KR100769638B1 - Reduced-pressure drying apparatus - Google Patents

Abstract

The present invention provides a reduced pressure drying apparatus that can optimize the solvent evaporation rate of the applied liquid according to the type of liquid in the drying process, and can perform the reduced pressure drying under a substantially uniform vapor pressure distribution of the solvent. Let's make it a task.

The vacuum drying apparatus 10 includes a chamber having a first chamber 1 and a second chamber 2 that mount and place the substrate W coated with the liquid L on the mounting table 11. 3) and the vacuum pump 6 as a pressure reduction means provided in the state which can pressure-reduce the 2nd chamber 2 is provided. Moreover, the communication port 19 as a communication part provided in the partition part 18 which partitions the 1st chamber 1 and the 2nd chamber 2, and the communication valve 8 which can open and close the communication port 19 are provided. do. Moreover, the control part which controls the drive of the vacuum pump 6 and the opening / closing of the communication valve 8 is provided. Moreover, the vacuum gauges 4 and 5 which detect the pressure of each of the 1st chamber 1 and the 2nd chamber 2 are provided. The volume of the 2nd chamber 2 is set larger than the volume of the 1st chamber 1.

Chamber, vacuum pump, vacuum gauge, partition wall, communication port

Description

REDUCED-PRESSURE DRYING APPARATUS}

1 is a schematic view showing the structure of a vacuum drying apparatus of Example 1. FIG.

Figure 2 is a block diagram showing the electrical or mechanical configuration of the vacuum drying apparatus of Example 1.

3 (a) to 3 (c) are graphs showing a reduced pressure drying profile of the reduced pressure drying device.

4 is a schematic view showing the structure of a vacuum drying apparatus of Example 2. FIG.

5 is a schematic view showing the structure of a vacuum drying apparatus of Example 3. FIG.

6 is a block diagram showing the electrical or mechanical configuration of the vacuum drying apparatus of Example 3. FIG.

7 is a schematic view showing the structure of a vacuum drying apparatus of Example 4. FIG.

8 is a block diagram showing the electrical or mechanical configuration of the vacuum drying apparatus of Example 4. FIG.

* Description of the symbols for the main parts of the drawings *

1, 31, 51, 81: 1st room 2, 32, 52, 82: 2nd room

3, 33, 53, 83: chamber

4, 5, 34, 35, 54, 55, 84, 85a, 85b, 85c: vacuum gauge as pressure gauge

6, 36, 56, 86: vacuum pump as a decompression means

8, 38: communicating valve

9, 39, 59, 89: N ₂ valve as an introduction valve

10, 30, 50, 80: pressure reduction drying apparatus 15, 45: rectification plate

15b, 45b: vent hole

19, 49: communication port as communication part

20, 70, 100: control unit 21, 71, 101: arithmetic unit

58, 88a, 88b, 88c: Conductance Valve as Communication Valve

65: motors 69, 99a, 99b, 99c as moving means: communication part

82a, 82b, 82c: actual L: liquid

W: substrate as work

This invention relates to the pressure reduction drying apparatus used when drying the workpiece | work to which the liquid body was apply | coated under reduced pressure, and forming a film on the surface of a workpiece | work.

When forming a film by apply | coating the liquid body containing a film formation material to the surface of wafer-like board | substrates, such as a semiconductor, the pressure reduction drying apparatus which evaporates and dries the solvent component contained in a liquid body under reduced pressure is used. As this pressure reduction drying apparatus, the pressure reduction drying apparatus which has arrange | positioned the rectification plate so that a board | substrate may be faced in the chamber which mounts and arrange | positions the board | substrate with which photoresist was apply | coated, and depressurizes, and the vent hole was formed in the edge part of a rectification plate is proposed (patent document One).

In the pressure reduction drying apparatus, the air flow in a predetermined direction toward the exhaust port is formed from the edge of the wafer-shaped substrate via the vent hole of the rectifying plate from the edge portion side of the wafer-like substrate. As a result, the velocity of the airflow flowing between the rectifying plate and the substrate becomes uniform in the substrate surface, so that the coating film is uniformly flattened in the substrate surface to form a coating film having a uniform film thickness on the substrate.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2002-313709

Thus, in the manufacturing process of many electronic devices including a semiconductor, the process of apply | coating the liquid body containing a functional material to workpiece | works, such as a wafer, and forming the coating film which consists of functional materials on the surface of a workpiece | work is employ | adopted.

However, in the drying process in which a liquid is dried to form a coating film, the coating film after formation is more flat, and it is very difficult to use the reduced pressure drying device to dry the film so that the film thickness distribution becomes uniform even within the surface of the workpiece. This is because a variety of liquids are used, and saturation vapor pressure and rheology characteristics (such as viscosity, elasticity, plasticity, thixotropy, etc.) change for various materials. This is because the liquid behavior such as the evaporation rate in the drying process also changes depending on the volume and surface area ratio of the solute and the solvent contained in the liquid.

Therefore, even if the airflow of the solvent evaporating from the liquid under reduced pressure using the conventional vacuum drying apparatus is installed and controlled so as to have a constant velocity in a predetermined direction, the flow of the liquid in the drying process (convection) ), The uniformity of the film thickness is lowered by the surface tension. Moreover, a difference arises in vapor concentration (or pressure) distribution in the center part and the edge part of a workpiece | work, As a result, there exists a subject that the in-plane distribution of the film thickness arises by the difference of a drying rate. Furthermore, there is also a problem that the versatility of carrying out the structural design of the optimum drying apparatus each time corresponding to various liquid materials and the shapes of the workpieces to be applied is reduced.

The present invention has been made in view of the above problems, in the drying process, it is possible to optimize the solvent evaporation rate of the applied liquid according to the type of liquid, so that drying under reduced pressure in a state in which the vapor pressure distribution of the solvent is approximately uniform It is an object to provide a vacuum drying apparatus that can be performed.

The pressure reduction drying apparatus of this invention accommodates the workpiece | work to which the liquid body containing a film formation material was apply | coated in a chamber, and is a pressure reduction drying apparatus which evaporates and dries the solvent of a liquid body under reduced pressure, and a chamber accommodates a workpiece in a substantially sealed state. At least a second chamber having a first possible chamber, a second chamber connected by the first chamber and the communicating section, and provided with at least a second chamber in a state capable of depressurizing the second chamber, a communication valve capable of opening and closing the communicating section, and a decompression means; And a control unit for controlling the open / close state of the communication unit by controlling the decompression state of the control unit.

The rheological properties of the liquid applied to the work differ depending on the kind of the liquid. For this reason, if the vapor pressure or evaporation rate changes rapidly due to the reduced pressure, depending on the type of the liquid, the behavior of the liquid in the drying process is affected, causing a film thickness variation after drying. In order to dry the film | membrane after drying and the film thickness nonuniformity on a workpiece surface is small, it is important to evaporate a solvent so that a liquid body may flow and a shape change may not occur in a drying process. According to this structure, a chamber is divided into the 1st chamber which accommodates a workpiece | work, and the 2nd chamber which can decompress | reduce by a decompression means, and a control part can drive a communication valve to make a 1st chamber sealed, or can communicate a 1st chamber and a 2nd chamber. have. Therefore, if the first chamber is sealed after the first chamber and the second chamber are reduced in pressure, the solvent evaporates in the first chamber, whereby a pressure difference can be generated between the first chamber and the second chamber. Thereby, the flow of a liquid can be suppressed by making the solvent evaporation rate of the apply | coated liquid body into the moderate speed corresponding to the pressure reduction state of a 1st chamber. If the solvent evaporates and the pressure of the first chamber increases and then communicates with the second chamber, the pressure difference can be used to diffuse the vapor of the solvent to the second chamber side. Then, when the vapor of the solvent diffused into the second chamber is discharged by the decompression means, the liquid can be dried. In addition, since sealing of the first chamber is not affected by the exhaust by the decompression means, the evaporation rate unevenness of the solvent due to the air flow of the exhaust can be reduced. That is, by setting the reduced pressure state of the 1st chamber according to the kind of liquid body, the solvent evaporation rate of the apply | coated liquid body can be optimized, and the reduced pressure drying which can perform pressure reduction drying in the state in which the vapor pressure distribution of a solvent is substantially uniform is carried out. A device can be provided. In addition, it is possible to more accurately set the decompression conditions according to the type of the liquid body, and it is possible to provide a decompression drying apparatus to which versatility is provided.

Further, there is further provided a pressure gauge capable of measuring at least the depressurization state of the first chamber, and the control unit drives the communication valve to communicate the first chamber and the second chamber, and drives the decompression means so that the detected pressure of the pressure gauge is at a predetermined operating pressure. After depressurizing the 1st chamber and the 2nd chamber until it is set, the communication valve is driven, the communication part is closed, the 1st chamber is sealed, and when a pressure gauge detects that the 1st chamber rose to the predetermined pressure, the communication valve is driven. And the first chamber and the second chamber are in communication with each other, and a control operation is performed in which the vapor of the solvent diffused in the first chamber and the second chamber is discharged by the decompression means.

According to this structure, a control part communicates a 1st chamber and a 2nd chamber, and closes a 1st chamber after depressurizing until the detection pressure of a pressure gauge becomes a predetermined | prescribed operating pressure. Therefore, the solvent can be evaporated from the liquid applied to the workpiece with the first chamber at a predetermined operating pressure without being affected by the airflow of the exhaust gas by the decompression means. When the pressure gauge detects that the first chamber has risen to a predetermined pressure, the first chamber and the second chamber communicate with each other, and the vapor of the solvent diffuses from the first chamber at the predetermined pressure to the second chamber in communication. . Then, a control operation is performed in which the vapor of the solvent diffused by the decompression means is discharged to dry the liquid at reduced pressure. Therefore, by sealing the 1st chamber at the predetermined | prescribed operating pressure, the solvent evaporation rate of the apply | coated liquid body can be made into the speed corresponding to a predetermined | prescribed operating pressure. Moreover, since it is not influenced by the exhaust by the decompression means, the evaporation rate unevenness of the solvent due to the air flow of the exhaust is reduced. In other words, the first chamber is set at a predetermined operating pressure according to the type of liquid, and the solvent evaporation rate of the applied liquid is optimized, and the vacuum drying can be carried out under reduced pressure in a state in which the vapor pressure distribution of the solvent is substantially uniform. A device can be provided.

The predetermined pressure is a pressure obtained by adding a predetermined operating pressure to a vapor pressure in which a predetermined amount of solvent evaporates in the sealed first chamber, and the control unit is a solvent diffused into the first chamber and the second chamber under a pressure equal to or higher than the predetermined pressure. It is characterized by discharging the steam by the decompression means.

According to this structure, the predetermined pressure is made into the pressure which added the predetermined | prescribed operating pressure to the vapor pressure at the time of fixed amount of solvent evaporating in the sealed 1st chamber, and a control part performs exhaust | emission under the pressure higher than predetermined pressure. Therefore, it is possible to suppress the evaporation of the solvent to a certain amount or more evaporated in the first chamber during the exhaust by the decompression means. Therefore, since it becomes possible to manage the quantity of the solvent which evaporates in the sealed 1st chamber, and since the ratio of the solute and solvent in a reduced pressure drying process can be estimated, when the quantity of the solvent to evaporate beforehand is set suitably, It is possible to provide a vacuum drying apparatus capable of performing vacuum drying under optimized conditions. In addition, the fixed amount of solvent in this case may be made into the whole quantity of the solvent contained according to the kind of liquid body, and may be made into the quantity which divided | segmented whole quantity suitably.

The predetermined operating pressure is set to a pressure at which the viscosity increases until just before the viscosity at which the solvent evaporates from the liquid and affects the membrane shape. It can also be called the pressure which added predetermined | prescribed operating pressure to the substantially saturated vapor pressure which evaporated.

According to this, the predetermined | prescribed operating pressure is set to the pressure which a viscosity increases until just before the viscosity which a solvent evaporates from a liquid and affects a film shape, and the solvent evaporated in the 1st chamber by which the predetermined pressure was sealed. The pressure is set to the saturated vapor pressure plus the predetermined operating pressure. Thus, when the solvent evaporates in the first chamber and reaches approximately saturated vapor pressure, the system of liquid and vaporized vapor approaches equilibrium with increasing viscosity to the viscosity that affects the membrane shape. Thus, the first chamber is kept sealed until the evaporation rate of the solvent becomes considerably slower than the initial evaporation. That is, it can dry under reduced pressure in the state which does not affect a film | membrane shape by the flow of a liquid body, without changing the evaporation rate abruptly. In addition, the vapor pressure distribution of the solvent on the workpiece surface can be made more uniform by approaching the equilibrium state. That is, the pressure reduction drying apparatus which is more flat in the film shape after drying, and can reduce in-plane film thickness nonuniformity can be provided.

In addition, the controller controls the second chamber in a non-communication state for a predetermined time until the vapor of the solvent diffused in the first chamber and the second chamber communicated by driving the communication valve through the pressure reducing means. It is preferable to depressurize by pressure reduction means to the pressure below pressure.

According to this configuration, the second chamber in non-communication state is reduced by a pressure reducing means to a pressure less than a predetermined operating pressure until the vapor of the solvent diffused in the first chamber and the second chamber communicated by the pressure reducing means. Since the pressure is reduced, the vapor of the solvent evaporated in the first chamber can be easily diffused and discharged to the lower side of the second chamber.

In addition, it is preferable that the control unit repeatedly executes a control operation from the operation of depressurizing the first chamber and the second chamber communicated by the decompression means to the operation of discharging vapor of the solvent diffused into the first chamber and the second chamber. .

The amount of the liquid applied to the work and the amount of the solvent contained therein vary depending on the shape (film thickness, area, density) of the film to be formed on the work. According to this, since a control part can repeatedly perform a control operation, it can provide the reduced pressure drying apparatus which can reliably dry under reduced pressure repeatedly and reliably in response to the quantity of the applied liquid or the quantity of the solvent. Can be. In addition, when repeating the control operation which performs pressure reduction drying, after diffusing the vapor of a solvent from a 1st chamber to a 2nd chamber, it is preferable to close the 1st chamber again, and to discharge the diffused steam by a decompression means. Do. According to this, by sealing a 1st chamber again, the fluctuation | variation of the vapor pressure of the solvent which remains in the vicinity of the surface of a liquid body can be suppressed, and the influence of the exhaust of a pressure reduction means on liquid behavior can be reduced.

The pressure gauge further includes a pressure gauge capable of measuring the depressurization state of at least the second chamber, and the control unit drives the communication valve to close the first chamber, and then drives the decompression unit so that the detected pressure of the pressure gauge becomes a predetermined operating pressure. After depressurizing the second chamber in a non-communication state until then, the communication valve was driven to open the communication section to communicate the first chamber and the second chamber, and the vapor of the solvent diffused in the first chamber and the second chamber was discharged by the decompression means. The control operation may be performed.

Depending on the type of liquid body, when the vapor pressure of the solvent is high, if the workpiece to which the liquid body is applied is sealed in the chamber and decompressed, a considerable amount of solvent will evaporate before reaching a predetermined operating pressure. It is very difficult to control the upper body flow. According to this structure, after sealing a 1st chamber, a control part drives a decompression means and pressure-reduces a 2nd chamber until the detection pressure of a pressure gauge becomes a predetermined operating pressure. Thereafter, the communication valve is driven to open the communication portion to communicate the first chamber and the second chamber. Therefore, the first chamber in which the work is sealed in a state where solvent evaporation does not occur at about atmospheric pressure can be brought into sudden reduction in pressure by communicating with a second chamber that has at least reached a predetermined operating pressure. In other words, it is possible to provide a reduced pressure drying apparatus capable of rapidly drying under reduced pressure by reducing the behavior of the liquid flow generated in the reduced pressure process.

The predetermined operating pressure is set to a value higher than the vapor pressure of the solvent of the liquid body. Evaporation of the solvent from the liquid under reduced pressure begins to evaporate from solvent molecules having a high kinetic energy even if the reduced pressure does not become a pressure corresponding to the vapor pressure of the solvent. According to this, since the predetermined operating pressure is set to a value higher than the vapor pressure of the solvent of the liquid, the solvent does not evaporate rapidly and does not droop, and the solvent evaporates while suppressing the flow of the liquid by Dolby. Can promote.

Moreover, it is preferable that the volume of the said 2nd chamber is set larger than the volume of the said 1st chamber. According to this, since the volume of a 2nd chamber is larger than the volume of a 1st chamber, when the 1st chamber and the 2nd chamber which pressure rose by the evaporation of a solvent communicate, the solvent evaporates from the liquid body of the workpiece accommodated in the 1st chamber. Vapor can be easily diffused to the second chamber side.

Further, at least the first chamber further has an introduction valve capable of introducing an inert gas from the outside, and the control unit drives the introduction valve to introduce the inert gas when discharging the vapor of the solvent diffused into the at least first chamber. It is done.

According to this structure, since a control part drives an inlet valve and introduces an inert gas, when discharging the vapor | steam of the solvent spread | diffused at least in a 1st chamber, it can discharge | emit the vapor | steam of a solvent quickly. In addition, when the first chamber is in communication with the second chamber, the pressure of the first chamber is lower than the predetermined operating pressure, and the fluctuation of the vapor pressure of the solvent remaining near the surface of the work can be reduced. That is, the pressure reduction drying apparatus which can perform pressure reduction drying in the state in which the vapor pressure distribution of a solvent is more uniform can be provided.

Moreover, it is preferable that the rectifying plate which rectifies a flow is provided in the 1st chamber, when the introduced inert gas flows from the workpiece side to the communication part direction.

According to this configuration, since the rectifying plate is provided in the first chamber in which the work is accommodated, when the solvent vapor is discharged by the inert gas, the flow direction of the inert gas is rectified in the direction toward the communication portion from the work side and uniformly. Can be discharged.

Moreover, it is preferable to further provide the variable means which changes the volume ratio of a said 1st chamber and a said 2nd chamber. According to this, even if the evaporation amount of a solvent differs according to the liquid body apply | coated to a workpiece | work, the volume ratio of a 1st chamber and a 2nd chamber is changed with a variable means corresponding to an evaporation amount, and a vapor | steam of a solvent is ensured on the 2nd chamber side. Can spread.

In addition, the chamber may have a partition wall partitioning the interior of the chamber into a first chamber and a second chamber, and the variable means may be referred to as a moving means for changing the volume ratio of the first chamber and the second chamber by moving the partition wall. In addition, the second chamber has a plurality of chambers having communication valves capable of communicating with each other, and the variable means includes a communication valve for communicating a plurality of chambers constituting the second chamber and a number of threads communicating with each other by driving the communication valve. It may also be referred to as a control unit for changing.

The embodiment of the present invention will be described by taking an example of a reduced pressure drying apparatus used in a process of forming an alignment film covering a pixel electrode of a pair of substrates constituting a liquid crystal display panel of a liquid crystal display device.

(Example 1)

1 is a schematic view showing the structure of a vacuum drying apparatus of Example 1. FIG. In detail, FIG. 1A is a schematic view showing the inside from the side of the apparatus, and FIG. 1B is a schematic view showing the inside from the upper surface of the apparatus. As shown in FIG. 1A, the pressure reduction drying apparatus 10 of the present embodiment includes a substrate W as a work on which a liquid body L containing an alignment film forming material as a film forming material is applied. ), And the solvent of the liquid L is evaporated under reduced pressure to dry.

The chamber 3 has a first chamber 1 on the upper side and a second chamber 2 on the lower side in the drawing, so that the volume of the second chamber 2 is larger than the volume of the first chamber 1. The partition wall part 18 which partitions the inside of the chamber 3 is provided. On the side of the first chamber 1 of the partition wall portion 18, a mounting table 11 on which the substrate W is mounted is disposed, and a rectifying plate 15 disposed so as to face a predetermined distance therefrom. The rectifying plate 15 is provided with a plurality of vent holes 15a through which gas is passed in a range corresponding to the region of the substrate W to be mounted.

A connection hole 17 is formed in the vicinity of the upper center of the first chamber 1, and one side of a pipe 14 capable of introducing nitrogen (N ₂ ) gas, which is an inert gas, is connected to the first chamber 1. . The other side of the pipe 14 is connected to an N ₂ gas supply source (not shown) via an N ₂ valve 9 as an inlet valve. Moreover, the vacuum gauge 4 as a pressure gauge which can measure the pressure reduction state in the 1st chamber 1 is provided in the side wall surface of the 1st chamber 1. The vacuum gauge 4 is electrically connected to the control part 20 (refer FIG. 2) mentioned later, and outputs the pressure value as a detection result.

The connection hole 16 is formed in the center vicinity of the lower part (bottom surface) of the 2nd chamber 2, and one side of the piping 13 is connected. The other side of the pipe 13 is connected to the vacuum pump 6 as a pressure reduction means capable of decompressing the second chamber 2 via the vacuum valve 7. The vacuum pump 6 uses a dry pump and a turbo molecular pump, for example. Moreover, these pumps can also be used in combination so that setting of the operating pressure which makes a target pressure reduction state possible. On the side wall surface of the 2nd chamber 2, the vacuum gauge 5 as a pressure gauge which can measure the pressure reduction state in the 2nd chamber 2 is provided. Similarly, the vacuum gauge 5 and the vacuum pump 6 are electrically connected to a control unit 20 (see FIG. 2), which will be described later. The control unit 20 detects an output (pressure value) of the vacuum gauge 5 to detect a vacuum pump ( It is possible to control the exhaust speed of 6).

As shown in FIGS. 1A and 1B, the partition wall portion 18 has a communication port 19 as a communication portion where the first chamber 1 and the second chamber 2 of the chamber 3 communicate with each other. Four places are provided along the edge of the mounting mounting table 11. Four communication valves 8 in which the rotation shaft 8a is connected to the four motors 12 attached to the outer wall of the chamber 3 are respectively provided in the part in which the four communication ports 19 open. As the communication valve 8 drives the motor 12 and the rotation shaft 8a rotates, the valve 8b attached to the rotation shaft 8a opens and closes the communication port 19. When the communication valve 8 closes the communication port 19, the first chamber 1 and the second chamber 2 are sealed to each other. The four motors 12 are electrically connected to the control unit 20 (see FIG. 2), respectively, and the control unit 20 controls the open / closed state of the communication valve 8 by independently driving the four motors 12, respectively. do.

The pressure reduction drying apparatus 10 opens the communication valve 8 and drives the vacuum pump 6 in the state which closed the door (not shown) and sealed the inside of the chamber 3, and operates the 1st chamber ( It is possible to depressurize 1) and the 2nd chamber 2. In addition, when the communication valve 8 is closed to close the communication port 19 and the vacuum pump 6 is driven, only the second chamber 2 can be reduced in pressure.

2 is a block diagram showing the electrical or mechanical configuration of the vacuum drying apparatus. As shown in FIG. 2, the reduced pressure drying device 10 includes a calculation unit 21 having a CPU, a timer 22 for measuring time, and a storage unit 23 in which data of reduced pressure drying conditions such as a reduced pressure drying profile is stored. It has the control part 20 provided with. The two vacuum gauges 4 and 5 are electrically connected to the control part 20, and the decompression state of each of the 1st chamber 1 and the 2nd chamber 2 can be detected. In addition, the vacuum pump 6 is electrically connected, and driving, exhaust speed, and the like are controlled. The four motors 12 are electrically connected to control the driving of the motor 12, thereby controlling the open / closed state of the communication valve 8. Vacuum valve 7 and the N ₂ valve 9, and both the E (電磁) valves are used, these are also electrically connected to the control unit 20 is controlled to open and close. In addition, an input unit 24 and a display unit 25 having a drive device or the like of a recording medium capable of passing data between a keyboard and a recording medium are electrically connected. From the input part 24, pressure reduction drying conditions, such as a pressure reduction drying profile, can be input and memorize | stored in the memory | storage part 23. FIG. The display unit 25 displays the various input data and the pressure values of the first chamber 1 and the second chamber 2 detected by the vacuum gauges 4 and 5 and the operating state of the reduced pressure drying device 10. For example, the ON-OFF of an apparatus, opening and closing of various valves, the elapsed time corresponding to the pressure reduction drying step which the timer measured, etc. can be displayed. The calculating part 21 can calculate the evaporation amount of a solvent etc. based on the data contained in the pressure reduction drying profile etc. which were memorize | stored in the memory | storage part 23, and the output (pressure value) of the vacuum systems 4 and 5. In addition, the set pressure of the decompression drying operation as the control operation included in the decompression drying profile or the like can be read to execute the decompression drying operation.

Next, the operation of the vacuum drying apparatus 10 will be described based on the vacuum drying profile. 3 is a graph showing a reduced pressure drying profile of the reduced pressure drying apparatus. In detail, (a) of FIG. 3 is a graph which shows the evaporation amount control type, FIG. 3 (b) is a shape control type, and FIG. In addition, the value of the pressure P of a vertical axis | shaft is a logarithmic value.

Before demonstrating each vacuum drying profile, the liquid L containing an oriented film formation material is demonstrated. The liquid crystal display panel of a liquid crystal display device has a pair of board | substrates which have a pixel, and the liquid crystal as an electro-optic material interposed between a pair of board | substrates. The liquid crystal molecules constituting the liquid crystal have an electric moment along the direction of the molecules. In the so-called field effect type liquid crystal display panel, the light incident on the liquid crystal display panel (polarization) is controlled and displayed by directing the arrangement direction of the liquid crystal molecules when the electric field is not applied between opposing pixels. Can be done.

In this case, the alignment film which consists of organic thin films, such as polyimide, is formed in the surface of the board | substrate facing the liquid crystal side. Then, by rubbing (rubbing) the surface of the alignment film in a predetermined direction, fine irregularities are formed on the surface of the film, and when the electric field is not applied, the liquid crystal molecules are controlled to be aligned in a predetermined direction along the irregularities. . In the present Example, the liquid L in which the polyimide resin as an oriented film formation material melt | dissolved in the solvent is used. The solvent is obtained by mixing a plurality of organic solvents in a predetermined ratio, and for example, γ-butyrolactone, ethylene glycol monobutyl ether, and the like are used. Therefore, the liquid L is a multi-component liquid, and the physical properties such as boiling point and vapor pressure differ depending on the type of the organic solvent. The boiling point of gamma -butyrolactone is 204 占 폚 and the vapor pressure (20 占 폚) is 200 kPa. Moreover, the boiling point of ethylene glycol monobutyl ether is 170 degreeC and vapor pressure (20 degreeC) is 80 kPa.

When the substrate W coated with the liquid L is dried by evaporation of a solvent under reduced pressure to form an alignment film, when the surface of the alignment film after drying is not flat and the film thickness is different, a pair of substrates are used. The so-called gap of the thickness of the liquid crystal layer inserted into the film is nonuniform, resulting in color unevenness or orientation unevenness. In addition, since the polyimide resin itself is an insulating material and an electric capacitance component is formed on the surface of the substrate, when the film thickness is different, the capacitance component is changed, and the driving voltage applied to the liquid crystal layer is fluctuated, resulting in uneven display such as crosstalk. It becomes Therefore, it is preferable to dry so that the surface of the oriented film after drying may be flat and become a substantially constant film thickness. Therefore, since the rheological properties of the liquid L described above change according to the type of solute and solvent component, the blending ratio of each component, and the like, a reduced pressure drying profile corresponding to this is required. There is also a need for a pressure reduction drying apparatus that can cope with reduced pressure drying profiles of different conditions. Hereinafter, the operation of the vacuum drying apparatus 10 according to the vacuum drying profile will be described.

(Evaporation control type vacuum drying profile)

As shown in Fig. 3A, in the evaporation control type pressure-sensitive drying profile, the substrate W on which the liquid body L is coated is placed on the mounting table 11 of the first chamber 1, and the door is placed. It is closed and accommodated in the chamber 3. The control unit 20 first confirms that the N ₂ valve 9 is closed, and if closed, drives the motor 12 to open the four communication valves 8, and the first communication port 19 opens the first communication valves 19. Let the yarn 1 and the 2nd yarn 2 communicate.

Next, the vacuum valve 7 is opened to drive the vacuum pump 6 to start depressurization (time t ₀ ). First by the pressure P ₂ of the chamber 1, the pressure P ₁ and the second chamber (2) of the driving motor 12 at a time t ₁ at the predetermined operating pressure Ps closing the four communication valve (8) do. Thereby, the communication port 19 is closed and the 1st chamber 1 in which the board | substrate W was accommodated is sealed. In addition, the control unit 20 closes the vacuum valve 7 when the second chamber 2 is depressurized to a target pressure lower than the operating pressure Ps. The pressure P ₁ of the sealed 1st chamber 1 rises from operation pressure Ps, as shown by the dashed line of a graph, by the evaporation of the solvent of the liquid L. As shown in FIG. When the value of the pressure P ₁ is measured by the vacuum gauge 4, the pressure difference ΔP with the operating pressure Ps is obtained. Since the pressure difference ΔP depends on the amount of evaporation of the solvent (the slanted portion in the drawing), assuming that the solvent vapor evaporated under a constant temperature is an ideal gas, the amount of evaporation is applied to the gas state equation (PV = nRT). (Molecular weight) can be obtained. Since the amount of the liquid applied to the substrate W and the content rate of the solvent are known, the amount of evaporation of the solvent necessary for drying the applied liquid is determined by calculation. Therefore, when ΔP corresponding to a predetermined amount of solvent evaporation amount is set in advance, how much solvent is evaporated from the liquid L in the sealed first chamber 1 by at least one vacuum drying operation, It is possible to control the evaporation amount and dry under reduced pressure. In addition, although the predetermined amount of the solvent in this case made it the fixed amount which divided the whole quantity of the solvent contained in the liquid L by the number of reduced pressures, it can also change suitably in the repeating step of reduced pressure drying.

A calculation method for obtaining this amount of evaporation is input in advance from the input unit 24 as a program and stored in the storage unit 23. Computing unit 21 displays the amount of evaporation of the run the program, in conjunction with the pressure P ₁ transition (推移) of (連動) and the solvent stored in the storage unit 23 to the display unit 25.

Next, when the pressure P ₁ (or the pressure difference ΔP) reaches a predetermined value, that is, at time t ₂ when the vapor pressure evaporated in the first chamber 1 in which a certain amount of the solvent is sealed reaches the predetermined value, the controller is controlled. 20 drives the motor 12 to open the communication valve 8. At the same time, the N ₂ valve 9 is opened to introduce the N ₂ gas into the first chamber 1. The introduced N ₂ gas passes through the vent hole 15a formed in the rectifying plate 15 and flows from the top of the substrate W toward the communication port 19. Therefore, the vapor of the solvent evaporated from the liquid L is directed to the second chamber 2 side along the air flow of the N ₂ gas. At the same time, the control unit 20 opens the vacuum valve 7 to drive the vacuum pump 6 to perform exhaust. At this time, in response to the flow rate of N ₂ gas is controlled so as to decrease the pumping speed of the vacuum pump (6). In a state where the first chamber 1 and the second chamber 2 are in communication with each other, the N ₂ gas is introduced to thereby release the depressurized state of the first chamber 1 and the second chamber 2 to allow the interior of the chamber 3 to be released. Since the pressure rises and becomes higher than the predetermined pressure Ps + ΔP, the solvent evaporation of the liquid L is suppressed.

In addition, N ₂ gas as an inert gas may not be introduced as a method of discharging the vapor of the solvent. In the chamber 3 of the present embodiment, the volume of the second chamber 2 is set to be larger than that of the first chamber 1. Since the solvent evaporates from the liquid L in the sealed first chamber 1 and the pressure P ₁ becomes higher than the pressure P ₂ of the second chamber 2, the communication valve 8 is opened to open the first chamber. As long as the pressure P ₁ does not become lower than the operating pressure Ps when the chamber 1 and the second chamber 2 communicate with each other, the vapor of the evaporated solvent is diffused to the second chamber 2 with a large volume and small pressure. Can be discharged. Further, when the vapor of the solvent diffuses to the second chamber 2 side and the pressure P ₁ = pressure P ₂ , the first chamber 1 may be sealed and then exhausted. By doing in this way, the influence of the exhaust by the vacuum pump 6 can be made small, the solvent evaporation of the liquid L can be suppressed, and a uniform vapor pressure can be maintained.

Next, at the time t ₃ when the pressure in the chamber 3 rises to approximately atmospheric pressure, the control unit 20 closes the N ₂ valve 9. Then, the evacuation speed of the vacuum pump 6 is increased again, and the pressure inside the chamber 3 in which the first chamber 1 and the second chamber 2 communicate is reduced to a predetermined operating pressure Ps. Subsequently, the same operation as described above is performed. At the time t ₄ at which the operating pressure Ps is reached, the communication valve 8 is closed to seal the first chamber 1, and the pressure P ₁ is applied to a predetermined pressure Ps + ΔP. introducing the N ₂ gas at a reaching time t ₅ is carried out under reduced pressure drying operation to discharge the vapor of the solvent evaporated. Therefore, the control unit 20 by one cycle the pressure drying operation between the time t ₀ to time t _3, is carried out repeatedly until the solvent evaporates the liquid material (L) ends. When the solvent evaporates, the time until the pressure P ₁ of the sealed first chamber ₁ reaches a predetermined pressure Ps + ΔP becomes long. Therefore, it is possible to confirm the end time of drying.

Further, the longer the time until the pressure P ₁ of the sealed first chamber ₁ reaches the predetermined pressure Ps + ΔP can be considered that the evaporation rate of the solvent is lowered. In order to evaporate the solvent, the value of the operating pressure Ps may be changed in the course of a repeated drying operation under reduced pressure. For example, in the pressure-reducing drying operation performed repeatedly, when the first chamber 1 is sealed in a state in which the operating pressure Ps is lowered than the previous time or in a stepwise manner, the evaporation rate of the solvent can be suppressed from being lowered. That is, it becomes possible to accelerate | evaporate evaporation by making it substantially constant speed, or speed up evaporation rate. Alternatively, when the first chamber 1 is sealed in a state in which the operating pressure Ps is raised from the previous time or in stages, the later evaporation rate can be lowered as compared with the evaporation rate in the previous decompression drying operation. In other words, it is possible to promote the evaporation by controlling the evaporation rate. Thus, for example, if the accumulated evaporation amount N of the solvent calculated by the calculation unit 21 is 90% or more and less than 95% of the solvent amount M, the operating pressure Ps is lowered than before, so as to be 95% or more early. You may change and set a vacuum drying profile so that it may carry out.

In addition, the setting method of (DELTA) P value in a vacuum drying operation is as follows. The calculating part 21 can calculate the molecular weight of the solvent evaporated from the value of (DELTA) P. By calculating the molecular weight of the evaporated solvent, it is possible to calculate the molecular weight of the solvent remaining in the liquid (L), thereby analyzing how the ratio of the solute and the solvent of the liquid (L) is changed by reduced pressure drying. Can be. The rheological properties of the liquid L described above also vary depending on the ratio of solute and solvent. Therefore, in order to suppress the change in the shape of the liquid L in the drying process as much as possible, drying is carried out beforehand by changing the value of ΔP and drying under reduced pressure. It is possible to set a predetermined value of ΔP in which the cross-sectional shape is flat and the in-plane film thickness nonuniformity is small in accordance with the cycle of the decompression drying operation.

Next, the predetermined operating pressure Ps will be described. Even when the components of the solvent are single, the liquid L under reduced pressure begins to evaporate the solvent even if the reduced pressure does not reach the vapor pressure of the solvent (20 degrees). In particular, in the case of the multi-liquid liquid L as in the present embodiment, it is expected that the reduced pressure value at which evaporation of the solvent starts varies depending on the type and mixing ratio of the organic solvent. In the multi-liquid liquid L, as a method of investigating a change in the depressurization value or the amount of evaporation at which evaporation starts, for example, a measuring device (for example, an electronic balance) capable of measuring the mass of the liquid L is used. It installs in the chamber 3, and measures the liquid L of a suitable quantity. When the vacuum pump 6 is driven to depressurize the inside of the chamber 3 at a substantially constant speed, the relationship between the pressure P detected by the vacuum gauge 5 and the mass of the liquid L detected by the metering device is elucidated. can do. In the vicinity of the vapor pressure of the solvent, the pressure P may rapidly evaporate and rush. If it is Dolby, the shape of the liquid L will be largely disturbed, and the film | membrane of the cross-sectional shape after drying cannot be obtained. In addition, since dolby arises at the unspecified place of the surface of the board | substrate W to which the liquid body L was apply | coated, the film thickness in surface also differs. In order to avoid such a drawback, in this embodiment, setting of the operating pressure Ps which makes the 1st chamber 1 and the 2nd chamber 2 into a predetermined pressure reduction state is a value higher than the vapor pressure of a solvent, and evaporation of a solvent is carried out. It is slightly lower than the starting value.

As described above, the reduced pressure drying device 10 communicates the first chamber 1 and the second chamber ₂ at a time t ₂ at a predetermined pressure (Ps + ΔP) with respect to the operating pressure Ps. Since the decompression drying operation for discharging the steam is repeated, it is possible to control the amount of vapor and the evaporation rate corresponding to the pressure difference ΔP to perform the reduced pressure drying of the liquid body L.

(Shape controlled pressure reduction drying profile)

As shown in FIG.3 (b), in the shape-control type pressure reduction drying profile, the board | substrate W by which the liquid body L was apply | coated was mounted in the mounting base 11 of the 1st chamber 1, and a door is mounted. It is closed and accommodated in the substantially closed state in the chamber 3. The control unit 20 checks whether the N ₂ valve 9 is closed in the same manner as the above-described profile, and if it is closed, drives the motor 12 to open the four communication valves 8, and the communication port 19. By this, the first chamber 1 and the second chamber 2 are brought into communication with each other.

Next, the vacuum valve 7 is opened to drive the vacuum pump 6 to start depressurization (time t ₀ ). First by the pressure P ₂ of the chamber 1, the pressure P ₁ and the second chamber (2) of the driving motor 12 at a time t ₁ at the predetermined operating pressure Ps closing the four communication valve (8) do. Thereby, the communication port 19 is closed and the 1st chamber 1 in which the board | substrate W was accommodated is sealed. In addition, the control unit 20 closes the vacuum valve 7 when the second chamber 2 is depressurized to a target pressure lower than the operating pressure Ps. In this case, the predetermined operating pressure Ps is set to a value at which the liquid L increases in viscosity from the liquid L to just before the viscosity at which most solvents evaporate and affect the membrane shape.

Then, the pressure P ₁ of the sealed first chamber ₁ is left to time t ₂ when the predetermined pressure reaches the predetermined pressure. In this case, the predetermined pressure is set to the pressure obtained by adding the operating pressure Ps to the saturated vapor pressure Psa of the solvent of the sealed first chamber 1. The saturated vapor pressure Psa of the solvent can be obtained by calculation because the volume of the first chamber 1 is known. As a result, the liquid L is dried only by diffusion of steam until the saturated vapor pressure is reached, so that a considerably slower drying situation is given. Moreover, the vapor | steam of a solvent gradually fills in the sealed 1st chamber 1, and it is saturated, and the vapor pressure distribution in the surface of the board | substrate W is balanced, and it is a so-called equilibrium state. Therefore, the viscosity of the liquid L increases, the shape is substantially fixed, and in-plane uniformity can be brought into a good state. In this case, the pressure P ₁ may not be strictly the value of the operating pressure Ps + saturated vapor pressure Psa. If it is about saturated vapor pressure, it is judged that it is in an equilibrium state. It is also possible to compare ΔP and saturated vapor pressure Psa.

Next, the control unit 20 drives the motor 12 to open the communication valve 8. At the same time, the N ₂ valve 9 is opened to introduce the N ₂ gas into the first chamber 1. By the introduction of the N ₂ gas, the solvent vapor (evaporation amount corresponds to an oblique portion in the drawing) is discharged. Then, the exhaust speed of the vacuum pump 6 is made faster so as to correspond to the flow rate of the N ₂ gas and to extract the solvent remaining in the liquid L at a short time, and positive exhaust gas is performed. Since the liquid L has a substantially fixed shape, the liquid L can be dried under reduced pressure without affecting the shape even when such positive exhaust is performed.

After the positive evacuation is continued to time t ₃ , the vacuum pump 6 is stopped, external air is introduced, and the inside of the chamber 3 is returned to approximately atmospheric pressure to terminate the reduced pressure drying operation (time t ₄ ). Although it is preferable that pressure reduction drying is complete | finished by one pressure reduction drying operation, the quantity of the liquid body L apply | coated to the board | substrate W also depends on the area to be apply | coated. Therefore, in order to more reliably reduced pressure drying, it may be carried out under reduced pressure drying operation of one cycle of the operation from time t ₀ to time t ₄ repeatedly.

(Quick drying pressure reduction drying profile)

As shown in FIG.3 (c), in the quick-drying pressure reduction drying profile, the board | substrate W by which the liquid body L was apply | coated was mounted in the mounting base 11 of the 1st chamber 1, and the door Is housed in a substantially closed state in the chamber 3. The control unit 20 first checks whether the N ₂ valve 9 is closed, and if it is closed, drives the motor 12 to close the four communication valves 8, and the first chamber 1 and the second chamber. (2) We assume state not to communicate.

Next, the vacuum valve 7 is opened to drive the vacuum pump 6 to start depressurization (time t ₀ ). At the time t ₁ when the pressure P ₂ of the second chamber ₂ reaches the predetermined operating pressure Ps, the motor 12 is driven to open the four communication valves 8. As a result, the sealed first chamber 1 communicates with the second chamber 2 under reduced pressure. The pressure P ₁ of the first chamber 1 rapidly depressurizes toward the pressure P ₂ of the second chamber 2 from the state of substantially atmospheric pressure. In the meantime, the vacuum pump 6 is continuously driven, and the vapor | steam (the amount of vapor is equivalent to the diagonal part in a figure) of the solvent which evaporates from the liquid L is discharged | emitted. The predetermined operating pressure Ps in this case is set to be higher than the vapor pressure of the solvent of the liquid L. Therefore, it is set to the value which is hard to generate | occur | produce the dolby by sudden pressure reduction.

This rapid drying pressure-sensitive drying profile is a relatively high vapor pressure of the solvent compared to the case of the liquid (L) to which the other pressure-drying profile is applied, the considerable solvent is evaporated during the depressurization process until reaching the operating pressure Ps Is used in the case. Since the liquid L in the first chamber 1 is placed under a reduced pressure lowered to a predetermined operating pressure Ps at once, the solvent is rapidly evaporated to obtain a ratio of the solute and the solvent in which the shape of the liquid L is stabilized. It is possible to fix the shape at once.

As described above, the reduced pressure drying device 10 is a vapor amount controlled type for controlling the vapor amount or the evaporation rate of the solvent shown in FIG. 3A to perform drying of the liquid L, and the liquid body shown in FIG. It is possible to cope with each of the reduced pressure drying profiles of the shape control type to be dried after stabilizing the shape of L) and the quick drying type shown in Fig. 3C. Moreover, it is also possible to perform pressure reduction drying which combined these pressure reduction drying profiles.

The effect of Example 1 is as follows.

(1) The vacuum drying apparatus 10 includes a chamber 3 having a first chamber 1 and a second chamber 2 for receiving a substrate W on which the liquid body L to be dried under reduced pressure is coated; It is provided with the vacuum pump 6 which can depressurize at least the 2nd chamber 2, and the communication valve 8 which opens and closes the communication port 19 which connects the 1st chamber 1 and the 2nd chamber 2. As shown in FIG. Moreover, the control part 20 which controls the drive of the vacuum pump 6, and the opening / closing of the communication valve 8 is provided. Accordingly, the first chamber 1 and the second chamber 2 communicate with each other to drive the vacuum pump 6 to depressurize to a predetermined operating pressure Ps, and the communication valve 8 is closed to close the first chamber 1. Of the first chamber 1 to evaporate the solvent from the liquid L until the pressure P ₁ of the first chamber ₁ becomes a predetermined pressure, and then the communication valve 8 is opened to discharge the steam to dry, thereby reducing the amount of vapor. Drying profiles can be run. According to this, the solvent which evaporates while reducing the influence of the airflow by the exhaust of the vacuum pump 6 compared with the case where the pressure reduction drying of the liquid L is carried out under the reduced pressure which exhausts continuously by a pressure reduction means. The reduced pressure and evaporation rate can be controlled to dry under reduced pressure. In addition, after evaporating the solvent from the liquid L until the pressure P ₁ of the sealed first chamber ₁ becomes the operating pressure Ps + saturated vapor pressure Psa, the communication valve 8 is opened to discharge steam to dry. The shape controlled pressure reduction drying profile can be implemented. According to this, the solvent can be gradually evaporated until reaching the operating pressure Ps at which the viscosity of the liquid L is increased to make it less likely to change the shape, and then the saturated vapor pressure is reached. Then, after the shape of the liquid L is fixed, the first chamber 1 and the second chamber 2 communicate with each other to be actively evacuated, and the remaining solvent can be evaporated and dried. Moreover, while the communication valve 8 is closed and the 1st chamber 1 is closed, the 2nd chamber 2 is decompressed by the vacuum pump 6 to predetermined operation pressure Ps, and the communication valve 8 By opening the first chamber 1 and the second chamber 2 in communication with each other, it is possible to execute a rapid drying pressure-sensitive drying profile for drying the liquid L under reduced pressure at a time. That is, the pressure reduction drying apparatus 10 which has the versatility which can respond to the various pressure reduction drying profiles suitable for the rheological characteristic changed according to the solute of the liquid L, the kind of solvent, the compounding state, etc. can be provided.

(2) In the reduced-pressure drying apparatus 10, since the operating pressure Ps is set to a value higher than the vapor pressure of the solvent, the evaporation rate is significantly faster or the evaporation suddenly evaporates to reduce the phenomenon of liquid and liquid. It can be dried under reduced pressure so as not to affect the shape of (L).

(3) In the reduced pressure drying apparatus 10, since the control part 20 can repeatedly perform the reduced pressure drying operation as a control operation, it repeats a reduced pressure drying operation according to the application amount of the liquid L more reliably. It can be dried under reduced pressure.

(4) In the vacuum drying apparatus 10, since the volume of the 2nd chamber 2 is set to be larger than the volume of the 1st chamber 1, the 1st chamber 1 in which the pressure rose by the evaporation of the solvent 1 By communicating with the 2nd chamber 2, the vapor in the inside) can be spread | diffused to the 2nd chamber 2 side, and can be discharged | emitted by the vacuum pump 6.

(5) The pressure reduction drying apparatus 10 has an N ₂ valve 9 as an introduction valve capable of introducing N ₂ gas as an inert gas from the outside into the first chamber 1, and the control unit 20 includes a first chamber ( When the vapor of the solvent of 1) is discharged, the N ₂ valve 9 is driven to introduce N ₂ gas. Therefore, the vapor can be discharged quickly and the N ₂ gas is introduced to suppress the evaporation of the solvent remaining in the liquid L and to maintain the vapor pressure distribution on the surface of the substrate W in a more uniform state. Can be. That is, the in-plane film thickness nonuniformity after pressure reduction drying can be made smaller. Further, if the vapor pressure at which a certain amount of solvent evaporates in the sealed first chamber 1 is ΔP, N ₂ gas is introduced at the time of discharging the vapor of the solvent, so that evaporation of the solvent is suppressed. The evaporation amount can be controlled and dried under reduced pressure.

(6) mounted between in the reduced pressure drying apparatus 10, the first chamber (1), the mounting arrangement for the arrangement with a substrate (W) (11) with N ₂ the connection hole 17 that is a gas is introduced batch A rectifying plate 15 having a plurality of vent holes 15a is provided to face the table 11. Accordingly, the introduced N ₂ gas is rectified in the rectifying plate 15, and discharges vapor of a solvent evaporating from the liquid L applied on the substrate W along a predetermined air flow toward the communication port 19. You can. Therefore, the film thickness nonuniformity after drying by the exhaust nonuniformity of steam can be reduced. In addition, the 1st chamber 1 is provided above the 2nd chamber 2, and the mounting base 11 is arrange | positioned at the 1st chamber 1 side of the partition part 18. As shown in FIG. Therefore, when N ₂ gas is introduced from above the first chamber 1, airflow flows to press the substrate W downward. Thus, the substrate (W) by introduction of N ₂ gas is reduced to be a defect portion (浮上).

(Example 2)

4 is a schematic view showing the structure of a vacuum drying apparatus of Example 2. FIG. In detail, FIG. 4A is a schematic view showing the inside from the side of the apparatus, and FIG. 4B is a schematic view showing the inside from the upper surface of the apparatus.

As shown in FIG. 4A, the pressure reduction drying apparatus 30 of the present embodiment includes a first chamber 31 and a first chamber 31 which accommodate the substrate W on which the liquid body L is applied. The chamber 33 which has the 2nd chamber 32 provided so that the space | surrounding may be provided, and the vacuum pump 36 provided in the state which can depressurize the 2nd chamber 32 is provided.

The first chamber 31 is partitioned in the chamber 33 by partition walls 48 provided in a box shape on the inner bottom surface of the chamber 33. On the bottom of the first chamber 31, a mounting table 41 on which the substrate W is mounted is placed. In addition, a communication port 49 serving as an open communication portion 49 corresponding to the size of the substrate W is provided in the upper surface portion of the partition wall portion 48 facing the mounting table 41, and the first chamber 31 is provided. It communicates with the 2nd chamber 32 which surrounds. A plurality of communication valves 38 are attached in parallel in a state capable of opening and closing the communication ports 49. The post which stands up on the mounting placement table 41 side from the edge of the communication opening 49 so as to face the mounting placement table 41 at a predetermined distance between the communication opening 49 and the mounting placement table 41. (V) A rectifying plate 45 supported by 45a is provided. In the rectifying plate 45, a plurality of vent holes 45b through which gas is passed are provided in a range corresponding to the region of the substrate W to be mounted on the mounting table 41. Side wall of the box-shaped partition wall portion 48, there is one side of the connection hole 47 is formed, and the inert gas of nitrogen in the first chamber (31) (N ₂₎ as possible the gas introduction pipe 44 is connected. The other side of the pipe 44 is connected to an N ₂ gas supply source (not shown) via an N ₂ valve 39 as an inlet valve. Moreover, the vacuum gauge 34 as a pressure gauge which can measure the pressure-reduced state in the 1st chamber 31 is provided in the other side wall surface of the 1st chamber 31.

The connection hole 46 is formed in the side wall surface of the 2nd chamber 32, and one side of the piping 43 is connected. The other side of the pipe 43 is connected to the vacuum pump 36 via the vacuum valve 37. Moreover, the vacuum gauge 35 as a pressure gauge which can measure the pressure reduction state in the 2nd chamber 32 is provided in the other side wall surface of the 2nd chamber 32.

As shown in FIGS. 4A and 4B, the seven communication valves 38 communicate with each other by the communication port 49 by rotating the valves 38b attached to the rotation shaft 38a at approximately horizontal positions. To close the first chamber 31 in a sealed state. Each rotating shaft 38a is attached to the motor 42 provided in the outer wall part of the chamber 33, respectively.

The pressure reduction drying apparatus 30 of Example 2 has the structure similar to the basic structure of the pressure reduction drying apparatus 10 of Example 1. As shown in FIG. Therefore, the volume of the 2nd chamber 32 is set so that it may be larger than the volume of the sealed 1st chamber 31. However, when discharging the vapor of the solvent evaporating from the liquid L, N ₂ gas is introduced from the side of the substrate W. As shown in FIG. Then, N ₂ gas containing steam is rectified by passing through the vent hole 45b of the rectifying plate 45, and flows into the second chamber 32 through the seven communication valves 38 that are opened, thereby connecting. The point of the structure discharged by the vacuum pump 36 through the hole 46 differs. That is, it is the structure which can discharge the vapor | steam of the solvent evaporated from the liquid L to the upper direction of the board | substrate W. As shown in FIG.

Therefore, the electrical or mechanical configuration of the vacuum drying apparatus 30 is the same as that of the vacuum drying apparatus 10 of the first embodiment shown in the block diagram of FIG. 2, and only the symbols of the corresponding respective components are different. For this reason, the pressure reduction drying apparatus 30 can perform the pressure reduction drying operation corresponding to each pressure reduction drying profile shown to Fig.3 (a)-(c).

The effect of the said Example 2 has the same effect as the effect (1)-(5) of the said Example 1, and has the following effects.

(1) In the vacuum drying apparatus 30 of the said Example 2, the communication port 49 which connects the 1st chamber 31 and the 2nd chamber 32 is the board | substrate W to which the liquid L was apply | coated (W). ) Is provided on the upper surface portion of the partition wall part 48 so as to face the mounting mounting table 41 on which the mounting table is disposed. Therefore, the reduced pressure drying apparatus 30 which can diffuse | evaporate and discharge the vapor | steam of the solvent which evaporates from the substantially whole surface of the area | region to which the liquid L was apply | coated to the 2nd chamber 32 side can be provided. have.

(Example 3)

5 is a schematic view showing the structure of a vacuum drying apparatus of Example 3. FIG. In detail, it is schematic which showed the structure at the time of seeing the inside from the side surface of an apparatus.

As shown in FIG. 5, the vacuum drying apparatus 50 of the present embodiment includes a chamber having a first chamber 51 and a second chamber 52 for receiving a substrate W coated with a liquid L. 53, the vacuum pump 56 provided with the 2nd chamber 52 in a pressure-reduced state, and the chamber 53 partitioning the inside of the chamber 53 into the 1st chamber 51 and the 2nd chamber 52, and the chamber 53 The partition wall portion 68 is movable along the inner wall of the wall. Moreover, the vacuum gauge 54 which measures the decompression state of the 1st chamber 51, and the vacuum gauge 55 which measures the decompression state of the 2nd chamber 52 are provided.

On the inner bottom face of the first chamber 51, a mounting table 61 for mounting and placing the substrate W is provided. Further, the side wall of the first chamber (51) is connected to holes 67 a are formed, the one side of the inert gas of nitrogen in the first chamber (51) (N ₂₎ as possible the gas introduction pipe 64 is connected have. The other side of the pipe 64 is connected to an N ₂ gas supply source (not shown) via an N ₂ valve 59 as an inlet valve.

The connection hole 66 is formed in the side wall part of the 2nd chamber 52, and one side of the piping 63 is connected. The other side of the pipe 63 is connected to the vacuum pump 56 via the vacuum valve 57.

The inner wall of the chamber 53 is provided with a pair of upper and lower rails 60 near the center. Each rail 60 has a slide part 62, and the partition part 68 is supported between the upper and lower pair of slide parts 62. The lower slide 62 is engaged with a ball screw 65a parallel to the lower rail 60, and the ball screw 65a is rotated by a motor 65 attached to the outer wall of the chamber 53. Thereby, when the ball screw 65a is rotated by driving the motor 65, the slide part 62 coupled to this can be moved. That is, the partition wall part 68 supported by the pair of slide parts 62 can be moved. In this case, the pair of slides 62 need to have airtightness so that the first chamber 51 can be sealed by the partition wall 68. As a method of imparting airtightness, for example, a membrane made of resin or the like having no gas permeability is brought into close contact with the inner wall portion of the first chamber 51 and the slide portion 62, and stretched in response to the movement of the slide portion 62. (伸縮) How to install so that can be mentioned.

A conductance valve 58 as a communication valve is provided at substantially the center of the partition wall 68. As the conductance valve 58, the conductance variable valve of the "multiposition butterfly valve MBV-MP series" by FUJI Technology Inc. is used, for example. This conductance variable valve is provided with the butterfly valve in the communicating part 69 in the valve. The butterfly valve is driven by a servomotor to open and close the communication section 69, and can freely change the opening degree.

The pressure reduction drying apparatus 50 of Example 3 has the structure similar to the basic structure of the pressure reduction drying apparatus 10 of Example 1. As shown in FIG. However, the volume of the first chamber 51 can be changed by moving the partition wall 68. In this case, the volume of the 2nd chamber 52 can be changed in the range which becomes larger than the volume of the 1st chamber 51.

6 is a block diagram showing the electrical or mechanical configuration of the vacuum drying apparatus of the third embodiment. As shown in FIG. 6, the reduced pressure drying device 50 includes a calculation unit 71 having a CPU, a timer 72 for measuring time, and a storage unit 73 in which data on reduced pressure drying conditions such as a reduced pressure drying profile is stored. It has the control part 70 provided with. Two vacuum gauges 54 and 55 are electrically connected to the control part 70, and the pressure reduction state of each of the 1st chamber 51 and the 2nd chamber 52 can be detected as a pressure value. In addition, the vacuum pump 56 and the conductance valve 58 are electrically connected so that each drive is controlled. And all of the vacuum valve 57 and N ₂ the valve 59 is a solenoid-operated valve is used, these are also electrically connected to the control unit 70 is controlled to open and close. In addition, the motor 65 as a moving means is electrically connected, and the control part 70 can drive the motor 65 to move the partition part 68. In addition, an input unit 74 and a display unit 75 having a keyboard (or a drive device of a recording medium capable of receiving data between the recording medium) are electrically connected. From the input part 74, pressure reduction drying conditions, such as a pressure reduction drying profile, can be input and memorize | stored in the memory | storage part 73. The display unit 75 can display various types of input data or display the pressure values of the first chamber 51 and the second chamber 52 detected by the vacuum gauges 54 and 55 and the operation state of the reduced pressure drying device 50. Can be. The calculating part 71 can calculate the amount of evaporation of a solvent, etc. based on the data contained in the reduced pressure drying profile etc. memorize | stored in the memory | storage part 73, and the pressure value detected by the vacuum systems 54 and 55. FIG. In addition, the set pressure of the decompression drying operation as the control operation included in the decompression drying profile or the like can be read to execute the decompression drying operation.

Thus, the electrical or mechanical configuration of the pressure reduction drying apparatus 50 adds the motor 65 to the component of the pressure reduction drying apparatus 10 of Example 1 shown in the block diagram of FIG. 2, and drives the communication valve 8. The motor 12 is replaced with a conductance valve 58. For this reason, the pressure reduction drying apparatus 50 can perform the pressure reduction drying operation corresponding to each pressure reduction drying profile shown to Fig.3 (a)-(c). In particular, in the shape-controlled vacuum drying profile of FIG. 3B, the control unit 70 opens the conductance valve 58 to communicate the first chamber 51 and the second chamber 52 with the vacuum valve ( 57 is opened, and the vacuum pump 56 is driven to set the pressure in the chamber 53 to a predetermined operating pressure Ps. Next, the conductance valve 58 is closed to close the first chamber 51 (time t ₁ ). The pressure P ₁ in a closed first chamber (51) is allowed to stand until the time t ₂ is in operation pressure Ps + saturated vapor pressure Psa. The amount of solvent evaporation in the saturated state is determined by the vapor pressure and the volume of the first chamber 51. Therefore, according to the quantity of the liquid L applied, it becomes possible to adjust the volume of the 1st chamber 51 by moving the partition part 68 previously. Alternatively, it is possible to adjust the partition wall 68 so that the volume of the first chamber 51 is large once it is saturated, and to take out the solvent remaining in the liquid L again.

The effect of the said Example 3 has the same effect as the effect (1)-(5) of the said Example 1, and has the following effects.

(1) In the vacuum drying apparatus 50 of the third embodiment, the partition wall 68 which partitions the inside of the chamber 53 into the first chamber 51 and the second chamber 52 is formed of a motor as a moving means ( Since 65 is provided, the volume of the 1st chamber 51 can be changed, maintaining airtightness. That is, by adjusting the volume of the first chamber 51 in accordance with the amount of the applied liquid L, in particular in the shape-controlled pressure-reducing drying profile, more than most of the solvent evaporates the sealed first chamber 51. The reduced pressure drying apparatus 50 which can be made into an appropriate saturation state can be provided.

(Example 4)

7 is a schematic view showing the structure of a vacuum drying apparatus of Example 4. FIG. In detail, it is schematic which showed the structure at the time of seeing the inside from the side surface of an apparatus.

As shown in FIG. 7, the pressure reduction drying apparatus 80 of this Example is the 1st chamber 81 which accommodates the board | substrate W on which the liquid body L was apply | coated, and the plurality of (three) chamber 82a, The chamber 83 which consists of the 2nd chamber 82 which has 82b, 82c, the vacuum pump 86 provided with each chamber 82a, 82b, 82c of the 2nd chamber 82 in a pressure-reduced state, and the chamber The three partition walls 98a, 98b, 98c which divide the inside of the 83 with the 1st chamber 81 and the some chamber 82a, 82b, 82c are provided. Moreover, the vacuum gauge 84 which measures the pressure reduction state of the 1st chamber 81, and the three vacuum gauges 85a, 85b, 85c which measure the pressure reduction state of each chamber 82a, 82b, 82c are provided.

On the inner bottom surface of the first chamber 81, a mounting table 91 for mounting and placing the substrate W is provided. Further, the side wall of the first chamber 81, the connection hole 97 is are formed, the one side of the inert gas of nitrogen in the first chamber 81 (N ₂₎ as possible the gas introduction pipe 94 is connected have. The other side of the pipe 94 is connected to an N ₂ gas supply source (not shown) via an N ₂ valve 89 as an introduction valve.

Connection holes 96a, 96b, and 96c are formed in the bottoms of the chambers 82a, 82b, and 82c of the second chamber 82, respectively, and portions where the pipe 93 is divided into three are connected. It is. The other side of the piping 93 is connected to the vacuum pump 86 via each vacuum valve 87a, 87b, 87c provided in the branched part.

Conductance valves 88a, 88b, and 88c as communication valves capable of varying conductance similar to those in the third embodiment are provided at substantially the center of each of the partition walls 98a, 98b, and 98c. When each conductance valve 88a, 88b, 88c is opened, it is possible to make the 1st chamber 81 and the 2nd chamber 82 communicate with each communicating part 99a, 99b, 99c in the state which communicated. Do. In addition, if one of the conductance valves 88b and 88c is closed, it is possible to change the volume of the second chamber 82 in communication with the first chamber 81. In this case, in the state where the conductance valve 88a and the conductance valve 88c are closed and the conductance valve 88b is opened, the volume of the second chamber 82 is set to be larger than that of the first chamber 81. It is.

8 is a block diagram showing the electrical or mechanical configuration of the vacuum drying apparatus of the fourth embodiment. As shown in FIG. 8, the reduced pressure drying device 80 includes a calculation unit 101 having a CPU, a timer 102 for measuring time, and a storage unit 103 in which data on reduced pressure drying conditions such as a reduced pressure drying profile is stored. It has the control part 100 provided with. Four vacuum meters 84, 85a, 85b, 85c are electrically connected to the control part 100, and each pressure reduction of each chamber 82a, 82b, 82c of the 1st chamber 81 and the 2nd chamber 82 is carried out. The state can be detected as a pressure value. In addition, the vacuum pump 86 is electrically connected so that driving is controlled. Three conductance valves 88a, 88b, and 88c are electrically connected to each other, and the number of the plurality of chambers 82a, 82b, and 82c communicating with the first chamber 81 by driving them is controlled. The three vacuum valves 87a, 87b and 87c and the N ₂ valve 89 all use solenoid valves, and these are electrically connected to the control unit 100 to control the opening and closing. In addition, an input unit 104 and a display unit 105 having a keyboard (or a drive device of a recording medium capable of receiving data between the recording medium) are electrically connected. From the input part 104, decompression drying conditions, such as a decompression drying profile, can be input and can be memorize | stored in the memory | storage part 103. FIG. The display unit 105 displays the various types of input data and the pressure values of the first chamber 81 and the chambers 82a, 82b, 82c detected by the vacuum gauges 84, 85a, 85b, 85c, and the reduced pressure drying device. The operation state of 80 can be displayed. The calculating part 101 can calculate the evaporation amount of a solvent etc. based on the data contained in the pressure reduction drying profile etc. memorize | stored in the memory | storage part 103, and the pressure value which each vacuum gauge 84, 85a, 85b, 85c detects. . In addition, the set pressure of the decompression drying operation as the control operation included in the decompression drying profile or the like can be read to execute the decompression drying operation.

Thus, the electrical or mechanical configuration of the vacuum drying apparatus 80 adds an increased vacuum gauge or vacuum valve to the components of the vacuum drying apparatus 10 of Example 1 shown in the block diagram of FIG. The motor 12 to be driven is replaced with each conductance valve 88a, 88b, 88c. For this reason, the pressure reduction drying apparatus 80 can perform the pressure reduction drying operation corresponding to each pressure reduction drying profile shown to Fig.3 (a)-(c). In particular, in the steam amount controlled pressure-reducing drying profile of FIG. 3A, the controller 100 opens the conductance valves 88a and 88b to communicate the first chamber 81 with the two chambers 82a and 82b. The vacuum valves 87a and 87b are opened, and the vacuum pump 86 is driven to reduce the pressure to reach a predetermined operating pressure Ps. At least at the time t ₁ when the first chamber 81 reaches the operating pressure Ps, the conductance valve 88a is closed to seal the first chamber 81. At a time t ₂ at which the solvent of the liquid L in the first chamber 81 evaporates and the pressure P ₁ rises and a predetermined pressure difference ΔP occurs, the N ₂ valve 89 is opened to release the N ₂ gas. At the same time, the conductance valve 88a is opened to allow the first chamber 81 to communicate with the chambers 82a and 82b. As a result, the N ₂ gas containing the vapor of the solvent diffuses into the chambers 82a and 82b and is discharged by the vacuum pump 86. Thereafter, when the N ₂ gas is introduced, the pressure in the first chamber 81 and the chambers 82a and 82b increases, and the reduced-pressure drying operation until time t ₃ close to the pressure at the start is repeated. As described above, the solvent evaporation rate from the liquid L is lowered by repeating the vacuum drying operation. That is, it can be considered that the amount of evaporation per unit time decreases. When the vacuum drying apparatus 80 of the present embodiment is used, for example, the control unit 100 is vacuumed so that the volume on the second chamber 82 side becomes smaller in response to the decrease in the amount of evaporation of the solvent in the repeated process of the vacuum drying operation. By closing the valve 87b and the conductance valve 88b, it is possible to discharge the vapor of the evaporated solvent more quickly, even if the evacuation speed of the vacuum pump 86 is constant. Moreover, after completion | finish of a pressure reduction drying operation | movement once, it becomes possible to shorten the time required for the decompression process made into predetermined | prescribed operating pressure Ps again. For this reason, it becomes possible to perform the reduced pressure drying of the liquid L more efficiently.

The effect of the said Example 4 has the effect of the effect (1)-(5) of the said Example 1, and has the following effects.

(1) In the vacuum drying apparatus 80 of Example 4, the second chamber 82 has a plurality (three) of yarns 82a, 82b, 82c, and a plurality of chambers 82a, 82b, 82c is partitioned by partition walls 98a, 98b and 98c having conductance valves 88a, 88b and 88c, respectively. Therefore, when the conductance valves 88a, 88b and 88c are opened and closed, the volume of the second chamber 82 in communication with the first chamber 81 where the solvent is evaporated can be changed. That is, especially in the steam amount controlled pressure-reducing drying profile, by changing the volume of the second chamber 82 in accordance with the amount of evaporation in the first chamber 81, when the exhaust velocity of the vacuum pump 86 is constant, the vapor of the solvent evaporated. Can be discharged more quickly. In addition, after the decompression drying operation is finished once, the time required for the decompression process to be the predetermined operating pressure Ps can be shortened again. For this reason, the reduced pressure drying apparatus 80 which can dry the reduced pressure of the liquid L more efficiently can be provided.

Modifications other than the above embodiments are as follows.

(Modification 1) In the vacuum drying apparatus 10 of Example 1 and the vacuum drying apparatus 30 of Example 2, the structure of a 1st chamber and a 2nd chamber is not limited to this. For example, two chambers are provided, one side being a first chamber and the other side being a second chamber. And the communication part which connects two chambers, and the opening-closing means which can open and close a communication part are provided. Thereby, the pressure reduction drying apparatus which can respond to each pressure reduction drying profile shown to Fig.3 (a)-(c) can be provided.

(Modification 2) In the vacuum drying apparatus 10 of Example 1 and the vacuum drying apparatus 30 of Example 2, the rectifying plate provided in the 1st chamber is not necessarily required. The communication valves 8 and 38 have butterfly-shaped valves 8b and 38b. When the rotary shafts 8a and 38a are rotated at a predetermined angle by driving the motors 12 and 42, the valves 8b and 38b are provided. It is possible to give a rectifying function by).

(Modification 3) In the vacuum drying apparatus 10 of the first embodiment and the vacuum drying apparatus 30 of the second embodiment, the communication ports 19 and 49 and the communication valves 8 and 38 opening and closing the openings are provided. The structure is not limited to this. Conductance valves may be used in the same manner as in Examples 3 and 4. According to this, the exhaust and vapor discharge rates of the first chambers 1 and 31 can be changed by conductance valves. That is, in the board | substrate W accommodated in the 1st chambers 1 and 31, it becomes possible to suppress the rate at which the solvent evaporates from the liquid L. As shown in FIG.

(Modification 4) In the vacuum drying apparatus 50 of the third embodiment, the moving means for moving the partition wall 68 is not limited to this. For example, the partition wall 68 may be moved using an actuator such as an air cylinder instead of the motor 65. Moreover, when the chamber 53 is made into one substantially sealed cylinder structure, and the connecting rod which connects a piston with the partition part 68 as a piston is driven, the 1st chamber 51 and The volume of the second chamber 52 can be varied.

(Modification 5) The structures of the first chambers 1, 31, 51, and 81 are not limited thereto in each of the vacuum drying apparatuses 10, 30, 50, and 80 of the first to fourth embodiments. For example, heating means, such as a heater, can also be provided in the mounting bases 11, 41, 61, 91 which mount and arrange the board | substrate W. As shown in FIG. According to this, it becomes possible to fix the shape of the liquid body L more quickly by heating the board | substrate W uniformly by a heating means and promoting evaporation of a solvent in a pressure reduction drying process.

(Modification 6) In each of the pressure reduction drying apparatuses 10, 30, 50, and 80 of the above Examples 1 to 4, the dry matter to be dried under reduced pressure is applied to the substrate W to which the liquid L is coated. It is not limited. For example, a rounded object such as a semiconductor wafer or spectacle lens may be supported by a jig or the like and accommodated therein.

(Modification 7) The substrate W as a work to be dried under reduced pressure using each of the vacuum drying apparatuses 10, 30, 50, and 80 of the above Examples 1 to 4 includes a liquid L containing an alignment film forming material. Is not limited to that applied. For example, in the vacuum drying of the substrate W coated with various liquid bodies containing functional film-forming materials such as color element materials for color filters, light-emitting materials such as organic EL, conductive materials for circuit formation, and electron-emitting device-forming materials. Applicable

As described above, according to the present invention, in the drying process, the solvent evaporation rate of the applied liquid can be optimized according to the type of liquid, so that the drying can be performed under reduced pressure while the vapor pressure distribution of the solvent is approximately uniform. A reduced pressure drying apparatus can be provided.

Claims (14)

A reduced pressure drying device in which a workpiece coated with a liquid body containing a film-forming material is accommodated in a chamber, and the solvent of the liquid body is evaporated under reduced pressure to dry. The said chamber has a 1st chamber which can accommodate the said workpiece | work, and the 2nd chamber connected by the said 1st chamber and the communication part, Decompression means provided at least in a state capable of depressurizing the second chamber, A communication valve capable of opening and closing the communication section; And a control unit for controlling the open / closed state of the communication section by driving the pressure reducing means to control at least the decompression state of the second chamber and the communication valve. The method of claim 1, It further has a pressure gauge which can measure at least the decompression state of the said 1st chamber, The control unit drives the communication valve to communicate the first chamber and the second chamber, drives the decompression unit to connect the first chamber and the second chamber until the detected pressure of the pressure gauge reaches a predetermined operating pressure. After the pressure is reduced, the communication valve is driven to close the communication section to seal the first chamber, and when the pressure gauge detects that the first chamber rises to a predetermined pressure, the communication valve is driven to operate the first valve. A pressure reduction drying device, wherein a chamber and the second chamber communicate with each other to perform a control operation of discharging vapor of the solvent diffused into the first chamber and the second chamber by the decompression means. The method of claim 2, The predetermined pressure is a pressure obtained by adding a predetermined operating pressure to a vapor pressure of a predetermined amount of the solvent evaporated in the first chamber sealed. And the control unit discharges the vapor of the solvent diffused into the first chamber and the second chamber by the decompression means under a pressure equal to or greater than the predetermined pressure. The method of claim 2, The predetermined operating pressure is set to a pressure at which the viscosity increases until just before the viscosity at which the solvent evaporates from the liquid body and affects the film shape, And the predetermined operating pressure is added to the substantially saturated vapor pressure of the solvent evaporated in the first chamber in which the predetermined pressure is sealed. The method according to any one of claims 2 to 4, The said control part is the said 2nd of a non-communication state, until the vapor of the said solvent spread | diffused in the said 1st chamber and the 2nd chamber which communicated by driving the said communication valve by the said pressure reduction means is discharged. The pressure reduction drying apparatus is made to reduce the pressure by the said pressure reduction means to the pressure less than the said predetermined | prescribed operation pressure. The method of claim 2, The control unit repeatedly performs the control operation from the operation of depressurizing the first chamber and the second chamber in communication by the decompression means to the operation of discharging the vapor of the solvent diffused into the first chamber and the second chamber. A vacuum drying apparatus, characterized in that the execution. The method of claim 1, It further has a pressure gauge which can measure at least the decompression state of the said 2nd chamber, The controller controls the second chamber in a non-communication state by driving the communication valve to seal the first chamber, and then driving the decompression unit until the detected pressure of the pressure gauge reaches a predetermined operating pressure. Then, the communication valve is driven to open the communication section so that the first chamber and the second chamber communicate with each other and the vapor pressure of the solvent diffused into the first chamber and the second chamber is discharged by the decompression means. Performing a reduced pressure drying apparatus. The method of claim 2, And said predetermined operating pressure is set to a value higher than the vapor pressure of the solvent of said liquid body. The method of claim 1, The volume of the said 2nd chamber is set so that it may be larger than the volume of the said 1st chamber, The pressure reduction drying apparatus characterized by the above-mentioned. The method of claim 1, Further having an introduction valve capable of introducing an inert gas from outside to the at least first chamber, And the control unit drives the inlet valve to introduce an inert gas when at least the vapor of the solvent diffused into the first chamber is discharged. The method of claim 10, A rectifying plate is provided in the first chamber for rectifying flow when the introduced inert gas flows from the workpiece side in the direction of the communicating portion. The method of claim 1, And a variable means for varying the volume ratio of the first chamber and the second chamber. The method of claim 12, The chamber has a partition wall partitioning the interior of the chamber into the first chamber and the second chamber, and the variable means is a moving means for changing the volume ratio of the first chamber and the second chamber by moving the partition wall. Vacuum drying equipment. The method of claim 12, The second chamber has a plurality of chambers having communication valves that can communicate with each other, and the variable means drives the communication valve and the communication valve for communicating the plurality of chambers constituting the second chamber, and the chambers communicate with each other. It is a control part which changes the number of pressure reduction drying apparatuss characterized by the above-mentioned.

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