Vacuum drying device and vacuum drying method

Abstract

The present invention provides a reduced-pressure drying apparatus and a reduced-pressure drying method that can avoid excessively reducing production efficiency and avoid excessive accumulation of liquid solvent on the cooling surface in the cooling unit. The reduced-pressure drying apparatus (1) is used to dry a coating film (90) applied to the upper surface of a substrate (9). A chamber (10) houses the substrate. A support portion (20) supports the substrate within the chamber (10). A cooling unit (40) cools a cooling surface (40a) facing the upper surface of the substrate supported by the support portion (20). A decompression mechanism (30) sucks gas from the chamber to reduce the pressure within the chamber (10). A gas supply mechanism (60) supplies gas into the chamber (10) to increase the pressure within the chamber (10). A control unit (80) controls the gas supply mechanism (60) such that, after supplying a predetermined amount of gas from the gas supply mechanism (60) into the chamber (10) in a decompressed state, an amount of gas that makes the pressure within the chamber (10) become atmospheric pressure is supplied from the gas supply mechanism (60).

Description

Technical Field

[0001] The present invention relates to a reduced-pressure drying device and a reduced-pressure drying method. Background Art

[0002] Conventionally, a reduced-pressure drying device for reducing the pressure of a coating film such as a photoresist applied on various substrates has been known. Various substrates include, for example, various substrates such as glass substrates, ceramic substrates, semiconductor wafers, electronic device substrates, or printing plates for printing, which are used for forming various devices. Various devices include, for example, semiconductor devices, display panels, solar cell panels, magnetic disks, or optical disks. Display panels include, for example, liquid crystal display panels, organic electroluminescence (EL) display panels, plasma display panels, or field emission displays.

[0003] When drying a coating film using a reduced-pressure drying device, for example, in a state where a plurality of pins support a substrate in a chamber, the chamber is evacuated through an exhaust port at the bottom of the chamber using a vacuum pump. By this evacuation, the pressure in the chamber is reduced. If the pressure in the chamber is reduced, the solvent of the coating film evaporates, so that the coating film can be dried. And, for example, when the degree of vacuum reaches a specified value, the evacuation from the chamber is stopped, and the pressure in the chamber is restored to atmospheric pressure by supplying gas into the chamber. The gas is, for example, an inert gas such as nitrogen or air.

[0004] However, in a reduced-pressure drying device, if the pressure in the chamber is rapidly reduced at the initial stage of decompression, the coating film on the substrate may boil violently. If violent boiling occurs, it may cause, for example, a deviation in the film thickness of the coating film.

[0005] The reduced-pressure drying device described in Patent Document 1 can suppress the occurrence of such violent boiling. In the reduced-pressure drying device described in Patent Document 1, a lifting part for lifting and lowering the support pins that support the substrate is provided. At the initial stage of decompression, the lifting part raises the support pins, thereby reducing the distance between the substrate and the top surface of the chamber. Thereby, the rate of decrease in the pressure between the substrate and the top surface can be made smaller, and the occurrence of violent boiling can be suppressed.

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022-086766

[0007] However, when the distance between the substrate and the top surface is reduced, the solvent vapor from the coating film on the substrate stays in the space between the substrate and the top surface. In particular, the solvent vapor from the vicinity of the center of the coating film is likely to stay. That is, although the solvent vapor from the vicinity of the periphery of the coating film can flow outward in the horizontal direction by concentration diffusion, in the vicinity of the center of the coating film, since the concentration gradient is small, the solvent vapor stays directly. Therefore, compared with the central part, the solvent of the coating film is more likely to evaporate at the peripheral part. That is, it causes non-uniform drying of the coating film. Non-uniform drying may cause, for example, a problem of deviation in the film thickness of the dried coating film. Summary of the Invention

[0008] In order to solve the above problems, the inventor of the present invention studied the technique of cooling the top surface to make it a cooling surface. According to this technique, uneven drying can be suppressed by the action of the liquid solvent condensed on the cooling surface. On the other hand, the inventor found that if only the top surface is used as the cooling surface, a new problem will occur, that is, the liquid solvent will accumulate excessively on the cooling surface. In particular, in industrial applications, usually, it is necessary to repeatedly operate the vacuum drying device without a long time interval. As a result, even if the accumulation amount in one operation is small, with the repetition of the operation, the liquid solvent is likely to accumulate excessively on the cooling surface. The excessively accumulated liquid solvent will have an adverse effect during the implementation of vacuum drying. For example, if it drips onto the substrate, it will damage the quality of the product using the substrate. Although the excessively accumulated liquid solvent can be removed by sufficiently extending the drying time under reduced pressure conditions, this is likely to cause an excessive reduction in production efficiency.

[0009] The present invention is proposed in view of the above problems, and its object is to provide a technique that can avoid excessive reduction in production efficiency and excessive accumulation of liquid solvent on the cooling surface of the cooling part.

[0010]

Means for Solving the Problem

[0011] The first aspect is a vacuum drying device for drying a coating film applied to the upper surface of a substrate, comprising: a chamber for accommodating the substrate; a support part for supporting the substrate in the chamber; a cooling part for cooling a cooling surface opposite to the upper surface of the substrate supported by the support part; a decompression mechanism for sucking gas from the chamber to reduce the pressure in the chamber; a gas supply mechanism for supplying gas to the chamber to increase the pressure in the chamber; and a control part for controlling the gas supply mechanism so that after supplying a specified amount of gas from the gas supply mechanism to the chamber in a decompressed state, the gas supply mechanism supplies an amount of gas that makes the pressure in the chamber become atmospheric pressure.

[0012] The second aspect is the vacuum drying device according to the first aspect, wherein the gas supply mechanism includes: a gas supply source; a first buffer part located between the chamber and the gas supply source; a first gas supply valve located between the chamber and the first buffer part; and a second gas supply valve located between the first buffer part and the gas supply source. In order to supply the specified amount of gas, the control part controls the gas supply mechanism so that the second gas supply valve remains closed and the first gas supply valve is switched from the closed state to the open state.

[0013] The third mode is a reduced-pressure drying apparatus according to the second mode, wherein the gas supply mechanism includes: a second buffer portion located between the second gas supply valve and the gas supply source; and a third gas supply valve located between the second buffer portion and the gas supply source. In order to supply the specified amount of gas, after the control unit controls the gas supply mechanism to keep the second gas supply valve closed and switch the first gas supply valve from the closed state to the open state, the control unit controls the gas supply mechanism to switch the second gas supply valve from the closed state to the open state.

[0014] The fourth mode is a reduced-pressure drying apparatus according to any one of the first to third modes, wherein the pressure reducing mechanism includes: a vacuum pump; and at least one vacuum valve located between the chamber and the vacuum pump. When the specified amount of gas is supplied, the control unit controls at least one of the vacuum valves so that the vacuum pump evacuates the chamber.

[0015] The fifth mode is a reduced-pressure drying apparatus according to any one of the first to third modes, wherein the pressure reducing mechanism includes: a vacuum pump; and at least one vacuum valve located between the chamber and the vacuum pump. When the specified amount of gas is supplied, the control unit controls at least one of the vacuum valves to disconnect between the vacuum pump and the chamber.

[0016] The sixth mode is a reduced-pressure drying apparatus according to the fifth mode, wherein after the specified amount of gas is supplied and before the amount of gas that makes the pressure in the chamber become atmospheric pressure is supplied from the gas supply mechanism, the control unit controls at least one of the vacuum valves so that the vacuum pump evacuates the chamber.

[0017] The seventh mode is a reduced-pressure drying method for drying a coating film applied to the upper surface of a substrate, which includes: a first step of reducing the pressure in the chamber by sucking gas from the chamber while cooling a cooling surface that faces the upper surface of the substrate supported by a support portion in the chamber at an interval, causing the solvent to evaporate from the coating film on the substrate and condensing on the cooling surface; a second step of increasing the pressure in the chamber by supplying a specified amount of gas to the chamber after the first step, causing the solvent on the cooling surface to evaporate to dry the cooling surface; and a third step of supplying an amount of gas that makes the pressure in the chamber become atmospheric pressure after the second step.

[0018]

Invention Effects

[0019] According to the above methods, first, before supplying an amount of gas that can make the pressure in the chamber become atmospheric pressure, gas is supplied to the chamber in a decompressed state. Thereby, the evaporation of the solvent condensed on the cooling surface of the cooling unit can be promoted. Therefore, excessive accumulation of the liquid solvent on the cooling surface of the cooling unit can be avoided. Second, the amount of the supplied gas is set to a specified amount. Thereby, the amount of the supplied gas can be controlled to a sufficient amount required to promote the above evaporation. Therefore, excessive reduction in production efficiency due to an excessive amount of the supplied gas can be avoided. In summary, both excessive reduction in production efficiency and excessive accumulation of the liquid solvent on the cooling surface of the cooling unit can be avoided. Description of the Drawings

[0020] Figure 1 is a diagram schematically showing an example of a longitudinal section of the decompression drying apparatus according to the first embodiment.

[0021] Figure 2 is a diagram schematically showing an example of a cross section of the decompression drying apparatus according to the first embodiment.

[0022] Figure 3 is a diagram showing an example of a longitudinal section of the decompression drying apparatus according to the first embodiment.

[0023] Figure 4 is a perspective view showing an example of a substrate.

[0024] Figure 5 is a diagram showing an example of a longitudinal section of a part of the substrate.

[0025] Figure 6 is a block diagram conceptually showing the functions implemented by the control unit.

[0026] Figure 7 is a flowchart showing an example of the process of the decompression drying method according to the first embodiment.

[0027] Figure 8 is a diagram schematically showing an example of the state in the chamber during the first decompression process.

[0028] Figure 9 is a diagram magnifying and showing the cooling surface and the vicinity of the substrate in the chamber during the first decompression process.

[0029] Figure 10 is a diagram magnifying and showing the top plate portion of the chamber and the substrate of the comparative structure.

[0030] Figure 11 is a diagram showing an example of the concentration distribution of the solvent vapor in the upper space in the comparative structure.

[0031] Figure 12It is a diagram showing an example of the concentration distribution of solvent vapor in the upper space in a state where the cooling section performs cooling.

[0032] Figure 13 It is a diagram showing an example of the state in the chamber during the second pressure reduction process schematically.

[0033] Figure 14 It is a graph showing the change of the chamber pressure over time during the pressure reduction drying of the first embodiment as an example.

[0034] Figure 15 It is a graph showing the change of the chamber pressure over time during the pressure reduction drying of the comparative example as an example.

[0035] Figure 16 It is a graph showing the change of the chamber pressure over time during the pressure reduction drying of the second embodiment as an example.

[0036] Figure 17 It is a diagram showing an example of the longitudinal section of the pressure reduction drying apparatus of the third embodiment schematically.

[0037] Figure 18 It is a graph showing the change of the chamber pressure over time during the pressure reduction drying of the third embodiment as an example.

[0038] Figure 19 It is a diagram showing an example of the longitudinal section of the pressure reduction drying apparatus of the fourth embodiment schematically.

[0039] Figure 20 It is a diagram showing an example of the longitudinal section of the pressure reduction drying apparatus of the fifth embodiment schematically.

[0040] Figure 21 It is a diagram showing an example of the longitudinal section of the pressure reduction drying apparatus of the sixth embodiment schematically.

[0041] Figure 22 It is a diagram showing an example of the longitudinal section of the pressure reduction drying apparatus of the seventh embodiment schematically. Detailed Embodiment

[0042] Hereinafter, an embodiment and various modification examples of the present invention will be described with reference to the accompanying drawings. The same reference numerals are given to parts having the same structure and function in the drawings, and repeated descriptions will be omitted in the following description. The drawings are schematically shown and do not accurately represent the dimensions and positional relationships of various structures in each drawing. In addition, in this specification, the downward direction is the direction of gravity, and the upward direction is the direction opposite to the direction of gravity. The upward direction and the downward direction are also collectively referred to as the up-and-down direction. The top view represents the planar layout. The planar layout of some components is a two-dimensional layout obtained by projecting the component onto a plane. This plane can be a plane perpendicular to the up-and-down direction.

[0043] <1. First Embodiment>

[0044] Figure 1 is a diagram schematically showing an example of a longitudinal section of the reduced-pressure drying apparatus 1 of the first embodiment. Figure 2 is a diagram schematically showing an example of a cross section of the reduced-pressure drying apparatus 1 of the first embodiment. Figure 3 is a diagram schematically showing an example of a longitudinal section of the reduced-pressure drying apparatus 1 of the first embodiment. Figure 1 The longitudinal section of Figure 3 The longitudinal sections of show the structure of the reduced-pressure drying apparatus 1 when viewed from directions that differ by approximately 90 degrees, respectively. In Figure 3 in order to avoid complication of the drawings, the related structures of the reduced-pressure mechanism 30, the air supply mechanism 60, the pressure gauge 70, and the control unit 80, which will be described later, are omitted.

[0045] The reduced-pressure drying apparatus 1 is an apparatus for drying a coating film 90 (see Figure 5 ) formed on the upper surface of the substrate 9.

[0046] The substrate 9 is, 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 Figure 4 and Figure 5 ) as a first main surface and a second surface F2 (see Figure 5 ) opposite to the first surface F1 as a second main surface. For example, in the reduced-pressure drying apparatus 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 the substrate 9 is a rectangular glass substrate is appropriately given for illustration. For example, by previously coating a treatment liquid containing an organic material and a solvent, the coating film 90 is partially formed on the first surface F1 of the substrate 9. The coating of the treatment liquid is performed, for example, by a slit coater or an inkjet device. The treatment liquid is, for example, a coating liquid such as a liquid containing a polyimide precursor and a solvent (also referred to as a PI liquid) or a resist liquid. The polyimide precursor is, for example, polyamide acid. The solvent is, for example, NMP (N-methyl-2-pyrrolidone). In addition, for example, in the case where the reduced-pressure drying apparatus 1 is used in the manufacturing process of an organic EL display, a method of forming a hole injection layer, a hole transport layer, or a light-emitting layer of an organic EL display panel by drying the coating film 90 with the reduced-pressure drying apparatus 1 may also be employed.

[0047] Figure 4 is a perspective view showing an example of the substrate 9. Figure 5 is a diagram schematically showing an example of a longitudinal section of a part of the substrate 9. As shown in Figure 4As shown, the substrate 9 is, for example, rectangular with different horizontal and vertical lengths when viewed from above. A plurality of regions (which can be referred to as formed regions or coating regions) A1 for forming devices and the like are arranged on the substrate 9. In Figure 4 In the example of, when viewed from above, four rectangular coating regions A1 are arranged in a two-row and two-column matrix on the substrate 9. However, the shape, number, and arrangement of the coating regions A1 are not limited to this example. In the coating process before the reduced-pressure drying device 1 performs the reduced-pressure drying process, a coating film 90 is formed in a desired pattern on the upper surface of each coating region A1 by a slit coater or an inkjet device or the like. The desired pattern is, for example, a circuit pattern. In addition, in Figure 4 , the coating film 90 is shown without considering the pattern. If considering without excluding the pattern, as shown in Figure 5 , the first surface F1, which is the upper surface of each coating region A1, may have a region (also referred to as a covered region) A3 covered by the coating film 90 and an exposed region (also referred to as an exposed area) A4 not covered by the coating film 90. In addition, the region around the coating region A1 in the substrate 9 and the region between adjacent coating regions A1 constitute a region (also referred to as a non-coating region) A2 where the coating film 90 is not formed on the first surface F1, which is the upper surface. The non-coating region A2 is also an exposed region (exposed area) A4 not covered by the coating film 90.

[0048] <1-1. Structural Outline of Reduced-Pressure Drying Device>

[0049] Next, an overview of the structure of the reduced-pressure drying device 1 will be given. As shown in Figure 1 and Figure 2 , the reduced-pressure drying device 1 includes a chamber 10, a support portion 20, a reduced-pressure mechanism 30, a cooling portion 40, a gas supply mechanism 60, and a control portion 80.

[0050] The chamber 10 is a portion for accommodating the substrate 9. The support portion 20 is provided in the chamber 10 to support the substrate 9 in a horizontal posture. Here, the so-called horizontal posture means that the thickness direction of the substrate 9 is along the up-and-down direction.

[0051] The reduced-pressure mechanism 30 sucks the gas in the chamber 10 and discharges the gas to the outside of the chamber 10. By this suction, the pressure in the chamber 10 is reduced. By reducing the pressure in the chamber 10, the solvent of the coating film 90 on the first surface F1 of the substrate 9 evaporates, and the coating film 90 is dried.

[0052] The cooling portion 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 portion 20 in the up-and-down direction. In Figure 1In the example, the cooling surface 40a corresponds to the top surface of the chamber 10. When viewed from above, the size of the cooling surface 40a is larger than that of the substrate 9. That is to say, the cooling surface 40a can have a size such that it can oppose the entire surface of the first surface F1 of the substrate 9. The cooling surface 40a is, for example, a horizontal flat surface. The cooling unit 40 cools the cooling surface 40a, thereby being able to lower the temperature of the cooling surface 40a.

[0053] The vapor of the solvent evaporated from the coating film 90 on the first surface F1 of the substrate 9 (hereinafter referred to as solvent vapor) can be cooled and condensed on the cooling surface 40a. Therefore, the liquid solvent 91 (see Figure 8 described later) can adhere to the cooling surface 40a. Through this condensation, as will be described in detail later, it is possible to suppress uneven drying of the coating film 90. In addition, by further reducing the pressure inside the chamber 10, it is also possible to promote the evaporation of the solvent 91 adhering to the cooling surface 40a. This condensation and evaporation will also be described in detail later.

[0054] The gas supply mechanism 60 supplies gas into the chamber 10. Thereby, it is possible to increase the pressure inside the chamber 10. The details will be described later. The gas supply mechanism 60 can increase the pressure to a value less than atmospheric pressure, and can also increase it to atmospheric pressure.

[0055] In addition, in Figure 1 the example, the vacuum drying apparatus 1 further includes a first lifting unit 100. 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 the raised position H1 and the lowered position H2. The raised position H1 is the position of the support unit 20 when the interval between the substrate 9 supported by the support unit 20 and the cooling surface 40a is the first interval. In Figure 1 the example, the support unit 20 and the substrate 9 located at the raised position H1 are shown by phantom lines. The lowered position H2 is the position of the support unit 20 when the interval between the substrate 9 supported by the support unit 20 and the cooling surface 40a is a second interval wider than the first interval. That is to say, the first lifting unit 100 lifts and lowers the support unit 20 between a first state and a second state. In the first state, the interval between the substrate 9 and the cooling surface 40a is the first interval, and in the second state, the interval between the substrate 9 and the cooling surface 40a is the second interval. The first interval is, for example, less than or equal to 10 mm. As a more specific example, the first interval is about 5 mm. The second interval can be, for example, more than 5 times the first interval, or more than 10 times. If specific examples of the values are described, the second interval is, for example, greater than or equal to 50 mm. As a more specific example, the second interval is about 80 mm.

[0056] As will be described in detail later, at the initial stage of decompression, the first elevating unit 100 positions the support unit 20 at the raised position H1. Then, the first elevating unit 100 lowers the support unit 20 to the lowered position H2. The technical significance thereof will be described in detail later.

[0057] In addition, in Figure 1 and Figure 2 example, the decompression drying apparatus 1 further includes a bottom surface rectifying plate 50, a side surface rectifying plate 51, and a pressure gauge 70. The bottom surface rectifying plate 50 and the side surface rectifying plate 51 are provided in the chamber 10 to adjust the air flow in the chamber 10. The pressure gauge 70 measures the pressure in the chamber 10 and outputs an electrical signal representing the measurement result to the control unit 80. The control unit 80 controls various structures of the above-described decompression drying apparatus 1.

[0058] Next, a detailed example of each structure of the decompression drying apparatus 1 will be described.

[0059] <1-1-1. Chamber 10>

[0060] The chamber 10 is a pressure-resistant container having an internal space 10s for accommodating the substrate 9. The chamber 10 is fixed, for example, to a device stand (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, the four end edges of the bottom plate portion 11 and the four end edges of the top plate portion 13 in the vertical direction. For example, an inlet / outlet 14 and a gate portion (also referred to as a gate valve) 15 for opening and closing the inlet / outlet 14 are provided on one of the four side wall portions 12. The gate portion 15 is connected or linked to an opening / closing drive unit 16, for example. In Figure 3 order to avoid complication of the drawings, the opening / closing drive unit 16 is conceptually shown. For example, a drive device such as a cylinder is applicable to the opening / closing drive unit 16. Here, for example, by the operation of the opening / closing drive unit 16, the gate portion 15 can move between a position where the inlet / outlet 14 is closed (also referred to as a closed position) and a position where the inlet / outlet 14 is opened (also referred to as an open position).

[0061] 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 inlet / outlet 14.

[0062] <1-1-2. Support unit 20>

[0063] 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 has, for example, a plurality of support plates 21 and a plurality of support pins 22. The plurality of support plates 21 are arranged at intervals in the horizontal direction, for example. A plurality of support pins 22 are erected on the upper surface of each support plate 21. When viewed from above, the plurality of support pins 22 are two-dimensionally and dispersedly arranged. The plurality of support plates 21 are the parts constituting the base of the support portion 20. The substrate 9 is disposed above the plurality of support plates 21, and the upper end portions of the plurality of support pins 22 are in contact with the second surface F2 which is the lower surface of the substrate 9, whereby the substrate 9 is supported in a horizontal posture.

[0064] <1-1-3. Pressure reducing mechanism 30>

[0065] As Figure 1 and Figure 2 shown, four exhaust ports 16a, 16b, 16c, and 16d are provided, for example, in a portion of the bottom plate portion 11 of the chamber 10 that faces the substrate 9 in the vertical direction. The pressure reducing mechanism 30 has an exhaust pipe 31, a vacuum pump 32, and at least one vacuum valve between the chamber 10 and the vacuum pump 32. In Figure 1 the example, as the at least one vacuum valve, four independent valves Va, Vb, Vc, and Vd and a main valve Vm are provided. The exhaust pipe 31 has, for example, four independent pipes 31a, 31b, 31c, and 31d and one main pipe 31e. For example, one end of the independent pipe 31a is connected to the exhaust port 16a, one end of the independent pipe 31b is connected to the exhaust port 16b, one end of the independent pipe 31c is connected to the exhaust port 16c, and one end of the independent pipe 31d is connected to the exhaust port 16d. For example, the other ends of the four independent pipes 31a, 31b, 31c, and 31d converge and are connected to one end of the main pipe 31e. For example, the other end of the main pipe 31e is connected to the vacuum pump 32. For example, the independent valve Va is provided in the path of the independent pipe 31a, the independent valve Vb is provided in the path of the independent pipe 31b, the independent valve Vc is provided in the path of the independent pipe 31c, and the independent valve Vd is provided in the path of the independent pipe 31d. For example, the main valve Vm is provided in the path of the main pipe 31e.

[0066] Here, for example, in a state where the carry-in outlet 14 is closed by the shutter portion 15, if at least one of the four independent valves Va, Vb, Vc, Vd and one main valve Vm are set to an open state and the vacuum pump 32 is started, the gas in the chamber 10 is discharged to the outside of the chamber 10 via the exhaust pipe 31. Thus, for example, the pressure in the internal space 10s of the chamber 10 can be reduced. Thereby, the chamber 10 is set to a reduced-pressure state. The four independent valves Va, Vb, Vc, Vd are, for example, valves for individually adjusting the exhaust volume (suction flow rate) of the four exhaust ports 16a, 16b, 16c, 16d. Each of the four independent valves Va, Vb, Vc, Vd is, for example, a valve (also called an on-off valve) that switches between an open state and a closed state according to an instruction from the control unit 80. The main valve Vm is, for example, a valve for adjusting the total exhaust volume of the four exhaust ports 16a, 16b, 16c, 16d. The main valve Vm is, for example, a valve (also called an opening-degree control valve) that can adjust the opening degree according to an instruction from the control unit 80. In the present first embodiment, as will be described later, when the gas supply mechanism 60 supplies a predetermined amount of gas into the chamber 10, the independent valves Va to Vd and the main valve Vm are controlled by the control unit 80 so that the vacuum pump 32 exhausts the chamber 10.

[0067] <1-1-4. First lifting unit 100>

[0068] In the first embodiment, the first lifting unit 100 raises and lowers the support portion 20 within the chamber 10. In other words, the first lifting unit 100 has a mechanism (also called a lifting mechanism) capable of raising and lowering the support portion 20. In Figure 1 order to avoid complication of the drawings, the first lifting unit 100 is conceptually shown. The first lifting unit 100 employs, for example, a driving device such as a linear motor or a cylinder. As Figure 3As shown, the first lifting part 100 has, for example, a main body part 100a and a moving part 100b. The main body part 100a is fixed, for example, outside the chamber 10 on a device rack (not shown). The moving part 100b can move relative to the main body part 100a in the vertical direction, for example. The moving part 100b is, for example, a rod-shaped member or the like. The moving part 100b exists in a state of passing through a through-hole 11h in the bottom plate part 11 of the chamber 10, for example. And, 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 support part 20 has a plurality of support plates 21, the moving part 100b has: rod-shaped parts (also called rod parts) respectively fixed on the respective support plates 21 and passing through the through-hole 11h of the bottom plate part 11; a part (also called a connecting part) connecting the plurality of rod parts; and a part (also called a sliding part) connected to the connecting part and slidably supported by the main body part 100a. The first lifting part 100 raises and lowers the support part 20, so that the substrate 9 supported by the support part 20 also moves up and down.

[0069] <1-1-5. Cooling part 40>

[0070] Although the specific structure of the cooling part 40 is not particularly limited, in Figure 1 the example, the cooling part 40 includes a cooling member 41, a first refrigerant pipe 42, a second refrigerant pipe 43, and a refrigerant cooling source 44. In addition, in Figure 3 for the sake of simplicity, the structure of the cooling part 40 is shown to avoid complicating the drawings. The shape of the cooling member 41 is plate-shaped. In this case, the cooling member 41 can also be called a cooling plate. The cooling member 41 is mounted on the upper surface of the top plate part 13 with its thickness direction in the vertical direction. When viewed from above, the cooling member 41 is, for example, rectangular. The lower surface of the cooling member 41 is preferably in close contact with the upper surface of the top plate part 13. The cooling member 41 can be formed of a material with high thermal conductivity (for example, metal or the like).

[0071] In Figure 1 the example, a refrigerant flow path 41a is formed inside the cooling member 41. The refrigerant flow path 41a can extend in a meandering shape or a spiral shape when viewed from above, for example. In Figure 1 the example, an inlet 41b and an outlet 41c of the refrigerant flow path 41a are formed on the upper surface of the cooling member 41. The inlet 41b is connected to the downstream end of the first refrigerant pipe 42, and the outlet 41c is connected to the upstream end of the second refrigerant pipe 43. The upstream end of the first refrigerant pipe 42 and the downstream end of the second refrigerant pipe 43 are connected to the refrigerant cooling source 44.

[0072] The refrigerant flows into the refrigerant cooling source 44 from the downstream end of the second refrigerant pipe 43. The refrigerant can be either a liquid or a 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 can also 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. The low-temperature refrigerant flows in the refrigerant flow path 41a, and thus, 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 has flowed through the refrigerant flow path 41a and has been heated flows into the refrigerant cooling source 44 again through the second refrigerant pipe 43 and is cooled again by the refrigerant cooling source 44.

[0073] If 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 top surface of the chamber 10), is also cooled. In Figure 1 the example, when viewed from above, the size of the cooling member 41 is larger than that of the substrate 9. That is, when viewed from above, the outline of the cooling member 41 surrounds the outline of the substrate 9. If the cooling member 41 is rectangular when viewed from above, 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. Thus, the cooling member 41 can appropriately cool the entire surface of the cooling surface 40a that faces the entire surface of the first surface F1 of the substrate 9. The above rectangle can also be a square, and in this case, it is sufficient that the side length of the cooling member 41 is larger than the short side of the substrate 9. In this way, regardless of the orientation of the substrate 9 disposed on the support portion 20, when viewed from above, the cooling member 41 is larger than the substrate 9. 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 surface of the first surface F1 of the substrate 9.

[0074] <1-1-6. Bottom surface rectifying plate 50>

[0075] The bottom surface rectifying plate 50 is a plate for restricting the flow of gas in the internal space 10s when the chamber 10 is decompressed by the decompression mechanism 30. For example, the bottom surface rectifying plate 50 is disposed between the substrate 9 supported by the support portion 20 and the bottom plate portion 11 of the chamber 10. The bottom surface rectifying plate 50 is fixed to the bottom plate portion 11 of the chamber 10 by, for example, a plurality of pillars (not shown). As Figure 2As shown, for example, when viewed from above, the shape of the bottom surface rectifying plate 50 is square. And, for example, when viewed from above, the length of each side of the bottom surface rectifying plate 50 is greater than the short side of the rectangular substrate 9. Therefore, for example, regardless of the direction of the substrate 9 disposed on the support portion 20, when viewed from above, the bottom surface rectifying plate 50 is larger than the substrate 9. In addition, the bottom surface rectifying plate 50 has, for example, a through hole 50h in a state where the moving portion 100b of the first lifting portion 100 passes through it. The bottom surface rectifying plate 50 and the moving portion 100b are separated by a very small interval at the through hole 50h.

[0076] <1-1-7. Side rectifying plate 51>

[0077] The side rectifying plate 51 is a plate for restricting the flow of gas in the internal space 10s together with the bottom surface rectifying plate 50 when the chamber 10 is evacuated by the evacuation mechanism 30. For example, the side rectifying plate 51 is disposed so as to be located between the substrate 9 supported by the support portion 20 at the lowered position H2 and the side wall portion 12 of the chamber 10. Here, for example, four side rectifying plates 51 are disposed so as to surround the periphery of the substrate 9 supported by the support portion 20. For example, the four side rectifying plates 51 as a whole form a rectifying plate in the shape of a square tube surrounding the substrate 9. In addition, for example, the bottom surface rectifying plate 50 and the four side rectifying plates 51 as a whole form a box-shaped rectifying plate with a bottom tube shape. Furthermore, in Figure 1 the example, the upper end of the side rectifying plate 51 is lower than the second surface F2 of the substrate 9 supported by the support portion 20 at the raised position H1. Therefore, in the first state where the support portion 20 is at the raised position H1, the substrate 9 is not surrounded by the four side rectifying plates 51.

[0078] Here, for example, when evacuating the chamber 10 in the second state where the support portion 20 is at the lowered position H2, the gas directly above the substrate 9 mainly flows to the upper end of the side rectifying plate 51 (see Figure 13 described later). This gas sequentially passes through the space between the side rectifying plate 51 and the side wall portion 12, the space between the bottom surface rectifying plate 50 and the bottom plate portion 11, and the exhaust ports 16a, 16b, 16c, 16d, and is discharged to the outside of the chamber 10. In this way, the gas flows in the space far from the substrate 9, so that it is not easy to form an air flow near the substrate 9. And it is not easy to generate a concentrated air flow at the peripheral portion of the substrate 9. Thus, for example, it is possible to suppress uneven drying of the coating film 90 formed on the upper surface of the substrate 9.

[0079] In addition, here, for example, it is adopted as Figure 2The structure shown, that is, when viewed from above, the four exhaust ports 16a, 16b, 16c, and 16d are all located on the diagonal line 52 of the square bottom fairing 50. In this case, for example, through each of the exhaust ports 16a, 16b, 16c, and 16d, an air flow symmetric with respect to the center of the bottom fairing 50 (the intersection of the two diagonal lines 52) can be formed. Thus, for example, in the internal space 10s of the chamber 10, a more uniform air flow can be formed.

[0080] <1-1-8. Gas supply mechanism 60>

[0081] The gas supply mechanism 60 is a part that performs the action of supplying gas into the chamber 10 (also referred to as gas supply). As Figure 1 shown, for example, a gas supply port 16f is provided on the bottom plate portion 11 of the chamber 10. The gas supply port 16f is, for example, located below the bottom fairing 50. The gas supply mechanism 60 is installed at the gas supply port 16f of the chamber 10. The gas supply mechanism 60 has a gas supply source 62, a buffer portion 63 (first buffer portion) between the gas supply port 16f of the chamber 10 and the gas supply source 62, a gas supply valve V1 (first gas supply valve) between the gas supply port 16f of the chamber 10 and the buffer portion 63, and a gas supply valve V2 (second gas supply valve) between the buffer portion 63 and the gas supply source 62. In addition, these components can be connected by a gas supply pipe 61. In Figure 1 this case, one end of the gas supply pipe 61 is connected to the gas supply port 16f, the other end of the gas supply pipe 61 is connected to the gas supply source 62, and the buffer portion 63 and the gas supply valves V1 and V2 are provided on the path of the gas supply pipe 61.

[0082] Here, first, if both the gas supply valves V1 and V2 are in the open state, gas is supplied from the gas supply source 62 to the internal space 10s of the chamber 10 via the gas supply pipe 61, the buffer portion 63, and the gas supply port 16f. Thus, the pressure inside the chamber 10 can be increased, and this pressure can be increased to atmospheric pressure. Second, when the chamber 10 is in a decompressed state, if the gas supply valve V2 is closed and the gas supply valve V1 is switched from the closed state to the open state, a predetermined amount of gas stored in the buffer portion 63 is supplied from the buffer portion 63 to the internal space 10s of the chamber 10 via the gas supply pipe 61 and the gas supply port 16f. Thus, the pressure inside the chamber 10 can be increased. The gas stored in the buffer portion 63 can have a pressure equivalent to the gas supply pressure from the gas supply source 62 at the moment before starting to be supplied to the internal space 10s of the chamber 10. The buffer portion 63 is a container that can temporarily store a predetermined amount of gas supplied from the gas supply source 62. For example, a gas supply tank, or a pipe with a length sufficient to obtain an adequate internal volume. The volume of the buffer portion 63 can be smaller than the volume of the chamber 10. The above-mentioned predetermined amount can be an amount less than the amount that can make the chamber 10 in a sufficient decompressed state reach atmospheric pressure.

[0083] The gas supplied from the gas supply source 62 can be, for example, an inert gas such as nitrogen, or clean and dry air. Clean and dry air can be prepared, for example, by cleaning the air in the ordinary environment to remove particles and moisture.

[0084] In order to supply the above-mentioned specified amount of gas from the gas supply mechanism 60 into the chamber 10 in a decompressed state, the control unit 80 controls the gas supply mechanism 60 so that the gas supply valve V2 remains closed and the gas supply valve V1 is switched from the closed state to the open state. In addition, as described above, in this first embodiment, when supplying the above-mentioned specified amount of gas, the control unit 80 controls the decompression mechanism 30 so that the vacuum pump 32 exhausts the chamber 10. That is to say, supplying the above-mentioned specified amount of gas into the chamber 10 and exhausting the chamber 10 are carried out simultaneously. The control unit 80 controls the gas supply mechanism 60 to supply, after supplying the above-mentioned specified amount of gas from the gas supply mechanism 60 into the chamber 10 in a decompressed state, an amount of gas that makes the pressure in the chamber 10 become atmospheric pressure from the gas supply mechanism 60.

[0085] <1-1-9. Pressure gauge 70>

[0086] The pressure gauge 70 is a sensor that measures the pressure in the chamber 10, in other words, the pressure in the internal space 10s of the chamber 10. In addition, when there is a mixed gas in the chamber 10, the pressure referred to here means the total pressure. As Figure 1 shown, the pressure gauge 70 is installed on a part of the chamber 10. The pressure gauge 70 can measure the pressure in the internal space 10s of the chamber 10 and can output the measurement result to the control unit 80.

[0087] <1-1-10. Control unit 80>

[0088] The control unit 80 is a unit (electronic circuit) for controlling the operations of the various parts of the vacuum drying apparatus 1. The control unit 80 can control structures such as the vacuum mechanism 30, the cooling unit 40, the air supply mechanism 60, and the first lifting unit 100. The control unit 80 is constituted, for example, by a computer having 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 referred to as a program) 803p for executing the vacuum drying method and various data. The storage unit 803 stores the program 803p, for example, and functions as a non-temporary storage medium readable by a computer. The control unit 80 reads the program 803p and data from the storage unit 803 into the memory 802, for example, and performs arithmetic processing based on the program 803p and data in the processor 801, thereby controlling the operations of the various parts of the vacuum drying apparatus 1. Therefore, for example, in the vacuum drying apparatus 1, the program 803p is executed by the processor 801 included in the control unit 80, so that the vacuum drying process can be performed.

[0089] For example, an input unit 804, an output unit 805, a communication unit 806, and a driver 807 may be connected to the control unit 80. The input unit 804 is a part that inputs various signals to the control unit 80 in response to a user's operation or the like. The input unit 804 may include, for example: an operation unit that inputs a signal corresponding to the user's operation; a microphone that inputs a signal corresponding to the user's voice; various sensors that input a signal corresponding to the user's movement, etc. The output unit 805 is a part that outputs various information in a manner recognizable by the user. The output unit 805 may include, for example, a display unit, a projector, a speaker, etc. The display unit may also be a touch panel integrated with the input unit 804. The communication unit 806 is a part that transmits and receives various information to and from an external device such as a server using wired or wireless communication means, etc. For example, the program 803p received from the external device using the communication unit 806 may be stored in the storage unit 803. The driver 807 is a part that can detachably mount a portable storage medium 807m such as a magnetic disk or an optical disk. The driver 807 transmits and receives data between the storage medium 807m and the control unit 80, for example, in a state where the storage medium 807m is mounted. For example, by mounting a storage medium 807m storing the program 803p on the driver 807, the program 803p can 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 functions as a non-temporary storage medium readable by a computer.

[0090] Figure 6 is a block diagram conceptually showing the functions implemented by the control unit 80. As Figure 6As shown, the control unit 80 is electrically connected to, for example, the opening / closing drive unit 16, the first elevating unit 100, the four independent valves Va, Vb, Vc, Vd, the main valve Vm, the vacuum pump 32, the air supply valves V1, V2, the cooling unit 40, and the pressure gauge 70. The control unit 80 can control the operations of the above-described units by referring to, for example, the measured values output from the pressure gauge 70.

[0091] As Figure 6 Conceptually shown, as a functional structure to be implemented, the control unit 80 includes, for example, an opening / closing control unit 81, an elevating 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. For example, the opening / closing control unit 81 controls the operation of the opening / closing drive unit 16. For example, the elevating control unit 82 controls the operation of the first elevating unit 100. For example, the switching control unit 83 controls the opening / closing states of the four independent valves Va, Vb, Vc, Vd, respectively. For example, the exhaust control unit 84 controls the opening / closing state and the opening degree of the main valve Vm. 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 states of the air supply valves V1, V2. For example, the cooling control unit 87 controls the operation of the cooling unit 40. The functions of the respective units of the control unit 80 are realized, for example, by the processor 801 included in the control unit 80 performing arithmetic processing based on the above-described program 803p and the like.

[0092] <1-2. Vacuum drying method>

[0093] Next, a vacuum drying method for drying a coating film 90 applied to the upper surface of a substrate 9 using the vacuum drying apparatus 1 will be described. Figure 7 is a flowchart showing an example of the process of the vacuum drying method according to the first embodiment. The process of this vacuum drying method is realized, for example, by executing the program 803p in the processor 801 included in the control unit 80. Here, for example, the processes of step S10 to step S60 Figure 7 are sequentially executed.

[0094] In step S10, the substrate 9 is carried into the chamber 10. At this time, the state is such that an undried coating film 90 is formed on the first surface F1 of the substrate 9. In step S10, for example, the gate portion 15 opens the carry-in outlet 14 under the control of the control unit 80, and a transfer robot (not shown) places the substrate 9 on the forked hand portion and carries the substrate 9 into the internal space 10s of the chamber 10 via the carry-in / carry-out port 14 of the chamber 10. At this time, the support portion 20 is located, for example, at the lowered position H2. In addition, the side rectifying plate 51 is configured to be movable so that the side rectifying plate 51 does not interfere with the transfer robot. The transfer robot, for example, inserts the forked hand portion between the plurality of support plates 21 of the support portion 20, places the substrate 9 on the support portion 20, and then retracts the forked hand portion to the outside of the chamber 10. Then, under the control of the control unit 80, the gate portion 15 closes the carry-in / carry-out port 14. As described above, in step S10, the process of placing the substrate 9 on the plurality of support pins 22 arranged in the chamber 10 (also referred to as the placement process) is performed. In addition, to illustrate the state of the valves in step S10, the independent valves Va to Vd, the main valve Vm, and the supply valves V1 and V2 are set to the closed state.

[0095] In step S20, while cooling the cooling surface 40a facing the upper surface of the substrate 9 supported by the support portion 20 in the chamber 10 at a distance, the pressure in the chamber 10 is reduced by sucking gas from the chamber 10, and the solvent evaporates from the coating film 90 on the substrate 9 and condenses on the cooling surface 40a. Specifically, the following processing is performed.

[0096] The control unit 80 activates the cooling unit 40, whereby the cooling unit 40 cools the cooling surface 40a and reduces the temperature of the cooling surface 40a. The cooling unit 40 reduces the temperature of the cooling surface 40a to the target temperature. The target temperature is, for example, 5 degrees Celsius or more and 20 degrees Celsius or less. As a more specific example, the target temperature is about 15 degrees Celsius. The cooling unit 40 can continuously perform the cooling operation of the cooling surface 40a until the processing of the substrate 9 is completed. In addition, this cooling operation performed by the cooling unit 40 can also be started before step S10.

[0097] Next, the pressure reduction drying device 1 performs a first interval adjustment process. The first interval adjustment process is a process of setting the interval between the substrate 9 and the cooling surface 40a to the first interval. Specifically, the control unit 80 controls the first lifting unit 100 to raise the support portion 20 to the raised position H1. In the first state where the support portion 20 is located at the raised position H1, the substrate 9 is located above the upper end of the side rectifying plate 51 (see Figure 1 ).

[0098] Next, the vacuum pump 32 is started and at least one of the independent valves Va to Vd and the main valve Vm are set to the open state. Thus, the reduced-pressure drying apparatus 1 performs a first reduced-pressure treatment. The first reduced-pressure treatment is a treatment for reducing the pressure in the chamber 10 to a first pressure (hereinafter referred to as the first target pressure). The first target pressure is lower than the standard atmospheric pressure. For example, it is set to 10 kPa or more. Specifically, the control unit 80 reduces the pressure in the chamber 10 by causing the reduced-pressure mechanism 30 to suck the gas in the chamber 10 at a relatively small first suction flow rate. For example, the control unit 80 can make the opening degree of the main valve Vm smaller than that during the subsequent second reduced-pressure treatment. Thus, in the first reduced-pressure treatment, the pressure in the chamber 10 decreases at a relatively low decreasing speed. In addition, to illustrate the states of the valves in this treatment, the independent valves Va to Vd and the main valve Vm are set to the open state, and the supply valves V1 and V2 are set to the closed state. In addition, for example, the control unit 80 can also appropriately control the opening and closing states of the plurality of independent valves Va, Vb, Vc, and Vd respectively. Thus, the air flow in the chamber 10 can be controlled to suppress the occurrence of uneven drying of the substrate 9.

[0099] Figure 8 and Figure 9 is a diagram schematically showing an example of the state in the chamber 10 during the first reduced-pressure treatment. Figure 8 shows the entire chamber 10, Figure 9 and magnifies and shows the vicinity of the cooling surface 40a and the substrate 9 in the chamber 10.

[0100] As Figure 8 shown, during the first reduced-pressure treatment, in the first state where the support portion 20 is in the raised position H1, the interval between the substrate 9 and the cooling surface 40a is very narrow. Therefore, the decreasing speed of the pressure in the upper space 10s1 becomes lower, and the occurrence of film boiling on the first surface F1 of the substrate 9 can be suppressed.

[0101] 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 flow rectifying plate 51. Therefore, the air flow regulating function of the side flow rectifying plate 51 hardly acts on the upper space 10s1 between the substrate 9 and the cooling surface 40a. Therefore, the side flow rectifying plate 51 basically does not bring an effect of suppressing the occurrence of uneven drying. In the first state, since the lower space 10s2 below the substrate 9 is spacious, the gas in the lower space 10s2 can be quickly discharged. Specifically, the gas in the lower space 10s2 passes between the side flow rectifying plate 51 and the side wall portion 12 of the chamber 10 and is discharged from the chamber 10. In Figure 8 it, this air flow is schematically shown by a dotted arrow.

[0102] By the first pressure reduction treatment, the pressure in the chamber 10 is reduced, so that the solvent of the coating film 90 on the first surface F1 of the substrate 9 evaporates. In Figure 9 the figure, the flow of the solvent vapor from the coating film 90 is schematically indicated by a dotted arrow. In the first pressure reduction treatment, since the cooling unit 40 cools the cooling surface 40a, the solvent vapor from the coating film 90 is cooled and condensed on the cooling surface 40a. That is, as Figure 9 shown, the 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 in a state where the pressure in the chamber S510 reaches the first target pressure. As a more specific example, the target temperature of the cooling surface 40a is set to be less than or equal to the temperature at which the pressure reaches the first target pressure in the vapor pressure curve of the solvent. Thereby, the solvent 91 can adhere to the area of the cooling surface 40a opposite to the coating film 90 substantially uniformly. In this way, the solvent vapor in the upper space 10s1 condenses on the cooling surface 40a, so that the concentration of the solvent vapor in the upper space 10s1 is reduced, and when viewed from above, the concentration distribution of the solvent vapor becomes more uniform.

[0103] For comparison, a comparative structure without the cooling unit 40 will be described. Figure 10 FIG. is an enlarged view showing the top plate portion 13 of the chamber 10 and the substrate 9 of the comparative structure. In Figure 9 the example, the lower surface 13a of the top plate portion 13 of the chamber 10 is not cooled by the cooling unit 40. The temperature of the lower surface 13a of the top plate portion 13 is, for example, approximately normal temperature.

[0104] In the first pressure reduction treatment, since the gap between the substrate 9 and the lower surface 13a is narrow, the solvent vapor from the coating film 90 immediately collides with the lower surface 13a of the top plate portion 13. Therefore, the solvent vapor easily stays in the central region of the upper space 10s1 opposite to the central portion of the coating film 90. On the other hand, in the peripheral region of the upper space 10s1 opposite to the peripheral portion of the coating film 90, due to concentration diffusion, the solvent vapor can flow out in the horizontal direction. Therefore, compared with the central portion, the peripheral portion of the coating film 90 is more likely to evaporate. That is, the coating film 90 will have uneven drying.

[0105] Figure 11 FIG. is a diagram showing an example of the concentration distribution of the solvent vapor in the upper space 10s1 of the comparative structure. Figure 11 (a) of the figure shows the concentration distribution of the solvent vapor when viewed from above, Figure 11 (b) of the figure shows the concentration distribution of the solvent vapor when viewed from the side. In Figure 11In (a) thereof, the concentration distribution of the solvent vapor is represented by contour lines T1 to T10. For the contour lines T1 to T10, the smaller the marked number, the higher the represented concentration. That is to say, among the contour lines T1 to T10, the contour line T1 represents the highest concentration. In Figure 11 In (b) thereof, the concentration distribution of the solvent vapor is represented by contour lines T11 to T21. For the contour lines T11 to T21, the smaller the marked number, the higher the represented concentration. That is to say, among the contour lines T11 to T21, the contour line T11 represents the highest concentration.

[0106] It can be obtained from Figure 11 (a) thereof that in the comparison structure, the solvent vapor flows from the periphery of the coating film 90 to the outside. In addition, as shown in Figure 11 (b) thereof, in the peripheral region 10r opposite to the peripheral portion of the coating film 90 in the upper space 10s1, the lower the concentration of the solvent vapor is towards the outside of the coating film 90. From this, it can be known that the peripheral portion of the coating film 90 is more likely to evaporate than the central portion.

[0107] Figure 12 is a diagram showing an example of the concentration distribution of the solvent vapor in the upper space 10s1 in a state where cooling is performed in the cooling unit 40. Figure 12 (a) thereof represents the concentration distribution of the solvent vapor in a top view, Figure 12 (b) thereof represents the concentration distribution of the solvent vapor in a side view. It can be obtained from Figure 12 (a) thereof that the solvent vapor does not flow out much from the periphery of the coating film 90. This is because the solvent vapor from the coating film 90 is cooled and condensed on the cooling surface 40a. That is to say, whether it is the solvent vapor from the central portion of the coating film 90 or the solvent vapor from its peripheral portion, both flow upward in an upward air flow corresponding to the temperature difference with the cooling surface 40a and condense on the cooling surface 40a (see Figure 9 ). Thus, since the solvent vapor from the peripheral portion also condenses on the cooling surface 40a, the solvent vapor does not flow much to the outside. In addition, the solvent vapor from the coating film 90 does not stay much in the upper space 10s1.

[0108] As shown in Figure 12 (b) thereof, in the peripheral region 10r, although the lower the concentration of the solvent vapor is in the vertical direction as it is farther away from the coating film 90, it is substantially uniform in the horizontal direction.

[0109] Therefore, it is possible to reduce the difference in the evaporation amount between the central portion and the peripheral portion of the coating film 90, and to suppress the occurrence of uneven drying. In addition, since the concentration of the solvent vapor in the upper space 10s1 is reduced by the condensation of the solvent vapor on the cooling surface 40a, the evaporation of the coating film 90 can also be promoted. Therefore, the processing ability of the vacuum drying method can also be improved.

[0110] After the above step S20, in step S30, the solvent is further evaporated from the coating film 90. For example, when the pressure in the chamber 10 reaches the first target pressure, the transfer from step S20 to step S30 is executed. Specifically, in order to promote this evaporation, the following processing is executed.

[0111] The vacuum drying apparatus 1 performs a second interval adjustment process. The second interval adjustment process is a process of setting the interval between the substrate 9 and the cooling surface 40a to a second interval. Specifically, the control unit 80 controls the first elevating unit 100 and lowers the support unit 20 to the lowered position H2. In the second state where the support unit 20 is located at the lowered position H2, the substrate 9 is located at a position closer to the lower side than the upper end of the side rectifying plate 51.

[0112] Next, the vacuum drying apparatus 1 performs a second pressure reduction process. The second pressure reduction process is a process of reducing 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 causes the pressure reduction mechanism 30 to suck the gas in the chamber 10 at a second suction flow rate greater than the first suction flow rate, thereby reducing the pressure in the chamber 10. For example, the control unit 80 can set the opening degree of the main valve Vm to be larger than the opening degree during the first pressure reduction process. The pressure in the chamber 10 is reduced to the second target pressure at a reduction speed higher than the reduction speed during the first pressure reduction process. In the second pressure reduction process, the vacuum drying apparatus 1 can maintain the pressure in the chamber 10 at the second target pressure for a specified period. The second target pressure is, for example, less than 10 kPa and greater than or equal to 0.1 Pa.

[0113] In step S30, for example, the control unit 80 can independently and appropriately control the opening and closing states of each of the plurality of independent valves Va, Vb, Vc, Vd. Thereby, the air flow in the chamber 10 can be controlled to suppress uneven drying of the substrate 9.

[0114] Figure 13 is a diagram schematically showing an example of the state in the chamber 10 during the second pressure reduction process. As Figure 13As shown, in the second state where the support portion 20 is in the lowered position H2, the gap between the substrate 9 and the cooling surface 40a is wide. In other words, the height of the upper space 10s1 is large. Therefore, different from the first pressure reduction process, the solvent vapor from the coating film 90 easily flows upward and it is not easy to cause the retention of the solvent vapor. Because the upper space 10s1 is large, the pressure in the upper space 10s1 can be reduced to the second target pressure more appropriately and quickly.

[0115] In addition, in the second state, the substrate 9 supported by the support portion 20 is surrounded by four side rectifying plates 51. Therefore, the rectifying function of the side rectifying plates 51 acts on the upper space 10s1 between the substrate 9 and the cooling surface 40a. That is to say, the concentration of the air flow toward the peripheral portion of the substrate 9 can be suppressed by the side rectifying plates 51. Therefore, the drying unevenness of the coating film 90 caused by the air flow can be further suppressed.

[0116] When the pressure in the chamber 10 reaches the second target pressure, the solvent of the coating film 90 boils and the drying of the coating film 90 proceeds at a higher speed. The pressure reducing mechanism 30 can suck the gas in the chamber 10 so that the pressure in the chamber 10 is approximately constant at the second target pressure. That is to say, the pressure reducing mechanism 30 can maintain the pressure in the chamber 10 at the second target pressure within a specified period. In addition, in the second pressure reduction process, the target temperature of the cooling surface 40a can be set to the temperature at which the solvent evaporates in a state where the pressure in the chamber 10 is the second target pressure. Thus, the solvent 91 attached to the cooling surface 40a also evaporates. As a more specific example, the target temperature of the cooling surface 40a can be set to be greater than or equal to the temperature at which the pressure reaches the second target pressure in the vapor pressure curve of the solvent.

[0117] The solvent vapor from the coating film 90 and the cooling surface 40a flows into the space between the side rectifying plate 51 and the side wall portion 12 of the chamber 10 from the upper end side of the side rectifying plate 51 and is discharged to the outside through the exhaust ports 16a, 16b, 16c, 16d. In Figure 13 this, the flow of these solvent vapors is schematically shown by the dotted arrows.

[0118] When the boiling of the coating film 90 ends, that is to say, when the specified period has elapsed, the pressure reducing mechanism 30 can further reduce the pressure in the chamber 10. In other words, the pressure reducing mechanism 30 can reduce the pressure in the chamber 10 to a third target pressure lower than the second target pressure. Thereby, the drying of the coating film 90 and the evaporation of the solvent 91 attached to the cooling surface 40a can be further promoted.

[0119] As described above, in the second pressure reduction process, the first elevating unit 100 lowers the support unit 20 to the lowered position H2, and the pressure reduction mechanism 30 reduces the pressure in the chamber 10 to be less than or equal to the second target pressure. Thereby, in the second pressure reduction process, the pressure reduction drying apparatus 1 can dry the coating film 90 on the first surface F1 of the substrate 9. Thereby, the evaporation of the solvent 91 attached to the cooling surface 40a can be promoted. However, the evaporation of the solvent 91 is relatively slow. Therefore, if only the second pressure reduction process is used to sufficiently dry the cooling surface 40a, it is inevitable that the second pressure reduction process needs to be performed for a long time, and as a result, the production efficiency is reduced. Therefore, the following step S40 is performed to dry the cooling surface 40a in a shorter time.

[0120] In step S40, by supplying a predetermined amount of gas into the chamber 10, the pressure in the chamber 10 is increased, and the solvent on the cooling surface 40a is evaporated to sufficiently dry the cooling surface 40a. Specifically, in order to supply the predetermined amount of gas from the gas supply mechanism 60 into the chamber 10 in a reduced pressure state, the gas supply valve V2 is kept closed, and the gas supply valve V1 is switched from the closed state to the open state. In the present first embodiment, when the predetermined amount of gas is supplied, the pressure reduction mechanism 30 is controlled to exhaust the chamber 10 by the vacuum pump 32. That is, supplying the predetermined amount of gas into the chamber 10 and exhausting the chamber 10 are performed simultaneously.

[0121] When gas is supplied into the chamber 10 in a reduced pressure state, first, in the chamber 10, the vapor of the solvent is mixed with the gas, which causes an increase in entropy, and this promotes the change of the liquid solvent 91 attached to the cooling surface 40a into vapor. Second, the temperature in the chamber 10 rises due to the supplied gas, which also promotes the evaporation of the solvent 91 attached to the cooling surface 40a. Third, in the present first embodiment, by supplying gas and exhausting at the same time, the discharge of the solvent vapor from the chamber 10 can be promoted, which also promotes the evaporation of the solvent 91 attached to the cooling surface 40a. The predetermined amount of the gas is set to an amount that can sufficiently promote the evaporation of the solvent 91.

[0122] Figure 14 is a graph showing the change in the pressure in the chamber 10 with time from the end of step S20 to step S60 described later. In step S40, the pressure has a peak value by supplying the predetermined amount of gas. From just before this peak value to this peak value, the pressure in the chamber 10 can be from lower than the vapor pressure Ps of the solvent at the temperature of the cooling surface 40a (see Figure 14The state change from a lower state (dashed line) to a higher state, but in this case, it is preferable to return to a state lower than the vapor pressure Ps again just after this peak. Therefore, in order not to make the overall time required for step S40 too long, preferably, the peak pressure in step S40 is not increased excessively. This peak pressure can be lower than atmospheric pressure or lower than the above-mentioned first target pressure. In order to meet such pressure conditions, preferably, the above-mentioned specified amount of gas is not made excessive.

[0123] Figure 15 is a graph showing the change in pressure over time in a comparative example, in which, instead of steps S30 and S40 of this first embodiment ( Figure 14 ) step S30C is performed. Step S30C ( Figure 15 ) extends the time of step S30 ( Figure 14 ) by the time of step S40 ( Figure 14 ). Therefore, in this first embodiment and the comparative example, the time required for the single-step vacuum drying method is the same. In particular, in the latter half of step S30C of the comparative example, there is almost no gas other than solvent vapor in the chamber 10, and the evaporation rate of the solvent 91 is lower than that of step S40 of this first embodiment. As a result, even at the end of step S30C, the cooling surface 40a is likely to remain with the liquid solvent 91. Even if this remaining degree can be ignored after performing the single-step vacuum drying method, if the vacuum drying method is repeatedly performed, the liquid solvent 91 will accumulate on the cooling surface 40a. If the accumulated liquid solvent 91 drips onto the substrate 9, the quality of the product using the substrate 9 will be impaired. Although this problem can be solved by extending the time of step S30C, this is likely to cause a significant reduction in production efficiency.

[0124] In step S50, a specific amount of gas is supplied, and the specific amount is the amount that forms atmospheric pressure in the chamber 10. Specifically, the independent valves Va to Vd and the main valve Vm are controlled to disconnect the vacuum pump 32 from the chamber 10. In this state, not only is the gas supply valve V1 set to the open state, but also the gas supply valve V2 is set to the open state. As a result, gas is supplied from the gas supply source 62 to the internal space 10s of the chamber 10. As a result, the pressure in the chamber 10 rises to atmospheric pressure again.

[0125] In step S60, the substrate 9 is taken out of the chamber 10. For example, first, under the control of the control unit 80, the gate portion 15 opens the carry-in / outlet 14, and the illustrated transfer robot omits carrying out the dried substrate 9 placed on the support portion 20 from the chamber 10 through the carry-in / outlet 14 of the chamber 10 to the outside of the chamber 10. Thus, the processing of one substrate 9 can be completed.

[0126] <1-3. Effects>

[0127] First, before supplying an amount of gas that can make the pressure in the chamber 10 become atmospheric pressure, gas is supplied into the chamber 10 in a decompressed state. Thereby, the evaporation of the solvent condensed on the cooling surface 40a of the cooling unit 40 can be promoted. Therefore, excessive accumulation of the liquid solvent on the cooling surface 40a of the cooling unit 40 can be avoided. Second, the amount of the supplied gas is set to a specified amount. Thereby, the amount of the supplied gas can be controlled to a sufficient amount required to promote the above evaporation. Therefore, excessive reduction in production efficiency due to an excessive amount of the supplied gas can be avoided. In summary, both excessive reduction in production efficiency and excessive accumulation of the liquid solvent on the cooling surface 40a of the cooling unit 40 can be avoided.

[0128] In addition, assuming that the buffer unit 63 and the gas supply valve V2 are omitted from the vacuum drying apparatus 1( Figure 1 ), it is difficult to supply a specified amount of gas into the chamber 10 in a decompressed state as in the first embodiment of the present invention because it is difficult to stably control the amount of the supplied gas. If the amount of the gas is insufficient, the above effects brought by the gas cannot be obtained sufficiently. Therefore, if a large amount of gas is supplied to ensure the amount of the gas sufficiently, the generated air flow easily causes the substrate 9 to deviate from the normal position, the substrate 9 to fall, or the substrate 9 to be damaged.

[0129] Further, in the first embodiment of the present invention, when supplying a specified amount of gas, the vacuum pump 32 evacuates the chamber 10. Thereby, the pressure in the chamber 10 increased due to the gas supply can be rapidly reduced.

[0130] In addition, the control unit 80 can control the first lifting unit 100 and the decompression mechanism 30 to set the pressure in the chamber 10 to a first pressure in a first state where the interval between the substrate 9 and the cooling surface 40a is a first interval, and then set the pressure in the chamber 10 to a second pressure in a second state where the interval between the substrate 9 and the cooling surface 40a is a second interval.

[0131] Specifically, first, in the first decompression process, in a state where 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, the decompression mechanism 30 can lower the pressure in the chamber 10 to a first target pressure. In the first decompression process, since the support unit 20 is located at the raised position H1, the interval between the substrate 9 and the cooling surface 40a is narrow. Therefore, a sharp drop in the pressure in the upper space 10s1 between the substrate 9 and the cooling surface 40a can be suppressed, and the occurrence of boiling over of the coating film 90 can be suppressed.

[0132] In addition, in the first pressure reduction process, the cooling unit 40 can cool the cooling surface 40a. More specifically, the cooling unit 40 can reduce the temperature of the cooling surface 40a to a target temperature at which the solvent vapor condenses under the first target pressure. Thereby, the solvent vapor from the coating film 90 on the substrate 9 condenses on the cooling surface 40a. Therefore, the retention of the solvent vapor in the upper space 10s1 (particularly, the central region) can be suppressed, and the occurrence of uneven drying of the coating film 90 can be suppressed.

[0133] On the other hand, in the second pressure reduction process after the first pressure reduction process, in a state where the first lifting unit 100 lowers the support unit 20 to the lowered position H2, the pressure reduction mechanism 30 can lower the pressure in the chamber 10 below the second target pressure. Since the support unit 20 is located at the lowered position H2, the gap between the substrate 9 and the cooling surface 40a is wide. Thereby, the pressure in the chamber 10 can be reduced more appropriately and rapidly. Therefore, the coating film 90 can be dried more appropriately and rapidly. In addition, in the second pressure reduction process, since the gap between the substrate 9 and the cooling surface 40a is wide, the solvent vapor is less likely to be retained, and uneven drying is also less likely to occur.

[0134] In addition, in the second pressure reduction process, the temperature of the cooling surface 40a can be a temperature at which the solvent evaporates under the second target pressure. Therefore, in the second pressure reduction process, not only the coating film 90 on the substrate 9 but also the cooling surface 40a can be dried. Therefore, before processing the next substrate 9, the cooling surface 40a does not need to be dried separately, and the processing of the next substrate 9 can be carried out quickly. Thereby, the processing ability for processing a plurality of substrates 9 can be improved.

[0135] In addition, in the first embodiment, the top surface of the chamber 10 can correspond to the cooling surface 40a. Therefore, if the cooling unit 40 is externally connected to the upper surface of the chamber 10, the existing chamber 10 can be directly used.

[0136] In addition, in the first embodiment, the top plate portion 13 can be cooled by the cooling member 41 to cool the lower surface of the top plate portion 13, that is, the cooling surface 40a. When viewed from above, although the temperature distribution in the cooling member 41 is slightly deviated due to the extending shape of the refrigerant flow path 41a, due to the heat transfer in the top plate portion 13, the deviation of the temperature distribution becomes more moderate toward the cooling surface 40a. That is to say, the temperature distribution of the cooling surface 40a of the top plate portion 13 can be further uniformized. Therefore, the solvent vapor from the coating film 90 on the first surface F1 of the substrate 9 can be condensed more uniformly on the cooling surface 40a. Therefore, the uniformity of the concentration distribution of the solvent vapor in the upper space 10s1 can be improved. Thereby, the occurrence of uneven drying can be further suppressed.

[0137] In addition, in the first embodiment, the first lifting unit 100 that raises and lowers the support unit 20 can be adopted to adjust the interval between the substrate 9 and the cooling surface 40a. Therefore, the provided first lifting unit 100 can be directly used.

[0138] <2. Second Embodiment>

[0139] Figure 16 It is a graph showing the change of the pressure in the chamber 10 with time during the vacuum drying in the second embodiment. In the second embodiment, step S40 ( Figure 7 ) has steps S40a, S40b ( Figure 16 ). As step S40a ( Figure 16 ), when the gas supply mechanism 60 supplies a specified amount of gas into the chamber 10, different from the above first embodiment, the control unit 80 controls the independent valves Va to Vd and the main valve Vm to disconnect the vacuum pump 32 from the chamber 10. For example, the independent valves Va to Vd and the main valve Vm are set to the closed state. And the above specified amount of gas is supplied into the chamber 10 from the gas supply mechanism 60. Then, as step S40b ( Figure 16 ), the control unit 80 controls the independent valves Va to Vd and the main valve Vm to exhaust the chamber 10 with the vacuum pump 32. For example, the independent valves Va to Vd and the main valve Vm are set to the open state. The supply (step S40a) and discharge (step S40b) of the gas have the function of replacing the gas in the chamber 10. In addition, after step S40, steps S50 and S60 are executed in the same manner as in the first embodiment.

[0140] According to the second embodiment, when supplying the specified amount of gas, the vacuum pump 32 is disconnected from the chamber 10. Thus, the effect of the supplied gas can be more reliably manifested.

[0141] <3. Third Embodiment>

[0142] <3-1. Structural Outline of Vacuum Drying Device>

[0143] Figure 17 It is a diagram schematically showing an example of the longitudinal section of the vacuum drying device 1T of the third embodiment. Except for the structure of the gas supply mechanism 60 ( Figure 1 : the first embodiment) of the vacuum drying device 1, the gas supply mechanism 60M ( Figure 17 ) of the vacuum drying device 1T further includes a buffer portion 64 (second buffer portion) between the gas supply valve V2 and the gas supply source 62, and a gas supply valve V3 (third gas supply valve) between the buffer portion 64 and the gas supply source 62.

[0144] In order to supply a prescribed amount of gas, the control unit 80 of the vacuum drying apparatus 1T controls the gas supply mechanism 60M so that the gas supply valve V2 remains closed and the gas supply valve V1 is switched from the closed state to the open state. Thereafter, the control unit 80 of the vacuum drying apparatus 1T controls the gas supply mechanism 60M so that the gas supply valve V2 is switched from the closed state to the open state. Thus, first, by keeping the gas supply valve V2 closed and switching the gas supply valve V1 from the closed state to the open state, a part of the prescribed amount of gas is supplied from the buffer unit 63 into the chamber 10 in the reduced-pressure state. Then, by keeping the gas supply valve V3 closed and switching the gas supply valve V2 from the closed state to the open state, the other part of the prescribed amount of gas is supplied from the buffer unit 64 into the chamber 10 in the reduced-pressure state. The gas stored in the buffer unit 64 may have a pressure equivalent to the gas supply pressure from the gas supply source 62 at the moment before starting to supply the gas into the internal space 10s of the chamber 10.

[0145] In addition, since it is the same as the first or second embodiment described above, the description of features other than the above is omitted.

[0146] <3-2. Vacuum Drying Method>

[0147] Figure 18 It is a graph showing the change in the pressure in the chamber 10 with time during the vacuum drying in the third embodiment. In the vacuum drying method using the vacuum drying apparatus 1T, step S40 ( Figure 7 ) includes steps S40h and S40i.

[0148] In step S40h, in order to supply a part of the prescribed amount of gas from the gas supply mechanism 60M into the chamber 10 in the reduced-pressure state, the gas supply valve V2 is kept closed and the gas supply valve V1 is switched from the closed state to the open state. Thus, the gas stored in the buffer unit 63 is supplied into the chamber 10. In this third embodiment, when supplying a part of the prescribed amount of gas, the vacuum mechanism 30 is controlled so that the vacuum pump 32 evacuates the chamber 10. That is, supplying a part of the prescribed amount of gas into the chamber 10 and evacuating the chamber 10 are performed simultaneously.

[0149] Then, in step S40i, in order to supply the other part of the above-mentioned specified amount of gas from the gas supply mechanism 60M to the chamber 10 in the depressurized state, the gas supply valve V3 is kept closed, and not only the gas supply valve V1 but also the gas supply valve V2 is switched from the closed state to the open state. Thereby, the gas stored in the buffer portion 64 is supplied into the chamber 10. In the present third embodiment, when supplying the other part of the specified amount of gas, the pressure reducing mechanism 30 is controlled so that the vacuum pump 32 evacuates the chamber 10. That is, supplying the other part of the specified amount of gas into the chamber 10 and evacuating the chamber 10 are performed simultaneously.

[0150] <3-3. Effects>

[0151] According to the present third embodiment, the action described in the first embodiment can be manifested not once but twice. Thereby, the effect described in the first embodiment can be further improved.

[0152] <3-4. Modification Example>

[0153] The technology of the present third embodiment can be used in the second embodiment instead of the above-mentioned first embodiment. Specifically, at step S40, the pressure reducing mechanism 30 is controlled to disconnect the vacuum pump 32 from the chamber 10 during each of the first supply period of supplying a part of the specified amount of gas and the second supply period of supplying the other part of the specified amount of gas. In addition, the pressure reducing mechanism 30 is controlled so that the vacuum pump 32 evacuates the chamber 10 at each of the moments between the first supply period and the second supply period and at the moment after the second supply period. According to this modification example, the effect described in the second embodiment can be further improved.

[0154] <4. Fourth Embodiment>

[0155] Figure 19 is a diagram schematically showing an example of a longitudinal section of a vacuum drying apparatus 1A according to the fourth embodiment. Except for the second lifting portion 45, the structure of the vacuum drying apparatus 1A is the same as that of the vacuum drying apparatus 1. The second lifting portion 45 raises and lowers the cooling member 41 of the cooling portion 40 between the cooling position H3 and the separation 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 portion 13 of the chamber 10, and the separation position H4 is a position where the cooling member 41 is separated from the top plate portion 13. In Figure 19 the example of, the cooling member 41 located at the separation position H4 is schematically shown by a phantom line. For example, the second lifting portion 45 uses a driving device such as a linear motor or a cylinder.

[0156] The pressure-reducing drying method of the fourth embodiment is different from that of the first embodiment in that the position of the cooling member 41 is controlled. The cooling member 41 is initially located at the cooling position H3. Then, at the moment between the second interval adjustment process and the second pressure-reducing process in the pressure-reducing drying of the first embodiment, the pressure-reducing drying apparatus 1A performs a cooling part separation process. The cooling part separation process is a process of moving the cooling part 40 to the separation position H4. Specifically, the control unit 80 controls the second elevating part 45 to raise the cooling member 41 from the cooling position H3 to the separation position H4. The cooling member 41 rises to the separation position H4, thereby substantially interrupting the cooling of the cooling surface 40a.

[0157] As described above, according to the fourth embodiment, in the first pressure-reducing process, the cooling member 41 descends to the cooling position H3, and the lower surface of the cooling top plate part 13, that is, the cooling surface 40a. Therefore, the pressure-reducing drying apparatus 1A can more reliably condense the solvent vapor on the cooling surface 40a in the first pressure-reducing process. And according to the fourth embodiment, in the second pressure-reducing process, the cooling member 41 rises to the separation position H4. Therefore, in the second pressure-reducing process, the cooling of the cooling surface 40a can be substantially interrupted. The cooling member 41 moves away from the cooling surface 40a, and thus, as time passes, the temperature of the cooling surface 40a rises, so the evaporation of the solvent 91 attached to the cooling surface 40a can be promoted.

[0158] <5. Fifth Embodiment>

[0159] Figure 20 FIG. is an example of a longitudinal cross-section schematically showing the pressure-reducing drying apparatus 1B of the fifth embodiment. Except for the internal structure of the cooling part 40, the structure of the pressure-reducing drying apparatus 1B is the same as that of the pressure-reducing drying apparatus 1.

[0160] As Figure 20 shown, a part of the cooling part 40 of the pressure-reducing drying apparatus 1B is buried in the top plate part 13 of the chamber 10. Here, the top plate part 13 functions as the cooling member 41. The top plate part 13 can also be formed of a material with high thermal conductivity (for example, metal). In Figure 20 the example, a refrigerant flow path 41a that is a part of the cooling part 40 is formed inside the top plate part 13. The refrigerant flow path 41a can, for example, be meandering inside the top plate part 13 when viewed from above, or extend in a spiral shape. In Figure 20 the example, an inlet 41b and an outlet 41c of the refrigerant flow path 41a are formed on the upper surface of the top plate part 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.

[0161] The refrigerant cooling source 44 cools the refrigerant and circulates it, so that the top plate portion 13 of the chamber 10 can be cooled. That is, the lower surface of the top plate portion 13, namely the cooling surface 40a, can be cooled. In addition, a part of the cooling portion 40 embedded in the top plate portion 13 is a low-temperature portion that absorbs heat from the top plate portion 13. For example, when the cooling portion 40 has a cooling element such as a Peltier element, the cooling element is embedded in the top plate portion 13.

[0162] The example of the process of the vacuum drying method using the vacuum drying device 1B is the same as the vacuum drying method of the first or second embodiment. In addition, as a modification, the fifth embodiment can adopt the air supply mechanism 60M of the third embodiment ( Figure 17 ).

[0163] According to the fifth embodiment, since the top plate portion 13 functions as the cooling member 41, the number of components of the vacuum drying device 1B can be reduced. Therefore, the size of the vacuum drying device 1B can be reduced and the manufacturing cost can be lowered. In addition, since the interval between the refrigerant flow path 41a and the cooling surface 40a can be reduced, the cooling portion 40 can cool the cooling surface 40a more efficiently.

[0164] <6. Sixth Embodiment>

[0165] Figure 21 FIG. is an example of a longitudinal section schematically showing the vacuum drying device 1C of the sixth embodiment. Except for the internal structure of the cooling portion 40, the structure of the vacuum drying device 1C is the same as that of the vacuum drying device 1.

[0166] As Figure 21 shown, a part of the cooling portion 40 of the vacuum drying device 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 disposed at a position in the chamber 10 opposite to the first surface F1 of the substrate 9 supported by the support portion 20. That is, the cooling member 41 is disposed above the substrate 9 supported by the support portion 20. The cooling member 41 is disposed in the chamber 10 with its thickness direction along the vertical direction. The cooling member 41 is fixed to the chamber 10 by a fixing portion (not shown). The cooling member 41 can be fixed to the top plate portion 13 of the chamber 10 by a fixing portion such as a screw. In the sixth embodiment, the lower surface of the cooling member 41 corresponds to the cooling surface 40a.

[0167] In Figure 21 the example, the first refrigerant pipe 42 and the second refrigerant pipe 43 penetrate the top plate portion 13, and the refrigerant cooling source 44 is disposed outside the chamber 10. The refrigerant cooling source 44 cools the refrigerant and circulates it, so that the cooling member 41 can be cooled. That is, the cooling surface 40a of the cooling member 41 can be cooled.

[0168] In Figure 21 the example, when viewed from above, the size of the cooling member 41 is larger than that of the substrate 9. When viewed from above, the cooling surface 40a of the cooling member 41 may have the same rectangular shape as the substrate 9. At this time, the long side of the cooling surface 40a is larger than the long side of the substrate 9, and the short side of the cooling surface 40a is larger than the short side of the substrate 9. Thus, the cooling surface 40a can face the entire surface of the first surface F1 of the substrate 9 in the vertical direction. In addition, when viewed from above, the cooling surface 40a may be square. At this time, it is only necessary that the side length of the cooling surface 40a is larger than the short side of the substrate 9. Thus, regardless of the direction of the substrate 9 disposed on the support portion 20, when viewed from above, the cooling surface 40a is larger than the substrate 9. Therefore, regardless of the direction of the substrate 9, the cooling surface 40a can face the entire surface of the first surface F1 of the substrate 9.

[0169] An example of the process of the reduced-pressure drying method using the reduced-pressure drying apparatus 1C is the same as the reduced-pressure drying method in the first or second embodiment. In addition, as a modification, the sixth embodiment may adopt the air supply mechanism 60M of the third embodiment ( Figure 17 ).

[0170] According to the sixth embodiment, the cooling surface 40a is the lower surface of the cooling member 41 different from the chamber 10. Therefore, the material of the cooling member 41 having the cooling surface 40a can be separately selected differently from the specification requirements of the chamber 10. That is, the selectivity of the material of the cooling member 41 can be improved. In addition, since the cooling surface 40a is the lower surface of the cooling member 41, the interval between the low-temperature portion (here, the refrigerant flow path 41a) of the cooling portion 40 and the cooling surface 40a can be reduced. Therefore, the cooling portion 40 can cool the cooling surface 40a more efficiently.

[0171] <7. Seventh Embodiment>

[0172] Figure 22 is a diagram schematically showing an example of a longitudinal section of the reduced-pressure drying apparatus 1D of the seventh embodiment. Except for the lifting object of the first lifting portion 100, the structure of the reduced-pressure drying apparatus 1D is the same as that of the reduced-pressure drying apparatus 1C ( Figure 21 : the sixth embodiment). As Figure 22 shown, the first lifting portion 100 lifts and lowers the cooling portion 40. Specifically, the first lifting portion 100 lifts and lowers the cooling member 41 of the cooling portion 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 interval between the substrate 9 and the cooling surface 40a is the first interval. In Figure 22In [the figure], the cooling member 41 located at the lowered position H12 is indicated by a phantom 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 is the second distance. That is, the first elevating unit 100 elevates the cooling member 41 between a first state and a second state. In the first state, the distance between the substrate 9 and the cooling surface 40a is the first distance; in the second state, the distance between the substrate 9 and the cooling surface 40a is the second distance.

[0173] As Figure 22 shown, the support portion 20 is located at the lowered position H2 described in the first to sixth embodiments. That is, the substrate 9 supported by the support portion 20 is located at a position lower than the upper end of the side rectifying plate 51 and is surrounded by four side rectifying plates 51. In the seventh embodiment, in the first state where the distance between the substrate 9 and the cooling surface 40a is the first distance and in the second state where the distance between the substrate 9 and the cooling surface 40a is the second distance, the substrate 9 is surrounded by four side rectifying plates 51.

[0174] 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 rectifying plate 51. That is, in a top view, the size of the cooling member 41 is smaller than the size of the space surrounded by the four side rectifying plates 51.

[0175] The raised position H11 is a position where the cooling surface 40a of the cooling member 41 is higher than the upper end of the side rectifying plate 51. In a state where the cooling member 41 is located at the raised position H11, the distance between the cooling surface 40a and the upper end of the side rectifying plate 51 may be, for example, greater than or equal to twice the first distance or greater than or equal to five times the first distance. Thereby, the gas directly above the substrate 9 easily flows into the space between the side rectifying plate 51 and the side wall portion 12 of the chamber 10 from the upper end side of the side rectifying plate 51.

[0176] For example, the first elevating unit 100 employs a driving device such as a linear motor or a cylinder. The main body portion 100a of the first elevating unit 100 is fixed, for example, to a device rack (not shown) outside the chamber 10. The moving portion 100b of the first elevating unit 100 can move relative to the main body portion 100a in the vertical direction, for example. The moving portion 100b is, for example, a rod-shaped member or the like. The moving portion 100b is provided in a state of passing through a through hole 13h in the top plate portion 13 of the chamber 10, for example. And, for example, the cooling member 41 is fixed to the lower end portion of the moving portion 100b. Here, for example, if a bellows or the like is provided between the upper surface of the top plate portion 13 and the moving portion 100b, the gap between the top plate portion 13 and the moving portion 100b can be sealed.

[0177] An example of the process of the reduced-pressure drying treatment using the reduced-pressure drying apparatus 1D is the same as the reduced-pressure drying method in the first or second embodiment. However, in the first interval adjustment process, the first elevating unit 100 lowers the cooling member 41 to the lowered position H12 so that the interval between the substrate 9 and the cooling surface 40a is the first interval. Further, in the second interval adjustment process, the first elevating unit 100 raises the cooling member 41 to the raised position H11 so that the interval between the substrate 9 and the cooling surface 40a is the second interval. Further, as a modification, the seventh embodiment may employ the air supply mechanism 60M of the third embodiment ( Figure 17 ).

[0178] According to the seventh embodiment, the cooling member 41 is a member different from the chamber 10. Therefore, similarly to the sixth embodiment, the selectivity of the material of the cooling member 41 can be improved. Further, since the cooling surface 40a is the lower surface of the cooling member 41, the cooling unit 40 can cool the cooling surface 40a more efficiently, similarly to the sixth embodiment.

[0179] Further, in the seventh embodiment, even in the first state where the interval between the substrate 9 and the cooling surface 40a is the narrower first interval, the substrate 9 supported by the support portion 20 is surrounded by the four side rectifying plates 51. Therefore, in the first reduced-pressure process, the rectifying function of the four side rectifying plates 51 also acts on the upper space 10s1 between the substrate 9 and the cooling surface 40a. Therefore, the occurrence of drying unevenness can be further suppressed.

[0180] <8. Modification>

[0181] The present invention is not limited to the above-described various embodiments, and various changes and improvements can be made without departing from the gist of the present invention.

[0182] In the above-described embodiments, the first elevating unit 100 raises and lowers the support portion 20 or the cooling unit 40, but it is also possible to raise and lower both the support portion 20 and the cooling unit 40. In short, as long as the first elevating unit 100 raises and lowers at least one of the support portion 20 and the cooling surface 40a between the first state and the second state, in the first state, the interval between the substrate 9 supported by the support portion 20 and the cooling surface 40a is the first interval; in the second state, the interval between the substrate 9 supported by the support portion 20 and the cooling surface 40a is the second interval wider than the first interval.

[0183] In the above-described embodiments, for example, the chamber 10 has four exhaust ports 16a, 16b, 16c, 16d, but it is not limited thereto. For example, the number of exhaust ports that the chamber 10 has may be 1 to 3 or may be greater than or equal to 5. Further, for example, the independent valves Va, Vb, Vc, Vd may not be provided.

[0184] In the above-described embodiments, the reduced-pressure drying apparatuses 1, 1T, 1A to 1D utilize the action of reduced pressure to dry the coating film 90 on the substrate 9, but other actions can also be used in combination. For example, the action of heating can be used in combination.

[0185] In the above-described embodiments, the loading / unloading port 14 for the substrate 9 is provided on the side wall portion 12 of the chamber 10, but it is not limited thereto. For example, the following structure can be adopted: the four side wall portions 12 and the top plate portion 13 of the chamber 10 form an integrated lid portion that can be separated from the bottom plate portion 11 and moved upward to avoid. In this case, for example, the lid portion can be moved up and down by an opening / closing drive portion 16 or the like. Further, the chamber 10 can be selectively set to a state (sealed state) in which the lid portion contacts the bottom plate portion 11 via a sealing material such as an O-ring and seals the internal space 10s; a state (open state) in which the lid portion is separated upward from the bottom plate portion 11 and the internal space 10s is opened. Here, when the chamber 10 is in the open state, the substrate 9 can be loaded into the internal space 10s of the chamber 10 and the substrate 9 can be unloaded from the internal space 10s of the chamber 10. When the chamber 10 is in the closed state, the coating film 90 on the substrate 9 can be dried by reduced pressure by exhausting air from the internal space 10s and supplying air to the internal space 10s.

[0186] In the above-described embodiments, for example, the support portion 20 can have various forms. For example, the plurality of support plates 21 can be an integrated single support plate 21.

[0187] In the above-described embodiments, for example, the bottom surface rectifying plate 50 may be absent, or the side surface rectifying plate 51 may be absent.

[0188] In the above-described embodiments, for example, various operations in the reduced-pressure drying apparatuses 1, 1T, 1A to 1D can be started or ended according to the operation of the user on the input portion 804 or the signal input from an external device to the communication portion 806 or the like.

[0189] In the above-described embodiments, for example, at least a part of the functional structure implemented in the control portion 80 can also be implemented by hardware such as a dedicated electronic circuit.

[0190] In addition, it goes without saying that all or part of the above-described embodiments and various modification examples can be appropriately combined within a non-contradictory range.

Claims

1. A pressure-reducing drying device for drying a coating film applied to the upper surface of a substrate, wherein, Comprising: a chamber for accommodating the substrate; a support portion for supporting the substrate within the chamber; a cooling portion for cooling a cooling surface that faces the upper surface of the substrate supported by the support portion; a decompression mechanism for sucking gas from the chamber to reduce the pressure within the chamber; a gas supply mechanism for supplying gas into the chamber to increase the pressure within the chamber; and a control portion for controlling the gas supply mechanism such that, after supplying a predetermined amount of gas from the gas supply mechanism into the chamber in a decompressed state, an amount of gas is supplied from the gas supply mechanism to make the pressure within the chamber atmospheric pressure, wherein the decompression mechanism includes: a vacuum pump; and at least one vacuum valve located between the chamber and the vacuum pump, when supplying the predetermined amount of gas, the control portion controls the at least one vacuum valve to disconnect between the vacuum pump and the chamber, after supplying the predetermined amount of gas and before supplying an amount of gas from the gas supply mechanism to make the pressure within the chamber atmospheric pressure, the control portion controls the at least one vacuum valve to cause the vacuum pump to exhaust the chamber.

2. The decompression drying apparatus according to claim 1, wherein the gas supply mechanism includes: a gas supply source; a first buffer portion located between the chamber and the gas supply source; a first gas supply valve located between the chamber and the first buffer portion; and a second gas supply valve located between the first buffer portion and the gas supply source, in order to supply the predetermined amount of gas, the control portion controls the gas supply mechanism such that the second gas supply valve remains closed and the first gas supply valve is switched from the closed state to the open state.

3. The decompression drying apparatus according to claim 2, wherein the gas supply mechanism includes: a second buffer portion located between the second gas supply valve and the gas supply source; and a third gas supply valve located between the second buffer portion and the gas supply source, in order to supply the predetermined amount of gas, after the control portion controls the gas supply mechanism such that the second gas supply valve remains closed and the first gas supply valve is switched from the closed state to the open state, the control portion controls the gas supply mechanism such that the second gas supply valve is switched from the closed state to the open state.

4. A pressure-reducing drying method for drying a coating film applied to the upper surface of a substrate, wherein, Including: a first step of, while cooling a cooling surface that faces the upper surface of the substrate supported by a support portion within the chamber with an interval therebetween, reducing the pressure within the chamber by sucking gas from the chamber, causing the solvent to evaporate from the coating film on the substrate and condensing on the cooling surface; a second step of, after the first step, increasing the pressure within the chamber by supplying a predetermined amount of gas, causing the solvent on the cooling surface to evaporate to dry the cooling surface; and a third step of, after the second step, supplying an amount of gas to make the pressure within the chamber atmospheric pressure, when performing the second step, stopping the sucking of the gas within the chamber, after performing the second step and before performing the third step, restarting the sucking of the gas within the chamber.

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