Powder film deposition apparatus and powder film deposition method

Abstract

To provide a powder film deposition apparatus capable of cracking a powder inside the powder film deposition apparatus.SOLUTION: In a powder film deposition apparatus 100, a film deposition step of depositing a film by reacting a surface of a powder with a raw material gas introduced under a vacuum condition heated in a predetermined film deposition temperature range, and a cracking step of cracking an aggregate of a powder particle at a temperature lower than the film deposition temperature range are performed. A chamber 50 is arranged in a vacuum chamber 200, and the raw material gas flows upward in a vertical direction through a powder storage part 55 in the film deposition step. An exhaust block 40 exhausts the raw material gas from an exhaust port 41 arranged on a side wall. A cracking unit 30 is configured such that the cracking unit is raised in the film deposition step and is retracted upward in the chamber 50, and is lowered in the cracking step and a crushing head 36 goes into the powder storage part 55. A control part 80 heats the chamber 50 to the film deposition temperature range in the film deposition step, lifts the cracking unit 30, cools the chamber 50 to a cracking possible temperature in the cracking step, and lowers the cracking unit 30.SELECTED DRAWING: Figure 1

Description

【Technical Field】 【0001】 The present invention relates to a powder film forming apparatus and a powder film forming method. 【Background Art】 【0002】 Conventionally, a film forming apparatus and a film forming method for forming a film by reacting a raw material gas on the surface of an object to be processed under vacuum conditions are known. For example, Patent Document 1 discloses a vacuum film forming apparatus and a film forming method for forming a film on the surface of a substrate by an ALD (atomic layer deposition) method in which two types of raw material gases are alternately introduced and reacted. Further, Patent Document 2 discloses a powder film forming apparatus and a film forming method for forming a film on the surface of a powder by a plasma CVD method. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2012-184482 【Patent Document 2】 Japanese Patent Application Laid-Open No. 2022-008248 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 When performing ALD film formation on a powder material, film formation is performed by supplying a gas into a chamber in which the powder is confined. Here, the operation of loosening the aggregate of powder particles is called "disaggregation". By repeating the process of exposing the aggregated portion of the powder after film formation by disaggregation and performing film formation again, it becomes possible to form a film on a powder material with a smaller particle diameter. However, since a general disaggregation process is performed in the atmosphere, it is not suitable for being combined with and implemented with ALD film formation or the like performed in a vacuum. 【0005】 Furthermore, ALD film deposition is performed under high-temperature vacuum conditions, for example, by heating to a deposition temperature range of around 300°C. When the raw material gas comes into contact with the structure of the crushing mechanism heated to the deposition temperature range, unwanted film deposition occurs on the surface of that structure, resulting in loss of raw material gas and contamination of the powder material with by-products. For this reason, it has been difficult to crush powder inside a powder deposition apparatus under high-temperature vacuum conditions. 【0006】 This invention was created in view of the above points, and its purpose is to provide a powder film deposition apparatus and a powder film deposition method that can crush powder inside the powder film deposition apparatus. [Means for solving the problem] 【0007】 The powder film deposition apparatus of the present invention performs a film deposition step in which one or more raw material gases introduced from below in a vertical direction react with the surface of the powder under vacuum conditions heated to a predetermined film deposition temperature range to form a film, and a crushing step in which aggregates of powder particles are broken up at a temperature lower than the film deposition temperature range. 【0008】 This powder film deposition apparatus comprises a vacuum chamber housing (20), a chamber (50), a heater (51), an exhaust block (40), a crushing unit (30), a unit lifting mechanism (25), an expandable / contractable member (24), and a control unit (80). 【0009】 The vacuum chamber housing has a vacuum chamber (200) inside and a raw material gas inlet (56) at the bottom. The chamber (50) is located inside the vacuum chamber and has a powder storage section (55) containing the powder to be processed. During the film formation process, the raw material gas introduced from the inlet flows vertically upward through the powder storage section. The heater (51) heats the chamber. 【0010】 The exhaust block (40) is connected to the top of the chamber, and the raw material gas is exhausted from the exhaust port (41) provided on the side wall. 【0011】 The crushing unit (30) has a crushing head (36) at its lower end that rotates to crush the powder. The crushing unit is configured to rise and retract above the chamber during the film formation process, and to descend during the crushing process so that the crushing head enters the powder storage section. 【0012】 The unit lifting mechanism (25) raises and lowers the crushing unit. The cylindrical expandable member (24) is fixed at one end to the crushing unit and expands and contracts in accordance with the raising and lowering of the crushing unit while maintaining a vacuum inside. 【0013】 The control unit (80) controls the temperature of the chamber, the raising and lowering operation of the unit lifting mechanism, and the crushing operation of the crushing unit. Preferably, during the film deposition process, the control unit raises the temperature of the chamber to the film deposition temperature range and raises the crushing unit. Also, during the crushing process, the control unit lowers the temperature of the chamber to a crushing temperature lower than the film deposition temperature range, where film deposition on the crushing head is suppressed, and lowers the crushing unit. 【0014】 In the powder film deposition apparatus of the present invention, the chamber temperature is reduced to a temperature at which crushing is possible during the crushing process. Therefore, the temperature at which the crushing head, which has entered the powder, is heated is kept below the temperature at which crushing is possible. Even if the raw material gas comes into contact with the crushing head, which has been retracted to the upper part of the chamber during the subsequent film deposition process, film deposition on the crushing head is suppressed. Thus, crushing of the powder inside the powder film deposition apparatus is possible. 【0015】 The present invention relates to a powder film formation method which involves a film formation step in which one or more raw material gases introduced from below in a vertical direction react with the surface of the powder under vacuum conditions heated to a predetermined film formation temperature range to form a film, and a crushing step in which aggregates of powder particles are broken up at a temperature lower than the film formation temperature range, both of which are performed inside a single powder film formation apparatus (100). 【0016】 The powder film forming apparatus has a crushing unit (30) provided with a crushing head (36) for crushing powder at its lower end, and the crushing unit (30) can be moved up and down by a unit lifting mechanism (25). Further, a cylindrical telescopic member (24) having one end fixed to the crushing unit is configured to expand and contract following the up and down movement of the crushing unit while maintaining a vacuum inside. 【0017】 In the film forming process, the chamber (50) having a powder storage part (55) arranged in the vacuum chamber (20) and containing the powder to be processed is heated to the film forming temperature range, and the crushing unit rises and retreats above the chamber. The raw material gas introduced from the inlet (56) flows upward in the vertical direction through the powder storage part and is exhausted from the exhaust port (41) provided on the side wall of the exhaust block (40) connected to the upper part of the chamber. In the crushing process, the chamber is cooled down to a temperature at which crushing is possible, which is lower than the film forming temperature range and at which film formation on the crushing head is suppressed. Also, the crushing unit descends, the crushing head enters the powder storage part and rotates to crush the powder. 【0019】 In the powder film forming method of the present invention, the same operational effects as those of the above-described powder film forming apparatus can be obtained. This powder film forming method is synonymous with the "method for manufacturing the formed powder", and acts such as using and transferring the formed powder are included in the implementation of the invention. 【Brief Description of the Drawings】 【0020】 [Figure 1] Schematic diagram showing the configuration of the powder film forming apparatus in its original position according to an embodiment. [Figure 2] Schematic diagram showing the operation in the film forming process of the powder film forming apparatus of FIG. 1. [Figure 3] Schematic diagram showing the operation in the crushing process of the powder film forming apparatus of FIG. 1. [Figure 4] (a) Schematic diagram of the powder storage part of the chamber in the film forming process, (b) Schematic diagram of the powder storage part of the chamber in the crushing process. [Figure 5] Front view (a) and bottom view (b) of the crushing head. [Figure 6]A diagram for explaining the state change of powder particles by repeating the film-forming process and the crushing process. [Figure 7] Time chart of a powder film-forming method according to an embodiment. [Figure 8] Flow chart of a powder film-forming method according to an embodiment. [Figure 9] Time chart of a powder film-forming method of a comparative example. 【Mode for Carrying Out the Invention】 【0021】 A powder film-forming apparatus and a powder film-forming method according to an embodiment of the present invention will be described based on the drawings. This powder film-forming apparatus is an apparatus that forms a film by reacting one or more raw material gases on the surface of powder under vacuum conditions heated to a predetermined film-forming temperature range. In the present embodiment, an example applied to the ALD (atomic layer deposition) method in which two types of precursors are alternately introduced as raw material gases is shown. For example, the powder of the ALD method is carbon or silica, and metal oxides such as alumina are used as precursors. In batch processing, one batch of powder is set in the powder film-forming apparatus. 【0022】 Conventionally, it has been difficult to perform "crushing" to loosen aggregates of powder particles inside a powder film-forming apparatus under high-temperature vacuum conditions. Therefore, in the present embodiment, an object is to provide a powder film-forming apparatus 100 capable of performing both a film-forming process and a crushing process inside one apparatus. The crushing process is performed at a temperature lower than the film-forming temperature range. By integrating a crushing mechanism into a vacuum film-forming apparatus, space saving and cost reduction of equipment can be achieved. 【0023】 Referring to FIGS. 1 to 3, the configuration of a powder film-forming apparatus 100 according to an embodiment will be described. FIG. 1 shows the in-situ apparatus configuration. FIG. 2 shows the operations in the film-forming process, and FIG. 3 shows the operations in the crushing process. The vertical direction of the paper surface of FIGS. 1 to 3 is the vertical direction. "Above" and "below" in the following description mean "above in the vertical direction" and "below in the vertical direction". In the film-forming process, the raw material gas introduced into the chamber 50 from below flows upward. 【0024】 The powder film deposition apparatus 100 includes a vacuum chamber housing 20, a chamber 50, a heater 51, a reflector 52, an exhaust block 40, a crushing unit 30, a unit lifting mechanism 25, an expandable / contractable member 24, a control unit 80, and the like. 【0025】 First, the configuration of the film deposition process will be explained. The vacuum chamber housing 20 is a housing enclosed by a bottom plate 21, a top plate 22, and side plates 23, and forms a vacuum chamber 200 inside. The vacuum chamber 200 is connected to a vacuum pump (not shown) via an exhaust passage. When the exhaust valve provided in the exhaust passage is opened, the pressure in the vacuum chamber 200 is reduced from atmospheric pressure to vacuum. For convenience, the low-pressure state of vacuum according to the film deposition conditions will be referred to as "vacuum". An inlet 56 for raw material gas and purge gas (N2, etc.) is provided at the bottom of the vacuum chamber housing 20. Hereafter, references to purge gas may be omitted as appropriate. 【0026】 Chamber 50 is placed in the vacuum chamber 200. Within the vacuum chamber housing 20, the inside of Chamber 50, through which the raw material gas for the film deposition process passes, is maintained at a higher vacuum level than the outside of Chamber 50. If the outside of Chamber 50 is considered "low vacuum," then the inside of Chamber 50 corresponds to "medium vacuum." Chamber 50 has a cylindrical shape, with the diameter at the top being larger than the diameter at the bottom. 【0027】 Chamber 50 has a powder storage section 55 at its lower part, which contains a batch of powder to be processed, and constitutes a fluidized bed ALD film deposition apparatus. As shown in Figure 2, in the film deposition process, the raw material gas (and purge gas) introduced from the inlet 56 flows upward through the powder storage section 55. See Figure 4 for further details. 【0028】 The heater 51 is positioned to surround the radially outer side of the chamber 50 and heats the chamber 50. For example, the heater 51 is constructed by laying a sheath heater on a plate. The reflector 52 is positioned radially outside the heater 51 and, as indicated by the dashed arrow, reflects the radiant heat from the heater 51 towards the chamber 50. This prevents parts other than the chamber 50, such as the crushing mechanism, from being unnecessarily overheated by the radiant heat from the heater 51. A temperature sensor 53, such as a thermocouple, detects the temperature of the chamber 50. 【0029】 The exhaust block 40 is cylindrical and connected to the top of the chamber 50. The raw material gas is exhausted from an exhaust port 41 provided on the side wall of the exhaust block 40. Figure 1 shows one exhaust port 41, but two exhaust ports may be provided to separate and recover two types of precursors using a switching valve. As shown in Figure 2, in the film formation process, the raw material gas flows upwards from the chamber 50, then changes direction horizontally within the exhaust block 40 and heads towards the exhaust port 41. 【0030】 A thermal expansion absorbing member 44, for example made of a bellows, is provided between the top plate 22 of the vacuum chamber housing 20 and the upper end of the exhaust block 40. The thermal expansion absorbing member 44 isolates the internal space of the chamber 50 and exhaust block 40 through which the raw material gas passes from the space outside, while absorbing the thermal expansion caused by the temperature rise of the chamber 50 and exhaust block 40. In addition, by preventing the exhaust block 40 from directly contacting the top plate 22 of the vacuum chamber housing 20, heat transfer from the chamber 50 to the top plate 22 is inhibited. 【0031】 Next, the configuration of the crushing mechanism installed under high-temperature vacuum conditions will be described. The crushing unit 30 has a crushing head 36 at its lower end that rotates to crush the powder. The crushing head 36 has a pin mill type structure, which will be described in detail later with reference to Figure 5. As shown in Figures 2 and 3, the crushing unit 30 is configured to rise and retract above the chamber 50 during the film formation process, and to descend during the crushing process so that the crushing head 36 enters the powder storage section 55. 【0032】 Preferably, when the crushing unit 30 rises, the crushing head 36 is positioned above the height of the exhaust port 41 so as to avoid the exhaust path of the raw material gas. As will be described later, in addition to the chamber temperature being lowered to a crushing temperature during the crushing process, this is advantageous in suppressing unnecessary film formation on the surface of the crushing head 36 by making it difficult for the raw material gas to come into contact with the crushing head 36. 【0033】 The top of the crushing unit 30 is provided with a cylindrical isolation case 38 that separates the atmospheric side space Ra, which is open to the atmosphere, from the vacuum side space Rv, which is connected to the vacuum chamber 200. The unit lifting mechanism 25 moves the crushing unit 30 up and down by rotating a ball screw 252 with a motor 251, for example, to move the upper end position of the isolation case 38. 【0034】 The cylindrical expandable member 24 is fixed at one end to the crushing unit 30 and expands and contracts in accordance with the raising and lowering of the crushing unit 30 while maintaining a vacuum inside. In this embodiment, the expandable member 24 is composed of a bellows, with its lower end fixed to the top plate 22 of the vacuum chamber housing 20 and its upper end fixed to the isolation case 38. The space inside the isolation case 38 becomes the atmospheric space Ra, and the annular space between the outer wall of the isolation case 38 and the expandable member 24 becomes the vacuum space Rv. As the expandable member 24 expands and contracts, the volume of the vacuum space Rv changes. 【0035】 The crushing unit 30 includes, in addition to the crushing head 36 and isolation case 38 described above, a crushing motor 31, a coupling 32, a shaft 34, a bearing 35, a magnetic seal 33, etc., which are provided along the rotation axis Z. The crushing motor 31 is located in the atmospheric space Ra inside the isolation case 38 and outputs rotational power. The coupling 32 connects the output shaft of the crushing motor 31 to the shaft 34. The shaft 34 is located in the vacuum space Rv and rotates when the rotational power of the crushing motor 31 is transmitted to it. As a result, the crushing head 36 fixed to the tip of the shaft 34 rotates and crushes the powder. The bearing 35 rotatably supports the shaft 34. 【0036】 Here, if air leaks from the atmospheric space Ra to the vacuum space Rv through the diameter clearance in the rotation support portion of the shaft 34, the vacuum level of the vacuum chamber 200 will decrease. In this embodiment, a magnetic seal 33 is provided to seal the diameter clearance with magnetic fluid as a means of ensuring airtightness. The seal is obtained by holding the magnetic fluid in the gap between the rotating shaft and the pole piece along the magnetic flux lines formed by the magnet. Note that the heat resistance temperature of commercially available magnetic seals is about 130°C, which is the lowest heat resistance among the components of the crushing mechanism. Therefore, cooling water may be flowed around the magnetic seal 33 to prevent overheating. 【0037】 In this embodiment, at least the control unit 80 controls the energization of the heater 51, the lifting and lowering operation of the unit lifting mechanism 25, and the crushing operation of the crushing unit 30. Regarding the temperature control of the chamber 50, the control unit 80 in this embodiment controls the energization of the heater 51 by PID control or the like so that the temperature detected by the feedback temperature sensor 53 approaches the target value, and after reaching the target value, so that the detected temperature maintains the target value. In addition, the same control unit 80 may also control the opening and closing of the exhaust valve, the timing of the introduction of purge gas and raw material gas in the film formation process, etc., or a different control unit may be responsible for these functions. 【0038】 During the film deposition process, the control unit 80 energizes the heater 51 to raise the chamber 50 to the film deposition temperature range (e.g., target value 300°C) and raises the crushing unit 30 using the unit lifting mechanism 25. During the crushing process, the control unit 80 also stops the power supply to the heater 51 to lower the chamber 50 to the crushing temperature (e.g., 100°C) and lowers the crushing unit 30 using the unit lifting mechanism 25. The crushing temperature is set lower than the film deposition temperature range to suppress film deposition on the crushing head 36. 【0039】 Here, even if the temperature of the crushing head 36 is within the film deposition temperature range, the crushing operation itself is still possible. However, if the crushing head 36 enters the powder storage section 55 heated to 300°C and performs crushing, for example, the crushing head 36 will receive heat from the powder and frictional heat, and its temperature may rise to nearly 300°C. The same applies to the lower part of the shaft 34 connected to the crushing head 36, and the same interpretation applies below. When the crushing unit 30 is raised in the subsequent film deposition process to move the crushing head 36 above the chamber 50, if the exhausted raw material gas comes into contact with the high-temperature crushing head 36, unwanted film deposition will occur on the surface of the crushing head 36. 【0040】 Therefore, the control unit 80 of this embodiment lowers the chamber temperature during the crushing process to a crushing temperature, thereby keeping the temperature of the crushing head 36, which receives heat from the powder and frictional heat during the crushing operation, below the crushing temperature. Consequently, the formation of unnecessary film on the surface of the crushing head 36 is suppressed. 【0041】 Next, with reference to Figures 4 to 6, the mechanisms of the film formation process on the powder surface and the powder particle crushing process will be explained. Figure 4 shows a fluidized bed type film formation apparatus with a simplified chamber shape. In the film formation process shown in Figure 4(a), the raw material gas (precursor) and purge gas are introduced from the lower inlet 56 and flow out to the upper part of the chamber 50 through the powder storage section 55 where the powder particles P are contained. With each cycle of "purge → introduce precursor A → purge → introduce precursor B", one atomic or molecular layer is formed on the surface of the powder particles P. The gas flowing out of the chamber 50 is not directed upwards where the crushing head 36 is retracted, but is exhausted to the side. 【0042】 In the crushing process shown in Figure 4(b), the crushing head 36 enters the powder storage section 55 and rotates to loosen the aggregates of powder particles P. Here, as shown in Figure 5, the crushing head 36 has multiple pins 362 erected on the upper and lower surfaces of the disc 361. When the disc 361 rotates around the rotation axis Z, the multiple pins 362 collide with the powder particles P, causing the powder particles P to be crushed. 【0043】 Referring to Figure 6, the changes in the state of powder particles P due to repeated film formation and crushing processes will be explained. In the first film formation process, a first layer of film F1 is formed on the surface of the aggregates of powder particles P. In the subsequent crushing process, the aggregates are dispersed, and the unformed film portions are exposed. The dispersed powder particles P re-aggregate due to intermolecular forces (van der Waals forces). In the second film formation process, a second layer of film F2 is formed on the surface of the re-aggregated aggregates. At this time, the film is formed over the entire surface of the powder particles P, including the overlapping portions of the first layer of film F1 and the second layer of film F2, and the portions where only the second layer of film F2 is formed. 【0044】 By repeating the film formation process and the crushing process in this manner, the proportion of unformed areas exposed can be reduced, improving the film formation efficiency (coverage rate) for small-particle-sized powders. While it is theoretically possible to repeat the film formation process in a vacuum deposition apparatus and the crushing process in the open atmosphere, as will be discussed later as a comparative example, this is inefficient in terms of time and energy, and presents safety challenges. In contrast, this embodiment achieves the installation of a crushing mechanism under high-temperature vacuum conditions through the configuration of the crushing unit 30, the unit lifting mechanism 25, the expandable member 24, etc., enabling efficient and safe repetition of the film formation process and the crushing process within a single powder deposition apparatus 100. 【0045】 Referring to the time chart in Figure 7 and the flowchart in Figure 8, a powder film deposition method using the powder film deposition apparatus 100 of this embodiment will be described. In the flowchart, the symbol "S" represents a step. Here, an example is shown in which the method is applied to an ALD film deposition method using two types of precursors A and B as raw material gases. 【0046】 In the preparation phase, one batch of powder for batch processing is placed in the chamber 50. Then, at time t01, the exhaust valve is opened, and at time t02, the vacuum chamber pressure is reduced from atmospheric pressure to vacuum. At S1 in the flowchart, the vacuum chamber pressure is reduced to vacuum. 【0047】 At time t02, the control unit 80 starts supplying power to the heater 51 and heats the chamber 50. The chamber 50 is then heated from room temperature (e.g., 20°C) to a target value in the film deposition temperature range (e.g., 300°C). At time t10, the chamber temperature reaches the target value in the film deposition temperature range. In this way, in S2, the control unit 80 raises the temperature of the chamber 50 to the film deposition temperature range. 【0048】 The first film deposition process (S3) is performed from time t10 to t14. One film deposition process consists of the following four steps, repeated M times (M=4 in the illustrated example). For example, one purge takes 20 seconds, and one precursor introduction takes 10 seconds. [1] N2 purge [2] Introduction of Precasa A [3] N2 purge [4] Introduction of Precasa B 【0049】 After the completion of the 1st to 3rd cycles at times t11, t12, and t13, and following the 4th cycle, a final N2 purge is performed, and one film deposition process (S3) is completed at time t14. In S4, it is determined whether the film deposition process has reached the set number of times N (for example, N=3). If the result in S4 is NO, the process proceeds to S5-S8, which includes the decomposition process and the processes before and after it. 【0050】 When the first film deposition process is completed at time t14, the control unit 80 stops supplying power to the heater 51 and cools the chamber 50 down to a temperature at which crushing is possible (e.g., 100°C) (S5). Once the chamber 50 has cooled down to a temperature at which crushing is possible, the control unit 80 lowers the crushing unit 30 at time t15 and rotates the crushing motor 31 at time t16 to perform the first crushing process (S6). 【0051】 When the predetermined crushing process is completed, the control unit 80 stops the rotation of the crushing motor 31 at time t17 and raises the crushing unit 30 (S7). When the crushing unit 30 is raised, the control unit 80 energizes the heater 51 at time t18 and raises the chamber 50 back to the film formation temperature range (S8). 【0052】 The second film deposition process (S3) is performed from time t20 to t24, and the second decomposition process and the processes before and after it (S5 to S8) are performed from time t24 to t28. Furthermore, the third film deposition process (S3) is performed from time t30 to t34. The operations at each time from t20 to t34 are the same as the operations at the corresponding times t10 to t18 in the first film deposition and decomposition processes, so their explanation is omitted. 【0053】 After the third film deposition process, in S4 it is determined that the film deposition process has reached the set number of N times, and the process proceeds to S9. At time t34, the control unit 80 stops the power supply to the heater 51, allowing the chamber 50 to cool down to room temperature (S9). Once the chamber 50 has cooled down to room temperature, at time t99 the exhaust valve is closed, and the vacuum chamber pressure returns to atmospheric pressure (S10). Then, the processed batch of powder is removed from the powder deposition apparatus 100. 【0054】 As described above, in the powder film formation method of this embodiment, the film formation process and the crushing process are repeated alternately multiple times under vacuum conditions for each batch of powder in batch processing. Therefore, the film formation efficiency (coverage rate) for powders with small particle sizes can be improved. 【0055】 The effects of this embodiment will be explained in comparison with the comparative example powder deposition method shown in Figure 9. In the comparative example, a powder deposition apparatus that performs only the vacuum deposition process is used, and the crushing process is performed in the atmosphere outside the apparatus. In Figure 9, the time symbols corresponding to those in Figure 7 are used. The conditions for the deposition process from t10 to t14 and t20 to t24 are the same as in this embodiment. If the time axis is represented on the same scale as in Figure 7, the third deposition process in the comparative example goes out of frame on the page. 【0056】 In the comparative example, when the first film deposition process is completed at time t14, the power to the heater 51 is stopped and the chamber 50 cools down. When the chamber 50 cools down to room temperature at time t15z, the exhaust valve is closed and the vacuum chamber pressure returns to atmospheric pressure. The powder batch after film deposition is removed from the apparatus and the first crushing process (times t16-t17) is carried out in the atmosphere outside the apparatus. 【0057】 The crushed powder batch is set back into the powder deposition apparatus, the exhaust valve is opened, and the vacuum chamber pressure becomes a vacuum. At time t18z, the chamber 50 is heated again from room temperature to the deposition temperature range, and at time t20, the second deposition process begins. At time t24, when the second deposition process is completed, the powder batch is removed from the apparatus using the same procedure, and the second crushing process (times t26-t27) is carried out in the atmosphere outside the apparatus. The crushed powder batch is set back into the apparatus, and the third deposition process begins again using the same procedure. 【0058】 As described above, in the comparative example, the process is time-consuming because the temperature difference between the film formation temperature range and room temperature is repeatedly reduced and increased each time the film formation process and the crushing process are switched. Pressure stabilization time is also required each time the vacuum chamber 200 is depressurized. Including the time required for removing and setting up the powder batch, a huge amount of time is taken, and a great deal of energy is wasted. Furthermore, performing the crushing process of highly active powder materials such as metallic aluminum in an atmospheric environment is undesirable from a safety standpoint. 【0059】 In contrast, in this embodiment, each time the film formation process and the crushing process are switched, the temperature difference from the film formation temperature range to the crushing temperature is repeatedly reduced and increased. From this viewpoint, it is preferable to set the crushing temperature as high as possible within a range that can suppress unnecessary film formation on the crushing head 36. In some cases, the disadvantage of some film formation on the crushing head 36 may be tolerated, and the optimal crushing temperature may be set by a trade-off with shortening the cooling time and heating time. 【0060】 Furthermore, in this embodiment, since the vacuum chamber 200 is maintained under vacuum throughout the entire process, the time required for pressure stabilization during subsequent depressurization of the vacuum chamber can be shortened compared to the comparative example. Additionally, the time required for removing and resetting powder batches can be reduced, and the workspace required for the external crushing process is eliminated. Moreover, energy loss associated with the cooling and heating of the chamber and the pressure fluctuations in the vacuum chamber is reduced. In addition, safety is improved because the crushing process of highly active powder materials is not performed in an atmospheric environment. 【0061】 (Other embodiments) (a) The powder film deposition apparatus of the present invention is not limited to the ALD method, in which two types of precursors are alternately introduced as raw material gases, but may also be used in the CVD method, in which one type of raw material gas is introduced and deposition is carried out on the powder surface. 【0062】 (b) The configuration for ensuring airtightness between the atmospheric space Ra and the vacuum space Rv in the rotational power transmission section of the crushing unit 30 is not limited to the use of a magnetic seal 33. For example, the output shaft of the crushing motor 31 in the atmospheric space Ra and the shaft 34 in the vacuum section Rv may be mechanically separated by a partition wall, and rotational power may be transmitted non-contact by a magnetic coupling. A magnetic coupling is known as a functional component that transmits torque without leakage in liquid pumps and the like. 【0063】 (c) The crushing unit 30 is not limited to a configuration in which it is isolated in an atmospheric space and a vacuum space by an isolation case 38. If the crushing motor 31 can be placed in the vacuum space, the crushing unit 30 may be configured only in the vacuum space. 【0064】 (d) The expandable member 24 is not limited to a bellows-shaped bellows, but may be composed of, for example, a multi-cylinder structure. The unit lifting mechanism 25 is not limited to the ball screw structure illustrated in Figure 1, etc., but may be composed of a cylinder that moves the rod forward and backward. 【0065】 (e) In the powder film formation method of the above embodiment, the film formation efficiency (coverage rate) for small particle size powders can be improved by repeating the film formation process and the crushing process alternately multiple times under vacuum conditions for one batch of powder in batch processing. However, the crushing process may be performed only once, such as "1st film formation process - crushing process - 2nd film formation process". 【0066】 (f) The temperature control of the chamber 50 by the control unit 80 is not limited to a method of controlling the energization of the heater 51 by feeding back the temperature detected by the temperature sensor 53 installed in the chamber 50. For example, the temperature detected by another part that is correlated with the chamber temperature may be fed back, or feedforward control may be performed based on the amount of heat generated by the heater 51 and the energization time. 【0067】 The present invention is not limited in any way to the embodiments described above, and can be implemented in various forms without departing from its spirit. [Explanation of symbols] 【0068】 100...Powder film forming equipment, 200... Vacuum chamber, 20... Vacuum chamber enclosure, 24...Extendable member, 25...Unit lifting mechanism, 30... Crushing unit, 36... Crushing head, 40... Exhaust block, 41... Exhaust port, 50... Chamber, 51... Heater, 55...Powder storage section, 56...Inlet, 80...Control unit.

Claims

[Claim 1] A powder film forming apparatus comprising a film forming step in which one or more raw material gases introduced from vertically below are reacted to the surface of a powder under vacuum conditions heated to a predetermined film forming temperature range to form a film, and a crushing step in which aggregates of powder particles are broken up at a temperature lower than the film forming temperature range, A vacuum chamber enclosure (20) has a vacuum chamber (200) formed inside and a raw material gas inlet (56) provided at the bottom, The vacuum chamber is arranged and has a powder storage section (55) containing the powder to be processed, and the raw material gas introduced from the inlet in the film formation process flows vertically upward through the powder storage section, A heater (51) for heating the chamber, An exhaust block (40) is connected to the upper part of the chamber, and the raw material gas is exhausted from an exhaust port (41) provided on the side wall, A crushing unit (30) is provided with a crushing head (36) at its lower end that rotates to crush the powder, and is configured to rise during the film formation process and retract above the chamber, and to descend during the crushing process so that the crushing head enters the powder storage section, A unit lifting mechanism (25) for raising and lowering the crushing unit, A cylindrical expandable member (24) is fixed at one end to the crushing unit and expands and contracts in accordance with the raising and lowering of the crushing unit while maintaining a vacuum inside, A control unit (80) that controls the temperature of the chamber, the lifting operation of the unit lifting mechanism, and the crushing operation of the crushing unit, A powder film deposition apparatus equipped with [a specific feature]. [Claim 2] The control unit, During the film formation process, the chamber is heated to the film formation temperature range, and the crushing unit is raised. The powder film forming apparatus according to claim 1, wherein during the crushing process, the chamber is cooled to a crushing temperature lower than the film formation temperature range, such that film formation on the crushing head is suppressed, and the crushing unit is lowered. [Claim 3] The aforementioned crushing unit is An isolation case (38) that separates the atmospheric space open to the atmosphere from the vacuum space communicating with the vacuum chamber, The aforementioned space on the atmospheric side is arranged and includes a crushing motor (31) that outputs rotational power, A shaft (34) is arranged in the vacuum space and rotates when the rotational power of the crushing motor is transmitted to it, The crushing head (36) is fixed to the tip of the shaft, The powder film forming apparatus according to claim 2, including the following: [Claim 4] The aforementioned crushing unit is The powder film forming apparatus according to claim 3, further comprising a magnetic seal (33) that seals the diameter clearance in the rotation support portion of the shaft with a magnetic fluid. [Claim 5] The heater is provided so as to surround the radially outer side of the chamber. The powder film forming apparatus according to any one of claims 2 to 4, wherein a reflector (52) is provided radially outward of the heater to reflect radiant heat from the heater towards the chamber. [Claim 6] A powder film formation method comprising a film formation step in which one or more raw material gases introduced from vertically below under vacuum conditions heated to a predetermined film formation temperature range react with the surface of a powder to form a film, and a crushing step in which aggregates of powder particles are broken up at a temperature lower than the film formation temperature range, all performed inside a single powder film formation apparatus (100), The aforementioned powder film forming apparatus is A crushing unit (30) having a crushing head (36) for crushing powder at its lower end is movable up and down by a unit lifting mechanism (25). A cylindrical expandable member (24), one end of which is fixed to the crushing unit, is configured to expand and contract in accordance with the raising and lowering of the crushing unit while maintaining a vacuum inside. In the aforementioned film formation process, The chamber (50), which is located in the vacuum chamber (20) and has a powder storage section (55) containing the powder to be processed, is heated to the film formation temperature range, and the crushing unit rises and retracts above the chamber. The raw material gas introduced from the inlet (56) flows vertically upward through the powder storage section and is exhausted from the exhaust port (41) provided on the side wall of the exhaust block (40) connected to the upper part of the chamber. In the aforementioned crushing process, A powder film formation method comprising: cooling the chamber to a crushing temperature lower than the aforementioned film formation temperature range, thereby suppressing film formation on the crushing head; lowering the crushing unit; and the crushing head entering the powder storage section and rotating to crush the powder. [Claim 7] The powder film formation method according to claim 6, wherein the film formation step and the crushing step are repeated alternately multiple times under vacuum conditions for one batch of powder in batch processing.

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