TWI837341B - Reduced pressure drying device - Google Patents

Abstract

[Topic] Making the drying time of a solution on a substrate more uniform within the surface of the substrate. [Solution] A decompression drying device dries a solution applied on a substrate under decompression, wherein the decompression drying device is characterized in that it comprises: a solvent collection portion temporarily collecting the solvent in the solution vaporized from the substrate, the solvent collection portion being arranged to face the substrate and divided into a plurality of regions, openings being formed in the plurality of regions, and the heat capacity per unit area of each of the plurality of regions being different according to the portion of the substrate facing the region.

Description

Pressure reduction drying device

The present disclosure relates to a pressure reduction drying device.

Patent document 1 discloses a decompression drying device for drying a solution on a substrate contained in a chamber under a decompression state. In the decompression drying device, a solvent collection net is provided. The solvent collection net is composed of a mesh plate and is used to temporarily collect the solvent in the solution vaporized from the substrate, and is provided in the chamber to face the substrate. In the decompression drying device disclosed in Patent document 1, the solvent collection net is provided so that the drying time becomes uniform within the surface of the substrate. [Prior technical document] [Patent document]

[Patent Document 1] Japanese Patent Application Publication No. 2018-59597

[Problems to be solved by the present invention]

The technology disclosed herein is to make the drying time of the solution on the substrate more uniform within the surface of the substrate. [Method for solving the problem]

One aspect of the present disclosure is a decompression drying device for drying a solution applied on a substrate under decompression, characterized in that it has: a solvent collection portion for temporarily collecting the solvent in the solution vaporized from the substrate, the solvent collection portion being arranged to face the substrate and divided into a plurality of regions, openings being formed in the plurality of regions, and being formed so that the heat capacity per unit area of each of the plurality of regions is different according to the portion of the substrate facing the region. [Effect of the invention]

According to the present invention, the drying time of the solution on the substrate can be made more uniform within the surface of the substrate.

In the past, organic light emitting diodes (OLEDs) that utilize organic EL (Electroluminescence) have been known. Organic EL displays that use these organic light emitting diodes have advantages such as being thin, light, and low in power consumption, as well as being excellent in response speed, viewing angle, and contrast. Therefore, they have attracted much attention as next-generation flat panel displays (FPDs) in recent years.

An organic light-emitting diode has a structure in which an organic EL layer is sandwiched between an anode and a cathode on a substrate. The organic EL layer is formed by, for example, stacking a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer in order from the anode side. When forming each layer of these organic EL layers (especially the hole injection layer, the hole transport layer, and the light-emitting layer), for example, the following method is used: droplets of organic material are ejected into the bank corresponding to the pixels of each color discretely arranged on the substrate by inkjet printing, thereby coating a film of the organic material of the pixel inside the bank.

The organic material ejected onto the substrate by inkjet printing contains a large amount of solvent. Therefore, a decompression drying process is performed to remove the solvent, in which the solvent on the substrate is dried under reduced pressure.

As a decompression drying device for performing decompression drying treatment, Patent Document 1 discloses a device having: a chamber that is constructed to be airtight and decompressed by an exhaust device; and a solvent collection net that is arranged in the chamber to face the substrate and collect the solvent volatilized from the organic material film on the substrate. As in Patent Document 1, by setting the solvent collection net, the drying time of the solution on the substrate can be made roughly uniform within the surface of the substrate. However, as described below, the uniformity of the drying time of the solution on the substrate within the surface still has room for improvement.

For example, when a single substrate is used as a panel for an FPD, as shown in FIG1 , an organic material M is applied to substantially the entire surface of the substrate W except for the peripheral portion. When the coating is performed in this manner, even if a solvent collecting net is provided as in Patent Document 1, the drying time of the solvent in the center portion WC of the substrate may be longer than that in the corner portion WP of the substrate.

In addition, there is also a case where a single substrate is divided and used as a plurality of panels (e.g., four panels) for FPD. In this case, as shown in FIG. 2 , an organic material M is applied to substantially the entire surface of the panel P except for the peripheral portion thereof formed by dividing the substrate W. When applying in this manner, even if a solvent collecting net is provided as in Patent Document 1, the drying time of the solvent in the center PC of the panel may be longer than that in the corner PP of the panel.

As described above, when there is a difference in the drying time of the solvent, the coating film formed at the substrate corner WP or the panel corner PP, which is dried first, is dissolved by the solvent vaporized at the substrate center WC or the panel center PC, which is not dried yet. In addition, as described above, as a reason for the difference in the drying time of the solvent, the following can be cited: Since the concentration of the solvent in the surrounding atmosphere is low at the boundary between the coated area and the non-coated area of the organic material M, the solvent is easily volatilized.

Therefore, the technology disclosed in the present invention makes the drying time of the solution on the substrate more uniform within the surface of the substrate.

In the following, the reduced pressure drying device of this embodiment is described with reference to the drawings. In addition, in this specification and the drawings, the elements having substantially the same functional structure are given the same symbols and repeated description is omitted.

(First embodiment) Figures 3 and 4 are diagrams showing the schematic structure of the pressure-reducing drying device of the first embodiment, with Figure 3 being a cross-sectional view and Figure 4 being a top view. In Figure 3, the structure for supporting the solvent collection net described later is omitted, and in Figure 4, the top plate described later is omitted. Figures 5 and 6 are diagrams for explaining the installation structure of the solvent collection net, with Figure 5 being a partial side view of the inside of the pressure-reducing drying device and Figure 6 being a bottom view of the solvent collection net and its surroundings in the pressure-reducing drying device.

The reduced pressure drying device 1 of FIG3 dries the solution applied on the substrate by, for example, inkjet method under reduced pressure. The substrate to be processed by the reduced pressure drying device 1 is, for example, a glass substrate for an organic EL display, and is used as a panel for an FPD as a whole, similar to the one shown in FIG1 . In addition, the substrate to be processed is a large substrate, and its width is, for example, 215 mm.

The solution applied to the substrate to be treated is composed of a solute and a solvent. The component to be treated by the reduced pressure drying treatment is mainly the solvent. Most of the organic compounds contained in the solvent are high boiling point compounds, such as 1,3-dimethyl-2-imidazolidinone (boiling point 220°C, melting point 8°C), 4-tert-Butylanisole (boiling point 222°C, melting point 18°C), and Trans-Anethole (boiling point 235°C, melting point 20°C). 、1,2-Dimethoxybenzene (1,2-Dimethoxybenzene, boiling point 206.7℃, melting point 22.5℃), 2-Methoxybiphenyl (2-Methoxybiphenyl, boiling point 274℃, melting point 28℃), Phenyl Ether (Phenyl Ether, boiling point 258.3℃, melting point 28℃), 2-Ethoxynaphthalene (2-Ethoxynaphthalene, boiling point 282℃, melting point 35℃), Benzyl Phenyl Ether (Benzyl Phenyl ether, boiling point 288℃, melting point 39℃), 2,6-dimethoxytoluene (boiling point 222℃, melting point 39℃), 2-propoxynaphthalene (boiling point 305℃, melting point 40℃), 1,2,3-trimethoxybenzene (boiling point 235℃, melting point 45℃), cyclohexylbenzene (boiling point 237.5℃, melting point 5℃), dodecylbenzene (boiling point 288℃, melting point -7℃), 1,2,3,4-tetramethylbenzene (boiling point 203℃, melting point 76℃), etc. These high boiling point organic compounds may be mixed in solution in combination of two or more.

The reduced pressure drying device 1 includes a chamber 10 and a mounting table 20 , and is connected to an exhaust device 30 .

The chamber 10 is a depressurized processing container, and is formed of a metal material such as stainless steel. The chamber 10 includes a rectangular cylindrical body 11, a top plate 12 mounted on the upper side of the body 11, and a bottom plate 13 mounted on the lower side of the body 11.

The main body 11 is provided with a loading and unloading port (not shown) on its side for loading and unloading the substrate W into and out of the chamber 10. The top plate 12 blocks the opening on the upper side of the main body 11 and supports the solvent collection net 40 described later.

The top plate 13 blocks the opening on the lower side of the body 11. A mounting table 20 is provided at the center of the upper side of the bottom plate 13. An exhaust slit 13a is provided on the bottom plate 13 so as to surround the outer periphery of the mounting table 20. An exhaust device 30 is connected to the exhaust slit 13a via an exhaust pipe 31. The chamber 10 of the decompression drying device 1 can be depressurized via the exhaust slit 13a.

The stage 20 is used to place the substrate W. A lifting pin (not shown) is provided on the stage 20 so as to penetrate the stage 20. The lifting pin is used to transfer the substrate W to and from a substrate transfer device (not shown) that inserts the substrate W from the outside of the chamber 10 into the chamber 10. The lifting pin is configured to be freely movable up and down by a lifting mechanism (not shown).

In addition, the exhaust device 30 is composed of a vacuum pump, specifically, a turbomolecular pump and a dry pump are connected in series from the upstream side. An automatic pressure control valve (APC (Adaptive Pressure Control) valve) 32 is provided between the exhaust port slit 13a in the exhaust pipe 31 and the exhaust device 30. In the decompression drying device 1, the opening and closing degree of the APC valve 32 is adjusted while the vacuum pump of the exhaust device 30 is activated, thereby controlling the vacuum degree in the chamber 10 during decompression exhaust. In addition, in order to control the above vacuum degree by the APC valve 32, a pressure gauge (not shown) for measuring the pressure in the chamber 10 is provided in the decompression drying device 1. The measurement result of the above pressure gauge is input to the APC valve 32 as an electrical signal.

Furthermore, the reduced pressure drying device 1 has a control unit (not shown). The control unit is, for example, a computer having a CPU or a memory, and has a program storage unit (not shown). The program storage unit stores a program for controlling the reduced pressure drying process in the reduced pressure drying device 1. In addition, the above program may be recorded in a computer-readable storage medium, and may be installed in the above control unit from the storage medium. Part or all of the program may also be implemented by dedicated hardware (circuit board).

Furthermore, the reduced pressure drying device 1 is provided with a solvent collecting net 40 as a solvent collecting portion, which temporarily collects the solvent in the solution vaporized from the substrate W placed on the mounting table 20. Specifically, the solvent collecting net 40 collects the solvent vaporized from the solution applied on the substrate W by the inkjet method. By arranging the solvent collecting net 40 in the chamber 10, the solvent concentration in the atmosphere in the chamber 10 can be adjusted.

The solvent collecting net 40 is supported by a structure on the upper part of the solvent collecting net 40 and is located between the top plate 12, which is the structure closest to the solvent collecting net 40, and the substrate W. The solvent collecting net 40 is supported by the top plate 12 in a manner facing the substrate W, that is, in a manner substantially parallel to the substrate W. In addition, the solvent collecting net 40 is supported at a distance of, for example, 75 mm from the substrate W.

The support of the solvent collecting net 40 by the top plate 12 is performed through the frame 50 and the leg 51 as shown in FIG5 . For example, the solvent collecting net 40 is fixed to the square cylindrical frame 50 by welding, and the ear 50a provided on the outside of the frame 50 is fixed to the leg 51 extending downward from the top plate 12 by screw holes, thereby supporting the solvent collecting net 40 on the top plate 12. In addition, the frame 50 or the leg 51 is made of a metal material such as stainless steel. In addition, the frame 50 or the leg 51 is sandwiched between the substrate W and the solvent collecting net 40 and is located on the opposite side. Therefore, when viewed from the substrate W side, since the solvent collecting net 40 is not covered by the frame 50 or the leg 51 , the frame 50 or the leg 51 will not hinder the flow of the vaporized solvent from the substrate W to the solvent collecting net 40 .

Next, referring to Fig. 6, details about the shape of the solvent collecting net 40 are described using Fig. 7 and Fig. 8. Fig. 7 is a partially enlarged plan view of the central area of the solvent collecting net 40, and Fig. 8 is a partially enlarged plan view of the peripheral area of the solvent collecting net 40.

The solvent collection net 40 is divided into a plurality of regions, and openings are formed in the plurality of regions. For example, the solvent collection net 40 is divided into a central region R1 and a peripheral region R2 as shown in FIG6 , and as shown in FIG7 and FIG8 , an opening 41 having a regular hexagonal shape in a top view is formed in the central region R1, and an opening 42 is formed in the peripheral region R2. In addition, the openings 41 and 42 are, for example, through holes that penetrate the solvent collection net 40 in the thickness direction of the solvent collection net 40.

Furthermore, the solvent collecting net 40 is formed so that the heat capacity per unit area in the top view of each of the plurality of regions is different according to the portion of the substrate W facing the region. In this embodiment, the opening ratios of the central region R1 facing the substrate center WC and the peripheral region R2 including the region facing the substrate corner WP are different in the solvent collecting net 40, whereby the heat capacity per unit area in the top view is different in the central region R1 and the peripheral region R2. More specifically, the solvent collecting net 40 is formed so that the opening ratio of the central region R1 is greater than the opening ratio of the peripheral region R2, and the heat capacity per unit area in the top view of the central region R1 is smaller than the same heat capacity of the peripheral region R2.

For example, the openings 41 of the central region R1 and the openings 42 of the peripheral region R2 are both regularly formed in a grid shape when viewed from above, and the distances between the openings 41 and 42 are equal. However, when viewed from above, the inner diameter of the opening 41 is larger than the inner diameter of the opening 42. In other words, when viewed from above, the width of the partition wall 41a between adjacent openings 41 is smaller than the width of the partition wall 42a between adjacent openings 42. Due to such a difference in shape, the solvent capture net 40 has a larger opening rate in the central region R1 than in the peripheral region R2. The opening ratio refers to the ratio of the area of the opening 41 or the opening 42 of the solvent collection net 40 in a plan view to the unit area of the solvent collection net 40. The opening ratio in the central region R1 and the opening ratio in the peripheral region R2 are set in the range of 60% to 80%, for example.

The solvent collecting net 40 is composed of a mesh plate having the openings 41 and 42 as described above. The mesh plate refers to a plate-like member in which the openings extending in the thickness direction are regularly formed in a lattice shape when viewed from above. The solvent collecting net 40 is composed of a material having good thermal conductivity such as stainless steel or a metal material such as aluminum, copper, or gold. The openings 41 and 42 of the solvent collecting net 40 are formed, for example, by laser processing.

In addition, the solvent collection net 40 is thin, and its thickness is, for example, 0.05 mm to 0.2 mm. Moreover, the horizontal dimension of the solvent collection net 40 is substantially the same as the horizontal dimension of the substrate W. However, in order to increase the adsorption amount of the vaporized solvent, the horizontal dimension of the solvent collection net 40 may also be larger than the horizontal dimension of the substrate W.

In addition, since the solvent collection net 40 has an opening rate as large as 60% to 80% and a thickness as thin as 0.05 to 0.2 mm even in any region where the opening rate varies among regions as described above, the heat capacity per unit area in a top view is small.

Next, the decompression drying process using the decompression drying device 1 is described. In the decompression drying process using the decompression drying device 1, first, the substrate W coated with the solution by inkjet is placed on the mounting table 20. Next, the dry pump of the exhaust device 30 is operated to decompress and exhaust the chamber 10. The decompression exhaust by the dry pump is performed until the pressure in the chamber 10 reaches, for example, 10 Pa. During the decompression exhaust, the gas in the chamber 10 is cooled by adiabatic expansion. Thus, even if the gas in the chamber 10 is cooled, the temperature of the substrate W will hardly change from the room temperature of 23° C. due to the large heat capacity of the substrate W. However, the temperature of the solvent collection net 40 having a small heat capacity will decrease.

Thereafter, the turbomolecular pump of the exhaust device 30 is operated to further perform decompression exhaust. Along with the decompression exhaust, the temperature of the solvent collection net 40 will drop to below the dew point under the pressure in the chamber 10 at that time point (e.g., 8 to 15°C) as described above. In addition, the temperature of the solvent collection net 40 is maintained below the dew point of the solvent under the pressure in the chamber 10 at each time point until the evaporation of the solvent on the substrate W is completed. Therefore, since the solvent vaporized from the substrate W is efficiently captured by the solvent collection net 40, the concentration of the gaseous solvent in the chamber 10 is maintained at a low level. Therefore, the solvent on the substrate W can be quickly removed.

Furthermore, as described above, the solvent collection net 40 is formed such that the opening ratio of the central region R1 is greater than the opening ratio of the peripheral region R2, and the heat capacity per unit area of the central region R1 in a top view is smaller than the heat capacity of the peripheral region R2. Therefore, in the cooling process of the above-mentioned decompression and exhaust, the central region R1 of the solvent collection net 40 reaches the dew point below the pressure in the chamber 10 at each time point earlier than the peripheral region R2, and as a result of the above-mentioned cooling, the central region R1 of the solvent collection net 40 reaches a lower temperature than the peripheral region R2. That is, the solvent collection net 40 has a higher solvent adsorption capacity in the central region R1 than in the peripheral region R2. Therefore, by using the solvent collection net 40, the solvent from the substrate center WC where the drying time of the solvent is longer than that of the substrate corner WP can be more efficiently collected than the solvent from the substrate corner WP when the conventional solvent collection net is used. Therefore, the time point at which the drying of the solution on the substrate W is completed can be equalized at the substrate center WC and the substrate corner WP.

After the removal of the solvent on the substrate W is completed, the exhaust device 30 continues to exhaust the turbomolecular pump. The reason is to remove the solvent captured by the solvent capture net 40 from the solvent capture net 40. For example, from the start of the turbomolecular pump to the time when the predetermined time has passed, the exhaust of the turbomolecular pump continues, thereby completing the drying process of the solvent capture net 40 to remove the solvent from the solvent capture net 40.

After the drying process of the solvent collection net 40 is completed, the exhaust device 30 is stopped. After that, after the pressure in the chamber 10 is returned to the atmospheric pressure, the substrate W is unloaded from the chamber 10. Thus, the reduced pressure drying process using the reduced pressure drying device 1 is completed.

As described above, in the present embodiment, the solvent collection net 40 is arranged to face the substrate W in the chamber 10 and is divided into a plurality of regions, openings are formed in the plurality of regions, and the heat capacity per unit area of each of the plurality of regions in a top view is different according to the portion of the substrate W facing the region. Therefore, since the solvent adsorption capacity of each of the plurality of regions of the solvent collection net 40 is different according to the portion facing the region, the drying time of the solution on the substrate W can be made uniform within the surface of the substrate W. Therefore, the deviation of the film shape within the pixel within the substrate W or the deviation of the film thickness distribution within the substrate W, and the deviation of the film thickness distribution within one pixel can be prevented. When the substrate W is enlarged, the non-uniformity of the solvent drying time within the substrate surface becomes more significant. Therefore, the reduced pressure drying apparatus 1 of this embodiment is particularly useful when a large substrate W is to be dried.

In this embodiment, the solvent collecting net 40 is divided into a central region R1 and a peripheral region R2, and openings 41 and 42 are formed in the central region R1 and the peripheral region R2, respectively. Moreover, the heat capacity per unit area of the solvent collecting net 40 is different in the central region R1 and the peripheral region R2. In the case where the substrate W to be dried is a single substrate used as a panel for an FPD, the drying time of the solution on the substrate W can be made uniform within the surface of the substrate W.

(Second embodiment) Figure 9 is a plan view of a solvent collection net installed in a decompression drying device for explaining the second embodiment. The substrate to be dried by the decompression drying device in the first embodiment is a substrate that is used as a panel for a single FPD as a whole. In contrast, the substrate W to be dried by the decompression drying device in this embodiment is a substrate that is divided into four panels for FPDs, similar to that shown in Figure 2.

The solvent collection net 100 of FIG. 9 disposed in the decompression drying device of this embodiment is divided into: a panel corresponding central region R11, which is opposite to a portion corresponding to the panel central portion PC in the substrate W; and a panel corresponding peripheral region R12, which is opposite to a portion corresponding to the panel corner portion PP in the substrate W. Moreover, the panel corresponding central region R11 is provided with an opening identical to the opening 41 of FIG. 7, and the panel corresponding peripheral region R12 is provided with an opening identical to the opening of FIG. 8. That is, the solvent collection net 100 is formed such that the opening ratio of the panel corresponding central region R11 is greater than the opening ratio of the panel corresponding peripheral region R12. Thus, in the solvent collection net 100, the heat capacity per unit area of the panel corresponding to the central region R11 in a top view is smaller than the heat capacity of the panel corresponding to the peripheral region R12.

Therefore, during the decompression and exhaust process in the chamber 10 during the decompression and drying process, the panel corresponding central area R11 of the solvent collection net 100 reaches below the dew point under the pressure in the chamber 10 at each time point earlier than the panel corresponding peripheral area R12, and the reaching temperature of the panel corresponding central area R11 is lower than that of the panel corresponding peripheral area R12. That is, the solvent collection net 100 has a higher solvent adsorption capacity in the panel corresponding central area R11 than in the panel corresponding peripheral area R12. Therefore, by using the solvent collection net 100, the solvent from the panel central part PC, where the drying time of the solvent is longer than that of the panel corner PP, can be more efficiently captured than the solvent from the panel corner PP when the conventional solvent collection net is used. Therefore, the time points at which the drying of the solution on the substrate W is completed can be made equal at the panel center PC and the panel corner PP.

According to this embodiment, when the substrate W to be dried is a single substrate that is divided and used as four FPD panels, the drying time of the solution on the substrate W can be made uniform within the panel surface.

FIG. 10 is a plan view of another example of a solvent collection net installed in a pressure reduction drying device for explaining the second embodiment. The solvent collection net used in the case where "the substrate W to be dried is a single substrate divided and used as four panels for FPD" is not limited to the example of FIG. 9 and may be as shown in FIG. 10.

The solvent collection net 110 of FIG. 10 is divided into the first to third regions R21 to R23. The first region R21 is a region opposite to the "portion of the panel center PC corresponding to the substrate center WC". The second region R22 is a region opposite to the "portion of the panel corner PP corresponding to the substrate center WC or the panel center PC corresponding to the substrate corner WP". The third region R23 is a region opposite to the "portion of the panel corner PP corresponding to the substrate corner WP". Moreover, the solvent collection net 110 forms openings in the first to third regions R21 to R23 in a manner that satisfies the following relationship. The opening ratio of the first region R21> the opening ratio of the second region R22> the opening ratio of the third region R23

Thus, in the solvent collection net 110, the heat capacity per unit area in a top view becomes the following relationship. 1st region R21＜2nd region R22＜3rd region R23

Therefore, during the process of decompression and exhaust in the chamber 10 during the decompression and drying process, the first region R21, the second region R22, and the third region R23 are in the order of reaching the dew point under the pressure in the chamber 10 at each time point. In addition, the reaching temperature during the process of decompression and exhaust is in the order of the first region R21, the second region R22, and the third region R23. That is, in the solvent collection net 110, the adsorption capacity of the solvent is from high to low in the order of the first region R21, the second region R22, and the third region R23. Furthermore, when the conventional solvent collection net is used, the solvent is dried in the order of the longer drying time, i.e., the portion opposite to the first region R21 of the solvent collection net 110 in the substrate W, the portion opposite to the second region R22, and the portion opposite to the third region R23. Therefore, by using the solvent collection net 110, the time point at which the drying of the solution on the substrate W is completed can be made equal within the surface of the substrate W and within the surface of the panel. That is, the drying time of the solution on the substrate W can be more accurately made uniform within the surface of the substrate W and within the surface of the panel. Therefore, not only can the deviation of the film shape within the pixel within the substrate W, the deviation of the film thickness distribution within the substrate W, and the deviation of the film thickness distribution within a pixel be prevented, but also the deviation of the film shape within the pixel within the panel or the deviation of the film thickness distribution within the panel can be prevented.

In addition, the second region R22 of the solvent capture net 110 can also be divided into a region opposite to the panel corner PP in the substrate center WC and a region opposite to the portion corresponding to the panel center PC in the substrate corner WP, and the heat capacity per unit area of each region when viewed from above is different from that of other divided regions.

(Third embodiment) Figure 11 is a diagram for explaining the solvent collection net installed in the decompression drying device of the third embodiment, and is a partial side view of the decompression drying device. In the decompression drying device of the above example, although one solvent collection net is used, a plurality of solvent collection nets of different shapes may be used in layers.

In the reduced pressure drying apparatus of the example of FIG11, the solvent collecting net 40 of FIG6 and the solvent collecting net 100 of FIG9 are stacked. The solvent collecting net 40 and the solvent collecting net 100 are closely attached to each other without a gap in the stacking direction, and are joined to each other by welding or the like. Regardless of the stacking order of the solvent collecting net 40 and the solvent collecting net 100, either the solvent collecting net 40 or the solvent collecting net 100 may be disposed on the substrate side W (lower side).

As described above, the solvent collecting net 40 is divided into a central region R1 and a peripheral region R2, and the solvent collecting net 100 is divided into a panel corresponding central region R11 and a panel corresponding peripheral region R12.

Even according to the present embodiment, as in the case where the solvent collection net 110 of Figure 10 is used, when the substrate W to be dried is a single substrate that is divided and used as a panel for a plurality of (for example, four) FPDs, the drying time of the solution on the substrate W can be more accurately made uniform within the surface of the substrate W and within the surface of the panel.

FIG. 12 to FIG. 14 are plan views for explaining other examples of the shape of the opening formed in the solvent collection net, and partially enlarge the solvent collection net. In the above example, the shape of the opening formed in the solvent collection net is a hexagonal shape when viewed from above, but it is not limited to this example. For example, as shown in FIG. 12, the shape of the opening 120 can also be a circular shape when viewed from above. Moreover, as shown in FIG. 13, the shape of the opening 120 is a quadrangular shape when viewed from above, and more specifically, it can also be a rectangular shape when viewed from above. Moreover, as shown in FIG. 14, the shape of the opening 120 is a triangular shape when viewed from above, and more specifically, it can also be a regular triangle shape when viewed from above.

Furthermore, the top view shape of the opening formed in the solvent collecting net may be a combination of any two or more of a hexagon, a circle, a square, and a triangle.

In the above description, the opening ratio of the solvent collection net is different for each divided area, thereby the heat capacity per unit area in a top view is different for each divided area. Alternatively, the plate thickness of the solvent collection net may be different for each divided area, thereby the heat capacity per unit area in a top view is different for each divided area. In addition, the opening ratio and the plate thickness may be different for each divided area in the solvent collection net.

The embodiments disclosed herein are illustrative in all aspects, and it should be understood that such illustrative embodiments are not intended to limit the present invention. The embodiments described above may be omitted, replaced, or modified in various forms without departing from the scope and gist of the attached patent application.

In addition, the following structures also belong to the technical scope of the present disclosure. (1) A decompression drying device is used to dry a solution applied on a substrate under decompression, and the decompression drying device is characterized by having: A solvent collection portion temporarily collects the solvent in the solution vaporized from the substrate, The solvent collection portion is arranged to face the substrate, and is divided into a plurality of regions, Openings are formed in the plurality of regions, and the heat capacity per unit area of each of the plurality of regions is different according to the portion of the substrate facing the region. According to the above (1), the drying time of the solution on the substrate can be made uniform within the substrate surface.

(2) A reduced pressure drying device as described in (1) above, wherein the solvent collection portion is formed so that the opening ratio of each of the plurality of regions is different depending on the portion of the substrate opposite to the region.

(3) A reduced pressure drying device as described in (1) or (2) above, wherein the solvent collection portion is formed such that the thickness of each of the plurality of regions is different depending on the portion of the substrate opposite to the region.

(3) A reduced pressure drying device as described in any one of (1) to (3) above, wherein the solvent collection portion is divided into: an area opposite to the corner of the substrate; and an area opposite to the center of the substrate. According to (4) above, when the substrate to be dried is a single substrate used as a panel, the drying time of the solution on the substrate can be made uniform within the substrate surface.

(5) A reduced pressure drying device as described in any one of (1) to (3) above, wherein: the substrate is divided into a plurality of panels after drying, and the solvent collection portion is divided into: a region opposite to a portion corresponding to a panel corner portion of the substrate; and a region opposite to a portion corresponding to a panel center portion of the substrate. According to (5) above, when the substrate to be dried is a substrate divided into a plurality of panels, the drying time of the solution on the substrate can be made uniform within the panel surface.

(6) A reduced pressure drying device as described in any one of (1) to (3) above, wherein: the substrate is divided into a plurality of panels after drying, and the solvent collection portion is divided into: a region opposite to the portion corresponding to the central portion of the panel in the central portion of the substrate; a region opposite to "a portion corresponding to the panel corner in the central portion of the substrate or a portion corresponding to the central portion of the panel in the corner portion of the substrate"; and a region opposite to the portion corresponding to the panel corner in the corner portion of the substrate. According to (6) above, when the substrate to be dried is a substrate divided into a plurality of panels, the drying time of the solution on the substrate can be made uniform within the substrate surface and uniform within the panel surface.

(7) A decompression drying device as described in any one of (1) to (3) above, wherein: The decompression drying device comprises: A plurality of the aforementioned solvent collecting parts; The aforementioned substrate is divided into a plurality of panels after drying; The plurality of the aforementioned solvent collecting parts are arranged in layers, including the aforementioned solvent collecting parts "divided into a region opposite to the corner of the substrate and a region opposite to the central portion of the substrate" and the aforementioned solvent collecting parts "divided into a region opposite to a portion corresponding to the corner of the panel in the aforementioned substrate and a region opposite to a portion corresponding to the central portion of the panel in the aforementioned substrate". According to the aforementioned (7), when the substrate to be dried is a substrate divided into a plurality of panels and the user selects the substrate, the drying time of the solution on the substrate can be made uniform within the substrate surface and uniform within the panel surface.

(8) A pressure-reducing drying device as described in any one of (1) to (7) above, wherein the top view shape of the opening is any one of a hexagon, a circle, a square and a triangle, or a combination of any two or more of them.

1: Pressure reduction drying device 40,100,110: Solvent collection net 41,42,120: Opening W: Substrate

[Figure 1] A plan view of a substrate coated with a solution for explaining the subject of the known technology. [Figure 2] A plan view of a substrate coated with a solution for explaining the subject of the known technology. [Figure 3] A cross-sectional view showing the schematic structure of the first embodiment of the reduced pressure drying device. [Figure 4] A top view showing the schematic structure of the first embodiment of the reduced pressure drying device. [Figure 5] A view for explaining the installation structure of the solvent collection net, and a partial side view of the reduced pressure drying device. [Figure 6] A view for explaining the installation structure of the solvent collection net, and a bottom view of the solvent collection net and its surroundings in the reduced pressure drying device. [Figure 7] A partially enlarged plan view of the central area of the solvent collection net of Figure 3. [Figure 8] A partially enlarged plan view of the peripheral area of the solvent collection net of Figure 3. [Figure 9] A plan view of a solvent collection net installed in a pressure-reducing drying device for illustrating the second embodiment. [Figure 10] A plan view of another example of a solvent collection net installed in a pressure-reducing drying device for illustrating the second embodiment. [Figure 11] A view of a solvent collection net installed in a pressure-reducing drying device for illustrating the third embodiment, and a partial side view of the pressure-reducing drying device. [Figure 12] A partially enlarged plan view of a solvent collection net for illustrating another example of the shape of the opening formed in the solvent collection net. [Figure 13] A partially enlarged plan view of a solvent collection net for illustrating another example of the shape of the opening formed in the solvent collection net. [Figure 14] A partially enlarged plan view of a solvent collection net for illustrating another example of the shape of the opening formed in the solvent collection net.

40: Solvent capture net

50:Frame

50a: Ears

R1: Central area

R2: Peripheral area

Claims (7)

A decompression drying device dries a solution applied on a substrate under decompression. The decompression drying device is characterized in that it has: a solvent collection part temporarily collecting the solvent in the solution vaporized from the substrate; the solvent collection part is arranged to face the substrate and is divided into a plurality of regions, openings are formed in the plurality of regions respectively, and the heat capacity per unit area of each of the plurality of regions is different according to the portion of the substrate facing the region; the solvent collection part is formed so that the thickness of each of the plurality of regions is different according to the portion of the substrate facing the region. As in claim 1, the reduced pressure drying device, wherein the solvent collection portion is formed such that the opening ratio of each of the plurality of regions is different depending on the portion of the substrate opposite to the region. As in claim 1 or 2, the reduced pressure drying device, wherein the solvent collection portion is divided into: an area opposite to the corner of the substrate; and an area opposite to the center of the substrate. In the reduced pressure drying device of claim 1 or 2, the substrate is divided into a plurality of panels after drying, and the solvent collection portion is divided into: a region opposite to a portion corresponding to a panel corner portion of the substrate; and a region opposite to a portion corresponding to a panel center portion of the substrate. In the reduced pressure drying device of claim 1 or 2, the substrate is divided into a plurality of panels after drying, and the solvent collection portion is divided into: an area opposite to the portion corresponding to the central portion of the panel in the central portion of the substrate; an area opposite to "a portion corresponding to the panel corner in the central portion of the substrate or a portion corresponding to the central portion of the panel in the corner of the substrate"; and an area opposite to the portion corresponding to the panel corner in the corner of the substrate. As in claim 1 or 2, the decompression drying device is provided with: a plurality of the aforementioned solvent collection parts, the aforementioned substrate is divided into a plurality of panels after drying, and the plurality of the aforementioned solvent collection parts are arranged in layers, including the aforementioned solvent collection parts "divided into a region opposite to the corner of the substrate and a region opposite to the central part of the substrate" and the aforementioned solvent collection parts "divided into a region opposite to the portion corresponding to the panel corner of the aforementioned substrate and a region opposite to the portion corresponding to the central part of the panel of the aforementioned substrate". For example, the pressure reduction drying device of claim 1 or 2, wherein the top view shape of the aforementioned opening is any one of a hexagon, a circle, a quadrilateral and a triangle, or a combination of any two or more.

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