JP2008088451A - Film deposition method and film deposition system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film deposition system where, in film deposition by an aerosol deposition process, a film whose thickness and quality are uniform can be deposited. <P>SOLUTION: The film deposition system comprises: an aerosol production part where raw material powder is dispersed into a gas, so as to produce an aerosol; a film deposition chamber 6 where a substrate is arranged; an aerosol carrier tube 5 for carrying the aerosol produced in the aerosol production part to the film deposition chamber; a nozzle 7 arranged in the film deposition chamber and jetting the aerosol carried via the aerosol carrier tube toward the substrate; a substrate stage 8 for moving the position of the nozzle or the substrate for changing the relative position between the nozzle and the substrate; and a control part 10 for controlling each part for interrupting film deposition and cleaning the inside of the aerosol carrier tube. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a film forming method and a film forming apparatus for depositing a raw material on a substrate by spraying an aerosol in which the raw material powder is dispersed toward the substrate.

  In recent years, with the development of devices related to micro electrical mechanical systems (MEMS), elements such as multilayer ceramic capacitors and piezoelectric actuators have been increasingly miniaturized and integrated. Therefore, research for manufacturing such an element by using a film forming technique is actively pursued.

  Recently, an aerosol deposition (AD) method, which is one of film formation techniques using the collisional adhesion phenomenon of solid particles, has attracted attention as a method for forming a ceramic film. With the AD method, aerosol generated by dispersing fine powder of raw material in gas is sprayed from a nozzle toward a substrate, and the powder is made to collide with the substrate and the film formed earlier, In this film forming method, a raw material is deposited on a substrate. Here, the aerosol means “a colloidal system in which the dispersed phase is composed of solid or liquid particles and the dispersion medium is composed of gas” (Mikiji Takahashi, “Basics of Aerosol Science”, Morikita Publishing 1st Edition, P.1). According to the AD method, since the porosity is low and a dense and strong film can be formed, the performance of the fine element as described above may be improved.

  By the way, in order to form a high-quality film having a uniform thickness and density using such an AD method, it is important to spray an aerosol having a uniform concentration from a nozzle for a long time. This is because if the aerosol concentration is unstable, the film formation rate becomes non-uniform, resulting in variations in film thickness. In addition, during the generation of the aerosol, the raw material powders (primary particles) may aggregate to form a lump (secondary particles). Such a lump is only crushed and taken into the lower layer even if it collides with the substrate, and does not adhere to the lower layer. For this reason, when the aerosol contains a lot of secondary particles, the hardness and density of the film are lowered, and there is a problem that the quality of the film varies and defects occur. Therefore, a device for generating an aerosol having a uniform concentration and containing little secondary particles has been devised.

  As a related technology, Patent Document 1 discloses a film forming method in which an ultrafine particle is stirred with a gas to produce an aerosol, and the ultrafine particle in the aerosol is collided on the substrate to grow a film on the substrate. A method of forming ultrafine particles for producing an aerosol while applying ultrasonic waves to an aerosol forming chamber for producing an aerosol is disclosed.

  However, even if the concentration is uniform at the time of aerosol generation, the raw material powder may adhere to the inner wall of the pipe before the aerosol is conveyed to the nozzle, so the aerosol is sprayed from the nozzle. During this time, the concentration of the aerosol becomes thin. Moreover, the lump of the raw material powder once adhering to the inner wall of the pipe may be peeled off from the inner wall and mixed into the aerosol. In the portion where the lump of raw material powder is deposited, the film becomes thick, and the film thickness distribution varies. Therefore, it is necessary to devise so that the aerosol can smoothly pass through the pipe.

As such a contrivance, Patent Document 1 discloses that a straight tube-shaped hard material tube without an unevenness on the inner wall is used without a bent portion of metal or quartz whose inner wall is polished on the transport tube.
Further, in Patent Document 2, an aerosol in which fine particles of a brittle material are dispersed in a gas is sprayed from a nozzle toward a substrate, the aerosol collides with the substrate surface, and the fine particles are crushed and deformed by the impact of the collision. An apparatus for producing a composite structure is disclosed in which a structure made of the constituent material of the fine particles is formed on a substrate by bonding. In this composite structure manufacturing apparatus, a coating of a fluororesin or a conductive fluororesin is applied to the film formation chamber wall.

  Further, in Patent Document 3, an aerosol in which fine particles are dispersed in a gas is sprayed from the tip of a nozzle and sprayed onto a substrate to form a deposited layer made of a fine particle material on the substrate. In a composite structure manufacturing method for manufacturing a composite structure, the aerosol temperature is controlled to be higher than room temperature and 120 ° C. or lower.

Further, in Patent Document 4, in a composite structure manufacturing method in which an aerosol containing fine particles is sprayed onto a substrate at a high speed to directly form a composite structure, an aerosol transport pipe and a means for heating the nozzle are disposed, and the aerosol is provided. It is disclosed to suppress adhesion of fine particles and aggregated powder to the inner wall of the aerosol transport tube and the inner wall of the nozzle by heating the inner wall of the transport tube and the inner wall of the nozzle.
JP 2003-293159 A (2nd page) Japanese Patent Laying-Open No. 2005-89826 (first page) Japanese Patent Laying-Open No. 2003-213450 (second page) Japanese Patent Laying-Open No. 2003-2111030 (first page)

  However, by coating the inner wall of the aerosol pipe or heating the pipe, the raw material powder can be prevented from adhering to the inner wall in the short term, but the raw material powder will also adhere in the long term. And once the raw material powder adheres to the inner wall, the raw material powder becomes more and more likely to adhere to that part, so the aerosol concentration is significantly reduced, and as a result, it becomes difficult to form a film with a uniform thickness . Furthermore, the lump of the raw material powder that has been peeled off from such a portion is mixed into the aerosol, so that the thickness and quality (hardness, density, etc.) of the film become non-uniform.

  In view of the above, an object of the present invention is to provide a film forming method and a film forming apparatus capable of forming a film having a uniform thickness and quality in film formation by an aerosol deposition method.

  In order to solve the above problems, a film forming method according to one aspect of the present invention is a method of forming a film having a composition of raw material powder by spraying the raw material powder onto a substrate, and dispersing the raw material powder in a gas. A step (a) for generating an aerosol, a step (b) for transporting the aerosol generated in the step (a) to a nozzle disposed in the film forming chamber via a transport path, The step (c) of depositing raw material powder on the substrate by injecting aerosol from the nozzle toward the substrate, and the step (d) of interrupting the step (c) and cleaning the inside of the conveyance path It has.

  In addition, a film forming apparatus according to one aspect of the present invention is an aerosol formed by dispersing a raw material powder in a gas in a film forming apparatus that forms a film having a composition of the raw material powder by spraying the raw material powder onto a substrate. An aerosol generating means for generating a film, a film forming chamber in which a substrate is disposed, a transport path for transporting the aerosol generated by the aerosol generating means to the film forming chamber, and a transport path disposed in the film forming chamber and transported through the transport path A nozzle for injecting the applied aerosol toward the substrate, a moving means for moving the position of the nozzle or the substrate in order to change the relative position between the nozzle and the substrate, and transport when the film formation is interrupted Cleaning means for cleaning the inside of the path.

  According to the present invention, since the piping for transporting the generated aerosol to the nozzle is cleaned at a predetermined frequency, adhesion of the raw material powder to the inner wall of the piping can be suppressed. Thereby, it becomes possible to spray an aerosol having a constant concentration from the nozzle, and it is possible to prevent the lump of the raw material powder from being mixed into the aerosol. Therefore, a film having a uniform thickness and quality can be formed over a long period of time.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, the same reference number is attached | subjected to the same component and description is abbreviate | omitted.
FIG. 1 is a schematic diagram showing a configuration of a film forming apparatus according to the first embodiment of the present invention. As shown in FIG. 1, this film forming apparatus includes an aerosol generating unit 1 to 4 where aerosol generation is performed, a film forming unit 6 to 9, an aerosol transport pipe 5 connecting the two, and the operation of each unit. The control part 10 which controls is included.

The aerosol generation unit includes an aerosol generation chamber 1, a vibration table 2, a hoisting gas nozzle 3, and a pressure adjusting gas nozzle 4.
The aerosol generation chamber 1 is a container in which raw material powder (raw material powder) 11 is disposed, and aerosol is generated here. The aerosol generation chamber 1 is installed on a vibration table 2 that vibrates at a predetermined frequency in order to efficiently generate aerosol by stirring the raw material powder 11.

The winding gas nozzle 3 generates a cyclone flow by introducing a carrier gas supplied from an external gas cylinder into the aerosol generation chamber 1. Thereby, the raw material powder 11 arrange | positioned in the aerosol production | generation chamber 1 is wound up and disperse | distributed, and an aerosol is produced | generated.
The pressure adjusting gas nozzle 4 adjusts the gas pressure in the aerosol generating chamber 1 by introducing a carrier gas supplied from an external gas cylinder into the aerosol generating chamber 1. Thereby, the difference between the pressure in the aerosol generation chamber 1 and the pressure in the film formation chamber 6 is adjusted.

The flow rate of the gas introduced by the hoisting gas nozzle 3 and the pressure adjusting gas nozzle 4 is adjusted by the flow rate adjusting units 3a and 4a. Further, as the carrier gas supplied by the hoisting gas nozzle 3 and the pressure adjusting gas nozzle 4, helium (He), oxygen (O ₂ ), nitrogen (N ₂ ), argon (Ar), or a mixed gas thereof, or Dry air or the like is used.

  The aerosol transport pipe 5 is a path for transporting the aerosol from the aerosol generating unit toward the film forming unit. In the film forming chamber 6, the aerosol transport pipe 5 is connected to a nozzle 7 for injecting aerosol. Here, the material for forming the aerosol transport pipe 5 is not particularly limited, but a transparent material (a material having optical transparency) may be used so that the inside of the aerosol transport pipe 5 can be observed from the outside. . Specific examples include transparent resin materials such as PMMA (acrylic), PBT (polybutylene terephthalate), PP (polypropylene), and PC (polycarbonate). Alternatively, a glass material such as quartz or Pyrex (registered trademark) may be used. Moreover, it is preferable to use transparent PFA Teflon (registered trademark) from the viewpoint that adhesion of the raw material powder in the aerosol transport pipe 5 can be suppressed. Here, PFA is a fluororesin composed of a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether.

The film forming unit includes a film forming chamber 6, an injection nozzle 7, a substrate stage 8, and an exhaust pipe 9.
The injection nozzle 7 has an opening having a predetermined shape and size, and injects the aerosol of the raw material powder supplied from the aerosol generation chamber 1 via the aerosol transport pipe 5 toward the substrate 12. The velocity of the aerosol ejected from the ejection nozzle 7 is determined by the pressure difference between the aerosol generation chamber 1 and the film formation chamber 6.

The substrate stage 8 on which the substrate 12 is fixed is a three-dimensionally movable stage for controlling the relative position and relative speed between the substrate 12 and the injection nozzle 7. By adjusting this relative speed, the thickness of the film formed per reciprocation is controlled.
In this embodiment, the relative position between the nozzle 7 and the substrate stage 8 is changed by moving the substrate stage 8 side. However, the position of the substrate is fixed and the nozzle 7 side is moved. Anyway.
The inside of the film forming chamber 6 is evacuated by an evacuation pump connected to an evacuation pipe 9, thereby maintaining a predetermined degree of vacuum.

Next, the operation of the film forming apparatus according to this embodiment will be described.
In the AD method, for example, ceramic powder such as PZT (lead zirconate titanate) or Al ₂ O ₃ (alumina) is used as the raw material powder. As shown in FIG. 1, such raw material powder 11 is disposed in the aerosol generation chamber 1 and the substrate 12 is disposed on the substrate stage 8. When the film forming apparatus is driven, the aerosol generated in the aerosol generating chamber 1 is introduced into the film forming chamber 6 through the aerosol transport pipe 5, sprayed from the nozzle 7, and sprayed onto the substrate 12. The raw material powder in the aerosol adheres to and accumulates on the substrate 12. At that time, by moving the substrate stage 8 at a predetermined speed under the control of the control unit 10, at a rate according to the moving speed of the substrate stage 8 (relative speed between the nozzle 7 and the substrate stage 8), A film 13 having the same composition as the raw material powder is formed.

  Moreover, the control part 10 controls each part so that the aerosol conveyance pipe | tube 5 may be cleaned with predetermined frequency between film-forming processes. This frequency may be set based on the film formation distance (relative scanning distance of the nozzle 7 with respect to the substrate 12), or may be set based on the film formation time (aerosol injection time).

  In the cleaning process of the aerosol transport pipe 5, first, the substrate 12 is shifted from the spraying direction of the nozzle 7 so that the substance sprayed from the nozzle 7 is not sprayed onto the substrate 12 by operating the substrate stage 8. In this state, a cleaning medium is introduced into the aerosol transport pipe 5 and ejected from the nozzle 7.

  In this embodiment, a purge gas is used as the cleaning medium. That is, by stopping the introduction of the carrier gas from the hoisting gas nozzle 3 in the aerosol generating unit, the carrier gas not containing the raw material powder 11 is introduced into the aerosol transport pipe 5 as the purge gas. At that time, in order to efficiently clean the inside of the aerosol transport pipe 5, it is desirable to make the flow rate of the carrier gas faster than the flow rate at the time of normal aerosol transport. The flow rate of the carrier gas may be increased. The operations of the flow rate adjusting units 3a and 4a in the cleaning process may be automatically controlled by the control unit 10 according to the frequency of the cleaning process, or may be manually operated by the user.

  According to this embodiment, since the raw material powder adhering to the inner wall of the aerosol transport pipe is periodically removed by performing the cleaning process at a predetermined frequency between the film forming processes, the raw material powder peeled off from the inner wall It is possible to prevent the lump from being mixed into the aerosol. Moreover, since the raw material powder can be prevented from adhering to the inner wall by keeping the inner wall smooth, it is possible to keep the concentration of aerosol sprayed from the nozzle constant. Furthermore, according to the present embodiment, the cleaning process is performed by controlling the gas supply in the aerosol generating unit and the operation of the substrate stage in the film forming unit in the AD film forming apparatus having a general configuration. Therefore, a film having a uniform film thickness and quality can be easily obtained at low cost.

  Further, when the aerosol transport pipe 5 is formed of a transparent material, by visually observing the inside from the outside, when the aerosol transport pipe 5 is contaminated with the raw material powder, the film formation is stopped or the cleaning process is performed. This makes it easier to plan the timing of the implementation. It is also possible to restart the film formation after confirming that the inside of the aerosol carrying tube 5 has been sufficiently cleaned. In this case, the cleaning process may be performed manually by visually observing the inside of the transparent aerosol transport pipe 5 without using the control unit.

Next, a film forming apparatus according to a second embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 2, the film forming apparatus according to this embodiment is different from the film forming apparatus shown in FIG. 1 in the cleaning medium supply unit 21 connected to the aerosol transport pipe 5 and the aerosol transport pipe 5. And a valve 22 provided. Other configurations are the same as those shown in FIG.

  In the present embodiment, the cleaning process performed at a predetermined frequency between the film forming processes is performed by transporting the cleaning medium from the cleaning medium supply unit 21 in the state where the valve 22 is closed and the supply of the aerosol is stopped. This is done by introducing it into the tube 5. At this time, the substrate 12 is arranged so as to be shifted from the spraying direction of the nozzle 7 so that the cleaning medium sprayed from the nozzle 7 is not sprayed onto the substrate 12. The operations of the cleaning medium supply unit 21, the valve 22, and the substrate stage 8 may be automatically controlled by the control unit 10 according to the frequency of the cleaning process, or may be manually operated by the user. May be.

  As the cleaning medium, a substance having a relatively high volatility such as an organic solvent such as alcohol or acetone is used. This is because such a substance volatilizes immediately even if it is injected from the nozzle 7 into the film chamber 6 through the aerosol carrying tube 5 and has a small influence on the film forming process that is resumed thereafter.

Next, a film forming apparatus according to a third embodiment of the present invention will be described.
Also in this embodiment, the cleaning process performed at a predetermined frequency between the film forming processes is performed for cleaning from the cleaning medium supply unit 21 shown in FIG. 2 to the aerosol transport pipe 5 as in the second embodiment. This is done by introducing a medium. At this time, in this embodiment, an aerosol in which a powder having a diameter larger than that of the raw material powder 11 is dispersed in the gas is used as the cleaning medium.

  Here, since the powder having a diameter larger than that of the raw material powder has a large mass, when the powder is passed through the aerosol transport pipe 5 in an aerosol state, the powder having a larger kinetic energy collides with the inner wall. As a result, the powder acts like an abrasive and peels off the raw material powder adhering to the inner wall of the aerosol transport tube 5. Thereby, the inside of the aerosol carrying tube 5 is cleaned. On the other hand, the raw material powder peeled off from the inner wall is discharged from the nozzle 7 together with the aerosol as a cleaning medium.

  Moreover, it is desirable that the aerosol used as the cleaning medium is generated using a powder having the same composition as the raw material powder. This powder is to remain in the film forming chamber 6 even after being discharged into the film forming chamber 6 in the cleaning process, so that the presence of foreign matter in the film forming chamber 6 is minimized.

Next, a film forming apparatus according to a fourth embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 3, the film forming apparatus according to the present embodiment further includes a discharge pipe 31 connected to the aerosol transport pipe 5 via a three-way valve 32. Other configurations are the same as those shown in FIG.

In the film forming process, the three-way valve 32 is set in such a direction that the aerosol transport pipe 5 communicates with the nozzle 7. On the other hand, in the cleaning process performed at a predetermined frequency between the film forming processes, the three-way valve 32 is switched in a direction in which the aerosol transport pipe 5 communicates with the discharge pipe 31. Thereby, the cleaning medium introduced into the aerosol transport pipe 5 is guided in the direction of the discharge pipe 31.
The operation of the three-way valve 32 may be automatically controlled by the control unit 10 according to the frequency of the cleaning process, or may be manually operated by the user.

  As the cleaning medium, the carrier gas supplied from the aerosol generating unit may be used as the purge gas, as in the first embodiment. Alternatively, as in the second embodiment, by separately providing a cleaning medium supply unit, it is possible to clean an aerosol in which a volatile organic solvent or a powder having a particle size larger than that of the raw material powder is dispersed in the gas. It may be used as a medium for use.

  According to this embodiment, it is not necessary to shift the relative positions of the nozzle 7 and the substrate 12 in order to prevent the cleaning medium sprayed from the nozzle 7 from being sprayed onto the substrate 12 during the cleaning process. Therefore, after the cleaning process is completed, the film forming process can be restarted from the immediately preceding film forming position. Accordingly, it is possible to reduce time loss due to switching between the film forming process and the cleaning process, and to prevent a shift in the film forming position.

  As a modification of the film forming apparatus according to this embodiment, an exhaust pump may be separately provided at the end of the discharge pipe 31. That is, in the cleaning process, the carrier gas (purge gas) is passed through the aerosol transport pipe 5 by the exhaust pump, and the exhaust is led out from the exhaust pipe 31 to the exhaust pump.

Next, a film forming apparatus according to a fifth embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 4, the film forming apparatus according to the present embodiment further includes a shielding plate 41 with respect to the film forming apparatus shown in FIG. The shielding plate 41 is held in a movable state by a shielding plate holding unit (not shown) that operates under the control unit 10. Other configurations are the same as those shown in FIG.

  FIG. 4 shows a state of the cleaning process performed at a predetermined frequency between the film forming processes. In the cleaning process, first, the shielding plate 41 is inserted between the nozzle 7 and the substrate 12 so that the cleaning medium sprayed from the nozzle 7 is not sprayed onto the substrate 12. In this state, the cleaning medium is introduced into the aerosol transport pipe 5 and led out from the nozzle 7. On the other hand, in the film forming process, the shielding plate 41 is moved from the spraying direction of the nozzle 7 so that the aerosol sprayed from the nozzle 7 is sprayed onto the substrate 12. In order to operate the shielding plate 41 in this way, the control unit 10 may automatically control the shielding plate holding unit according to the frequency of the cleaning process, or the user manually operates the shielding plate holding unit. You may operate.

  As the cleaning medium, the carrier gas supplied from the aerosol generating unit may be used as the purge gas, as in the first embodiment. Alternatively, as in the second embodiment, by separately providing a cleaning medium supply unit, it is possible to clean an aerosol in which a volatile organic solvent or a powder having a particle size larger than that of the raw material powder is dispersed in the gas. It may be used as a medium for use.

  According to this embodiment, it is not necessary to shift the relative positions of the nozzle 7 and the substrate 12 in order to prevent the cleaning medium sprayed from the nozzle 7 from being sprayed onto the substrate 12 during the cleaning process. Therefore, after the cleaning process is completed, the film forming process can be restarted from the immediately preceding film forming position. Accordingly, it is possible to reduce time loss due to switching between the film forming process and the cleaning process, and to prevent a shift in the film forming position.

Next, a film forming apparatus according to a sixth embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 5, the film forming apparatus according to this embodiment is different from the film forming apparatus shown in FIG. 1 in that the valve 51 provided in the aerosol transport pipe 5 and the upstream side of the valve 51 (the aerosol generating unit side). ) Is further provided with a vacuum gauge (for example, a Pirani gauge) 52. Other configurations are the same as those shown in FIG.

  In the present embodiment, in the cleaning process performed at a predetermined frequency between the film forming processes, the carrier gas supplied from the aerosol generating unit is used as a cleaning medium (purge gas) in the same manner as in the first embodiment. In this case, the carrier gas is intermittently introduced into the aerosol transport pipe 5. That is, once the valve 51 is closed, the pressure on the upstream side of the valve 51 is increased. Then, by observing the vacuum gauge 52, the valve 51 is opened when the upstream side of the valve 51 becomes sufficiently high in pressure. As a result, the carrier gas is ejected from the aerosol generating section that has become high pressure, and passes through the aerosol transport pipe 5 at a stretch. By repeating such an operation several times, the inside of the aerosol transport pipe 5 is cleaned.

Alternatively, by adjusting the opening / closing state of the valve 51 or adjusting the flow rate of the carrier gas introduced from the pressure adjusting gas nozzle 4, the pressure of the carrier gas introduced into the aerosol transport pipe 5 as a cleaning medium is changed. Also good.
Such an operation of the valve 51 may be automatically controlled by the control unit 10 according to the frequency of the cleaning process, or may be manually operated by the user.

  Here, in FIG. 5, in order to prevent the gas jetted from the nozzle 7 from being sprayed onto the substrate 12 in the cleaning process, the substrate 12 is arranged shifted from the jetting direction of the nozzle 7. However, for the same purpose, by providing a three-way valve as shown in FIG. 3, gas is led out in a direction other than the nozzle 7, or between the nozzle 7 and the substrate 12 as shown in FIG. A shielding plate 41 may be provided.

Next, a film forming apparatus according to a seventh embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 6, the film forming apparatus according to this embodiment is different from the film forming apparatus shown in FIG. 1 in that a valve 61 provided in the aerosol transport pipe 5 and a valve 62 provided in the exhaust pipe 9 are provided. And a gas supply pipe 63 provided in the film forming chamber 6. Other configurations are the same as those shown in FIG.

In the present embodiment, in the cleaning process performed at a predetermined frequency between the film forming processes, the inside of the aerosol transport pipe 5 is sucked using the pressure change in the film forming chamber 6, and the sucked residue Is derived from the nozzle 7. That is, first, the supply of aerosol is stopped by closing the valve 61. On the other hand, while introducing gas from the gas supply pipe 63 into the film forming chamber 6 and adjusting the valve 62 to suppress exhaust of the film forming chamber 6, the degree of vacuum in the film forming chamber 6 is lowered. Alternatively, the exhaust in the film forming chamber 6 may be stopped by completely closing the valve 62. In any case, it is desirable to set the inside of the film forming chamber 6 at this time to about atmospheric pressure. Thereafter, the gas supply from the gas supply pipe 63 is stopped, and the valve 62 is opened at once. As a result, the inside of the film forming chamber 6 and the aerosol transport pipe 5 is rapidly exhausted, and accordingly, the residue in the aerosol transport pipe 5 is sucked and ejected from the nozzle 7. By repeating such an operation several times, the inside of the aerosol transport pipe 5 is cleaned.
The operations of the valves 61 and 62 and the gas supply pipe 63 may be automatically controlled by the control unit 19 according to the frequency of the cleaning process, or may be manually operated by the user. .

  Here, in FIG. 6, in order to prevent the gas jetted from the nozzle 7 from being sprayed onto the substrate 12 in the cleaning process, the substrate 12 is arranged shifted from the jetting direction of the nozzle 7. However, for the same purpose, by providing a three-way valve as shown in FIG. 3, gas is led out in a direction other than the nozzle 7, or between the nozzle 7 and the substrate 12 as shown in FIG. A shielding plate 41 may be provided.

  Further, as a modification of the present embodiment, a leak valve is provided instead of the gas supply pipe 63, and in the cleaning process, the leak valve is opened to introduce outside air into the film forming chamber 6, so that the inside of the film forming chamber 6 is The degree of vacuum may be reduced.

In the first to seventh embodiments described above, the aerosol is generated by introducing the carrier gas into the container in which the raw material powder is arranged. However, the aerosol can be generated by various other methods, and any method can be applied to the film forming apparatus according to the above-described embodiment.
For example, instead of the aerosol generation unit illustrated in FIGS. 1 to 6, the aerosol generation device illustrated in FIG. 7 may be used. FIG. 7A is a cross-sectional view showing the configuration of the aerosol generating device, and FIG. 7B is a plan view showing the inside of the aerosol generating device.

The aerosol generation device shown in FIG. 7 includes a powder storage chamber 70 and an aerosol generation unit 80.
The powder storage chamber 70 is a chamber for storing powder, and a powder supply port 70a is provided at the upper bottom thereof, and an opening 71 is formed at the lower bottom thereof. The powder storage chamber 70 and the aerosol generation unit 80 are connected via the opening 71.

The powder storage chamber 70 is provided with a stirring blade 72 that rotates when driven by a motor. An O (O) ring 73a is fitted on the rotating shaft 73 of the stirring blade 72, thereby ensuring airtightness in the powder storage chamber 70. In FIG. 7B, four stirring blades 72 are shown, but the number of stirring blades may be changed as appropriate. As the material of the stirring blade 72, a hard material such as metal may be used, or a material having excellent flexibility such as rubber, silicon rubber, Teflon (registered trademark), or the like may be used. Or you may use combining those materials, such as covering the peripheral part of a metal feather with rubber | gum.
The powder is stored in such a powder storage chamber 70, and the powder is stirred by the stirring blade 72. Thereby, the powder falls from the opening 71 and is led out to the aerosol generating unit 80.

  Further, an assist gas introduction portion 74 is provided in the powder storage chamber 70 in order to assist or promote the powder being led out from the opening 71. The assist gas introduction unit 74 includes a pipe and a valve. For example, a gas cylinder is connected to the end of the pipe. In addition, as a kind of assist gas, it is desirable to use the same thing as the dispersion gas mentioned later.

The aerosol generating unit 80 includes a rotating disk 81 that rotates when driven by a motor. An O-ring 82 is fitted into the rotation shaft 82 of the turntable 81, thereby ensuring airtightness in the aerosol generating unit 80.
A groove 83 having a predetermined width and depth is formed in the turntable 81 along the circumference. The turntable 81 is arranged so that the groove 83 faces the opening 71 of the powder storage chamber 70. Such a rotating plate 81 conveys the powder at a certain ratio by rotating while receiving the powder dropped from the opening 71 through the groove 83. In FIG. 7A, the cross-sectional shape of the groove 83 is a semicircle, but it may be a shape other than a semicircle, such as a rectangle or a V shape.

Further, the aerosol generating unit 80 is provided with a dispersed gas introducing unit 84 and an aerosol deriving unit 85.
The dispersed gas introduction unit 84 includes a pipe and a valve, and a gas cylinder is connected to the end of the pipe, for example. As the kind of the dispersion gas, nitrogen (N ₂ ), oxygen (O ₂ ), helium (He), argon (Ar), a mixed gas thereof, dry air, or the like is used. As shown in FIG. 7A, the outlet of the dispersed gas introduced into the aerosol generating unit 80 by the dispersed gas introducing unit 84 is provided so as to face the groove 83 of the rotating plate 81.
The aerosol lead-out portion 85 is a tube arranged so that the opening at the tip faces the groove 83, and the other end is, for example, an aerosol carrying tube shown in FIG. 1 via a pipe formed of a flexible material. 5 is connected.

In such an aerosol generating apparatus, desired powder is stored in the powder storage chamber 70 and the stirring blade 72 is driven, and the rotating plate 81 is rotated in the aerosol generating unit 80 so that the groove 83 of the rotating plate 81 is rotated. And spray the dispersion gas.
The powder stored in the powder storage chamber 70 falls into the groove 83 through the opening 71 while being stirred by the stirring blade 72. At that time, an air flow is formed in the opening 71 by introducing an assist gas into the powder storage chamber 70. This airflow acts as a driving force that assists or accelerates the derivation of the powder. Thereby, the powder falls from the opening 71 into the groove 83 more smoothly. The powder that has fallen into the groove 83 is deposited and conveyed in accordance with the rotational speed of the turntable 82. The assist gas may be introduced continuously or intermittently.

  On the other hand, in the groove 83 of the turntable 82, the dispersed gas blown there flows along the groove 83 to form an air flow. This dispersed gas flows into the inside of the aerosol lead-out portion 85 through the opening at the tip. At that time, a suction force toward the inside of the aerosol deriving unit 85 is generated around the aerosol deriving unit 85. Due to this suction force, the powder accumulated in the groove 83 flows into the aerosol outlet 85 together with the dispersed gas. The aerosol generated in this way is introduced into the film forming section through the aerosol outlet 85 and the aerosol transport pipe 5 (FIG. 1).

  According to the aerosol generating apparatus shown in FIG. 7, since a certain amount of powder can be conveyed to the end of the aerosol deriving unit 85, the concentration of the aerosol can be kept constant. In addition, the aerosol concentration can be adjusted to a desired concentration by adjusting the rotation speed of the turntable 81.

  Various known techniques may be combined with the first to seventh embodiments described above. For example, as shown in FIG. 8, a heating mechanism 91 is provided in the aerosol carrier tube 5 to heat the aerosol carrier tube 5, or as shown in FIG. 9, the aerosol carrier tube 5 has a vibration mechanism such as an ultrasonic generator. 92 may be provided to vibrate the aerosol carrying tube 5. Or you may provide both a heating mechanism and a vibration mechanism in one aerosol conveyance pipe. This makes it difficult for the raw material powder to adhere to the inner wall, and easily peels off even if the raw material powder once adheres to the inner wall, thereby improving the efficiency of the cleaning process.

Experiments for producing PZT (lead zirconate titanate) films were performed using the film forming apparatuses according to the first to seventh embodiments of the present invention. Common film formation conditions used in the experiment are as follows.
Raw material powder: PNN-PZT powder manufactured by Furuuchi Chemical Co., Ltd. Carrier gas: oxygen (O ₂ ) 6 liters / minute

(Example 1)
The film forming apparatus shown in FIG. 5 was used as the film forming apparatus, and the aerosol generating apparatus shown in FIG. 7 was connected instead of the aerosol generating unit shown in FIG. In this experiment, a transparent PFA Teflon (registered trademark) tube was used as the aerosol carrying tube 5 so that the inside of the aerosol carrying tube 5 was visible from the outside. In addition, one PZT film was produced by spraying aerosol 10 times on the substrate 12, and during that time, one cleaning process was performed for each reciprocation. In one cleaning process, the operation of closing the valve 51 once and opening the valve 51 when the vacuum gauge (Pirani gauge) 52 reached about 0.5 MPa was repeated 10 times. In addition, after the cleaning process, it was visually confirmed that the raw material powder did not adhere to the inside of the aerosol transport pipe 5.

(Example 2)
The film forming apparatus shown in FIG. 6 was used as the film forming apparatus, and the aerosol generating apparatus shown in FIG. 7 was connected instead of the aerosol generating unit shown in FIG. In this experiment, transparent PFA Teflon (registered trademark) was used as a material for the aerosol carrying tube 5 so that the inside of the aerosol carrying tube 5 was visible from the outside. In addition, one PZT film was produced by spraying aerosol 10 times on the substrate 12, and during that time, one cleaning process was performed for each reciprocation. In one cleaning process, the following operation was repeated three times. That is, after the valve 61 was closed and the supply of aerosol was stopped, the valve 62 was closed to stop the exhaust, and the gas was introduced through the gas supply pipe 63, whereby the inside of the film forming chamber 6 was brought to atmospheric pressure. Thereafter, the valve 62 was opened at a stroke to suck the inside of the aerosol transport pipe 5. In addition, after such a cleaning process, it confirmed visually that the raw material powder did not adhere to the inside of the aerosol conveyance pipe 5.

(Comparative example)
One PZT film was produced by spraying aerosol 10 times on the substrate 12. Note that no cleaning process was performed between the film forming processes.

The film thicknesses of the PZT films (20 sheets each) prepared in Examples 1 and 2 and the comparative example were measured using a stylus type surface shape measuring instrument Dektak 6M manufactured by ULVAC, Inc. And the average film thickness of 5 sheets extracted from 20 sheets, the maximum film thickness in 20 sheets, and the minimum film thickness were calculated | required, and the average and the fluctuation range were calculated using the following formula based on these values. .
Average = (maximum film thickness + minimum film thickness) / 2
Fluctuation width = (maximum film thickness−average) / average film thickness × 100 (%)

FIG. 10 shows the experimental results.
As shown in FIG. 10, in the comparative example, the thickness of one PZT film increases as the film formation is repeated. This is presumably because the raw material powder adhered to the aerosol transport tube, and the lump of raw material powder peeled off from the aerosol transport tube was mixed in the PZT film. Therefore, the fluctuation range of the film thickness is large (43%), and it is difficult to obtain a uniform film thickness.

  On the other hand, in Examples 1 and 2, even when the film formation was repeated, no increase tendency of the film thickness was observed, and the fluctuation range was within a small range (24% and 17%). Therefore, it was confirmed that a film having a relatively uniform thickness can be obtained by performing the cleaning process between the film forming processes.

  The present invention can be used in a film forming method and a film forming apparatus for depositing a raw material on a substrate by spraying an aerosol in which the raw material powder is dispersed toward the substrate.

It is a schematic diagram which shows the structure of the film-forming apparatus which concerns on the 1st Embodiment of this invention. It is a schematic diagram which shows the structure of the film-forming apparatus which concerns on the 2nd Embodiment of this invention. It is a schematic diagram which shows the structure of the film-forming apparatus which concerns on the 4th Embodiment of this invention. It is a schematic diagram which shows the structure of the film-forming apparatus which concerns on the 5th Embodiment of this invention. It is a schematic diagram which shows the structure of the film-forming apparatus which concerns on the 6th Embodiment of this invention. It is a schematic diagram which shows the structure of the film-forming apparatus which concerns on the 7th Embodiment of this invention. It is a figure which shows the structure of the aerosol production | generation apparatus which can be utilized in the film-forming apparatus which concerns on the 1st-7th embodiment of this invention. It is a schematic diagram which shows the structure of the film-forming apparatus provided with the heating mechanism in the aerosol conveyance pipe. It is a schematic diagram which shows the structure of the film-forming apparatus provided with the vibration mechanism in the aerosol conveyance pipe. It is a figure which shows the result of Example 1 and 2 in the experiment which forms a PZT film | membrane, and a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aerosol production | generation chamber 2 Shaking table 3 Hoisting gas nozzle 3a, 4a Pressure adjustment part 4 Pressure adjustment nozzle 5 Aerosol conveyance pipe 6 Film formation chamber 7 Nozzle 8 Substrate stage 9 Exhaust pipe 10 Control part 11 Raw material powder 12 Substrate 13 Film 21 Cleaning medium Supply portion 22, 51, 61, 62 Valve 31 Discharge pipe 32 Three-way valve 41 Shield plate 52 Vacuum gauge 63 Gas supply pipe 70 Powder storage chamber 70a Powder supply port 71 Opening 72 Stirring blade 72a Lowermost portions 73, 82 of the stirring blade Rotating shafts 73a, 82a O (O) ring 74 Assist gas introduction unit 80 Aerosol production chamber 81 Rotating disc 83 Groove 84 Dispersed gas introduction unit 85 Aerosol derivation unit 91 Heating mechanism 92 Vibration mechanism

Claims (41)

In the method of forming a film having the composition of the raw material powder by spraying the raw material powder on the substrate,
A step (a) of generating an aerosol by dispersing raw material powder in a gas;
A step (b) of transporting the aerosol generated in the step (a) to a nozzle disposed in the film forming chamber via a transport path;
In the film formation chamber, by spraying aerosol from the nozzle toward the substrate,
A step (c) of depositing raw material powder on a substrate;
A step (d) of interrupting the step (c) and cleaning the inside of the conveyance path;
A film forming method comprising:   The film forming method according to claim 1, wherein the step (d) includes shifting the substrate from an ejection direction of the nozzle, introducing a cleaning medium into the transport path, and leading out from the nozzle.   The film forming method according to claim 1, wherein the step (d) includes introducing a cleaning medium into the conveyance path and deriving the cleaning medium in a direction different from the nozzle.   The film forming method according to claim 1, wherein the step (d) includes disposing a shielding plate between the nozzle and the substrate, and introducing a cleaning medium into the conveyance path and leading out from the nozzle. .   The film forming method according to claim 2, wherein the cleaning medium is a purge gas.   The film forming method according to claim 5, wherein step (d) includes introducing a cleaning medium into the conveyance path intermittently or while changing pressure.   The film forming method according to claim 2, wherein the cleaning medium is a volatile organic solvent.   The film forming method according to claim 2, wherein the cleaning medium is an aerosol in which particles having a diameter larger than that of the raw material powder are dispersed in a gas.   The film forming method according to claim 1, wherein the step (d) includes cleaning the inside while heating the conveyance path.   The film forming method according to claim 1, wherein the step (d) includes cleaning the inside while vibrating the transport path.   11. The method according to claim 1, wherein the step (d) includes cleaning the inside of the conveyance path while the conveyance of the aerosol generated in the step (a) to the nozzle is stopped. The film forming method.   The film forming method according to claim 1, wherein the step (d) includes sucking a residue in the transport path in a state where the transport of the aerosol generated in the step (a) to the nozzle is stopped.   The step (d) includes suctioning the residue in the transport path into the film forming chamber by evacuating the film forming chamber after the pressure in the film forming chamber is once increased. Item 13. A film forming method according to Item 12.   The film forming method according to claim 13, wherein step (d) includes increasing the pressure in the film forming chamber to atmospheric pressure.   The film formation according to any one of claims 12 to 14, wherein the step (d) includes shifting the substrate from an ejection direction of the nozzle and sucking a residue in the transport path into the film formation chamber. Method.   The film forming method according to claim 12, wherein the step (d) includes sucking the residue in the transport path in a direction different from that of the nozzle.   The step (d) includes disposing a shielding plate between the nozzle and the substrate, and sucking a residue in the transport path from the nozzle. Film forming method.   The film forming method according to claim 1, wherein the step (d) includes cleaning while observing the inside of the conveyance path from the outside. Step (a) is
A step (a1) of transferring the powder stored in the powder storage chamber in which the opening is formed in a groove having a predetermined width and depth;
Dispersing the powder derived from the opening with a gas (a2);
The film-forming method of any one of Claims 1-18 containing this.   20. The aerosol generating method according to claim 19, wherein step (a2) includes generating an aerosol by blowing a gas on the powder conveyed in step (a1). In the film forming apparatus for forming a film having the composition of the raw material powder by spraying the raw material powder on the substrate,
Aerosol generating means for generating an aerosol by dispersing raw material powder in a gas;
A film forming chamber in which a substrate is disposed;
A transport path for transporting the aerosol generated by the aerosol generating means to the film forming chamber, the transport path formed of a material having optical transparency;
A nozzle that is disposed in the film forming chamber and injects the aerosol transported through the transport path toward the substrate;
Moving means for moving the position of the nozzle or the substrate to change the relative position between the nozzle and the substrate;
A film forming apparatus comprising: In the film forming apparatus for forming a film having the composition of the raw material powder by spraying the raw material powder on the substrate,
Aerosol generating means for generating an aerosol by dispersing raw material powder in a gas;
A film forming chamber in which a substrate is disposed;
A transport path for transporting the aerosol generated by the aerosol generating means to the film forming chamber;
A nozzle that is disposed in the film forming chamber and injects the aerosol transported through the transport path toward the substrate;
Moving means for moving the position of the nozzle or the substrate to change the relative position between the nozzle and the substrate;
A cleaning means for cleaning the inside of the conveyance path when film formation is interrupted;
A film forming apparatus comprising:   The film forming apparatus according to claim 22, wherein the transport path is formed of a light transmissive material.   The cleaning unit is configured to introduce a cleaning medium supply unit that introduces a cleaning medium into the transport path, and when the substrate is displaced from the nozzle ejection direction, the cleaning medium is introduced into the transport path and the nozzle 24. The film forming apparatus according to claim 22, further comprising: a control unit that controls the cleaning medium supply unit and the moving unit as derived from the above.   The cleaning means is a cleaning medium supply means for introducing a cleaning medium into the transport path, and a discharge path connected to the transport path, and the cleaning medium introduced into the transport path is the nozzle 24. The film forming apparatus according to claim 22 or 23, including the lead-out path that leads to a different direction from the lead-out path.   The cleaning unit includes a cleaning medium supply unit that introduces a cleaning medium into the conveyance path, and a shielding plate disposed between the nozzle and the substrate, and the shielding plate includes the nozzle and the substrate. 24. The film forming apparatus according to claim 22, wherein a cleaning medium is introduced into the transport path and led out from the nozzle.   27. The film forming apparatus according to claim 24, wherein the cleaning medium is a purge gas.   28. The film forming apparatus according to claim 27, wherein the cleaning means introduces the cleaning medium into the transport path intermittently or while changing the pressure.   27. The film forming apparatus according to claim 24, wherein the cleaning medium is a volatile organic solvent containing alcohol or acetone.   27. The film forming apparatus according to claim 24, wherein the cleaning medium is an aerosol in which particles having a diameter larger than that of the raw material powder used for film formation are dispersed in a gas.   The film forming apparatus according to any one of claims 22 to 30, wherein the cleaning unit further includes a heating unit that heats the conveyance path.   32. The film forming apparatus according to any one of claims 22 to 31, wherein the cleaning unit further includes a vibrating unit that vibrates the transport path.   33. The control unit according to any one of claims 22 to 32, further comprising a control unit that controls the aerosol generating unit to stop transporting the aerosol to the nozzle when the cleaning unit cleans the transport path. Film forming equipment.   The cleaning means controls the aerosol generating means and the suction means so that the suction means operates in a state where suction of the residue in the transport path is stopped and transport of the aerosol to the nozzle is stopped. The film-forming apparatus of Claim 22 or 23 containing the control means to perform. The suction means includes pressure adjusting means for adjusting the pressure in the film forming chamber;
The pressure adjusting means is configured to suck the residue in the transport path into the film forming chamber by evacuating the film forming chamber after the pressure in the film forming chamber is once increased. The film forming apparatus according to claim 34, which is controlled.   36. The film forming apparatus according to claim 35, wherein the pressure adjusting means increases the pressure in the film forming chamber to atmospheric pressure.   37. The control unit controls the moving unit and the suction unit so that the substrate is displaced from the nozzle injection direction and the residue in the transport path is sucked into the film forming chamber. The film-forming apparatus of any one of these.   The cleaning means is a lead-out path connected to the transport path, the lead-out path leading to a direction different from the nozzle, and a means for discharging the residue in the transport path through the lead-out path The film-forming apparatus of Claim 22 or 23 containing these.   The cleaning means includes suction means for sucking residues in the transport path into the film forming chamber, and a shielding plate disposed between the nozzle and the substrate, and the shielding plate includes the nozzle and the nozzle. 24. The film forming apparatus according to claim 22 or 23, wherein a residue in the transport path is sucked into the film forming chamber from the nozzle when being disposed between the substrate and the substrate. The aerosol generating means,
A powder storage chamber in which an opening for leading out the stored powder is formed;
Gas supply means for supplying a gas for dispersing the powder derived from the opening;
The film-forming apparatus of any one of Claims 21-39 containing this.   The aerosol generating means is rotated from the opening having a groove having a predetermined width and depth formed on the circumference facing the opening, and rotated to rotate the rotating body to the groove. 41. The film forming apparatus according to claim 40, further comprising a transport unit that transports the arranged powder to a position of the gas supply means.

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