Powder film forming apparatus and powder film forming method

Abstract

To provide a powder film forming apparatus and a powder film forming method for facilitating film formation on powder.SOLUTION: A chamber 10 of a powder film forming apparatus 5 has an internal space 104 including an upper space 106 and a lower space 108. A stirring section 30, by rotating about an axis, moves powder stored in the lower space 108 from the lower space 108 to the upper space 106. A control section 70 is configured such that: when exhaust of gas in the internal space 104 is stopped and a source gas is supplied to the upper space 106 and then supply of the source gas is stopped, the stirring section 30 is rotated to adsorb the source gas onto the powder; when gas in the internal space 104 is exhausted, rotation of the stirring section 30 is stopped; and when exhaust of gas in the internal space 104 is stopped and a reaction gas is supplied to the upper space 106 and then supply of the reaction gas is stopped, the stirring section 30 is rotated to cause the source gas adsorbed onto the powder to react with the reaction gas to form a film on the powder.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a powder film forming apparatus and a powder film forming method for forming a film from powder.

Background Art

[0002] Conventionally, as described in Patent Document 1, a method for forming a film from powder is known. In this powder film forming method, powder is distributed in a rotating vacuum chamber. Further, the rotating vacuum chamber rotates in a first direction along the axis in the axial direction of the rotating vacuum chamber. Further, the gas in the rotating vacuum chamber is exhausted through the vacuum port in the rotating vacuum chamber. Further, the paddle assembly rotates in a second direction so that a plurality of paddles orbit a drive shaft. Further, process gas is injected into the powder through a plurality of gas outlets located on the plurality of paddles. Further, the plurality of gas outlets are located in the powder bed formed by the powder, and the process gas penetrates through the powder held in the rotating vacuum chamber.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the powder film-forming method described in Patent Document 1, due to the centrifugal force caused by the rotation of the rotary vacuum chamber, the powder is held outside in the direction perpendicular to the axis of the rotary vacuum chamber within the rotary vacuum chamber. Further, the process gas from the plurality of gas outlets is injected toward the outside in the direction perpendicular to the axis of the rotary vacuum chamber, and thus is injected toward the held powder. However, due to the injected process gas, the powder outside in the direction perpendicular to the axis of the rotary vacuum chamber scatters from the outside to the inside within the rotary vacuum chamber. As a result, the scattered powder flows to the exhaust port. For this reason, it is difficult to form a film on the powder.

[0005] An object of the present disclosure is to provide a powder film-forming apparatus and a powder film-forming method that facilitate film formation on powder.

Means for Solving the Problems

[0006] The invention according to claim 1 is a powder film-forming apparatus for forming a film from powder, comprising a chamber (10) having an internal space (104) including an upper space (106) which is a space on the top side in the vertical direction and a lower space (108) which is a space on the bottom side in the vertical direction and in which the powder is stored, an exhaust unit (20) for reducing the pressure of the internal space and exhausting the gas in the internal space, a stirring unit (30) for rotating about an axis (Or) to move the powder stored in the lower space from the lower space to the upper space, a raw material gas supply unit (40) for supplying a raw material gas to the upper space, a reaction gas supply unit (50) for supplying a reaction gas to the upper space, and a control unit (70) for controlling the exhaust of the gas in the internal space by the exhaust unit, the rotation of the stirring unit, the supply of the raw material gas from the raw material gas supply unit, and the supply of the reaction gas from the reaction gas supply unit. The control unit rotates the stirring unit when stopping the exhaust of the gas in the internal space and stopping the supply of the raw material gas after supplying the raw material gas to the upper space, so as to adsorb the raw material gas to the powder; stops the rotation of the stirring unit when exhausting the gas in the internal space; stops the exhaust of the gas in the internal space, rotates the stirring unit when stopping the supply of the reaction gas after supplying the reaction gas to the upper space, and reacts the raw material gas adsorbed on the powder with the reaction gas, thereby forming a film on the powder.

[0007] Further, the invention according to claim 10 is a powder film-forming method for forming a film from powder, comprising a chamber (10) having an internal space (104) including an upper space (106) which is the space on the top side in the vertical direction and a lower space (108) which is the space on the bottom side in the vertical direction and in which the powder is stored, an exhaust section (20) for reducing the pressure of the internal space and exhausting the gas in the internal space, a stirring section (30) for rotating about an axis (Or) to move the powder stored in the lower space from the lower space to the upper space, a source gas supply section (40) for supplying source gas to the upper space, and a reaction gas supply section (50) for supplying reaction gas to the upper space. After stopping the exhaust of the gas in the internal space and supplying the source gas to the upper space and then stopping the supply of the source gas, the stirring section is rotated to adsorb the source gas to the powder. When exhausting the gas in the internal space, the rotation of the stirring section is stopped. After stopping the exhaust of the gas in the internal space and supplying the reaction gas to the upper space and then stopping the supply of the reaction gas, the stirring section is rotated to react the source gas adsorbed to the powder with the reaction gas, thereby forming a film on the powder.

[0008] By the rotation of the stirring section, although the powder scatters, it moves from the lower space to the upper space. Further, source gas and reaction gas are respectively supplied to the upper space. Therefore, gas adsorption to the powder and reaction of the gas adsorbed to the powder become easier. Also, when causing gas adsorption to the powder and reaction of the gas adsorbed to the powder, the exhaust of the gas in the internal space is stopped. For this reason, the powder adsorbed with gas and the film-formed powder are difficult to be discharged. Thus, film formation on the powder becomes easier.

[0009] Note that the reference numerals in parentheses attached to each component etc. show an example of the correspondence relationship between the component etc. and the specific components etc. described in the embodiments described later.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals, and the description thereof will be omitted.

[0012] (First Embodiment) The powder film forming apparatus of the present embodiment is an apparatus for forming a film on powder using ALD, which facilitates film formation on the powder. The powder to be formed into a film is composed of, for example, carbon. Note that ALD is an abbreviation for Atomic Layer Deposition, which is atomic layer deposition.

[0013] Specifically, as shown in FIG. 1, the powder film forming apparatus 5 includes a chamber 10, a vacuum pump 20, an exhaust pipe 22, an exhaust valve 24, a stirring unit 30, a drive unit 32, a source gas supply unit 40, a source gas pipe 42, and a source gas valve 44. Further, the powder film forming apparatus 5 includes a reaction gas supply unit 50, a reaction gas pipe 52, a reaction gas valve 54, a purge gas supply unit 60, a purge gas pipe 62, a purge gas valve 64, and a control unit 70.

[0014] The chamber 10 is formed in a cylindrical container shape from a metal such as stainless steel. Also, the axis of the chamber 10 extends in a direction orthogonal to the vertical direction here. Further, the chamber 10 has a chamber upper part 100, a powder container 102, and an internal space 104.

[0015] The chamber upper part 100 is the upper part of the chamber 10 in the vertical direction. Also, the chamber upper part 100 forms an upper space 106. The upper space 106 is the upper space of the space inside the chamber 10 in the vertical direction.

[0016] The powder container 102 corresponds to the bottom of the chamber and is the lower part of the chamber 10 in the vertical direction. Further, the powder container 102 is connected to the chamber upper part 100 in the vertical direction and is fixed to the chamber upper part 100 by a fixing member such as a screw (not shown). Also, the powder container 102 detaches from the chamber upper part 100 when the fixing member comes off. Further, the powder container 102 forms a lower space 108. The lower space 108 is the lower space of the space inside the chamber 10 in the vertical direction. Also, powder is stored in the lower space 108. Further, the internal space 104 is formed by the lower space 108 and the upper space 106.

[0017] The vacuum pump 20 corresponds to an exhaust part and is connected to the chamber upper part 100 via an exhaust pipe 22. Further, the vacuum pump 20 reduces the pressure of the internal space 104 and exhausts the gas in the internal space 104. The exhaust valve 24 is a control valve or a solenoid valve and is attached to the exhaust pipe 22.

[0018] The stirring part 30 moves the powder stored in the lower space 108 from the lower space 108 to the upper space 106 by rotating about the rotation axis Or. Specifically, the stirring part 30 has a shaft part 300 and a plate part 302.

[0019] The shaft portion 300 includes the rotation axis Or and extends in the direction of the rotation axis Or. Here, the direction of the rotation axis Or coincides with the axial direction of the chamber 10, and the rotation axis Or extends in a direction orthogonal to the vertical direction. Therefore, the shaft portion 300 extends in a direction orthogonal to the vertical direction. Further, most of the shaft portion 300 is disposed in the internal space 104. Also, the end of the shaft portion 300 protrudes from the chamber 10.

[0020] The plate portion 302 is connected to the shaft portion 300 and extends in a direction orthogonal to the rotation axis Or. Further, the plate portion 302 is formed in a rectangular plate shape here. Note that the shape of the plate portion 302 is not limited to a rectangular shape, and may be, for example, a polygonal shape, an arc shape, an elliptical arc shape, etc. Also, the shape of the plate portion 302 may be a mesh shape or the like in which the holes are larger than the particle size of the powder.

[0021] The drive unit 32 is a motor or the like and is connected to the end of the shaft portion 300 that protrudes from the chamber 10. Further, the drive unit 32 rotates the shaft portion 300. Thereby, the plate portion 302 connected to the shaft portion 300 rotates about the rotation axis Or. As a result, the powder stored in the lower space 108 is agitated. For this reason, the powder moves from the lower space 108 to the upper space 106. Also, the shape of the powder container 102 is formed along the rotation orbit of the stirring unit 30 so that the rotation of the stirring unit 30 and the stirring of the powder by the stirring unit 30 are facilitated. Here, since the plate portion 302 is rectangular, the rotation orbit of the stirring unit 30 is circular. Therefore, here, the powder container 102 is formed in an arc shape centered on the rotation axis Or as shown in FIG. 2.

[0022] Returning to FIG. 1, the raw material gas supply unit 40 stores the raw material gas by having a cylinder or the like. The raw material gas is, for example, TMA. TMA is trimethylaluminum. Further, the raw material gas supply unit 40 is connected to the upper part 100 of the chamber via a raw material gas pipe 42. Furthermore, the raw material gas supply unit 40 supplies the raw material gas to the upper space 106 via the raw material gas pipe 42. The raw material gas valve 44 is a regulating valve or a solenoid valve and is attached to the raw material gas pipe 42.

[0023] The reaction gas supply unit 50 stores the reaction gas by having a cylinder or the like. The reaction gas is, for example, water vapor. Further, the reaction gas supply unit 50 is connected to the upper part 100 of the chamber via a reaction gas pipe 52. Furthermore, the reaction gas supply unit 50 supplies the reaction gas to the upper space 106 via the reaction gas pipe 52. The reaction gas valve 54 is a regulating valve or a solenoid valve and is attached to the reaction gas pipe 52.

[0024] The purge gas supply unit 60 stores the purge gas by having a cylinder or the like. The purge gas is a gas that expels the raw material gas and the reaction gas from the internal space 104 and is, for example, nitrogen. Further, the purge gas supply unit 60 is connected to the upper part 100 of the chamber via a purge gas pipe 62. Furthermore, the purge gas supply unit 60 supplies the purge gas to the upper space 106 via the purge gas pipe 62. The purge gas valve 64 is a regulating valve or a solenoid valve and is attached to the purge gas pipe 62.

[0025] The control unit 70 is mainly composed of a microcomputer or the like, and includes a CPU, a ROM, a flash memory, a RAM, an I / O, a drive circuit, and a bus line connecting these components. Further, the control unit 70 executes a program stored in the ROM of the control unit 70. Thereby, the control unit 70 controls the evacuation of the gas in the internal space 104 by the vacuum pump 20 by controlling the opening and closing of the exhaust valve 24. Further, the control unit 70 controls the rotation of the stirring unit 30 by controlling the drive unit 32. Also, the control unit 70 controls the supply of the raw material gas from the raw material gas supply unit 40 by controlling the opening and closing of the raw material gas valve 44. Further, the control unit 70 controls the supply of the reaction gas from the reaction gas supply unit 50 by controlling the opening and closing of the reaction gas valve 54. Also, the control unit 70 controls the supply of the purge gas from the purge gas supply unit 60 by controlling the opening and closing of the purge gas valve 64. And, by these controls, the powder is formed into a film. Note that the film formation on the powder by these controls will be described later.

[0026] As described above, the powder film forming apparatus 5 of the first embodiment is configured. Next, the film formation on the powder by the execution of the program of the control unit 70 will be described with reference to the flowchart of FIG. 3 and the time chart of FIG. 4. Note that the program of the control unit 70 is executed, for example, at the following time. The following time means that, as shown in FIG. 5, when the chamber 10 or the like is prepared, the powder is put into the powder container 102, and a switch (not shown) for executing the program of the control unit 70 is pressed in a state where the powder container 102 is connected to the upper part 100 of the chamber. In FIG. 5, the powder is depicted with a dot pattern in order to clarify the powder.

[0027] In step S100 of FIG. 3, the control unit 70 outputs a signal for opening the exhaust valve 24 to the exhaust valve 24. As a result, the exhaust valve 24 opens. For this reason, the gas in the internal space 104 is exhausted, and the pressure in the internal space 104 is reduced. At this time, the exhaust flow rate of the vacuum pump 20 and the like are adjusted so that the powder stored in the lower space 108 is not discharged. Also, at this time, the stirring unit 30 is stopped. The raw material gas valve 44 is closed. The reaction gas valve 54 is closed. The purge gas valve 64 is closed. Further, at this time, the control unit 70 may heat the chamber 10 by controlling a heater (not shown) or the like so that the temperature of the chamber 10 becomes a predetermined temperature in order to facilitate the adsorption of the gas described later.

[0028] Also, when the pressure in the internal space 104 is reduced to a predetermined pressure, the control unit 70 outputs a signal for closing the exhaust valve 24 to the exhaust valve 24. As a result, the exhaust valve 24 closes.

[0029] In step S102 following step S100, the control unit 70 outputs a signal for opening the raw material gas valve 44 to the raw material gas valve 44. As a result, the raw material gas valve 44 is open during the period from time t1 to time t2 in FIG. 4. For this reason, the raw material gas from the raw material gas supply unit 40 is supplied to the upper space 106 through the raw material gas pipe 42.

[0030] In step S104 following step S102, the control unit 70 outputs a signal for rotating the drive unit 32 to the drive unit 32. As a result, during the period from time t1 to time t2, the drive unit 32 rotates, and thus the stirring unit 30 rotates. When the stirring unit 30 rotates, the powder stored in the powder container 102 moves from the lower space 108 to the upper space 106. The raw material gas supplied to the upper space 106 is adsorbed by the powder that has moved to the upper space 106. Note that during the period from time t1 to time t2, the exhaust valve 24 is closed. The reaction gas valve 54 is closed. The purge gas valve 64 is closed.

[0031] Thereafter, the control unit 70 outputs a signal for closing the raw material gas valve 44 to the raw material gas valve 44. As a result, at time t2, the raw material gas valve 44 closes. Therefore, the supply of the raw material gas from the raw material gas supply unit 40 stops.

[0032] Also, in the period from time t2 to time t3, the control unit 70 continues to output a signal for rotating the drive unit 32. As a result, the raw material gas filled in the upper space 106 is adsorbed to the powder that has moved to the upper space 106. Note that in the period from time t2 to time t3, the exhaust valve 24 is closed. The raw material gas valve 44 is closed. The reaction gas valve 54 is closed. The purge gas valve 64 is closed.

[0033] Then, at time t3, the control unit 70 outputs a signal for stopping the rotation of the drive unit 32 to the drive unit 32. As a result, the rotation of the drive unit 32 stops, and thus the rotation of the stirring unit 30 stops. Also, due to gravity, the powder to which the raw material gas is adsorbed is stored in the lower space 108.

[0034] In step S106 following step S104, the control unit 70 outputs a signal for opening the exhaust valve 24 to the exhaust valve 24. As a result, in the period from time t4 to time t5, the exhaust valve 24 is open. Therefore, the raw material gas remaining in the upper space 106 and the gas generated by the adsorption reaction are exhausted. Note that at this time, the exhaust flow rate of the vacuum pump 20 and the like are adjusted so that the powder stored in the lower space 108 is not discharged. Also, in the period from time t4 to time t5, the stirring unit 30 is stopped. The raw material gas valve 44 is closed. The reaction gas valve 54 is closed. The purge gas valve 64 is closed.

[0035] Thereafter, the control unit 70 outputs a signal for closing the exhaust valve 24 to the exhaust valve 24. As a result, at time t5, the exhaust valve 24 closes.

[0036] In step S108 following step S106, the control unit 70 outputs a signal for opening the purge gas valve 64 to the purge gas valve 64. As a result, during the period from time t6 to time t7, the purge gas valve 64 is open. For this reason, the purge gas from the purge gas supply unit 60 is supplied to the upper space 106 through the purge gas pipe 62. Thereby, the raw material gas remaining in the upper space 106 without being exhausted and the gas generated by the adsorption reaction are diluted.

[0037] In step S110 following step S108, the control unit 70 outputs a signal for rotating the drive unit 32 to the drive unit 32. As a result, during the period from time t6 to time t7, the drive unit 32 rotates, and thereby the stirring unit 30 rotates. When the stirring unit 30 rotates, the powder stored in the powder container 102 moves from the lower space 108 to the upper space 106. The powder that has moved to the upper space 106 is exposed to the purge gas supplied to the upper space 106. For this reason, the raw material gas remaining between the powder particles and the gas generated by the adsorption reaction are diluted. Thereby, an unintended reaction with the reaction gas described later is suppressed. Note that during the period from time t6 to time t7, the exhaust valve 24 is closed. The raw material gas valve 44 is closed. The reaction gas valve 54 is closed.

[0038] Thereafter, the control unit 70 outputs a signal for closing the purge gas valve 64 to the purge gas valve 64. As a result, at time t7, the purge gas valve 64 closes. For this reason, the supply of the purge gas from the purge gas supply unit 60 stops.

[0039] Furthermore, in the period from time t7 to time t8, the control unit 70 continues to output a signal for rotating the drive unit 32. As a result, the powder that has moved to the upper space 106 is exposed to the purge gas filled in the upper space 106. For this reason, the raw material gas remaining between the powder particles and the gas generated by the adsorption reaction are diluted. Thereby, an unintended reaction with the reaction gas described later is suppressed. Note that in the period from time t7 to time t8, the exhaust valve 24 is closed. The raw material gas valve 44 is closed. The reaction gas valve 54 is closed. The purge gas valve 64 is closed.

[0040] Then, at time t8, the control unit 70 outputs a signal for stopping the rotation of the drive unit 32 to the drive unit 32. As a result, when the rotation of the drive unit 32 stops, the rotation of the stirring unit 30 stops. Also, due to gravity, the powder adsorbed with the raw material gas is stored in the lower space 108.

[0041] In step S112 following step S110, the control unit 70 outputs a signal for opening the exhaust valve 24 to the exhaust valve 24. As a result, in the period from time t9 to time t10, the exhaust valve 24 is open. For this reason, the purge gas and the diluted gas filled in the upper space 106 are exhausted. Note that at this time, the exhaust flow rate of the vacuum pump 20 and the like are adjusted so that the powder stored in the lower space 108 is not discharged. Also, in the period from time t9 to time t10, the stirring unit 30 is stopped. The raw material gas valve 44 is closed. The reaction gas valve 54 is closed. The purge gas valve 64 is closed.

[0042] Thereafter, the control unit 70 outputs a signal for closing the exhaust valve 24 to the exhaust valve 24. As a result, at time t10, the exhaust valve 24 closes.

[0043] In step S114 following step S112, the control unit 70 outputs a signal for opening the reaction gas valve 54 to the reaction gas valve 54. As a result, the reaction gas valve 54 is open during the period from time t11 to time t12. Therefore, the reaction gas from the reaction gas supply unit 50 is supplied to the upper space 106 through the reaction gas pipe 52.

[0044] In step S116 following step S114, the control unit 70 outputs a signal for rotating the drive unit 32 to the drive unit 32. As a result, during the period from time t11 to time t12, the drive unit 32 rotates, and thus the stirring unit 30 rotates. When the stirring unit 30 rotates, the powder stored in the powder container 102 moves from the lower space 108 to the upper space 106. The source gas adsorbed on the powder that has moved to the upper space 106 reacts with the reaction gas supplied to the upper space 106. As a result, a film of one atomic layer is formed on the powder. Note that during the period from time t11 to time t12, the exhaust valve 24 is closed. The source gas valve 44 is closed. The purge gas valve 64 is closed.

[0045] Thereafter, the control unit 70 outputs a signal for closing the reaction gas valve 54 to the reaction gas valve 54. As a result, at time t12, the reaction gas valve 54 closes. Therefore, the supply of the reaction gas from the reaction gas supply unit 50 stops.

[0046] Also, during the period from time t12 to time t13, the control unit 70 continues to output a signal for rotating the drive unit 32. As a result, the source gas adsorbed on the powder that has moved to the upper space 106 reacts with the reaction gas filling the upper space 106. As a result, a film of one atomic layer is formed on the powder. Note that during the period from time t12 to time t13, the exhaust valve 24 is closed. The source gas valve 44 is closed. The reaction gas valve 54 is closed. The purge gas valve 64 is closed.

[0047] Then, at time t13, the control unit 70 outputs a signal to the drive unit 32 to stop the rotation of the drive unit 32. As a result, the rotation of the stirring unit 30 stops due to the stop of the rotation of the drive unit 32. Further, due to gravity, the powder formed into a film is stored in the lower space 108.

[0048] In step S118 following step S116, the control unit 70 outputs a signal to the exhaust valve 24 to open the exhaust valve 24. As a result, the exhaust valve 24 is open during the period from time t14 to time t15. For this reason, the reaction gas remaining in the upper space 106 and the gas generated by the reaction with the reaction gas are exhausted. At this time, the exhaust flow rate of the vacuum pump 20 and the like are adjusted so that the powder stored in the lower space 108 is not discharged. Further, during the period from time t14 to time t15, the stirring unit 30 is stopped. The raw material gas valve 44 is closed. The reaction gas valve 54 is closed. The purge gas valve 64 is closed.

[0049] Thereafter, the control unit 70 outputs a signal to the exhaust valve 24 to close the exhaust valve 24. As a result, the exhaust valve 24 closes at time t15.

[0050] In step S120 following step S118, the control unit 70 outputs a signal to the purge gas valve 64 to open the purge gas valve 64. As a result, the purge gas valve 64 is open during the period from time t16 to time t17. For this reason, the purge gas from the purge gas supply unit 60 is supplied to the upper space 106 through the purge gas pipe 62. As a result, the reaction gas remaining in the upper space 106 and the gas generated by the reaction with the reaction gas that were not completely exhausted are diluted.

[0051] In step S122 following step S120, the control unit 70 outputs a signal to rotate the drive unit 32 to the drive unit 32. As a result, during the period from time t16 to time t17, the drive unit 32 rotates, causing the stirring unit 30 to rotate. When the stirring unit 30 rotates, the powder stored in the powder container 102 moves from the lower space 108 to the upper space 106. The powder that has moved to the upper space 106 is exposed to the purge gas supplied to the upper space 106. For this reason, the reaction gas remaining between the formed powder particles and the gas generated by the reaction with the reaction gas are diluted. As a result, an unintended reaction with the raw material gas to be introduced next is suppressed. Note that during the period from time t16 to time t17, the exhaust valve 24 is closed. The raw material gas valve 44 is closed. The reaction gas valve 54 is closed.

[0052] Thereafter, the control unit 70 outputs a signal to close the purge gas valve 64 to the purge gas valve 64. As a result, at time t17, the purge gas valve 64 closes. For this reason, the supply of the purge gas from the purge gas supply unit 60 stops.

[0053] Furthermore, during the period from time t17 to time t18, the control unit 70 continues to output a signal to rotate the drive unit 32. As a result, the powder that has moved to the upper space 106 is exposed to the purge gas filled in the upper space 106. For this reason, the reaction gas remaining between the formed powder particles and the gas generated by the reaction with the reaction gas are diluted. As a result, an unintended reaction with the raw material gas to be introduced next is suppressed. Note that during the period from time t17 to time t18, the exhaust valve 24 is closed. The raw material gas valve 44 is closed. The reaction gas valve 54 is closed. The purge gas valve 64 is closed.

[0054] Then, at time t18, the control unit 70 outputs a signal to stop the rotation of the drive unit 32 to the drive unit 32. As a result, when the rotation of the drive unit 32 stops, the rotation of the stirring unit 30 stops. Also, due to gravity, the formed powder is stored in the lower space 108.

[0055] In step S124 following step S122, the control unit 70 outputs a signal for opening the exhaust valve 24 to the exhaust valve 24. As a result, the exhaust valve 24 is open during the period from time t19 to time t20. For this reason, the purge gas and the diluted gas filled in the upper space 106 are exhausted. At this time, the exhaust flow rate of the vacuum pump 20 and the like are adjusted so that the powder stored in the lower space 108 is not discharged. Also, during the period from time t19 to time t20, the stirring unit 30 is stopped. The raw material gas valve 44 is closed. The reaction gas valve 54 is closed. The purge gas valve 64 is closed.

[0056] Thereafter, the control unit 70 outputs a signal for closing the exhaust valve 24 to the exhaust valve 24. As a result, the exhaust valve 24 closes at time t20.

[0057] In step S126 following step S124, the control unit 70 counts up the film formation number N by adding 1 to the film formation number N. The film formation number N is the number of times the series of processes from step S102 to step S124 have been performed.

[0058] In step S128 following step S126, the control unit 70 determines whether or not the film formation number N counted in step S126 is equal to or greater than the threshold value N_th. The threshold value N_th is set by experiments, simulations, etc. so that the film thickness formed on the powder becomes the desired film thickness.

[0059] When the film formation number N is less than the threshold value N_th, since the film thickness formed on the powder has not become the desired film thickness, the process of the control unit 70 returns to step S102. Further, the processes from step S102 to step S126 are repeated until the film formation number N reaches the threshold value N_th, that is, until the film thickness formed on the powder becomes the desired film thickness.

[0060] Further, when the number of film formation times N is equal to or greater than the threshold value N_th, since the film thickness formed on the powder is the desired film thickness, the process of the control unit 70 ends. Therefore, the film formation on the powder is completed.

[0061] Here, as described above, the powder formed by the powder film forming apparatus 5 of the present embodiment is composed of carbon. The source gas is TMA. The reaction gas is water vapor. Therefore, the film formed on the powder is composed of alumina. The powder on which this alumina is formed is used, for example, as a raw material for manufacturing a battery or the like. Further, in a battery manufactured using the powder on which this alumina is formed as a raw material, the electrode performance of the battery is improved.

[0062] As described above, film formation on the powder is performed by executing the program of the control unit 70. Next, the powder film forming apparatus 5 will be described in terms of ease of film formation on the powder.

[0063] In the powder film forming apparatus 5 of the present embodiment, the stirring unit 30 rotates about the rotation axis Or to move the powder stored in the lower space 108 from the lower space 108 to the upper space 106. Also, as at time t2 in FIG. 4, the control unit 70 stops exhausting the gas in the internal space 104, supplies the source gas to the upper space 106, and then stops supplying the source gas. At this time, the control unit 70 rotates the stirring unit 30 to adsorb the source gas to the powder. Further, during the period from time t4 to time t5, the period from time t9 to time t10, the period from time t14 to time t15, and the period from time t19 to time t20, the control unit 70 exhausts the gas in the internal space 104. At this time, the control unit 70 stops the rotation of the stirring unit 30. Also, as at time t12, the control unit 70 stops exhausting the gas in the internal space 104, supplies the reaction gas to the upper space 106, and then stops supplying the reaction gas. At this time, the control unit 70 rotates the stirring unit 30 to react the reaction gas with the source gas adsorbed on the powder, thereby forming a film on the powder.

[0064] Due to the rotation of the stirring unit 30, although the powder scatters, it moves from the lower space 108 to the upper space 106. Further, the raw material gas and the reaction gas are respectively supplied to the upper space 106. Therefore, gas adsorption to the powder and reaction of the gas adsorbed to the powder are facilitated. Also, when gas adsorption to the powder and reaction of the gas adsorbed to the powder are carried out, the exhaust of the gas in the internal space 104 is stopped. For this reason, the powder adsorbed with gas and the film-formed powder are difficult to be discharged. Thus, film formation on the powder is facilitated.

[0065] Also, here, in the powder film formation method described in Patent Document 1, since the powder flows to the exhaust port, the recovery rate of the film-formed powder is low.

[0066] On the other hand, in the powder film forming apparatus 5 of the present embodiment, even if the film-formed powder scatters, it is stored in the lower space 108 by gravity. For this reason, in film formation on small and light powder, recovery is also easy.

[0067] Also, the powder film forming apparatus 5 of the first embodiment also exhibits the effects described below.

[0068] [1-1] As at time t7 and time t17, when the control unit 70 stops the exhaust of the gas in the internal space 104, the control unit 70 supplies the purge gas to the upper space 106. Further, when the control unit 70 stops the supply of the purge gas after supplying the purge gas to the upper space 106, the control unit 70 rotates the stirring unit 30.

[0069] When the stirring unit 30 rotates, the powder stored in the powder container 102 moves from the lower space 108 to the upper space 106. The powder that has moved to the upper space 106 is exposed to the purge gas supplied to the upper space 106. For this reason, the raw material gas remaining between the powder particles and the gas generated by the adsorption reaction are diluted. Thereby, an unintended reaction with the reaction gas later is suppressed. Also, the reaction gas remaining between the film-formed powder particles and the gas generated by the reaction with the reaction gas are diluted. Thereby, an unintended reaction with the raw material gas introduced next time is suppressed.

[0070] [1-2] The powder container 102 is shaped along the rotation orbit of the stirring unit 30. Here, as shown in FIG. 2, the powder container 102 has an arc shape centered on the rotation axis Or.

[0071] As a result, compared with the case where the powder container 102 has corners due to being formed in a polygonal shape, it is less likely for powder to be buried in the corners of the powder container 102. For this reason, due to the rotation of the stirring unit 30, the powder stored in the powder container 102 is likely to scatter, and thus is likely to move from the lower space 108 to the upper space 106. Therefore, the generation of powder that is not formed into a film is suppressed.

[0072] (Second Embodiment) In the second embodiment, the processing of the control unit 70 is different from that of the first embodiment. Otherwise, it is the same as the first embodiment.

[0073] Here, in the first embodiment, the control unit 70 supplies the raw material gas during the period from time t1 to time t2. The control unit 70 supplies the purge gas during the period from time t6 to time t7. The control unit 70 supplies the reaction gas during the period from time t11 to time t12. The control unit 70 supplies the purge gas during the period from time t16 to time t17. Also, the control unit 70 rotates the stirring unit 30 during the periods from time t1 to time t2, from time t6 to time t7, from time t11 to time t12, and from time t16 to time t17.

[0074] In contrast, in the second embodiment, as shown in the time chart of FIG. 6, the control unit 70 stops the rotation of the stirring unit 30 instead of rotating the stirring unit 30 during the period from time t1 to time t2. Further, the control unit 70 stops the rotation of the stirring unit 30 instead of rotating the stirring unit 30 during the period from time t6 to time t7. Furthermore, the control unit 70 stops the rotation of the stirring unit 30 instead of rotating the stirring unit 30 during the period from time t11 to time t12. Also, the control unit 70 stops the rotation of the stirring unit 30 instead of rotating the stirring unit 30 during the period from time t16 to time t17. Therefore, in the second embodiment, the control unit 70 rotates the stirring unit 30 immediately after the supply of each gas is stopped.

[0075] As described above, the control unit 70 in the powder film forming apparatus 5 of the second embodiment performs the process. Also in this second embodiment, the same effects as those of the first embodiment are achieved.

[0076] (Third Embodiment) In the third embodiment, the forms of the chamber 10 and the stirring unit 30 are different from those in the first embodiment. Other than this, it is the same as the first embodiment.

[0077] Specifically, as shown in FIG. 7, instead of the axis of the chamber 10 extending in a direction orthogonal to the vertical direction, it extends in the vertical direction. Further, the upper part 100 of the chamber includes an upper surface 110. The upper surface 110 is located on the sky side and forms an upper space 106. Furthermore, the powder container 102 includes a bottom surface 112. The bottom surface 112 is located on the ground side and forms a lower space 108. Also, the side surface of the powder container 102 is inclined so that the size of the lower space 108 decreases as it goes from the boundary between the upper part 100 of the chamber and the powder container 102 toward the bottom surface 112. For this reason, the size of the bottom surface 112 is smaller than the size of the upper surface 110. Furthermore, the length of the bottom surface 112 in the direction orthogonal to the vertical direction is smaller than the length of the upper surface 110 in the direction orthogonal to the vertical direction.

[0078] Further, instead of the rotation axis Or of the stirring unit 30 extending in a direction orthogonal to the vertical direction, it extends in the vertical direction. For this reason, the shaft portion 300 extends in the vertical direction. Furthermore, the stirring unit 30 has a spiral portion 304 instead of the plate portion 302.

[0079] The spiral portion 304 is connected to the shaft portion 300. Further, the spiral portion 304 is formed in a spiral shape centered on the rotation axis Or. Furthermore, by rotating around the rotation axis Or, the spiral portion 304 moves the powder stored in the lower space 108 from the lower space 108 to the upper space 106.

[0080] Also, the shape of the powder container 102 is made to conform to the rotation orbit of the stirring unit 30 so that the rotation of the stirring unit 30 and the stirring of the powder by the stirring unit 30 are facilitated. Here, the rotation orbit of the stirring unit 30 is circular. Therefore, here, as shown in FIGS. 7 and 8, the powder container 102 is formed in a frustum shape centered on the rotation axis Or.

[0081] As described above, the powder film forming apparatus 5 of the third embodiment is configured. Also in this third embodiment, the same effects as those of the first embodiment are achieved.

[0082] (Fourth Embodiment) In the fourth embodiment, the form of the stirring unit 30 is different from that of the third embodiment. Otherwise, it is the same as the third embodiment.

[0083] Specifically, as shown in FIG. 9, the stirring unit 30 has a plurality of protrusions 306 in addition to the shaft portion 300 and the spiral portion 304. The protrusions 306 protrude from the spiral portion 304.

[0084] As described above, the powder film forming apparatus 5 of the fourth embodiment is configured. Also in this fourth embodiment, the same effects as those of the third embodiment are achieved. Further, in the fourth embodiment, the following effects are also achieved.

[0085] When the stirring unit 30 rotates and the powder moves from the lower space 108 to the upper space 106, the protrusions 306 protruding from the spiral part 304 are interposed between the powders. Thereby, the aggregation of the powder is suppressed. For this reason, the generation of the portion where the raw material gas remains unadsorbed in the powder is suppressed. In addition, the generation of the portion that remains unreacted with the reaction gas among the powders adsorbed with the raw material gas is suppressed. Therefore, the generation of the portion that does not form a film in the powder is suppressed.

[0086] (Fifth Embodiment) In the fifth embodiment, the processing of the control unit 70 is different from that of the first embodiment. Other than this, it is the same as the first embodiment.

[0087] Here, in the first embodiment, the control unit 70 exhausts the gas in the internal space 104 during the period from time t4 to time t6, the period from time t9 to time t10, the period from time t14 to time t16, and the period from time t19 to time t20. Also, at these times, the rotation of the stirring unit 30 is stopped. Further, at these times, the supply of the purge gas is stopped.

[0088] On the other hand, in the fifth embodiment, as shown in the time chart of FIG. 10, the control unit 70 supplies the purge gas instead of stopping the supply of the purge gas during the period from time t4 to time t6. Also, the control unit 70 supplies the purge gas instead of stopping the supply of the purge gas during the period from time t9 to time t10. Further, the control unit 70 supplies the purge gas instead of stopping the supply of the purge gas during the period from time t14 to time t16. Also, the control unit 70 supplies the purge gas instead of stopping the supply of the purge gas during the period from time t19 to time t20.

[0089] As described above, the control unit 70 in the powder film forming apparatus 5 of the fifth embodiment performs processing. Also in this fifth embodiment, the same effects as those of the first embodiment are obtained. Further, in the fifth embodiment, the following effects are also obtained.

[0090] [3] When the control unit 70 exhausts the gas in the internal space 104, it stops the rotation of the stirring unit 30 and supplies purge gas to the upper space 106.

[0091] The purge gas supplied to the upper space 106 presses the powder stored in the lower space 108, making it difficult for the powder to scatter. Therefore, when exhausting the gas in the internal space 104, the discharge of the powder is suppressed. Also, when exhausting the raw material gas and the reaction gas, the purge gas supplied simultaneously with the exhaust makes it easier to dilute and displace the raw material gas and the reaction gas.

[0092] (Other embodiments) The present disclosure is not limited to the above embodiments, and appropriate changes can be made to the above embodiments. Also, in each of the above embodiments, it goes without saying that the elements constituting the embodiment are not necessarily essential, except in cases where it is explicitly stated that they are essential or where they are considered to be clearly essential in principle.

[0093] The control unit and its method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied by a computer program. Alternatively, the control unit and its method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Or, the control unit and its method described in the present disclosure may be realized by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured by one or more hardware logic circuits. Also, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer.

[0094] In each of the above embodiments, the powder film forming apparatus 5 forms a film of powder using ALD. In contrast, the powder film forming apparatus 5 is not limited to using ALD, and for example, may form a film of powder using MLD or the like. Further, the powder film forming apparatus 5 may form a film of powder using a film forming method in which a source gas and a reaction gas are alternately supplied. Note that MLD is an abbreviation for Molecular Layer Deposition, which is molecular layer deposition.

[0095] In the first, second, and fifth embodiments described above, the stirring unit 30 may have projections 306 in addition to the shaft portion 300 and the plate portion 302. In this case, the projections 306 project from the plate portion 302.

[0096] In the first to fourth embodiments described above, the exhaust valve 24 closes at time t5 and time t15. Further, the purge gas valve 64 opens at time t6 after time t5 and at time t16 after time t15. In contrast, the purge gas valve 64 may open simultaneously with the closing of the exhaust valve 24. Further, the purge gas valve 64 may open immediately before or immediately after the exhaust valve 24 closes.

[0097] In the fifth embodiment described above, the purge gas valve 64 is open during the period from time t5 to time t6 and during the period from time t15 to time t16. In contrast, the purge gas valve 64 may be closed during the period from time t5 to time t6 and during the period from time t15 to time t16.

[0098] The above embodiments may be combined as appropriate.

Description of Reference Numerals

[0099] 10 Chamber 20 Vacuum pump 30 Stirring unit 40 Source gas supply unit 50 Reaction gas supply unit 60 Purge gas supply unit 70 Control unit 104 Internal space 106 Upper space 108 Lower space

Claims

1. A powder film forming apparatus for forming a film from powder, comprising: a chamber (10) having an internal space (104) including an upper space (106) which is a space on the top side in the vertical direction and a lower space (108) which is a space on the bottom side in the vertical direction and stores the powder; an exhaust unit (20) for reducing the pressure of the internal space and exhausting the gas in the internal space; a stirring unit (30) that rotates about an axis (Or) to move the powder stored in the lower space from the lower space to the upper space; a raw material gas supply unit (40) for supplying a raw material gas to the upper space; a reaction gas supply unit (50) for supplying a reaction gas to the upper space; a control unit (70) for controlling the exhaust of the gas in the internal space by the exhaust unit, the rotation of the stirring unit, the supply of the raw material gas from the raw material gas supply unit, and the supply of the reaction gas from the reaction gas supply unit; and the control unit: when stopping the exhaust of the gas in the internal space, supplying the raw material gas to the upper space, and then stopping the supply of the raw material gas, adsorbs the raw material gas to the powder by rotating the stirring unit; when exhausting the gas in the internal space, stops the rotation of the stirring unit; when stopping the exhaust of the gas in the internal space, supplying the reaction gas to the upper space, and then stopping the supply of the reaction gas, rotates the stirring unit to react the raw material gas adsorbed to the powder with the reaction gas, thereby forming a film on the powder. A powder film forming apparatus.

2. The powder film forming apparatus further comprises a purge gas supply unit (60) for supplying a purge gas for expelling the raw material gas and the reaction gas from the internal space to the upper space, and the control unit controls the supply of the purge gas from the purge gas supply unit. The powder film forming apparatus according to claim 1.

3. The control unit: after supplying the raw material gas to the upper space, stops the supply of the raw material gas; after stopping the supply of the raw material gas, exhausts the gas in the internal space; after exhausting the gas in the internal space, stops the exhaust of the gas in the internal space; when stopping the exhaust of the gas in the internal space, supplies the purge gas to the upper space; when stopping the supply of the purge gas after supplying the purge gas to the upper space, rotates the stirring unit. The powder film forming apparatus according to claim 2.

4. The control unit after supplying the reaction gas to the upper space, stops the supply of the reaction gas, after stopping the supply of the reaction gas, exhausts the gas in the internal space, after exhausting the gas in the internal space, stops the exhaust of the gas in the internal space, when stopping the exhaust of the gas in the internal space, supplies the purge gas to the upper space, The powder film forming apparatus according to claim 2 or 3, wherein when stopping the supply of the purge gas after supplying the purge gas to the upper space, the stirring unit is rotated.

5. The powder film forming apparatus according to claim 2 or 3, wherein the control unit stops the rotation of the stirring unit and supplies the purge gas to the upper space when exhausting the gas in the internal space.

6. The chamber has a chamber bottom (102) that forms the lower space, The powder film forming apparatus according to claim 1 or 2, wherein the chamber bottom has a shape along the rotation orbit of the stirring unit.

7. The powder film forming apparatus according to claim 6, wherein the shaft extends in a direction perpendicular to the vertical direction.

8. The shaft extends in the vertical direction, The chamber has an upper surface (110) that forms the upper space, The chamber bottom is located on the ground side in the vertical direction and includes a bottom surface (112) that forms the lower space, The powder film forming apparatus according to claim 6, wherein the size of the bottom surface is smaller than the size of the upper surface.

9. The shaft extends in the vertical direction, The stirring unit includes the shaft and has a shaft portion (300) extending in the vertical direction, is connected to the shaft portion and is formed in a spiral shape centered on the shaft, and by rotating around the shaft, moves the powder stored in the lower space from the lower space to the upper space, a spiral portion (304), and a protrusion (306) protruding from the spiral portion, The powder film forming apparatus according to claim 1 or 2, having the above.

10. A powder film forming method for forming a powder film, comprising: a chamber (10) having an internal space (104) including an upper space (106) which is a space on the sky side in the vertical direction and a lower space (108) which is a space on the ground side in the vertical direction and in which the powder is stored, an exhaust unit (20) for reducing the pressure of the internal space and exhausting the gas in the internal space, A stirring unit (30) that rotates about an axis (Or) to move the powder stored in the lower space from the lower space to the upper space; A raw material gas supply unit (40) that supplies a raw material gas to the upper space; A reaction gas supply unit (50) that supplies a reaction gas to the upper space; are provided, When stopping the exhaust of the gas in the internal space, supplying the raw material gas to the upper space, and then stopping the supply of the raw material gas, the stirring unit is rotated to adsorb the raw material gas to the powder. When exhausting the gas in the internal space, the rotation of the stirring unit is stopped. A powder film forming method for forming a film on the powder by rotating the stirring unit when stopping the exhaust of the gas in the internal space, supplying the reaction gas to the upper space, and then stopping the supply of the reaction gas, thereby reacting the raw material gas adsorbed on the powder with the reaction gas.

Images