Reduced pressure drying device and reduced pressure drying method

Abstract

The present invention provides a reduced pressure drying device and a reduced pressure drying method that can reduce the number of pumps in a reduced pressure drying device for drying a coating layer formed on the upper surface of a substrate by reducing pressure. The reduced pressure drying device (1) has a reduced pressure mechanism (20) comprising a first dedicated pump (51), a second dedicated pump (52), and a shared pump (55). The first dedicated pump (51) performs exhaust from a first chamber (11). The second dedicated pump (52) performs exhaust from a second chamber (12). The shared pump (55) can be switched between exhaust from the first chamber (11) and exhaust from the second chamber (12). Thus, the number of pumps can be reduced.

Description

Technical Field

[0001] The present invention relates to a reduced pressure drying device and a reduced pressure drying method for drying a coating layer formed on an upper surface of a substrate by reducing pressure. Background Art

[0002] In the past, in the manufacturing process of an organic electroluminescence (EL) display, a coating layer serving as a hole injection layer, a hole transport layer, or a light-emitting layer was formed on the upper surface of a substrate. The coating layer was partially coated on the upper surface of the substrate by an inkjet device. Furthermore, the substrate with the coating layer formed thereon was transported to a chamber of a reduced pressure drying device and subjected to a reduced pressure drying treatment. As a result, the solvent contained in the coating layer was vaporized and the coating layer was dried.

[0003] The reduced pressure drying device includes: a chamber for accommodating a substrate; and a decompression mechanism for sucking gas from the chamber. A conventional reduced pressure drying device is described in Patent Document 1, for example.

[0004] [Prior art literature]

[0005] [Patent Document]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2016-161146 Summary of the invention

[0007] [Problems to be solved by the invention]

[0008] However, the coating layer formed on the upper surface of the substrate sometimes contains multiple solvents with different boiling point pressures. In this case, the vacuum drying device needs to reduce the pressure in the chamber to a pressure suitable for each solvent at a decompression rate suitable for each solvent. In addition, in recent years, with the enlargement of substrates, the volume of the chamber for vacuum drying treatment has also increased. According to these circumstances, multiple vacuum pumps for sucking gas are sometimes connected to one chamber.

[0009] In addition, the reduced pressure drying apparatus may include a plurality of chambers. If a plurality of vacuum pumps are connected to each of the plurality of chambers, a large number of vacuum pumps are required.

[0010] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique capable of reducing the number of pumps in a reduced-pressure drying apparatus for drying a coating layer formed on an upper surface of a substrate by reducing pressure.

[0011] [Technical means to solve the problem]

[0012] In order to solve the above-mentioned problem, the first invention of the present application is a reduced-pressure drying device for drying a coating layer formed on the upper surface of a substrate by reducing pressure, the reduced-pressure drying device comprising: a first chamber and a second chamber capable of accommodating a substrate; and a reduced-pressure mechanism for exhausting gas from the first chamber and the second chamber, the reduced-pressure mechanism comprising: a first dedicated pump connected to the first chamber; a second dedicated pump connected to the second chamber; a shared pump; a first exhaust path connecting the first chamber to the shared pump; a second exhaust path connecting the second chamber to the shared pump; and a shared switching section for switching between a closed state, a first open state, and a second open state, the closed state being to close both the first exhaust path and the second exhaust path, the first open state being to close the second exhaust path and to open the first exhaust path, and the second open state being to close the first exhaust path and to open the second exhaust path.

[0013] The second invention of the present application is a reduced-pressure drying device according to the first invention, and further includes: a control unit that controls the shared switching unit, wherein the control unit a) sets the shared switching unit to the closed state, b) sets the shared switching unit to the first open state after the process a), and c) sets the shared switching unit to the second open state after the process b).

[0014] A third invention of the present application is the reduced-pressure drying device according to the first invention or the second invention, wherein the reduced-pressure mechanism has a plurality of the shared pumps.

[0015] The fourth invention of the present application is a reduced-pressure drying device according to any one of the first to third inventions, wherein the reduced-pressure mechanism further comprises: a first high vacuum pump connected to the first chamber; and a second high vacuum pump connected to the second chamber.

[0016] The fifth invention of the present application is a reduced-pressure drying device according to the fourth invention, wherein the reduced-pressure mechanism further comprises: a first switching unit for switching between a state in which the first dedicated pump is connected to the first chamber and a state in which the first dedicated pump is connected to the downstream side of the first high vacuum pump; and a second switching unit for switching between a state in which the second dedicated pump is connected to the second chamber and a state in which the second dedicated pump is connected to the downstream side of the second high vacuum pump.

[0017] The sixth invention of the present application is a reduced-pressure drying method for drying a coating layer formed on the upper surface of a substrate by reducing pressure, the reduced-pressure drying method comprising: a) a process of exhausting gas from a first chamber by a first dedicated pump; b) a process of exhausting gas from a second chamber by a second dedicated pump; c) after the process a), a process of exhausting gas from the first chamber by the first dedicated pump and a common pump; and d) after the process b) and the process c), a process of exhausting gas from the second chamber by the second dedicated pump and the common pump.

[0018] The seventh invention of the present application is a reduced-pressure drying method according to the sixth invention, wherein in the process c), gas is exhausted from the first chamber through the first dedicated pump and the multiple shared pumps, and in the process d), gas is exhausted from the second chamber through the second dedicated pump and the multiple shared pumps.

[0019] The eighth invention of the present application is a reduced-pressure drying method according to the sixth invention or the seventh invention, and further comprises: e) a process of exhausting gas from the first chamber by a first high vacuum pump after the process c); and f) a process of exhausting gas from the second chamber by a second high vacuum pump after the process d).

[0020] The ninth invention of the present application is a reduced-pressure drying method according to the eighth invention, wherein in the process e), exhaust based on the first dedicated pump is performed on the downstream side of the first high vacuum pump, and in the process f), exhaust based on the second dedicated pump is performed on the downstream side of the second high vacuum pump.

[0021] [Effects of the Invention]

[0022] According to the first to fifth inventions of the present application, when the shared switching portion is set to a closed state, it is possible to exhaust air from the first chamber using only the first dedicated pump, and to exhaust air from the second chamber using only the second dedicated pump. In addition, when the shared switching portion is set to a first open state, it is possible to exhaust air from the first chamber using the first dedicated pump and the shared pump. In addition, when the shared switching portion is set to a second open state, it is possible to exhaust air from the second chamber using the second dedicated pump and the shared pump. In this way, the shared pump can be used by switching between exhausting air from the first chamber and exhausting air from the second chamber. Thus, the number of pumps can be reduced.

[0023] In particular, according to the second invention of the present application, first, in step a), exhaust is performed at a low speed from the first chamber using only the first dedicated pump, and exhaust is performed at a low speed from the second chamber using only the second dedicated pump. Then, in step b), the first chamber is depressurized to a lower pressure by using the first dedicated pump and the shared pump. Thereafter, in step c), the second chamber is depressurized to a lower pressure by using the second dedicated pump and the shared pump. Thus, the first chamber and the second chamber can be depressurized to a low pressure while suppressing the number of pumps.

[0024] In particular, according to the third invention of the present application, the suction force when a dedicated pump and a shared pump are used together can be further improved.

[0025] In particular, according to the fourth invention of the present application, the first chamber can be depressurized to a lower pressure by using the first high vacuum pump, and the second chamber can be depressurized to a lower pressure by using the second high vacuum pump.

[0026] In particular, according to the fifth invention of the present application, the first dedicated pump is used as an auxiliary pump for the first high vacuum pump, and the second dedicated pump is used as an auxiliary pump for the second high vacuum pump, thereby further reducing the number of pumps.

[0027] In addition, according to the sixth to ninth inventions of the present application, in step c), the common pump is used for exhausting the first chamber. In step d), the common pump is used for exhausting the second chamber. In this way, the common pump is switched between exhausting the first chamber and exhausting the second chamber. Thus, the number of pumps can be reduced.

[0028] In particular, according to the seventh invention of the present application, the suction force in step c) and step d) can be further improved.

[0029] In particular, according to the eighth invention of the present application, the first chamber can be depressurized to a lower pressure by using the first high vacuum pump, and the second chamber can be depressurized to a lower pressure by using the second high vacuum pump.

[0030] In particular, according to the ninth invention of the present application, the first dedicated pump is used as an auxiliary pump for the first high vacuum pump, and the second dedicated pump is used as an auxiliary pump for the second high vacuum pump, thereby further reducing the number of pumps. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a diagram showing the structure of a reduced-pressure drying apparatus.

[0032] Figure 2 It is a control block diagram of a vacuum drying device.

[0033] Figure 3: is a flowchart showing the flow of the reduced pressure drying process.

[0034] Figure 4 This is a graph showing changes in the gas pressure in the chamber during the reduced pressure drying process.

[0035] Figure 5 It is a timing chart showing the timing of executing the first decompression step, the second decompression step, the third decompression step, and the gas supply step in the four chambers.

[0036] Explanation of symbols

[0037] 1: Vacuum drying device

[0038] 11: First chamber (chamber)

[0039] 12: Second chamber (chamber)

[0040] 13: The third chamber (chamber)

[0041] 14: The fourth chamber (chamber)

[0042] 20: Pressure relief mechanism

[0043] 21: First independent piping

[0044] 22: Second independent piping

[0045] 23: The third independent piping

[0046] 24: Fourth independent piping

[0047] 31: First dedicated pipe

[0048] 32: Second dedicated piping

[0049] 33: The third dedicated pipe

[0050] 34: Fourth dedicated piping

[0051] 35: Total piping

[0052] 41: First relay piping

[0053] 42: Second relay piping

[0054] 43: Third relay piping

[0055] 44: Fourth relay piping

[0056] 51: First special pump

[0057] 52: Second dedicated pump

[0058] 53: The third special pump

[0059] 54: The fourth special pump

[0060] 55: Total pump

[0061] 61: The first high vacuum pump (high vacuum pump)

[0062] 62: Second high vacuum pump (high vacuum pump)

[0063] 63: The third high vacuum pump (high vacuum pump)

[0064] 64: Fourth high vacuum pump (high vacuum pump)

[0065] 70: Gas supply mechanism

[0066] 71: First air supply unit

[0067] 72: Second air supply unit

[0068] 73: The third air supply department

[0069] 74: The fourth air supply unit

[0070] 80: Control Department

[0071] 81: Processor

[0072] 82: Memory

[0073] 83: Storage

[0074] 351: First branch management

[0075] 352: Second branch management

[0076] 353: Third branch management

[0077] 354: Fourth Branch Administration

[0078] P0: atmospheric pressure

[0079] P1: First pressure

[0080] P2: Second pressure

[0081] P3: The third pressure

[0082] Pa: boiling point pressure

[0083] Pb: boiling point pressure

[0084] S0: Process

[0085] S1: First decompression step

[0086] S2: Second decompression step

[0087] S3: The third decompression step

[0088] S4: Gas supply process

[0089] S5: Process

[0090] t0~t4: time

[0091] V11: First independent valve (valve)

[0092] V12: Second independent valve (valve)

[0093] V13: The third independent valve (valve)

[0094] V14: Fourth independent valve (valve)

[0095] V21: First branch valve (branch valve) (valve)

[0096] V22: Second branch valve (branch valve) (valve)

[0097] V23: The third branch valve (branch valve) (valve)

[0098] V24: The fourth branch valve (branch valve) (valve)

[0099] V31: First opening and closing valve (valve)

[0100] V32: Second on-off valve (valve)

[0101] V33: The third on-off valve (valve)

[0102] V34: Fourth on-off valve (valve)

[0103] V41: First relay valve (valve)

[0104] V42: Second relay valve (valve)

[0105] V43: Third relay valve (valve)

[0106] V44: Fourth relay valve (valve)

[0107] V51: First air supply valve (valve)

[0108] V52: Second air supply valve (valve)

[0109] V53: The third air supply valve (valve)

[0110] V54: Fourth air supply valve (valve)

[0111] Δt: delay time DETAILED DESCRIPTION

[0112] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0113] <1. Regarding the structure of the vacuum drying device>

[0114] Figure 1 1 is a diagram showing a structure of a reduced-pressure drying apparatus 1 according to an embodiment of the present invention. The reduced-pressure drying apparatus 1 is an apparatus for performing a reduced-pressure drying process on a substrate in a manufacturing process of an organic EL display.

[0115] The substrate is, for example, a rectangular glass substrate. A coating layer containing an organic material and a solvent is pre-formed on the upper surface of the substrate. The coating layer is formed according to a circuit pattern using an inkjet device in a coating process before the reduced pressure drying process. Therefore, the upper surface of the substrate has a portion covered by the coating layer and a portion exposed from the coating layer. The coating layer is dried in the reduced pressure drying device 1 to become a hole injection layer, a hole transport layer, or a light-emitting layer of the organic EL display.

[0116] like Figure 1 As shown, the reduced pressure drying device 1 of this embodiment includes: a first chamber 11, a second chamber 12, a third chamber 13, and a fourth chamber 14. The first chamber 11, the second chamber 12, the third chamber 13, and the fourth chamber 14 are pressure-resistant containers capable of accommodating substrates. The first chamber 11, the second chamber 12, the third chamber 13, and the fourth chamber 14 have the same structure. A stage is provided inside each chamber 11, 12, 13, and 14. The substrates are moved into the interior of each chamber 11, 12, 13, and 14 one by one, and supported on the stage in a horizontal posture.

[0117] Furthermore, the reduced-pressure drying apparatus 1 includes a reduced-pressure mechanism 20. The reduced-pressure mechanism 20 is a mechanism for exhausting gas from the internal space of each chamber 11, 12, 13, 14 to reduce the gas pressure in the chambers 11, 12, 13, 14.

[0118] like Figure 1 As shown, the pressure reducing mechanism 20 comprises: a first independent piping 21, a second independent piping 22, a third independent piping 23, a fourth independent piping 24, a first dedicated piping 31, a second dedicated piping 32, a third dedicated piping 33, a fourth dedicated piping 34, a shared piping 35, a first relay piping 41, a second relay piping 42, a third relay piping 43, a fourth relay piping 44, a first dedicated pump 51, a second dedicated pump 52, a third dedicated pump 53, a fourth dedicated pump 54, a plurality of shared pumps 55, a first high vacuum pump 61, a second high vacuum pump 62, a third high vacuum pump 63, and a fourth high vacuum pump 64.

[0119] A plurality of exhaust ports are provided at the bottom of the first chamber 11. The upstream end of the first independent pipe 21 branches into a plurality of branches, which are connected to the plurality of exhaust ports of the first chamber 11. The downstream end of the first independent pipe 21 is connected to the upstream end of the first dedicated pipe 31. The downstream end of the first dedicated pipe 31 is connected to the first dedicated pump 51. That is, the first dedicated pump 51 is connected to the first chamber 11 via the first dedicated pipe 31 and the first independent pipe 21. Figure 1 In the embodiment, the upstream end of the first independent pipe 21 branches into two and is connected to two exhaust ports of the first chamber 11. However, the exhaust ports of the first chamber 11 connected to the first independent pipe 21 are not limited to two. The same is true for the second chamber 12 and the second independent pipe 22, the third chamber 13 and the third independent pipe 23, and the fourth chamber 14 and the fourth independent pipe 24.

[0120] A first independent valve V11 is provided on the path of the first independent pipe 21. When the first independent valve V11 is opened and the first dedicated pump 51 is driven, the gas in the first chamber 11 is discharged to the outside through the first independent pipe 21 and the first dedicated pipe 31. Thus, the gas pressure in the first chamber 11 can be reduced.

[0121] A plurality of exhaust ports are provided at the bottom of the second chamber 12. The end portion on the upstream side of the second independent pipe 22 is branched into a plurality of branches, and connected to the plurality of exhaust ports of the second chamber 12. The end portion on the downstream side of the second independent pipe 22 is connected to the end portion on the upstream side of the second dedicated pipe 32. The end portion on the downstream side of the second dedicated pipe 32 is connected to the second dedicated pump 52. That is, the second dedicated pump 52 is connected to the second chamber 12 via the second dedicated pipe 32 and the second independent pipe 22.

[0122] A second independent valve V12 is provided on the path of the second independent pipe 22. When the second independent valve V12 is opened and the second dedicated pump 52 is driven, the gas in the second chamber 12 is discharged to the outside through the second independent pipe 22 and the second dedicated pipe 32. Thus, the gas pressure in the second chamber 12 can be reduced.

[0123] A plurality of exhaust ports are provided at the bottom of the third chamber 13. The end portion on the upstream side of the third independent pipe 23 is branched into a plurality of branches, and connected to the plurality of exhaust ports of the third chamber 13. The end portion on the downstream side of the third independent pipe 23 is connected to the end portion on the upstream side of the third dedicated pipe 33. The end portion on the downstream side of the third dedicated pipe 33 is connected to the third dedicated pump 53. That is, the third dedicated pump 53 is connected to the third chamber 13 via the third dedicated pipe 33 and the third independent pipe 23.

[0124] A third independent valve V13 is provided on the path of the third independent pipe 23. When the third independent valve V13 is opened and the third dedicated pump 53 is driven, the gas in the third chamber 13 is discharged to the outside through the third independent pipe 23 and the third dedicated pipe 33. Thus, the gas pressure in the third chamber 13 can be reduced.

[0125] A plurality of exhaust ports are provided at the bottom of the fourth chamber 14. The upstream end of the fourth independent pipe 24 is branched into a plurality of branches, which are connected to the plurality of exhaust ports of the fourth chamber 14. The downstream end of the fourth independent pipe 24 is connected to the upstream end of the fourth dedicated pipe 34. The downstream end of the fourth dedicated pipe 34 is connected to the fourth dedicated pump 54. That is, the fourth dedicated pump 54 is connected to the fourth chamber 14 via the fourth dedicated pipe 34 and the fourth independent pipe 24.

[0126] A fourth independent valve V14 is provided on the path of the fourth independent pipe 24. When the fourth independent valve V14 is opened and the fourth dedicated pump 54 is driven, the gas in the fourth chamber 14 is discharged to the outside through the fourth independent pipe 24 and the fourth dedicated pipe 34. Thus, the gas pressure in the fourth chamber 14 can be reduced.

[0127] The shared pipe 35 is a pipe used when driving the shared pump 55. The end portion on the upstream side of the shared pipe 35 is branched into four pipes, namely, a first branch pipe 351, a second branch pipe 352, a third branch pipe 353, and a fourth branch pipe 354. The first branch pipe 351 is connected to the end portion on the downstream side of the first independent pipe 21. The second branch pipe 352 is connected to the end portion on the downstream side of the second independent pipe 22. The third branch pipe 353 is connected to the end portion on the downstream side of the third independent pipe 23. The fourth branch pipe 354 is connected to the end portion on the downstream side of the fourth independent pipe 24. The end portion on the downstream side of the shared pipe 35 is branched into a plurality of pipes, each of which is connected to a plurality of shared pumps 55.

[0128] The first independent pipe 21, the first branch pipe 351, and the shared pipe 35 constitute a "first exhaust path" that connects the first chamber 11 to the plurality of shared pumps 55. The second independent pipe 22, the second branch pipe 352, and the shared pipe 35 constitute a "second exhaust path" that connects the second chamber 12 to the plurality of shared pumps 55. The third independent pipe 23, the third branch pipe 353, and the shared pipe 35 constitute a "third exhaust path" that connects the third chamber 13 to the plurality of shared pumps 55. The fourth independent pipe 24, the fourth branch pipe 354, and the shared pipe 35 constitute a "fourth exhaust path" that connects the fourth chamber 14 to the plurality of shared pumps 55.

[0129] The first branch pipe 351 is provided with a first branch valve V21. The second branch pipe 352 is provided with a second branch valve V22. The third branch pipe 353 is provided with a third branch valve V23. The fourth branch pipe 354 is provided with a fourth branch valve V24.

[0130] When the first independent valve V11 and the first branch valve V21 are opened, the other branch valves V22, V23, and V24 are closed, and the first dedicated pump 51 and the shared pump 55 are operated, the gas in the first chamber 11 is discharged to the outside through the two paths of the first dedicated pipe 31 and the shared pipe 35. Thus, the gas pressure in the first chamber 11 can be reduced to a lower pressure than when only the first dedicated pump 51 is used.

[0131] When the second independent valve V12 and the second branch valve V22 are opened, the other branch valves V21, V23, and V24 are closed, and the second dedicated pump 52 and the shared pump 55 are operated, the gas in the second chamber 12 is discharged to the outside through the two paths of the second dedicated pipe 32 and the shared pipe 35. Thus, the gas pressure in the second chamber 12 can be reduced to a lower pressure than when only the second dedicated pump 52 is used.

[0132] When the third independent valve V13 and the third branch valve V23 are opened, the other branch valves V21, V22, and V24 are closed, and the third dedicated pump 53 and the shared pump 55 are operated, the gas in the third chamber 13 is discharged to the outside through the two paths of the third dedicated pipe 33 and the shared pipe 35. Thus, the gas pressure in the third chamber 13 can be reduced to a lower pressure than when only the third dedicated pump 53 is used.

[0133] When the fourth independent valve V14 and the fourth branch valve V24 are opened, the other branch valves V21, V22, and V23 are closed, and the fourth dedicated pump 54 and the shared pump 55 are operated, the gas in the fourth chamber 14 is discharged to the outside through the two paths of the fourth dedicated pipe 34 and the shared pipe 35. Thus, the gas pressure in the fourth chamber 14 can be reduced to a lower pressure than when only the fourth dedicated pump 54 is used.

[0134] Furthermore, when the first branch valve V21 , the second branch valve V22 , the third branch valve V23 , and the fourth branch valve V24 are all closed, the plurality of shared pumps 55 are not connected to any of the chambers 11 to 14 .

[0135] That is, the first branch valve V21, the second branch valve V22, the third branch valve V23, and the fourth branch valve V24 constitute a "common switching part", and the "common switching part" switches between a "closed state", a "first open state", a "second open state", a "third open state", and a "fourth open state", and the "closed state" is to close the "first exhaust path", "second exhaust path", "third exhaust path", and "fourth exhaust path", the "first open state" is to open only the "first exhaust path" and close other exhaust paths, the "second open state" is to open only the "second exhaust path" and close other exhaust paths, the "third open state" is to open only the "third exhaust path" and close other exhaust paths, and the "fourth open state" is to open only the "fourth exhaust path" and close other exhaust paths.

[0136] In the "closed state", the first chamber 11 can be exhausted using only the first dedicated pump 51, the second chamber 12 can be exhausted using only the second dedicated pump 52, the third chamber 13 can be exhausted using only the third dedicated pump 53, and the fourth chamber 14 can be exhausted using only the fourth dedicated pump 54.

[0137] In the "first open state", the first dedicated pump 51 and the plurality of shared pumps 55 can be used to exhaust air from the first chamber 11. In the "second open state", the second dedicated pump 52 and the plurality of shared pumps 55 can be used to exhaust air from the second chamber 12. In the "third open state", the third dedicated pump 53 and the plurality of shared pumps 55 can be used to exhaust air from the third chamber 13. In the "fourth open state", the fourth dedicated pump 54 and the plurality of shared pumps 55 can be used to exhaust air from the fourth chamber 14.

[0138] Thus, in the reduced pressure drying device 1 of the present embodiment, the plurality of shared pumps 55 can be switched and used between exhaust from the first chamber 11, exhaust from the second chamber 12, exhaust from the third chamber 13, and exhaust from the fourth chamber 14. That is, the plurality of shared pumps 55 can be used for exhausting any of the chambers 11, 12, 13, and 14. Thus, the number of pumps included in the reduced pressure mechanism 20 can be reduced.

[0139] The first dedicated pump 51, the second dedicated pump 52, the third dedicated pump 53, the fourth dedicated pump 54, and the plurality of shared pumps 55 are vacuum pumps capable of reducing the pressure in the chambers 11 to 14 from the atmospheric pressure. The first dedicated pump 51, the second dedicated pump 52, the third dedicated pump 53, the fourth dedicated pump 54, and the plurality of shared pumps 55 are dry pumps that do not use a liquid such as oil for sealing the vacuum chamber, for example.

[0140] The first dedicated pump 51, the second dedicated pump 52, the third dedicated pump 53, and the fourth dedicated pump 54 use vacuum pumps having the same suction force. The shared pump 55 may be a vacuum pump having the same suction force as the first dedicated pump 51, the second dedicated pump 52, the third dedicated pump 53, and the fourth dedicated pump 54, or may be a vacuum pump having a different suction force. For example, the shared pump 55 may be a vacuum pump having a higher suction force than the first dedicated pump 51, the second dedicated pump 52, the third dedicated pump 53, and the fourth dedicated pump 54.

[0141] The first high vacuum pump 61, the second high vacuum pump 62, the third high vacuum pump 63, and the fourth high vacuum pump 64 are pumps having a suction force stronger than the first dedicated pump 51, the second dedicated pump 52, the third dedicated pump 53, the fourth dedicated pump 54, and the plurality of shared pumps 55. The first high vacuum pump 61, the second high vacuum pump 62, the third high vacuum pump 63, and the fourth high vacuum pump 64 use, for example, turbomolecular pumps.

[0142] The first high vacuum pump 61 is connected to an exhaust port provided at the bottom of the first chamber 11 via the first opening and closing valve V31. In addition, the first high vacuum pump 61 is connected to the first dedicated pipe 31 via the first relay pipe 41. A first relay valve V41 is provided on the path of the first relay pipe 41. When the first independent valve V11 is closed, the first opening and closing valve V31 and the first relay valve V41 are opened, and the first dedicated pump 51 and the first high vacuum pump 61 are operated, the air pressure in the first chamber 11, which has been depressurized by the first dedicated pump 51 and the shared pump 55, can be reduced to a lower pressure.

[0143] A high vacuum pump such as a turbomolecular pump needs to be exhausted by an auxiliary pump on the downstream side of the exhaust path. In the present embodiment, the first dedicated pump 51 is used as an auxiliary pump for the first high vacuum pump 61. If so, there is no need to provide an auxiliary pump independently of the first dedicated pump 51. Therefore, the number of pumps possessed by the decompression mechanism 20 can be further reduced. The first independent valve V11 and the first relay valve V41 constitute a "first switching unit", which switches between a state in which the first dedicated pump 51 is directly connected to the first chamber 11 and a state in which the first dedicated pump 51 is connected to the downstream side of the first high vacuum pump 61.

[0144] The second high vacuum pump 62 is connected to an exhaust port provided at the bottom of the second chamber 12 via the second opening and closing valve V32. In addition, the second high vacuum pump 62 is connected to the second dedicated pipe 32 via the second relay pipe 42. A second relay valve V42 is provided on the path of the second relay pipe 42. When the second independent valve V12 is closed, the second opening and closing valve V32 and the second relay valve V42 are opened, and the second dedicated pump 52 and the second high vacuum pump 62 are operated, the air pressure in the second chamber 12, which has been depressurized by the second dedicated pump 52 and the shared pump 55, can be reduced to a lower pressure.

[0145] In the present embodiment, the second dedicated pump 52 is used as an auxiliary pump for the second high vacuum pump 62. In this way, there is no need to provide an auxiliary pump independently of the second dedicated pump 52. Therefore, the number of pumps included in the decompression mechanism 20 can be further reduced. The second independent valve V12 and the second relay valve V42 constitute a "second switching unit" that switches between a state in which the second dedicated pump 52 is directly connected to the second chamber 12 and a state in which the second dedicated pump 52 is connected to the downstream side of the second high vacuum pump 62.

[0146] The third high vacuum pump 63 is connected to an exhaust port provided at the bottom of the third chamber 13 via the third opening and closing valve V33. In addition, the third high vacuum pump 63 and the third dedicated pipe 33 are connected via the third relay pipe 43. A third relay valve V43 is provided on the path of the third relay pipe 43. When the third independent valve V13 is closed, the third opening and closing valve V33 and the third relay valve V43 are opened, and the third dedicated pump 53 and the third high vacuum pump 63 are operated, the air pressure in the third chamber 13, which has been depressurized by the third dedicated pump 53 and the shared pump 55, can be reduced to a lower pressure.

[0147] In the present embodiment, the third dedicated pump 53 is used as an auxiliary pump for the third high vacuum pump 63. In this way, there is no need to provide an auxiliary pump independently of the third dedicated pump 53. Therefore, the number of pumps of the decompression mechanism 20 can be further reduced. The third independent valve V13 and the third relay valve V43 constitute a "third switching unit" that switches between a state in which the third dedicated pump 53 is directly connected to the third chamber 13 and a state in which the third dedicated pump 53 is connected to the downstream side of the third high vacuum pump 63.

[0148] The fourth high vacuum pump 64 is connected to an exhaust port provided at the bottom of the fourth chamber 14 via the fourth opening and closing valve V34. In addition, the fourth high vacuum pump 64 is connected to the fourth dedicated pipe 34 via the fourth relay pipe 44. A fourth relay valve V44 is provided on the path of the fourth relay pipe 44. When the fourth independent valve V14 is closed, the fourth opening and closing valve V34 and the fourth relay valve V44 are opened, and the fourth dedicated pump 54 and the fourth high vacuum pump 64 are operated, the air pressure in the fourth chamber 14, which has been depressurized by the fourth dedicated pump 54 and the shared pump 55, can be reduced to a lower pressure.

[0149] In the present embodiment, the fourth dedicated pump 54 is used as an auxiliary pump for the fourth high vacuum pump 64. If so, there is no need to provide an auxiliary pump independently of the fourth dedicated pump 54. Therefore, the number of pumps of the decompression mechanism 20 can be further reduced. The fourth independent valve V14 and the fourth relay valve V44 constitute a "fourth switching unit" that switches between a state in which the fourth dedicated pump 54 is directly connected to the fourth chamber 14 and a state in which the fourth dedicated pump 54 is connected to the downstream side of the fourth high vacuum pump 64.

[0150] In addition, the reduced pressure drying device 1 includes a gas supply mechanism 70. The gas supply mechanism 70 is a mechanism for supplying gas to the internal space of each chamber 11, 12, 13, 14 at the end of the reduced pressure drying process to restore the gas pressure in the chambers 11, 12, 13, 14 to atmospheric pressure. Figure 1 As shown, the air supply mechanism 70 includes a first air supply portion 71 , a second air supply portion 72 , a third air supply portion 73 , and a fourth air supply portion 74 .

[0151] The first gas supply unit 71 is connected to the first chamber 11 via the first gas supply valve V51. When the first gas supply valve V51 is opened, gas is supplied from the first gas supply unit 71 into the first chamber 11. Thus, the gas pressure in the first chamber 11 can be increased. The second gas supply unit 72 is connected to the second chamber 12 via the second gas supply valve V52. When the second gas supply valve V52 is opened, gas is supplied from the second gas supply unit 72 into the second chamber 12. Thus, the gas pressure in the second chamber 12 can be increased.

[0152] The third gas supply unit 73 is connected to the third chamber 13 via the third gas supply valve V53. When the third gas supply valve V53 is opened, gas is supplied from the third gas supply unit 73 to the third chamber 13. Thus, the gas pressure in the third chamber 13 can be increased. The fourth gas supply unit 74 is connected to the fourth chamber 14 via the fourth gas supply valve V54. When the fourth gas supply valve V54 is opened, gas is supplied from the fourth gas supply unit 74 to the fourth chamber 14. Thus, the gas pressure in the fourth chamber 14 can be increased.

[0153] Furthermore, the gas supplied from the first gas supply part 71 , the second gas supply part 72 , the third gas supply part 73 , and the fourth gas supply part 74 may be an inert gas such as nitrogen, or may be clean dry air.

[0154] Furthermore, the reduced-pressure drying apparatus 1 includes a control unit 80. The control unit 80 is a means for performing operation control on each unit of the reduced-pressure drying apparatus 1. Figure 2 is a control block diagram of the reduced pressure drying device 1. Figure 2 As shown, the control unit 80 is composed of a computer having a processor 81 such as a central processing unit (CPU), a memory 82 such as a random access memory (RAM), and a storage unit 83 such as a hard disk drive. The storage unit 83 stores a computer program and various data for executing the reduced pressure drying process.

[0155] In addition, if Figure 2 As shown, the control unit 80 is electrically connected to the first dedicated pump 51, the second dedicated pump 52, the third dedicated pump 53, the fourth dedicated pump 54, the plurality of shared pumps 55, the first high vacuum pump 61, the second high vacuum pump 62, the third high vacuum pump 63, the fourth high vacuum pump 64, and the plurality of valves V11 to V14, V21 to V24, V31 to V34, V41 to V44, and V51 to V54. The control unit 80 reads the computer program and various data from the storage unit 83 to the memory 82, and causes the processor 81 to perform calculation processing according to the computer program and data, thereby controlling the operation of the above-mentioned parts.

[0156] <2. Flow of vacuum drying in one chamber>

[0157] Next, a description will be given of a reduced pressure drying process of a substrate using the reduced pressure drying apparatus 1. First, the flow of the reduced pressure drying process in the first chamber 11 will be described below. Figure 3 : is a flowchart showing the flow of the reduced pressure drying process in the first chamber 11 . Figure 4 : is a graph showing the change of the gas pressure in the first chamber 11 during the reduced pressure drying process. Figure 4 The horizontal axis represents time. Figure 4 The vertical axis represents the gas pressure in the first chamber 11 .

[0158] When performing the reduced pressure drying process, first, the substrate is moved into the first chamber 11 ( Figure 3 The substrate is loaded into the first chamber 11 through an unillustrated loading / unloading port. Then, the substrate is placed on the upper surface of the stage in the first chamber 11. Thereafter, the loading / unloading port of the first chamber 11 is closed. Thus, the substrate is contained in the sealed space in the first chamber 11.

[0159] An undried coating layer is formed on the upper surface of the substrate. In this embodiment, the coating layer contains two solvents, namely, a first solvent and a second solvent. Furthermore, the boiling point pressure Pb of the second solvent is lower than the boiling point pressure Pa of the first solvent.

[0160] When the substrate is carried into the first chamber 11 , all of the plurality of valves V11 to V14 , V21 to V24 , V31 to V34 , V41 to V44 , and V51 to V54 are closed.

[0161] The vacuum drying device 1 first performs the first vacuum step S1 in the first chamber 11. In the first vacuum step S1, the control unit 80 opens the first independent valve V11 and operates the first dedicated pump 51. Thus, the gas from the first chamber 11 starts to be discharged. The control unit 80 continues the first vacuum step for a preset time. Figure 4 As shown in FIG. 1 , from time t0 to time t1, the pressure in the first chamber 11 is gradually reduced from the atmospheric pressure P0 to the first pressure P1.

[0162] When the first decompression step S1 of the specified time is completed, the decompression drying device 1 then performs the second decompression step S2 in the first chamber 11. In the second decompression step S2, the control unit 80 maintains the first independent valve V11 in an open state, and continues to drive the first dedicated pump 51, while opening the first branch valve V21 and operating the multiple shared pumps 55. That is, in the second decompression step S2, the first dedicated pump 51 and the multiple shared pumps 55 are used simultaneously. As a result, the gas is exhausted from the first chamber 11 with a suction force stronger than that in the first decompression step S1. As a result, as Figure 4 As shown in the period from time t1 to time t2, the gas pressure in the first chamber 11 drops rapidly from the first pressure P1 to the second pressure P2.

[0163] The boiling point pressure Pa of the first solvent contained in the coating layer formed on the upper surface of the substrate is lower than the first pressure P1 and higher than the second pressure P2. Therefore, in the second decompression step S2, the gas pressure in the first chamber 11 is reduced to the second pressure P2, thereby completing the vaporization of the first solvent.

[0164] When the second decompression step S2 of the specified time is completed, the decompression drying device 1 then performs the third decompression step S3 in the first chamber 11. In the third decompression step S3, the control unit 80 stops the common pump 55 and closes the first independent valve V11 and the first branch valve V21. In addition, the control unit 80 opens the first on-off valve V31 and the first relay valve V41. Then, the control unit 80 continues the operation of the first dedicated pump 51 and operates the first high vacuum pump 61. As a result, the gas is exhausted from the first chamber 11 with a stronger suction force than that in the second decompression step S2. As a result, as Figure 4 As shown in the period from time t2 to time t3, the gas pressure in the first chamber 11 decreases from the second pressure P2 to the third pressure P3.

[0165] The boiling point pressure Pb of the second solvent contained in the coating layer formed on the upper surface of the substrate is lower than the second pressure P2 and higher than the third pressure P3. Therefore, in the third decompression step S3, the gas pressure in the first chamber 11 is reduced to the third pressure P3, thereby completing the gasification of the second solvent.

[0166] When the third decompression step S3 of the predetermined time is completed, the decompression drying device 1 then performs the gas supply step S4 in the first chamber 11. In the gas supply step S4, the control unit 80 stops the first dedicated pump 51 and the first high vacuum pump 61, and closes the first opening and closing valve V31 and the first relay valve V41. Then, the control unit 80 opens the first gas supply valve V51. Thus, gas is supplied from the first gas supply unit 71 to the first chamber 11. Thus, as shown in FIG. Figure 4 As in the period from time t3 to time t4, the gas pressure in the first chamber 11 rises again from the third pressure P3 to the atmospheric pressure P0.

[0167] When the air pressure in the first chamber 11 reaches the atmospheric pressure P0, the control unit 80 closes the first air supply valve V51. Thereafter, the loading / unloading port of the first chamber 11 is opened, and the substrate is unloaded from the first chamber 11 through the loading / unloading port ( Figure 3 Based on the above, the reduced pressure drying process of one substrate in the first chamber 11 is completed.

[0168] <3. Flow of vacuum drying in four chambers>

[0169] As described above, the decompression drying process in the first chamber 11 is performed by the control unit 80 controlling the first dedicated pump 51, the plurality of shared pumps 55, the first high vacuum pump 61, the first independent valve V11, the first branch valve V21, the first opening and closing valve V31, the first relay valve V41, and the first air supply valve V51. Thus, the first decompression step S1, the second decompression step S2, the third decompression step S3, and the air supply step S4 are performed.

[0170] Similarly, the reduced pressure drying process in the second chamber 12 is also performed by controlling the second dedicated pump 52, the plurality of shared pumps 55, the second high vacuum pump 62, the second independent valve V12, the second branch valve V22, the second opening and closing valve V32, the second relay valve V42, and the second air supply valve V52 by the control unit 80. Thus, the same processes as the first reduced pressure step S1, the second reduced pressure step S2, the third reduced pressure step S3, and the air supply step S4 are performed.

[0171] In addition, the decompression drying process in the third chamber 13 is also performed by controlling the third dedicated pump 53, the plurality of shared pumps 55, the third high vacuum pump 63, the third independent valve V13, the third branch valve V23, the third opening and closing valve V33, the third relay valve V43, and the third air supply valve V53 by the control unit 80. Thus, the same process as the first decompression step S1, the second decompression step S2, the third decompression step S3, and the air supply step S4 is performed.

[0172] In addition, the decompression drying process in the fourth chamber 14 is also performed by controlling the fourth dedicated pump 54, the plurality of shared pumps 55, the fourth high vacuum pump 64, the fourth independent valve V14, the fourth branch valve V24, the fourth opening and closing valve V34, the fourth relay valve V44, and the fourth air supply valve V54 by the control unit 80. Thus, the same process as the first decompression step S1, the second decompression step S2, the third decompression step S3, and the air supply step S4 is performed.

[0173] However, the timings of executing the steps in the first chamber 11 , the second chamber 12 , the third chamber 13 , and the fourth chamber 14 are slightly shifted. Figure 5 It is a timing chart showing the timing of performing the first decompression step S1 , the second decompression step S2 , the third decompression step S3 , and the gas supply step S4 in the first chamber 11 , the second chamber 12 , the third chamber 13 , and the fourth chamber 14 .

[0174] like Figure 5 As shown, the control unit 80 starts the first decompression step S1 in the second chamber 12 at a time delayed by a predetermined delay time Δt from the start time of the first decompression step S1 in the first chamber 11. In addition, the control unit 80 starts the first decompression step S1 in the third chamber 13 at a time delayed by a predetermined delay time Δt from the start time of the first decompression step S1 in the second chamber 12. In addition, the control unit 80 starts the first decompression step S1 in the fourth chamber 14 at a time delayed by a predetermined delay time Δt from the start time of the first decompression step S1 in the third chamber 13.

[0175] The delay time Δt is set to a time longer than the time required for the second decompression step S2. If so, the second decompression step S2 will not be performed simultaneously in two or more chambers. That is, after the second decompression step S2 of the first chamber 11 is completed, the second decompression step S2 of the second chamber 12 is performed, after the second decompression step S2 of the second chamber 12 is completed, the second decompression step S2 of the third chamber 13 is performed, and after the second decompression step S2 of the third chamber 13 is completed, the second decompression step S2 of the fourth chamber 14 is performed. Therefore, the shared pump 55 can be switched between exhaust from the first chamber 11, exhaust from the second chamber 12, exhaust from the third chamber 13, and exhaust from the fourth chamber 14 and used in sequence. As a result, the same shared pump can be effectively used in the four chambers 11, 12, 13, and 14.

[0176] <4. Modifications>

[0177] As mentioned above, although one embodiment of the present invention has been described, the present invention is not limited to the above embodiment.

[0178] In the above embodiment, the decompression mechanism 20 has a plurality of shared pumps 55. However, the number of shared pumps 55 in the decompression mechanism 20 may be one. However, if a plurality of shared pumps 55 are provided as in the above embodiment, the suction force in the second decompression step S2 can be further increased.

[0179] In the above embodiment, the high vacuum pumps 61 to 64 are used only in the third decompression step S3. In the case where the high vacuum pump can only be driven at a certain low pressure, the high vacuum pump can also be driven between the first decompression step S1 and the second decompression step S2, with the valves before and after the high vacuum pump closed. For example, the first high vacuum pump 61 can be driven with the first opening and closing valve V31 and the first relay valve V41 closed. Similarly, the second high vacuum pump 62 can be driven with the second opening and closing valve V32 and the second relay valve V42 closed. Similarly, the third high vacuum pump 63 can be driven with the third opening and closing valve V33 and the third relay valve V43 closed. Similarly, the fourth high vacuum pump 64 can be driven with the fourth opening and closing valve V34 and the fourth relay valve V44 closed.

[0180] In addition, the reduced-pressure drying device 1 of the above-described embodiment includes four chambers 11 to 14. However, the number of chambers included in the reduced-pressure drying device 1 may be two, three, or five or more.

[0181] The reduced pressure drying device 1 of the above-described embodiment dries the coating layer on the substrate by only reducing pressure. However, the reduced pressure drying device 1 may also dry the coating layer on the substrate by reducing pressure and heating.

[0182] In addition, the reduced pressure drying apparatus 1 of the above-mentioned embodiment processes substrates for organic EL displays. However, the reduced pressure drying apparatus of the present invention can also process substrates for other precision electronic parts such as liquid crystal displays or semiconductor wafers.

[0183] Furthermore, the components in the above-described embodiment and modified examples may be combined as appropriate within a range where no contradiction occurs.

Claims

1. A vacuum drying device for drying a coating layer formed on an upper surface of a substrate by reducing pressure, the vacuum drying device comprising: The first chamber and the second chamber are capable of accommodating a substrate; as well as a decompression mechanism for exhausting gas from the first chamber and the second chamber, The decompression mechanism comprises: A first dedicated pump connected to only the first chamber of the first chamber and the second chamber via a first pipe; A second dedicated pump connected to only the second chamber of the first chamber and the second chamber via a second pipe; a first valve provided on the first pipe; a second valve provided on the second pipe; A common pump having a higher suction force than the first dedicated pump and the second dedicated pump; a first exhaust path connecting the first chamber to the common pump; a second exhaust path connecting the second chamber to the common pump; as well as A common switching unit switches between a closed state, a first open state, and a second open state, wherein the closed state is to close both the first exhaust path and the second exhaust path, the first open state is to close the second exhaust path and open the first exhaust path, and the second open state is to close the first exhaust path and open the second exhaust path. a) in a state where the first valve is opened and the shared switching unit is set to the first open state, exhausting gas from the first chamber by the first dedicated pump and the shared pump, and thereafter, b) exhausting gas from the second chamber by the second dedicated pump and the shared pump while the second valve is opened and the shared switch is in the second open state.

2. The reduced pressure drying device according to claim 1, wherein c) before step a), the first valve is opened and the shared switching unit is set to the closed state, and the gas is exhausted from the first chamber by the first dedicated pump. d) Before the above step b), the gas is exhausted from the second chamber by the second dedicated pump in a state where the second valve is opened and the shared switching unit is in the closed state.

3. The reduced pressure drying device according to claim 2, wherein The time for executing a) is shorter than the time for executing c), The time for executing b) is shorter than the time for executing d).

4. The reduced pressure drying device according to any one of claims 1 to 3, wherein The decompression mechanism includes a plurality of the shared pumps.

5. The reduced pressure drying device according to any one of claims 1 to 4, wherein The decompression mechanism also has: A first high vacuum pump connected to the first chamber; and A second high vacuum pump is connected to the second chamber.

6. The reduced pressure drying device according to claim 5, wherein e) after a), exhausting gas from the first chamber by the first high vacuum pump, f) After b), exhausting gas from the second chamber by using the second high vacuum pump.

7. A vacuum drying device for drying a coating layer formed on an upper surface of a substrate by reducing pressure, the vacuum drying device comprising: The first chamber and the second chamber are capable of accommodating a substrate; a decompression mechanism for exhausting gas from the first chamber and the second chamber, The decompression mechanism comprises: a first dedicated pump connected to the first chamber; a second dedicated pump connected to the second chamber; There are pumps in total; a first exhaust path connecting the first chamber to the common pump; a second exhaust path connecting the second chamber to the common pump; A common switching unit switches between a closed state, a first open state, and a second open state, wherein the closed state is to close both the first exhaust path and the second exhaust path, the first open state is to close the second exhaust path and open the first exhaust path, and the second open state is to close the first exhaust path and open the second exhaust path. a first high vacuum pump connected to the first chamber; a second high vacuum pump connected to the second chamber, The decompression mechanism also has: a first switching unit for switching between a state in which the first dedicated pump is connected to the first chamber and a state in which the first dedicated pump is connected to the downstream side of the first high vacuum pump; as well as The second switching unit switches between a state in which the second dedicated pump is connected to the second chamber and a state in which the second dedicated pump is connected to the downstream side of the second high vacuum pump.

8. A reduced pressure drying method, which dries a coating layer formed on the upper surface of a substrate by reducing pressure, the reduced pressure drying method comprising: a) exhausting gas from the first chamber by a first dedicated pump; b) exhausting gas from the second chamber by a second dedicated pump; c) after step a), exhausting gas from the first chamber by using the first dedicated pump and the shared pump; and d) after the steps b) and c), exhausting gas from the second chamber by the second dedicated pump and the shared pump, The common pump has a higher suction force than the first dedicated pump and the second dedicated pump.

9. The reduced pressure drying method according to claim 8, wherein In the step c), the gas is exhausted from the first chamber by the first dedicated pump and the plurality of shared pumps. In the step d), the gas is exhausted from the second chamber by the second dedicated pump and the plurality of shared pumps.

10. The reduced pressure drying method according to claim 8 or 9, further comprising: e) after step c), exhausting gas from the first chamber by a first high vacuum pump; and f) After step d), a step of exhausting gas from the second chamber by a second high vacuum pump.

11. A reduced pressure drying method, which dries a coating layer formed on an upper surface of a substrate by reducing pressure, the reduced pressure drying method comprising: a) exhausting gas from the first chamber by a first dedicated pump; b) exhausting gas from the second chamber by a second dedicated pump; c) after step a), exhausting gas from the first chamber by using the first dedicated pump and the shared pump; d) after the steps b) and c), exhausting gas from the second chamber by the second dedicated pump and the shared pump, e) after step c), exhausting gas from the first chamber by a first high vacuum pump; f) after step d), exhausting gas from the second chamber by a second high vacuum pump, In the step e), exhaust is performed by the first dedicated pump on the downstream side of the first high vacuum pump. In the step f), exhaust is performed by the second dedicated pump on the downstream side of the second high vacuum pump.

12. The reduced pressure drying method according to any one of claims 8 to 11, wherein The time for performing step c) is shorter than the time for performing step a), The time for performing the step d) is shorter than the time for performing the step b).

13. A vacuum drying device for drying a coating layer formed on an upper surface of a substrate by reducing pressure, the vacuum drying device comprising: a chamber capable of receiving a substrate; a pressure relief mechanism to exhaust gas from the chamber, The decompression mechanism comprises: a dedicated pump connected to the chamber; a high vacuum pump connected to the chamber and having a suction force stronger than that of the dedicated pump; a switching unit that switches between a state in which the dedicated pump is connected to the chamber and a state in which the dedicated pump is connected to the downstream side of the high vacuum pump; A common pump is connected to the connection between the chamber and the outside of the chamber; The reduced pressure drying device also includes: a control unit for controlling the switching unit, The control unit a) setting the switching unit to a state where the dedicated pump is connected to the chamber, so that the dedicated pump operates; b) after step a), setting the switching unit to a state where the dedicated pump is connected to the downstream side of the high vacuum pump, and operating the dedicated pump and the high vacuum pump, In the step a), the gas is exhausted from the chamber by using the common pump. In the step b), the gas is exhausted from the chamber without using the common pump.

14. The reduced pressure drying device according to claim 13, wherein The high vacuum pump is a turbomolecular pump.

15. A reduced pressure drying method, which dries a coating layer formed on an upper surface of a substrate by reducing pressure, the reduced pressure drying method comprising: a) exhausting gas from a chamber containing the substrate by a dedicated pump; b) after step a), exhausting gas from the chamber by using the dedicated pump and a high vacuum pump having a suction force stronger than that of the dedicated pump; In the step b), exhaust is performed by the dedicated pump on the downstream side of the high vacuum pump. In the step a), a common pump connected to the chamber and a connection point outside the chamber is used to exhaust gas from the chamber. In the step b), the gas is exhausted from the chamber without using the common pump.

16. The reduced pressure drying method according to claim 15, wherein The high vacuum pump is a turbomolecular pump.

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