JP2013128875A - Liquid material coating device and cleaning method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently clean inside in a liquid material coating device.SOLUTION: A liquid supply channel 7 introduces a liquid material from a liquid material storage tank 5 or a cleaning liquid from a cleaning liquid storage tank 10 into an atomizer (two fluid spray nozzles) of a spraying unit 4. A flow path switching mechanism 14 switches a connection to the liquid supply channel 7 from the liquid material storage tank 5 to the cleaning liquid storage tank 10 at cleaning. As a result, the atomizer atomizes the introduced cleaning liquid and sprays it to a cleaning object area.

Description

  The present invention relates to a liquid material application device that applies a liquid material to a substrate by spraying the liquid material atomized using an atomizer represented by a spray nozzle or the like onto the substrate surface, and in particular, the liquid material application device. It is related with the cleaning inside.

  A thin film manufacturing method for forming a thin film on the surface of a substrate by applying a liquid material to the substrate and performing drying, baking, etc. is widely used, such as a spray method, a dipping method, a slit coating method, and a spin coating method. It is a technique.

  In addition, the size of the substrate on which the thin film is formed is increasing year by year, and there is an increasing demand for accurately forming the thin film on the surface of the large substrate at low cost.

  Among the thin film manufacturing methods mentioned above, it is said that the dipping method and the spin coating method are difficult to cope with a large substrate mainly in terms of the substrate weight. In addition, in the slit coating method, there are many problems regarding accuracy when dealing with a large substrate, and the device cost becomes high when dealing with a large substrate.

  Among them, the spray method is not limited by the weight of the substrate even when dealing with large substrates, so by installing multiple inexpensive spray nozzles, a spray-type thin film manufacturing device that can accommodate large substrates is realized at a relatively low cost. It can be said that this is possible.

  In a thin film manufacturing apparatus that manufactures a thin film on a substrate by spraying an atomized liquid material using a spray nozzle, the material utilization efficiency often does not reach about 30%. For this reason, the liquid material that has not contributed to the film formation is discharged together with the exhaust gas, or adheres to unintended portions such as the spray nozzle, the periphery thereof, and the inner wall that covers the spraying portion.

  When the liquid material adheres to the spray nozzle (including the periphery thereof), the inner wall of the spraying portion, or the like, the solid material is deposited by drying and is deposited. As a result, problems such as a decrease in atomization performance of the spray nozzle and a decrease in film quality due to particles falling on the film formation substrate are caused, and replacement or cleaning of members constituting the apparatus is required. This leads to a reduction in continuous operation time of the apparatus, that is, productivity.

  The adhesion of the liquid material as described above appears more prominently in the process of continuous thin film production. As a result, the accumulation of the solidified liquid material further proceeds on the spray nozzle and the inner wall of the spraying portion.

  Therefore, in order to manufacture a high-quality thin film at low cost with high productivity, it is essential to establish a maintenance method that does not involve efficient cleaning of the inner wall covering the spray nozzle and the spraying part and stop of the apparatus.

  In such a technical background, it is conceivable to apply the cleaning method described in Patent Document 1 to the cleaning of the thin film manufacturing apparatus as described above. This Patent Document 1 describes a method in which a nozzle tip is cleaned by flowing a cleaning liquid through a gas ejection channel of a nozzle. Accordingly, the nozzle can be cleaned without using a special cleaning device.

JP 9-29155 A (published February 4, 1997)

  However, the cleaning method described in Patent Document 1 only removes deposits adhering to the tip of the nozzle, and other parts such as the inner wall of the spraying part and the inside of the flow path of the liquid material such as the inside of the nozzle. It cannot be washed.

  In order to improve productivity and reduce maintenance costs, it is required not to stop the apparatus and disassemble / remove parts to be cleaned for the above cleaning.

  In this way, a method has not yet been established that can clean all parts where particles are likely to adhere, such as the inside of the liquid material flow path, the nozzle tip, and the inner wall of the spraying part, with efficient and minimal equipment stoppage and maintenance costs. There is a problem.

  In addition, production is continued while performing cleaning without stopping the apparatus in a short cycle by such a method, and then cleaning / replacement by an operator in a long cycle is also performed. However, the cleaning and replacement of parts by the worker is based on the premise that the surface temperature of the area sprayed with the liquid material is lowered to a temperature at which the worker can perform the work.

  Usually, since the temperature in this region is 300 ° C. or higher, there is a problem that it takes time to sufficiently reduce the temperature and the downtime of the apparatus becomes long.

  The present invention has been made in view of the above problems, and an object thereof is to establish an apparatus configuration and a cleaning method for efficiently cleaning the inside of a liquid material coating apparatus.

  In order to solve the above-described problems, a liquid material application apparatus according to the present invention atomizes the liquid material supplied from a liquid material storage tank that stores the liquid material by an atomizer and applies the liquid material to a substrate. In the apparatus, in order to solve the above-described problem, a cleaning liquid storage tank that stores a cleaning liquid, and an introduction flow that introduces the liquid material from the liquid material storage tank or the cleaning liquid from the cleaning liquid storage tank into the atomizer. And a flow path switching means for switching between the liquid material storage tank and the cleaning liquid storage tank and connecting to the introduction flow path.

  In the above configuration, the connection of the cleaning liquid storage tank or the liquid material storage tank to the introduction flow path is switched by the cleaning flow path switching means. Thus, when the liquid material is sprayed on the substrate, the liquid material storage tank is connected to the introduction flow path so that the liquid material is supplied to the atomizer, and at the time of cleaning, the cleaning liquid is supplied to the atomizer. The cleaning liquid storage tank is connected to the introduction flow path. Therefore, at the time of cleaning, the cleaning liquid can be sprayed by supplying the cleaning liquid to the atomizer instead of the liquid material. As a result, the inside of the introduction flow path is cleaned by the flow of the cleaning liquid through the introduction flow path. In addition, the atomized cleaning liquid is sprayed on and around the ejection part of the atomizer, so that the deposits attached to these parts are washed away.

  In addition, if the atomizer sucks up the liquid by itself, a mechanism for feeding the cleaning liquid to the atomizer is unnecessary. Such an atomizer can suck and atomize the cleaning liquid and clean the region to be cleaned.

  The liquid material application device preferably further includes a cleaning atomizer that is used only while the cleaning liquid storage tank is connected to the introduction flow path.

  The cleaning atomizer does not contribute to film formation, and atomizes the cleaning liquid only during cleaning. Thus, more cleaning liquid can be atomized in a short time during cleaning. Therefore, efficient cleaning in a short time can be realized.

  In the liquid material application apparatus, it is preferable that the cleaning atomizer is disposed so as to spray the cleaning liquid toward the cleaning target region.

  In the above configuration, since the cleaning atomizer sprays the cleaning liquid toward the cleaning target region, cleaning can be performed more effectively. Since this cleaning atomizer does not contribute to film formation, it is not necessary to atomize toward the substrate, and the cleaning liquid may be sprayed in a direction suitable for cleaning.

  In the liquid material application device, it is preferable that the cleaning liquid storage tank stores at least two types of the cleaning liquid, and the cleaning liquid is switched and supplied to the introduction flow path at the time of cleaning.

  Thereby, various washing | cleaning can be performed using at least 2 types of washing | cleaning liquid. For example, a liquid that does not contain a solid content but is close to a liquid material as a solvent can be used as the first cleaning liquid, and then sufficient cleaning can be performed with a second cleaning liquid made of a minority solvent species. Therefore, when pure water is used as the second cleaning liquid, for example, the temperature drop in the liquid material application region can be promoted in order to allow the operator to work.

  If the replacement is performed with a cleaning liquid such as the second cleaning liquid from the beginning, the above-mentioned problem that solids may precipitate due to mixing with the actual solution of the liquid material may occur. It is preferable to perform the two-stage cleaning according to.

  In the liquid material coating apparatus, the cleaning liquid is preferably a liquid composed of a part or all of the liquid used as a solvent for the liquid material.

  As a result, as described above, it is effective in suppressing precipitation of solids caused by mixing different types of solvents in the cleaning liquid with the liquid material remaining inside the introduction flow path, clogging of the atomizer due to the precipitation, and the like. There is.

  The liquid material applicator guides a drain pump for discharging the cleaning liquid supplied from the introduction flow path, and direct discharge of the cleaning liquid discharged from the drain pump to the spraying portion of the atomizer. It is preferable to further include a drainage flow path and a drainage tank that collects the cleaning liquid discharged from the drainage flow path.

  As a result, at the time of cleaning, when the cleaning liquid supplied from the introduction flow path is discharged by the drainage pump, it is discharged to the spraying part of the atomizer through the discharge flow path and used for cleaning, and then into the drainage tank. To be recovered. Thereby, at the time of cleaning, the liquid material remaining in the introduction flow path can be quickly discharged, and a large amount of cleaning liquid can be introduced in a short time. Therefore, cleaning can be performed more efficiently and effectively.

  In the cleaning method for a liquid material application apparatus according to the present invention, the liquid material supplied from a liquid material storage tank that stores the liquid material is atomized by an atomizer and applied to the substrate. In the method, in order to solve the above-described problem, the cleaning liquid from the cleaning liquid storage tank that stores the cleaning liquid is supplied to the introduction flow path that introduces the liquid material from the liquid material storage tank into the atomizer at the time of cleaning. It is characterized by including a cleaning liquid introducing step for switching and introducing, and an atomizing step for atomizing the introduced cleaning liquid by the atomizer.

  In the above configuration, at the time of cleaning, the cleaning liquid from the cleaning liquid storage tank is introduced into the introduction flow path by the cleaning liquid introduction process, and the introduced cleaning liquid is atomized by the atomizer in the atomization process. Thus, at the time of cleaning, the cleaning liquid can be sprayed by supplying the cleaning liquid to the atomizer instead of the liquid material. As a result, the atomized cleaning liquid is sprayed on and around the jetting part of the atomizer, so that the deposits attached to these parts are washed away.

  In the cleaning method of the liquid material application apparatus, it is preferable that the cleaning liquid introduction step switches the connection to the introduction flow path from the liquid material storage tank to the cleaning liquid storage tank.

  Thus, at the time of cleaning, the cleaning liquid can be atomized simply by switching the connection of the tank to the introduction flow path, so that the cleaning liquid can be easily introduced into the introduction flow path.

  In the cleaning method of the liquid material application apparatus, the atomization step is performed by using the cleaning atomizer that atomizes only the cleaning liquid together with the atomizer used for applying the liquid material. Is preferable.

  Thereby, the cleaning atomizer does not contribute to the film formation and atomizes the cleaning liquid only at the time of cleaning. Thereby, at the time of washing | cleaning, more washing | cleaning liquid can be atomized in a short time with the atomizer and the atomizer for washing | cleaning. Therefore, efficient cleaning can be realized.

  In the cleaning method of the liquid material coating apparatus, the cleaning liquid introduction step uses two types of first cleaning liquid and second cleaning liquid as the cleaning liquid, and after introducing the first cleaning liquid, the second cleaning liquid is used. It is preferable to introduce by switching.

  Thereby, various washing | cleaning can be performed using two types of washing | cleaning liquids. For example, a liquid that does not contain a solid content but is close to a liquid material as a solvent can be used as the first cleaning liquid, and then sufficient cleaning can be performed with a second cleaning liquid made of a minority solvent species. Therefore, when pure water is used as the second cleaning liquid, for example, the temperature drop in the liquid material application region can be promoted in order to enable the operator to perform work.

  If the replacement is performed with a cleaning liquid such as the second cleaning liquid from the beginning, the above-mentioned problem that solids may precipitate due to mixing with the actual solution of the liquid material may occur. It is preferable to perform the two-stage cleaning according to.

  The liquid material applicator according to the present invention, which is configured as described above, has an effect that the inside of the liquid material applicator can be efficiently cleaned. Specifically, according to the present invention, not only the deposition of deposits due to the liquid material but also the liquid material coating apparatus such as the spray CVD method and the mist CVD method can be cleaned with the cleaning liquid. Thus, it is possible to establish a cleaning method capable of promoting a temperature decrease in the region cleaned with the cleaning liquid. In addition, the maintenance frequency can be reduced and the downtime of the liquid material application device can be shortened.

It is a side view which shows the structure of the mist CVD film-forming apparatus which concerns on two embodiment of this invention. It is a perspective view which shows the internal structure of the spraying part in the said mist CVD film-forming apparatus which concerns on one Embodiment of this invention. It is a perspective view which shows the internal structure of the spraying part in the mist CVD film-forming apparatus which concerns on other embodiment of this invention.

[Embodiment 1]
An embodiment according to the present invention will be described below with reference to FIGS. 1 and 2.

  As an embodiment for carrying out the present invention, film formation by a mist CVD film forming apparatus using a two-fluid spray nozzle will be described as an example.

[Configuration of mist CVD film forming system]
FIG. 1 is a side view showing a configuration of a mist CVD film forming apparatus according to the present embodiment. FIG. 2 is a perspective view showing the internal structure of the spraying part in the mist CVD film forming apparatus.

  As shown in FIG. 1, a mist CVD film forming apparatus 100 is a thin film manufacturing apparatus (liquid material applying apparatus) for forming a thin film by atomizing and applying a liquid material to a substrate 101 (substrate). is there. The mist CVD film forming apparatus 100 includes a mounting table 1, a heating furnace 2 for heating the substrate substrate 101, a transport mechanism 3, a spraying unit 4, a liquid material storage tank 5, a liquid supply path 7, a cleaning liquid storage tank 10, and a first flow path. 12, a second flow path 13, a flow path switching mechanism 14, and a control unit 15.

  The mounting table 1 is a table on which the substrate 101 is mounted so as to face a spraying unit 4 described later. The heating furnace 2 is a furnace for heating the substrate 101 in order to dry the liquid material sprayed onto the substrate 101 by the spraying unit 4.

  The transport mechanism 3 is a mechanism that transports the mounting table 1 in the X direction, and includes a mesh belt 3a and a plurality of rollers 3b that drive the mesh belt 3a. The transport mechanism 3 drives the mounting table 1 in the X direction when the spraying unit 4 performs a film forming process on the substrate 101.

  The liquid material storage tank 5 stores a liquid material that is a film forming material for forming a film on the substrate 101. As the liquid material, a solution in which a metal chloride is dissolved in pure water and hydrochloric acid is used.

  The cleaning liquid storage tank 10 stores a cleaning liquid for cleaning the deposits that the liquid material has dried and adhered inside the mist CVD film forming apparatus 100. As the cleaning liquid, dilute hydrochloric acid having a volume concentration of about 5% is used. There are two reasons for this. The first reason is that hydrochloric acid can dissolve deposits. The second reason is that when pure water is used as the cleaning liquid, the pure material and the liquid material composed of the above components are mixed, and the liquid material may gel and cause clogging of the flow path. is there.

  Thus, a liquid composed of a part of the liquid (hydrochloric acid) used as the solvent for the liquid material is used for the cleaning liquid. Moreover, the liquid comprised by all the liquids (hydrochloric acid) used as said solvent may be used for a washing | cleaning liquid.

  The liquid supply path 7 (introduction flow path) is a flow path for supplying (introducing) the liquid material or the cleaning liquid to the two-fluid spray nozzle 6 of the spray unit 4 described later.

  The first flow path 12 is a flow path for supplying the liquid material and CDA discharged from the liquid material storage tank 5. The second flow path 13 is a flow path for supplying the cleaning liquid discharged from the cleaning liquid storage tank 10.

  The flow path switching mechanism 14 (flow path switching means) is a mechanism that switches between the first flow path 12 and the second flow path 13 and connects to the liquid supply path 7. The flow path switching mechanism 14 includes, for example, a flow path switching valve and an actuator that drives the flow path switching valve.

  The control unit 15 is a device that controls the switching operation of the flow path switching mechanism 14, and includes a microprocessor and a memory. The controller 15 switches the flow path switching mechanism 14 so as to connect the liquid supply path 7 and the first flow path 12 during film formation, and to connect the liquid supply path 7 and the second flow path 13 during cleaning. Control the behavior.

  As shown in FIG. 2, the spray unit 4 includes a plurality of two-fluid spray nozzles 6, a spray unit inner wall 9, and a housing 16.

  The two-fluid spray nozzle 6 (atomizer) is housed in a box-shaped housing 16 and has a constant interval in a direction orthogonal to the transport direction (X direction) of the substrate 101 in the horizontal plane. And are arranged in a row (straight line). Only the tip portion 6a (spouting portion) of the two-fluid spray nozzle 6 protrudes downward from a hole provided in the bottom surface of the spraying portion 4, and the mist sprayed from the selection portion 6a is below the spraying portion 4. Sprayed toward.

  As the two-fluid spray nozzle 6, a fine fog generating nozzle (BIMV8002S) manufactured by Ikeuchi Co., Ltd. is used. This fine mist generation nozzle is a so-called suction type nozzle that can suck up the liquid and mist itself, so that a mechanism for feeding the liquid material to the two-fluid spray nozzle 6 is not required. it can.

  A liquid supply path 7 and a CDA supply path 8 drawn from the outside of the spray unit 4 are connected to the two-fluid spray nozzle 6. The two-fluid spray nozzle 6 mixes the liquid material supplied from the liquid material storage tank 5 through the liquid supply path 7 and dry air (CDA: Clean Dry Air) supplied from the outside through the CDA supply path 8. Generate mist. Dry air is supplied from a CDA supply source (not shown).

  The spraying portion inner wall 9 is provided to rectify the flow of the mist ejected from the two-fluid spray nozzle 6. This rectification is intended to suppress the generation of turbulent flow due to the negative pressure generated inside the spraying part 4 due to the mist spraying by the two-fluid spray nozzle 6.

  In the present embodiment, the two-fluid spray nozzles 6 arranged in a straight line are covered as a whole by the inner wall 9 of the spraying portion, but a structure in which the two-fluid spray nozzles 6 are individually covered may be used.

[Film deposition by mist CVD film deposition system]
Subsequently, a film forming procedure by the mist CVD film forming apparatus 100 will be described.

<Outline of deposition operation>
First, the substrate 101 placed on the mounting table 1 is transported into the heating furnace 2 and heated until reaching a predetermined substrate surface temperature during transport. Then, when the board | substrate 101 reaches directly under the spraying part 4, spraying of the liquid material by the 2 fluid spray nozzle 6 is started. At this time, the mist generated by the two-fluid spray nozzle 6 is sprayed on the substrate 101 and baked, thereby contributing to the generation of the thin film.

  Then, when the board | substrate 101 comes out from directly under the spraying part 4, spraying of a liquid material is stopped. Further, the substrate 101 is transported to the outlet of the heating furnace 2 and the film forming operation is completed.

<Adhesion of foreign matter and its effects>
When a thin film is formed on the substrate 101 by the mist CVD film forming apparatus 100, foreign matter adheres to the formed substrate 101 as the number of film formation increases. This has been found to be a deposit of the solid content of the liquid material and its intermediate product. Part of the mist sprayed by the two-fluid spray nozzle 6 reaches the surface of the substrate 101 and contributes to the formation of the thin film as described above, while the remaining most is discharged to the outside together with the exhaust. However, a part of the mist that has not been discharged to the outside adheres to the periphery of the tip portion 6 a serving as the outlet of the two-fluid spray nozzle 6 and the inner wall 9 of the spray portion. If the deposit falls on the surface of the substrate 101 during film formation, the above-mentioned foreign matter adheres.

  Specifically, when the amount of liquid material sprayed on the substrate 101 as mist reaches about 40 L, fine particles can be confirmed on the surface of the substrate 101 on which the film has been formed. Then continue to increase. The adhesion of particles to the surface of the substrate 101 is a phenomenon that should be avoided because it leads to film quality degradation.

  Conventionally, the period until the phenomenon of particle adhesion occurs is the period in which the apparatus can be used continuously. When the amount of liquid material reaches 40L, maintenance work such as disassembly, cleaning, and reassembly of the spraying part is performed to operate the apparatus again. I was doing the work. Naturally, maintenance work such as disassembly, cleaning, and reassembly of the spraying portion (spray nozzle) requires work time. Also, during film formation, it is necessary to wait until the temperature of the sprayed part exposed to high temperature falls to a workable temperature, and to increase the temperature again after the work, which causes longer downtime of the apparatus. It has become.

  In addition, the deposits adhering to the periphery of the tip portion 6a of the two-fluid spray nozzle 6 may cause a decrease or deterioration of the mist formation performance of the two-fluid spray nozzle 6 in addition to the generation of particles. Specific examples of the decrease or deterioration of the mist formation performance include a decrease in the liquid material to be mist, a decrease in the CDA ejection amount, and a change in the particle diameter of the generated mist.

  For these reasons, it can be said that in the mist CVD film forming apparatus 100, it is important to clean the front end portion 6a of the two-fluid spray nozzle 6 and its periphery.

<Switching of flow path>
In the present embodiment, the control of the control unit 15 switches the connection of the liquid material storage tank 5 or the cleaning liquid storage tank 10 to the liquid supply path 7 as follows. At the time of normal film formation, the liquid supply path 7 connected to the two-fluid spray nozzle 6 is connected to the first flow path 12 connected to the liquid material storage tank 5. On the other hand, when the amount of the liquid material reaches 40 L during film formation, the liquid supply path 7 is connected to the second flow path 13 connected to the cleaning liquid storage tank 10 (cleaning liquid introduction process). After this switching, the cleaning liquid introduced into the two-fluid spray nozzle 6 is atomized by being mixed with CDA by the two-fluid spray nozzle 6 (atomization step).

  By continuing the spray of about 2 L of the cleaning liquid, the deposits adhering to the periphery of the tip portion 6a of the two-fluid spray nozzle 6 and the spraying portion inner wall 9 are dissolved and dropped to be removed. Further, when the cleaning liquid flows through the liquid supply path 7, the inside of the liquid supply path 7 is cleaned.

  After the cleaning liquid spray, when the liquid supply path 7 is connected to the first flow path 12 again, the liquid material flows into the liquid supply path 7. Thereby, the liquid material can be sprayed again by the two-fluid spray nozzle 6.

  For the switching control described above, the liquid material storage tank 5 is provided with a first sensor for detecting the amount of liquid material discharged during one film formation, while the cleaning liquid storage tank 10 has one cleaning. A second sensor is provided to detect the amount of cleaning liquid that is sometimes discharged. When the amount of liquid material detected by the first sensor reaches 40L, the control unit 15 connects the liquid supply path 7 to the first flow path 12, and when the amount of cleaning liquid detected by the second sensor reaches 2L, The above switching control is performed so that the supply path 7 is connected to the second flow path 13.

  When such an operation was actually executed by the mist CVD film forming apparatus 100, the deposits adhering to the periphery of the front end portion 6a of the two-fluid spray nozzle 6 and the inner wall 9 of the spraying portion decreased. As a result, when normal film formation was performed after cleaning, particle adhesion to the film formation surface of the substrate 101 was not confirmed. By performing cleaning by this method, the amount of liquid material that requires disassembly and cleaning of the spray unit 4 and the two-fluid spray nozzle 6 could be increased from about 40 L to about 150 L.

  As described above, according to the internal cleaning method of the mist CVD film forming apparatus 100 according to the present embodiment, the frequency of disassembling and cleaning the spray unit 4 and the two-fluid spray nozzle 6 can be reduced to about 1/4 of the conventional method. Therefore, the operating time of the mist CVD film forming apparatus 100 can be increased and the productivity of the thin film can be improved.

[Modification]
Then, the modification of this embodiment is demonstrated.

  As shown in FIG. 1, a mist CVD film forming apparatus 100 according to a modification of the present embodiment may include a drain pump 17, a drain channel 18, and a drain tank 19.

  The drainage pump 17 is a pump that forcibly discharges the cleaning liquid supplied from the liquid supply path 7. The drainage pump 17 is controlled by the control unit 15 so as to operate when the spraying unit 4 is cleaned.

  The drainage flow path 18 is a flow path that guides and discharges the cleaning liquid discharged from the drainage pump 17 to the spraying unit 4. The drainage flow path 18 is arranged so that the discharge port is directed to the distal end portion 6a of the two-fluid spray nozzle 6 and the spraying portion inner wall 9 that are to be cleaned. As a result, the cleaning liquid can be discharged to the tip end portion 6 a and the spraying portion inner wall 9.

  The drainage tank 19 is a tank for collecting the cleaning liquid discharged to the tip end portion 6 a and the spraying portion inner wall 9 by the drainage flow path 18. The drainage tank 19 is disposed below the spray unit 4 and the transport mechanism 3.

  In the above configuration, at the time of cleaning, the cleaning liquid supplied from the liquid supply path 7 is forcibly discharged to the spray unit 4 through the drain flow path 18 by the drain pump 17. The cleaning liquid is not sprayed by the two-fluid spray nozzle 6 but is directly discharged from the drainage flow path 18 to the distal end portion 6 a and the spraying portion inner wall 9. The cleaning liquid used for cleaning in this way passes through the mesh belt 3a and is collected in the drain tank 19 as waste liquid.

  As a result, a large amount of cleaning liquid is supplied to the spraying section 4 in a short time, and the front end portion 6 a and the spraying section inner wall 9 can be strongly cleaned by the cleaning liquid discharged from the drainage flow path 18. Therefore, cleaning can be performed more efficiently and effectively.

  Further, the liquid material remaining in the liquid supply path 7 can be forcibly discharged by the drain pump 17 during the transition from film formation to cleaning. Thereby, the shift to cleaning can be performed quickly. Therefore, cleaning can be performed more efficiently.

  It is needless to say that the above modification can also be applied to Embodiment 2 described later.

[Embodiment 2]
Another embodiment according to the present invention will be described below with reference to FIGS. 1 and 3.

  As another embodiment for carrying out the present invention, film formation by a mist CVD film forming apparatus using a two-fluid spray nozzle will be described as an example.

[Configuration of mist CVD film forming system]
FIG. 1 is a side view showing a configuration of a mist CVD film forming apparatus according to the present embodiment. FIG. 3 is a perspective view showing an internal structure of a spraying portion in the mist CVD film forming apparatus.

  In the present embodiment, components having functions equivalent to those of the components in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 1, the mist CVD film forming apparatus 100 includes a heating furnace 2, a transport mechanism 3, a liquid material storage tank 5, a liquid supply path 7, a cleaning liquid storage tank 10, a first flow path 12, a second flow path 13, A flow path switching mechanism 14, a control unit 15, and a spraying unit 21 are provided.

  As shown in FIG. 3, the spray unit 21 is configured by adding two cleaning two-fluid spray nozzles 11 to the spray unit 4 described above.

  The cleaning two-fluid spray nozzle 11 (cleaning atomizer) is a two-fluid spray nozzle that is used only during cleaning without ejecting either liquid material or CDA during normal film formation. The two-fluid spray nozzles 11 for cleaning are aligned in the same manner as the two-fluid spray nozzles 6 and are arranged at both ends of the row composed of the two-fluid spray nozzles 6. Further, the two-fluid spray nozzle 11 for cleaning is installed such that the tip end portion 11a (spouting portion) sprays toward the inner walls (spraying portion inner walls 9) at both ends of the spraying portion 4 which is a region to be cleaned.

  An opening / closing valve (not shown) is opened in the flow path from the liquid supply path 7 to the cleaning two-fluid spray nozzle 11 so that the cleaning two-fluid spray nozzle 11 sprays the cleaning liquid only at the time of cleaning. ) Is provided. The control of the opening / closing of the on / off valve is performed by the control unit 15.

  In this embodiment, the cleaning two-fluid spray nozzle 11 is composed of the same model BIMV8002S as the film-forming two-fluid spray nozzle 6, but may be composed of other models.

  Further, the number, installation location, and direction of the cleaning two-fluid spray nozzle 11 are not limited to the above example, but are determined according to the location where cleaning is prioritized.

[Cleaning by mist CVD film forming equipment]
<Cleaning using a two-fluid spray nozzle for cleaning>
The film forming procedure by the mist CVD film forming apparatus 100 configured as described above is the same as the film forming procedure by the mist CVD film forming apparatus 100 of the first embodiment. Therefore, the description is omitted in this embodiment. Here, a cleaning procedure by the mist CVD film forming apparatus 100 different from the first embodiment will be described.

  In the mist CVD film forming apparatus 100 of the present embodiment, when the amount of the liquid material sprayed onto the substrate 101 reaches about 40 L, first, as in the mist CVD film forming apparatus 100 of the first embodiment, the liquid supply path 7 Is switched from the first flow path 12 to the second flow path 13. Thereby, since the liquid supply path 7 is connected to the cleaning liquid storage tank 10, the cleaning liquid is supplied to the spraying unit 4. The cleaning liquid used here is also dilute hydrochloric acid having a volume concentration of about 5%, like the cleaning liquid used in the first embodiment.

  Next, mist spraying by the cleaning two-fluid spray nozzle 11 is started together with the two-fluid spray nozzle 6 by using the cleaning liquid supplied through the liquid supply path 7. Thus, the two-fluid spray nozzle 6 not only performs cleaning similar to the mist CVD film forming apparatus 100 of the first embodiment, but also performs cleaning by the cleaning two-fluid spray nozzle 11. Again, a total of about 2 L of cleaning liquid is sprayed to clean the periphery of the tip end portion 6 a of the two-fluid spray nozzle 6 and the sprayed portion inner wall 9.

  When film formation is continued after the above cleaning, the connection to the liquid supply path 7 is switched from the second flow path 13 to the first flow path 12 as in the first embodiment. Thereby, the liquid material is supplied to the spraying unit 4 through the liquid supply path 7.

  As described above, the mist CVD film forming apparatus 100 of this embodiment uses the cleaning two-fluid spray nozzle 11 for cleaning. Thereby, it is possible to spray a larger amount of cleaning liquid in a wider range in a shorter time than the mist CVD film forming apparatus 100 of the first embodiment. Therefore, the inside of the spraying part 4 can be cleaned more efficiently and effectively.

<Disassembly and cleaning of spray section>
Next, disassembly and cleaning of the spray unit 4 and the two-fluid spray nozzle 6 will be described.

  In order to perform disassembly cleaning of the spray unit 4 and the two-fluid spray nozzle 6, it is necessary to remove the spray unit 4 from the mist CVD film forming apparatus 100 and disassemble it. For that purpose, as mentioned above, the temperature of the spraying part 4 must fully fall, and the time for about 5 hours is required for the temperature fall.

  In the present embodiment, in order to accelerate the temperature drop of the spraying section 4, cleaning with pure water is performed after the cleaning with hydrochloric acid. For this reason, as the cleaning liquid storage tank 10, a cleaning liquid storage tank 10 in which hydrochloric acid is stored and a cleaning liquid storage tank 10 in which pure water is stored are prepared separately. Then, when the cleaning liquid is switched from hydrochloric acid to pure water, the two cleaning liquid storage tanks 10 may be exchanged, and the flow path for discharging the cleaning liquid from the two cleaning liquid storage tanks 10 and the second flow path 13 are connected. It may be switched.

  Since the deposit to be cleaned is dissolved by pure water, it can be cleaned with pure water. However, since there is a problem of gelation as described in the first embodiment, the first cleaning liquid is acidic. Hydrochloric acid must be used. Similarly, it is possible to use hydrochloric acid as the second cleaning liquid. However, since a large amount of hydrogen chloride gas is generated by the vaporization of hydrochloric acid, the use of hydrochloric acid as the second cleaning liquid should be avoided. Therefore, in order to avoid the problem of gelation, dilute hydrochloric acid is used as the first washing liquid, and after the inside of the liquid supply path 7 is sufficiently replaced with dilute hydrochloric acid, it is washed again with pure water as the second washing liquid, It can be said that it is reasonable to reduce the time required for the temperature decrease of 4.

  In addition, although two types of 1st and 2nd washing | cleaning liquids are used for said washing | cleaning, you may use other washing | cleaning liquids as needed. In this case, it is necessary to prepare a cleaning liquid storage tank 10 for the additional cleaning liquid.

  After cleaning with hydrochloric acid, pure water is sprayed on the inner wall 9 of the spraying portion 4 and the like by performing mist spraying of pure water with the two-fluid spray nozzle 11 together with the two-fluid spray nozzle 6 again. By washing with pure water, the hydrochloric acid used for the previous washing is washed away, so that the safety of the next process by the operator can be secured and the heat of the spraying section 4 is taken away by the heat of vaporization of the sprayed pure water. Therefore, the time required for the temperature drop of the spraying part 4 can be shortened.

  In the mist CVD film forming apparatus 100 of the present embodiment, when pure water is actually sprayed by the two-fluid spray nozzle 6 and the two-fluid spray nozzle 11 for cleaning, a waiting time of 5 hours that has been required so far for the temperature drop. Was reduced to 3 hours.

  As described above, according to the internal cleaning method of the mist CVD film forming apparatus 100 of this embodiment using at least two types of cleaning liquids, the frequency of disassembling and cleaning the spray unit 4 and the two-fluid spray nozzle 6 is set to 1/4 of the conventional frequency. Can be reduced to a certain extent. Moreover, since the time required for the temperature drop of the spraying part 4 is shortened, the operating time of the mist CVD film-forming apparatus 100 can be increased and the productivity of the thin film can be improved.

  Of course, the above-described cleaning method using the two types of cleaning liquid can also be applied to the mist CVD film forming apparatus 100 of the first embodiment.

[Additional Notes]
The present invention is not limited to the first and second embodiments described above, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  In the first and second embodiments, the example in which the present invention is applied to the mist CVD film forming apparatus 100 has been described. However, the present invention is not limited to the mist CVD film forming apparatus 100, and any liquid material application may be applied to the substrate by atomizing the liquid material using an atomizer such as the two-fluid spray nozzle 6. Of course, the present invention can also be applied to an apparatus such as a spray CVD film forming apparatus.

  The present invention relates to an internal cleaning of a liquid material coating apparatus that sprays and sprays an atomized liquid material onto a substrate surface, and in particular, there is a problem of deterioration in spray performance and film quality due to a large amount of deposits adhering during the application of the liquid material. It can be suitably used for the mist CVD method and the spray CVD method. The present invention is suitable for thin film manufacturing apparatuses such as a mist CVD method and a spray CVD method, but can be applied to various liquid material application apparatuses that atomize and apply a liquid material containing a solid component. It can be said. Furthermore, since the maintenance frequency can be reduced and the time required for the maintenance can be reduced, the present invention can contribute to the reduction of the downtime of the liquid material coating apparatus, that is, the improvement of productivity.

DESCRIPTION OF SYMBOLS 1 Mounting stand 2 Heating furnace 3 Conveyance mechanism 4 Spraying part 5 Liquid material storage tank 6 2 fluid spray nozzle (atomizer)
6a Tip (spout)
7 Liquid supply path (introduction channel)
8 CDA supply path 9 Inner wall of spraying part 10 Cleaning liquid storage tank 11 Two-fluid spray nozzle for cleaning (cleaning atomizer)
11a Tip (spout)
12 1st flow path 13 2nd flow path 14 Flow path switching mechanism (flow path switching means)
DESCRIPTION OF SYMBOLS 15 Control part 16 Housing | casing 17 Drainage pump 18 Drainage flow path 21 Spraying part 19 Drainage tank 100 Mist CVD film-forming apparatus (liquid material application apparatus)
101 substrate

Claims (10)

In a liquid material application apparatus that atomizes the liquid material supplied from a liquid material storage tank that stores liquid material by an atomizer and applies the liquid material to a substrate.
A cleaning liquid storage tank for storing the cleaning liquid;
An introduction flow path for introducing the liquid material from the liquid material storage tank or the cleaning liquid from the cleaning liquid storage tank into the atomizer;
A liquid material application device comprising: a flow path switching means for switching between the liquid material storage tank and the cleaning liquid storage tank and connecting to the introduction flow path.   The liquid material application apparatus according to claim 1, further comprising a cleaning atomizer that is used only while the cleaning liquid storage tank is connected to the introduction flow path.   The liquid material application apparatus according to claim 2, wherein the cleaning atomizer is arranged to spray the cleaning liquid toward a region to be cleaned. The cleaning liquid storage tank stores at least two types of the cleaning liquid,
4. The liquid material coating apparatus according to claim 1, wherein the cleaning liquid is switched and supplied to the introduction flow path during cleaning. 5.   5. The liquid material coating apparatus according to claim 1, wherein the cleaning liquid is a liquid composed of a part or all of a liquid used as a solvent for the liquid material. A drainage pump for discharging the cleaning liquid supplied from the introduction flow path;
A drainage flow path for directing the cleaning liquid discharged from the drainage pump to be directly discharged to the ejection part of the atomizer;
The liquid material coating apparatus according to claim 1, further comprising a drain tank that collects the cleaning liquid discharged from the drain passage. In a cleaning method for cleaning the inside of a liquid material application device that atomizes the liquid material supplied from a liquid material storage tank that stores the liquid material by an atomizer and applies the liquid material to a substrate,
A cleaning liquid introduction step of switching and introducing the cleaning liquid from the cleaning liquid storage tank for storing the cleaning liquid into the introduction flow path for introducing the liquid material from the liquid material storage tank into the atomizer at the time of cleaning;
And a nebulization step of atomizing the introduced cleaning liquid by the atomizer.   8. The cleaning method for a liquid material application apparatus according to claim 7, wherein in the cleaning liquid introduction step, the connection to the introduction flow path is switched from the liquid material storage tank to the cleaning liquid storage tank.   The said atomization process atomizes the said washing | cleaning liquid using the atomizer for washing | cleaning which atomizes only the said washing | cleaning liquid with the said atomizer used for application | coating of the said liquid material. Or a method of cleaning a liquid material application device according to 8;   The cleaning liquid introduction step uses two kinds of first cleaning liquid and second cleaning liquid as the cleaning liquid, and after introducing the first cleaning liquid, the second cleaning liquid is switched and introduced. Item 10. The cleaning method for a liquid material application apparatus according to any one of Items 7 to 9.

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