JP2003154303A - Vacuum drying device and vacuum drying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a vacuum drying process of a substrate with a high in- plane uniformity, in a technique to vacuum-dry a triangular substrate to which a coating liquid is applied. SOLUTION: In the vacuum-drying device for performing a vacuum-drying process of, for example, a lechicle substrate, to the surface of which a coating liquid is applied, an air flow regulating member which regulates an air flow formed by a solvent vaporized from the coating liquid so that the air flow proceeds in a specified direction, is mounted on an air flow regulating plate installed opposite to the lechicle substrate, with a slight gap left, above the substrate placed on a pedestal inside an airtight container housed in the vacuum- drying device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate reduced-pressure drying apparatus and a substrate reduced-pressure drying method in which a substrate coated with a coating liquid such as a resist is dried under reduced pressure to dry the coating liquid.

[0002]

2. Description of the Related Art In the manufacturing process of semiconductor devices and LCDs, a resist process is performed on a substrate to be processed by a technique called photolithography. In this process, an exposure process is performed by using a reticle substrate having a predetermined mask pattern formed on its surface. First, a mask pattern is formed on the surface of the reticle substrate by applying a predetermined coating on the surface of the glass substrate. This is carried out by a series of steps of applying a liquid to form a liquid film, exposing the liquid film to light, and then developing the liquid film to obtain a desired pattern.

As one of the coating methods of the coating liquid, a coating liquid (resist liquid) formed by mixing a resist component forming a liquid film and a solvent is reciprocated in one direction by a nozzle provided above the reticle substrate. In addition to the above, there is a method of discharging the coating liquid from the nozzle onto the surface of the reticle substrate while intermittently feeding the reticle substrate in a direction intersecting with it, and coating the coating liquid in a so-called one-stroke writing manner.

As a solvent contained in the coating liquid, a solvent having low volatility is used, and the solvent is promptly removed from the substrate surface to ensure the film thickness uniformity of the coating film. In carrying out the above method, it is considered preferable to apply the coating liquid onto the substrate and then immediately carry it into a reduced pressure drying unit to perform reduced pressure drying. Figure 1
FIG. 3 is a view showing a conventional vacuum drying unit. 11 in the figure
Is a closed container 11 composed of a lid 12 and a mounting portion 13.
The opening 12a is formed in the ceiling of the lid 12. The opening 12a communicates with the vacuum pump 14 via the exhaust pipe 12b so that the inside of the closed container 11 can be depressurized. In such an apparatus, the reticle substrate R is placed on the placing part 13, the temperature of the reticle substrate R is adjusted by a temperature adjusting means (not shown), and the vacuum pump 14 is operated to reduce the pressure in the closed container 11. Then, the solvent in the coating liquid on the surface of the reticle substrate R is evaporated (dried), and a pattern is formed by the remaining resist component.

[0005]

By the way, the state of the coating liquid 15 on the surface of the reticle substrate R when conveyed to the reduced pressure drying unit is, for example, as shown in FIG. For example, in the area of about 20 mm inside), the corners are rounded by the surface tension of the coating liquid 15 itself. Therefore, as shown in FIG. 14B, the inside of the hermetically sealed container 11 with the rectifying plate 16 provided so as to face the reticle substrate R above the reticle substrate R mounted on the mounting portion 13. Is depressurized, and the coating liquid 15 is formed by the air flow spreading outward between the rectifying plate 16 and the reticle substrate R.
Has been studied to prevent the coating liquid 15 from spreading toward the peripheral edge of the reticle substrate R and rounding the coating liquid 15 in the peripheral area.

In this case, in the reticle substrate R which is a square or rectangular rectangular substrate, as shown in FIG. 15, there are an air flow in the direction a, which is the diagonal line of the substrate, and an air flow in the direction b, which is the side direction. Then, the strength of the air flow at the peripheral portion of the substrate is different, and in the diagonal direction of the substrate, as shown in FIG. 14C, the air flow for spreading the above-mentioned coating liquid to the outside is weak, and the coating liquid at the peripheral portion is weak. There is a case where 15 is pulled by the reduced pressure exhaust and the film thickness at the peripheral portion becomes extremely high. As described above, when the film thickness varies depending on the region in the peripheral region of the reticle substrate R,
There is a concern that the peripheral area cannot be used as a circuit formation area.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a treatment with high in-plane uniformity in a reduced-pressure drying apparatus for drying a coating film formed on the surface of a rectangular substrate. It is to provide the technology that can do.

[0008]

The vacuum drying apparatus of the present invention is a vacuum drying apparatus for vacuum drying a rectangular substrate having a coating liquid applied on the surface thereof. Part is provided inside the airtight container, a rectifying plate provided so as to face the surface of the substrate placed on the substrate placing part with a gap, a face of the rectifying plate on the substrate side, and the substrate Provided on at least one of the surfaces of the mounting portion,
An air flow restricting member for restricting an air flow formed of a solvent component evaporated from the coating liquid so as to be directed in a predetermined direction, and a pressure reducing member for decompressing the airtight container and evaporating the solvent component contained in the coating liquid. And an exhaust means.

The airflow restricting member is provided, for example, so that the airflow extends along one side of the substrate and the other side facing it. The airflow restricting member is provided along the periphery of the substrate, for example, and is provided at a position corresponding to a corner of the substrate so that the airflow restricted by the airflow restricting member is directed in the extension direction of the diagonal line of the substrate. It may be configured not to include, for example, a first member provided along a diagonal line of the substrate and facing each other across the extension line, and the first member provided along one diagonal line. The end portion near the substrate and the end portion near the substrate of the first member provided along the diagonal line adjacent to the one diagonal line may be connected to each other. Further, the substrate mounting portion may be configured to include a temperature control plate that adjusts the temperature of the substrate and a recessed portion that is provided so that the substrate fits in the temperature control plate.

According to the present invention, when the coating film is dried under reduced pressure with the straightening plate facing the rectangular substrate surface, the air flow regulating member regulates the air flow so that it flows in a predetermined direction. It is possible to form an air flow having no or little unevenness, and it is possible to perform highly uniform treatment.

The reduced-pressure drying method of the present invention comprises a step of placing a rectangular substrate having a coating liquid applied on its surface on a substrate placing portion in an airtight container, and then a rectifying plate on the surface of the substrate via a gap. The inside of the airtight container is depressurized in a state of facing each other, and the air flow formed by the solvent component evaporated from the coating liquid applied to the substrate is regulated in a predetermined direction by the air flow regulating member provided on the rectifying plate. And a process.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Before describing the vacuum drying apparatus of the present invention, an example of a coating apparatus incorporating the vacuum drying apparatus will be described with reference to FIG. 1 in FIG.
Reference numeral 1 denotes a cassette station for carrying in and out a cassette C in which a plurality of reticle substrates R are stored,
The cassette station 21 is provided with a mounting portion 21a on which the cassette C is mounted. Further, on the back side of the cassette station 21, for example, a shelf unit 23, 24, 25 in which a coating unit 22, a heating / cooling system, a unit for drying under reduced pressure, and the like are stacked in multiple stages in order from the left side when the back is seen from the cassette station 21, respectively. It is arranged. Further, the cassette station 21, the coating unit 22
And the reticle substrate R between the shelf units 23, 24, 25.
A transfer mechanism 26 including an arm 26a for delivering and receiving is provided.

The coating unit 22 is provided with a coating device capable of a coating method which will be described later, and the shelf units 23, 24 and 25 include the heating unit 20.
1. In addition to the cooling unit 202, a reduced pressure drying unit 203 which is a reduced pressure drying apparatus of the present invention, a hydrophobic treatment unit 2
04 and so on are assigned vertically. In addition, 201-2
04 is indicated as an example.

The flow of the reticle substrate R of this apparatus will be described. First, the cassette C accommodating the reticle substrate R is placed on the placing portion 21a from the outside, and the reticle substrate R is taken out of the cassette C by the transport mechanism 26. After the hydrophobic processing is performed in the processing section of one shelf of the hydrophobic processing unit 204 in the shelf unit 25, the cooling unit 2
In 02, it is cooled to a predetermined temperature, and in the coating unit 22, a resist liquid which is a coating liquid is applied. Subsequently, the reticle substrate R is conveyed to the reduced pressure drying unit 203, and a resist film is formed by the reduced pressure drying process. The reticle substrate on which the resist film is formed is heated to a predetermined temperature by the heating unit 201, cooled to a predetermined temperature by the cooling unit 202, and returned to the cassette C on the mounting portion 21a. Thereafter, the reticle substrate R stored in the cassette C is conveyed to an exposure device (not shown), the resist film is exposed, and then development processing is performed by a development device to form a desired mask pattern. .

Here, in the above-mentioned coating unit in the preceding stage of the vacuum drying method according to the present invention, a coating liquid (resist liquid RE) formed by mixing a resist component forming a liquid film and a solvent is applied to the surface of the reticle substrate R. A coating method will be briefly described with reference to FIGS. 2 and 3. In the substrate processing space of the coating unit, the coating liquid supply nozzle 30 set to face the front surface side of the reticle substrate R horizontally held by a substrate holding unit (not shown) is moved in one direction (X in the drawing).
The coating liquid is supplied to the reticle substrate R while reciprocating in (direction). In this case, a plate 31 having a slit-shaped opening is provided so as not to be supplied outside the intended coating area. When the supply nozzle 30 moves from one edge of the substrate to the other edge, the reticle substrate R is intermittently fed in a direction intersecting with it by a moving mechanism (not shown) at the timing. By repeating such operation,
The coating liquid is applied to the reticle substrate R in a so-called one-stroke writing manner.

Next, an embodiment of the reduced pressure drying apparatus according to the present invention will be described. As shown in FIG. 4, this reduced-pressure drying apparatus includes a mounting table 4 which is a substrate mounting portion for mounting the reticle substrate R coated with the coating liquid. A temperature controller 41 for adjusting the temperature of the mounted reticle substrate R, for example, a cooling unit made of a Peltier device is embedded in the mounting table 4. In this example, the temperature is controlled by the mounting table 4 and the temperature controller 41. The adjustment plate is configured. Regarding the mounting table 4 in more detail, as shown in FIGS.
The substrate mounting area of the mounting table 4 is formed by a similar-shaped recess 42 (substrate accommodating portion) slightly larger than the reticle substrate R so that the temperature of the reticle substrate R having a relatively large heat capacity can be quickly adjusted. With this structure, heat exchange is promptly performed on the back surface and the side surface of the substrate. Further, it is possible to minimize the substrate temperature change when the solvent is evaporated (evaporated).
On the bottom surface of the concave portion 42, the reticle substrate R accommodated in the concave portion 42 is mounted on the four corners of the reticle substrate R so that the reticle substrate R can be mounted with a slight gap from the surface of the mounting table 4, for example, about 0.1 mm. The protrusion 43 for holding the substrate is provided at the corresponding position.
Is provided. Further, when the reticle substrate R is carried in and out of the mounting table 4, the chamfered portion 44 at the peripheral edge of the reticle substrate R is provided with a substrate supporting surface 45 inclined like the chamfered portion so as to support the chamfered portion 44 from below and move up and down. Board support pin 4
6 penetrates the mounting table 4 in the vertical direction and is provided so as to be able to project and retract by an elevating mechanism (not shown).

A lid 5 is provided on the upper side of the mounting table 4 so as to be lifted and lowered by a lid lifting mechanism (not shown). The lid 5 is raised when the reticle substrate R is loaded and unloaded, and is lowered when the reticle substrate R is dried, so that the lid 5 and the mounting table 4 form an airtight container 40. An exhaust port 51 is provided near the center of the ceiling of the lid 5, and a valve 52 is provided at the exhaust port 51, a pressure adjusting unit 53 that adjusts the exhaust flow rate to control the pressure, and a vacuum pump that is a decompression exhaust unit. 54 is connected via a pipe 55.

A rectifying plate 6 is provided above the mounting table 4 so as to face the surface of the reticle substrate R.
As shown in FIG. 7, the current plate 6 is formed of, for example, a circular plate having a larger surface area than the surface area of the reticle substrate R, and the surface opposite to the front surface of the reticle substrate R (back surface side) has a peripheral edge of the reticle substrate R. On the other hand, slightly outside, for example, 20 so as to extend along both sides R1 and R2 at positions corresponding to one side R1 of the substrate and the other side R2 facing it.
0 mm (length) x 10 mm (width) x 0.8 mm (thickness)
The rectangular airflow restricting members 61 are provided respectively. Further, the rectifying plate 6 is supported by a supporting member 62 at its peripheral portion at, for example, three places, and these supporting members 62 penetrate the mounting table 4 and are connected via an elevating base 63 to elevating means 6
The height can be adjusted according to item 4.

In the elevating means 64, a ball screw portion 66 screwed with a guide portion 65 is arranged below the elevating base 63, and the ball screw portion 66 is rotated by a driving portion including a motor M and a pulley 67. The guide member 65 and the connecting body 68 whose both ends are pivotally supported by the elevating base 63 rotate so that the flow straightening plate 6 moves up and down.
In addition, 69 is the airtight container 40 through the through hole of the support member 62.
It is a bellows to prevent the decompressed state inside from being broken. The motor M, the temperature adjusting means 41, and the pressure adjusting unit 53 are connected to the control unit 7, and when the reticle substrate R is dried under reduced pressure, its operation is controlled by the control unit 7.

In such a reduced-pressure drying apparatus, the reticle substrate R coated with the coating liquid by the above-described method is first operated in a state in which the lid 5 is lifted and the cooperation between the transport arm (not shown) and the substrate support pin 46. Due to the action, the concave portion 4 of the mounting table 4
It is placed so that it fits in 2. Next, the rectifying plate 6 is lowered to the standby position by the elevating means 64, and the lid 5 is lowered to form the airtight container 40 surrounding the reticle substrate R.
Then, the current plate 6 descends to a first height position L1, for example, a height position where the lower surface of the current plate 6 is 1 mm away from the surface of the reticle substrate R (the lower surface of the airflow regulating member is 0.2 mm away from the surface of the reticle substrate R. The temperature of the reticle substrate R is set to a predetermined temperature, for example, 18 ° C. by the temperature adjusting means 41.

Then, the valve 52 is opened and the vacuum pump 5 is opened.
4, the depressurization of the airtight container 40 is started, and the air in the airtight container 40 is first discharged as shown by the solid line in the graph showing the relationship between the depressurization time t and the pressure p in the airtight container 40 shown in FIG. The pressure p rapidly decreases until the reduced pressure time t1. Next, the coating liquid (resist liquid R
Evaporation of the solvent contained in E) starts, and an airflow that flows through the gap between the reticle substrate R and the current plate 6 is formed. At this time, since the solvent has a large volume in the gap due to evaporation (change of state from liquid to gas), the air flow flows so as to spread the resist film on the surface of the reticle substrate R outward. Further, in order to prevent the solvent from boiling and roughening the surface of the coating liquid film, the exhaust amount is adjusted by the pressure adjusting unit 53, and the pressure p in the airtight container 40 is the vapor of the solvent as shown in FIG. 8B. Gradually decreases near the pressure side.

At this time, as shown in FIG. 9A, while the flow direction is regulated by the flow straightening plate 6 and the air flow regulating member 61, the air flow flowing outward in a slight gap between the flow straightening plate 6 and the reticle substrate R. It is formed. That is, since the gap between the lower surface of the air flow restricting member 61 and the reticle substrate R is extremely small, the space above the reticle substrate R is surrounded by the pair of air flow restricting members 61 and 61 extending to both sides of the reticle substrate R and the flow straightening plate 6. The front and back are open,
Therefore, most of the air flow containing the solvent vapor evaporated from the coating film on the reticle substrate R has a front opening or a rear opening, as schematically shown by the size of the arrow in FIG. And a uniform airflow is formed over the entire surface of the reticle substrate R.

If the vacuum drying is continued as it is, the reticle substrate R may be dried in a state where the film thickness at the peripheral edge becomes high. Therefore, when the pressure p in the hermetic container 40 reaches a predetermined pressure (see FIG. At middle t2), as shown in FIG. 8C, the rectifying plate 6 is moved to the second height position L2, for example, the lower surface of the rectifying plate 6 is moved up to a height position 5 mm away from the surface of the reticle substrate R, and the rectifying plate 6 is moved. By widening the gap between the reticle substrate R and the reticle substrate R, the force of the air flow to spread the coating liquid film is weakened. Thereafter, when most of the solvent evaporates and a resist film made of a resist component is formed on the substrate surface, the airtight container 40
The evaporated solvent atmosphere remaining therein is exhausted, the pressure p in the airtight container 40 rapidly decreases again, and when the pressure reaches a predetermined pressure (t3 in the figure), the reduced pressure exhaust is stopped. Then, the airtight container 40 is returned to the atmosphere, and the reduced pressure drying process is completed.

According to the above-described embodiment, the air flow formed by the solvent component (evaporation component) from the coating film at the time of drying under reduced pressure is guided by the pair of air flow control members 61, 61 along both side edges of the reticle substrate R. By setting the flow, it is possible to form a uniform air flow to the peripheral edge of the reticle substrate R. Further, since a part of the airflow flows under the airflow restricting members 61, 61 from both side edges of the reticle substrate R, the coating liquid can be prevented from being rounded by the surface tension even at both side edges (peripheries along the X direction). As a result, the reticle substrate R
The swelling state of the coating film in the peripheral portion over the entire circumference is within a predetermined range, and local abnormal swelling due to a small flow rate in the corner portion of the reticle substrate R can be suppressed. The effective area in can be widened. That is, according to this embodiment, the reticle substrate R can be subjected to reduced-pressure drying treatment with high in-plane uniformity.

As another embodiment, the air flow restricting member 61 may be so structured as to restrict the air flow so as to extend in the direction of extension of the diagonal line of the reticle substrate R. For example, in FIG.
As shown in (a), the airflow regulating members 61 are not provided in the regions corresponding to the four corners of the substrate, and the regions are so-called open, and the airflow regulating members 61 are provided at the positions corresponding to the respective sides of the substrate. May be provided. Alternatively, FIG.
As shown in (b) or FIG. 10 (c), a pair of first members 6 provided along the diagonal extension line d1 of the reticle substrate R and facing each other with the extension line d1 interposed therebetween.
1a and an extension line d of a diagonal line adjacent to the diagonal line
The configuration may be such that the end of the first member 61a provided along the line 2 is connected. In this example, FIG.
Then, the second member 61 provided along the peripheral direction of the substrate
The end portion of the first member 61a near the substrate is connected via b. Further, in FIG. 10C, the extension line d of each diagonal line from the vicinity of the center of each side of the reticle substrate R.
1, the first member 61a extends outward so as to extend in parallel with d2, and the two first members 61a are provided on each side.
Four sets of dogleg-shaped airflow restricting members 61 are formed by a and 61a.

In such a structure, the reticle substrate R
The airflow in the diagonal direction can be strengthened, while the airflow in the side direction can be weakened. That is, the strength of the airflow can be made uniform and high over the entire periphery of the reticle substrate R, and the same effect as the above case can be obtained. Further, the current plate 6 is not limited to the circular shape and may be a quadrangular shape. In this case, the same effect as the above case can be obtained. The present invention can also be applied to a substrate other than the reticle substrate, for example, a glass substrate for LCD under reduced pressure as a substrate to be processed.

Further, the vacuum drying device of the present invention comprises an airtight container 4
As a means for releasing the reduced pressure state of 0, as shown in FIG. 11, a gas supply means including a valve 81, a pressure adjusting portion 82, and a filter 83 may be connected via a three-way valve 84. In this case, the valve 81 is opened after the coating liquid applied to the surface of the reticle substrate R is dried,
The three-way valve 84 is switched to supply a purging gas, for example, an inert gas such as nitrogen gas, which is set to have a predetermined air supply amount by the pressure adjusting means 82, into the airtight container 40 in a reduced pressure state, and the airtight container 40. The internal pressure is returned to the atmosphere.
In such a configuration, it is possible to supply the gas from which impurities such as suspended particles have been removed by the filter 83, and even if the impurities adhere to the airtight container 40, the impurities will not flow into the gas flow. Since the supply amount of air is set so that it does not wind up in the airtight container 40 and is supplied, it is possible to prevent impurities from adhering to the substrate.

The air flow regulating member 61 is the above-mentioned rectifying plate 6
The configuration is not limited to that provided in FIG. 12, and as shown in FIG. 12, for example, a configuration in which the airflow regulating member 61 as shown in FIGS. It may be configured to be divided into two.
Even in such a configuration, the airflow can be regulated in a predetermined direction, and the same effect as the above case can be obtained.

[0029]

As described above, according to the present invention, in a vacuum drying apparatus for drying a coating film formed on the surface of a rectangular substrate, a solvent component (evaporation component) from the coating film is used during drying under reduced pressure. By controlling the direction of the formed airflow to form an even airflow, a highly uniform vacuum drying process can be performed, and as a result, the in-plane uniformity of the coating film can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a coating apparatus incorporating a reduced pressure drying apparatus according to the present invention.

FIG. 2 is a perspective view schematically showing a coating device for forming a coating film which is a target of a reduced pressure drying process.

FIG. 3 is an explanatory diagram showing a state of forming a coating film which is a target of a reduced pressure drying process.

FIG. 4 is a vertical sectional view showing a reduced pressure drying apparatus according to an embodiment of the present invention.

FIG. 5 is a perspective view showing a mounting table of the reduced pressure drying apparatus according to the above embodiment.

FIG. 6 is a cross-sectional view showing how the substrate is supported on the mounting table.

FIG. 7 is an explanatory diagram showing a current plate used in the reduced pressure drying apparatus according to the above embodiment.

FIG. 8 is a process diagram showing a reduced pressure drying process of the reduced pressure drying apparatus according to the above embodiment.

FIG. 9 is an explanatory diagram illustrating the flow of airflow during reduced pressure drying.

FIG. 10 is an explanatory diagram showing another example of the current plate used in the present invention.

FIG. 11 is a vertical cross-sectional view showing a preferable purge gas supply system used in the reduced pressure drying apparatus according to the embodiment of the present invention.

FIG. 12 is an explanatory diagram showing another configuration example of the air flow restricting member used in the present invention.

FIG. 13 is an explanatory diagram showing a conventional vacuum drying device.

FIG. 14 is an explanatory diagram showing a state of a coating film on a peripheral portion of a substrate when a conventional vacuum drying device is used.

FIG. 15 is an explanatory diagram showing the flow of airflow when a conventional reduced-pressure drying device is used.

[Explanation of symbols]

R reticle substrate 4 table 40 airtight container 41 Temperature control means 42 recess 5 Lid 51 Pressure regulator 54 vacuum pump 6 current plate 61 Air flow control member 61a First member of air flow regulating member 61b Second member of air flow regulating member 73 Filter

[Procedure amendment]

[Submission date] November 26, 2001 (2001.11.
26)

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 5]

[Figure 6]

[Figure 10]

[Figure 4]

[Fig. 13]

FIG. 15

[Figure 7]

[Figure 8]

FIG. 11

[Figure 9]

[Fig. 12]

FIG. 14

Continued front page    (72) Inventor Shinichi Sugimoto             TBS release, 5-3-6 Akasaka, Minato-ku, Tokyo             Sending Center Tokyo Electron Limited (72) Inventor Koji Sakai             TBS release, 5-3-6 Akasaka, Minato-ku, Tokyo             Sending Center Tokyo Electron Limited F term (reference) 2H025 AB14 AB16 AB20 DA20 EA10                 3L113 AA03 AB10 AC24 BA34 CB23                       DA11                 4D075 BB24Z BB56Z BB93Z CA48                       DA06 DB13 DC19 DC22 EA07                       EA45                 4F042 AA02 AA07 AB00 BA06 BA16                       BA27 DB01 DB17 DC01 DE01                       DE07 DE09 DF07                 5F046 JA02 JA22 JA27 KA04

Claims (6)

[Claims] 1. A vacuum drying apparatus for vacuum-drying a rectangular substrate having a coating liquid applied on its surface, wherein an airtight container having a substrate mounting portion for mounting the substrate therein, A rectifying plate provided so as to face the surface of the substrate placed on the substrate placing part with a gap, and provided on at least one of the surface of the rectifying plate on the substrate side and the surface of the substrate placing part. An air flow restricting member for restricting the air flow formed by the solvent component evaporated from the coating liquid so as to be directed in a predetermined direction, and depressurizing the airtight container to evaporate the solvent component contained in the coating liquid. A reduced pressure drying apparatus, comprising: a reduced pressure exhaust unit. 2. The reduced-pressure drying apparatus according to claim 1, wherein the air flow regulating member is provided so that the air flow extends along one side of the substrate and the other side facing the substrate. 3. The airflow regulating member is provided along the peripheral edge of the substrate, and is provided at a position corresponding to a corner of the substrate such that the airflow regulated by the airflow regulating member is directed in the extension direction of the diagonal line of the substrate. 2. The reduced pressure drying apparatus according to claim 1, wherein is not provided. 4. The airflow control member includes first members facing each other along an extension line of a diagonal line of the substrate and sandwiching the extension line, the first member being provided along one diagonal line. 2. The end portion near the substrate and the end portion near the substrate of the first member provided along the diagonal line adjacent to the one diagonal line are connected to each other. Vacuum dryer. 5. The substrate placing section includes a temperature control plate for adjusting the temperature of the substrate, and a recessed portion provided in the temperature control plate so that the substrate fits in the temperature control plate.
5. The reduced pressure drying apparatus according to any one of 1 to 4. 6. A step of placing a rectangular substrate having a surface coated with a coating liquid on a substrate placing portion in an airtight container, and then airtight with a current plate facing the substrate surface with a gap therebetween. A step of decompressing the inside of the container and regulating the air flow formed by the solvent component evaporated from the coating liquid applied to the substrate so as to be directed in a predetermined direction by an air flow regulating member provided on the rectifying plate. A method for drying under reduced pressure, which is characterized in that