CN117358548A

CN117358548A - Decompression drying device

Info

Publication number: CN117358548A
Application number: CN202310419640.5A
Authority: CN
Inventors: 北村翔也
Original assignee: Screen Holdings Co Ltd
Current assignee: Screen Holdings Co Ltd
Priority date: 2022-07-07
Filing date: 2023-04-19
Publication date: 2024-01-09
Also published as: JP7536832B2; TW202413869A; KR20240007064A; JP2024008110A

Abstract

The invention provides a technology for inhibiting uneven drying of a coating film. The decompression drying device (1) comprises a chamber (10), a plurality of support pins (22) and an exhaust part (30). The chamber (10) accommodates the substrate (9). A plurality of support pins (22) support the substrate (9) from below within the chamber (10). The exhaust unit (30) exhausts the gas in the chamber (10). The plurality of support pins (22) includes one or more first support pins (22 a) and one or more second support pins (22 b) that are thinner than the first support pins (22 a). At least one of the first support pins (22 a) supports a peripheral region in the substrate (9) from below. At least one of the second support pins (22 b) supports, from below, an area in which the coating film is formed in an inner area of the substrate (9) that is further inside than the peripheral area.

Description

Decompression drying device

Technical Field

The present disclosure relates to a decompression drying device.

Background

For example, a vacuum drying apparatus is known that performs vacuum drying of a coating film such as a photoresist applied to various substrates. For various substrates, various substrates such as glass substrates, ceramic substrates, semiconductor wafers, electronic element substrates, and printing plates for printing, which are used for forming various elements, are applicable. For various elements, for example, a semiconductor device, a display panel, a solar cell panel, a magnetic disk, an optical disk, or the like can be applied. As the display panel, for example, a liquid crystal display panel, an organic Electroluminescence (EL) display panel, a plasma display panel, a field emission display, or the like can be applied.

When the coating film is dried by using the reduced pressure drying apparatus, for example, in a state where a plurality of pins support a substrate in a chamber, the substrate is exhausted from the chamber by a vacuum pump through an exhaust port in the bottom of the chamber. Then, for example, when the vacuum degree reaches a predetermined value, the exhaust gas from the chamber is stopped, and the gas is supplied into the chamber to return the chamber to the atmospheric pressure. For the gas, for example, an inert gas such as nitrogen or air may be used.

In the reduced pressure drying apparatus, for example, in a coating film formed on the upper surface of a substrate, a drying unevenness (also referred to as a drying unevenness) may occur depending on the drying speed if the drying speed varies depending on the place. Uneven drying may cause, for example, thickness variation of the dried coating film.

For example, on the substrate, a temperature difference may occur between a portion supported by the plurality of pins and a portion around the portion due to contact of the plurality of pins. Thus, for example, the drying speed of the coating film may be different depending on the temperature difference caused by the plurality of pins. As a result, for example, uneven drying may occur in the coating film according to the arrangement of the plurality of pins. Here, for example, at the time of drying the coating film under reduced pressure, the temperature of the substrate is lowered by vaporization heat generated when the solvent or the like is vaporized from the coating film, but the temperature of the plurality of pins is hardly changed even when the heat capacity of the plurality of pins is large or when the plurality of pins are connected to a chamber or the like having a large heat capacity. Thus, for example, a temperature difference corresponding to the arrangement of the plurality of pins may be generated on the substrate.

Patent document 1 describes the following: the plurality of pins for supporting the substrate are hollow pins cooled by discharging a fluid in the internal space or hollow pins cooled by supplying a liquid such as cooling water into the internal space.

[ Prior Art literature ]

[ patent literature ]

[ patent document 1] Japanese patent publication No. 6579773

Disclosure of Invention

[ problem to be solved by the invention ]

However, in the decompression drying device of patent document 1, the device structure becomes complicated, and the device price becomes high. In addition, for example, in a structure in which cooling water is supplied to the hollow pin, it is also conceivable that the vacuum state in the chamber is adversely affected by leakage of the cooling water.

The present disclosure has been made in view of the above problems, and an object thereof is to provide a technique for suppressing uneven drying of a coating film.

[ means of solving the problems ]

A first embodiment is a reduced pressure drying apparatus that dries a coating film formed on an upper surface of a substrate, the reduced pressure drying apparatus including: a chamber for accommodating the substrate; a plurality of support pins for supporting the substrate from below in the chamber; and an exhaust unit configured to exhaust the gas in the chamber, wherein the plurality of support pins include one or more first support pins, at least one of the first support pins supporting a peripheral region of the substrate from below, and one or more second support pins thinner than the first support pins, and at least one of the second support pins supporting a region of the substrate on an inner side of the peripheral region, the region being formed with the coating film, from below.

According to the decompression drying device of the first embodiment, in the second embodiment, the inner side region of the substrate is supported only by the second support pins.

According to the decompression drying device of the first embodiment, in the third embodiment, at least another one of the first support pins supports an area other than the area where the coating film is formed in the inner area of the substrate.

The decompression drying device according to any one of the first to third embodiments, wherein in the fourth embodiment, a contact area of the first support pin with the substrate is larger than a contact area of the second support pin with the substrate.

The decompression drying device according to any one of the first to fourth embodiments, wherein in the fifth embodiment, the first support pins are spaced apart more widely than the second support pins.

The decompression drying device according to any one of the first to fifth embodiments, wherein in the sixth embodiment, the thermal conductivity of the second support pin is 0.12W/m·k or less.

The decompression drying device according to any one of the first to sixth embodiments, wherein in the seventh embodiment, the second support pin is formed of a porous resin.

[ Effect of the invention ]

With the first embodiment, at least one of the second support pins supports a region (hereinafter, referred to as a first region) in which a coating film is formed in an inner region of the substrate from below. Since the second support pin is thin, the generation amount of the upward air flow generated around the second support pin at the reduced pressure of the chamber is small. Therefore, even if the gas rises along the second support pins by the rising gas flow and is locally supplied to the lower surface of the first region of the substrate, it is difficult to cause deviation of the temperature distribution in the first region. Thus, uneven drying of the coating film on the first region can be suppressed.

With the second embodiment, even if the number, shape, and position of the regions where the coating films are formed are changed in the inner region, the regions can be supported by the second support pins.

With the third embodiment, the substrate can be more firmly supported.

With the fourth embodiment, the amount of offset in the horizontal direction of the substrate with respect to the first support pins can be suppressed. On the other hand, the amount of movement of heat between the second support pins and the substrate can be reduced, and uneven drying of the coating film can be further suppressed.

With the fifth embodiment, the number of first support pins can be reduced. Therefore, the manufacturing cost of the reduced pressure drying apparatus can be reduced. In addition, the man-hour of the replacement operation of the support pin can be reduced.

With the sixth embodiment and the seventh embodiment, the amount of movement of heat between the second support pin and the substrate can be reduced, and uneven drying of the coating film can be further suppressed.

Drawings

Fig. 1 is a view showing an example of a vertical section of a decompression drying device according to an embodiment.

Fig. 2 is a view showing an example of a cross section of a decompression drying device according to an embodiment.

Fig. 3 is a view showing an example of a vertical section of a decompression drying device according to an embodiment.

Fig. 4 is a perspective view showing an example of a substrate.

Fig. 5 is a view showing an example of a vertical cross section of a part of a substrate.

Fig. 6 is a front view showing an example of the appearance of the first support pin.

Fig. 7 is a front view showing an example of the appearance of the second support pin.

Fig. 8 is a diagram showing a first example of the relationship between the coating region of the substrate and the first and second support pins.

Fig. 9 is a diagram schematically showing an example of the air flow in the chamber under reduced pressure.

Fig. 10 is a block diagram conceptually showing functions that can be implemented in the control section.

Fig. 11 is a flowchart showing an example of the flow of the reduced pressure drying process according to the embodiment.

Fig. 12 is a diagram showing a second example of the relationship between the coating region of the substrate and the first and second support pins.

Fig. 13 is a diagram showing a third example of the relationship between the coating region of the substrate and the first and second support pins.

Description of symbols

1: decompression drying device

9: substrate board

9op: peripheral part (side)

10: chamber chamber

10s: interior space

11: bottom plate part

11h, 40h: through hole

12: side wall portion

13: top plate part

14: carrying in and carrying out port

15: gate part (sluice valve)

16: opening/closing driving part

16a, 16b, 16c, 16d: exhaust port

16f: air supply port

20: support part

21: supporting plate

22: supporting pin

22a: first support pin

22b: second supporting pin

23a: a first abutting part

23b: a second abutting part

25a: a first columnar portion

25b: second column part

26a: a first pedestal part

26b: a second pedestal part

27a: first external screw thread part

27b: second external screw thread part

30: exhaust part

31: exhaust pipe

31a, 31b, 31c, 31d: separate piping

31e: main piping

32: vacuum pump

40: bottom surface rectifying plate

41: diagonal line

50: side rectifying plate

60: air supply part

61: air supply piping

62: air supply source

70: pressure gauge

80: control unit

81: opening/closing control unit

82: lifting control part

83: switching control unit

84: exhaust gas control unit

85: pump control unit

86: air supply control part

90: coating film

100: lifting part

100a: body part

100b: moving part

801: processor and method for controlling the same

802: memory device

803: storage unit

803p: computer program (program)

804: input unit

805: output unit

806: communication unit

807: driver(s)

807m: storage medium

A1: area (formed area, coating area)

A2: area (non-coating area)

A3: area (covered area)

A4: area (exposed area)

B1: peripheral edge area

B2: inner region

B3: boundary of

F1: first surface

F2: a second surface

Ga. Gb: ascending air current

H1: lowered position

H2: lifting position

S1-S4: step (a)

Va, vb, vc, vd: individual valve

Ve: main valve

Vf: air supply valve

Detailed Description

An embodiment and various modifications of the present disclosure will be described below with reference to the drawings. In the drawings, portions having the same structure and function are denoted by the same reference numerals, and repetitive description thereof will be omitted. The drawings are merely schematically illustrated, and the dimensions, positional relationships, and the like of various structures in the drawings are not accurately illustrated. In the present specification, the downward direction is the gravitational direction, and the upward direction is the direction opposite to the gravitational direction.

< 1. Structure of decompression drying device >

Fig. 1 is a view schematically showing an example of a vertical cross section of a decompression drying device 1 according to an embodiment. Fig. 2 is a view schematically showing an example of a cross section of the reduced pressure drying apparatus 1 according to the embodiment. Fig. 3 is a view schematically showing an example of a vertical cross section of the decompression drying device 1 according to one embodiment. The vertical cross section of fig. 1 and the vertical cross section of fig. 3 show the structure of the decompression drying device 1 when viewed from directions different from each other by about 90 degrees. In fig. 3, for the sake of convenience, the structures related to the exhaust unit 30, the air supply unit 60, the pressure gauge 70, and the control unit 80, which will be described later, are omitted in order to avoid complicating the drawings. The decompression drying device 1 is a device for drying a coating film 90 (see fig. 5) formed on the upper surface of a substrate 9.

As the substrate 9, for example, a glass substrate, a semiconductor wafer, a ceramic substrate, or the like can be applied. The substrate 9 is, for example, a flat plate-shaped substrate having a first surface F1 (see fig. 4 and 5) as a first main surface and a second surface F2 (see fig. 5) as a second main surface opposite to the first surface F1. For example, in the decompression drying device 1, the first surface F1 of the substrate 9 is set as the upper surface of the substrate 9, and the second surface F2 of the substrate 9 is set as the lower surface of the substrate 9. Here, a specific example in which a rectangular glass substrate is applied to the substrate 9 will be described. The first surface F1 of the substrate 9 is partially coated with a coating film 90 by, for example, pre-coating a treatment liquid containing an organic material and a solvent. The application of the treatment liquid is performed by, for example, a slit coater or an inkjet device. As the treatment liquid, for example, a liquid (also referred to as Polyimide (PI) liquid) containing a Polyimide precursor and a solvent, a coating liquid such as a resist liquid, or the like can be used. For the polyimide precursor, for example, polyamide (Polyamide) acid (Polyamide acid) or the like can be used. As the solvent, NMP (N-Methyl-2-Pyrrolidone: N-Methyl-2-pyrrosidone) can be used, for example. In addition, for example, in the case where the reduced pressure drying apparatus 1 is applied to a process for manufacturing an organic EL display, an embodiment may be employed in which the coating film 90 is dried in the reduced pressure drying apparatus 1 to form a hole injection layer, a hole transport layer, or a light emitting layer of the organic EL display panel.

Fig. 4 is a perspective view showing an example of the substrate 9. Fig. 5 is a view showing an example of a vertical cross section of a part of the substrate 9. As shown in fig. 4, the substrate 9 has, for example, an embodiment of a rectangular shape having different lengths in a longitudinal and transverse direction in a plan view. A plurality of regions (also referred to as a formed region and a coated region) A1 for forming elements and the like are arranged on the substrate 9. In the example of fig. 4, four rectangular coating areas A1 are arranged in a matrix of two rows and two columns on the substrate 9 in a plan view. However, the shape, number, and arrangement of the application areas A1 are not limited to the examples described above. In the coating step before the reduced pressure drying step by the reduced pressure drying apparatus 1, the coating film 90 is formed in a desired pattern on the upper surface of each coating region A1 by a slit coater, an inkjet apparatus, or the like. For the desired mode, for example, a mode of a circuit may be applied. Here, for example, as shown in fig. 5, the first surface F1, which is the upper surface of each application region A1, has a region (also referred to as a covered region) A3 covered with the application film 90 and an exposed region (also referred to as an exposed region) A4 not covered with the application film 90. The area around the coating area A1 and between adjacent coating areas A1 in the substrate 9 is an area (also referred to as a non-coating area) A2 where the coating film 90 is not formed on the first surface F1 as the upper surface. The non-coating region A2 is also an exposed region (exposed region) A4 not covered with the coating film 90.

In the example of fig. 4, the peripheral region B1 and the inner region B2 in the substrate 9 are also shown. The peripheral edge region B1 of the substrate 9 is a frame-shaped region having a predetermined width inward from the outer peripheral portion (i.e., side surface) 9op of the substrate 9. The predetermined width is, for example, about 100mm or less. Here, the peripheral edge region B1 of the substrate 9 corresponds to a part of the non-coating region A2. That is, no element is formed on the upper surface of the peripheral edge region B1 of the substrate 9, and the coating film 90 is not formed here either. The inner region B2 of the substrate 9 is a region of the substrate 9 further inward than the peripheral region B1. The boundary B3 between the peripheral edge region B1 and the inner region B2 of the substrate 9 has, for example, a rectangular shape. Here, the inner region B2 of the substrate 9 includes a plurality of coating regions A1 and regions between the plurality of coating regions A1 (in fig. 4, cross-shaped non-coating regions A2). The inner region B2 has, for example, a rectangular shape in plan view.

Summary of structure of decompression drying device

First, the structure of the decompression drying device 1 will be summarized. As shown in fig. 1 and 2, the decompression drying device 1 includes, for example, a chamber 10, a support portion 20, and an exhaust portion 30. The chamber 10 is a portion for accommodating the substrate 9. The support portion 20 is provided in the chamber 10, and supports the substrate 9 in a horizontal posture. The horizontal posture referred to herein means a posture in which the thickness direction of the substrate 9 is along the up-down direction. The exhaust unit 30 exhausts the gas in the chamber 10 to the outside, and reduces the gas pressure in the chamber 10. Due to the drop in the air pressure, the solvent of the coating film 90 evaporates and the coating film 90 dries.

In the example of fig. 1 and 2, the decompression drying device 1 includes: lifting unit 100, air supply unit 60, control unit 80, bottom surface rectifying plate 40, side rectifying plate 50, and pressure gauge 70. The lifting unit 100 lifts and lowers the support unit 20. Thereby, the substrate 9 supported by the support portion 20 is also lifted and lowered in the chamber 10. The gas supply unit 60 supplies gas into the chamber 10. Thereby, the air pressure in the chamber 10 can be restored to the atmospheric pressure. The bottom rectifying plate 40 and the side rectifying plate 50 are disposed in the chamber 10, and adjust the air flow in the chamber 10. The pressure gauge 70 measures the air pressure in the chamber 10, and outputs an electric signal indicating the measurement result to the control unit 80. The control unit 80 controls various configurations of the decompression drying device 1. For example, the control unit 80 controls the exhaust unit 30 based on the air pressure measured by the pressure gauge 70, and adjusts the air pressure in the chamber 10 to the target air pressure.

Next, a detailed example of each structure of the decompression drying device 1 will be described.

Chamber 10

The chamber 10 is a portion for accommodating the substrate 9. As the chamber 10, a pressure-resistant container having an inner space 10s for accommodating the substrate 9 can be applied. The chamber 10 is fixed to a device frame, not shown, for example. The chamber 10 is, for example, in the shape of a flat rectangular parallelepiped. The chamber 10 has, for example, a substantially square bottom plate portion 11, four side wall portions 12, and a substantially square top plate portion 13. The four side wall portions 12 connect, for example, four end edges of the bottom plate portion 11 with four end edges of the top plate portion 13 in the up-down direction. For example, one side wall 12 of the four side wall 12 is provided with a carry-in/carry-out port 14 and a gate portion (also referred to as a gate valve) 15 for opening/closing the carry-in/carry-out port 14. The shutter portion 15 is coupled or connected to, for example, an opening/closing drive portion 16. In fig. 3, the opening/closing drive section 16 is conceptually shown in order to avoid complicating the drawing. For the opening/closing drive unit 16, a drive mechanism such as an air cylinder may be used. Here, for example, the shutter portion 15 is movable between a position (also referred to as a closed position) where the carry-in/out port 14 is closed and a position (also referred to as an open position) where the carry-in/out port 14 is opened by the operation of the opening/closing drive portion 16.

Here, for example, the internal space 10s of the chamber 10 is sealed in a state where the shutter portion 15 is located at the closed position. For example, in a state where the shutter portion 15 is located at the open position, the substrate 9 can be carried into the internal space 10s of the chamber 10 and the substrate 9 can be carried out from the internal space 10s of the chamber 10 through the carry-in/out port 14.

Support portion 20

The support 20 is a portion for supporting the substrate 9 from below in the chamber 10. For example, 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. The plurality of support plates 21 are portions that become bases of the support portions 20. The substrate 9 is disposed, for example, above the plurality of support plates 21, and the upper ends 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.

The plurality of support pins 22 include, for example, one or more first support pins 22a and one or more second support pins 22b. In other words, the support portion 20 includes a first support pin 22a and a second support pin 22b that support the substrate 9 from below. As shown in fig. 3, the first support pin 22a and the second support pin 22b have a bar-like shape long in the up-down direction, and the first support pin 22a is thicker than the second support pin 22b.

Fig. 6 is a front view showing an example of the appearance of the first support pin 22a, and fig. 7 is a front view showing an example of the appearance of the second support pin 22 b.

In the example of fig. 6, the first support pin 22a is provided upright on the upper surface of the first pedestal portion 26 a. That is, the first support pins 22a extend upward from the upper surface of the first pedestal portion 26 a. The first pedestal portion 26a is formed wider than the first support pin 22 a. In the example of fig. 6, a first male screw portion 27a is provided on the lower surface of the first pedestal portion 26 a. The first male screw portion 27a has a columnar shape extending downward from the lower surface of the first pedestal portion 26a, and screw threads are formed on the side surface thereof. The first support pin 22a is mounted on the upper surface of the support plate 21 by the screw action of the first male screw portion 27a. That is, the first external screw portion 27a is coupled to an internal screw portion (not shown) formed on the upper surface of the support plate 21 by screw action, whereby the first support pin 22a is mounted on the upper surface of the support plate 21.

The pin structure including the first support pin 22a, the first mount portion 26a, and the first male screw portion 27a may be integrally formed of the same material, or may be formed by combining a plurality of members. Further, if the entire pin structure is understood as the first support pin 22a, a portion above the upper surface of the first pedestal portion 26a may be understood as the first pin body portion.

In the example of fig. 6, the first support pin 22a includes a first contact portion 23a and a first columnar portion 25a. The first columnar portion 25a has a columnar shape extending in the up-down direction, and is erected on the upper surface of the first pedestal portion 26 a. That is, the first columnar portion 25a extends upward from the upper surface of the first pedestal portion 26 a. The first columnar portion 25a has a cylindrical shape, for example. In this case, the first columnar portion 25a has a circular shape in a horizontal cross section orthogonal to the vertical direction. For example, the first columnar portion 25a extends in the up-down direction with an equal width. The width (diameter in this case) of the first columnar portion 25a is set to, for example, 1mm or more, and as a specific example, about 3 mm.

The first contact portion 23a is provided on the upper end surface of the first columnar portion 25a. The first contact portion 23a has, for example, a cone-like shape. As a specific example, the first contact portion 23a may have a conical shape. Alternatively, the first contact portion 23a may have a hemispherical or semi-elliptical shape. In this case, the first contact portion 23a is also circular in shape in horizontal cross section. The width (here, the diameter) of the first contact portion 23a also decreases as it goes upward. The width (diameter in this case) of the lower end of the first contact portion 23a is equal to the width (diameter in this case) of the first columnar portion 25a, and is set to 1mm or more, for example, about 3mm as a more specific example. The upper end (i.e., the apex) of the first contact portion 23a contacts the second surface F2 of the substrate 9.

As described above, in the example of fig. 6, the first support pin 22a has a bar-like shape in which the width (here, the diameter) thereof decreases monotonously and non-increasingly as it goes upward. In the example of fig. 6, the width of the first support pin 22a is constant in the first columnar portion 25a independently of the vertical direction, and monotonically decreases in the first contact portion 23a with the upward direction.

As a material of the first support pin 22a, for example, a resin material such as polyetheretherketone (polyether ether ketone, PEEK) or Polyimide (PI) is applicable. For example, by appropriately adjusting the friction force of the resin material, the first support pins 22a can support the substrate 9 from below by the friction force between the upper ends of the first support pins 22a and the second surface F2 of the substrate 9 in such a manner that the substrate 9 is not shifted in the horizontal direction. The first support pin 22a is, for example, a solid material.

Next, an example of the lengths of the first contact portion 23a and the first columnar portion 25a in the up-down direction will be described. In the example of fig. 6, the length of the first abutting portion 23a is very short compared to the length of the first columnar portion 25 a. That is, the first columnar portion 25a is longest. In other words, the first columnar portion 25a has the largest proportion to the entire first support pin 22a in the up-down direction. Therefore, the thickness of the first support pin 22a can be represented by the thickness of the first columnar portion 25 a. That is, the width (here, the diameter) of the first columnar portion 25a mainly indicates the thickness of the first support pin 22 a.

In the example of fig. 7, the second support pin 22b is provided upright on the upper surface of the second pedestal portion 26 b. That is, the second support pins 22b extend upward from the upper surface of the second pedestal portion 26 b. The second pedestal portion 26b is formed wider than the second support pin 22 b. In the example of fig. 7, a second male screw portion 27b is provided on the lower surface of the second pedestal portion 26 b. The second male screw portion 27b has a columnar shape extending downward from the lower surface of the second pedestal portion 26b, and screw threads are formed on the side surfaces thereof. The second support pin 22b is mounted to the support plate 21 by the screw action of the second external screw thread portion 27b. The pin structure including the second support pin 22b, the second pedestal portion 26b, and the second externally threaded portion 27b may be integrally formed of the same material, or may be formed by combining a plurality of members. Further, if the entire pin structure is understood as the second support pin 22b, a portion above the upper surface of the second pedestal portion 26b may be understood as the second pin body portion.

In the example of fig. 7, the second support pin 22b includes a second abutment portion 23b and a second cylindrical portion 25b. The second columnar portion 25b has a columnar shape extending in the up-down direction, and is erected on the upper surface of the second pedestal portion 26 b. That is, the second cylindrical portion 25b extends upward from the upper surface of the second pedestal portion 26 b. The second cylindrical portion 25b has a cylindrical shape, for example. In this case, the horizontal cross section of the second columnar portion 25b is circular in shape. The second columnar portion 25b extends in the up-down direction with an equal width, for example. The width (diameter in this case) of the second columnar portion 25b is set to, for example, 0.6mm or more, and more specifically, about 1 mm.

The second abutting portion 23b is provided on the upper end surface of the second cylindrical portion 25 b. The second contact portion 23b has, for example, a cone-like shape. As a specific example, the second contact portion 23b may have a conical shape. Alternatively, the second contact portion 23b has a hemispherical or semi-elliptical shape. In this case, the second contact portion 23b is also circular in shape in horizontal cross section. The width (here, the diameter) of the second contact portion 23b also decreases as it goes upward. The width (diameter in this case) of the lower end of the second contact portion 23b is, for example, equal to the width (diameter in this case) of the second columnar portion 25b, and is, for example, set to 0.6mm or more, and is, for example, set to about 1mm as a more specific example. The upper end (i.e., the apex) of the second contact portion 23b contacts the second surface F2 of the substrate 9.

As described above, in the example of fig. 7, the second support pin 22b has a bar-like shape in which the width (here, the diameter) thereof decreases monotonously and non-increasingly as it goes upward. In the example of fig. 7, the width of the second support pin 22b is constant in the second columnar portion 25b independently of the vertical direction, and monotonically decreases in the second contact portion 23b with the upward direction.

As the material of the second support pins 22b, for example, a resin material such as polyether ether ketone or polyimide can be applied in the same manner as the first support pins 22 a. The second support pin 22b is, for example, a solid material.

Next, the lengths of the second contact portion 23b and the second columnar portion 25b in the up-down direction will be described. In the example of fig. 7, the length of the second abutment portion 23b is very short compared to the length of the second cylindrical portion 25 b. That is, the second columnar portion 25b has the largest proportion to the entire second support pin 22b in the up-down direction. Therefore, the thickness of the second support pin 22b can be represented by the thickness of the second columnar portion 25 b. That is, the width (here, the diameter) of the second columnar portion 25b mainly indicates the thickness of the second support pin 22 b.

As can be understood from a comparison of fig. 6 and 7, the first support pin 22a is thicker than the second support pin 22 b. Here, the first columnar portion 25a is thicker than the second columnar portion 25 b. The difference between the width (diameter here) of the first columnar portion 25a and the width (diameter here) of the second columnar portion 25b may be, for example, 0.5mm or more, or 1mm or more, or 2mm or more.

Here, a comparison of the width of the first support pin 22a and the width of the second support pin 22b in the same horizontal section is further examined. As shown in fig. 6 and 7, the width of the first support pin 22a in any horizontal cross section may be equal to or greater than the width of the second support pin 22b in the entire vertical direction of the first support pin 22a and the second support pin 22 b. For example, the upper portion of the first contact portion 23a of the first support pin 22a and the second contact portion 23b of the second support pin 22b may have the same shape. According to the shape, the width of the upper portion of the first abutting portion 23a and the width of the second abutting portion 23b in the horizontal cross section are equal to each other. On the other hand, the width of the lower portion of the first contact portion 23a becomes larger as it goes downward, so that the width of the lower portion of the first contact portion 23a of the first support pin 22a is larger than the width of the second columnar portion 25b of the second support pin 22b in the same horizontal cross section. The width of the first columnar portion 25a is also larger than the width of the second columnar portion 25b in the same horizontal cross section. According to this shape, the first support pin 22a and the second support pin 22b are the same in thickness or thicker than the second support pin 22b in an arbitrary horizontal cross section.

The comparison of the thicknesses of the first support pin 22a and the second support pin 22b may be defined by, for example, comparing, in the same horizontal cross section, a first full-circle length corresponding to the contour of the side surface of the first support pin 22a with a second full-circle length corresponding to the contour of the side surface of the second support pin 22 b. In the above example, the first support pin 22a and the second support pin 22b have circular horizontal cross-sections, and thus the entire circumferential length corresponds to the circumferential length.

Here, when the horizontal cross section is moved in the vertical direction, the vertical range in which the first full circumferential length is longer than the second full circumferential length may be 5 or more with respect to the vertical length of the first support pin 22a and the second support pin 22 b. In this case, it can be said that the first support pin 22a is thicker than the second support pin 22 b. The ratio may be, for example, 6 or more, 7 or more, or 8 or more.

Fig. 8 is a diagram showing a first example of the positional relationship between the substrate 9 and the first support pins 22a and the second support pins 22 b. In fig. 8, in the second surface F2 as the lower surface of the substrate 9, the positions supported by the first support pins 22a are indicated by white circles, and the positions supported by the second support pins 22b are indicated by black circles. In fig. 8, the outer edge of the coating region A1 on the substrate 9 and the boundaries B3 of the peripheral region B1 and the inner region B2 on the substrate 9 are respectively depicted by two-dot chain lines.

As shown in fig. 8, a plurality of first support pins 22a support the peripheral region B1 of the substrate 9. That is, the upper ends of these first support pins 22a are in contact with the lower surface of the peripheral edge region B1 of the substrate 9. Since the peripheral edge region B1 of the substrate 9 has a rectangular frame-like shape in plan view, the first support pins 22a are also arranged along the rectangular frame over the entire circumference. In the example of fig. 8, the coating film 90 is not formed on the upper surface of the peripheral edge region B1 of the substrate 9. That is, the peripheral region B1 corresponds to the non-coating region A2. In the example of fig. 8, the remaining first support pins 22a are located in regions other than the coating region A1 in the inner region B2 of the substrate 9. That is, the remaining first support pins 22a support the inner region B2 of the substrate 9, but support the non-coating region A2 in the inner region B2. In other words, the upper ends of the remaining first support pins 22a are in contact with the lower surface of the non-coating region A2 in the inner region B2 of the substrate 9.

On the other hand, the plurality of second support pins 22B support the coating region A1 in the inner region B2 of the substrate 9. That is, the upper ends of the plurality of second support pins 22b are in contact with the lower surface of the coating region A1 of the substrate 9. When the coating film 90 having a pattern is formed in the coating region A1, the plurality of second support pins 22b can support the coating region A3 in the coating region A1, and the remaining second support pins 22b can support the exposed region A4 in the coating region A1. When the coating film 90 is formed on the entire coating region A1, the entire coating region A1 corresponds to the coating region A3, and therefore all the second support pins 22b support the coating region A3.

As described above, in the example of fig. 8, all the second support pins 22b are in contact with the lower surface of the coating region A1 in the substrate 9, and all the first support pins 22a are in contact with the lower surface of the non-coating region A2 in the substrate 9.

Fig. 9 is a diagram schematically showing an example of the air flow in the chamber 10 under reduced pressure. When the gas in the chamber 10 is discharged from the gas discharge portion 30, the temperature of the gas in the chamber 10 drops sharply due to adiabatic expansion. The temperature of the gas in the chamber 10 can be reduced to, for example, about minus (-) 20 degrees celsius. On the other hand, the temperature of the object (solid) in the chamber 10 also decreases. For example, the temperature of the substrate 9 is lowered by absorption of vaporization heat accompanying evaporation of the solvent of the coating film 90 and heat exchange between the substrate 9 and the surrounding gas. In addition, for example, the temperature of the support pins 22 decreases due to heat exchange of the support pins 22 with the surrounding gas. However, the temperature drop of these objects is not so large as compared with the temperature drop of the gas generated by adiabatic expansion, and for example, the temperature drop amount of the support pins 22 is about several degrees (for example, about 2 degrees or less). Therefore, the temperature of the support pins 22 is, for example, about 23 ℃.

By heat exchange between the support pins 22 and the gas, the gas is heated around the support pins 22. Accordingly, an updraft Ga and an updraft Gb are generated around the first support pin 22a and the second support pin 22b, respectively. The gas rises along the first support pins 22a by the rising gas flow Ga, and the gas rises along the second support pins 22b by the rising gas flow Gb. Therefore, the gas can be locally supplied to the second surface F2 of the substrate 9 by the upward gas flow Ga and the upward gas flow Gb. Therefore, the periphery of the contact portion with the support pin 22 (hereinafter, referred to as a pin vicinity area) in the substrate 9 is more susceptible to the upward airflow Ga and the upward airflow Gb than the region distant from the pin vicinity area (hereinafter, referred to as a pin separation area). As a result, the difference between the temperature of the pin vicinity region and the temperature of the pin separation region in the substrate 9 becomes large, and the temperature distribution of the substrate 9 may become uneven.

In the present embodiment, the second support pin 22b is thinner than the first support pin 22 a. That is, the second full circumferential length of the second support pin 22b in the horizontal section is shorter than the first full circumferential length of the first support pin 22a in the horizontal section. In other words, the surface area of the side surface of the second support pin 22b is smaller than the surface area of the side surface of the first support pin 22 a. Therefore, the gas around the first support pins 22a exchanges heat with the first support pins 22a with a larger surface area, and the gas around the second support pins 22b exchanges heat with the second support pins 22b with a smaller surface area. Thus, the rising air flow Ga is generated in a wider range (i.e., around the thick first support pins 22 a), and the rising air flow Gb is generated in a narrower range (i.e., around the thin second support pins 22 b). Therefore, the generation amount (for example, the volume flow rate) of the updraft Gb is smaller than that of the updraft Ga. In fig. 9, the generation amounts of the upward flow Ga and the upward flow Gb are schematically shown by the thickness of the arrow lines.

The second support pin 22b abuts against the lower surface of the coating region A1 of the substrate 9. Therefore, the gas can be locally supplied to the lower surface of the coating region A1 by the upward gas flow Gb around the second support pins 22 b. However, the generation amount of the updraft Gb is small, and therefore uniformity of the temperature in the coating area A1 is not so hindered. Therefore, compared with a structure in which the first support pins 22a are employed as the support pins 22 that abut against the lower surface of the coating region A1, the uniformity of the temperature distribution in the coating region A1 of the substrate 9 can be improved. As a result, the coating film 90 can be dried more uniformly. In other words, the occurrence of drying unevenness in the coating film 90 formed on the upper surface of the substrate 9 can be suppressed.

On the other hand, the first support pins 22a are in contact with the lower surface of the non-coating region A2 of the substrate 9. Therefore, the gas can be locally supplied to the lower surface of the non-coating region A2 of the substrate 9 by the upward gas flow Ga. The generation amount of the rising gas flow Ga is relatively large, and therefore the temperature distribution in the non-coating region A2 may become uneven as compared with the coating region A1. However, in the example, the coating film 90 is not formed in the non-coating region A2, and thus, poor drying of the coating film 90 is hardly caused.

Further, the first support pin 22a is thicker than the second support pin 22b, and thus has higher rigidity than that of the second support pin 22 b. Therefore, the first support pins 22a can more firmly support the peripheral edge region B1 of the substrate 9. For comparison, a structure (hereinafter referred to as a comparison structure) in which the second support pins 22b are thin is adopted for all the support pins 22 is examined. In the comparative structure, the substrate 9 can be displaced in the horizontal direction when an external force is applied to the substrate 9 in the horizontal direction. The reason for this is that: the thinner the support pin 22 is, the weaker the support pin 22 is against external force in the horizontal direction. For example, the support pin 22 can be deflected with the pedestal portion as a fixed end. When the substrate 9 is carried in and out or when the pressure in the chamber 10 is reduced, an external force having a component in the horizontal direction can be applied to the substrate 9, and therefore the substrate 9 can be displaced in the horizontal direction. Such displacement of the substrate 9 in the horizontal direction is not preferable.

In contrast, in the present embodiment, the first support pins 22a of the peripheral region B1 of the support substrate 9 are thicker than the second support pins 22B of the coating region A1 in the inner region B2 of the support substrate 9. Therefore, the first support pins 22a can support the peripheral edge region B1 of the substrate 9 more rigidly. Therefore, even if an external force having a horizontal component is applied to the substrate 9, the thick first support pins 22a can effectively suppress displacement of the substrate 9 in the horizontal direction. Further, if the first support pins 22a are arranged over the entire circumference along the circumferential direction of the peripheral edge region B1 of the substrate 9, the peripheral edge region B1 of the substrate 9 can be supported more firmly, and displacement of the substrate 9 in the horizontal direction can be suppressed more effectively.

Exhaust part 30

Referring to fig. 1, the exhaust portion 30 is a portion for exhausting the gas in the chamber 10. As shown in fig. 1 and 2, four exhaust ports 16a, 16b, 16c, and 16d are provided in the bottom plate portion 11 of the chamber 10 at portions facing the substrate 9 in the vertical direction, for example. The exhaust unit 30 includes, for example, an exhaust pipe 31, four individual valves Va, vb, vc, vd, a main valve Ve, and a vacuum pump 32. The exhaust pipe 31 includes, for example, four separate pipes 31a, 31b, 31c, 31d and one main pipe 31e. For example, one end of the separate pipe 31a is connected to the exhaust port 16a, one end of the separate pipe 31b is connected to the exhaust port 16b, one end of the separate pipe 31c is connected to the exhaust port 16c, and one end of the separate pipe 31d is connected to the exhaust port 16d. For example, the other ends of the four individual pipes 31a, 31b, 31c, 31d are joined together and 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 individual valve Va is provided on the path of the individual pipe 31a, the individual valve Vb is provided on the path of the individual pipe 31b, the individual valve Vc is provided on the path of the individual pipe 31c, and the individual valve Vd is provided on the path of the individual pipe 31 d. For example, the main valve Ve is provided on the path of the main pipe 31e.

Here, for example, when the vacuum pump 32 is operated by opening at least one of the four individual valves Va, vb, vc, vd and one main valve Ve in a state where the carry-in/carry-out port 14 is closed by the shutter portion 15, the gas in the chamber 10 is discharged to the outside of the chamber 10 through the exhaust pipe 31. Thus, for example, the air pressure in the internal space 10s of the chamber 10 can be reduced. The four individual valves Va, vb, vc, vd are, for example, valves for individually adjusting the amounts of exhaust gas from the four exhaust ports 16a, 16b, 16c, 16 d. For each of the four individual valves Va, vb, vc, vd, for example, a valve (also referred to as an on-off valve) that switches between an open state and a closed state based on a command from the control unit 80 can be applied. The main valve Ve is, for example, a valve for adjusting the total amount of exhaust gas from the four exhaust ports 16a, 16b, 16c, 16 d. For the main valve Ve, for example, a valve (also referred to as an opening control valve) capable of adjusting the opening based on a command from the control unit 80 is applicable.

Lifting part 100

The lifting portion 100 is a portion for lifting and lowering the support portion 20 in the chamber 10. In other words, for example, the lifting unit 100 has a mechanism (also referred to as a lifting mechanism) that can lift the support unit 20. In fig. 1, in order to avoid complicating the drawing, a lifting part 100 is conceptually shown. For example, a driving device such as a direct-acting motor or an air cylinder may be applied to the lifting unit 100. As shown in fig. 3, the lifting unit 100 includes a main body 100a and a moving unit 100b, for example. The main body 100a is fixed to a device frame, not shown, outside the chamber 10, for example. The moving portion 100b is movable in the up-down direction with respect to the main body portion 100a, for example. For example, a rod-shaped member or the like may be applied to the moving portion 100b. The moving portion 100b is, for example, in a state of being inserted into the through hole 11h of the bottom plate portion 11 of the chamber 10. Further, for example, a support portion 20 is fixed to an upper end portion of the moving portion 100b. Here, for example, if a bellows or the like is provided between the lower surface of the bottom plate portion 11 and the moving portion 100b, a gap between the bottom plate portion 11 and the moving portion 100b can be sealed. For example, in the case where the support portion 20 includes a plurality of support plates 21, the moving portion 100b includes a rod-shaped portion (also referred to as a rod-shaped portion) fixed to the support plate 21 and inserted into the through hole 11h of the bottom plate portion 11 for each support plate 21, a portion (also referred to as a connecting portion) connecting the plurality of rod-shaped portions, and a portion (also referred to as a sliding portion) connected to the connecting portion and slidably supported by the main body portion 100 a.

Here, for example, when the lifting/lowering unit 100 is operated, the supporting unit 20 is lifted up and down between a lowered position H1 (a position indicated by a dashed-dotted line in fig. 1 and 3) and a raised position H2 (a position indicated by a dashed-two dotted line in fig. 1 and 3) higher than the lowered position H1. At this time, for example, the plurality of support plates 21 can be lifted and lowered integrally.

Bottom surface rectifying plate 40

The bottom surface rectifying plate 40 is a plate for restricting the flow of gas in the internal space 10s when the inside of the chamber 10 is depressurized by the exhaust portion 30. For example, the bottom surface rectifying plate 40 is arranged to be located between the substrate 9 supported by the support portion 20 and the bottom plate portion 11 of the chamber 10. The bottom surface rectifying plate 40 is fixed to the bottom plate 11 of the chamber 10 via a plurality of struts, not shown, for example. As shown in fig. 2, for example, the bottom surface rectifying plate 40 has a square shape in a plan view. For example, the length of each side of the bottom surface rectifying plate 40 in plan view is longer than any one of the long side and the short side of the rectangular substrate 9. Therefore, for example, the bottom surface rectifying plate 40 is larger than the substrate 9 in a plan view, regardless of the orientation of the substrate 9 disposed on the support portion 20. The bottom surface rectifying plate 40 has, for example, a through hole 40h through which the moving part 100b of the lifting part 100 is inserted. In the through hole 40h, the bottom surface rectifying plate 40 is located at a very small distance from the moving portion 100 b.

Side rectifying plate 50

The side rectifying plate 50 is a plate for restricting the flow of gas in the internal space 10s when the inside of the chamber 10 is depressurized by the exhaust unit 30 together with the bottom rectifying plate 40. For example, the side rectifying plate 50 is disposed between the substrate 9 supported by the support portion 20 disposed at the lowered position H1 and the side wall portion 12 of the chamber 10. Here, for example, four side rectifying plates 50 are arranged so as to surround the periphery of the substrate 9 supported by the support portion 20. For example, the four side rectifying plates 50 are formed as a whole as a rectangular tubular rectifying plate surrounding the substrate 9. For example, the bottom rectifying plate 40 and the four side rectifying plates 50 are integrally formed with a bottom cylindrical box-shaped rectifying plate.

Here, for example, when the interior of the chamber 10 is depressurized by the exhaust unit 30, the gas in the internal space 10s of the chamber 10 is discharged to the outside of the chamber 10 through the space between the side rectifying plate 50 and the side wall 12, the space between the bottom rectifying plate 40 and the bottom plate 11, and the exhaust ports 16a, 16b, 16c, and 16d in the order described above. In this way, for example, by the gas flowing in a space away from the substrate 9, it is difficult to form a gas flow in the vicinity of the substrate 9. In addition, it is difficult to generate a concentrated air flow at the peripheral edge of the substrate 9. This can suppress, for example, the occurrence of uneven drying of the coating film 90 formed on the upper surface of the substrate 9.

Here, for example, as shown in fig. 2, four exhaust ports 16a, 16b, 16c, 16d are each located on a diagonal line 41 of a square bottom surface rectifying plate 40 in a plan view. In this case, for example, the air flow symmetrical to the center (the intersection of the two diagonal lines 41) of the bottom surface rectifying plate 40 can be formed by the respective air outlet 16a, 16b, 16c, and 16 d. Thereby, for example, in the inner space 10s of the chamber 10, a more uniform air flow can be formed.

Air supply portion 60

The gas supply unit 60 is a unit that performs an operation of supplying gas into the chamber 10 (also referred to as gas supply). As shown in fig. 1, for example, an air supply port 16f is provided in the bottom plate portion 11 of the chamber 10. The air supply port 16f is located, for example, below the bottom surface rectifying plate 40. The air supply portion 60 includes an air supply pipe 61 connected to the air supply port 16f, an air supply valve Vf, and an air supply source 62. For example, one end of the air supply pipe 61 is connected to the air supply port 16f. For example, the other end of the air supply pipe 61 is connected to the air supply source 62. For example, the air supply valve Vf is provided in the path of the air supply pipe 61.

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

Pressure gauge 70

The pressure gauge 70 is a sensor that measures the air pressure of the internal space 10s of the chamber 10. As shown in fig. 1, for example, a pressure gauge 70 is mounted to a portion of the chamber 10. The pressure gauge 70 may measure, for example, the air pressure in the internal space 10s of the chamber 10, and output the measurement result to the control unit 80.

Control part 80

The control unit 80 is a means for controlling the operations of the respective units of the decompression drying device 1. For example, the control unit 80 may control the exhaust unit 30, the air supply unit 60, the lifting unit 100, and the like. The control unit 80 includes, for example, a computer having a processor 801 such as a central processing unit (Central Processing Unit, CPU), a memory 802 such as a random access memory (Random Access Memory, RAM), and a storage unit 803 such as a hard disk drive. The storage 803 stores, for example, a computer program (also referred to as a program) 803p and various data for executing a process (also referred to as a reduced pressure drying process) for drying the coating film 90 on the substrate 9 by reduced pressure in the reduced pressure drying apparatus 1. The storage 803 stores, for example, a program 803p, and functions as a non-transitory storage medium readable by a computer. The control unit 80 reads out the program 803p and data from the storage unit 803 to the memory 802, for example, and performs arithmetic processing according to the program 803p and data in the processor 801, thereby controlling the operations of the respective units of the decompression drying device 1. Thus, for example, the program 803p can execute the reduced pressure drying process by being executed by the processor 801 included in the control unit 80 in the reduced pressure drying apparatus 1.

The control unit 80 may be connected to, for example, an input unit 804, an output unit 805, a communication unit 806, and a driver 807. The input unit 804 is a part for inputting various signals to the control unit 80 in response to a user's operation or the like, for example. The input unit 804 may include, for example, an operation unit that inputs a signal corresponding to an operation by a user, a microphone that inputs a signal corresponding to a sound of the user, and various sensors that input a signal corresponding to a motion of the user. The output unit 805 is, for example, a unit that outputs various information in an embodiment that can be recognized by a user. The output unit 805 includes, for example, a display unit, a projector, and a speaker. The display unit may be a touch panel integrated with the input unit 804. The communication unit 806 is a part for transmitting and receiving various information to and from an external device such as a server through a wired or wireless communication means, for example. For example, the storage 803 may store a program 803p received from an external device via the communication unit 806. The drive 807 is a part of a removable storage medium 807m such as a magnetic disk or an optical disk, for example. The drive 807 exchanges data between the storage medium 807m and the control unit 80 in a state where the storage medium 807m is mounted, for example. For example, the storage medium 807m in which the program 803p is stored may be provided to the drive 807, and the program 803p may be read from the storage medium 807m and stored in the storage 803. Here, the storage medium 807m stores the program 803p, for example, and functions as a non-transitory storage medium readable by a computer.

Fig. 10 is a block diagram conceptually showing functions implemented in the control section 80. As shown in fig. 10, the control unit 80 is electrically connected to, for example, the opening/closing drive unit 16, the lifting unit 100, the four individual valves Va, vb, vc, vd, the main valve Ve, the vacuum pump 32, the air supply valve Vf, and the pressure gauge 70, respectively. The control unit 80 may control the operations of the respective units with reference to the measured values output from the pressure gauge 70, for example.

As conceptually shown in fig. 10, the control unit 80 has, for example, an opening/closing control unit 81, a lifting control unit 82, a switching control unit 83, an exhaust control unit 84, a pump control unit 85, and an air supply control unit 86 as functional configurations to be realized. For example, the opening/closing control unit 81 controls the operation of the opening/closing driving unit 16. For example, the elevation control unit 82 controls the operation of the elevation unit 100. For example, the switching control section 83 individually controls the open/closed states of the four individual valves Va, vb, vc, vd. For example, the exhaust gas control unit 84 controls the open/close state and the opening degree of the main valve Ve. For example, the pump control unit 85 controls the operation of the vacuum pump 32. For example, the air supply control unit 86 controls the open/close state of the air supply valve Vf. The functions of each unit of the control unit 80 are realized by, for example, the processor 801 performing arithmetic processing according to the program 803p and the like.

< 2 decompression drying treatment >)

Next, a vacuum drying process of the substrate 9 using the vacuum drying apparatus 1 will be described. Fig. 11 is a flowchart showing an example of the flow of the reduced pressure drying process according to the embodiment. The flow of the decompression drying process is realized by, for example, executing the program 803p in the processor 801 included in the control section 80. Here, for example, the processing of steps S1 to S4 of fig. 11 is performed in the order described.

When the reduced pressure drying process is performed using the reduced pressure drying apparatus 1, for example, first, the substrate 9 is carried into the chamber 10 (step S1). At this time, an undried coating film 90 is formed on the upper surface of the substrate 9. In step S1, for example, the gate unit 15 opens the carry-in/carry-out port 14 under the control of the control unit 80, and the substrate 9 is carried into the internal space 10S of the chamber 10 through the carry-in/carry-out port 14 of the chamber 10 while the substrate 9 is placed on a fork-shaped robot arm by a not-shown transfer robot. At this time, the support portion 20 is disposed at the descent position H1, for example. The transfer robot inserts, for example, a fork-like robot arm between the plurality of support plates 21 of the support unit 20, and simultaneously places the substrate 9 on the support unit 20, and thereafter withdraws the fork to the outside of the chamber 10. Then, the gate unit 15 closes the carry-in/carry-out port 14 under the control of the control unit 80. As described above, in step S1, the step of placing the substrate 9 on the plurality of support pins 22 disposed in the chamber 10 (also referred to as a placing step) is performed.

In the step S1, the substrate 9 is supported by the plurality of support pins 22. Specifically, the peripheral edge region B1 of the substrate 9 is supported by the first support pins 22a, and the coating region A1 in the inner region B2 of the substrate 9 is supported by the second support pins 22B. In addition, the non-coating region A2 in the inner region B2 of the substrate 9 is supported by the first support pins 22 a.

Next, the decompression drying device 1 discharges the gas in the chamber 10 (step S2). Specifically, the control unit 80 causes the exhaust unit 30 to exhaust the gas in the chamber 10, thereby depressurizing the chamber 10. In other words, in step S2, a step of depressurizing the chamber 10 (also referred to as an evacuation step) is performed. Through the exhaust process, the air pressure in the chamber 10 is reduced to the target air pressure.

In step S2, for example, the control unit 80 may appropriately raise and lower the support unit 20, may individually appropriately control the open/closed states of the individual valves Va, vb, vc, vd, and may appropriately control the opening degree of the main valve Ve. For example, the decompression drying device 1 may be configured to gradually discharge the gas in the chamber 10 in a state where the support portion 20 is moved to the raised position H2 at the initial stage of the discharging process (first process), and then, after the support portion 20 is moved to the lowered position H1, the gas in the chamber 10 may be rapidly discharged by the discharging portion 30 (second process). This can reduce the pressure in the chamber 10 while suppressing the generation of strong air flow around the substrate 9 in the chamber 10.

Thereafter, the gas discharge unit 30 discharges the gas in the chamber 10 so that the gas pressure in the chamber 10 is substantially constant at the target gas pressure (third process). When the air pressure reaches the target air pressure, the solvent of the coating film 90 boils and the drying of the coating film 90 proceeds at a higher speed. When the boiling of the coating film 90 is completed, the exhaust unit 30 may further decompress the inside of the chamber 10 (fourth process). This can more reliably dry the coating film 90.

In addition, the temperature of the gas in the chamber 10 drops sharply due to the discharge of the gas in the chamber 10, and the temperature of each object in the chamber 10 also drops to some extent. Accordingly, as described above, the updraft Ga and the updraft Gb are generated around the first support pin 22a and around the second support pin 22b in the chamber 10, respectively. However, since the generation amount of the rising gas flow Gb is smaller than that of the rising gas flow Ga, the variation in the temperature distribution of the coating region A1 of the substrate 9 due to the rising gas flow Gb is small. Therefore, the occurrence of drying unevenness due to the variation in the temperature distribution of the substrate 9 can be suppressed.

In the exhaust step, the control unit 80 may cause uneven drying of the coating film 90 by the air flow between the upper surface of the substrate 9 and the top plate 13. In order to suppress the occurrence of the drying unevenness, the open/close states of the four individual valves Va, vb, vc, vd may be sequentially switched in each of the first to third processes. For example, the switching control section 83 closes one of the four individual valves Va, vb, vc, vd and opens the other individual valve. The switching control unit 83 sequentially changes the closed single valve. Specifically, the first state in which one individual valve Va is closed and the other three individual valves Vb, vc, vd are opened, the second state in which one individual valve Vb is closed and the other three individual valves Va, vc, vd are opened, the third state in which one individual valve Vc is closed and the other three individual valves Va, vb, vd are opened, and the fourth state in which one individual valve Vd is closed and the other three individual valves Va, vb, vc are opened are sequentially switched. In this way, in the exhaust process, the direction of the air flow in the space formed between the upper surface of the substrate 9 and the top plate 13 changes according to the switching of the individual valves Va, vb, vc, vd. Thus, the coating film 90 on the upper surface of the substrate 9 can be dried more uniformly. On the other hand, in the fourth process, since evaporation of the solvent is not active, the four individual valves Va, vb, vc, vd can also be opened entirely.

Next, the control unit 80 opens the air supply valve Vf. Thereby, the gas is supplied from the gas supply source 62 to the internal space 10S of the chamber 10 through the gas supply pipe 61 and the gas supply port 16f (step S3). Thereby, the air pressure in the chamber 10 rises again to the atmospheric pressure.

Then, for example, the substrate 9 is finally carried out of the chamber 10 (step S4). In step S4, for example, first, the gate portion 15 opens the carry-in/carry-out port 14 under the control of the control portion 80, and the carry-in/carry-out port 14 of the chamber 10 is passed through by a carry-in robot, not shown, to carry out the dried substrate 9 placed on the support portion 20 to the outside of the chamber 10. This can end the reduced pressure drying process for one substrate 9.

In this way, the method of drying the coating film 90 formed on the first surface F1, which is the upper surface of the substrate 9, using the reduced pressure drying apparatus 1 (also referred to as a reduced pressure drying method) includes, for example, a mounting step and an exhausting step.

As described above, in the decompression drying device 1 according to one embodiment, the substrate 9 is placed on the first support pins 22a and the second support pins 22b in step S1. The first support pins 22a are thicker than the second support pins 22B, and in the example of fig. 8, a plurality of the first support pins 22a support the peripheral region B1 of the substrate 9, and the second support pins 22B support the coating region A1 in the inner region B2 of the substrate 9. Since the thick first support pins 22a support the peripheral edge region B1 of the substrate 9, even if an external force of a horizontal component is applied to the substrate 9 due to an air flow in the exhaust process, for example, displacement of the substrate 9 in the horizontal direction can be suppressed more reliably.

On the other hand, the generation amount of the upward air flow Ga around the first support pin 22a generated in the exhaust process is relatively large. Therefore, the uniformity of the temperature distribution in the peripheral edge area B1 can be reduced. However, the coating film 90 is not formed in the peripheral region B1, and thus the generation of drying unevenness is hardly caused.

The second support pins 22b supporting the coating region A1 of the substrate 9 are thin, so that the generation amount of the updraft Gb around the second support pins 22b generated in the exhaust process can be reduced. Therefore, the gas supply of the ascending gas flow Gb to the lower surface of the coating region A1 of the substrate 9 can be suppressed. Therefore, the amount of deviation in the temperature distribution in the coating region A1 can be reduced, and the occurrence of uneven drying of the coating film 90 can be suppressed.

As described above, according to the decompression drying device 1 of the embodiment, both the suppression of the displacement of the substrate 9 in the horizontal direction and the suppression of the deviation of the temperature distribution in the application area A1 can be achieved.

In the example of fig. 8, the non-coating region A2 in the inner region B2 of the substrate 9 is supported by the thick first support pins 22 a. Accordingly, the substrate 9 can be more firmly supported.

Number of support pins

As described above, displacement in the horizontal direction of the substrate 9 can be suppressed by the thick first support pins 22 a. Therefore, the number of the second support pins 22b can be determined by considering only the strength in the buckling direction of the second support pins 22 b. For example, the buckling load Pcr of the support pin 22 can be expressed by the following equation.

[ number 1]

Here, E denotes young's modulus, imin denotes the minimum value of the section secondary moment, and L denotes the length of the support pin 22.

For example, in the case of a diameter of 0.5mm, a Young's modulus of 4300MPa, and a length of the support pin 22 of 30mm, the buckling load Pcr is about 0.29N. The weight of the substrate 9 applied to each of the second support pins 22b is not more than the buckling load Pcr, and therefore, the substrate 9 has a specific gravity of 3g/cm and a thickness of 0.5mm for support ³ A second support pin 22b is required every 130 mm.

Arrangement of support pins

In the example of fig. 8, the first support pins 22a are in contact with the lower surface of the non-coating region A2 of the substrate 9, and the second support pins 22b are in contact with the lower surface of the coating region A1 of the substrate 9. The coating region A1 is a device region for forming a device, and therefore, the first support pins 22a may be said to be in contact with the lower surface of the non-device region of the substrate 9, and the second support pins 22b may be said to be in contact with the device region of the substrate 9. However, it is not necessarily limited thereto.

Fig. 12 is a diagram showing a second example of the positional relationship between the substrate 9 and the first support pins 22a and the second support pins 22b. In the example of fig. 12, all the first support pins 22a are in contact with the lower surface of the peripheral region B1 of the substrate 9, and all the second support pins 22B are in contact with the lower surface of the inner region B2 of the substrate 9. In contrast, all the first support pins 22a are not abutted against the lower surface of the inner region B2 of the substrate 9, but are provided so as to avoid the inner region B2 of the substrate 9. Similarly, all the second support pins 22B are not abutted against the lower surface of the peripheral edge region B1 of the substrate 9, but are provided so as to avoid the peripheral edge region B1 of the substrate 9.

Accordingly, the thick first support pins 22a are not located directly under the inner region B2 of the substrate 9. Therefore, even if the number, position, and shape of the coating regions A1 are changed in the inner region B2 of the substrate 9, the coating regions A1 of the substrate 9 are supported only by the thin second support pins 22B. Therefore, the region of the substrate 9 where the coating film 90 is formed is supported only by the second support pins 22 b. Therefore, even if the number, position, and shape of the application regions A1 are changed, the occurrence of uneven drying of the application film 90 can be suppressed.

Contact area of support pins 22 and substrate 9

The magnitude relation between the first contact area of the upper end of the first support pin 22a with the second surface F2 that is the lower surface of the substrate 9 and the second contact area of the upper end of the second support pin 22b with the second surface F2 of the substrate 9 is not particularly limited. However, the first contact area of the first support pins 22a with respect to the peripheral edge area B1 of the support substrate 9 may be larger than the second contact area.

Accordingly, the friction force between the first support pins 22a and the peripheral edge region B1 of the substrate 9 can be made larger than the friction force between the second support pins 22B and the substrate 9. Therefore, the thicker first support pins 22a can reduce the amount of offset in the horizontal direction of the substrate 9. On the other hand, if the first contact area is large, the amount of heat transferred between the first support pins 22a and the substrate 9 is relatively large. However, these first support pins 22a support the peripheral region B1 (i.e., the non-coating region A2) of the substrate 9, and thus are less likely to cause variation in temperature distribution in the coating region A1 of the substrate 9.

The second contact area of the second support pins 22b with the substrate 9 is smaller than the second contact area of the first support pins 22a with the substrate 9, so that heat moving between the second support pins 22b and the substrate 9 can be reduced. Although the second support pins 22b support the coating region A1 of the substrate 9, since the amount of movement of heat between the second support pins 22b and the substrate 9 is small, variation in temperature distribution of the coating region A1 can be suppressed. Therefore, the occurrence of uneven drying of the coating film 90 can be suppressed.

Spacing of support pins 22

Next, the pitch between the first support pins 22a and the pitch between the second support pins 22b will be described. Fig. 13 is a diagram showing a third example of the positional relationship between the substrate 9 and the first and second support pins 22a and 22 b. In the example of fig. 13, the first support pins 22a are spaced apart from each other more widely than the second support pins 22b are spaced apart from each other.

The first support pins 22a are thicker than the second support pins 22b, so that the substrate 9 can be properly supported even if the first support pins 22a are set to have a wider pitch than the second support pins 22 b. Conversely, the pitch of the first support pins 22a may be set to be wider than the pitch of the second support pins 22b within a range of the extent to which the substrate 9 is appropriately supported while the displacement in the horizontal direction of the substrate 9 can be suppressed.

Accordingly, the number of the first support pins 22a can be reduced, and the manufacturing cost of the reduced pressure drying apparatus 1 can be reduced. In addition, the upper ends of the support pins 22 can be worn out by contact with the substrate 9. That is, since the support pins 22 are consumable items, the support pins 22 need to be replaced, but the fewer the number of support pins 22 is, the less man-hours the replacement work of the support pins 22 can be made.

Material of support pin 22

The second support pins 22b may be formed of, for example, a porous resin. The porous resin referred to herein means a structure in which the resin contains a plurality of fine pores. Such a porous resin can be produced by foam molding such as supercritical foam molding. For the resin, polypropylene can be applied, for example. The average diameter of the pores formed in the resin may be, for example, several nm or more and several tens of μm or less.

The thermal conductivity of such second support pins 22b is relatively low. The reason for this is that: since the gas in the pores is less likely to transfer heat than the resin, the movement of heat in the second support pins 22b is hindered by the plurality of pores. The thermal conductivity of the second support pin 22b may be, for example, 0.12W/m·k or less.

If the thermal conductivity of the second support pins 22B is small, the amount of heat that moves between the second support pins 22B and the substrate 9 via the contact portion between the second support pins 22B and the inner region B2 of the substrate 9 can be reduced. Therefore, the uniformity of the temperature of the substrate 9 can be further improved. Therefore, uneven drying of the coating film 90 formed in the coating region A1 of the substrate 9 can be further suppressed.

The entire second support pin 22b need not be formed of a porous resin, but for example, at least the second contact portion 23b in the second support pin 22b may be formed of a porous resin. For example, the second contact portion 23b may be formed of a porous resin, and the second cylindrical portion 25b may be formed of a non-porous resin. Thereby, the heat quantity moving between the second support pins 22b and the substrate 9 can also be reduced. Of course, when the entire second support pin 22b is formed of a porous resin, the movement of heat can be further reduced.

The first support pins 22a may be formed of a porous resin in the same manner as the second support pins 22 b. Accordingly, the amount of heat transferred between the first support pins 22a and the substrate 9 via the contact portion between the first support pins 22a and the peripheral edge portion B1 of the substrate 9 can be reduced. Therefore, the amount of deviation in the temperature distribution in the peripheral edge region B1 of the substrate 9 can be reduced. Further, the temperature difference between the peripheral edge region B1 and the inner region B2 of the substrate 9 can be reduced, and the movement of heat between the peripheral edge region B1 and the inner region B2 can be reduced. Therefore, an increase in deviation of the temperature distribution in the end portion in the inside region B2 can be suppressed or avoided.

< 3 modified example >)

The present disclosure is not limited to the above-described embodiment, and various changes, modifications, and the like can be made without departing from the spirit of the present disclosure.

In the above embodiment, at least one of the two or more support pins 22 supporting the peripheral edge region B1 of the substrate 9 may be the first support pin 22a. In other words, several of the two or more support pins 22 supporting the peripheral edge region B1 of the substrate 9 may be the second support pins 22B. In summary, two or more support pins 22 supporting the peripheral region B1 of the substrate 9 may include both the first support pin 22a and the second support pin 22B. If the one or more thick first support pins 22a support the peripheral edge region B1 of the substrate 9, the displacement of the substrate 9 in the horizontal direction can be suppressed. Further, it is desirable that at least half or more of the support pins 22 supporting the peripheral edge area B1 be the first support pins 22a.

In addition, at least one of the two or more support pins 22 supporting the coating region A1 of the substrate 9 may be the second support pin 22b. In other words, some of the two or more support pins 22 supporting the coating region A1 of the substrate 9 may be the first support pins 22a. If one or more thin second support pins 22b support the coating region A1 of the substrate 9, the amount of deviation in the temperature distribution of the coating region A1 can be reduced as compared with a structure in which only the first support pins 22a support the coating region A1. Further, it is desirable that at least half of the support pins 22 supporting the peripheral edge area B1 are the second support pins 22B.

The coating film 90 may be formed on the entire surface of the substrate 9 except the peripheral region B1.

In the above embodiment, the lifting portion 100 for lifting the support portion 20 may not be provided. In this case, the plurality of support pins 22 may be fixed to the chamber 10 such as the upper surface of the bottom surface rectifying plate 40 or the chamber 10 such as the upper surface of the bottom plate 11.

In the illustrated embodiment, for example, the chamber 10 has four exhaust ports 16a, 16b, 16c, 16d, but is not limited thereto. For example, the number of exhaust ports provided in the chamber 10 may be any one of one to three and five or more. For example, the individual valves Va, vb, vc, vd may be omitted.

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

In the above embodiment, the carry-in/carry-out port 14 for the substrate 9 is provided in the side wall portion 12 of the chamber 10, but the present invention is not limited thereto. For example, the four side wall portions 12 and the top plate portion 13 of the chamber 10 may be configured as an integral cover portion, and the cover portion may be separated from the bottom plate portion 11 and retracted upward. In this case, for example, the cover may be moved up and down by the opening/closing drive unit 16 or the like. The chamber 10 can be selectively set to a state (closed state) in which the lid portion is in contact with the bottom plate portion 11 via a sealing material such as an O-ring to seal the internal space 10s, and a state (open state) in which the lid portion is separated upward from the bottom plate portion 11 to open the internal space 10 s. Here, when the chamber 10 is in the open state, the substrate 9 can be carried into the internal space 10s of the chamber 10 and the substrate 9 can be carried out from the internal space 10s of the chamber 10. When the chamber 10 is in the closed state, the coating film 90 on the substrate 9 can be dried by depressurizing by exhausting gas from the internal space 10s and supplying gas to the internal space 10 s.

In the one embodiment, for example, the support portion 20 may have various embodiments. For example, a plurality of support plates 21 may be one support plate 21.

In the illustrated embodiment, for example, there may be no bottom fairing 40 or no side fairing 50.

In the above-described embodiment, for example, various operations in the decompression drying device 1 may be started or ended in response to an operation of the input unit 804 by a user, a signal input to the communication unit 806 from an external device, or the like.

In the above-described embodiment, for example, at least a part of the functional structure to be implemented in the control section 80 may include hardware such as a dedicated electronic circuit.

It is needless to say that all or a part of the above-described one embodiment and various modifications can be appropriately combined within a range not contradictory.

Claims

1. A reduced pressure drying apparatus that dries a coating film formed on an upper surface of a substrate, the reduced pressure drying apparatus comprising:

a chamber for accommodating the substrate;

a plurality of support pins for supporting the substrate from below in the chamber; and

an exhaust unit for exhausting the gas in the chamber,

the plurality of support pins includes one or more first support pins and one or more second support pins thinner than the first support pins,

At least one of the first support pins supports a peripheral region in the substrate from below,

at least one of the second support pins supports, from below, an area in which the coating film is formed in an inner area of the substrate that is further inside than the peripheral area.

2. The decompression drying device according to claim 1, wherein,

the inner region of the substrate is supported only by the second support pins.

3. The decompression drying device according to claim 1, wherein,

at least another one of the first support pins supports an area other than the area where the coating film is formed in the inner area of the substrate.

4. The reduced pressure drying apparatus according to any one of claims 1 to 3, wherein,

the contact area of the first support pin and the substrate is larger than the contact area of the second support pin and the substrate.

5. The reduced pressure drying apparatus according to any one of claims 1 to 4, wherein,

the first support pins have a wider pitch than the second support pins.

6. The reduced pressure drying apparatus according to any one of claims 1 to 5, wherein,

the second support pin has a thermal conductivity of 0.12W/mK or less.

7. The reduced pressure drying apparatus according to any one of claims 1 to 6, wherein,

the second support pin is formed of a porous resin.