TWI412407B - Reduced pressure drying apparatus - Google Patents

Abstract

To offer a reduced pressure drying apparatus that enables reduction in processing time with simplified configuration and control by preventing a low temperature portion that will lead to condensation from occurring inside a chamber and an exhaust duct. A reduced pressure drying apparatus 10 includes an upper chamber 12, a lower chamber 14, an exhaust duct 32, a decompression pump 28, a partition sheet member 16, a hot air generator 20, and a hot air introduction duct 34. The exhaust duct 32 is configured to be connected to an inner space defined by the upper and lower chambers 12, 14. The decompression pump 28 is configured to decrease pressure of the inner space through the exhaust duct 32. The partition sheet member 16 is configured to create a closed space surrounding at least the exhaust duct 32 and a connection portion of the upper and lower chambers 12, 14 to the exhaust duct 32. The hot air generator 20 and the hot air introduction duct 34 are configured to introduce hot air at predetermined temperature into the closed space defined by the partition sheet member 16.

Description

Vacuum drying device

The present invention relates to a large-sized glass substrate for producing a liquid crystal display panel, which is obtained by drying a substrate from a coating liquid by drying a substrate on which a coating film-incorporated component and a solvent coating liquid are applied in a reduced pressure state. Vacuum drying device.

In a general decompression device, the substrate is heated while depressurizing the sealed container of the working chamber by a pressure reducing pump during the vacuum drying process. Then, the solvent is evaporated in the coating liquid supplied to the substrate to be processed, and is sucked by the decompression pump by the exhaust pipe.

Since the exhaust pipe is easily affected by the atmosphere on the clean room side where the temperature is lower than that of the closed container, a portion lower than the surface temperature of the coated substrate to be heated is formed inside the exhaust pipe, and The solvent evaporated by the coated substrate is condensed inside the exhaust pipe to cause dew condensation.

In the prior art, there is a countermeasure against such condensation, in which a part of the exhaust pipe is heated by a tape heater while being dried under reduced pressure, and the supply in the exhaust pipe is adjusted. The temperature of the solvent vapor which is dried from the coating liquid is controlled by the temperature of the nitrogen gas, and the vacuum drying apparatus is configured as described above (for example, refer to Patent Document 1). In this vacuum drying apparatus, dew condensation of solvent vapor can be suppressed in the exhaust pipe at a low cost and the drying process can be quickly performed.

(Patent Document 1) Japanese Patent Laid-Open Publication No. 2003-264184

However, in the vacuum drying treatment, not only the exhaust pipe but also the portion of the sealed container which is lower in temperature than the surface temperature of the coated substrate to be heated is condensed by the solvent evaporated from the coated substrate, and condensation occurs. In order to make the condensation dry, other processing time is required, and the whole makes the drying treatment time longer and inappropriate.

In the technique of Patent Document 1, for example, it is difficult to efficiently perform heating on a movable portion such as a reinforcing rib or a lift-up pin formed on the outside of the work chamber, and therefore, even from the outside of the work chamber The movable portion such as the reinforcing rib or the substrate lifting pin is exposed to heat, and it is apparent that a part of the inside of the working chamber still has a low temperature portion which causes dew condensation.

Further, it is extremely difficult to heat the respective portions of the reinforcing rib or the substrate lifting pin formed on the outside of the work chamber by using the belt heater of Patent Document 1, and the construction or maintenance of the band heater or even the heating can be performed. Its control has to be costly.

It is an object of the present invention to provide a reduced-pressure drying apparatus which can reduce the processing time by preventing a low-temperature portion which causes dew condensation inside a working chamber or an exhaust pipe by a simple configuration and control.

In the vacuum drying apparatus of the present invention, the substrate on which the coating film-containing component and the solvent coating liquid are applied is dried under reduced pressure, and the solvent is removed from the coating liquid. The vacuum drying device has: a working room, a row Trachea, decompression means, closed space forming means and hot air supply means.

The workroom has a mounting portion on which a substrate can be placed and a heater that heats the substrate at a set temperature, and is configured to be openable and closable. Examples of the working chamber include, for example, at least one side of the upper portion of the working chamber and the lower portion of the working chamber. The exhaust pipe is connected to the workroom. The decompression means is configured to depressurize the inside of the work chamber by means of the exhaust pipe. Examples of the pressure reducing means include a pressure reducing pump such as a vacuum pump.

The closed space forming means forms a closed space at least in the working chamber around the connection portion with the exhaust pipe, the reinforcing rib, or the substrate lifting pin and the exhaust pipe. Here, the closed space does not need to be closed to a degree of airtightness, and the partition member may be a small window or a notch for providing a pipe. Moreover, all of the exhaust pipe does not have to be located in the closed space, and a part of the exhaust pipe may be located outside the closed space.

Further, it is preferable that the closed space forming means divides the space by partitioning with a partition member having flexibility. When it is considered to follow the opening and closing operation of the working chamber, the partition member is preferably a sheet material, but a flexible sheet material or a plurality of sheets which are stretchable and freely can be used.

The hot air supply means is configured to supply hot air to the space enclosed by the closed space forming means. The configuration of the hot air supply means includes, for example, a hot air generator that can generate hot air and a hot air introduction pipe that ejects hot air generated by the hot air generator in the working chamber toward the edge of the surface on which the exhaust pipe is connected.

When the hot air supply means supplies the hot air of a predetermined temperature to the closed space, it closes The interior of the joint space is substantially uniformly heated, and at the same time, hot air is ejected to a portion disposed in the closed space or the exhaust pipe in the work chamber. In particular, for a movable portion such as a reinforcing rib, a lift pin, and the like, a hot air can be ejected from a portion where the structure is complicated and it is difficult to uniformly heat, so that it is easy to uniformly heat the portions. As a result, it can prevent the low temperature portion where condensation causes.

Further, the hot air supply means is preferably such that the inner wall of the working chamber or the inside of the exhaust pipe is maintained at a temperature between the evaporation temperature at which the solvent should be removed and the dew condensation temperature. The reason is because the general dew condensation temperature is lower than the evaporation temperature.

According to the present invention, it is possible to prevent the low temperature portion which causes condensation during the inside of the work chamber or the inside of the exhaust pipe by a simple configuration and control, and the processing time can be greatly shortened.

Hereinafter, the vacuum drying apparatus 10 according to the embodiment of the present invention will be described with reference to Fig. 1 . Here, the vacuum drying apparatus 10 is used in a manufacturing process of a liquid crystal display, and is installed in a clean room. The vacuum drying apparatus 10 has a work chamber upper portion 12 and a work chamber lower portion 14 that form a sealed container. The work chamber upper portion 12 and the work chamber lower portion 14 can be opened and closed by either side of the movement. In the present embodiment, the working chamber lower portion 14 is exemplified as being movable to the working chamber upper portion 12. However, if the working chamber upper portion 12 is movable to the working chamber lower portion 14, such a configuration can be applied to the present invention.

The upper portion 12 of the working chamber is internally provided with an upper heating plate 36. The upper heating plate 36 heats the inside of the sealed container at a set temperature.

The working chamber lower portion 14 is internally provided with a substrate support pin 42 and a lower heating plate. 38. The substrate supporting pin 42 is configured to support the substrate 40 during the drying process. In the present embodiment, the substrate 40 is a glass substrate on which a coating liquid is supplied to form a film of a pigment resist. The lower heating plate 38 is configured to heat the inside of the sealed container at a set temperature. A plurality of lift pins 44 are provided at the bottom of the lower portion 14 of the work chamber. The lift pins 44 are configured to be expandable and contractible, and the base plate 40 is configured to move the base plate up and down. In the present embodiment, although 16 lift pins 44 are used, the number of lift pins 44 is not limited to this.

The lower portion 14 of the workroom is supported by the air cylinder 30 so as to be movable up and down. An opening portion that connects the exhaust pipe 32 connected to the pressure reducing pump 28 is provided at the bottom of the lower portion 14 of the working chamber. In order to correspond to the lifting operation of the lower portion 14 of the working chamber, the exhaust pipe 32 is provided with a flexible pipe at a portion extending in the vertical direction.

In the vacuum drying apparatus 10 of the present embodiment, the separator material 16, the hot air generator 20, and the hot air introduction pipe 34 are further provided. The separator material 16 is configured to cover the outer peripheral surface of the work chamber 14, the lift pins 44, the exhaust pipe 32, and other components. As shown in FIG. 2, the separator material 16 is attached to the outer peripheral surface of the lower portion 14 of the working chamber by a plurality of sheet fixing plates 162 and bolts 164. In the present embodiment, the separator material 16, the sheet fixing plate 162, and the bolt 164 correspond to the closed space forming means of the present invention.

The separator material 16 is composed of a material having a transparency of a thickness of about 150 μm. The separator material 16 is composed of a soft physical intermediate layer suitable for use as a separator material (for example, metallocene polyethylene Metallocene) And a surface layer (conductive agent-bonded polyethylene) having a charging prevention property disposed on the intermediate layer; However, the constitution of the separator material 16 is not limited thereto, and it is also applicable to a separator material formed of other materials. Further, the separator material 16 has a window hole or a notch through which the hot air introduction pipe 34 or the exhaust pipe 32 can pass.

The hot air generator 20 is configured to generate hot air at a set temperature and air volume. A temperature sensor 22 including a thermocouple capable of detecting the hot air temperature is disposed near the air outlet of the hot air generator 20. In the present embodiment, the set temperature of the hot air generator 20 is set to be lower than the set temperature of the upper heating plate 36 (for example, 68 ° C) by 5 to 6 ° C, but the temperature setting is not limited. .

The hot air introduction pipe 34 causes the hot air generated by the hot air generator 20 to be uniformly fed into the space surrounded by the separator material 16. The hot air introduction pipe 34 is provided with an air cleaner 24 for maintaining the cleanness of the hot air. In the present embodiment, the air cleaner 24 uses a HEPA (High Efficiency Particle Air) filter, but the air cleaner 24 is not limited thereto. Further, a differential pressure gauge 18 is provided in the hot air introduction pipe 34. A differential pressure gauge 18 can be used to monitor and control the flow of air. Here, the arrangement of the differential pressure gauge 18 is provided for the purpose of blocking the intrusion of polluted air.

The configuration of the hot air introduction pipe 34 will be described below using FIG. The hot air introduction pipe 34 has a hot air duct 346 and a hot air ejecting unit 342. The hot air duct 346 can be introduced into the hot air ejecting unit 342 by a plurality of paths while the hot air from the hot air generator 20 is branched. In order to correspond to the lifting operation of the lower portion 14 of the working chamber, the vertical extension of the hot air duct 346 is added Flexible piping. Further, in order to prevent the imbalance of the hot air flow in a plurality of paths, it is preferable to make the lengths of the hot air ducts of the respective paths the same.

The hot air ejecting portion 342 has a plurality of hot air ejecting holes 344. The hot air ejecting portion 342 is formed in an annular shape along the outer circumference of the lower portion 14 of the writing chamber, and is capable of ejecting hot air to the outer edge portion of the bottom surface of the working chamber lower portion 14. The reason why the hot air ejecting portion 342 is configured in this way is considered to be because the heat generation is the largest since the outer periphery of the lower portion 14 of the working chamber. Further, the hot air ejecting portion is provided below the lower portion of the working chamber in the closed space and is located further inside than the connecting portion of the exhaust pipe.

The hot air discharged from the hot air blowing portion 342 toward the working chamber lower portion 14 flows through the closed space, and is then discharged from the lower exhaust port 26. Here, although the degree of washing of the hot air is emphasized without circulating the hot air, a configuration in which the hot air is circulated may be employed. In the present embodiment, the hot air generator 20 and the hot air introduction pipe 34 correspond to the hot air supply means of the present invention.

In the above configuration, the vacuum drying apparatus 10 decompresses the closed container in the upper portion 12 of the working chamber and the lower portion 14 of the working chamber by the pressure reducing pump 28 during the vacuum drying treatment. In the present embodiment, the upper heating plate 36 is set to 68 ° C, and vacuum suction is performed in a state where the lower heating plate 38 is OFF. As a result, the solvent supplied to the coating liquid of the substrate 40 is evaporated and sucked to the decompression pump 28 side by the exhaust pipe 32.

Moreover, in the vacuum drying process, the hot air generator 20 is operated to spread the hot air into the separator material 16. When the hot air flows into the separator material 16, since the outer surfaces of the exhaust pipe 32 and the lower portion 14 of the working chamber are heated, the inner surface temperature of the lower portion 14 of the working chamber or the temperature in the exhaust pipe 32 is suppressed to 66 to 68. The range of °C. Therefore, due to the surface temperature of the substrate 40 and the inner surface temperature of the lower portion 14 of the working chamber or the temperature inside the exhaust pipe 32 There is substantially no difference between the two, so that condensation does not occur inside the work chamber lower portion 14 or the exhaust pipe 32.

Further, as shown in FIG. 4, since the separator material 16 corresponding to the lifting operation of the lower portion 14 of the working chamber is flexible, when a closed space is formed below the lower portion 14 of the working chamber, it is not correct. The lifting operation of the lower portion 14 of the working room is hindered.

Further, in the above configuration, the drying process for each of the coated substrates must be about 800 seconds with respect to the heating of the outer surface of the closed container which is not performed by the hot air generator 20, and the container is closed by the hot air generator 20, for example. When the outer surface is heated, the drying treatment time per one coated substrate can be shortened to about 600 seconds.

In the present embodiment, the working chamber lower portion 14 is configured to move the working chamber upper portion 12, but the working chamber upper portion 12 is movable to the working chamber lower portion 14, or the shutter opening and closing working chamber is used. This can also be applied to the invention of the present application. When a closed space is formed above the upper portion 12 of the work chamber, it is preferable to provide a frame member for supporting the separator material 16 above the upper portion 12 of the work chamber.

Further, in the above embodiment, the drying process of the glass substrate in the manufacturing process of the liquid crystal display has been described, but the scope of application of the present invention is not limited thereto. For example, the present invention relates to a heat-insulating and heating of a sealed container or a vacuum tube of a vacuum drying apparatus used in the field of a semiconductor device, a heat insulating and heating of a sealed container or tube of a CVD apparatus in the field of a semiconductor device, and a closed container of a sputtering apparatus in the FPD field. Insulation heating, etc. can also be applied.

The descriptions of the above embodiments are all illustrative and should be considered as not Restrictive meaning. Further, the scope of the present invention is not limited to the above embodiments, and is as indicated in the claims. The scope of the present invention is intended to cover all modifications within the meaning and scope of the invention.

10‧‧‧Decompression drying device

12‧‧‧ upper part of the working room

14‧‧‧Lower of the working room

16‧‧‧Separator material

18‧‧‧Micro differential pressure gauge

20‧‧‧Hot wind generator

22‧‧‧ Temperature Sensor

24‧‧‧Air filter

26‧‧‧Exhaust port

28‧‧‧Decompression pump

30‧‧‧ cylinder

32‧‧‧Exhaust pipe

34‧‧‧hot air inlet pipe

36‧‧‧Upper heating plate

38‧‧‧ Lower heating plate

40‧‧‧Substrate

42‧‧‧Substrate support pin

44‧‧‧lifting pin

162‧‧‧Sheet fixing plate

164‧‧‧ bolt

342‧‧‧Hot air ejector

344‧‧‧hot air venting holes

346‧‧‧Hot air duct

Fig. 1 is a schematic view showing a vacuum drying apparatus according to an embodiment of the present invention.

Fig. 2 is a view showing an example of the arrangement of the separator material.

Fig. 3 is a schematic view showing a hot air introduction pipe.

Fig. 4 is a view showing the vacuum drying apparatus at the time of substrate transfer.

10‧‧‧Decompression drying device

12‧‧‧ upper part of the working room

14‧‧‧Lower of the working room

16‧‧‧Separator material

18‧‧‧Micro differential pressure gauge

20‧‧‧Hot wind generator

22‧‧‧ Temperature Sensor

24‧‧‧Air filter

26‧‧‧Exhaust port

28‧‧‧Decompression pump

30‧‧‧ cylinder

32‧‧‧Exhaust pipe

34‧‧‧hot air inlet pipe

36‧‧‧Upper heating plate

38‧‧‧ Lower heating plate

40‧‧‧Substrate

42‧‧‧Substrate support pin

44‧‧‧lifting pin

Claims (8)

A vacuum drying apparatus which removes the solvent from the coating liquid by drying a substrate coated with a coating liquid containing a coating film component and a solvent under reduced pressure; A working chamber including an upper portion of an openable and closable working chamber and a lower portion of the working chamber, the inside of which includes: a mounting portion on which the substrate is placed; and a heater that heats the substrate at a set temperature; a pipe connected to an opening provided at a bottom portion of the lower portion of the working chamber to communicate with the inside of the working chamber; and a pressure reducing means for decompressing the inside of the working chamber via the exhaust pipe The closed space forming means is attached to the outer peripheral surface of the lower portion of the working chamber, and surrounds at least a portion of the lower portion of the working chamber with the exhaust pipe and the exhaust pipe below the lower portion of the working chamber. a closed space is formed on the outer side of the working chamber; and a hot air supply means is provided in a manner of supplying hot air of a predetermined temperature to a space closed by the closed space forming means Configuration; and the hot air supply means includes a hot air discharge portion formed with a surface of the exhaust pipe to the lower portion of the working chamber connected to the discharge of the hot air mode. A vacuum drying apparatus which removes the solvent from the coating liquid by drying a substrate coated with a coating liquid containing a coating film component and a solvent under reduced pressure; A working chamber including an upper portion of an openable and closable working chamber and a lower portion of the working chamber, the inside of which has a mounting portion on which the substrate is placed, and a set temperature a heater for heating the substrate; an exhaust pipe connected to an opening provided at a bottom portion of the lower portion of the working chamber to communicate with the inside of the working chamber; and a pressure reducing means for passing through the row The air tube is configured to decompress the inside of the working chamber; the substrate lifting pin is disposed at a bottom portion of the lower portion of the working chamber to cause the substrate to move up and down in the working chamber; and the closed space forming means is installed in the foregoing a peripheral surface of the lower portion of the working chamber, and at least a lower portion of the working chamber lower than the substrate lifting pin at the lower portion of the working chamber to form a closed space outside the working chamber; and a hot air supply means for supplying a predetermined temperature The hot air is formed in a space closed by the closing space forming means, and the hot air supply means has a hot air ejecting unit configured to eject hot air to a surface of the lower portion of the working chamber where the substrate lifting pin is provided. A vacuum drying apparatus which removes the solvent from the coating liquid by drying a substrate coated with a coating liquid containing a coating film component and a solvent under reduced pressure, and the vacuum drying apparatus configured as described above A working chamber including an upper portion of an openable and closable working chamber and a lower portion of the working chamber, the inside of which includes: a mounting portion on which the substrate is placed; and a heater that heats the substrate at a set temperature; a pipe connected to an opening provided at a bottom portion of the lower portion of the working chamber to communicate with the inside of the working chamber; and The pressure reducing means is configured to decompress the inside of the working chamber via the exhaust pipe; the reinforcing rib is provided at a bottom portion of the lower portion of the working chamber; and the closed space forming means is attached to the lower portion of the working chamber. a peripheral surface, and at least a reinforcing rib at a lower portion of the working chamber below the lower portion of the working chamber to form a closed space on an outer side of the working chamber; and a hot air supply means for supplying a hot air of a predetermined temperature to the closed portion The hot air supply means includes a hot air ejecting unit configured to eject hot air to a surface of the lower portion of the working chamber where the reinforcing rib is provided. The vacuum drying apparatus according to any one of claims 1 to 3, wherein the lower portion of the working chamber is configured to be movable relative to an upper portion of the working chamber, and the closed space forming means is provided with flexibility Separation member. The vacuum drying apparatus of claim 4, wherein the partition member is a transparent member. The vacuum drying apparatus according to any one of claims 1 to 3, wherein the hot air blowing portion is provided below the lower portion of the working chamber in the closed space and is located inside the connecting portion of the exhaust pipe. The vacuum drying apparatus according to claim 4, wherein the hot air blowing portion is provided below the lower portion of the working chamber in the closed space and is located inside the connecting portion of the exhaust pipe. The vacuum drying apparatus according to claim 5, wherein the hot air blowing portion is provided below the lower portion of the working chamber in the closed space and is located inside the connecting portion of the exhaust pipe.