Reduced pressure drying apparatus and reduced pressure drying method

Abstract

To provide a technique for preventing uneven drying from occurring on the vicinity of the four corners of a substrate whereon a coating film is formed.SOLUTION: A vacuum dryer 1 dries a coating film 90 coated on an effective area AE present on the upper surface of a rectangular substrate 9. The vacuum dryer 1 includes a chamber 10 that houses the substrate 9, a pressure reducing mechanism 30 for sucking gas from the chamber 10 to reduce the pressure in the chamber 10, and a cooling unit 40 for cooling a cooling face 40a facing the substrate 9. The cooling face 40a of the cooling unit 40 includes an inside area AI facing an inside portion PI separated inward from the outer edge of the effective area AE of the substrate 9, and four corner areas AC each facing corresponding four corner portions PC of the effective area AE of the substrate 9. The cooling unit 40 is structured so that the temperature of the four corner areas AC of the cooling face 40a becomes lower relative to the temperature of the inside area AI of the cooling face 40a.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a reduced pressure drying apparatus and a reduced pressure drying method. [Background technology]

[0002] Conventionally, reduced pressure drying apparatuses for reducing pressure and drying coating films such as photoresist applied to various substrates are known. The various substrates include, for example, glass substrates for forming various devices, ceramic substrates, semiconductor wafers, electronic device substrates, and printing plates for printing. The various devices include, for example, semiconductor devices, display panels, solar cell panels, magnetic disks, and optical disks. The display panels include, for example, liquid crystal display panels, organic electroluminescence (EL) display panels, plasma display panels, and field emission displays.

[0003] When drying a coating film using a reduced pressure drying device, for example, with a substrate supported by multiple support pins in the chamber, the chamber is evacuated by a vacuum pump through an exhaust port at the bottom of the chamber. This exhaust reduces the pressure in the chamber. When the pressure in the chamber decreases, the solvent in the coating film evaporates, allowing the coating film to be dried. Then, for example, when the degree of vacuum reaches a predetermined value, exhaust from the chamber is stopped, and gas is supplied into the chamber to return the pressure in the chamber to atmospheric pressure. For example, an inert gas such as nitrogen gas or air is used as the gas.

[0004] According to the technology disclosed in Patent Document 1, an ink drying device, which is a type of reduced pressure drying device, is disclosed. The ink drying device is used for drying ink that is continuously applied in the column direction between the column direction ends of a plurality of column banks arranged side by side on a substrate in each gap between adjacent column banks in the row direction. The ink includes a solute and two or more types of solvents. The ink drying device includes a chamber in which a substrate on which the ink is applied is placed, a support table on which the substrate is placed in the chamber, and a means for exhausting gas in the chamber. The means for exhausting gas controls the pressure in the chamber with a profile including a first period in which the pressure in the chamber is reduced from standard atmospheric pressure to a first pressure higher than the maximum vapor pressure among the vapor pressures of the plurality of solvents, and a second period in which the pressure in the chamber is reduced to a second pressure lower than the minimum vapor pressure among the vapor pressures of the plurality of solvents after the first period. The pressure in the chamber is reduced by 10 X When expressed as Pa (X is a real number), the average amount of change in the value of X per unit time in the second period has a larger absolute value than the average amount of change in the value of X per unit time in the first period. According to Patent Document 1, it is asserted that the ink drying device can achieve uniformity in film thickness.

[0005] According to the technology disclosed in Patent Document 2, a reduced-pressure drying apparatus is disclosed that is provided with an elevator that raises and lowers support pins that support a substrate. The elevator raises the support pins in the initial stage of depressurization, thereby narrowing the gap between the substrate and the ceiling surface of the chamber. This reduces the rate at which the pressure between the substrate and the ceiling surface decreases, thereby suppressing the occurrence of bumping in the coating film in the initial stage of depressurization. This makes it possible to suppress variations in film thickness caused by the bumping. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2018 / 131616 [Patent Document 2] Patent Publication No. 2022-086766 Summary of the Invention [Problem to be solved by the invention]

[0007] The techniques disclosed in the above Patent Documents 1 and 2 are intended to suppress drying unevenness so as to suppress film thickness variation. However, according to the inventor's investigation, the inventor has found that even the techniques in these documents cannot sufficiently suppress drying unevenness, and that drying unevenness is particularly likely to be a problem near the four corners of a rectangular substrate.

[0008] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a technique for suppressing drying unevenness that occurs near the four corners of a substrate on which a coating film is formed. [Means for solving the problem]

[0009] A first aspect is a reduced-pressure drying apparatus for drying a coating film applied to an effective area of ​​an upper surface of a rectangular substrate, comprising a chamber for accommodating the substrate, a reduced-pressure mechanism for sucking gas from the chamber to reduce the pressure in the chamber, a support part for supporting the substrate within the chamber, and a cooling part for cooling a cooling surface facing the substrate supported by the support part, wherein the cooling surface of the cooling part includes an inner region facing an inner portion away from the outer edge of the effective area of ​​the substrate to the inside, and four corner regions facing four corner portions of the effective area of ​​the substrate, and the cooling part is configured so that the temperature of the four corner regions of the cooling surface is lower than the temperature of the inner region of the cooling surface.

[0010] A second aspect is the reduced pressure drying apparatus according to the first aspect, wherein the cooling surface faces the upper surface of the substrate.

[0011] A third aspect is a reduced pressure drying apparatus according to the first or second aspect, wherein the cooling surface of the cooling section includes an enclosed region that includes the four corner regions and surrounds the inner region, and the cooling section is configured such that the temperature of the enclosed region of the cooling surface is lower than the temperature of the inner region of the cooling surface.

[0012] A fourth aspect is a reduced pressure drying apparatus according to any one of the first to third aspects, wherein the cooling section includes a plurality of cooling mechanisms that can be set to a temperature lower than room temperature in order to cool the cooling surface, and the plurality of cooling mechanisms include a main cooling mechanism that is positioned so as to overlap the outer edge of the effective area of ​​the substrate in a planar view, and at least one sub-cooling mechanism that is positioned away from the outer edge of the effective area of ​​the substrate and can be set to a temperature higher than the temperature of the main cooling mechanism.

[0013] A fifth aspect is a reduced pressure drying method for drying a coating film applied to an effective area on an upper surface of a rectangular substrate, comprising the steps of: a) placing the substrate on which the coating film has been applied in a chamber; and b) after a), drying the coating film by reducing the pressure in the chamber, wherein in b), the substrate is cooled such that the temperature of the four corners of the effective area of ​​the substrate is lower than the temperature of an inner portion away from the outer edge of the effective area of ​​the substrate. Effect of the Invention

[0014] According to each of the above aspects, when drying the coating film applied to the substrate, the temperature of the corners of the effective area of ​​the substrate is lowered compared to the temperature of the inner part of the effective area of ​​the substrate. This increases the viscosity of the coating film in the corners of the effective area of ​​the substrate. In other words, the fluidity of the coating film is reduced in the corners of the effective area of ​​the substrate. As a result, it is possible to suppress uneven drying that is likely to occur in the corners of the effective area of ​​the substrate. [Brief description of the drawings]

[0015] [Figure 1]1 is a diagram illustrating an example of a vertical cross section of a reduced-pressure drying apparatus according to a first embodiment. [Diagram 2] 1 is a diagram illustrating an example of a cross section of a reduced-pressure drying apparatus according to a first embodiment. [Diagram 3] 1 is a diagram showing an example of a vertical cross section of a reduced-pressure drying apparatus according to a first embodiment. [Figure 4] FIG. 2 is a top view illustrating an example of a substrate. [Diagram 5] FIG. 5 is an enlarged view of the area surrounded by the dashed line V in FIG. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a cross-sectional view for explaining drying unevenness of a coating film in the same field of view as FIG. 6. [Figure 8] 5 is a diagram for explaining locations on the substrate shown in FIG. 4 where drying unevenness is likely to occur. FIG. [Figure 9] FIG. 2 is a top view showing an example of a virtual section of a substrate. [Figure 10] 1 is a diagram illustrating an example of a top surface of a reduced-pressure drying apparatus according to a first embodiment. [Figure 11] 4 is a block diagram conceptually showing functions realized in a control unit. FIG. [Figure 12] 5 is a flowchart showing an example of the flow of reduced pressure drying processing according to the first embodiment. [Figure 13] FIG. 4 is a diagram illustrating an example of a state inside a chamber during a first depressurization process. [Figure 14] 11 is a diagram illustrating an example of a state inside the chamber during a second depressurization process. FIG. [Figure 15] FIG. 11 is a diagram illustrating an example of the upper surface of a reduced-pressure drying apparatus according to a second embodiment. [Figure 16] FIG. 11 is a diagram illustrating an example of the upper surface of a reduced-pressure drying apparatus according to a third embodiment. [Figure 17] FIG. 11 is a diagram illustrating an example of a vertical cross section of a reduced-pressure drying apparatus according to a fourth embodiment. [Figure 18] 13 is a flowchart showing an example of the flow of reduced pressure drying processing according to the fourth embodiment. [Figure 19] FIG. 13 is a diagram illustrating an example of a vertical cross section of a reduced-pressure drying apparatus according to a fifth embodiment. [Figure 20] FIG. 13 is a diagram illustrating an example of a vertical cross section of a reduced-pressure drying apparatus according to a sixth embodiment. [Figure 21] FIG. 13 is a diagram illustrating an example of a vertical cross section of a reduced-pressure drying apparatus according to a seventh embodiment. [Figure 22] FIG. 13 is a diagram illustrating an example of the upper surface of a reduced-pressure drying apparatus according to an eighth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment and various modified examples of the present disclosure will be described with reference to the drawings. In the drawings, parts having similar configurations and functions are given the same reference numerals, and duplicated explanations will be omitted in the following description. The drawings are shown diagrammatically, and the sizes and positional relationships of various structures in each drawing are not accurately illustrated. In addition, in this specification, the downward direction is the direction of gravity, and the upward direction is the direction opposite to the direction of gravity. The upward and downward directions are also collectively referred to as the up-down direction. Planar view means a planar layout. The planar layout of some member is a two-dimensional layout obtained by projecting the member onto a plane. The plane may be a surface perpendicular to the up-down direction.

[0017] <1. First embodiment> FIG. 1 is a diagram that shows an example of a vertical section of the reduced pressure drying apparatus 1 according to the first embodiment. FIG. 2 is a diagram that shows an example of a transverse section of the reduced pressure drying apparatus 1 according to the first embodiment. FIG. 3 is a diagram that shows an example of a vertical section of the reduced pressure drying apparatus 1 according to the first embodiment. The vertical section in FIG. 1 and the vertical section in FIG. 3 show the configuration of the reduced pressure drying apparatus 1 when viewed from directions that are different by about 90 degrees. In FIG. 3, in order to avoid complicating the drawing, configurations related to a reduced pressure mechanism 30, an air supply unit 60, a pressure gauge 70, and a control unit 80, which will be described later, are omitted for convenience.

[0018] In this embodiment, a case where the substrate 9 is used for manufacturing an organic EL (Electro Luminescence) display will be described in detail. Fig. 4 is a top view showing an example of the substrate 9. Fig. 5 is an enlarged view of the inside of the dashed line V in Fig. 4. Fig. 6 is a cross-sectional view taken along the line VI-VI in Fig. 5.

[0019] The substrate 9 is a flat substrate having a first face F1 as a first main surface and a second face F2 as a second main surface opposite to the first face F1, and has a rectangular shape in a plan view. In the reduced pressure drying apparatus 1, the first face F1 of the substrate 9 is set as the upper face of the substrate 9, and the second face F2 of the substrate 9 is set as the lower face of the substrate 9. The substrate 9 includes a glass substrate 95 (FIGS. 5 and 6). A coating film 90 is partially formed on the first face F1 of the substrate 9, for example, by applying a treatment liquid containing an organic material and a solvent in advance. The coating film 90 becomes a hole injection layer, a hole transport layer, or a light emitting layer of an organic EL display panel by drying in the reduced pressure drying apparatus 1.

[0020] A plurality of regions (also called formation regions) A1 used to actually form a product (specifically, an organic EL display) may be arranged on the first surface F1 of the substrate 9. In the example of FIG. 4, eight rectangular formation regions A1 are arranged in a matrix of four rows and two columns on the substrate 9 when viewed from above. However, the shape, number, and arrangement of the formation regions A1 are not limited to this example. The coating film 90 is formed according to a desired pattern on the upper surface of each of the formation regions A1 by an inkjet device, a slit coater, or the like in a coating process prior to the reduced pressure drying process by the reduced pressure drying device 1. In other words, the coating film 90 is not formed on the entire surface of the formation region A1, but is formed partially on the formation region A1 according to a predetermined pattern. The outside of the formation region A1 on the first surface F1 is a non-formation region A2, and the coating film 90 for forming the product is not formed in the non-formation region A2.

[0021] The first surface F1 of the substrate 9 has an effective area AE that includes all the formation areas A1. The effective area AE may be defined, for example, as an area having a minimum rectangular shape that includes all the formation areas A1. When it is difficult to determine which range of the first surface F1 is the effective area AE, the entire first surface F1 may be considered as the effective area AE, but typically, it is difficult to fully utilize the substrate 9 up to the edge of the first surface F1 for the purpose of forming a product (specifically, an organic EL display), and the first surface F1 has a margin area AN around the effective area AE.

[0022] The coating film 90 formed on the substrate 9 as described above is dried by the reduced pressure drying apparatus 1. The reduced pressure drying apparatus 1 is for drying the coating film 90 applied to the effective area AE on the upper surface of the substrate 9 having a rectangular shape.

[0023] A plurality of row banks 96 and a plurality of column banks 97 are formed on the first surface F1 of the glass substrate 95. The row banks 96 and the column banks 97 are formed in a formation area A1 (FIG. 4) of the effective area AE. The row banks 96 and the column banks 97 configure light-emitting units of the organic EL display by dividing the formation area A1 into a matrix. Thus, the extending direction of the row banks 96 and the extending direction of the column banks 97 are perpendicular to each other. In this embodiment, as shown in FIG. 6, the surface height of the column banks 97 is higher than the surface height of the row banks 96. The surface height of the coating film 90 is higher than the surface height of the row banks 96 and lower than the surface height of the column banks 97. As a result, the coating film 90 is divided by the adjacent column banks 97. Thus, a plurality of coating films 90 each extending in the y direction are arranged in the x direction. 5, in order to obtain an RGB display, coating films 90R corresponding to red (R), 90G corresponding to green (G), and 90B corresponding to blue (B) are periodically arranged in the x direction. Although not shown in Fig. 5 and Fig. 6, in addition to the above-mentioned members, the glass substrate 95 may be appropriately provided with members necessary for light emission of the organic EL display, such as an electrode layer.

[0024] As described above, each of the coating films 90 is formed in a groove extending along the y direction formed by adjacent column banks 97, so that the coating film 90 having fluidity before drying cannot flow significantly along the x direction, but can flow significantly along the y direction. As a result of this flow occurring during the drying process, the coating film 90 after drying may have a film thickness distribution accompanied by drying unevenness DV in which the film thickness is smaller at the end in the extension direction (y direction) than the approximately ideal film thickness distribution indicated by the two-dot chain line as shown in FIG. 7. Thus, referring to FIG. 8, the drying unevenness DV may occur at both ends of the effective area AE in the y direction (near the upper and lower sides of the rectangle of the effective area AE in FIG. 8), but as shown in FIG. 8, according to the study by the present inventor, it is particularly likely to occur at the four corners of the effective area AE. Therefore, it is considered that the drying unevenness DV can be suppressed by suppressing the fluidity of the coating film 90 at the four corners of the effective area AE during the drying process.

[0025] 9 is a top view showing an example of a virtual section of a substrate 9. The effective area AE of the substrate 9 (the area surrounded by a two-dot chain line in FIG. 9) has an inner portion PI that is spaced inward from the outer edge of the effective area AE, and a surrounding portion PF that surrounds the inner portion PI. The surrounding portion PF is in contact with the outer edge of the effective area AE. The surrounding portion PF has four corner portions PC and side portions PS where the drying unevenness DV (FIG. 8) is particularly likely to occur as described above. The four corner portions PC are four portions located at the four corners of the rectangular effective area AE, and are separated from each other by the side portions PS. The side portions PS are in contact with the outer edge of the effective area AE and extend along said outer edge.

[0026] Although the above description has been given in detail regarding the case where the substrate 9 is used for manufacturing an organic EL display, the substrate 9 is not limited thereto. As a modified example, the substrate 9 may include a semiconductor substrate or a ceramic substrate instead of a glass substrate. The treatment liquid for forming the coating film 90 may be, for example, a liquid containing a polyimide precursor and a solvent, or a resist liquid. For example, polyamic acid is used as the polyimide precursor. For example, NMP (N-Methyl-2-Pyrrolidone) is used as the solvent.

[0027] <1-1. Overview of the reduced pressure drying equipment configuration> Next, a description will be given of an outline of the configuration of the reduced pressure drying apparatus 1. As shown in Fig. 1 and Fig. 2, the reduced pressure drying apparatus 1 includes a chamber 10, a support section 20, a reduced pressure mechanism 30, a first lifting section 100, a cooling section 40, and a control section 80.

[0028] The chamber 10 is a portion for accommodating the substrate 9. The support portion 20 is provided in the chamber 10 and supports the substrate 9 in a horizontal position. The horizontal position here means that the thickness direction of the substrate 9 is aligned along the vertical direction.

[0029] The pressure reducing mechanism 30 sucks in the gas within the chamber 10 and exhausts the gas to the outside of the chamber 10. This suction reduces the pressure within the chamber 10. As the pressure within the chamber 10 decreases, the solvent in the coating film 90 on the first surface F1 of the substrate 9 evaporates, and the coating film 90 dries.

[0030] The cooling unit 40 cools the cooling surface 40a. However, it is not necessary to cool the entire cooling surface 40a, and in this embodiment, a part of the cooling surface 40a is actively cooled as described later. The cooling surface 40a faces the first surface F1 (upper surface) of the substrate 9 supported by the support unit 20 in the up-down direction. In the example of FIG. 1, the cooling surface 40a corresponds to the ceiling surface of the chamber 10. The cooling surface 40a may have a size larger than the substrate 9 in a top view. In other words, the cooling surface 40a may have a size that can face the entire surface of the first surface F1 of the substrate 9. The cooling surface 40a is, for example, a horizontal flat surface. The cooling unit 40 cools the cooling surface 40a, thereby lowering the temperature of the cooling surface 40a.

[0031] The vapor of the solvent (hereinafter referred to as solvent vapor) evaporated from the coating film 90 on the first surface F1 of the substrate 9 may be cooled and condensed on the cooling surface 40a. As a result, liquid solvent 91 (see also FIG. 13 described later) may adhere to the cooling surface 40a. That is, condensation of the solvent 91 may occur. In addition, a further decrease in pressure within the chamber 10 may cause the solvent 91 adhered to the cooling surface 40a to evaporate. This condensation and evaporation will also be described in detail later.

[0032] In the example of FIG. 1, the first lifting section 100 lifts and lowers the support section 20. Specifically, the first lifting section 100 lifts and lowers the support section 20 between an upper position H1 and a lower position H2. The upper position H1 is the position of the support section 20 when the interval between the substrate 9 supported by the support section 20 and the cooling surface 40a is a first interval. In the example of FIG. 1, the support section 20 and the substrate 9 positioned at the upper position H1 are shown by imaginary lines. The lower position H2 is the position of the support section 20 when the interval between the substrate 9 supported by the support section 20 and the cooling surface 40a is a second interval wider than the first interval. That is, the first lifting section 100 lifts and lowers the support section 20 between a first state in which the interval between the substrate 9 and the cooling surface 40a is a first interval, and a second state in which the interval between the substrate 9 and the cooling surface 40a is a second interval. The first interval is, for example, 10 mm or less, and a more specific example is about 5 mm. The second interval may be, for example, 5 times or more, or 10 times or more, the first interval. To explain a specific example of a numerical value, the second interval is, for example, 50 mm or more, and as a more specific example, about 80 mm.

[0033] As will be described in detail later, in the initial stage of decompression, the first lifting section 100 positions the support section 20 at the raised position H1. Thereafter, the first lifting section 100 lowers the support section 20 to the lowered position H2. The technical significance of this will also be described in detail later.

[0034] In the example of FIG. 1 and FIG. 2, the reduced pressure drying apparatus 1 further includes an air supply unit 60, a bottom surface straightening plate 50, a side surface straightening plate 51, and a pressure gauge 70. The air supply unit 60 supplies gas into the chamber 10. This allows the pressure in the chamber 10 to be returned to atmospheric pressure. The bottom surface straightening plate 50 and the side surface straightening plate 51 are provided in the chamber 10 and straighten the air flow in the chamber 10. The pressure gauge 70 measures the pressure in the chamber 10 and outputs an electric signal indicating the measurement result to the control unit 80. The control unit 80 controls various components of the reduced pressure drying apparatus 1 described above. For example, the control unit 80 controls the decompression mechanism 30 based on the pressure measured by the pressure gauge 70 to adjust the pressure in the chamber 10. In addition, the control unit 80 controls the cooling unit 40 to adjust the temperature of the cooling surface 40a and the first lifting unit 100 to adjust the position of the support unit 20.

[0035] Next, a detailed example of each component of the reduced pressure drying apparatus 1 will be described.

[0036] <1-1-1. Chamber 10> A pressure-resistant vessel having an internal space 10s for accommodating a substrate 9 is applied to the chamber 10. The chamber 10 is fixed on, for example, an apparatus frame (not shown). The shape of the chamber 10 is, for example, a flat rectangular parallelepiped. The chamber 10 has, for example, a substantially square bottom plate portion 11, four side wall portions 12, and a substantially square top plate portion 13. The four side wall portions 12 connect, for example, four end sides of the bottom plate portion 11 and four end sides of the top plate portion 13 in the up-down direction. For example, one of the four side wall portions 12 is provided with a loading / unloading port 14 and a gate portion (also called a gate valve) 15 for opening and closing the loading / unloading port 14. The gate portion 15 is, for example, linked or connected to an opening / closing drive portion 16. In FIG. 3, the opening / closing drive portion 16 is conceptually shown to avoid complication of the drawing. A driving device such as an air cylinder is applied to the opening / closing drive unit 16. Here, for example, by the operation of the opening / closing drive unit 16, the gate unit 15 can move between a position where the loading / unloading opening 14 is closed (also referred to as a closed position) and a position where the loading / unloading opening 14 is open (also referred to as an open position).

[0037] Here, for example, when the gate portion 15 is in the closed position, the internal space 10s of the chamber 10 is sealed. For example, when the gate portion 15 is in the open position, the substrate 9 can be loaded into the internal space 10s of the chamber 10 and unloaded from the internal space 10s of the chamber 10 through the load / unload opening 14.

[0038] <1-1-2. Support part 20> The support part 20 is located in the internal space 10s of the chamber 10, and can support the substrate 9 accommodated in the internal space 10s of the chamber 10 from below. The support part 20 has, for example, a plurality of support plates 21 and a plurality of support pins 22. The plurality of support plates 21 are arranged, for example, at intervals in the horizontal direction. A plurality of support pins 22 are erected on the upper surface of each support plate 21. The plurality of support pins 22 are two-dimensionally distributed and arranged when viewed from above. The plurality of support plates 21 are a base portion of the support part 20. The substrate 9 is arranged above the plurality of support plates 21, and the upper ends of the plurality of support pins 22 come into contact with a second surface F2, which is the lower surface of the substrate 9, thereby supporting the substrate 9 in a horizontal position.

[0039] <1-1-3. Pressure reducing mechanism 30> 1 and 2, the bottom plate 11 of the chamber 10 is provided with, for example, four exhaust ports 16a, 16b, 16c, and 16d in a portion facing the substrate 9 in the up-down direction. The pressure reducing mechanism 30 has, for example, an exhaust pipe 31, four individual valves Va, Vb, Vc, and Vd, a main valve Ve, and a vacuum pump 32. The exhaust pipe 31 has, for example, four individual pipes 31a, 31b, 31c, and 31d, and one main pipe 31e. For example, one end of the individual pipe 31a is connected to the exhaust port 16a, one end of the individual pipe 31b is connected to the exhaust port 16b, one end of the individual pipe 31c is connected to the exhaust port 16c, and one end of the individual pipe 31d is connected to the exhaust port 16d. For example, the other ends of the four individual pipes 31a, 31b, 31c, and 31d are joined together and connected to one end of a main pipe 31e. For example, the other end of the main pipe 31e is connected to a vacuum pump 32. For example, an individual valve Va is provided on the path of the individual pipe 31a, an individual valve Vb is provided on the path of the individual pipe 31b, an individual valve Vc is provided on the path of the individual pipe 31c, and an individual valve Vd is provided on the path of the individual pipe 31d. For example, a main valve Ve is provided on the path of the main pipe 31e.

[0040] Here, for example, when at least one of the four individual valves Va, Vb, Vc, and Vd and one main valve Ve are opened with the loading / unloading port 14 closed by the gate unit 15, and the vacuum pump 32 is operated, the gas in the chamber 10 is discharged to the outside of the chamber 10 through the exhaust pipe 31. This makes it possible to reduce the pressure in the internal space 10s of the chamber 10, for example. The four individual valves Va, Vb, Vc, and Vd are valves for individually adjusting the exhaust amount (suction flow rate) from the four exhaust ports 16a, 16b, 16c, and 16d, for example. Each of the four individual valves Va, Vb, Vc, and Vd is applied with a valve (also called an on-off valve) that can be switched between an open state and a closed state based on a command from the control unit 80, for example. The main valve Ve is a valve for adjusting the total exhaust amount from the four exhaust ports 16a, 16b, 16c, and 16d, for example. For example, a valve whose opening can be adjusted based on a command from the control unit 80 (also called an opening control valve) is used as the main valve Ve.

[0041] <1-1-4. First lifting section 100> In the first embodiment, the first lifting section 100 lifts and lowers the support section 20 in the chamber 10. In other words, the first lifting section 100 has a mechanism (also called a lifting mechanism) capable of lifting and lowering the support section 20. In FIG. 1, the first lifting section 100 is conceptually shown to avoid complication of the drawing. A driving device such as a linear motor or an air cylinder is applied to the first lifting section 100. As shown in FIG. 3, the first lifting section 100 has, for example, a main body section 100a and a moving section 100b. The main body section 100a is fixed to an apparatus frame (not shown) outside the chamber 10, for example. The moving section 100b can move, for example, in the vertical direction relative to the main body section 100a. For example, a rod-shaped member or the like is applied to the moving section 100b. The moving part 100b is positioned, for example, in a state of being inserted into the through hole 11h of the bottom plate part 11 of the chamber 10. And, for example, the support part 20 is fixed to the upper end part of the moving part 100b. Here, for example, if a bellows or the like is provided between the lower surface of the bottom plate part 11 and the moving part 100b, the gap between the bottom plate part 11 and the moving part 100b can be sealed. For example, when the supporting part 20 has a plurality of supporting plates 21, the moving part 100b has a rod-shaped part (also called a rod-shaped part) fixed to the supporting plate 21 for each supporting plate 21 and inserted into the through hole 11h of the bottom plate part 11, a part (also called a connecting part) connecting the plurality of rod-shaped parts, and a part (also called a sliding part) connected to the connecting part and slidably supported by the main body part 100a. When the first lifting part 100 lifts and lowers the supporting part 20, the substrate 9 supported by the supporting part 20 also lifts and lowers.

[0042] <1-1-5. Cooling section 40> Although the cooling principle of the cooling unit 40 is not particularly limited, in the example of FIG. 1, cooling is performed using a refrigerant. Specifically, the cooling unit 40 includes a cooling member 41, a first refrigerant pipe 42, a second refrigerant pipe 43, and a refrigerant cooling source 44. In FIG. 3, the configuration of the cooling unit 40 is shown in a simplified manner to avoid complication of the drawing. The cooling member 41 has a plate-like shape. In this case, the cooling member 41 may also be called a cooling plate. The cooling member 41 is attached to the upper surface of the top plate portion 13 with its thickness direction aligned along the vertical direction. The cooling member 41 has, for example, a rectangular shape when viewed from above. The lower surface of the cooling member 41 may be in close contact with the upper surface of the top plate portion 13. The cooling member 41 may be formed of a material with high thermal conductivity (for example, metal, etc.).

[0043] In the example of Fig. 1, a refrigerant flow path 41a is formed inside the cooling member 41. The refrigerant flow path 41a may be, for example, serpentine or may extend in a spiral shape when viewed from above. In the example of Fig. 1, an inlet 41b and an outlet 41c of the refrigerant flow path 41a are formed on the upper surface of the cooling member 41. The inlet 41b is connected to the downstream end of the first refrigerant pipe 42, and the outlet 41c is connected to the upstream end of the second refrigerant pipe 43. The upstream end of the first refrigerant pipe 42 and the downstream end of the second refrigerant pipe 43 are connected to a refrigerant cooling source 44.

[0044] The refrigerant flows into the refrigerant cooling source 44 from the downstream end of the second refrigerant pipe 43. The refrigerant may be liquid or gas. As a specific example, water can be used as the refrigerant. The refrigerant cooling source 44 cools the refrigerant and supplies the cooled refrigerant to the upstream end of the first refrigerant pipe 42. The refrigerant cooling source 44 may be, for example, a heat pump. The refrigerant cooled by the refrigerant cooling source 44 flows into the upstream end of the first refrigerant pipe 42 and flows into the refrigerant flow path 41a through the first refrigerant pipe 42. As the low-temperature refrigerant flows through the refrigerant flow path 41a, the refrigerant exchanges heat with the cooling member 41 to cool the cooling member 41. Since the cooling member 41 exchanges heat with the top plate portion 13, the top plate portion 13 is also cooled. The refrigerant that flows through the refrigerant flow path 41a and is warmed flows into the refrigerant cooling source 44 again through the second refrigerant pipe 43 and is cooled again by the refrigerant cooling source 44.

[0045] When the cooling unit 40 cools the top plate 13 of the chamber 10, the cooling surface 40a, which is the lower surface of the top plate 13 (i.e., the ceiling surface of the chamber 10), is also cooled. In the example of FIG. 1, the cooling member 41 has a size larger than the effective area AE of the substrate 9 in a plan view. That is, the outline of the cooling member 41 surrounds the outline of the effective area AE in a plan view. When the cooling member 41 and the effective area AE have a rectangular shape in a plan view, the long side of the cooling member 41 is longer than the long side of the effective area AE, and the short side of the cooling member 41 is longer than the short side of the effective area AE. The cooling member 41 may also have a square shape in a plan view. In this case, one side of the cooling member 41 may be longer than the short side of the effective area AE. According to this, regardless of the orientation of the substrate 9 arranged on the support unit 20, the cooling member 41 is larger than the effective area AE in a plan view.

[0046] FIG. 10 is a diagram that shows an example of the upper surface of the reduced pressure drying apparatus 1 according to the first embodiment. The cooling surface 40a includes an inner area AI, a surrounding area AF, and an outer area AO. In order to make the drawing easier to see, the surrounding area AF is hatched in FIG. 10. With reference to FIGS. 9 and 10, the inner area AI (FIG. 10) faces the inner part PI (FIG. 9) of the substrate 9 in the up-down direction. The surrounding area AF (FIG. 10) faces the surrounding part PF (FIG. 9) of the substrate 9 in the up-down direction. The surrounding area AF surrounds the inner area AI and includes the four corner areas AC and the side area AS. The four corner areas AC (FIG. 10) face the four corner parts PC (FIG. 9) in the up-down direction, and the side area AS (FIG. 10) faces the side part PS (FIG. 9) in the up-down direction. The outer area AO (FIG. 10) is located outside the surrounding area AF. In plan view, the outer edge of the surrounding area AF may be located outside the effective area AE so as to surround the outer edge of the effective area AE (the two-dot chain line in FIG. 10) of the substrate 9. In that case, the outer edge of the effective area AE of the substrate 9 (the two-dot chain line in FIG. 10) is included in the surrounding area AF in plan view.

[0047] The cooling unit 40 is configured such that the operation of the cooling unit 40 makes the temperature of the four corner regions AC of the cooling surface 40a lower than the temperature of the inner region AI of the cooling surface 40a. Specifically, the maximum value in the temperature distribution of the four corner regions AC may be lower than the minimum value of the temperature distribution of the inner region AI. Particularly in this embodiment, the cooling unit 40 is configured such that the operation of the cooling unit 40 makes the temperature of the surrounding region AF of the cooling surface 40a lower than the temperature of the inner region AI of the cooling surface 40a. Specifically, the maximum value in the temperature distribution of the surrounding region AF may be lower than the minimum value of the temperature distribution of the inner region AI. In other words, in this embodiment, the surrounding region AF of the cooling surface 40a is substantially the cooling region (hatched region in FIG. 10).

[0048] The temperature difference on the cooling surface 40a can be achieved by providing a cooling mechanism MF that selectively cools the surrounding area AF, which is the cooling area in this embodiment, on the cooling surface 40a. In the selective cooling of the surrounding area AF by the cooling mechanism MF, other areas other than the surrounding area AF may be cooled slightly indirectly, but the surrounding area AF is cooled more strongly than the other areas. The cooling mechanism MF that selectively cools the surrounding area AF as described above is realized, for example, by arranging the refrigerant flow path 41a (FIG. 1) in the surrounding area AF and not in the inner area AI in a plan view. In this case, the refrigerant flow path 41a does not need to be arranged in the outer area AO. As a modified example, the cooling member 41 may be arranged in the surrounding area AF and not arranged in the inner area AI in a plan view. In this case, the cooling member 41 does not need to be arranged in the outer area AO.

[0049] <1-1-6. Bottom rectifier plate 50> The bottom rectifying plate 50 is a plate for regulating the flow of gas in the internal space 10s when the pressure in the chamber 10 is reduced by the decompression mechanism 30. For example, the bottom rectifying plate 50 is disposed so as to be located between the substrate 9 supported by the support portion 20 and the bottom plate portion 11 of the chamber 10. The bottom rectifying plate 50 is fixed to the bottom plate portion 11 of the chamber 10 via a plurality of pillars not shown. As shown in FIG. 2, for example, the bottom rectifying plate 50 has a square shape in a top view. And, for example, the length of each side of the bottom rectifying plate 50 in a top view is longer than the short side of the rectangular substrate 9. For this reason, for example, regardless of the orientation of the substrate 9 arranged on the support portion 20, the bottom rectifying plate 50 is larger than the substrate 9 in a top view. Also, the bottom rectifying plate 50 has, for example, a through hole 50h through which the moving portion 100b of the first lifting and lowering portion 100 is inserted. At the through hole 50h, the bottom flow plate 50 and the moving part 100b are positioned with a very small gap therebetween.

[0050] <1-1-7. Side rectifier plate 51> The side rectifying plate 51, together with the bottom rectifying plate 50, is a plate for regulating the flow of gas in the internal space 10s when the pressure inside the chamber 10 is reduced by the decompression mechanism 30. For example, the side rectifying plate 51 is arranged so as to be located between the substrate 9 supported by the support part 20 located at the lowered position H2 and the side wall part 12 of the chamber 10. Here, for example, four side rectifying plates 51 are arranged so as to surround the periphery of the substrate 9 supported by the support part 20. For example, the four side rectifying plates 51 as a whole form a rectangular cylindrical rectifying plate surrounding the substrate 9. Also, for example, the bottom rectifying plate 50 and the four side rectifying plates 51 as a whole form a cylindrical box-shaped rectifying plate with a bottom. In the example of FIG. 1, the upper end of the side rectifying plate 51 is located below the second surface F2 of the substrate 9 supported by the support part 20 located at the raised position H1. Therefore, in the first state in which the support portion 20 is located at the raised position H1, the substrate 9 is not surrounded by the four side flow straightening plates 51.

[0051] Here, for example, when the pressure in the chamber 10 is reduced in the second state in which the support portion 20 is located at the lowered position H2, the gas directly above the substrate 9 mainly flows toward the upper end of the side rectifying plate 51 (see also FIG. 14 described later). The gas passes through the space between the side rectifying plate 51 and the side wall portion 12, the space between the bottom rectifying plate 50 and the bottom plate portion 11, and the exhaust ports 16a, 16b, 16c, and 16d in the order described, and is discharged to the outside of the chamber 10. In this way, the gas flows through a space away from the substrate 9, so that an airflow is unlikely to be formed near the substrate 9. And, the generation of a concentrated airflow is unlikely to occur at the peripheral portion of the substrate 9. This can suppress, for example, the occurrence of uneven drying of the coating film 90 formed on the upper surface of the substrate 9.

[0052] 2, a configuration is adopted in which the four exhaust ports 16a, 16b, 16c, and 16d are all located on diagonals 52 of a square bottom surface straightening plate 50 in a top view. In this case, for example, the exhaust ports 16a, 16b, 16c, and 16d can form airflows that are symmetrical with respect to the center (the intersection of the two diagonals 52) of the bottom surface straightening plate 50. This can form a more uniform airflow in the internal space 10s of the chamber 10, for example.

[0053] <1-1-8. Air supply section 60> The air supply unit 60 is a part that performs an operation of supplying gas into the chamber 10 (also referred to as air supply). As shown in FIG. 1, for example, an air supply port 16f is provided on the bottom plate portion 11 of the chamber 10. The air supply port 16f is located, for example, below the bottom surface straightening plate 50. The air supply unit 60 has an air supply pipe 61 connected to the air supply port 16f, an air supply valve Vf, and an air supply source 62. For example, one end of the air supply pipe 61 is connected to the air supply port 16f. For example, the other end of the air supply pipe 61 is connected to the air supply source 62. For example, the air supply valve Vf is provided on the path of the air supply pipe 61.

[0054] Here, for example, when the air supply valve Vf is opened, gas is supplied from the air supply source 62 to the internal space 10s of the chamber 10 via the air supply pipe 61 and the air supply port 16f. This makes it possible to increase the pressure inside the chamber 10. The gas supplied from the air supply source 62 may be, for example, an inert gas such as nitrogen gas, or may be clean dry air. The clean dry air can be prepared, for example, by purifying air in a general environment to remove particles and moisture.

[0055] <1-1-9. Pressure gauge 70> The pressure gauge 70 is a sensor that measures the pressure in the internal space 10s of the chamber 10. As shown in FIG. 1, the pressure gauge 70 is attached to a part of the chamber 10. The pressure gauge 70 can measure the pressure in the internal space 10s of the chamber 10 and output the measurement result to the control unit 80.

[0056] <1-1-10. Control unit 80> The control unit 80 is a unit (electronic circuit) for controlling the operation of each part of the reduced pressure drying apparatus 1. The control unit 80 can control the configuration of the reduced pressure mechanism 30, the cooling unit 40, the air supply unit 60, the first lifting unit 100, and the like. The control unit 80 is configured by a computer having, for example, a processor 801 such as a CPU (Central Processing Unit), a memory 802 such as a RAM (Random Access Memory), and a storage unit 803 such as a hard disk drive. The storage unit 803 stores, for example, a computer program (also called a program) 803p for executing a process (also called a reduced pressure drying process) for drying the coating film 90 on the substrate 9 by reducing pressure in the reduced pressure drying apparatus 1, and various data. The storage unit 803 stores, for example, the program 803p, and serves as a non-transitory storage medium readable by a computer. The control unit 80 controls the operation of each unit of the reduced-pressure drying apparatus 1, for example, by reading out a program 803p and data from the storage unit 803 to the memory 802 and having the processor 801 perform arithmetic processing in accordance with the program 803p and the data. Therefore, for example, the program 803p can be executed by the processor 801 included in the control unit 80 in the reduced-pressure drying apparatus 1 to perform the reduced-pressure drying process.

[0057] Further, the control unit 80 may be connected with, for example, an input unit 804, an output unit 805, a communication unit 806, and a drive 807. The input unit 804 is, for example, a unit that inputs various signals to the control unit 80 in response to a user's operation or the like. The input unit 804 may include, for example, an operation unit that inputs a signal according to a user's operation, a microphone that inputs a signal according to the user's voice, and various sensors that input a signal according to the user's movement. The output unit 805 is, for example, a unit that outputs various information in a manner that can be recognized by the user. The output unit 805 may include, for example, a display unit, a projector, and a speaker. The display unit may be a touch panel integrated with the input unit 804. The communication unit 806 is, for example, a unit that transmits and receives various information to and from an external device such as a server by wired or wireless communication means or the like. For example, a program 803p received from an external device by the communication unit 806 may be stored in the storage unit 803. The drive 807 is a part to which a portable storage medium 807m, such as a magnetic disk or an optical disk, can be attached and detached. When the storage medium 807m is attached, the drive 807 exchanges data between the storage medium 807m and the control unit 80. For example, the storage medium 807m storing the program 803p may be loaded into the drive 807, so that the program 803p may be read from the storage medium 807m and stored in the storage unit 803. Here, the storage medium 807m serves as a non-transitory storage medium that stores the program 803p and is readable by a computer.

[0058] Fig. 11 is a block diagram conceptually showing functions realized in the control unit 80. As shown in Fig. 11, the control unit 80 is electrically connected to, for example, the opening / closing drive unit 16, the first lifting unit 100, the four individual valves Va, Vb, Vc, Vd, the main valve Ve, the vacuum pump 32, the air supply valve Vf, the cooling unit 40, and the pressure gauge 70. The control unit 80 can control the operation of each of the above-mentioned units, for example, by referring to the measurement value output from the pressure gauge 70.

[0059] As conceptually shown in FIG. 11, the control unit 80 has, for example, an opening / closing control unit 81, a lifting / lowering control unit 82, a switching control unit 83, an exhaust control unit 84, a pump control unit 85, an air supply control unit 86, and a cooling control unit 87 as functional configurations to be realized. For example, the opening / closing control unit 81 controls the operation of the opening / closing drive unit 16. For example, the lifting / lowering control unit 82 controls the operation of the first lifting / lowering unit 100. For example, the switching control unit 83 individually controls the open / closed states of the four individual valves Va, Vb, Vc, and Vd. For example, the exhaust control unit 84 controls the open / closed state and the opening degree of the main valve Ve. For example, the pump control unit 85 controls the operation of the vacuum pump 32. For example, the air supply control unit 86 controls the open / closed state of the air supply valve Vf. For example, the cooling control unit 87 controls the operation of the cooling unit 40. The functions of each unit in the control unit 80 are realized, for example, by the processor 801 performing arithmetic processing according to the above-mentioned program 803p and the like.

[0060] <1-2. Reduced pressure drying process> Next, a reduced-pressure drying process for the substrate 9 using the reduced-pressure drying apparatus 1 will be described. Fig. 12 is a flow chart showing an example of the flow of the reduced-pressure drying process according to the first embodiment. This flow of the reduced-pressure drying process is realized, for example, by executing a program 803p in a processor 801 included in the control unit 80. Here, for example, the processes from step S1 to step S8 in Fig. 12 are performed in the order shown.

[0061] When performing the reduced pressure drying process using the reduced pressure drying apparatus 1, for example, first, the substrate 9 is carried into the chamber 10 (step S1). At this time, the first surface F1 of the substrate 9 has an undried coating film 90 formed thereon. Thus, the substrate 9 coated with the coating film 90 is placed in the chamber 10 by this carrying-in. In step S1, for example, the gate unit 15 opens the loading / unloading port 14 under the control of the control unit 80, and a transport robot (not shown) carries the substrate 9 into the internal space 10s of the chamber 10 through the loading / unloading port 14 of the chamber 10 while placing the substrate 9 on a fork-shaped hand. At this point, the support unit 20 is located at, for example, the lowered position H2. The side rectifying plate 51 may be configured to be movable so that the side rectifying plate 51 does not interfere with the transport robot. The transfer robot places the substrate 9 on the support part 20 while, for example, inserting a fork-shaped hand between the multiple support plates 21 of the support part 20, and then retracts the fork to the outside of the chamber 10. Then, the gate part 15 closes the load / unload port 14 under the control of the control part 80. As described above, in step S1, the process of placing the substrate 9 on the multiple support pins 22 arranged in the chamber 10 is performed.

[0062] Next, the reduced pressure drying apparatus 1 performs a cooling process (step S2). The cooling process is a process of cooling the cooling area of ​​the cooling surface 40a. Specifically, the control unit 80 operates the cooling unit 40, so that the cooling unit 40 cools the cooling area of ​​the cooling surface 40a and reduces the temperature of the cooling area of ​​the cooling surface 40a. The cooling unit 40 reduces the temperature of the cooling area of ​​the cooling surface 40a to a target temperature. The target temperature is, for example, 5 degrees Celsius or more and 15 degrees Celsius or less. As a more specific example, the target temperature is about 10 degrees Celsius. The cooling unit 40 may continue the cooling operation on the cooling surface 40a until the reduced pressure drying process on the substrate 9 is completed. The cooling operation by the cooling unit 40 may be started before step S1.

[0063] Next, the reduced pressure drying apparatus 1 performs a first gap adjustment process (step S3). The first gap adjustment process is a process for adjusting the gap between the substrate 9 and the cooling surface 40a to a first gap. Specifically, the control unit 80 controls the first lifting unit 100 to raise the support unit 20 to the raised position H1 (see FIG. 1 or FIG. 3). In the first state in which the support unit 20 is located at the raised position H1, the substrate 9 is located above the upper end of the side straightening plate 51 (see also FIG. 1).

[0064] Next, a process (steps S4 to S6) is performed in which the coating film 90 is dried by reducing the pressure inside the chamber 10. This process will be described in detail below.

[0065] The reduced-pressure drying apparatus 1 performs a first depressurization process (step S4). The first depressurization process is a process for reducing the pressure in the chamber 10 to a first pressure (hereinafter referred to as a first target pressure). The first target pressure is set to be lower than the standard atmospheric pressure, for example, 10 kPa or higher. Specifically, the control unit 80 reduces the pressure in the chamber 10 by causing the depressurization mechanism 30 to suck the gas in the chamber 10 at a small first suction flow rate. For example, the control unit 80 may reduce the opening of the main valve Ve to be smaller than the opening during the second depressurization process described below. This allows the pressure in the chamber 10 to decrease at a slower rate during the first depressurization process.

[0066] In step S3, for example, the control unit 80 may individually and appropriately control the open / close states of the individual valves Va, Vb, Vc, and Vd, thereby controlling the airflow in the chamber 10 so as to prevent the occurrence of uneven drying of the substrate 9.

[0067] 13 is a diagram showing an example of the state inside the chamber 10 during the first decompression process. In the first state in which the support 20 is located at the raised position H1 during the first decompression process, the distance between the substrate 9 and the cooling surface 40a is very narrow. Therefore, the rate at which the pressure in the upper space 10s1 decreases is lowered, and bumping of the coating film 90 on the first surface F1 of the substrate 9 can be suppressed.

[0068] On the other hand, in the first state, the substrate 9 supported by the support portion 20 is located above the upper end of the side rectifying plate 51. Therefore, the rectifying function of the side rectifying plate 51 hardly works on the upper space 10s1 between the substrate 9 and the cooling surface 40a. Therefore, the side rectifying plate 51 does not have much effect on suppressing the occurrence of uneven drying. In the first state, the lower space 10s2 below the substrate 9 is wide, so the gas in the lower space 10s2 is quickly exhausted. Specifically, the gas in the lower space 10s2 passes between the side rectifying plate 51 and the side wall portion 12 of the chamber 10 and is exhausted from the chamber 10. In FIG. 13, this air flow is shown diagrammatically by dashed arrows.

[0069] The first decompression process reduces the pressure in the chamber 10, accelerating evaporation of the solvent of the coating film 90 on the first surface F1 of the substrate 9. At this time, the first surface F1 of the substrate 9 is cooled by facing the cooling surface 40a, which has been cooled as described above, at a very narrow interval. Here, the temperature of the four corner regions AC of the cooling surface 40a facing the four corner regions PC of the substrate 9 is lower than the temperature of the inner region AI of the cooling surface 40a (FIG. 10) facing the inner portion PI of the substrate 9 (FIG. 9). Therefore, the above-mentioned cooling of the first surface F1 of the substrate 9 lowers the temperature of the four corner regions PC of the substrate 9 compared to the temperature of the inner portion PI of the substrate 9. Specifically, the maximum value in the temperature distribution of the four corner regions PC of the substrate 9 may be lower than the minimum value in the temperature distribution of the inner portion PI of the substrate 9. The viscosity of the coating film 90 on the four corner regions PC increases as the four corner regions PC of the substrate 9 are cooled. In other words, the fluidity of the coating film 90 on the four corner regions PC decreases. This makes it possible to effectively suppress the drying unevenness DV (FIG. 8) that is particularly likely to occur in the four corners PC.

[0070] In this embodiment, the temperature of the surrounding area AF of the cooling surface 40a facing the surrounding portion PF of the substrate 9 is lower than the temperature of the inner area AI of the cooling surface 40a facing the inner portion PI of the substrate 9. Therefore, the above-mentioned cooling of the first surface F1 of the substrate 9 makes the temperature of the surrounding portion PF of the substrate 9 lower than the temperature of the inner portion PI of the substrate 9. Specifically, the maximum value in the temperature distribution of the surrounding portion PF of the substrate 9 may be lower than the minimum value of the temperature distribution of the inner portion PI of the substrate 9. By cooling the surrounding portion PF of the substrate 9, the viscosity of the coating film 90 on the surrounding portion PF increases. In other words, the fluidity of the coating film 90 on the surrounding portion PF decreases. This makes it possible to suppress drying unevenness DV (FIG. 6) at the end of the coating film 90 extending in the column direction (y direction in FIG. 6) not only in the four corner portions PC but also in the side portions PS.

[0071] In this first decompression process, the target temperature of the cooling area of ​​the cooling surface 40a is set to a temperature at which the solvent vapor of the coating film 90 condenses when the pressure in the chamber 10 is the first target pressure. As a more specific example, the target temperature of the cooling area of ​​the cooling surface 40a is set to a temperature at which the pressure becomes the first target pressure on the vapor pressure curve of the solvent or lower. As a result, the solvent vapor in the chamber 10 is mainly condensed in the cooling area of ​​the cooling surface 40a of the cooling unit 40. That is, the liquid solvent 91 (FIG. 13) mainly adheres to the cooling area of ​​the cooling surface 40a. Therefore, the amount of condensation on the cooling surface 40a tends to be large in the cooling area, which is a part of the cooling surface 40a that has a relatively low temperature. In this embodiment, the cooling area of ​​the cooling surface 40a is the surrounding area AF, so the amount of condensation tends to be large in the surrounding area AF (FIG. 10). In this embodiment, the cooling area is only a part of the cooling surface 40a. If the entire cooling surface 40a were to be strongly cooled, unlike the present embodiment, the proportion of the solvent vapor evaporated from the coating film 90 that condenses on the cooling surface 40a would be high, and as a result, an excessive amount of condensation would be likely to occur in the reduced pressure drying apparatus. In contrast, in this embodiment, the inner area AI (FIG. 10) of the cooling surface 40a is not actively cooled, so the temperature of the inner area AI can be made relatively high. Therefore, the inner area AI of the cooling surface 40a can be made to not condense, or even if condensation does occur, the amount of condensation can be significantly reduced. This makes it possible to prevent an excessive amount of condensation from occurring in the reduced pressure drying apparatus 1 due to cooling.

[0072] Next, for example, when the pressure inside the chamber 10 reaches the first target pressure, the reduced pressure drying apparatus 1 performs a second gap adjustment process (step S5). The second gap adjustment process is a process for adjusting the gap between the substrate 9 and the cooling surface 40a to a second gap. Specifically, the control unit 80 controls the first lifting unit 100 to lower the support unit 20 to the lowered position H2. In the second state in which the support unit 20 is located at the lowered position H2, the substrate 9 is located below the upper end of the side straightening plate 51.

[0073] Next, the reduced-pressure drying apparatus 1 performs a second depressurization process (corresponding to step S6: second step). The second depressurization process is a process for lowering the pressure in the chamber 10 to a second pressure (hereinafter referred to as the second target pressure) lower than the first target pressure. Specifically, the control unit 80 reduces the pressure in the chamber 10 by making the depressurization mechanism 30 suck the gas in the chamber 10 at a second suction flow rate higher than the first suction flow rate. For example, the control unit 80 may increase the opening of the main valve Ve to a value larger than that in the first depressurization process. The pressure in the chamber 10 is reduced to the second target pressure at a lowering rate higher than that in the first depressurization process. In the second depressurization process, the reduced-pressure drying apparatus 1 may maintain the pressure in the chamber 10 at the second target pressure for a predetermined period of time. The second target pressure is, for example, less than 10 kPa and equal to or greater than 0.1 Pa.

[0074] Also in step S6, for example, the control unit 80 may individually and appropriately control the open / closed states of the multiple individual valves Va, Vb, Vc, and Vd. This makes it possible to control the airflow in the chamber 10 so as to suppress uneven drying DV of the substrate 9.

[0075] FIG. 14 is a diagram showing an example of the state inside the chamber 10 during the second decompression process. As shown in FIG. 14, in the second state in which the support 20 is located at the lowered position H2, the distance between the substrate 9 and the cooling surface 40a is wide. In other words, the height of the upper space 10s1 is large. Therefore, unlike the first decompression process, the solvent vapor from the coating film 90 is likely to flow upward, and the solvent vapor is unlikely to stagnate. Since the upper space 10s1 is large, the pressure inside the upper space 10s1 can be more appropriately and quickly reduced to the second target pressure.

[0076] In the second state, the substrate 9 supported by the support portion 20 is surrounded by the four side surface straightening plates 51. Therefore, the straightening function of the side surface straightening plates 51 acts on the upper space 10s1 between the substrate 9 and the cooling surface 40a. That is, the side surface straightening plates 51 can suppress the concentration of the airflow on the peripheral portion of the substrate 9. Therefore, in the second state, since the distance between the cooling surface 40a and the first surface F1 of the substrate 9 is large, the effect of suppressing the drying unevenness DV by utilizing the cooling action is small, but the drying unevenness DV can be suppressed by controlling the airflow.

[0077] When the pressure in the chamber 10 reaches the second target pressure, the solvent in the coating film 90 boils, and the drying of the coating film 90 proceeds at a higher speed. The decompression mechanism 30 may suck the gas in the chamber 10 so that the pressure in the chamber 10 is substantially constant at the second target pressure. That is, the decompression mechanism 30 may maintain the pressure in the chamber 10 at the second target pressure for a predetermined period of time. In this embodiment, the solvent 91 attached to the cooling surface 40a also evaporates in the second decompression process. In other words, the target temperature of the cooling surface 40a is set to a temperature at which the solvent evaporates when the pressure in the chamber 10 reaches the second target pressure. As a more specific example, the target temperature of the cooling surface 40a is set to a temperature at which the pressure reaches the second target pressure on the vapor pressure curve of the solvent or higher.

[0078] The solvent vapor from the coating film 90 and the cooling surface 40a flows from the upper end side of the side straightening plate 51 into the space between the side straightening plate 51 and the side wall portion 12 of the chamber 10, and is exhausted to the outside through the exhaust ports 16a, 16b, 16c, and 16d. In Fig. 14, the flow of the solvent vapor is shown diagrammatically by dashed arrows.

[0079] When the boiling of the coating film 90 is completed, that is, when a predetermined period of time has elapsed, the decompression mechanism 30 may further reduce the pressure in the chamber 10. In other words, the decompression mechanism 30 may reduce the pressure in the chamber 10 to a third target pressure that is lower than the second target pressure. This makes it possible to more reliably dry the coating film 90 and the cooling surface 40a.

[0080] As described above, in the second decompression process, the first lifting unit 100 lowers the support unit 20 to the lowered position H2, and the decompression mechanism 30 reduces the pressure in the chamber 10 to the second target pressure or less. This allows the reduced-pressure drying apparatus 1 to dry not only the coating film 90 on the first surface F1 of the substrate 9, but also the cooling surface 40a in the second decompression process.

[0081] When both the coating film 90 and the cooling surface 40a are sufficiently dried, the control unit 80 opens the air supply valve Vf. This causes gas to be supplied from the air supply source 62 through the air supply pipe 61 and the air supply port 16f to the internal space 10s of the chamber 10 (step S7). This causes the pressure inside the chamber 10 to rise again to atmospheric pressure.

[0082] Then, for example, finally, the substrate 9 is carried out from the chamber 10 (step S8). In step S8, for example, first, the gate unit 15 opens the load / unload opening 14 under the control of the control unit 80, and a transfer robot (not shown) carries the dried substrate 9 placed on the support unit 20 out of the chamber 10 via the load / unload opening 14 of the chamber 10. This may complete the reduced pressure drying process for one substrate 9.

[0083] <1-3. Summary of effects> The cooling section 40 is configured so that the temperature of the four corner regions AC (FIG. 10) of the cooling surface 40a is lower than the temperature of the inner region AI (FIG. 10) of the cooling surface 40a. This increases the viscosity of the coating film 90 in the four corner portions PC (FIG. 9) of the effective area AE of the substrate 9. In other words, the fluidity of the coating film 90 is reduced in the four corner portions PC of the effective area AE of the substrate 9. As a result, it is possible to suppress the drying unevenness DV (FIG. 8) that is likely to occur in the four corner portions PC of the substrate 9. This effect can also be obtained by other embodiments described later.

[0084] On the other hand, cooling of the substrate 9 may lead to the occurrence of condensation in the reduced pressure drying apparatus 1. If the amount of condensation is excessive, it may have an adverse effect on the implementation of the reduced pressure drying method. For example, if the condensation falls onto the substrate 9, the quality of the product using the substrate 9 may be impaired. Although the condensation can be removed by sufficiently extending the drying time under reduced pressure, this is likely to lead to an excessive decrease in productivity. In particular, in industrial applications, it is usually necessary to repeatedly operate the reduced pressure drying apparatus 1 without leaving a long interval, and as a result, even if the amount of condensation accumulated in one operation is small, an excessive amount of condensation is likely to accumulate as the operation is repeated. Regarding the problem of condensation, according to this embodiment, the cooling unit 40 is configured so that the temperature of the four corner areas AC (FIG. 10) of the cooling surface 40a is lower than the temperature of the inner area AI (FIG. 10) of the cooling surface 40a, as described above. This allows the four corner portions PC (FIG. 9) of the effective area AE of the substrate 9 to be sufficiently cooled from the viewpoint of suppressing drying unevenness DV (FIG. 8), while preventing the inner portion PI (FIG. 9) of the effective area AE of the substrate 9 from being cooled more than necessary. This makes it possible to prevent an excessive amount of condensation from occurring on the cooling surface 40a of the cooling section 40. From the above, according to this embodiment, it is possible to prevent an excessive amount of condensation from occurring on the cooling surface 40a of the cooling section 40, while suppressing drying unevenness by using cooling.

[0085] In particular, according to the reduced pressure drying apparatus 1 of this embodiment, the temperature of the surrounding area AF (FIG. 10) of the cooling surface 40a is made lower than the temperature of the inner area AI (FIG. 10) of the cooling surface 40a. This not only suppresses the drying unevenness DV in the four corners PC (FIG. 9) of the effective area AE of the substrate 9, but also suppresses the drying unevenness in the vicinity of the outer edge of the effective area AE other than the four corners PC. Specifically, it is possible to suppress the drying unevenness DV (FIG. 6) at the end of the coating film 90 extending in the column direction (y direction in FIG. 6) not only in the four corners PC but also in the side portions PS (FIG. 9).

[0086] Moreover, the cooling surface 40a (FIG. 1) faces the first surface F1 of the substrate 9. This makes it possible to efficiently cool the coating film 90 (FIG. 6) on the first surface F1.

[0087] Moreover, the ceiling surface of the chamber 10 corresponds to the cooling surface 40a of the cooling part 40. This makes it possible to configure the cooling part 40 using a general chamber 10 without the need to prepare a special chamber.

[0088] Furthermore, the support portion 20 is not only used when the substrate 9 is carried in and out, but also used to adjust the gap between the substrate 9 and the cooling surface 40a, eliminating the need to provide a dedicated mechanism just for gap adjustment.

[0089] According to the reduced pressure drying method of this embodiment, the substrate 9 is cooled so that the temperature of the four corners PC (FIG. 9) of the effective area AE of the substrate 9 is lower than the temperature of the inner portion PI (FIG. 9) of the effective area AE of the substrate 9. This makes it possible to sufficiently cool the four corners PC of the effective area AE of the substrate 9, and not to cool the inner portion PI of the effective area AE of the substrate 9 more than necessary. First, by sufficiently cooling the four corners PC of the effective area AE of the substrate 9, it is possible to suppress the drying unevenness DV (FIG. 8) that is likely to occur in the four corners PC. Second, by not cooling the inner portion PI of the effective area AE of the substrate 9 more than necessary, it is possible to prevent an excessive amount of condensation from occurring in the reduced pressure drying device. From the above, it is possible to prevent an excessive amount of condensation from occurring in the reduced pressure drying device 1 while suppressing the drying unevenness. This effect can also be obtained by other embodiments described later.

[0090] <2. Second embodiment> FIG. 15 is a diagram that shows an example of the upper surface of the reduced pressure drying apparatus 1A according to the second embodiment. The cooling section 40 (whole configuration is not shown in FIG. 15) of the reduced pressure drying apparatus 1A in this embodiment is also configured so that the temperature of the four corner regions AC of the cooling surface 40a is lower than the temperature of the inner region AI of the cooling surface 40a, as in the case of the first embodiment described above (see FIG. 10). On the other hand, in this embodiment, the cooling section 40 is configured so that the temperature of the four corner regions AC of the cooling surface 40a is lower than the temperature of the side region AS of the cooling surface 40a. Specifically, the maximum value in the temperature distribution of the four corner regions AC may be lower than the minimum value of the temperature distribution of the side region AS. In other words, in this embodiment, the four corner regions AC of the cooling surface 40a are substantially the cooling regions (hatched regions in FIG. 15).

[0091] The temperature difference on the cooling surface 40a can be achieved by providing a cooling mechanism MC that selectively cools the four corner regions AC, which are cooling regions in this embodiment, on the cooling surface 40a. As a result of the cooling by the cooling mechanism MC, other regions other than the four corner regions AC may be cooled slightly indirectly, but the four corner regions AC are cooled more strongly than the other regions. The cooling mechanism MC that selectively cools the four corner regions AC as described above is realized, for example, by arranging the refrigerant flow paths 41a (FIG. 1) in the four corner regions AC in a plan view and not arranging them in the side regions AS and the inner region AI. In this case, the refrigerant flow paths 41a do not need to be arranged in the outer region AO. As a modified example, the cooling member 41 may be arranged in the four corner regions AC in a plan view and not arranged in the side regions AS and the inner region AI. In this case, the cooling member 41 does not need to be arranged in the outer region AO.

[0092] According to this embodiment, the temperature of the four corner regions AC of the cooling surface 40a is made lower than the temperature of the side regions AS of the cooling surface 40a. In other words, the temperature of the side regions AS of the cooling surface 40a is made higher than the temperature of the four corner regions AC of the cooling surface 40a. This makes it possible to avoid unnecessarily lowering the temperature of the side regions AS. This makes it possible to more sufficiently prevent an excessive amount of condensation from occurring on the cooling surface 40a of the cooling unit 40.

[0093] <3. Third embodiment> FIG. 16 is a diagram showing an example of the upper surface of the reduced pressure drying apparatus 1B according to the third embodiment. The cooling section 40 (whole configuration is not shown in FIG. 16) of the reduced pressure drying apparatus 1B in this embodiment is also configured so that the temperature of the four corner areas AC of the cooling surface 40a is lower than the temperature of the inner area AI of the cooling surface 40a, as in the case of the first embodiment (see FIG. 10). For the purpose of cooling, in the first embodiment (FIG. 10), a single cooling mechanism MF that can be set to a temperature lower than room temperature may be provided. On the other hand, in this embodiment, the cooling section 40 includes multiple cooling mechanisms that can be set to a temperature lower than room temperature in order to cool the cooling surface 40a. These multiple cooling mechanisms include a cooling mechanism MF as a main cooling mechanism that is located so as to overlap the outer edge (two-dot chain line in FIG. 16) of the effective area AE of the substrate 9 in a plan view, and at least one sub-cooling mechanism MZ that is located outside the outer edge of the effective area AE of the substrate 9 and can be set to a temperature higher than the temperature of the cooling mechanism MF. 16, the sub-cooling mechanism MZ includes a cooling mechanism MIa that cools the inside of the cooling region of the cooling mechanism MF, a cooling mechanism MIb that cools the inside of the cooling region of the cooling mechanism MIa, a cooling mechanism MOa that cools the outside of the cooling region of the cooling mechanism MF, and a cooling mechanism MOb that cools the outside of the cooling region of the cooling mechanism MOa. If the set temperatures of these cooling mechanisms are exemplified by differences from room temperature (e.g., 20 degrees Celsius), the set temperature of the cooling mechanism MF is minus 10 degrees Celsius, the set temperature of the cooling mechanism MIa is minus 8 degrees Celsius, the set temperatures of the cooling mechanisms MIb and MOa are minus 6 degrees Celsius, and the set temperature of the cooling mechanism MOb is minus 2 degrees Celsius. The above-mentioned multiple cooling mechanisms may be configured to be able to adjust the set temperatures independently of each other.

[0094] According to this embodiment, the outer edge of the effective area AE of the substrate 9 (two-dot chain line in FIG. 16) can be locally and strongly cooled, while the vicinity thereof can be moderately and weakly cooled. The former strong cooling effectively suppresses the drying unevenness DV (FIG. 8) that is likely to occur in the surrounding portion PF of the effective area AE of the substrate 9, particularly in the four corner portions PC, and the latter cooling can also suppress the drying unevenness in the inner portion PI of the effective area AE of the substrate 9. Furthermore, by making the latter cooling moderately weak, it is possible to avoid the occurrence of an excessive amount of condensation (see solvent 91 in FIG. 13) on the cooling surface 40a of the cooling unit 40.

[0095] <4. Fourth embodiment> FIG. 17 is a diagram showing an example of a vertical cross section of a reduced pressure drying apparatus 1C according to the fourth embodiment. The reduced pressure drying apparatus 1C has the same configuration as the reduced pressure drying apparatus 1 (FIG. 1: first embodiment) except for the second lifting section 45. The second lifting section 45 lifts and lowers the cooling member 41 of the cooling section 40 between the cooling position H3 and the separated position H4. The cooling position H3 is a position where the lower surface of the cooling member 41 contacts the upper surface of the top plate section 13 of the chamber 10, and the separated position H4 is a position where the cooling member 41 is separated from the top plate section 13. In the example of FIG. 17, the cooling member 41 located at the separated position H4 is shown in a virtual line. A driving device such as a linear motor or an air cylinder is applied to the second lifting section 45.

[0096] Fig. 18 is a flow chart showing an example of the flow of the reduced pressure drying process according to the fourth embodiment. Here, for example, the processes from step S11 to step S19 in Fig. 18 are performed in this order. The cooling member 41 is initially located at the cooling position H3.

[0097] The reduced pressure drying apparatus 1C first performs steps S11 to S15 in this order. Steps S11 to S15 are the same as steps S1 to S5 (FIG. 12: first embodiment), respectively. However, the cooling operation of the cooling surface 40a by the cooling unit 40 may substantially end at step S15.

[0098] Following step S15, the reduced pressure drying apparatus 1C performs a cooling unit separation process (step S16). The cooling unit separation process is a process for moving the cooling unit 40 to the separation position H4. Specifically, the control unit 80 controls the second lifting unit 45 to raise the cooling member 41 from the cooling position H3 to the separation position H4. By raising the cooling member 41 to the separation position H4, the cooling operation on the cooling surface 40a can be substantially interrupted.

[0099] Next, the reduced pressure drying apparatus 1C performs steps S17 to S19. Steps S17 to S19 are similar to steps S6 to S8 (FIG. 12: first embodiment), respectively.

[0100] As described above, according to the fourth embodiment, in the first decompression process (step S14), the cooling member 41 descends to the cooling position H3 and cools the cooling surface 40a, which is the lower surface of the top plate portion 13. Therefore, the reduced pressure drying apparatus 1C can cool the cooling surface 40a in the first decompression process in almost the same manner as the reduced pressure drying apparatus 1 (FIG. 1: first embodiment). On the other hand, according to the fourth embodiment, in the second decompression process (step S17), the cooling member 41 ascends to the separated position H4. As a result, the cooling operation on the cooling surface 40a can be substantially interrupted in the second decompression process. As the cooling member 41 moves away from the cooling surface 40a, the temperature of the cooling surface 40a increases over time, and therefore, the evaporation of the solvent 91 condensed on the cooling surface 40a can be promoted. This makes it possible to further suppress the accumulation of condensation.

[0101] <5. Fifth embodiment> 19 is a diagram illustrating an example of a vertical cross section of a reduced-pressure drying apparatus 1D according to a fifth embodiment. The reduced-pressure drying apparatus 1D has a similar configuration to that of the reduced-pressure drying apparatus 1 (FIG. 1: first embodiment) except for the internal configuration of the cooling section 40.

[0102] As shown in FIG. 19, a part of the cooling unit 40 of the reduced pressure drying apparatus 1D is embedded in the top plate portion 13 of the chamber 10. The part of the cooling unit 40 embedded in the top plate portion 13 is a low-temperature part that absorbs heat from the top plate portion 13. This allows the top plate portion 13 to function as a cooling member 41. The top plate portion 13 may be made of a material with high thermal conductivity (e.g., metal). In the example of FIG. 19, a refrigerant flow path 41a, which is a part of the cooling unit 40, is formed inside the top plate portion 13. The refrigerant flow path 41a may meander inside the top plate portion 13 when viewed from above, or may extend in a spiral shape. In the example of FIG. 19, an inlet 41b and an outlet 41c of the refrigerant flow path 41a are formed on the upper surface of the top plate portion 13. The inlet 41b is connected to the downstream end of the first refrigerant pipe 42, and the outlet 41c is connected to the upstream end of the second refrigerant pipe 43. The refrigerant cooling source 44 cools and circulates the refrigerant, thereby cooling the top plate portion 13 of the chamber 10. In other words, the cooling surface 40a, which is the lower surface of the top plate portion 13, is cooled.

[0103] An example of the flow of the reduced pressure drying process using the reduced pressure drying apparatus 1D is similar to that of the reduced pressure drying process in the first embodiment.

[0104] According to this embodiment, the top plate 13 functions as the cooling member 41. Therefore, the number of parts of the reduced pressure drying apparatus 1D can be reduced, and the size and manufacturing cost of the reduced pressure drying apparatus 1D can be reduced. In addition, the distance between the refrigerant flow path 41a and the cooling surface 40a can be reduced, so that the cooling unit 40 can cool the cooling surface 40a with higher efficiency.

[0105] <6. Sixth Embodiment> 20 is a diagram illustrating an example of a vertical cross section of a reduced-pressure drying apparatus 1E according to a sixth embodiment. The reduced-pressure drying apparatus 1E has a similar configuration to that of the reduced-pressure drying apparatus 1 (FIG. 1: first embodiment) except for the internal configuration of the cooling section 40.

[0106] As shown in FIG. 20, a part of the cooling section 40 of the reduced pressure drying apparatus 1E is located in the internal space 10s of the chamber 10. Specifically, the cooling member 41 is located in the internal space 10s of the chamber 10. The cooling member 41 is provided in the chamber 10 at a position facing the first surface F1 of the substrate 9 supported by the support portion 20. In other words, the cooling member 41 is provided above the substrate 9 supported by the support portion 20. The cooling member 41 is provided in the chamber 10 with its thickness direction aligned along the up-down direction. The cooling member 41 is fixed to the chamber 10 through a fixing portion (not shown). The cooling member 41 may be fixed to the top plate portion 13 of the chamber 10 by a fixing portion such as a screw. In the sixth embodiment, the lower surface of the cooling member 41 corresponds to the cooling surface 40a. In the example of FIG. 20, the first refrigerant pipe 42 and the second refrigerant pipe 43 penetrate the top plate portion 13, and the refrigerant cooling source 44 is provided outside the chamber 10. The refrigerant cooling source 44 cools and circulates the refrigerant, thereby cooling the cooling member 41. That is, the cooling surface 40a of the cooling member 41 is cooled.

[0107] An example of the procedure of the reduced pressure drying process using the reduced pressure drying apparatus 1E is similar to that of the reduced pressure drying process in the first embodiment.

[0108] According to this embodiment, the cooling surface 40a is the lower surface of the cooling member 41 that is separate from the chamber 10. Therefore, the material of the cooling member 41 having the cooling surface 40a can be selected separately from the specification requirements for the chamber 10. In other words, the selectivity of the material of the cooling member 41 can be improved. In addition, since the cooling surface 40a is the lower surface of the cooling member 41, the distance between the low-temperature portion of the cooling unit 40 (here, the refrigerant flow path 41a) and the cooling surface 40a can be narrowed. Therefore, the cooling unit 40 can cool the cooling surface 40a with higher efficiency.

[0109] <7. Seventh embodiment> FIG. 21 is a diagram showing an example of a vertical cross section of the reduced pressure drying apparatus 1F according to the seventh embodiment. The reduced pressure drying apparatus 1F has a similar configuration to the reduced pressure drying apparatus 1E (FIG. 20: sixth embodiment) except for the object to be raised and lowered by the first lifting section 100. As shown in FIG. 21, the first lifting section 100 raises and lowers the cooling section 40. Specifically, the first lifting section 100 raises and lowers the cooling member 41 of the cooling section 40 between the raised position H11 and the lowered position H12. The lowered position H12 is the position of the cooling member 41 when the distance between the substrate 9 and the cooling surface 40a becomes the first distance. In FIG. 21, the cooling member 41 located at the lowered position H12 is shown by a virtual line. The raised position H11 is the position of the cooling member 41 when the distance between the substrate 9 and the cooling surface 40a becomes the second distance. In other words, the first lifting section 100 raises and lowers the cooling member 41 between a first state in which the distance between the substrate 9 and the cooling surface 40a is a first distance, and a second state in which the distance between the substrate 9 and the cooling surface 40a is a second distance.

[0110] 21, the support portion 20 is located at the lowered position H2 referred to in the first to sixth embodiments. That is, the substrate 9 supported by the support portion 20 is located at a position lower than the upper end of the side surface straightening plates 51, and is surrounded by the four side surface straightening plates 51. In the seventh embodiment, the substrate 9 is surrounded by the four side surface straightening plates 51 in both a first state in which the distance between the substrate 9 and the cooling surface 40a is a first distance, and a second state in which the distance between the substrate 9 and the cooling surface 40a is a second distance.

[0111] The lowered position H12 may be a position where the cooling surface 40a of the cooling member 41 is lower than the upper end of the side surface straightening plate 51. In other words, the cooling member 41 has a size smaller than the space surrounded by the four side surface straightening plates 51 in top view.

[0112] The raised position H11 is a position where the cooling surface 40a of the cooling member 41 is higher than the upper end of the side surface current plate 51. When the cooling member 41 is located at the raised position H11, the distance between the cooling surface 40a and the upper end of the side surface current plate 51 may be, for example, two or more times the first distance, or may be five or more times the first distance. This allows the gas directly above the substrate 9 to easily flow from the upper end side of the side surface current plate 51 into the space between the side surface current plate 51 and the side wall portion 12 of the chamber 10.

[0113] A driving device such as a linear motor or an air cylinder is applied to the first lifting part 100. The main body part 100a of the first lifting part 100 is fixed to an apparatus frame (not shown) outside the chamber 10. The moving part 100b of the first lifting part 100 can move, for example, in the vertical direction with respect to the main body part 100a. For example, a rod-shaped member or the like is applied to the moving part 100b. The moving part 100b is positioned, for example, in a state where it is inserted into the through-hole 13h of the top plate part 13 of the chamber 10. And, for example, a cooling member 41 is fixed to the lower end part of the moving part 100b. Here, for example, if a bellows or the like is provided between the upper surface of the top plate part 13 and the moving part 100b, the gap between the top plate part 13 and the moving part 100b can be sealed.

[0114] An example of the flow of the reduced pressure drying process using the reduced pressure drying apparatus 1F is similar to the reduced pressure drying process in the first embodiment. However, in the first gap adjustment process (FIG. 12: step S3), the first lifting unit 100 lowers the cooling member 41 to the lowered position H12 so that the gap between the substrate 9 and the cooling surface 40a becomes the first gap. In addition, in the second gap adjustment process (FIG. 12: step S5), the first lifting unit 100 raises the cooling member 41 to the raised position H11 so that the gap between the substrate 9 and the cooling surface 40a becomes the second gap.

[0115] According to the seventh embodiment, the cooling member 41 is separate from the chamber 10. Therefore, similar to the sixth embodiment, it is possible to improve the selectivity of the material of the cooling member 41. Furthermore, since the cooling surface 40a is the lower surface of the cooling member 41, similar to the sixth embodiment, the cooling unit 40 can cool the cooling surface 40a with higher efficiency.

[0116] Furthermore, in the seventh embodiment, even in the first state in which the gap between the substrate 9 and the cooling surface 40a is the narrower first gap, the substrate 9 supported by the support portion 20 is surrounded by the four side surface straightening plates 51. As a result, even in the first decompression process (FIG. 12: step S4), the straightening function of the four side surface straightening plates 51 acts on the upper space 10s1 between the substrate 9 and the cooling surface 40a. Therefore, the occurrence of uneven drying can be further suppressed.

[0117] In the seventh embodiment, the first lifting unit 100 lifts and lowers the cooling unit 40, but as a modified example, it may lift and lower both the support unit 20 and the cooling unit 40. In short, the first lifting unit 100 only needs to lift and lower at least one of the support unit 20 and the cooling surface 40a between a first state in which the distance between the substrate 9 supported by the support unit 20 and the cooling surface 40a is a first distance, and a second state in which the distance between the substrate 9 supported by the support unit 20 and the cooling surface 40a is a second distance wider than the first distance.

[0118] <8. Eighth Embodiment> FIG. 22 is a diagram showing an example of the upper surface of the reduced pressure drying apparatus 1G according to the eighth embodiment. The reduced pressure drying apparatus 1G has a configuration similar to that of the reduced pressure drying apparatus 1 (FIG. 1: first embodiment) except for the internal configuration of the cooling unit 40. Specifically, the reduced pressure drying apparatus 1G (FIG. 22) has a cooling member 41M having a cooling surface 40a instead of the cooling member 41 (FIG. 1: first embodiment) having a cooling surface 40a. The temperature distribution of the cooling surface 40a of the cooling member 41M may be the same as the temperature distribution of the cooling surface 40a of the cooling member 41 (FIG. 1: first embodiment). Unlike the cooling surface 40a of the cooling member 41, the cooling surface 40a of the cooling member 41M faces the second surface F2 (lower surface) of the substrate 9.

[0119] Although not shown in Fig. 22, the reduced pressure drying apparatus 1G has a support part having a function similar to that of the support part 20 of the reduced pressure drying apparatus 1. This support part can be raised and lowered between an upper position H1 and a lower position H2 (see Fig. 1) in the same manner as in the first embodiment. Also, the support part is configured to be able to load and unload the substrate 9 into and from the chamber 10 in the same manner as in the first embodiment.

[0120] The cooling section 40 of the reduced pressure drying apparatus 1G is configured to raise and lower the cooling member 41 in accordance with the raising and lowering of the support section. Although not shown in Fig. 22, the cooling section 40 of the reduced pressure drying apparatus 1G may have a refrigerant flow path 41a, a first refrigerant pipe 42, a second refrigerant pipe 43, and a refrigerant cooling source 44, similar to the cooling section 40 of the reduced pressure drying apparatus 1 (Fig. 1: first embodiment). In this embodiment, the first refrigerant pipe 42 and the second refrigerant pipe 43 penetrate the top plate portion 13.

[0121] According to this embodiment, while using a configuration in which the cooling surface 40a faces the second surface F2 of the substrate 9, it is possible to prevent an excessive amount of condensation from occurring on the cooling surface 40a of the cooling section 40 while suppressing uneven drying, roughly similar to the first embodiment.

[0122] <9. Variations> The present disclosure is not limited to the above-described embodiments and their modified examples, and various modifications and improvements can be made without departing from the gist of the present disclosure.

[0123] In each of the above embodiments, the cooling unit 40 uses a refrigerant to cool the cooling surface 40a (see FIG. 1), but the cooling principle of the cooling unit is not limited. For example, instead of a configuration using a refrigerant, a configuration using a Peltier element may be applied. In that case, the cooling unit in each of the above embodiments can be configured by optimizing the position where the Peltier element is attached in a plan view and / or optimizing the temperature control of the multiple Peltier elements. The method of attaching the Peltier element is not particularly limited, but for example, the Peltier element may be embedded in the top plate portion 13.

[0124] When the coating film 90 is formed only on a part of the effective area AE of the substrate 9 with its flow direction restricted as shown in Figures 5 and 6, the effect of reducing drying unevenness DV (Figure 8) is particularly remarkable. However, even when the coating film 90 is formed over the entire effective area AE of the substrate 9, the effect of reducing drying unevenness can be expected by applying the reduced pressure drying shown in each of the above embodiments.

[0125] The chamber 10 (see FIG. 1) has four exhaust ports 16a, 16b, 16c, and 16d, but the number of exhaust ports is arbitrary. Also, the individual valves Va, Vb, Vc, and Vd may be omitted if their effects are not required.

[0126] The chamber 10 (see FIG. 3) has a sidewall 12 provided with an entrance / exit 14 for the substrate 9, but the position of the entrance / exit is not limited thereto. For example, a structure may be adopted in which the four sidewalls 12 and the top plate 13 of the chamber 10 form an integrated lid portion, and the lid portion can be separated from the bottom plate 11 and retreated upward. In this case, for example, the lid portion may be moved up and down by the opening / closing drive unit 16 or the like. The chamber 10 can be selectively set to a state in which the lid portion contacts the bottom plate 11 via a seal material such as an O-ring to seal the internal space 10s (sealed state), and a state in which the lid portion separates upward from the bottom plate 11 to open the internal space 10s (open state). Here, when the chamber 10 is in the open state, the substrate 9 can be carried into the internal space 10s of the chamber 10 and the substrate 9 can be carried out from the internal space 10s of the chamber 10. When the chamber 10 is in a closed state, the coating film 90 on the substrate 9 can be dried by reducing pressure by exhausting air from the internal space 10s and supplying air to the internal space 10s.

[0127] The specific configuration of the support portion 20 (see FIG. 2 and FIG. 3) is an example, and other general support portions may be applied. For example, the multiple support plates 21 may be one integral support plate 21.

[0128] The bottom rectifying plate 50 (see FIG. 1) may be omitted if the effect thereof is not required. The side rectifying plate 51 (see FIG. 1) may be omitted if the effect thereof is not required.

[0129] Various operations in the reduced pressure drying apparatus 1 (see FIG. 1) may be started or ended in response to, for example, a user's operation on the input unit 804 or a signal input from an external device to the communication unit 806.

[0130] At least a part of the functional configuration realized in the control unit 80 (see FIG. 11) may be configured with hardware such as a dedicated electronic circuit.

[0131] It goes without saying that all or part of the configurations of the embodiments and modifications described above can be appropriately combined with each other within the scope of the present invention. [Explanation of symbols]

[0132] 1, 1A~1G Reduced pressure drying device 9 Substrate 10. Chamber 20 Support part 30 Pressure reducing mechanism 40 Cooling section 40a cooling surface 41, 41M Cooling material 60 Air supply section 80 Control section 90 Coating film 91 Solvent F1 Top surface (1st surface) F2 Bottom surface (2nd surface) AC four corner areas AE Effective Area AF Surrounding Area AI inner area AN margin area AO outer area AS border area DV Uneven drying MC,MF cooling mechanism MIa, MIb, MOa, MOb, MZ Cooling mechanism (sub-cooling mechanism) PC four corners PF surrounding part PI inner part PS Edge Part

Claims

1. A reduced pressure drying apparatus for drying a coating film applied to an effective area of ​​an upper surface of a rectangular substrate, comprising: a chamber for housing the substrate; a pressure reducing mechanism that sucks gas from the chamber to reduce the pressure within the chamber; a support for supporting the substrate within the chamber; a cooling unit that cools a cooling surface facing the substrate supported by the support unit; Equipped with The cooling surface of the cooling portion is an inner region facing an inner portion of the substrate spaced inward from an outer edge of the effective region; four corner regions facing four corners of the effective region of the substrate; Including, the cooling section is configured such that a temperature of the four corner regions of the cooling surface is lower than a temperature of the inner region of the cooling surface, the cooling surface faces the top surface of the substrate; a lifting unit that raises and lowers the support unit so that the gap between the cooling surface of the cooling unit and the substrate can be either a first gap of 10 mm or less, or a second gap wider than the first gap.

2. The cooling surface of the cooling portion includes a surrounding region that includes the four corner regions and surrounds the inner region, The reduced pressure drying apparatus according to claim 1 , wherein the cooling section is configured so that a temperature of the enclosed region of the cooling surface is lower than a temperature of the inner region of the cooling surface.

3. the cooling unit includes a plurality of cooling mechanisms that can be set to a temperature lower than room temperature in order to cool the cooling surface; The plurality of cooling mechanisms, in a plan view, a main cooling mechanism positioned to overlap the outer edge of the effective area of ​​the substrate; at least one sub-cooling mechanism located away from the outer edge of the effective area of ​​the substrate and configurable to a temperature higher than that of the main cooling mechanism; The reduced pressure drying apparatus according to claim 1 or 2, comprising:

4. 1. A reduced pressure drying method for drying a coating film applied to an effective area of ​​an upper surface of a rectangular substrate, comprising the steps of: a) placing the substrate coated with the coating film in a chamber; b) after step a), drying the coating film by reducing the pressure in the chamber; Equipped with In the step b), a step of suppressing a decrease in the thickness of the coating film at the four corners is performed by cooling the substrate so that the temperature of the four corners of the effective area of ​​the substrate is lower than the temperature of an inner portion of the effective area of ​​the substrate that is farther inward from the outer edge of the effective area of ​​the substrate; The reduced pressure drying method, wherein the step of suppressing a decrease in the thickness of the coating film at the four corner portions in the step b) includes a step of setting a distance between the substrate and a cooling surface of a cooling unit for cooling the substrate to 10 mm or less.

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