JP2006071185A - Vacuum dryer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum dryer capable of forming a film of uniform thickness on a base surface. <P>SOLUTION: A chamber 10 storing a base (plate P) and air-tightly closeable, is composed of a loading space 12 and a vertically-movable cover body 14. An exhaust pipe 24 is mounted on an upper part of the cover body 14 to reduce a pressure in the chamber 10. A plurality of exhaust ports 16 are formed on the upper part of the cover body 14, and opening diameters of valves 54 respectively mounted on the exhaust ports 16 are controlled by an opening diameter control part 52 on the basis of a control signal from a valve control part 50. The opening diameters of the valves 54 are respectively controlled to gradually decrease exhaust velocities from a central part of the chamber 10 toward an outer peripheral part with respect to the positions of the exhaust ports, thus a drying velocity of solution applied to the plate P can be uniformly kept. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a reduced-pressure drying apparatus that performs a reduced-pressure drying process on a substrate whose surface is coated with a predetermined solution or the like.

  Conventionally, in a semiconductor element manufacturing process or the like, after a resist solution or the like is applied to the surface of a substrate, a solvent component contained in the resist solution is dried to form a predetermined film (for example, a resist film). Here, when the drying process is performed, it is necessary to keep the thickness of the film to be formed uniform. Therefore, a predetermined chamber is provided, and the pressure is reduced while exhausting the inside of the chamber. A resist film having a uniform thickness was formed by drying under reduced pressure to flatten the solution.

  In order to form a resist film having a uniform thickness, there is a substrate processing apparatus that forms a uniform airflow using a rectifying plate (see Patent Document 1). The substrate processing apparatus supports the rectifying plate so as to be parallel to the substrate mounting table, and keeps the velocity of the airflow flowing between the rectifying plate and the substrate uniform on the substrate surface. A resist film having a uniform thickness is formed.

JP 2002-313709 A

  By the way, the solution is usually applied in a uniform state on the substrate. However, since the drying speed of the solution is different between the central portion and the outer peripheral portion on the substrate, the solution is applied uniformly to the substrate. There is a problem that the formed film thickness becomes non-uniform. That is, when the uniform airflow is formed on the substrate surface using the rectifying plate as in the substrate processing apparatus described in Patent Document 1 described above, the difference in drying speed between the central portion and the outer peripheral portion on the substrate. Therefore, the solvent concentration of the solution applied on the substrate is different, and the thickness of the formed film is not uniform.

  An object of the present invention is to provide a substrate having a surface coated with a predetermined solution or the like, and the reduced-pressure drying capable of forming a film having a uniform thickness by making the drying speed of the solution on the substrate surface the same. Is to provide a device.

  The reduced-pressure drying apparatus according to the present invention exhausts the atmosphere in the processing chamber from the chamber through a chamber forming an airtight processing chamber, a plurality of exhaust ports formed in an upper portion of the chamber, and the exhaust port. And an exhaust portion for decompressing the processing chamber, and an exhaust speed at which the atmosphere in the processing chamber is exhausted from the chamber through the exhaust port by the exhaust portion is provided at an outer peripheral portion of the chamber. The exhaust port provided in the central part is faster than the exhaust port.

  According to this reduced pressure drying apparatus, the exhaust speed provided at the outer peripheral part of the upper part of the chamber corresponding to the outer peripheral part of the substrate, which is faster than the central part of the substrate, has the exhaust speed at the central part of the upper part of the chamber. The exhaust speed provided at the central part of the upper part of the chamber corresponding to the central part on the substrate, which is slower than the provided exhaust port and slower than the peripheral part on the substrate, is the outer peripheral part of the upper part of the chamber. It is faster than the exhaust port provided in the. Therefore, for example, considering the difference in the drying rate of the solution on the substrate, even when the solution is uniformly applied on the substrate without changing the application amount of the solution between the central portion and the outer peripheral portion, A film having a uniform thickness can be formed by maintaining the same drying rate at the central portion and the outer peripheral portion on the substrate.

  Further, the reduced-pressure drying apparatus according to the present invention maintains the state in which the exhaust port provided in the central portion exhausts at a higher speed than the exhaust port provided in the outer peripheral portion of the chamber, An exhaust speed adjusting unit that adjusts the exhaust speed for each exhaust port is further provided.

  According to this vacuum drying apparatus, the exhaust speed at the exhaust port provided in the central portion of the upper portion of the chamber is maintained at a higher speed than that of the exhaust port provided in the outer peripheral portion of the upper portion of the chamber. The exhaust speed is adjusted. Therefore, depending on the type of coating film formed on the substrate, for example, the difference in the exhaust speed between the exhaust port provided in the central portion and the exhaust port provided in the outer peripheral portion is increased or decreased. Thus, a film having a uniform thickness can be formed with high accuracy.

  In the vacuum drying apparatus according to the present invention, the exhaust speed adjusting unit includes a valve provided at each of the exhaust ports, and an opening diameter control unit that controls an opening diameter of the valve. .

  According to this vacuum drying apparatus, the opening speed of the valve provided for each exhaust port is adjusted by the opening diameter control unit to adjust the exhaust speed. Therefore, the drying speed can be adjusted according to the type and concentration of the solution applied on the substrate, and a film having a uniform thickness can be formed reliably.

  Hereinafter, a vacuum drying apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a vacuum drying apparatus according to an embodiment. The vacuum drying apparatus 2 includes a chamber 10 that accommodates the plate P and forms a processing chamber that can be hermetically closed. The chamber 10 includes a plate P having a thickness, a rectangular mounting table 12 having a thickness, and a lid 14 positioned above the mounting table 12 and having a rectangular opening on the lower surface. A plurality of exhaust ports 16 having openings of a predetermined size are formed in the upper part of the lid body 14 of the chamber 10.

  The lid body 14 is provided with an elevating mechanism 18 that moves the lid body 14 up and down. The elevating mechanism 18 includes, for example, a drive unit 20 that raises and lowers the lid body 14 with a motor, and a control unit 22 that controls the drive unit 20. As a result, the lid body 14 can be moved in the vertical direction, and the lid body 14 is lowered to form a processing chamber integrally with the mounting table 12.

  An exhaust pipe 24 is provided on the upper surface of the lid body 14 as an exhaust section for exhausting the atmosphere in the processing chamber. The exhaust pipe 24 is communicated with a suction pump 26 that sucks the atmosphere in the processing chamber at a predetermined pressure, and the suction force of the suction pump 26 is controlled by a pump control unit 28. With this configuration, the suction pump 26 is operated, and the atmosphere in the chamber 10 can be exhausted and sucked from the exhaust pipe 24 to reduce the pressure in the chamber 10. Further, an O-ring 30 is provided on the lower end surface of the lid body 14 to ensure the airtightness of the processing chamber.

  A supply unit 32 that supplies gas, for example, nitrogen gas, to the processing chamber is connected to the exhaust pipe 24 through the exhaust pipe 24. As a result, the gas can be supplied into the processing chamber after the reduced pressure drying process to recover the reduced pressure state, or the atmosphere in the processing chamber can be purged.

  Exhaust of the atmosphere in the processing chamber by the exhaust pipe 24 is performed through a plurality of exhaust ports 16 provided in the upper part of the lid body 14. Here, as shown in FIG. 1, each of the exhaust pipes 24 connected to the plurality of exhaust ports 16 is provided with a valve 54, and each valve 54 has a control signal from the valve control unit 50. Is connected to an opening diameter controller 52 for controlling the opening diameter of the valve. That is, the opening diameter of the valve 54 provided in each of the exhaust ports 16 provided in the upper part of the lid body 14 is controlled by the opening diameter control unit 52 based on the control signal from the valve control unit 50, and each exhaust port 16 is controlled. The exhaust speed at the port 16 is adjusted. For example, as shown in FIG. 2, when a plurality of exhaust ports 16 are formed in the lid body 14, the exhaust speed increases as the position where the exhaust ports are formed changes from the central portion of the chamber 10 to the outer peripheral portion. The opening diameter of the valve 54 is controlled so as to be delayed. In other words, the opening speed of the valve 54 is controlled and the exhaust speed is adjusted so that the exhaust speed is the fastest in the central part where the dry speed is the slowest and the exhaust speed gradually decreases as it goes to the outer peripheral part where the dry speed is fast. Therefore, the exhaust speed decreases as it goes from the central part to the outer peripheral part, and the drying speed of the solution on the plate P can be kept uniform.

  The atmosphere on the surface of the plate P during exhaust from the exhaust pipe 24 is adjusted by controlling the opening diameter of the valve 54 provided in each exhaust port 16 provided in the upper part of the lid 14 to adjust the exhaust speed. Is sucked through each exhaust port 16 provided in the upper part of the lid body 14, and an air flow toward the exhaust pipe 24 is formed. In other words, the opening diameter of the valve 54 is controlled so that the velocity of the airflow flowing on the surface of the plate P decreases as the position of the exhaust port 16 changes from the central portion to the outer peripheral portion at the upper portion of the lid body 14. In the central part where the drying speed is low, the airflow speed is high, and in the outer peripheral part where the drying speed is high, the airflow speed is low, and the drying speed on the plate P is kept the same.

  The mounting table 12 is provided with a temperature adjusting member that adjusts the mounting table 12 to a predetermined temperature, for example, a Peltier element 34. The temperature of the Peltier element 34 is controlled by a temperature control unit 36 that controls the power source of the Peltier element 34. Thereby, the mounting table 12 can be adjusted to a predetermined temperature, and the plate P on the mounting table 12 can be maintained at a predetermined temperature.

  On the mounting table 12, a proximity pin 38 is provided at a position corresponding to the outer edge of the plate P on the mounting table 12, and the plate P is mounted on the proximity pin 38. Thereby, since heat exchange with the mounting table 12 is performed by radiant heat, the uniformity of the in-plane temperature of the plate P can be ensured.

  Below the mounting table 12, a plurality of elevating pins 40 that are means for supporting the lower surface of the plate P and elevating it are provided. The elevating pin 40 is provided upright on the flange 42. The elevating pin 40 is movable in a through hole 44 provided near the center of the mounting table 12. The raising / lowering pin 40 is connected to the raising / lowering drive part 46 provided with the cylinder etc. which move the flange 42 to an up-down direction. As a result, the elevating pins 40 can move up and down in the through holes 44 and protrude onto the mounting table 12.

  The elevating pin 40 between the flange 42 and the through hole 44 is covered with a bellows 48 that can be expanded and contracted. As a result, an external atmosphere is prevented from flowing into the processing chamber through the through hole 44, and airtightness in the processing chamber is ensured.

  Next, the drying process in the reduced pressure drying apparatus 2 will be described. In the following, a case where the reduced pressure drying apparatus 2 is incorporated in the liquid crystal display device manufacturing line 100 for manufacturing a liquid crystal display device will be described as an example.

  FIG. 3 is a diagram showing an example of the configuration of a liquid crystal display device production line including the reduced pressure drying apparatus 2 according to the embodiment of the present invention. As shown in FIG. 3, the liquid crystal display device production line 100 includes a cleaning device 112, a discharge device (droplet discharge device) 114, a vacuum drying device 2, a baking device 116, a rubbing device 118, and each device used in each process. Belt conveyor BC, a driving device 122 for driving the belt conveyor BC, and a control device 120 for controlling the entire liquid crystal display device production line 100. Further, the cleaning device 112, the discharge device 114, the reduced pressure drying device 2, the baking device 116, and the rubbing device 118 are arranged in a line at predetermined intervals along the belt conveyor BC.

  The control device 120 is connected to the cleaning device 112, the discharge device 114, the vacuum drying device 2, the baking device 116, the rubbing device 118, and the driving device 122. The driving device 122 drives the belt conveyor BC based on a control signal from the control device 120, and the substrate of the liquid crystal display device (hereinafter simply referred to as “substrate”) is the cleaning device 112, the discharge device 114, and the vacuum drying device. 2. It conveys to the baking apparatus 116 and the rubbing apparatus 118. The cleaning device 112 performs processing for cleaning the substrate, and the ejection device 114 performs processing for applying an alignment film material on the substrate, that is, processing for discharging droplets containing the alignment film material on the substrate. In the vacuum drying apparatus 2, a process of temporarily drying the alignment film material is performed. Further, the baking apparatus 116 performs a process for baking the temporarily dried alignment film material, and the rubbing apparatus 118 performs a rubbing process for the alignment film.

  Next, with reference to the flowchart of FIG. 4, the manufacturing process of the liquid crystal display device in the liquid crystal display device manufacturing line using the reduced pressure drying apparatus according to the embodiment will be described.

  First, the substrate (plate P) on which the alignment film is formed is washed (step S10). For example, the plate P on which the segment electrodes are formed is conveyed to the cleaning device 112 by the belt conveyor BC. After the plate P conveyed by the belt conveyor BC is taken into the cleaning device 112 and washed with an alkaline detergent, pure water or the like, the plate P is washed at a predetermined temperature and time, for example, 80 to 90 ° C. A process of drying for 10 minutes is performed. The plate P that has been cleaned and dried is conveyed to the discharge device 114 by the belt conveyor BC.

  Next, an alignment film material is applied on the plate P washed in step S10 (step S11). That is, first, the plate P conveyed to the discharge device 114 by the belt conveyor BC is taken into the discharge device 114. In the discharge device 114, the alignment film material accommodated in the tank is discharged through a nozzle, and the alignment film material is applied onto the plate P. Next, the plate P is left in the discharge device 114 in a horizontal state, for example, for 1 minute, and leveling is performed. Then, it moves to the belt conveyor BC from the discharge apparatus 114, and is conveyed to the reduced pressure drying apparatus 2 by the belt conveyor BC.

  Next, a process of temporarily drying the alignment film material applied to the plate P is performed (step S12). That is, the plate P conveyed to the vacuum drying apparatus 2 by the belt conveyor BC is placed on the mounting table 12 and taken into the vacuum drying apparatus 2.

  Here, the drying process in the reduced pressure drying apparatus 2 will be described. First, before the plate P is conveyed to the reduced pressure drying apparatus 2, the mounting table 12 is maintained at a predetermined temperature, for example, room temperature by the temperature control unit 36 and the Peltier element 34. In the vacuum drying apparatus 2, drying conditions are set in advance so that the variation in the thickness of the alignment film that has been temporarily dried is within a range of ± 5%. The drying conditions include an exhaust speed through each exhaust port 16 by controlling the opening diameter of each valve 54 by the opening diameter control unit 52 based on a control signal from the valve control unit 50, and the like. For example, it is set in advance by performing a drying condition setting test for drying the plate P on which the alignment film material is applied as a test. The exhaust speed can be arbitrarily adjusted by controlling the opening diameter of the valve 54 by the opening diameter control unit 52, but the exhaust speed is always the fastest in the central part of the chamber 10, and from the central part to the outer peripheral part. It is adjusted while maintaining a state where it gradually becomes slower as it goes.

  Next, the plate P is transported from the discharge device 114 via the belt conveyor BC and moved to above the mounting table 12. At this time, the lid 14 is raised by the elevating mechanism 18 as shown in FIG. 5, and the plate P is moved to above the mounting table 12. The plate P that has been moved to the upper side of the mounting table 12 is transferred to the lifting pins 40 that have been lifted and waited in advance on the mounting table 12. Next, the elevating pin 40 is lowered by the elevating drive unit 46, and the plate P is placed on the proximity pin 38 on the mounting table 12. Next, the lid body 14 is lowered, and the lower end portion of the lid body 14 is brought into close contact with the mounting table 12 to form an airtight processing chamber.

  Next, the suction pump 26 is operated, and the atmosphere in the processing chamber starts to be sucked at a predetermined pressure through the exhaust pipe 24. Along with this, an air flow is formed in the processing chamber. The air flow forms an air flow toward each exhaust port 16 and flows to the exhaust pipe 24 via each exhaust port 16. Each exhaust port 16 has its opening diameter controlled so that the exhaust speed gradually decreases from the central portion toward the outer peripheral portion, so that drying is performed while keeping the drying speed on the plate P uniform. . That is, the opening diameter of the valve 54 is controlled so that a high-speed airflow is formed at the center of the plate P having a low drying speed and a low-speed airflow is formed at the outer periphery of the plate P having a high drying speed. Therefore, the drying speed in the whole plate P is kept uniform.

  Then, after drying for a predetermined time, the suction pump 26 is stopped, and the decompression in the processing chamber is stopped. Next, nitrogen gas is supplied from the supply unit 32 through the exhaust pipe 24 into the processing chamber, and the pressure in the processing chamber is recovered. Then, when the pressure in the processing chamber is recovered to atmospheric pressure, the supply of nitrogen gas is stopped.

  Next, the lid 14 is raised by the elevating mechanism 18, and the processing chamber formed by the chamber 10 is opened. Then, in the same manner as when carrying in, the plate P is lifted by the lifting pins 40 (see FIG. 5) and delivered to the belt conveyor BC. The plate P delivered to the belt conveyor BC is unloaded from the reduced pressure drying device 2 and conveyed to the baking device 116.

  Next, a process of baking the alignment film material that has been temporarily dried is performed (step S13). That is, the plate P conveyed to the baking apparatus 116 by the belt conveyor BC is taken into the baking apparatus 116, and is baked at 180 to 250 ° C., for example. In addition, the plate P on which the alignment film is formed by baking is transferred to the belt conveyor BC and is conveyed to the rubbing device 118 by the belt conveyor BC.

  Next, a process of rubbing the alignment film formed on the plate P is performed (step S14). That is, the plate P conveyed to the rubbing device 118 by the belt conveyor BC is taken into the rubbing device 118, and the rubbing process is performed by rubbing the alignment film formed on the plate P using a cloth, for example. After the rubbing process is performed on the alignment film, the plate P is transferred to the belt conveyor BC and is stored in a substrate storage cassette (not shown) by the belt conveyor BC. Further, the plate P accommodated in a substrate accommodation cassette or the like (not shown) is bonded to another plate on which a color filter, a black matrix, an overcoat film, a common electrode and an alignment film are formed in an assembly apparatus (not shown). And a liquid crystal display device is manufactured by inject | pouring a liquid crystal between the bonded plates.

  In the vacuum drying apparatus according to the embodiment of the present invention, a valve is provided in each of the plurality of exhaust ports formed in the upper portion of the lid, and the exhaust rate is increased as the position of the exhaust port is changed from the center to the outer periphery. The opening diameter of each valve is controlled so as to gradually slow down. That is, when a predetermined solution is uniformly applied on the substrate, the drying speed differs between the central portion and the outer peripheral portion under the same conditions, and the drying speed of the outer peripheral portion is faster than the drying speed of the central portion. It has become. Therefore, by controlling the opening diameter of the valve so that the exhaust speed gradually decreases from the central part to the outer peripheral part, the drying speed of the solvent on the substrate can be kept uniform, and the thickness of the film to be formed The thickness can be made uniform.

  In addition, the reduced-pressure drying apparatus according to the embodiment of the present invention can adjust the exhaust speed by controlling the opening diameter of the valve provided at the exhaust port using the opening diameter control unit. That is, the exhaust speed can be adjusted so that the thickness of the film formed by the applied solution is uniform in consideration of the type of solution applied to the substrate, the solvent concentration, the viscosity, and the like. Therefore, by controlling the opening diameter of the valve provided at the exhaust port, the drying speed can be adjusted so that a film having a uniform thickness can be reliably formed.

  In the vacuum drying apparatus according to the above-described embodiment, the case where a liquid crystal display device is manufactured has been described as an example. However, the liquid crystal display device may be used when manufacturing other devices. For example, you may make it use in manufacturing processes, such as a color filter, overcoat, organic EL, and a semiconductor element.

The block diagram of the reduced pressure drying apparatus which concerns on embodiment. The figure for demonstrating the exhaust port of the reduced pressure drying apparatus which concerns on embodiment. The figure which shows an example of the liquid crystal display device manufacturing line which concerns on embodiment. 6 is a flowchart illustrating a manufacturing process of a liquid crystal display device according to an embodiment. The figure for demonstrating operation | movement of the vacuum drying apparatus which concerns on embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Decompression drying apparatus, 10 ... Chamber, 12 ... Mounting stand, 14 ... Cover body, 16 ... Exhaust port, 50 ... Valve control part, 52 ... Opening diameter control part, 54 ... Valve, 100 ... Liquid crystal display device production line, DESCRIPTION OF SYMBOLS 112 ... Cleaning apparatus, 114 ... Discharge apparatus, 116 ... Baking apparatus, 118 ... Rubbing apparatus, 120 ... Control apparatus, 122 ... Drive apparatus, P ... Plate.

Claims (3)

A chamber forming an airtight process chamber;
A plurality of exhaust ports formed in an upper portion of the chamber;
An exhaust unit that exhausts the atmosphere in the processing chamber from the chamber through the exhaust port and depressurizes the processing chamber;
The exhaust speed at the time of exhausting the atmosphere in the processing chamber from the chamber through the exhaust port by the exhaust unit is provided in the central portion as compared with the exhaust port provided in the outer peripheral portion of the chamber. A reduced-pressure drying apparatus characterized in that the exhaust port is faster.   Exhaust speed that adjusts the exhaust speed for each exhaust port while maintaining the exhaust port provided in the central portion exhausting at a higher speed than the exhaust port provided in the outer peripheral portion of the chamber The reduced-pressure drying apparatus according to claim 1, further comprising an adjustment unit. The exhaust speed adjusting unit is
A valve provided in each of the exhaust ports;
The reduced-pressure drying apparatus according to claim 2, further comprising an opening diameter control unit that controls an opening diameter of the valve.

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