CN107614739B

CN107614739B - Cylindrical sputtering target material roasting device and roasting method

Info

Publication number: CN107614739B
Application number: CN201680002852.1A
Authority: CN
Inventors: 久保田善明; 森冈稔裕
Original assignee: Hiroki Corp
Current assignee: Hiroki Corp
Priority date: 2016-05-12
Filing date: 2016-05-12
Publication date: 2020-08-14
Anticipated expiration: 2036-05-12
Also published as: JPWO2017195311A1; KR20170138986A; CN107614739A; KR101892877B1; WO2017195311A1; JP6198363B1; TW201740068A; TWI636227B

Abstract

The invention provides a baking device for manufacturing a long cylindrical sputtering target used in the case of manufacturing a transparent conductive film used in a liquid crystal display element, a solar cell, or the like by a sputtering method. The roasting device is characterized in that the following components are arranged: the apparatus for manufacturing the baking furnace includes a fixed hearth for vertically placing a long cylindrical target to be baked on, a baking furnace main body including a plurality of heaters and oxygen inlets provided in a furnace inner wall surface, the fixed hearth being disposed at the center, and a mechanism for placing the baking furnace main body on a traveling carriage so that the baking furnace main body travels along a rail between a baking position and a waiting position and for sealing and opening the furnace between a lower portion of the baking furnace and the fixed hearth.

Description

Cylindrical sputtering target material roasting device and roasting method

Technical Field

The present invention relates to a baking apparatus for a cylindrical sputtering target, and more particularly to an apparatus for baking an oxide-baked body for manufacturing a long cylindrical sputtering target used in the case of manufacturing a transparent conductive film used for a liquid crystal display element, a solar cell, or the like by a sputtering method.

Background

Transparent conductive films have high conductivity and high transmittance in the visible light region, and thus are used for various light-receiving element electrodes and the like of liquid crystal display elements, solar cells, and the like. Since a film having high transmittance and low resistance can be obtained as the transparent conductive film, a tin oxide-indium oxide film (ITO film), an aluminum oxide-zinc oxide film (AZO film), and an indium oxide-gallium oxide-zinc oxide film (IGZO film) are widely used.

As a method for producing a transparent conductive film formed of such an oxide film, a sputtering method is used. In the sputtering method, generally, 100% argon gas of about 10Pa or less is introduced, a sputtering target which is a film material is set as a cathode, argon plasma is generated in a state where a substrate is set in parallel with the target, and when argon cations collide with the target, particles of the target component which fly off are deposited on the substrate to form a film. Conventionally, magnetron sputtering in which sputtering is performed while applying a magnetic field to a cathode has been used in order to increase a film formation rate.

When a flat sputtering target is used as the sputtering target, since erosion occurs by concentrating plasma at a specific portion of a flat sputtering target material by a magnetic field in the magnetron sputtering method, the service life is extended when the deepest portion of the erosion reaches the backing plate, and as a result, there is a problem that the use efficiency of the target stays at 20 to 30%.

In order to cope with this problem, a cylindrical sputtering target is used, and sputtering is performed while rotating the cylindrical sputtering target by providing a magnetic field generating means and a cooling means inside a cylindrical backing tube (backing tube), so that the target use efficiency can be improved to 60 to 70%. One of the methods for producing the cylindrical sputtering target is a sintering method.

The sintering method is a method of adding water, a binder and a dispersant to a raw material oxide powder, mixing them to form a slurry, granulating the slurry with a spray dryer or the like, molding a cylindrical sputtering target with a cold isostatic press (CIP method) or the like, and firing and molding the obtained molded body at normal pressure in a high-temperature atmosphere in which an oxygen-containing gas flows, thereby producing a high-density target having a relative density of 90% or more.

However, when a cylindrical sputtering target is formed by the sintering method, there is a problem that cracks and/or cracks, deformation, warpage, and fine cracks are generated in the sintered body when the oxide sintered body is fired. In the sputtering method, in order to stably obtain a film having uniform characteristics with a uniform film thickness, it is desirable to make the density, the grain size, and the volume resistance of the oxide sintered body uniform.

In view of this problem, there has been disclosed a conventional technique for obtaining a high-quality oxide sintered body for a cylindrical sputtering target, which has a high density and a high bulk uniformity and is suppressed in defects such as cracks, and deformations not only during firing but also during the manufacturing process of the cylindrical sputtering target after firing and/or during sputtering.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication Nos. 2012 and 126587 ([0019 to 0021], [0024 to 0026], [ FIG. 1])

Disclosure of Invention

Problems to be solved by the invention

With respect to the above-mentioned prior art, in the case of using a rectangular electric furnace in which a cylindrical sputtering target compact having a size of 15cm diameter × 20cm length to 20cm diameter × 30cm length is a target to be fired, and allowing an atmosphere gas such as oxygen to flow from below toward above in the furnace, the problems that the flow path of the oxygen-containing gas becomes uneven in the height direction in the furnace and/or on the inside and outside of the compact, and the temperature distribution in the furnace becomes uneven are solved; by appropriately setting the positions and the number of pipes for supplying the atmosphere gas, uniform flow paths for the atmosphere gas are formed between the outer side and the inner side in the height direction of the cylindrical molded body, and the temperature distribution in the furnace is made uniform to perform uniform sintering.

On the other hand, the length of the cylindrical sputtering target obtained by the prior art is 20 to 30cm, 5 to 10 cylindrical sputtering targets need to be stacked in order to manufacture a long cylindrical sputtering target of 1.5 to 3m by using the cylindrical sputtering target, and the targets are joined by welding, but if the height difference of the joint dividing part is not set to be less than 0.5mm, the generation of arc discharge and/or particles cannot be inhibited. Therefore, when the number of divisions is increased, the number of times of generation of arc discharge is increased, and breakage of the division portions is likely to occur, and there is a problem that labor and time for welding are consumed, and production efficiency is deteriorated in manufacturing.

In order to solve this problem, it is required to manufacture and use a cylindrical sputtering target having a size as long as possible, and as one of them, it is required to bake a cylindrical sputtering target material having a long size so as to achieve excellent quality. In the conventional baking of a flat plate-shaped sputtering target and/or a short cylindrical sputtering target, a baking furnace having a low furnace height is used. These baking furnaces are configured to carry a flat and/or short cylindrical sputtering target as an object to be baked into a furnace and transfer the target into the furnace for baking. When this furnace is applied to firing of a long cylindrical sputtering target, if collapse, inclination, or the like cannot be completely prevented when a long object to be fired is carried into the furnace, uniform firing cannot be achieved, and in the worst case, collapse may occur and damage may occur.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a baking apparatus and a baking method which can perform baking with reduced variation in quality in the height and/or diameter direction of a target object without damaging the long target object when a plurality of long cylindrical sputtering targets are erected for baking.

Means for solving the problems

In order to achieve the above object, the firing device for a cylindrical sputtering target according to claim 1 of the present invention has a length of 1.5 to 2m, and includes: a fixed hearth for placing the long cylindrical sputtering target material on the target object in an upright state; a roasting furnace main body which is arranged so as to enclose the fixed hearth and in which a plurality of heaters are provided on an inner wall surface of the furnace; and a roasting furnace traveling device for placing the roasting furnace body on a traveling carriage so that the roasting furnace body can be separated from a position in which the fixed hearth is enclosed and can travel along a rail to a waiting position, wherein a furnace shell door that can be opened and closed so as not to interfere with the process of enclosing the fixed hearth is provided on one side of the roasting furnace body, a sealing portion that prevents air leakage is provided between the lower portion of the furnace shell of the roasting furnace and the peripheral portion of the fixed hearth, and a furnace sealing elevating device that presses and seals the sealing portion by moving the roasting furnace body downward during roasting is provided.

The cylindrical sputtering target material is a long cylindrical sputtering target material with the diameter of 150-300 mm, the thickness of the layer of 10mm and the length of 1.5-2 m. The calcination is carried out at a high temperature of 1250-1700 ℃ in an oxygen atmosphere for 3-30 hours. By adopting the invention according to claim 1, when a plurality of long cylindrical sputtering targets are actually fired, since the firing furnace main body and the traveling device are separated from each other at the waiting position, the operation of placing the cylindrical sputtering targets at appropriate positions on the fixed hearth can be surely performed. Further, the baking furnace main body is moved to the baking position and returned to surround the fixed hearth, but since the furnace door of the baking furnace is fully opened and moved, the cylindrical sputtering target can be placed in the baking furnace and baked without damaging the cylindrical sputtering target. Further, since the furnace sealing elevating device for preventing the gap between the roasting furnace main body and the fixed hearth is provided at the roasting position, the sealing between the inside and the outside of the furnace can be completely performed, and thus the high roasting temperature can be appropriately maintained at each position in the furnace. Thus, a long cylindrical sputtering target of uniform and appropriate quality can be obtained by firing.

The baking apparatus for a cylindrical sputtering target according to claim 2 is characterized in that the furnace sealing elevating means is configured as follows: the lower part of the roasting furnace body is provided with 4 support beams for supporting the furnace and gear transmission screwdown gears connected with the support beams, and the gear transmission screwdown gears are driven by 1 lifting gear transmission motor through a driving force distribution device.

According to this aspect, since the gear drive screw down device is provided at 4 positions around the roasting furnace, and the rotational force of the 1 drive gear drive motor can be appropriately divided into 4 parts to apply the screw down of the seal portion, the sealing between the roasting furnace main body and the fixed hearth can be appropriately performed uniformly, and the high temperature furnace temperature can be appropriately maintained without being disturbed by the blow-by gas.

The apparatus for baking a cylindrical sputtering target according to claim 3 is characterized in that the heater provided on the inner wall surface of the baking furnace is provided in three or more stages in the height direction of each inner wall of the furnace.

Further, the cylindrical sputtering target of claim 4The apparatus for baking a cylindrical sputtering target according to claim 3, wherein said heater is made of MoSi₂The U-shaped ceramic heater is formed.

The apparatus for baking a cylindrical sputtering target according to claim 5 is characterized in that the heater is provided in a pair with a furnace thermometer according to

claim

3 or 4.

With these configurations, the distribution of the firing temperature in the firing furnace in the height direction can be uniformly adjusted. Specifically, the temperature of the region divided in the height direction is measured by a thermometer provided therein, and the temperature can be controlled to a predetermined temperature by increasing or decreasing the heat output of the heater in the region. Generally, the temperature in the furnace tends to be higher at a higher position than at a lower position, and the temperature can be uniformly brought close to a predetermined temperature by adjusting the heat output of each region. This makes it possible to prevent variation in the firing degree of a long cylindrical sputtering target in the height (length) direction, and contributes to stabilization of quality.

Further, MoSi was used as the heater₂The U-shaped ceramic heater of (1) has sufficient heat resistance and oxidation resistance even at a maximum firing temperature of about 1700 ℃ in an oxygen atmosphere, and thus has a long life, and can exhibit sufficient heating power, and is therefore most suitable for firing a cylindrical sputtering target material to be fired for a long period of time. Further, since the heater is formed in a U-shape, the heater is also resistant to thermal expansion and thermal contraction caused by temperature rise and/or cooling of the heater, and is an optimal heater for each divided region partitioned in the height direction and the peripheral direction in terms of heating strength and heating density. Further, since the heater and the thermometer are arranged in pairs for each zone, the temperature control of each divided zone in the height direction and the peripheral direction can be accurately and accurately performed.

The apparatus for baking a cylindrical sputtering target according to claim 6, wherein the baking furnace main body is provided with one or more gas discharge holes at an upper portion thereof, and a plurality of oxygen blow-in holes in a height direction/a circumferential direction at an inner wall of the furnace from a lower portion of the cylindrical sputtering target placed on the fixed hearth.

With this configuration, the flow path of oxygen in the firing furnace can be made uniform with respect to the cross-sectional direction, and the difference in oxygen concentration between the respective portions can be minimized. Further, since the temperature distribution and/or the oxygen concentration distribution in the furnace can be made uniform, the firing of the long cylindrical sputtering target as the object to be fired can be substantially completely performed homogeneously, the relative density can be stably increased, and the variation in the relative density in the longitudinal direction and/or the cross-sectional direction can be substantially eliminated.

The method of firing a cylindrical sputtering target according to claim 7 is characterized in that the apparatus for firing a cylindrical sputtering target according to any one of claims 1 to 6 is used, wherein a single or a plurality of objects to be fired of a long cylindrical sputtering target having a length of 1.5 to 2m are placed on a fixed hearth in a state of being independent of itself at predetermined intervals, and then, in order to load the fixed hearth into the center of the furnace, a furnace door of the firing furnace is opened, the firing furnace is moved from a waiting position to a firing position, the furnace door is closed, the firing furnace is heated, and the objects to be fired are fired at a high temperature of 1250 to 1700 ℃ for 3 to 30 hours in an oxygen atmosphere to obtain a cylindrical sputtering target.

The method of baking a cylindrical sputtering target according to claim 8 is the method of baking a cylindrical sputtering target according to claim 7, wherein the cylindrical sputtering target is an ITO (tin oxide-indium oxide system) material, an AZO (aluminum oxide-zinc oxide system) material, or an IGZO (indium oxide-gallium oxide-zinc oxide system) material.

The cylindrical sputtering target material is a long cylindrical sputtering target material with the diameter of 150-300 mm, the thickness of the layer of about 10mm and the length of 1.5-2 m. The baking is performed in an oxygen atmosphere at a high temperature of 1450 to 1700 ℃, preferably 1500 to 1600 ℃ in the case of an ITO material, and at a high temperature of 1250 to 1500 ℃, preferably 1300 to 1450 ℃, in the case of an AZO or IGZO material, for 3 to 30 hours, preferably 5 to 10 hours. If this time is too long, the sintered structure may become enlarged and easily broken. The temperature rising rate during the roasting until the target roasting temperature is 100-500 ℃/h, and the temperature falling rate from the target roasting temperature is 10-150 ℃/h.

When the cylindrical sputtering target is baked, the long cylindrical sputtering target can be placed on the fixed hearth in a stable posture by using the baking apparatus for the cylindrical sputtering target, and there is no fear of damaging the cylindrical sputtering target due to the placing operation. Further, since the main firing furnace is used and the oxygen atmosphere is controlled, it is possible to easily provide an appropriate firing temperature and distribution thereof, and thus the same firing temperature can be applied uniformly over the entire length of the object to be fired, and the surface properties and/or relative density free from cracks and the like can be improved, and a stable cylindrical sputtering target can be obtained.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the apparatus and method for baking a cylindrical sputtering target described in claims 1 to 8 of the present invention, since the cylindrical sputtering target as an object to be baked is placed on the fixed hearth during the baking operation and does not move, and instead the baking furnace is moved from the standby position to the baking position to perform baking, the object to be baked is not tilted by the movement, the interval between the object and the heating source is not changed, and there is no fear of damage due to the movement, and the baking quality of the object to be baked is stably obtained. Further, since heaters are provided in a height direction so as to be divided into four directions for heating from the furnace wall, it is easy to adjust the temperature distribution in the furnace height direction to be constant, which contributes to stabilization and improvement of the baking quality of the long cylindrical sputtering target. Further, since the number and positions of the oxygen inflow holes and the oxygen outflow holes for adjusting the oxygen atmosphere are also arranged so as to obtain the same flow path with respect to the object to be fired, the oxygen concentration and the firing temperature can be stably applied to the long cylindrical sputtering target as intended, in addition to the sealing effect of the fixed hearth of the firing furnace.

As described above, according to the baking apparatus and the baking method of the cylindrical sputtering target material of the present invention, the long cylindrical sputtering target can be easily matched with the target quality, and the equipment does not become too large. In addition, the roasting device is: the equipment is compact and has small installation area, no great equipment cost and no air pollution. Further, since it is easy to improve the quality of a cylindrical sputtering target having a long size of 1.5 to 2m, by using the cylindrical sputtering target, it is possible to provide an optimum sputtering target having high use efficiency in the production of a transparent conductive film for a large-sized liquid crystal display device and/or a large-sized photovoltaic device.

Drawings

Fig. 1 is a schematic arrangement diagram of a firing apparatus for a cylindrical sputtering target for carrying out an embodiment of the present invention, and is an arrangement (cross-sectional view) at the time of firing.

Fig. 2 is a configuration (cross-sectional view) at the time of waiting in fig. 1.

Fig. 3 is a schematic cross-sectional view of the a-a arrow view of fig. 1.

Fig. 4 is a schematic cross-sectional view of the view in the direction of the arrow B-B in fig. 1.

Detailed Description

A firing apparatus 1 (hereinafter, referred to as a firing apparatus 1) for a cylindrical sputtering target according to the present invention will be described with reference to fig. 1, 2, 3, and 4.

The cylindrical sputtering target M used in the roasting device and the roasting method of the cylindrical sputtering target is a long cylindrical sputtering target with the diameter of 150-300 mm, the thickness of the layer of about 10mm and the length of 1.5-2M. The material is ITO (tin oxide-indium oxide series) material, AZO (aluminum oxide-zinc oxide series) material or IGZO (indium oxide-gallium oxide-zinc oxide series) material. The baking is performed in an oxygen atmosphere at a high temperature of 1450 to 1700 ℃, preferably 1500 to 1600 ℃ in the case of an ITO material, and at a high temperature of 1250 to 1500 ℃, preferably 1300 to 1450 ℃, in the case of an AZO or IGZO material, for 3 to 30 hours, preferably 5 to 10 hours. The temperature rise speed in the roasting is 100-500 ℃/h, and the temperature drop speed is 10-150 ℃/h.

FIG. 1 is a schematic plan view of a baking apparatus 1, showing the arrangement during baking. The fixed hearth 3 is vertically placed with 4 objects M to be fired as cylindrical sputtering targets, and the fixed hearth 3 is loaded on the firing furnace main body 2 loaded at the center and mounted on the firing furnace traveling device 4 so as to be capable of traveling on the traveling rail 4-3. In the

roasting furnace body

2, 3 surfaces of the shell 2-c and the wall refractory 2-a are provided so as to surround the fixed hearth 3 from four sides of the periphery below the central portion, and the remaining 1 surface has an openable and closable opening and closing door 2-2 to which the refractory 2-a is attached, and the upper portion of the furnace has a furnace ceiling refractory 2-b although not shown, so that the refractory is attached to the inside of the roasting furnace body 2. As the refractory, a shaped or amorphous refractory having high temperature resistance and/or oxidation resistance such as alumina or magnesia is used, and a heat insulating material of a conventional method is used on the furnace shell side. As shown in fig. 3 and 4, the fixed hearth 3 is a quadrangular refractory, and a shaped or amorphous refractory having high temperature resistance and/or oxidation resistance, such as alumina or magnesia, is used. In addition, when the object M is placed upright on the fixed hearth 3, the placing table 3-a is interposed therebetween, so that the firing temperature at the lower end of the object M can be maintained, and the firing quality can be easily maintained. The mounting table 3-a may be made of a refractory having the same properties as the fixed hearth 3.

Fig. 2 shows a state in which the roasting furnace main body 2 of the roasting apparatus 1 is moved from the fixed hearth 3 to a standby state where it is waiting. In this case, when the fixed hearth 3 is in a stripped state and the object to be roasted M is loaded and loaded or the roasted object M is taken out, the surrounding parts do not have any obstacle to the operation, and therefore the operation can be easily and reliably performed. On the other hand, the opening/closing door 2-2 of the roasting furnace main body 2 is in a fully opened state, and the waiting movement from the fixed hearth 3 can be easily performed without any obstacle. Further, when the baking furnace main body 2 is moved, the furnace seal lifting device 5 needs to be operated to release the furnace seal.

Next, the roaster travel device 4 will be described with reference to fig. 3 and 4, and the roaster body 2 is mounted on the travel carriage 4-4 via four support beams 5-5. The traveling carriage 4-4 includes four traveling wheels 4-2 mounted on two traveling rails 4-3 in total, and one of the traveling wheels 4-2 on one side is rotationally driven by a drive gear motor 4-1. The traveling carriage 4-4, although not shown, can travel automatically by a predetermined distance by a proximity switch provided on the traveling rail 4-3 and corresponding to the baking position and the waiting position of the baking furnace main body 2.

Next, the furnace sealing between the roasting furnace body 2 and the fixed hearth 3 will be described with reference to fig. 1, 3, and 4, and when the roasting furnace body 2 moves and travels to the roasting position of fig. 1, stops in a state where the fixed hearth 3 is loaded into the furnace, and then closes the opening/closing door 2-2, a step-like gap is provided between the lower portion of the roasting furnace body 2 and the outer peripheral portion of the fixed hearth 3 as shown in fig. 3 and 4. The furnace body 2 is lowered to close the gap, thereby completing the furnace sealing. By sealing the furnace, the atmosphere is completely prevented from entering the furnace through the sealing portion, or the oxygen atmosphere gas in the furnace is completely prevented from leaking out of the furnace, thereby preventing disturbance of the firing temperature.

As described above, the roasting furnace main body 2 is mounted on the traveling carriage 4-4 via the support beam 5-5 and the gear drive screw-down device 5-4. The furnace sealing lifting device 5 is composed of a driving gear transmission motor 5-1, a driving shaft 2, two driving force distribution devices 5-3 and four gear transmission screw-down devices 5-4. The output of 1 drive gear motor 5-1 is first distributed to the main force axis 5-2 and the orthogonal output axis 5-2 by 1 drive force distribution device 5-3, and one output axis 5-2 is connected to two gear drive screw-down devices 5-4. The other orthogonal output shaft 5-2 is connected to two gear transmission pressing devices 5-4 via the orthogonal output shaft 5-2 by a driving force distribution device 5-3. In this way, in synchronization with the output of the 1 driving gear drive motor 5-1, the four gear drive screw-down devices 5-4 are connected to the support beams 5-5, respectively, so that the roasting furnace main body 2 can be moved in the vertical direction to perform the implementation and release of the furnace seal between the roasting furnace main body 2 and the fixed hearth 3.

As shown in fig. 1, 2, and 3, the opening/closing door 2-2 attached to the roasting furnace main body 2 is provided on the entire furnace side surface of the roasting furnace main body 2 opposite to the standby movement direction. The opening/closing door 2-2 is a single-opening structure that rotates around an opening/closing shaft 2-2-a attached to the furnace shell, and can be fully opened without interfering with the fixed hearth 3 when the roasting furnace main body 2 moves. A door refractories 2-2-c are provided on the inner wall of the opening/closing door 2-2, and a heater 2-d and a furnace thermometer 2-e are provided in a plurality of stages of four stages in the height direction so as to protrude from the door refractories 2-2-c. The opening and closing of the opening and closing door 2-2 may be manual or automatic, but in the case of automatic, it is necessary to interlock with positional information of the roasting furnace main body 2 and the fixed hearth 3.

The baking furnace main body 2 will be described with reference to fig. 1, 2, 3, and 4. The baking furnace main body 2 is used as a baking furnace for baking a long cylindrical sputtering target material having an outer diameter of 150 to 300mm × 1.5 to 2m in an oxygen atmosphere at a set temperature in the range of 1250 to 1700 ℃ for 3 to 30 hours. The furnace size of the roasting furnace main body 2 is about 1.1m square × 2.2m in the case of the present example. In this figure, an embodiment in which 4 long objects to be fired are fired is described, but the present invention is not limited to the number of the objects, and the present invention can be applied to an array in which radiation and convection heat transfer can be equally performed to the objects to be fired, and an array of 2 × N rows. In addition, it is desirable to bake the objects to be baked having the same length as the long ones, because the same baking quality can be easily obtained.

The roasting furnace body 2 has 3 sides of a side shell 2-c, and the remaining 1 side is formed into an outer contour by an opening/closing door 2-2. The furnace shell 2-c and the inner side of the opening and closing door 2-2 are respectively internally stuck with a furnace wall refractory 2-a and a door refractory 2-2-c. The inner wall of the top of the roasting furnace body 2 is formed by a furnace ceiling refractory 2-b. As the refractory, a shaped or amorphous refractory having high temperature resistance and/or oxidation resistance such as alumina or magnesia is used, and a heat insulating material of a conventional method is used on the furnace shell side.

Further, as shown in FIGS. 3 and 4, regarding the heater 2-d, a terminal portion is provided on the furnace shell 2-c or the like, and the heater portion is provided in a shape penetrating the furnace wall refractories 2-a and the door refractories 2-2-c and protruding from the inner surface of the furnace. Further, the heaters 2 to d are provided in four stages in the furnace height direction. Further, the heaters 2-d are made of MoSi₂The resulting U-shaped ceramic heater is excellent, has sufficient heat resistance and oxidation resistance even at a maximum firing temperature of about 1700 ℃ in an oxygen atmosphere, has a long life, and exhibits sufficient heating power, and is therefore most suitable for firing cylindrical sputtering targets M that are fired for a long period of time. Further, since the heater 2-d is formed in a U shape, it is also resistant to thermal expansion and thermal contraction which occur as the heater 2-d is heated and cooled, and the heater 2-d is an optimal shape in terms of heating strength and heating density for each divided region divided in the height direction and the circumferential direction.

Further, a furnace thermometer 2-e can be inserted into the furnace from the furnace shell 2-c at the center of each heater 2-d, and the temperature in the furnace can be measured in a manner to be arranged in a pair with the heater 2-d. This makes it possible to uniformly adjust the distribution of the firing temperature in the furnace height direction in the firing furnace main body 2. Specifically, the temperature of the region divided in the height direction is measured by the thermometer 2-e installed in the furnace, and the temperature can be controlled to a predetermined temperature by increasing or decreasing the heat output of the heater 2-d in the region. In general, regarding the temperature in the furnace, the tendency for the temperature of a high location to become higher compared to the temperature of a low location can be made to approach the predetermined temperature uniformly by adjusting the respective heat outputs of the respective regions. This makes it possible to prevent variation in the firing degree of the long cylindrical sputtering target M in the height (length) direction, and contributes to stabilization of quality. As the furnace thermometer 2-e, a well-known platinum-rhodium thermocouple can be used.

As shown in fig. 3 and 4, the furnace interior of the baking furnace main body 2 is maintained in an oxygen atmosphere, and in order to maintain the baking temperature at a predetermined value, a single or a plurality of gas discharge holes 2-g are provided in the upper portion of the baking furnace main body 2, and a plurality of oxygen injection holes (not shown) are provided in the height direction/circumferential direction from the lower portion of the cylindrical sputtering target M placed on the fixed hearth and from the furnace inner walls 2-b, 2-2-c. With this configuration, the oxygen flow path in the furnace main body 2 is uniform in the cross-sectional direction, and the difference in oxygen concentration between the respective portions can be minimized. Further, since the temperature distribution and/or the oxygen concentration distribution in the furnace can be made uniform, the firing of the long cylindrical sputtering target M as the object to be fired can be substantially completely performed homogeneously, the relative density can be stably increased, and the variation in the relative density in the longitudinal direction and/or the cross-sectional direction can be substantially eliminated.

A firing method using the cylindrical sputtering target firing device of the present invention will be described with reference to fig. 1, 2, 3, and 4. As for the cylindrical sputtering target, a material selected from an ITO (tin oxide-indium oxide system) material, an AZO (aluminum oxide-zinc oxide system) material, or an IGZO (indium oxide-gallium oxide-zinc oxide system) material may be used. The cylindrical sputtering target can be produced by adding water, a binder and a dispersant to the above raw material oxide powder, mixing them to form a slurry, granulating the slurry into a granulated powder by a spray dryer or the like, and molding the granulated powder by a cold isostatic press (CIP method) or the like. The cylindrical sputtering target is a long cylindrical sputtering target with the diameter of 150-300 mm, the thickness of the layer of 10mm and the length of 1.5-2 m.

The method of firing the cylindrical sputtering target is performed as follows. A cylindrical sputtering target can be obtained by placing a single or a plurality of (4 in the figure) cylindrical sputtering target materials M having a length in the range of 1.5 to 2M on a fixed hearth 3 in a state of being self-standing with a predetermined interval, opening an opening/closing door 2-2 of a roasting furnace main body 2 so that the fixed hearth 3 is placed in the center of the furnace, moving the roasting furnace main body 2 from a waiting position to a roasting position, closing the opening/closing door 2-2, raising the temperature of the roasting furnace main body 2, and roasting the target materials M at a high temperature of 1250 to 1700 ℃ for 3 to 30 hours in an oxygen atmosphere.

The baking is performed in an oxygen atmosphere at a high temperature of 1450 to 1700 ℃, preferably 1500 to 1600 ℃ in the case of an ITO material, and at a high temperature of 1250 to 1500 ℃, preferably 1300 to 1450 ℃, in the case of an AZO or IGZO material, for 3 to 30 hours, preferably 5 to 10 hours. If this time is too long, the sintered structure may become large and may easily break. The temperature rising speed of the roasting process to the target roasting temperature is 100-500 ℃/h, and the temperature reduction speed after the roasting is finished is 10-150 ℃/h.

The baked cylindrical sputtering target is attached to a back tube having a magnetic field generating device and a cooling device built therein by soldering, and magnetron sputtering is performed, and deposition of a target oxide is performed on a substrate by this sputtering, whereby a transparent conductive film used for a liquid crystal display element, a solar cell, or the like can be reliably and stably manufactured.

Industrial applicability

The method can be applied to the field of roasting of cylindrical sputtering targets and the field of high-temperature roasting treatment of long-size objects in oxidizing and reducing atmosphere.

Description of the reference numerals

1: cylindrical sputtering target material roasting device

2: roasting furnace main body 2-a: furnace wall refractories 2-b: furnace ceiling refractory

2-c: furnace shell 2-d: heaters 2-e: furnace thermometer

2-f: oxygen inlet 2-g: oxygen outflow port 2-2: opening and closing door

2-2-a: opening and closing shaft 2-2-b: locking rotating handle 2-2-c: door fire-resistant article

3: fixed hearth 3-a: placing table

4: roasting furnace running device 4-1: drive gear transmission motor 4-2: running wheel

4-3: running track 4-4: traveling carriage

5: the furnace sealing lifting device 5-1 drives a gear transmission motor 5-2: drive shaft

5-3: drive force distribution device 5-4: gear transmission screw-down device 5-5: supporting beam

M: the object to be fired (cylindrical sputtering target).

Claims

1. A cylindrical sputtering target roasting device is a cylindrical sputtering target roasting device with a length of 1.5-2 m, and is characterized by comprising:

a fixed hearth for vertically placing the object to be fired of the long cylindrical sputtering target;

a roasting furnace main body which is disposed so as to enclose the fixed hearth and in which a plurality of heaters are provided on an inner wall surface of the furnace;

a roasting furnace traveling device that mounts the roasting furnace body on a traveling carriage and can travel the roasting furnace body to a waiting position along a track while being separated from a position where the fixed hearth is enclosed,

a furnace door is provided on one side of the main body of the baking furnace, the furnace door can be opened and closed without interference when the fixed hearth is wrapped, a sealing part for preventing gas leakage is provided between the lower part of the furnace shell of the baking furnace and the peripheral part of the fixed hearth, and a furnace sealing lifting device for pressing and sealing the sealing part by moving the main body of the baking furnace downward during baking is provided.

2. The cylindrical sputter target firing apparatus according to claim 1, wherein the furnace sealing elevating means is constituted in such a manner that: the lower part of the roasting furnace body is provided with 4 supporting beams for supporting the furnace and a gear transmission screw-down device connected with the supporting beams, and the gear transmission screw-down devices are driven by 1 lifting gear transmission motor through a driving distribution device.

3. The apparatus for baking a cylindrical sputtering target according to claim 1 or 2, wherein the heater provided on the inner wall surface of the baking furnace is divided into three or more stages in the height direction of each inner wall of the furnace.

4. The apparatus for firing a cylindrical sputter target according to claim 3, wherein said heater is made of MoSi₂The U-shaped ceramic heater is formed.

5. The apparatus for firing a cylindrical sputtering target according to claim 3, wherein the heater is provided in a pair with a furnace thermometer.

6. The apparatus for firing a cylindrical sputtering target according to claim 4, wherein the heater is provided in a pair with a furnace thermometer.

7. The baking apparatus for a cylindrical sputtering target according to claim 1 or 2, wherein the baking furnace main body is provided with one or more gas discharge holes at an upper portion, and a plurality of oxygen blow-in holes are provided in a furnace inner wall in a height direction or a circumferential direction from a lower portion of the cylindrical sputtering target placed on the fixed hearth.

8. A method of baking a cylindrical sputtering target, characterized in that the apparatus for baking a cylindrical sputtering target according to any one of claims 1 to 7 is used, wherein a single or a plurality of objects to be baked of a long cylindrical sputtering target having a length of 1.5 to 2m are placed on a fixed hearth in a state of being self-standing with a predetermined interval therebetween, and then, in order to load the fixed hearth into the center of a furnace, a furnace door of the furnace is opened, the furnace is moved from a waiting position to a baking position, the furnace door is closed, the temperature of the furnace is raised, and the objects to be baked are baked at a high temperature of 1250 to 1700 ℃ for 3 to 30 hours in an oxygen atmosphere to obtain a cylindrical sputtering target.

9. The method of claim 8, wherein the cylindrical sputtering target is an ITO material, an AZO material, or an IGZO material.