TW201710634A - Decompression drying device and decompression drying method capable of providing a stable decompression drying process for simultaneously performing decompression and heating in a short period of time - Google Patents

Abstract

The subject of the present invention is to provide a stable decompression drying process for simultaneously performing the decompression and heating in a short period of time. The decompression drying device of the present invention receives the substrate in the internal space of a chamber and, at the same time, the ambient gas of the internal space is discharged through an exhaust pipe connected with the chamber, so as to decompress and heat the internal space. Thus, the solvent component contained in the coating film on the substrate is vaporized to dry the coating film. Moreover, there is a pipe heating portion provided for heating the exhaust pipe. The present invention also provides a decompression drying method.

Description

Vacuum drying device and vacuum drying method

The present invention relates to a glass substrate for a liquid crystal display device, a semiconductor wafer, a glass substrate for a plasma display panel (PDP), a glass substrate for a mask, a substrate for a color filter, and a recording disk. A vacuum drying apparatus and a vacuum drying method for drying a coating film on a substrate for a precision electronic device such as a substrate for a solar cell or a substrate for an electronic paper (hereinafter simply referred to as "substrate").

In the manufacturing step of the substrate for a precision electronic device, in order to dry the coating film formed on the surface of the substrate, the solvent component contained in the coating film is vaporized by a reduced pressure treatment to be dried. Decompression drying technology. However, as the coating film becomes thicker, the time required for drying under reduced pressure is prolonged, so that a more efficient vacuum drying technique is desired. In order to satisfy the above-mentioned requirements, a vacuum drying apparatus which performs heat treatment simultaneously with a pressure reduction process has been proposed (for example, refer patent document 1).

The vacuum drying apparatus has a chamber in which a substrate on which a coating film is formed is housed in an internal space thereof. Further, the vacuum drying apparatus has a function of decompressing the internal space and a function of heating the internal space, and the pressure reduction drying time of the coating film is shortened by simultaneously performing the pressure reduction treatment and the heat treatment. [Prior Art Document] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2008-202930

[Problems to be Solved by the Invention] However, when the pressure reduction treatment and the heat treatment are simultaneously performed, the solvent component contained in the coating film is vaporized in a large amount in a short time, and the gas is connected to the chamber through the exhaust pipe. The internal space is discharged. In Patent Document 1, the exhaust pipe is placed at a normal temperature, and various problems may occur as described in the following experiments and analyses. For example, it is difficult to shorten the time required for the decompression drying process, that is, a so-called tact time. Further, the tact time fluctuates every time the vacuum drying treatment is performed, and the decompression drying treatment becomes unstable.

The present invention has been made in view of the above problems, and it is an object of the invention to provide a vacuum drying apparatus and a vacuum drying method which can perform a vacuum drying treatment in which a reduced pressure and a heating are simultaneously performed in a short time and stably. [Technical means to solve the problem]

According to one aspect of the present invention, in a vacuum drying apparatus, while accommodating a substrate in an internal space of a chamber, the internal space is decompressed by discharging an ambient gas in the internal space through an exhaust pipe connected to the chamber, and The inside space is heated to vaporize the solvent component contained in the coating film on the substrate to dry the coating film. The vacuum drying apparatus includes a piping heating unit that heats the exhaust pipe. .

Furthermore, another aspect of the present invention provides a vacuum drying method, comprising: a housing step of housing a substrate on which a coating film is formed in an internal space of a chamber; and a drying step of exhausting the chamber The piping discharges the ambient gas in the internal space, decompresses the internal space, and heats the internal space, thereby vaporizing the solvent component contained in the coating film on the substrate to dry the coating film; and piping heating step The exhaust pipe is heated simultaneously with the drying step. [Effects of the Invention]

When not only the pressure reduction treatment but also the heat treatment is performed in the internal space of the chamber, the solvent component is efficiently vaporized from the coating film on the substrate, and is discharged from the chamber through the exhaust pipe. When the exhaust pipe is at a normal temperature level at the time of discharge, the vaporized solvent component is liquefied and adheres to the exhaust pipe. However, in the present invention, since the exhaust pipe is heated, the liquefaction of the solvent component is suppressed, so that the coating film can be dried in a short time and stably.

Fig. 1 is a longitudinal cross-sectional view showing a configuration of an embodiment of a reduced-pressure drying apparatus according to the present invention. 2 is a block diagram showing the configuration of the reduced-pressure drying device shown in FIG. 1. The vacuum drying apparatus 1 is a device that vaporizes a solvent component contained in a coating film 92 obtained by applying a coating liquid onto the upper surface 91 of the substrate 9 to dry the coating film 92. For example, when a polyimide film is formed on the upper surface 91 of the substrate 9, a precursor of polyimine will be made using an organic solvent such as N-methyl-2-pyrrolidone (NMB). (precursor) A polyamic acid solution in which polyamic acid is dissolved is used as a coating liquid. The coating liquid is applied to form about 10 times of a desired thickness (for example, when a polyimide film having a thickness of about 5 [μm] to 10 [μm] is formed, it is about 50 [μm] to 100 [μm]) A relatively thick coating film. Then, the solvent component contained in the coating film is vaporized and removed by the vacuum drying apparatus 1, and then heated at a high temperature by a heating device different from the vacuum drying apparatus 1 to imidize the yttrium. This forms a polyimide film on the upper surface 91 of the substrate 9. As described above, the vacuum drying apparatus 1 of the present invention can dry the relatively thick coating film 92 under reduced pressure, and is particularly suitable for the case where a large amount of solvent components are vaporized during the vacuum drying treatment.

As shown in FIG. 1, the vacuum drying apparatus 1 includes a chamber 10, a substrate holding unit 20, a substrate heating unit 30, an exhaust unit 40, a piping heating unit 50, and a control unit 60 (FIG. 2) that controls the entire apparatus.

The chamber 10 is a pressure-resistant container including an internal space SP for performing a vacuum drying treatment (=pressure reduction treatment + heat treatment) on the substrate 9. The chamber 10 includes a base portion 11 and a lid portion 12 that are separable from each other. The base portion 11 is fixedly disposed on a device frame (not shown). Further, a chamber elevating mechanism 12a conceptually shown in Fig. 1 is connected to the lid portion 12. Therefore, the chamber elevating mechanism 12a operates in accordance with the lifting command from the control unit 60, whereby the lid portion 12 moves up and down with respect to the base portion 11. When the lid portion 12 is lowered, the base portion 11 is formed integrally with the lid portion 12, and an internal space SP (processing space of the substrate 9) is formed inside. In the present embodiment, an O-ring 13 including a rubber or the like is provided on the peripheral portion of the upper surface of the base portion 11. Therefore, when the lid portion 12 is lowered, an O-ring 13 is interposed between the upper surface of the base portion 11 and the lower surface of the lid portion 12, and the internal space SP of the chamber 10 is in an airtight state. On the other hand, when the lid portion 12 is raised, the chamber 10 is opened, so that the substrate 9 can be carried into the chamber 10 and the substrate 9 can be carried out from the chamber 10.

The substrate holding portion 20 is a mechanism for holding the substrate 9 in the internal space SP of the chamber 10. The substrate holding portion 20 includes a plurality of substrate holding pins 21, and the head portions of the respective substrate holding pins 21 abut against the lower surface of the substrate 9, thereby supporting the substrate 9 in a horizontal posture. The plurality of substrate holding pins 21 are erected on one of the support members 22 disposed outside the chamber 10, and are respectively protruded through the base portion 11 and the substrate heating portion 30 to be protruded from the internal space SP of the chamber 10.

On the support member 22, as shown in Fig. 1, a pin lifting mechanism 22a is connected. Therefore, the pin lifting mechanism 22a operates in accordance with the lifting command from the control unit 60, whereby the support member 22 and the plurality of substrate holding pins 21 move up and down as a whole. In the vacuum drying apparatus 1, while the substrate 9 is held by the plurality of substrate holding pins 21, the pin lifting mechanism 22a is operated, whereby the height position of the substrate 9 with respect to the substrate heating portion 30 can be adjusted.

The substrate heating unit 30 is disposed at a central portion of the upper surface of the base portion 11 . In the substrate heating unit 30, a plurality of rod heaters serving as heating sources are provided. When the rod heater is operated in advance based on the heating command from the control unit 60 before the substrate 9 is carried into the plurality of substrate holding pins 21, the internal space SP is heated before the substrate 9 is loaded, and the loaded substrate 9 is loaded. Heating is performed from the lower surface side thereof. As described above, the substrate 9 is heated in the internal space SP where the ambient temperature rises to vaporize the solvent component from the coating film 92.

Further, in the present embodiment, the exhaust unit 40 is provided in order to perform the pressure reduction process simultaneously with the heat treatment. The exhaust unit 40 includes an exhaust pipe 41 for sucking and discharging a gas containing a solvent component (hereinafter referred to as “exhaust gas”) from the internal space SP of the chamber 10; a butterfly valve 42; The butterfly valve 43 is for controlling the amount of exhaust gas discharged from the chamber 10 via the exhaust pipe 41; the opening and closing valve 44; and the exhaust pump 45. In the present embodiment, two exhaust ports 111 and 112 are provided in the peripheral portion of the base portion 11. Further, in correspondence with the provision of the two exhaust ports as described above, one end portion of the exhaust pipe 41 is branched, and the branch end portion 411 and the branch end portion 412 are connected to the exhaust port 111 and the exhaust port 112, respectively. Further, the butterfly valve 42 and the butterfly valve 43 are interposed between the branch end portion 411 and the branch end portion 412 at positions near the exhaust port 111 and the exhaust port 112, respectively. On the other hand, the other end portion of the exhaust pipe 41 is connected to an exhaust line (not shown) via the opening and closing valve 44 and the exhaust pump 45. Therefore, when the opening and closing valve 44 is opened in accordance with the opening and closing command from the control unit 60, and the exhaust pump 45 is operated in accordance with the operation command from the control unit 60, it corresponds to the opening degree of the butterfly valve 42 and the butterfly valve 43. The amount of exhaust gas discharges the exhaust gas to the exhaust line via the exhaust pipe 41.

In the present embodiment, the pipe heating portion 50 is provided in the exhaust pipe 41. In the pipe heating unit 50, a rubber heater is wound around the outer circumferential surface of the exhaust pipe 41 as the pipe heater 51. The pipe heater 51 generates heat based on a heating command from the control unit 60, thereby heating the exhaust pipe 41. Further, as the pipe heater 51, in addition to the rubber heater, a ribbon heater, a cable heater, a sheet heater, or the like may be used.

Further, in order to adjust the exhaust pipe 41 with high precision, in the present embodiment, as shown in FIG. 2, a pipe temperature sensor 41a that detects the temperature of the exhaust pipe 41 is provided, which is related to the detected temperature. The detected detection signal is output to the control unit 60. Then, the control unit 60 performs feedback control of the piping heating unit 50 based on the temperature of the exhaust pipe 41, and adjusts the temperature of the exhaust pipe 41 to suppress the contact of the solvent components contained in the exhaust gas. Liquefaction occurs to the exhaust pipe 41. As described above, in the present embodiment, the control unit 60 functions as the "pipe temperature control unit" of the present invention. In the following, the technical significance of temperature adjustment by heating the exhaust pipe 41 by the pipe heating unit 50 will be described with reference to FIGS. 3 and 4 before the operation of the vacuum drying apparatus 1 configured as described above.

Fig. 3 is a graph showing the pressure reduction characteristics in the vacuum drying apparatus shown in Fig. 1, and the pressure reduction characteristics were obtained by the following experiment. In the initial stage of the vacuum drying treatment, the solvent component is rapidly vaporized from the coating film 92, and the pressure reduction operation is performed with the amount of exhaust gas balanced therewith. Therefore, the pressure in the chamber 10 is lowered, and the pressure is gradually reduced with the advancement of the reduced-pressure drying treatment, and the vacuum drying treatment of the coating film 92 is completed. Therefore, in the present experiment, all the conditions except the conditions in which the pipe heater 51 is turned "ON"/OFF (OFF) are set in the same manner, and the three substrates 9 are continuously subjected to a reduced-pressure drying process, and each measurement is performed. The change in pressure in the chamber 10 from the fixed value Ps (at atmospheric pressure (100000 Pa) in the experiment) to the completion of the vacuum drying treatment of the coating film 92 was completed. The upper waveform in FIG. 3 shows the decompression characteristics when the pipe heater 51 is not operated (OFF), and the lower waveform shows the decompression characteristics when the pipe heater 51 is operated (at the time of ON).

In the vacuum drying apparatus 1, since the exhaust gas containing the solvent component generated in the chamber 10 is discharged from the chamber 10 through the exhaust pipe 41, the pressure in the chamber 10 decreases as time passes. Here, there are three points that should be of interest in the decompression characteristics shown in FIG.

First, the first point is that in the initial stage of pressure reduction, the case where the pipe heater 51 is kept in the OFF state (substantially equivalent to the conventional device, hereinafter referred to as "conventional example") has a pressure drop rate higher than that of the pipe heater. An example in which the 51 is maintained in the ON state (corresponding to the present embodiment, hereinafter referred to as "the embodiment"). The creator of the present application analyzes the reason that the solvent component contained in the exhaust gas is liquefied by rapid cooling in the exhaust gas pipe 41, and the liquefied solvent component is again vaporized and discharged. . In other words, in the embodiment, the pipe heater 51 is turned on, and the portion that has been liquefied and adhered to the exhaust pipe 41 in the conventional example is also vaporized in the embodiment. The state, and accordingly, the amount that should be discharged is also increased. That is, in the embodiment, the amount of the exhaust gas to be discharged is larger than that of the conventional example, and therefore it is considered that the exhaust gas velocity is slow at the initial stage of the pressure decrease. The pressure characteristics as described above are closely related to the temperature of the exhaust pipe 41.

The second point of interest is that, as described above, the exhaust gas velocity decreases as the temperature of the exhaust pipe 41 rises. However, in the conventional example, the pressure reduction speed decreases after the middle of the pressure decrease, and the vacuum drying process is completed. The previous time is longer than the embodiment. Here, regarding the main factor of the decrease in the decompression speed in the prior art, the creator of the present application analyzes as follows. That is, when observing the waveform of the upper stage of Fig. 3, the pressure in the chamber 10 drops sharply just before reaching a certain pressure Pv, and only after a fixed time at the pressure Pv, the decompression speed becomes substantially zero, and the pressure is again decline. The creator of the present application analyzes the reason that the solvent component contained in the exhaust gas is rapidly cooled and liquefied in the exhaust pipe 41 in the same manner as described above, and the liquefied solvent component is again vaporized and discharged. Further, it can be analyzed that by heating the exhaust pipe 41, it is possible to suppress liquefaction of the solvent component in the exhaust pipe 41, thereby preventing a decrease in the decompression speed, and the analysis results are in agreement with the experimental results. In other words, by heating the exhaust pipe 41, it is possible to prevent the solvent component in the exhaust gas from being liquefied in the exhaust pipe 41, thereby shortening the time required for the vacuum drying process, that is, the so-called tact time.

Further, the third concern is the stability of the vacuum drying treatment. As shown in FIG. 3, in the conventional example, the end timing Toff of the reduced-pressure drying is different each time the vacuum drying treatment is performed. That is, the tact time changes. The reason for this can be analyzed as follows. As described above, the solvent that has once been liquefied in the exhaust pipe 41 is vaporized again. Therefore, it is considered that if the partially vaporized portion is also discharged, it is ended in the first block, the second block, and the third block. The timing Toff does not produce a difference. However, when the pipe heater 51 is maintained in the OFF state, when the pressure is changed to the pressure Pv, a large amount of the vaporized solvent may be liquefied again and adhered to the exhaust pipe 41, whereby the decompression speed becomes slow. Further, when the pressure is lowered below the pressure Pv, it is considered that the solvent which is reliquefied is completely vaporized, but the drying process is continued while the pressure is lowered below the pressure Pv, so that re-liquefaction adhesion continues to occur. As a result, it is considered that the amount of adhesion increases each time the number of blocks increases, and accordingly, the end timing Toff constantly deviates. On the other hand, in the embodiment, the end timing Ton is substantially the same, that is, the tact time is substantially constant. This is considered to be because the pipe heater 51 is in an ON state, and liquefaction does not occur in the heated exhaust pipe 41. In fact, in the examples, as long as the lower waveform of Fig. 3 was observed, the liquefaction of the solvent component was not observed, and the tact time was stable. As described above, the heating of the exhaust pipe 41 is also helpful for stabilizing the vacuum drying process.

Based on the three points of interest and the analysis results, the creator of the present application has reached a conclusion that the heating of the exhaust pipe 41 in the vacuum drying process achieves a shortening of the tact time and stabilization of the decompression drying process. The aspect plays an important role. Further, from the viewpoint of preventing the solvent component from being liquefied in the exhaust pipe 41, it is preferable to adjust the exhaust pipe 41 to a temperature higher than the dew point temperature of the exhaust gas. Here, the "dew point temperature (or simply referred to as "dew point") means that the solvent component is easily liquefied when the temperature of the exhaust gas is equal to or lower than the dew point temperature, and the temperature of the pipe is maintained above the dew point temperature. It is possible to prevent liquefaction of the solvent component contained in the exhaust gas. When the heating temperature of the exhaust pipe 41 is too high, the exhaust gas in the exhaust pipe 41 expands and the exhaust speed decreases. Therefore, the temperature of the exhaust pipe 41 is desirably set lower than that of the chamber 10. Internal space SP.

Here, in the vacuum drying apparatus 1 shown in FIG. 1, it is difficult to directly detect the dew point temperature. Therefore, in the present embodiment, the pressure Pv (the pressure in the chamber 10 at the time of liquefaction is considered to be generated) and FIG. 4 are shown in FIG. The vapor pressure curve of the solvent sets the temperature of the exhaust pipe 41. In other words, the temperature TPv corresponding to the pressure Pv is obtained based on the vapor pressure curve, and the control unit 60 drives the pipe heater 51 to perform the exhaust pipe 41 within a range of ±20 [° C.] of the temperature TPv. heating. Specifically, the temperature of the exhaust pipe 41 in the vacuum drying process is previously stored in the control unit 60 as the target pipe temperature, and the control unit 60 performs the various parts of the vacuum drying apparatus 1 in accordance with the program for the vacuum drying process. Control, thereby performing the following actions.

Fig. 5 is a flow chart showing the operation of the vacuum drying apparatus shown in Fig. 1 . When the substrate 9 is processed by the vacuum drying apparatus 1, the substrate heating unit 30 receives a heating command from the control unit 60 in advance to operate the rod heater to increase the ambient temperature in the internal space SP (step S1: Heating preparation step). In addition, the heating process of the exhaust pipe 41 is started in advance (step S2: pipe heating step), that is, the pipe heating unit 50 receives the heating command from the control unit 60 in advance to operate the pipe heater 51 from the exhaust pipe 41. The outer peripheral surface side is heated to raise the temperature of the exhaust pipe 41. Here, the control unit 60 monitors the temperature of the exhaust pipe 41 detected by the pipe temperature sensor 41a, and performs feedback control based on the temperature to bring the exhaust pipe 41 to the target pipe temperature. Thereby, the temperature of the exhaust pipe 41 in the vacuum drying process is maintained at the target pipe temperature. After the steps S1 and S2 are performed as described above, the substrate 9 coated with the coating film 92 on the upper surface 91 is carried into the chamber 10 and stored in the internal space SP (step S3: carrying in step). Specifically, the lid portion 12 of the chamber 10 is raised by the chamber elevating mechanism 12a. Then, the substrate 9 is carried into the inside of the chamber 10 by a transfer robot (not shown), and placed on the plurality of substrate holding pins 21. When the loading of the substrate 9 is completed, the transfer robot retreats to the outside of the chamber 10, and the lid portion 12 of the chamber 10 is lowered by the chamber elevating mechanism 12a. Thereby, the internal space SP becomes a sealed space.

In the next step S4, the opening and closing valve 44 is opened, and the butterfly valve 42 and the butterfly valve 43 are opened to a predetermined opening degree. Further, the exhaust pump 45 is operated to forcibly discharge the gas inside the chamber 10 through the exhaust port 111 and the exhaust port 112. Thereby, the ambient gas in the internal space SP is discharged to the exhaust line via the exhaust port 111, the exhaust port 112, the butterfly valve 42, the butterfly valve 43, the exhaust pipe 41, and the opening and closing valve 44, thereby the chamber 10 The internal space SP is decompressed. The solvent component contained in the coating film 92 applied to the surface of the substrate 9 is vaporized in accordance with the pressure reduction of the internal space SP. Thereby, the pressure reduction treatment of the coating film 92 on the substrate 9 is started.

At the time of the pressure reduction treatment, since the rod heater is already operating in step S1, the substrate 9 is also subjected to heat treatment (step S4). That is, the substrate 9 is heated from the lower surface side by the rod heater in the internal space SP where the ambient temperature rises. By the heat treatment, the solvent component contained in the coating film 92 on the substrate 9 is heated to further promote vaporization of the solvent component. As described above, the vacuum drying apparatus 1 improves the drying efficiency of the coating film 92 by performing the pressure reduction and the drying under reduced pressure in the internal space SP (drying step).

When the exhaust pipe 41 is heated to the target pipe temperature, the pressure reduction process and the drying process are simultaneously performed, and when the drying of the coating film 92 is completed, the exhaust pump 45 is stopped, and the valve opening (not shown) is opened ( The open valve) thereby restores the internal space SP of the chamber 10 to atmospheric pressure. Then, the chamber elevating mechanism 12a raises the lid portion 12 of the chamber 10, and the hand of the transfer robot enters the inside of the chamber 10 to receive the substrate 9 on the substrate holding pin 21 and carry it out to the outside of the chamber 10 ( Step S5: Carry out the step). By the above, the vacuum drying treatment of one of the substrates 9 is completed. In addition, heating of the internal space SP by the substrate heating unit 30 and heating of the exhaust pipe 41 by the pipe heating unit 50 are continued.

As described above, in the vacuum drying apparatus 1 , while the exhaust pipe 41 is heated, the vacuum drying process is performed, so that the solvent component contained in the exhaust gas in the vacuum drying process can be prevented from being liquefied. Adhered to the exhaust pipe 41. As a result, the reduced-pressure drying process can be performed by the vacuum drying apparatus 1 in a short time. Further, each time the vacuum drying treatment is performed, the solvent component remaining on the exhaust pipe 41 can be suppressed, and the reduced-pressure drying treatment can be stably performed. In particular, even when a plurality of substrates 9 are continuously processed, each of the substrates 9 can be dried under reduced pressure at a fixed tact time.

It is to be noted that the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit and scope of the invention. For example, in the above-described embodiment, the entire exhaust pipe 41 is uniformly heated in the reduced-pressure drying process to be adjusted to the target pipe temperature. However, the pipe temperature may be different. This is because when the exhaust pipe 41 is extended, the temperature of the exhaust gas passing through each region in the region close to the chamber 10 and the region away from the chamber 10 in the exhaust pipe 41 are different. That is, the further away from the chamber 10, the lower the temperature of the exhaust gas in the exhaust pipe 41, and the more likely the liquefaction phenomenon occurs. Therefore, it is preferable to perform heating so that the temperature of the exhaust pipe 41 is higher as it goes away from the chamber 10.

Further, in the above-described embodiment, the present invention is applied to a vacuum drying apparatus 1 for drying a coating film 92 formed by coating a polyamic acid solution on the upper surface 91 of the substrate 9, and drying it under reduced pressure. The scope of application of the invention is not limited thereto, and may be applied to coating including a resist liquid, an interlayer insulating material, a low dielectric material, a ferroelectric material, a wiring material, an organic metal material, a metal paste, or the like. A device for drying a membrane under reduced pressure. Further, the present invention can also be applied to a vacuum drying apparatus which reduces the coating film formed on the lower surface of the substrate 9 or both surfaces of the substrate 9 under reduced pressure.

As described above, as described in the specific embodiment, the present invention may be configured such that the temperature of the exhaust pipe is adjusted to be higher than the dew point temperature of the exhaust gas containing the solvent component discharged through the exhaust pipe by the pipe temperature control unit. temperature. That is, in order to suppress liquefaction of the solvent component of the exhaust pipe, it is preferable to adopt the configuration as described above.

In addition, it is preferable to adjust the temperature of the exhaust pipe to a temperature lower than the internal space by the piping temperature control unit, thereby preventing the exhaust speed from decreasing.

In addition, it is preferable that the heating portion of the pipe is configured to be heated so that the temperature of the exhaust pipe is higher as it is farther away from the chamber, whereby the liquefaction of the solvent component can be effectively prevented even when the exhaust pipe is extended. It is thus preferred. [Industrial availability]

The present invention can be applied to all vacuum drying techniques for drying a coating film formed on a substrate by using a reduced pressure treatment and a heat treatment in combination.

1‧‧‧Decompression drying device
9‧‧‧Substrate
10‧‧‧ chamber
11‧‧‧Base section
12‧‧‧ 盖部
12a‧‧‧Case lift mechanism
13‧‧‧O-ring
20‧‧‧Substrate retention department
21‧‧‧Substrate retention pin
22‧‧‧Support members
22a‧‧‧ Pin lifting mechanism
30‧‧‧Substrate heating department
40‧‧‧Exhaust Department
41‧‧‧Exhaust piping
41a‧‧‧Pipe temperature sensor
42, 43‧‧‧ butterfly valve
44‧‧‧Opening valve
45‧‧‧Exhaust pump
50‧‧‧Pipe heating department
51‧‧‧Pipe heater
60‧‧‧Control Department (Pipe Temperature Control Department)
Upper surface of 91‧‧‧ (substrate)
92‧‧‧Coating film
111, 112‧‧ vents
411, 412‧‧‧ branch end
S1 ~ S5‧‧‧ steps
SP‧‧‧(room) interior space

Fig. 1 is a longitudinal cross-sectional view showing a configuration of an embodiment of a reduced-pressure drying apparatus according to the present invention. Fig. 2 is a block diagram showing the configuration of the reduced-pressure drying apparatus shown in Fig. 1; Fig. 3 is a graph showing the pressure reduction characteristics in the vacuum drying apparatus shown in Fig. 1; 4 is a graph showing an example of a vapor pressure curve of a solvent. Fig. 5 is a flow chart showing the operation of the vacuum drying apparatus shown in Fig. 1 .

1‧‧‧Decompression drying device

9‧‧‧Substrate

10‧‧‧ chamber

11‧‧‧Base section

12‧‧‧ 盖部

12a‧‧‧Case lift mechanism

13‧‧‧O-ring

20‧‧‧Substrate retention department

21‧‧‧Substrate retention pin

22‧‧‧Support members

22a‧‧‧ Pin lifting mechanism

30‧‧‧Substrate heating department

40‧‧‧Exhaust Department

41‧‧‧Exhaust piping

42, 43‧‧‧ butterfly valve

44‧‧‧Opening valve

45‧‧‧Exhaust pump

50‧‧‧Pipe heating department

51‧‧‧Pipe heater

Upper surface of 91‧‧‧ (substrate)

92‧‧‧Coating film

111, 112‧‧ vents

411, 412‧‧‧ branch end

SP‧‧‧(room) interior space

Claims (6)

A vacuum drying apparatus that decompresses an internal space by discharging an environmental gas in the internal space through an exhaust pipe connected to the chamber while accommodating the substrate in an internal space of the chamber The internal space is heated to vaporize a solvent component contained in the coating film on the substrate to dry the coating film, and the vacuum drying apparatus is characterized by comprising: a piping heating portion, The exhaust pipe is heated. The vacuum drying apparatus according to claim 1, further comprising: a piping temperature control unit that adjusts a temperature of the exhaust pipe by controlling the pipe heating unit. The decompression drying apparatus according to the second aspect of the invention, wherein the piping temperature control unit adjusts a temperature of the exhaust pipe to be higher than a discharge including the solvent component discharged through the exhaust pipe. The temperature of the dew point temperature of the gas. The reduced-pressure drying apparatus according to the second aspect of the invention, wherein the piping temperature control unit adjusts a temperature of the exhaust pipe to be lower than a temperature of the internal space. The vacuum drying apparatus according to any one of the first to fourth aspect, wherein the pipe heating unit is a method in which a temperature of the exhaust pipe is higher as it is farther from the chamber Heat up. A method of drying under reduced pressure, comprising: a housing step of accommodating a substrate on which a coating film is formed in an internal space of a chamber; and a drying step of discharging the internal space via an exhaust pipe connected to the chamber The internal space is depressurized by the ambient gas, and the internal space is heated, thereby vaporizing the solvent component contained in the coating film on the substrate to dry the coating film; The piping heating step is performed simultaneously with the drying step to heat the exhaust pipe.