JP7595051B2 - Reduced-pressure drying apparatus and reduced-pressure drying method - Google Patents

Description

This disclosure relates to a reduced pressure drying device and a reduced pressure drying method.

Conventionally, reduced pressure drying apparatuses that reduce pressure and dry 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.

When drying a coating film using a reduced pressure drying device, for example, with multiple pins supporting a substrate inside the chamber, a vacuum pump evacuates the chamber through an exhaust port at the bottom of the chamber. This exhaust reduces the air pressure inside the chamber. When the air pressure inside the chamber decreases, the solvent in the coating film evaporates, allowing the coating film to dry. 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 inside the chamber to atmospheric pressure. For example, an inert gas such as nitrogen gas or air is used as the gas.

However, in a reduced pressure drying apparatus, if the air pressure in the chamber is suddenly lowered at the beginning of the decompression process, bumping may occur in the coating film on the substrate. If bumping occurs, for example, the thickness of the coating film may vary.

The reduced pressure drying apparatus described in Patent Document 1 is capable of suppressing the occurrence of such bumping. The reduced pressure drying apparatus described in Patent Document 1 is provided with a lifting section that raises and lowers the support pins that support the substrate. The lifting section raises the support pins at the beginning of the decompression, thereby narrowing the gap between the substrate and the ceiling surface of the chamber. This reduces the rate at which the air pressure between the substrate and the ceiling surface drops, making it possible to suppress the occurrence of bumping.

JP 2022-086766 A

However, when the distance between the substrate and the ceiling surface becomes narrow, the solvent vapor from the coating film on the substrate becomes trapped in the space between the substrate and the ceiling surface. In particular, the solvent vapor from near the center of the coating film is prone to stagnation. That is, although the solvent vapor from near the periphery of the coating film can flow outward in the horizontal direction due to concentration diffusion, it remains trapped near the center of the coating film because the concentration gradient is small near the center. For this reason, the solvent in the coating film is more likely to evaporate in the periphery than in the center. In other words, this leads to uneven drying of the coating film. Uneven drying can cause problems, such as variations in the thickness of the dried coating film.

This disclosure was made in consideration of the above problems, and aims to provide a technology that suppresses the occurrence of drying unevenness in a coating film.

A first aspect is a reduced-pressure drying apparatus for drying a coating film applied to an upper surface of a substrate, the apparatus comprising: a chamber for accommodating the substrate; a support part for supporting the substrate within the chamber; a cooling part for cooling a cooling surface facing the upper surface of the substrate supported by the support part; a first lifting part for raising and lowering at least one of the support part and the cooling surface between a first state in which a distance between the substrate supported by the support part and the cooling surface is a first distance and a second state in which a distance between the substrate supported by the support part and the cooling surface is a second distance wider than the first distance; a decompression mechanism for sucking in gas within the chamber to reduce the air pressure within the chamber; and a control part for controlling the first lifting part and the decompression mechanism so that the air pressure within the chamber is set to a first air pressure in the first state and then to a second air pressure lower than the first air pressure in the second state.
A second aspect is a reduced pressure drying apparatus according to the first aspect, wherein the control unit controls the cooling unit to cool the cooling surface to a temperature below the temperature at which the pressure becomes the first atmospheric pressure on a vapor pressure curve of the solvent on the substrate in the first state, and above the temperature at which the pressure becomes the second atmospheric pressure on the vapor pressure curve in the second state.
A third aspect is a reduced pressure drying apparatus according to the first or second aspect, wherein the control unit reduces the air pressure in the chamber to the first air pressure in the first state, thereby evaporating the solvent of the coating film on the substrate while condensing the solvent vapor on the cooling surface, and reduces the air pressure in the chamber to the second air pressure in the second state, thereby evaporating both the solvent of the coating film on the substrate and the solvent on the cooling surface, thereby drying the coating film and the cooling surface.

A fourth aspect is the reduced pressure drying apparatus according to the first or second aspect, wherein the cooling surface is a ceiling surface of the chamber, and the first lifting unit lifts and lowers the support unit.

A fifth aspect is a reduced pressure drying apparatus according to the fourth aspect, wherein the cooling unit is attached to an upper surface of a top plate of the chamber and cools the top plate to cool the cooling surface, which is the underside of the top plate.

A sixth aspect is a reduced pressure drying apparatus according to the fifth aspect, further comprising a second lifting unit that raises and lowers the cooling unit between a cooling position in contact with the upper surface of the top plate unit and a spaced position away from the top plate unit.

A seventh aspect is the reduced pressure drying apparatus according to the fourth aspect, wherein at least a portion of the cooling unit is embedded in a top plate portion of the chamber.

An eighth aspect is the reduced pressure drying apparatus according to the first or second aspect, wherein the cooling unit includes a cooling member that is provided within the chamber and has the cooling surface as a lower surface.

A ninth aspect is the reduced pressure drying apparatus according to the eighth aspect, wherein the first lifting unit lifts and lowers the cooling member.
A tenth aspect is a reduced pressure drying apparatus according to the ninth aspect, further comprising a side baffle plate surrounding the substrate supported by the support portion, and a bottom baffle plate facing the underside of the substrate supported by the support portion , and in both the first state and the second state, the substrate supported by the support portion is surrounded by the side baffle plate.

An eleventh aspect is a reduced-pressure drying method for drying a coating film applied to an upper surface of a substrate, comprising: a first step of cooling a cooling surface facing the upper surface of the substrate supported by a support part in a chamber, and reducing the air pressure in the chamber to a first air pressure while a distance between the substrate and the cooling surface is a first distance, thereby evaporating a solvent in the coating film on the substrate and condensing the solvent vapor on the cooling surface; and a second step of reducing the air pressure in the chamber to a second air pressure lower than the first air pressure after the first step, while a distance between the substrate and the cooling surface is a second distance wider than the first distance, thereby evaporating both the solvent in the coating film on the substrate and the solvent on the cooling surface, thereby drying the coating film and the cooling surface.

A twelfth aspect is a reduced pressure drying method according to the eleventh aspect, wherein in the first step, a cooling unit is lowered to a cooling position in contact with an upper surface of a top plate portion of the chamber to cool the cooling surface, which is the underside of the top plate portion, and in the second step, the cooling unit is raised to a spaced position away from the top plate portion of the chamber.

According to the first to third aspects , in the first state, the gas in the chamber is lowered to a first atmospheric pressure. This causes the solvent in the coating film to evaporate. In the first state, the gap between the substrate and the cooling surface is narrow, so that the occurrence of bumping in the coating film can be suppressed. On the other hand, the solvent vapor from the coating film immediately collides with the cooling surface and cannot diffuse upward. Although the solvent vapor flows horizontally outward due to concentration diffusion near the periphery of the coating film, it is difficult to flow outward near the center of the coating film and is likely to remain there. Therefore, in terms of the flow of solvent vapor, the solvent in the coating film is more likely to evaporate in the peripheral portion than in the central portion, which can cause drying unevenness. However, according to the first to third aspects , the cooling unit cools the cooling surface. Therefore, the solvent vapor can be condensed on the cooling surface. Therefore, the solvent vapor is less likely to remain near the center of the coating film, and the difference in the amount of evaporation between the central portion and the peripheral portion of the coating film can be reduced. In other words, the occurrence of drying unevenness in the coating film can be suppressed.

Then, in the second state, the air pressure inside the chamber drops further, so the solvent in the coating film on the substrate evaporates further. In the second state, the gap between the substrate and the cooling surface is wide, so the solvent vapor easily diffuses upward. For this reason, in the second state, uneven drying of the coating film is less likely to occur. Moreover, because the air pressure inside the chamber drops further, the solvent adhering to the cooling surface can also evaporate, so that not only the coating film but also the cooling surface can be dried.

According to the fourth aspect, the existing first lifting section can be reused.

According to the fifth aspect, the variation in temperature distribution in top view is mitigated from the upper surface of the top plate to the lower surface (cooling surface) due to heat transfer in the top plate. In other words, the temperature distribution on the cooling surface can be made more uniform. Therefore, the solvent vapor from the coating film condenses more uniformly (in other words, more uniformly) on the cooling surface. Therefore, the uniformity of the concentration distribution between the substrate and the cooling surface can be improved, and the occurrence of uneven drying of the coating film can be further suppressed.

According to the sixth aspect, in the second state, the second lifting unit raises the cooling unit to the separated position, thereby raising the temperature of the cooling surface, thereby making it possible to more reliably dry the cooling surface.

According to the seventh aspect, the cooling portion can cool the cooling surface with high efficiency.

According to the eighth and ninth aspects, the material of the cooling member can be selected separately from the material of the chamber.

According to the tenth aspect, the side air rectifying plate surrounds the substrate in both the first state and the second state. Therefore, the concentration of the air flow on the peripheral portion of the substrate can be suppressed in both the first state and the second state. Therefore, the occurrence of uneven drying due to the air flow can be suppressed.

According to the eleventh aspect, in the first step, the pressure in the chamber is reduced to the first pressure, and the solvent in the coating film evaporates. In the first step, the gap between the substrate and the cooling surface is narrow, so that the occurrence of bumping in the coating film can be suppressed. On the other hand, the solvent vapor from the coating film immediately collides with the cooling surface and cannot diffuse upward. Although the solvent vapor flows horizontally outward due to concentration diffusion near the periphery of the coating film, it is difficult to flow outward near the center of the coating film and is likely to remain there. Therefore, from the viewpoint of the flow of the solvent vapor, the solvent in the coating film is more likely to evaporate in the peripheral portion than in the central portion, and drying unevenness may occur. However, according to the eleventh aspect, the cooling surface is cooled, so that the solvent vapor is condensed on the cooling surface. Therefore, the solvent vapor is unlikely to remain even near the center of the coating film, and the difference in the amount of evaporation between the central portion and the peripheral portion of the coating film can be reduced. Therefore, the occurrence of drying unevenness in the coating film can be suppressed.

In the second step, the air pressure inside the chamber is reduced to a lower second air pressure. This allows the solvent in the coating film on the substrate to further evaporate. In the second step, the gap between the substrate and the cooling surface is wide, so the solvent vapor easily diffuses upward. As a result, in the second step, uneven drying of the coating film is less likely to occur. Moreover, because the air pressure inside the chamber is further reduced, the solvent on the cooling surface can also evaporate, allowing not only the coating film but also the cooling surface to be dried.

According to the twelfth aspect, in the first step, the solvent vapor can be more reliably condensed on the cooling surface, while in the second step, the cooling surface can be more reliably dried.

1 is a diagram illustrating an example of a vertical cross section of a reduced-pressure drying apparatus according to a first embodiment. 1 is a diagram illustrating an example of a cross section of a reduced pressure drying apparatus according to a first embodiment. FIG. 1 is a diagram showing an example of a vertical cross section of a reduced-pressure drying apparatus according to a first embodiment. FIG. FIG. 2 is a perspective view showing an example of a substrate. FIG. 2 is a diagram showing an example of a vertical cross section of a portion of a substrate. 4 is a block diagram conceptually showing functions realized in a control unit. FIG. 4 is a flowchart showing an example of the flow of reduced pressure drying processing according to the first embodiment. 1A and 1B are diagrams each showing an example of a state inside a chamber during a first depressurization process; 1 is an enlarged view showing the vicinity of a cooling surface and a substrate in a chamber during a first depressurization process; FIG. 13 is an enlarged view showing a top plate portion and a substrate of a chamber according to a comparative structure. FIG. FIG. 13 is a diagram showing an example of a concentration distribution of solvent vapor in an upper space in a comparative structure. FIG. 13 is a diagram showing an example of a concentration distribution of solvent vapor in the upper space when the cooling unit is cooling. FIG. 13 is a diagram illustrating an example of a state inside the chamber during a second depressurization process. FIG. 11 is a diagram illustrating an example of a vertical cross section of a reduced pressure drying apparatus according to a second embodiment. 10 is a flowchart showing an example of the flow of reduced pressure drying processing according to a second embodiment. FIG. 11 is a diagram illustrating an example of a vertical cross section of a reduced-pressure drying apparatus according to a third embodiment. FIG. 13 is a diagram illustrating an example of a vertical cross section of a reduced-pressure drying apparatus according to a fourth embodiment. FIG. 13 is a diagram illustrating an example of a vertical cross section of a reduced pressure drying apparatus according to a fifth embodiment.

Below, 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 size and positional relationship of various structures in each figure are not accurately illustrated. Furthermore, in this specification, the downward direction is the direction of gravity, and the upward direction is the direction opposite to the direction of gravity.

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 complication of the drawing, configurations related to a decompression mechanism 30, an air supply unit 60, a barometer 70, and a control unit 80, which will be described later, are omitted for convenience.

The reduced pressure drying device 1 is a device that dries the coating film 90 (see Figure 5) formed on the upper surface of the substrate 9.

The substrate 9 may be, for example, a glass substrate, a semiconductor wafer, or a ceramic substrate. The substrate 9 is, for example, a flat substrate having a first surface F1 (see FIGS. 4 and 5) as a first main surface and a second surface F2 (see FIG. 5) as a second main surface opposite to the first surface F1. For example, in the reduced pressure drying device 1, the first surface F1 of the substrate 9 is the upper surface of the substrate 9, and the second surface F2 of the substrate 9 is the lower surface of the substrate 9. Here, a specific example in which a rectangular glass substrate is applied to the substrate 9 will be described as appropriate. A coating film 90 is partially formed on the first surface F1 of the substrate 9 by applying a treatment liquid containing, for example, an organic material and a solvent in advance. The treatment liquid is applied, for example, by a slit coater or an inkjet device. The treatment liquid may be, for example, a liquid containing a polyimide precursor and a solvent (also called a PI liquid) or a coating liquid such as a resist liquid. The polyimide precursor may be, for example, a polyamic acid (polyamic acid). For example, NMP (N-Methyl-2-Pyrrolidone) is used as the solvent. In addition, for example, when the reduced pressure drying apparatus 1 is applied to the manufacturing process of an organic EL display, a mode may be adopted in which 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 being dried in the reduced pressure drying apparatus 1.

4 is a perspective view showing an example of the substrate 9. FIG. 5 is a view showing an example of a vertical cross section of a portion of the substrate 9. As shown in FIG. 4, the substrate 9 has, for example, a rectangular shape with different vertical and horizontal lengths when viewed from above. A plurality of regions (also called formation regions or coating regions) A1 in which devices or the like are formed are arranged on the substrate 9. In the example of FIG. 4, four rectangular coating regions A1 are arranged in a matrix of two rows and two columns on the substrate 9 when viewed from above. However, the shape, number, and arrangement of the coating 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 coating region A1 by a slit coater or inkjet device or the like in a coating process prior to the reduced pressure drying process by the reduced pressure drying device 1. For example, a circuit pattern is applied to the desired pattern. Here, for example, as shown in FIG. 5, the first face F1 as the upper surface of each coating region A1 has a region A3 covered with the coating film 90 (also called a covered region) and an exposed region A4 not covered with the coating film 90 (also called an exposed region). In addition, the region around the coating region A1 and between adjacent coating regions A1 on the substrate 9 is a region A2 (also called a non-coated region) where the coating film 90 is not formed on the first face F1 as the upper surface. The non-coated region A2 is also an exposed region A4 not covered with the coating film 90.

<1-1. Overview of the configuration of the reduced pressure drying device>
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 unit 20, a decompression mechanism 30, a first lifting unit 100, a cooling unit 40, and a control unit 80.

The chamber 10 is a portion for housing the substrate 9. The support portion 20 is provided within 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 in the vertical direction.

The pressure reduction mechanism 30 sucks in the gas in the chamber 10 and expels the gas to the outside of the chamber 10. This suction reduces the air pressure in the chamber 10. As the air pressure in 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.

The cooling unit 40 cools the cooling surface 40a. The cooling surface 40a is a surface that faces the first surface F1 of the substrate 9 supported by the support unit 20 in the vertical 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 when viewed from above. In other words, the cooling surface 40a may have a size that allows it to face the entire 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.

The solvent vapor (hereinafter referred to as solvent vapor) that has 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. 8, which will be described later) may adhere to the cooling surface 40a. This condensation can suppress the occurrence of uneven drying of the coating film 90, as will be described in detail later. In addition, a further reduction in the air pressure within the chamber 10 can also evaporate the solvent 91 that has adhered to the cooling surface 40a. This condensation and evaporation will also be described in detail later.

In the example of FIG. 1, the first lifting unit 100 lifts and lowers the support unit 20. Specifically, the first lifting unit 100 lifts and lowers the support unit 20 between an elevated position H1 and a lowered position H2. The elevated position H1 is the position of the support unit 20 when the distance between the substrate 9 supported by the support unit 20 and the cooling surface 40a is a first distance. In the example of FIG. 1, the support unit 20 and the substrate 9 positioned at the elevated position H1 are shown by imaginary lines. The lowered position H2 is the position of the support unit 20 when 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. In other words, the first lifting unit 100 lifts and lowers the support unit 20 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. The first distance 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 give a specific example of a numerical value, the second interval is, for example, 50 mm or more, and a more specific example is about 80 mm.

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

1 and 2, the reduced pressure drying apparatus 1 further includes an air supply unit 60, a bottom rectifying plate 50, a side rectifying plate 51, and a barometer 70. The air supply unit 60 supplies gas into the chamber 10. This allows the air pressure in the chamber 10 to be returned to atmospheric pressure. The bottom rectifying plate 50 and the side rectifying plate 51 are provided in the chamber 10 and adjust the air flow in the chamber 10. The barometer 70 measures the air pressure in the chamber 10 and outputs an electrical 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 air pressure measured by the barometer 70 to adjust the air pressure in the chamber 10. The control unit 80 also 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.

Next, a detailed example of each component of the reduced pressure drying device 1 will be described.

<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 transfer port 14 and a gate portion (also called a gate valve) 15 for opening and closing the transfer 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 in order 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).

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 via the loading/unloading port 14.

<1-1-2. Support part 20>
The support portion 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 portion 20 includes, for example, a plurality of support plates 21. The support plates 21 are arranged, for example, at intervals in the horizontal direction. Each support plate 21 has a plurality of support pins 22 standing upright on its upper surface. The support pins 22 are two-dimensionally distributed when viewed from above. The support plates 21 are bases of the support portion 20. The substrate 9 is disposed above the support plates 21. The upper ends of the support pins 22 come into contact with a second face F2, which serves as the lower face of the substrate 9, thereby supporting the substrate 9 in a horizontal position.

<1-1-3. Pressure reducing mechanism 30>
1 and 2, for example, four exhaust ports 16a, 16b, 16c, and 16d are provided in a portion of the bottom plate portion 11 of the chamber 10 that faces the substrate 9 in the up-down direction. The pressure reduction 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, the individual valve Va is provided on the path of the individual pipe 31a, the individual valve Vb is provided on the path of the individual pipe 31b, the individual valve Vc is provided on the path of the individual pipe 31c, and the individual valve Vd is provided on the path of the individual pipe 31d. For example, the main valve Ve is provided on the path of the main pipe 31e.

Here, for example, when the gate unit 15 closes the loading/unloading port 14, at least one of the four individual valves Va, Vb, Vc, and Vd and one main valve Ve are opened, 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 allows, for example, the air pressure in the internal space 10s of the chamber 10 to be reduced. The four individual valves Va, Vb, Vc, and Vd are, for example, valves for individually adjusting the exhaust amount (suction flow rate) from the four exhaust ports 16a, 16b, 16c, and 16d. Each of the four individual valves Va, Vb, Vc, and Vd is, for example, a valve (also called an opening/closing valve) that can be switched between an open state and a closed state based on a command from the control unit 80. The main valve Ve is, for example, a valve for adjusting the total exhaust amount from the four exhaust ports 16a, 16b, 16c, and 16d. The main valve Ve is, for example, a valve whose opening can be adjusted based on a command from the control unit 80 (also called an opening control valve).

<1-1-4. First lifting section 100>
In the first embodiment, the first lifting unit 100 lifts and lowers the support unit 20 in the chamber 10. In other words, the first lifting unit 100 has a mechanism (also called a lifting mechanism) that can lift and lower the support unit 20. In FIG. 1, the first lifting unit 100 is conceptually shown in order to avoid complication of the drawing. A driving device such as a linear motor or an air cylinder is applied to the first lifting unit 100. As shown in FIG. 3, the first lifting unit 100 has, for example, a main body unit 100a and a moving unit 100b. The main body unit 100a is fixed to an apparatus frame (not shown) outside the chamber 10. The moving unit 100b can move, for example, in the vertical direction relative to the main body unit 100a. For example, a rod-shaped member or the like is applied to the moving unit 100b. The moving part 100b is positioned, for example, in a state where it is 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.

<1-1-5. Cooling section 40>
Although the specific configuration of the cooling unit 40 is not particularly limited, in the example of FIG. 1, 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 order to avoid complicating the drawing, the configuration of the cooling unit 40 is shown in a simplified manner in Fig. 3. The cooling member 41 has a plate shape. In this case, the cooling member 41 is also called a cooling plate. The cooling member 41 is attached to the upper surface of the top plate 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 is It is preferable that the cooling member 41 is in close contact with the upper surface of the top plate portion 13. The cooling member 41 may be made of a material with high thermal conductivity (such as a metal).

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 spiral when viewed from above. In the example of FIG. 1, the inlet 41b and 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 the refrigerant cooling source 44.

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 back into the refrigerant cooling source 44 through the second refrigerant pipe 43 and is cooled again by the refrigerant cooling source 44.

When the cooling unit 40 cools the top plate portion 13 of the chamber 10, the cooling surface 40a, which is the lower surface of the top plate portion 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 substrate 9 in a top view. That is, the contour of the cooling member 41 surrounds the contour of the substrate 9 in a top view. When the cooling member 41 has a rectangular shape in a top view, the long side of the cooling member 41 is longer than the long side of the substrate 9, and the short side of the cooling member 41 is longer than the short side of the substrate 9. This allows the cooling member 41 to appropriately cool the entire surface of the cooling surface 40a that faces the entire first surface F1 of the substrate 9. The cooling member 41 may also have a square shape in a top view. In this case, one side of the cooling member 41 may be longer than the short side of the substrate 9. According to this, regardless of the orientation of the substrate 9 placed on the support portion 20, the cooling member 41 is larger than the substrate 9 in a top view. Therefore, regardless of the orientation of the substrate 9, the cooling member 41 can appropriately cool the entire surface of the cooling surface 40a that faces the entire first surface F1 of the substrate 9.

<1-1-6. Bottom rectifier plate 50>
The bottom flow regulating 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 pressure reducing mechanism 30. For example, the bottom flow regulating plate 50 is a plate for regulating the flow of gas in the internal space 10s when the substrate 9 is supported by the support portion 20. and the bottom plate 11 of the chamber 10. The bottom flow plate 50 is fixed to the bottom plate 11 of the chamber 10 via a plurality of pillars (not shown), for example. As shown in FIG. 2, for example, the bottom rectifying plate 50 has a square shape in top view. And, for example, the length of each side of the bottom rectifying plate 50 in top view is 1/100 of a rectangular shape. For this reason, for example, regardless of the orientation of the substrate 9 placed on the support portion 20, the bottom flow straightening plate 50 is larger than the substrate 9 when viewed from above. The plate 50 has, for example, a through hole 50h through which the moving part 100b of the first lifting part 100 is inserted. At the through hole 50h, the bottom flow plate 50 and the moving portion 100b are positioned with a very small gap therebetween.

<1-1-7. Side rectifier plate 51>
The side flow plate 51, together with the bottom flow 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 pressure reduction mechanism 30. For example, the side flow plate 51 is in the lowered position H2 The support 20 is disposed between the substrate 9 supported by the support 20 and the side wall 12 of the chamber 10. Four side rectifying plates 51 are arranged so as to surround the substrate 9. For example, the four side rectifying plates 51 as a whole form a rectangular tubular rectifying plate surrounding the substrate 9. The bottom surface straightening plate 50 and the four side surface straightening plates 51 as a whole form a cylindrical box-shaped straightening plate with a bottom. In the example of FIG. 1, the upper end of the side surface straightening plate 51 is in the raised position. It is located below the second surface F2 of the substrate 9 supported by the support portion 20 located at 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.

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 straightening plate 51 (see also FIG. 13 described later). The gas passes through the space between the side straightening plate 51 and the side wall portion 12, the space between the bottom straightening plate 50 and the bottom plate portion 11, and the exhaust ports 16a, 16b, 16c, and 16d in the order described above, and is discharged to the outside of the chamber 10. In this way, the gas flows through a space away from the substrate 9, making it difficult for an air flow to be formed near the substrate 9. And it becomes difficult for a concentrated air flow to occur at the periphery 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.

In addition, as shown in FIG. 2, a configuration is adopted in which the four exhaust ports 16a, 16b, 16c, and 16d are all located on the diagonals 52 of the square-shaped bottom air straightening plate 50 when viewed from above. In this case, for example, each exhaust port 16a, 16b, 16c, and 16d can form an airflow that is symmetrical with respect to the center of the bottom air straightening plate 50 (the intersection of the two diagonals 52). This can form a more uniform airflow in the internal space 10s of the chamber 10, for example.

<1-1-8. Air supply section 60>
The gas supply unit 60 is a part that supplies gas (also called gas supply) into the chamber 10. As shown in FIG. 1, the bottom plate 11 of the chamber 10 has, for example, a gas supply port 16f. The air supply port 16f is located, for example, below the bottom surface straightening plate 50. The air supply unit 60 includes an air supply pipe 61 connected to the air supply port 16f and an air supply valve Vf. 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.

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 air 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 may be prepared, for example, by purifying the air in a general environment to remove particles and moisture.

<1-1-9. Barometer 70>
The barometer 70 is a sensor that measures the air pressure in the internal space 10s of the chamber 10. As shown in Fig. 1, the barometer 70 is attached to a part of the chamber 10. The barometer 70 measures the air pressure in the internal space 10s of the chamber 10 and can output the measurement result to the control unit 80.

<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-transient storage medium that can be read by a computer. The control unit 80 controls the operation of each part 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 performing arithmetic processing in accordance with the program 803p and the data in the processor 801. 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.

The control unit 80 may also be connected to, 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, etc. The input unit 804 may include, for example, an operation unit that inputs a signal corresponding to the user's operation, a microphone that inputs a signal corresponding to the user's voice, and various sensors that input signals corresponding 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, etc. For example, the 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 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, when the storage medium 807m storing the program 803p is attached to the drive 807, the program 803p may be read from the storage medium 807m and stored in the storage unit 803. Here, the storage medium 807m stores the program 803p, for example, and serves as a non-transitory storage medium that can be read by a computer.

Figure 6 is a block diagram conceptually illustrating the functions realized by the control unit 80. As shown in Figure 6, 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 barometer 70. The control unit 80 can control the operation of each of the above-mentioned units, for example, by referring to the measurement values output from the barometer 70.

6, the control unit 80 has, for example, an opening/closing control unit 81, a lifting 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 control unit 82 controls the operation of the first lifting unit 100. For example, the switching control unit 83 individually controls the opening/closing state of the four individual valves Va, Vb, Vc, and Vd. For example, the exhaust control unit 84 controls the opening/closing 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 opening/closing 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, etc.

<1-2. Reduced pressure drying treatment>
Next, a reduced-pressure drying process for the substrate 9 using the reduced-pressure drying apparatus 1 will be described. Fig. 7 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. 7 are performed in the order shown.

When performing the reduced pressure drying process using the reduced pressure drying apparatus 1, for example, first, the substrate 9 is loaded into the chamber 10 (step S1). At this time, an undried coating film 90 is formed on the first surface F1 of the substrate 9. 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) loads the substrate 9 on a fork-shaped hand and loads the substrate 9 into the internal space 10s of the chamber 10 through the loading/unloading port 14 of the chamber 10. At this point, the support unit 20 is located, for example, in the lowered position H2. Note that the side straightening plate 51 may be configured to be movable so that it does not interfere with the transport robot. For example, the transport robot loads the substrate 9 on the support unit 20 while inserting the fork-shaped hand between the multiple support plates 21 of the support unit 20, and then retracts the fork to the outside of the chamber 10. Then, the gate unit 15 closes the loading/unloading port 14 under the control of the control unit 80. As described above, in step S1, a process of placing the substrate 9 on a plurality of support pins 22 arranged in the chamber 10 (also called a placing process) is performed.

Next, the reduced pressure drying apparatus 1 performs a cooling process (step S2). The cooling process is a process of cooling the cooling surface 40a. Specifically, the control unit 80 operates the cooling unit 40, which causes the cooling unit 40 to cool the cooling surface 40a and lower the temperature of the cooling surface 40a. The cooling unit 40 lowers the temperature of the cooling surface 40a to a target temperature. The target temperature is, for example, 5 degrees Celsius or higher and 15 degrees Celsius or lower. 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 prior to step S1.

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. 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).

Next, the reduced pressure drying apparatus 1 performs a first decompression process (corresponding to step S4: first process). The first decompression process is a process for lowering the air pressure in the chamber 10 to a first air pressure (hereinafter referred to as the first target air pressure). The first target air pressure is set lower than the standard atmospheric pressure, for example, 10 kPa or higher. Specifically, the control unit 80 lowers the air pressure in the chamber 10 by having the decompression mechanism 30 suck in 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 a smaller opening than during the second decompression process described below. This allows the air pressure in the chamber 10 to decrease at a slower rate during the first decompression process.

In step S3, for example, the control unit 80 may individually and appropriately control the open/closed state of each of the multiple individual valves Va, Vb, Vc, and Vd. This makes it possible to control the airflow within the chamber 10 so as to prevent uneven drying of the substrate 9.

Figures 8 and 9 are schematic diagrams showing an example of the state inside the chamber 10 during the first decompression process. Figure 8 shows the entire chamber 10, and Figure 9 shows an enlarged view of the cooling surface 40a and the vicinity of the substrate 9 inside the chamber 10.

As shown in FIG. 8, in the first decompression process, in the first state in which the support portion 20 is located at the raised position H1, the distance between the substrate 9 and the cooling surface 40a is very narrow. Therefore, the rate at which the air pressure in the upper space 10s1 decreases becomes slower, and the occurrence of bumping in the coating film 90 on the first surface F1 of the substrate 9 can be suppressed.

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 straightening plate 51. Therefore, the straightening function of the side straightening plate 51 hardly works on the upper space 10s1 between the substrate 9 and the cooling surface 40a. Therefore, the side straightening 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 straightening plate 51 and the side wall portion 12 of the chamber 10 and is exhausted from the chamber 10. In FIG. 8, this airflow is shown diagrammatically by dashed arrows.

The first decompression process reduces the air pressure in the chamber 10, so that the solvent in the coating film 90 on the first surface F1 of the substrate 9 evaporates. In FIG. 9, the flow of solvent vapor from the coating film 90 is shown by dashed arrows. In the first decompression process, the cooling unit 40 cools the cooling surface 40a, so that the solvent vapor from the coating film 90 is cooled and condensed on the cooling surface 40a. That is, as shown in FIG. 9, liquid solvent 91 adheres to the cooling surface 40a. In other words, the target temperature of the cooling surface 40a is set to a temperature at which the solvent vapor condenses when the air pressure in the chamber 10 is the first target air pressure. As a more specific example, the target temperature of the cooling surface 40a is set to a temperature at which the pressure becomes the first target air pressure on the vapor pressure curve of the solvent. As a result, the solvent 91 can be adhered almost uniformly to the area of the cooling surface 40a that faces the coating film 90. In this way, the solvent vapor in the upper space 10s1 condenses on the cooling surface 40a, decreasing the concentration of the solvent vapor in the upper space 10s1, and the concentration distribution of the solvent vapor when viewed from above becomes more uniform.

For comparison, a comparative structure in which a cooling unit 40 is not provided will be described. FIG. 10 is an enlarged view of the top plate 13 and substrate 9 of the chamber 10 in the comparative structure. In the example of FIG. 9, the lower surface 13a of the top plate 13 of the chamber 10 is not cooled by the cooling unit 40. The temperature of the lower surface 13a of the top plate 13 is, for example, approximately room temperature.

In the first decompression process, the gap between the substrate 9 and the lower surface 13a is narrow, so the solvent vapor from the coating film 90 immediately collides with the lower surface 13a of the top plate portion 13. For this reason, the solvent vapor is likely to remain in the central region of the upper space 10s1 that faces the central portion of the coating film 90. On the other hand, in the peripheral region of the upper space 10s1 that faces the peripheral portion of the coating film 90, the solvent vapor can flow out horizontally due to concentration diffusion. For this reason, the peripheral portion of the coating film 90 is more likely to evaporate than the central portion. In other words, uneven drying of the coating film 90 may occur.

Figure 11 is a diagram showing an example of the concentration distribution of solvent vapor in the upper space 10s1 in the comparative structure. Figure 11(a) shows the concentration distribution of solvent vapor in a top view, and Figure 11(b) shows the concentration distribution of solvent vapor in a side view. In Figure 11(a), the concentration distribution of solvent vapor is shown by contour lines T1 to T10. The smaller the number of the symbol of the contour lines T1 to T10, the higher the concentration. In other words, the contour line T1 shows the highest concentration between the contour lines T1 to T10. In Figure 11(b), the concentration distribution of solvent vapor is shown by contour lines T11 to T21. The smaller the number of the symbol of the contour lines T11 to T21, the higher the concentration. In other words, the contour line T11 shows the highest concentration between the contour lines T11 to T21.

As can be seen from FIG. 11(a), in the comparative structure, solvent vapor flows from the periphery of the coating film 90 to the outside. Also, as shown in FIG. 11(b), in the peripheral region 10r of the upper space 10s1 that faces the peripheral portion of the coating film 90, the concentration of solvent vapor decreases toward the outside of the coating film 90. For this reason, it can be seen that the peripheral portion of the coating film 90 is more likely to evaporate than the central portion.

Figure 12 is a diagram showing an example of the concentration distribution of the solvent vapor in the upper space 10s1 when the cooling unit 40 is cooling. Figure 12(a) shows the concentration distribution of the solvent vapor in a top view, and Figure 12(b) shows the concentration distribution of the solvent vapor in a side view. As can be seen from Figure 12(a), the solvent vapor does not flow outward from the periphery of the coating film 90 very much. This is because the solvent vapor from the coating film 90 is cooled and condensed on the cooling surface 40a. In other words, both the solvent vapor from the central part of the coating film 90 and the solvent vapor from the peripheral part flow upward with an ascending air current according to the temperature difference with the cooling surface 40a and condense on the cooling surface 40a (see also Figure 9). In this way, the solvent vapor from the peripheral part also condenses on the cooling surface 40a, so there is not much outward flow of the solvent vapor. In addition, the solvent vapor from the coating film 90 does not remain in the upper space 10s1 very much.

As shown in FIG. 12(b), even in the peripheral region 10r, the concentration of solvent vapor decreases with increasing distance from the coating film 90 in the vertical direction, but is almost uniform in the horizontal direction.

This reduces the difference between the amount of evaporation in the central portion and the amount of evaporation in the peripheral portion of the coating film 90, thereby suppressing the occurrence of uneven drying. In addition, the condensation of the solvent vapor on the cooling surface 40a reduces the concentration of the solvent vapor in the upper space 10s1, which can promote the evaporation of the coating film 90. This can also improve the throughput of the reduced pressure drying process.

Next, for example, when the air pressure inside the chamber 10 reaches the first target air 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.

Next, the reduced pressure drying apparatus 1 performs a second decompression process (corresponding to step S6: second process). The second decompression 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 lowers the pressure in the chamber 10 by having the decompression 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 during the first decompression process. The pressure in the chamber 10 is lowered to the second target pressure at a rate higher than that during the first decompression process. In the second decompression 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.

In step S6, for example, the control unit 80 may individually and appropriately control the open/closed state of each of the multiple individual valves Va, Vb, Vc, and Vd. This allows the airflow in the chamber 10 to be controlled so as to suppress uneven drying of the substrate 9.

Figure 13 is a schematic diagram showing an example of the state inside the chamber 10 during the second decompression process. As shown in Figure 13, in the second state in which the support part 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 less likely to stagnate. Because the upper space 10s1 is large, the air pressure inside the upper space 10s1 can be more appropriately and quickly reduced to the second target air pressure.

In addition, in the second state, the substrate 9 supported by the support portion 20 is surrounded by four side straightening plates 51. Therefore, the straightening function of the side straightening plates 51 acts on the upper space 10s1 between the substrate 9 and the cooling surface 40a. In other words, the side straightening plates 51 can suppress the concentration of airflow on the peripheral portion of the substrate 9. Therefore, the occurrence of uneven drying of the coating film 90 due to airflow can be further suppressed.

When the pressure in the chamber 10 reaches the second target pressure, the solvent in the coating film 90 boils and the coating film 90 dries at a higher speed. The pressure reduction 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 pressure reduction 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.

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 Figure 13, the flow of these solvent vapors is shown diagrammatically by dashed arrows.

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

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 air pressure in the chamber 10 to the second target air pressure or lower. This allows the decompression drying device 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.

When both the coating film 90 and the cooling surface 40a are sufficiently dry, 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 air pressure inside the chamber 10 to rise again to atmospheric pressure.

Finally, for example, the substrate 9 is removed from the chamber 10 (step S8). In step S8, for example, the gate unit 15 first opens the loading/unloading port 14 under the control of the control unit 80, and a transport robot (not shown) removes the dried substrate 9 placed on the support unit 20 to the outside of the chamber 10 via the loading/unloading port 14 of the chamber 10. This may complete the reduced pressure drying process for one substrate 9.

As described above, in this embodiment, the control unit 80 controls the first lifting unit 100 and the pressure reduction mechanism 30 so that the air pressure in the chamber 10 is a first air pressure in a first state in which the distance between the substrate 9 and the cooling surface 40a is a first distance, and then controls the first lifting unit 100 and the pressure reduction mechanism 30 so that the air pressure in the chamber 10 is a second air pressure in a second state in which the distance between the substrate 9 and the cooling surface 40a is a second distance.

Specifically, first, in the first decompression process, the cooling unit 40 cools the cooling surface 40a, and the first lifting unit 100 raises the support unit 20 to the raised position H1, and the decompression mechanism 30 lowers the air pressure in the chamber 10 to the first target air pressure. In the first decompression process, the support unit 20 is located at the raised position H1, so the distance between the substrate 9 and the cooling surface 40a is narrow. This makes it possible to suppress a sudden drop in air pressure in the upper space 10s1 between the substrate 9 and the cooling surface 40a, and to suppress the occurrence of bumping of the coating film 90.

In addition, in the first decompression process, the cooling unit 40 cools the cooling surface 40a. More specifically, the cooling unit 40 lowers the temperature of the cooling surface 40a to a target temperature at which the solvent vapor condenses under the first target atmospheric pressure. As a result, the solvent vapor from the coating film 90 on the substrate 9 condenses on the cooling surface 40a. This makes it possible to suppress the retention of solvent vapor in the upper space 10s1 (particularly the central region), and to suppress the occurrence of uneven drying of the coating film 90.

Meanwhile, in the second decompression process after the first decompression process, the decompression mechanism 30 reduces the air pressure inside the chamber 10 to a second target air pressure or lower while the first lifting unit 100 lowers the support unit 20 to the lowered position H2. Because the support unit 20 is located at the lowered position H2, the gap between the substrate 9 and the cooling surface 40a is wide. This allows the air pressure inside the chamber 10 to be reduced more appropriately and quickly. Therefore, the coating film 90 can be dried more appropriately and quickly. In addition, because the gap between the substrate 9 and the cooling surface 40a is wide in the second decompression process, solvent vapor is less likely to remain and uneven drying is less likely to occur.

In addition, in the second reduced pressure process, the temperature of the cooling surface 40a is such that the solvent evaporates under the second target pressure. Therefore, in the second reduced pressure process, not only the coating film 90 on the substrate 9 but also the cooling surface 40a can be dried. Therefore, there is no need to separately dry the cooling surface 40a before performing the reduced pressure drying process on the next substrate 9, and the reduced pressure drying process on the next substrate 9 can be performed quickly. This makes it possible to improve the throughput of the reduced pressure drying process on multiple substrates 9.

In addition, in the first embodiment, the ceiling surface of the chamber 10 corresponds to the cooling surface 40a. Therefore, if the cooling unit 40 is attached externally to the top surface of the chamber 10, the existing chamber 10 can be used as is.

In the first embodiment, the cooling member 41 cools the top plate 13, thereby cooling the cooling surface 40a, which is the lower surface of the top plate 13. Although the temperature distribution in the cooling member 41 when viewed from above may vary slightly depending on the extension shape of the refrigerant flow path 41a, the variation in temperature distribution is mitigated toward the cooling surface 40a due to heat transfer in the top plate 13. In other words, the temperature distribution on the cooling surface 40a of the top plate 13 can be made more uniform. Therefore, the solvent vapor from the coating film 90 on the first surface F1 of the substrate 9 can be more uniformly condensed on the cooling surface 40a. Therefore, the uniformity of the concentration distribution of the solvent vapor in the upper space 10s1 can be increased. This further suppresses the occurrence of drying unevenness.

In addition, in the first embodiment, the first lifting unit 100 that raises and lowers the support unit 20 is used to adjust the gap between the substrate 9 and the cooling surface 40a. Therefore, the existing first lifting unit 100 can be used as is.

<2. Second embodiment>
FIG. 14 is a diagram showing an example of a vertical cross section of the reduced pressure drying apparatus 1A according to the second embodiment. The reduced pressure drying apparatus 1A has the same configuration as the reduced pressure drying apparatus 1 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. 14, 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.

Figure 15 is a flow chart showing an example of the flow of the reduced pressure drying process according to the second embodiment. Here, for example, the processes from step S11 to step S19 in Figure 15 are performed in the order shown. The cooling member 41 is initially located at the cooling position H3.

The reduced pressure drying apparatus 1A first performs steps S11 to S15 in this order. Steps S11 to S15 are the same as steps S1 to S5, respectively. However, the cooling operation of the cooling surface 40a by the cooling unit 40 may essentially end at step S15.

After step S15, the reduced pressure drying apparatus 1A 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.

Next, the reduced pressure drying apparatus 1A performs steps S17 to S19. Steps S17 to S19 are the same as steps S6 to S8, respectively.

As described above, according to the second 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 1A can more reliably condense the solvent vapor on the cooling surface 40a in the first decompression process. Moreover, according to the second embodiment, in the second decompression process (step S17), the cooling member 41 ascends to the separated position H4. Therefore, in the second decompression process, the cooling operation on the cooling surface 40a can be substantially interrupted. As the cooling member 41 moves away from the cooling surface 40a, the temperature of the cooling surface 40a increases over time, and the evaporation of the solvent 91 attached to the cooling surface 40a can be promoted. Therefore, the reduced pressure drying apparatus 1A can more reliably dry the cooling surface 40a in the second decompression process.

<3. Third embodiment>
16 is a diagram illustrating an example of a vertical cross section of a reduced pressure drying apparatus 1B according to a third embodiment. The reduced pressure drying apparatus 1B has a similar configuration to the reduced pressure drying apparatus 1 except for the internal configuration of the cooling section 40.

As shown in FIG. 16, a part of the cooling section 40 of the reduced pressure drying apparatus 1B is embedded in the top plate 13 of the chamber 10. Here, the top plate 13 functions as the cooling member 41. The top plate 13 may be made of a material with high thermal conductivity (e.g., metal). In the example of FIG. 16, a refrigerant flow path 41a, which is a part of the cooling section 40, is formed inside the top plate 13. The refrigerant flow path 41a may meander inside the top plate 13 when viewed from above, or may extend in a spiral shape. In the example of FIG. 16, the inlet 41b and the outlet 41c of the refrigerant flow path 41a are formed on the upper surface of the top plate 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 13 of the chamber 10. In other words, the cooling surface 40a, which is the underside of the top plate 13, is cooled.

An example of the flow of the reduced pressure drying process using the reduced pressure drying apparatus 1B is similar to the reduced pressure drying process in the first embodiment. As a result, in the third embodiment as well, it is possible to improve the throughput of the reduced pressure drying process for multiple substrates 9 while suppressing the occurrence of uneven drying.

In addition, in the third embodiment, the top plate portion 13 functions as the cooling member 41. Therefore, the number of parts of the reduced pressure drying device 1B can be reduced, and the size and manufacturing costs of the reduced pressure drying device 1B 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.

The part of the cooling unit 40 embedded in the top plate 13 is a low-temperature part that absorbs heat from the top plate 13. For example, if the cooling unit 40 has a cooling element such as a Peltier element, the cooling element is embedded in the top plate 13.

<4. Fourth embodiment>
17 is a diagram illustrating an example of a vertical cross section of a reduced pressure drying apparatus 1C according to a fourth embodiment. The reduced pressure drying apparatus 1C has a similar configuration to the reduced pressure drying apparatus 1 except for the internal configuration of the cooling section 40.

As shown in FIG. 17, a part of the cooling section 40 of the reduced pressure drying apparatus 1C 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 with 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 fourth embodiment, the lower surface of the cooling member 41 corresponds to the cooling surface 40a.

In the example of FIG. 17, the first refrigerant pipe 42 and the second refrigerant pipe 43 pass through the top plate portion 13, and the refrigerant cooling source 44 is provided outside the chamber 10. The refrigerant cooling source 44 cools the refrigerant while circulating the refrigerant, thereby cooling the cooling member 41. In other words, the cooling surface 40a of the cooling member 41 is cooled.

17, the cooling member 41 has a size larger than the substrate 9 in top view. The cooling surface 40a of the cooling member 41 may have a rectangular shape similar to that of the substrate 9 in top view. In this case, the long side of the cooling surface 40a is longer than the long side of the substrate 9, and the short side of the cooling surface 40a is longer than the short side of the substrate 9. In this way, the cooling surface 40a can face the entire first surface F1 of the substrate 9 in the vertical direction. The cooling surface 40a may also have a square shape in top view. In this case, one side of the cooling surface 40a may be longer than the short side of the substrate 9. In this way, regardless of the orientation of the substrate 9 placed on the support part 20, the cooling surface 40a is larger than the substrate 9 in top view. Therefore, regardless of the orientation of the substrate 9, the cooling surface 40a can face the entire first surface F1 of the substrate 9.

An example of the flow of the reduced pressure drying process using the reduced pressure drying apparatus 1C is similar to the reduced pressure drying process in the first embodiment. As a result, in the fourth embodiment as well, it is possible to improve the throughput of the reduced pressure drying process for multiple substrates 9 while suppressing the occurrence of uneven drying.

Moreover, in the fourth embodiment, the cooling surface 40a is the underside of a 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. Also, because the cooling surface 40a is the underside 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.

<5. Fifth embodiment>
FIG. 18 is a diagram showing an example of a vertical cross section of a reduced pressure drying apparatus 1D according to the fifth embodiment. The reduced pressure drying apparatus 1D has a similar configuration to the reduced pressure drying apparatus 1C, except for the object to be raised and lowered by the first lifting section 100. As shown in FIG. 18, the first lifting section 100 lifts and lowers the cooling section 40. Specifically, the first lifting section 100 lifts 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. 18, 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.

As shown in FIG. 18, the support portion 20 is located at the lowered position H2 referred to in the first to fourth embodiments. In other words, the substrate 9 supported by the support portion 20 is located lower than the upper end of the side straightening plates 51 and is surrounded by the four side straightening plates 51. In the fifth embodiment, the substrate 9 is surrounded by the four side straightening plates 51 in both the first state in which the distance between the substrate 9 and the cooling surface 40a is the first distance, and the second state in which the distance between the substrate 9 and the cooling surface 40a is the second distance.

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 air straightening plate 51. In other words, the cooling member 41 has a size smaller than the space surrounded by the four side air straightening plates 51 when viewed from above.

The raised position H11 is a position where the cooling surface 40a of the cooling member 41 is above the upper end of the side straightening plate 51. When the cooling member 41 is in the raised position H11, the distance between the cooling surface 40a and the upper end of the side straightening plate 51 may be, for example, at least twice the first distance, or may be at least five times the first distance. This makes it easier for gas directly above the substrate 9 to flow 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.

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 relative 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.

An example of the flow of the reduced pressure drying process using the reduced pressure drying device 1D is similar to the reduced pressure drying process in the first embodiment. However, in the first gap adjustment process (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 (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. As a result, even in the fifth embodiment, it is possible to improve the throughput of the reduced pressure drying process for multiple substrates 9 while suppressing the occurrence of uneven drying.

In addition, in the fifth embodiment, the cooling member 41 is separate from the chamber 10. Therefore, similar to the fourth embodiment, the selectivity of the material of the cooling member 41 can be improved. Also, since the cooling surface 40a is the lower surface of the cooling member 41, similar to the fourth embodiment, the cooling unit 40 can cool the cooling surface 40a with higher efficiency.

In addition, in the fifth 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 straightening plates 51. Therefore, even in the first decompression process (step S4), the straightening function of the four side straightening plates 51 also 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.

6. Modifications
The present disclosure is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the gist of the present disclosure.

In the above embodiment, the first lifting unit 100 lifts and lowers the support unit 20 or the cooling unit 40, but 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 that is wider than the first distance.

In the above embodiment, for example, the chamber 10 has four exhaust ports 16a, 16b, 16c, and 16d, but this is not limited to this. For example, the number of exhaust ports that the chamber 10 has may be any of one to three and five or more. Also, for example, the individual valves Va, Vb, Vc, and Vd may not be required.

In the above embodiment, the reduced pressure drying apparatus 1, 1A to 1D dries the coating film 90 on the substrate 9 by reducing pressure, but this is not limited to the above. For example, the reduced pressure drying apparatus 1, 1A to 1D may dry the coating film 90 on the substrate 9 by reducing pressure and heating.

In the above embodiment, the side wall 12 of the chamber 10 is provided with the entrance/exit 14 for the substrate 9, but this is not limited thereto. For example, a structure may be adopted in which the four side wall parts 12 and the top plate part 13 of the chamber 10 form an integrated lid part, and the lid part can be separated from the bottom plate part 11 and retreated upward. In this case, for example, the lid part may be moved up and down by the opening/closing drive part 16 or the like. The chamber 10 can be selectively set to a state in which the lid part contacts the bottom plate part 11 via a sealing material such as an O-ring to seal the internal space 10s (sealed state), and a state in which the lid part separates upward from the bottom plate part 11 to open the internal space 10s (open state). Here, if 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.

In the above embodiment, for example, the support portion 20 may have various forms. For example, the multiple support plates 21 may be one integral support plate 21.

In the above embodiment, for example, the bottom baffle plate 50 may be omitted, and the side baffle plate 51 may be omitted.

In the above embodiment, for example, various operations in the reduced pressure drying device 1 may be started or ended in response to, for example, a user's action on the input unit 804 or a signal input from an external device to the communication unit 806.

In the above embodiment, for example, at least a portion of the functional configuration realized in the control unit 80 may be configured with hardware such as a dedicated electronic circuit.

It goes without saying that all or part of the components of the above embodiment and various modified examples can be combined as appropriate and consistent.

Reference Signs List 1, 1A to 1D reduced pressure drying apparatus 10 chamber 13 top plate section 100 first lift section 20 support section 30 reduced pressure mechanism 40 cooling section 40a cooling surface 45 second lift section 50 bottom surface current plate 51 side surface current plate 80 control section 9 substrate 90 coating film F1 upper surface (first surface)
S4, S14 First process (step)
S6, S17 Second process (step)

Claims (12)

A reduced pressure drying apparatus for drying a coating film applied on an upper surface of a substrate, comprising:
a chamber for housing the substrate;
a support for supporting the substrate within the chamber;
a cooling part that cools a cooling surface that faces the upper surface of the substrate supported by the support part;
a first lifting unit that lifts and lowers at least one of the support unit and the cooling surface between a first state in which a distance between the substrate supported by the support unit and the cooling surface is a first distance and a second state in which a distance between the substrate supported by the support unit and the cooling surface is a second distance that is wider than the first distance;
a pressure reducing mechanism that sucks gas from within the chamber to reduce the air pressure within the chamber;
and a control unit that controls the first lifting unit and the decompression mechanism so that the air pressure in the chamber is set to a first air pressure in the first state, and then, in the second state, the air pressure in the chamber is set to a second air pressure lower than the first air pressure. The reduced pressure drying apparatus according to claim 1,
the control unit controls the cooling unit to cool the cooling surface to a temperature below a temperature at which the pressure becomes the first atmospheric pressure on a vapor pressure curve of the solvent on the substrate in the first state, and to a temperature above a temperature at which the pressure becomes the second atmospheric pressure on the vapor pressure curve in the second state. The reduced pressure drying apparatus according to claim 1 or 2,
The control unit is a reduced pressure drying apparatus in which, in the first state, the air pressure in the chamber is reduced to the first air pressure, thereby evaporating the solvent of the coating film on the substrate while condensing the solvent vapor on the cooling surface, and in the second state, the control unit is reduced to the second air pressure, thereby evaporating both the solvent of the coating film on the substrate and the solvent on the cooling surface, thereby drying the coating film and the cooling surface. The reduced pressure drying apparatus according to claim 1 or 2 ,
the cooling surface is a ceiling surface of the chamber;
The first lifting unit lifts and lowers the support unit. The reduced pressure drying apparatus according to claim 4 ,
The cooling unit is attached to an upper surface of a top plate of the chamber and cools the top plate to cool the cooling surface, which is the underside of the top plate. The reduced pressure drying apparatus according to claim 5 ,
The reduced pressure drying apparatus further includes a second lifting unit that raises and lowers the cooling unit between a cooling position in contact with the upper surface of the top plate unit and a spaced position away from the top plate unit. The reduced pressure drying apparatus according to claim 4 ,
At least a portion of the cooling unit is embedded in a top plate portion of the chamber. The reduced pressure drying apparatus according to claim 1 or 2 ,
The cooling section is a reduced pressure drying apparatus, the cooling section being provided within the chamber and including a cooling member having the cooling surface as a lower surface. The reduced pressure drying apparatus according to claim 8,
The first lifting unit lifts and lowers the cooling member. The reduced pressure drying apparatus according to claim 9 ,
a side baffle plate surrounding the substrate supported by the support portion;
a bottom surface current plate facing a lower surface of the substrate supported by the support portion ,
A reduced-pressure drying apparatus, wherein in both the first state and the second state, the substrate supported by the support portion is surrounded by the side baffle plate. A reduced pressure drying method for drying a coating film applied on an upper surface of a substrate, comprising the steps of:
a first step of cooling a cooling surface facing the upper surface of the substrate supported by a support part in a chamber, and reducing the air pressure in the chamber to a first air pressure while a distance between the substrate and the cooling surface is a first distance, thereby evaporating a solvent in the coating film on the substrate and condensing the solvent vapor on the cooling surface;
a second step of, after the first step, reducing the air pressure in the chamber to a second atmospheric pressure lower than the first atmospheric pressure while a gap between the substrate and the cooling surface is a second gap wider than the first gap, thereby evaporating both the solvent of the coating film on the substrate and the solvent of the cooling surface to dry the coating film and the cooling surface. The reduced pressure drying method according to claim 11 ,
In the first step, a cooling unit is lowered to a cooling position where the cooling unit contacts an upper surface of a top plate of the chamber, thereby cooling the cooling surface, which is the lower surface of the top plate;
A reduced pressure drying method, wherein in the second step, the cooling section is raised to a separate position away from the top plate section of the chamber.

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