the case where there is no side gas inlet 16a. Since the inside sintering speed is increased and there is no difference between the inside and outside of the molded body, sintering can be performed more uniformly. One or a plurality of side-side gas introduction ports 16a can be provided, but a plurality of side-side gas introduction ports 16a are preferably provided uniformly in order to sinter the molded body more uniformly. The size of the side gas inlet 16a is not particularly limited, but is preferably 20 mm to 30 mm in diameter.

  Thus, by providing the gas introduction pipe 16 having a plurality of gas introduction ports 16a on the side surface side so that the reaction gas flows into the inside of the cylindrical oxide molded body, The difference between the reaction gas and the sintering rate on the outer side of the compact is reduced after the reaction gas is applied more uniformly on the inner side. For this reason, it becomes possible to sinter a uniform cylindrical oxide molded body with further reduced density variation.

  In addition, the supply rate and supply density of the reaction gas such as oxygen introduced into the compact disposed in the firing furnace affect the sintered density of the oxide. Furthermore, since the position of the cylindrical oxide molded body may move even with gas pressure due to gas flow into the firing furnace, the density of the sintered body to be produced becomes stable due to non-uniform reaction with the gas. There is concern about not doing it.

For this reason, the shape and size of the bottom side gas inlet 16b are not particularly limited, but if it is too small, the gas flow rate is insufficient and sintering of the molded article becomes insufficient, and if it is too large, the cylindrical oxide Since the sintered body cannot be supported, the bottom side gas inlet 16b is preferably disposed at the approximate center of the floor plate, and the opening area is preferably about 50 cm ² or less per molded body.

  Next, the operation and effect of using a floor plate in the arranging step of the method for producing a cylindrical oxide sintered body according to an embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a perspective view showing an arrangement state of a cylindrical oxide molded body on a floor plate in an arrangement step of the method for producing a cylindrical oxide sintered body according to an embodiment of the present invention. 3 is a cross-sectional view taken along line BB in FIG. 3, and FIG. 5 is an enlarged view of a portion C in FIG.

  When producing a cylindrical oxide molded body, after filling raw material powder or granulated powder into the cavity of the cylindrical forming mold, the cylindrical forming mold is put into a CIP apparatus, and press-molded. Since the pressure is evenly applied, as shown in FIG. 4, the molded body 1 press-molded by CIP has a top surface side end portion 1 a and a bottom surface side end portion 1 b that are formed from the inner diameter toward the outer diameter. Taper with a curved surface. That is, as shown in FIGS. 3 and 4, the top surface side end portion 1a of the cylindrical oxide molded body 1 has a tapered shape that falls from the inside toward the outside, and the bottom surface side end portion 1b has the shape shown in FIGS. As shown in FIG. 5, the taper is raised from the inside toward the outside.

  Further, when the cylindrical oxide molded body 1 is sintered at a predetermined temperature, the cylindrical oxide molded body 1 contracts by about 10 to 20%, but the top surface side end portion 1a and the bottom surface side end portion 1b of the cylindrical oxide molded body 1 are shrunk. The size of the taper from the inner diameter to the outer diameter is substantially the same before and after sintering the molded body 1 as shown in FIGS. For this reason, in this embodiment, it is set as the structure which matches the magnitude | size of the taper of the bottom face side edge part 1b of the cylindrical oxide molded object 1 with the mortar-shaped inclination of the recessed part 14 of the flooring board 10. FIG.

  Specifically, for example, if the outer diameter of the cylindrical oxide molded body 1 is about φ200 mm, a mortar extending from the position where the cylindrical oxide molded body 1 of the concave portion 14 of the floor board 10 stands upright to the center O of the floor board 10. In the case of a taper, the shape inclination is preferably 20 to 30 degrees and the radius of curvature is preferably 160 to 200 mm, and particularly preferably 180 mm. Further, the mortar-shaped inclination of the recess 14 of the floor plate 10 is more preferable because the R shape is closer to the tapered shape of the top surface side end portion 1a and the bottom surface side end portion 1b of the cylindrical oxide molded body 1. Thus, by matching the concave portion 14 of the floor plate 10 with the shape of the bottom side end 1b of the cylindrical oxide molded body 1, the molded body 1 can be supported uniformly, and the molded body during sintering can be supported. It is also effective in preventing falls.

  In addition, when there is little mortar-shaped inclination of the recessed part 14 of the flooring board 10, slip will become inadequate, it will become difficult for the cylindrical oxide molded object 1 to shrink | contract concentrically, and high roundness cannot be maintained. For this reason, it is preferable that the inclination angle of the concave portion 14 of the floor plate 10 is an inclination angle at which the molded body 1 is sufficiently slippery. Therefore, as described above, the inclination of the concave portion 14 has a curvature that falls within the numerical range described above. An R-shaped inclination with a radius is preferable. In the case of a linear taper, an inclination of 20 to 30 degrees is preferable.

  Thus, in the present embodiment, by supporting the cylindrical oxide molded body 1 using the mortar-shaped floor plate 10, the cylindrical oxide molded body 1 is formed on the floor plate 10 by its own weight during sintering. The concave portion 14 is uniformly shrunk toward the center along the mortar-shaped inclination. For this reason, the cylindrical oxide sintered body 2 having a high roundness with little distortion and deformation even after the sintering step can be obtained efficiently.

  In particular, in the present embodiment, using a mortar-shaped floor plate in which a recess is formed in accordance with the shape of the taper formed on the bottom surface side of a cylindrical oxide molded body obtained by pressure molding with CIP, Since the compact is supported and fired, when the cylindrical oxide compact obtained by pressure molding with CIP is fired to produce a cylindrical oxide sintered body, distortion and A cylindrical oxide sintered body having a high degree of roundness with little deformation can be obtained.

  Thus, as a countermeasure against shrinkage deformation accompanying high-temperature sintering of the cylindrical oxide molded body, it is not a complicated configuration due to rolling of a round bar or a sphere as in the past, but in this embodiment, alumina, zirconium, etc. A cylindrical oxide sintered body having a high roundness can be easily obtained by supporting the molded body using a mortar-shaped flooring board as a flooring board to be a furnace-fired plate made of a heat-resistant ceramic. It has become.

  That is, in this embodiment, the cylindrical oxide compact itself is sintered without affecting the natural action of uniform thermal contraction of the cylindrical oxide compact by applying a force attracted by gravity to the dimensional change due to the thermal contraction. As a result, a cylindrical oxide sintered body in which roundness is hardly lowered during the firing step can be obtained from a cylindrical oxide molded body having a roundness of 1.0 before sintering.

  In conventional cylindrical oxide sintered bodies with low roundness, the inner and outer diameters of the sintered body tend to be distorted and the cross section tends to be elliptical. In order to obtain a cylindrical oxide processed body with a high roundness that is suitable for brazing with a material, a large-sized large-sized part that takes into account the distortion and ellipticity of the inner and outer diameters of the sintered body has been increased. A molded body was needed. For this reason, the cost increases due to excessive use of the raw material powder, and the processing time for grinding the excessive amount of the sintered body is increased, and the productivity such as shortening the wear deterioration of the processing wheel is increased. It was a problem in.

  In contrast, in the method for manufacturing a cylindrical oxide sintered body according to the present embodiment, it is possible to stabilize the roundness of the cylindrical oxide sintered body at a high level. The volume of the cylindrical oxide compact can be determined without considering the above. For this reason, while saving the raw material powder, by reducing the grinding time of the processed body requiring high roundness and suppressing the consumption deterioration of the processing wheel, as a result of the cylindrical oxide processed body Since productivity can be improved, it has an extremely large industrial value.

  Next, a method for producing a cylindrical oxide sintered body according to an embodiment of the present invention will be described in detail with reference to examples. The present invention is not limited to these examples.

Example 1
Example 1 was a Sn—Zn—O-based oxide sintered body. In this example, first, zinc oxide powder and tin oxide powder were weighed at a ratio of tin oxide powder of 47.6% by mass, and pure water and binder were mixed so that the concentration of the raw material oxide powder was 65% by mass. Polyvinyl alcohol (PVA) and a dispersant were added and mixed and pulverized with a bead mill (manufactured by Ashizawa Finetech Co., Ltd.) to obtain a desired slurry. This slurry is spray-dried with a spray dryer (Okawara Kako Co., Ltd.) to obtain a spherical granulated powder having a specific gravity of about 2 g / cm ³ . It is put into a cold isostatic press (cold isostatic pressing, CIP) device to produce a cylindrical oxide molded body having an outer diameter of 200 mm, an inner diameter of 160 mm, and a height of 300 mm, and an atmospheric pressure firing furnace (Marusho) High temperature firing at Denki Co., Ltd.) to obtain four cylindrical oxide sintered bodies.

  In this example, at the time of sintering, the cylindrical oxide molded body and the alumina base plate having a diameter of 300 mm were arranged so that the central axis of the cylindrical oxide molded body and the central axis of the base plate substantially coincide (see FIG. 3). . Specifically, the mortar for the floorboard was a concave surface processed with a radius of curvature of 180 mm and a surface roughness Ra of 3 μm or less. In addition, a hollow gas introduction pipe for introducing a gas affecting the sintering density was installed at the bottom of the mortar of the floor plate. The gas introduction tube had an outer diameter of 90 mm, an inner diameter of 40 mm, and a height of 130 mm. Furthermore, four inlets with a diameter of 30 mm were provided in the lateral wall of the gas inlet tube. The reason why the arithmetic average roughness Ra on the surface of the floor plate is 3 μm or less is that the ease of slipping of the cylindrical oxide molded body is taken into consideration.

  Further, the sintering step is performed by removing the binder by raising the temperature to 450 ° C. while flowing air through the gas introduction pipe of the flooring plate according to an embodiment of the present invention disposed in the atmospheric pressure firing furnace, and then oxygen gas. The temperature was raised to 1350 ° C. while flowing, and sintering was performed to produce a cylindrical oxide sintered body. All of the four cylindrical oxide sintered bodies taken out after cooling of these cylindrical oxide sintered bodies have a diameter of about 165 mm, an inner diameter of about 130 mm, and a height of about 4 mm, without greatly deviating from the center axis positions originally arranged. Shrink to 260 mm. Furthermore, as a result of measuring the inner diameter of the sintered body at the lower end of the sintered body using calipers, the difference between the maximum value and the minimum value is 0.8 mm on average and the roundness is about 0.99. A ligation was obtained.

  Thereafter, the cylindrical oxide sintered body is ground to an outer diameter of 155 mm, an inner diameter of 135 mm, and a height of 240 mm, and brazed with an In brazing material to a cylindrical backing tube having an outer diameter of 133 mm, an inner diameter of 125 mm, and a length of 300 mm. When a cylindrical sputtering target having a length of 300 mm was prepared and subjected to DC sputtering, there was no abnormal discharge during sputtering and no cracking of the target. Sputtering was performed by introducing Ar gas having a power of 2.5 kW and 0.3 Pa.

(Comparative Example 1)
Four cylindrical oxide sintered bodies were produced in the same manner as in Example 1 except that the mortar-shaped floor plate according to one embodiment of the present invention was not used. As a result, the sintered body of Comparative Example 1 also did not move greatly in the furnace position, but all four were deformed in an elliptical shape. When the inner diameter of the lower end of the sintered body was measured using calipers, the difference between the maximum value and the minimum value was 6.0 mm on average and about 0.96 in roundness. In addition, when the four cylindrical sintered bodies were ground to an outer diameter of 155 mm, an inner diameter of 135 mm, and a height of 240 mm, two cracks were generated, and one without any remaining cracks had an outer diameter of 133 mm and an inner diameter of A cylindrical target having a length of 300 mm was produced by brazing a backing tube having a length of 125 mm and a length of 300 mm using an In brazing material.

  However, when Ar gas having a power of 2.5 kW and 0.3 Pa was introduced and DC sputtering was performed, abnormal discharge occurred and cracks occurred in the target. For this reason, the broken workpiece is removed from the backing tube, and the unbroken workpiece is brazed with an In brazing material to produce a cylindrical target. When DC sputtering is performed again under the above conditions, the discharge is normally performed. The target was not cracked.

  The difference in inner diameter of each of the four cylindrical oxide sintered bodies shown in Example 1 and Comparative Example 1, the roundness calculated from the inner diameter difference, and cracks after grinding each sintered body About the presence or absence, the effect by the manufacturing method of the cylindrical oxide sintered compact concerning one Embodiment of this invention was put together in the following Table 1, and was arranged.

  As shown in Table 1, the roundness of the sintered body in Example 1 was a high roundness of 0.99 or more for all four pieces, and the number of cracks in the processed body was zero out of four. The roundness of the sintered body in Example 1 was uneven and the roundness of the sintered body was 0.93. In addition, cracks occurred in the two sintered bodies having a relatively low roundness among the four when formed into a processed body. This is because when the sintered body of Comparative Example 1 progresses in sintering, the round shape of the cross section of the molded body, which was originally 1.0, is deformed into an elliptical shape, thereby causing distortion in the sintered body. As a result, it is considered that the distortion was influenced by the external force during grinding and caused cracking of the workpiece.

  The reason why the cross section of the molded body was deformed into an elliptical shape in this way was to prevent the natural uniform thermal contraction of the molded body due to accidental catching at the contact portion between the bottom of the cylindrical oxide molded body and the bottom plate. It is thought to be due to. In addition, it was confirmed that the roundness of the molded body before sintering was 1.0 in both Example 1 and Comparative Example 1.

  From the above results, when producing a sintered body by sintering the formed body in a firing furnace, compared to Comparative Example 1 in which the mortar-shaped floor plate according to one embodiment of the present invention was not used, a mortar shape In Example 1 using the base plate, it was found that since the sintered body having higher roundness was produced without variation, the occurrence of cracks in the sintered body was suppressed. From this, a sintered body having a higher roundness is reliably produced by applying the floor plate in the method for producing a cylindrical oxide sintered body according to an embodiment of the present invention. It was found that cracking of the steel can be suppressed.

  Although the embodiments and examples of the present invention have been described in detail as described above, it will be understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. It will be easy to understand. Therefore, all such modifications are included in the scope of the present invention.

  For example, a term described with a different term having a broader meaning or the same meaning at least once in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings. Further, the structure of the base plate used in the method for manufacturing the cylindrical oxide sintered body and the operation of the method for manufacturing the cylindrical oxide sintered body are not limited to those described in the embodiments and examples of the present invention. Various modifications are possible.

DESCRIPTION OF SYMBOLS 1 Cylindrical oxide molded object, 1a Top part side inclined surface, 1b Bottom side side inclined surface, 2 Cylindrical oxide sintered body, 10 Base plate, 12 base, 14 recessed part, 14a Outer edge part, 14b Inner side surface, 16 Gas introduction pipe | tube 16a (side surface side) gas inlet port, 16b (bottom side) gas inlet port, 16c (top side) gas inlet port, S11 molding step, S12 placement step, S13 firing step

Claims (8)

A method for producing a cylindrical oxide sintered body for producing a cylindrical oxide sintered body by sintering a cylindrical oxide molded body using a firing furnace,
A molding step of filling a raw material powder or granulated powder into a cavity of a cylindrical mold and obtaining a cylindrical oxide molded body by pressure molding;
An arrangement step of arranging the cylindrical oxide compact in the firing furnace via a floor plate;
Firing a cylindrical sintered compact formed through the floor plate in the firing furnace to obtain a cylindrical oxide sintered body, and
The floor plate includes a pedestal portion, and a concave portion formed in a concave shape so that an outer edge is provided on a top surface side of the pedestal portion and has an inclination from the outer edge toward the center,
In the arranging step, the cylindrical oxide compact is disposed in an upright manner in the concave portion of the floor plate.   2. The method for producing a cylindrical oxide sintered body according to claim 1, wherein the concave portion of the floor plate is formed in a concave shape so as to reduce the diameter with the same curvature in all directions from the outer edge to the center. . A cylindrical gas inlet pipe having an outer diameter smaller than the inner diameter of the cylindrical oxide sintered body is erected on the center side of the recess of the floor plate,
The cylindrical oxide sintered body according to claim 1 or 2, wherein in the arranging step, the cylindrical oxide sintered body is arranged upright so as to cover the gas introduction pipe. Method.   The method for producing a cylindrical oxide sintered body according to claim 3, wherein a plurality of gas inlets are provided on a side surface of the gas inlet pipe.   The method for producing a cylindrical oxide sintered body according to any one of claims 1 to 4, wherein the floor plate is made of alumina or zirconia.   The method for producing a cylindrical oxide sintered body according to any one of claims 1 to 5, wherein the surface roughness of the floor plate is 3 μm or less in terms of arithmetic average roughness Ra.   The cylindrical oxide firing according to any one of claims 1 to 6, wherein in the molding step, the cylindrical oxide compact is obtained by pressure molding by cold isostatic pressing. A method for producing a knot. A base plate interposed when the cylindrical oxide molded body is disposed in the firing furnace,
A pedestal,
An outer edge is provided on the top surface side of the pedestal portion, and a floor plate having a recess formed in a concave shape so as to have an inclination from the outer edge to the center.