KR20110090773A - Decompression drying method and decompression drying apparatus - Google Patents

Abstract

PURPOSE: A decompression drying method and a decompression drying apparatus are provided to obtain the thickness of remaining film of a coating film and improved line width thereof in forming a wire pattern. CONSTITUTION: In a decompression drying method and a decompression drying apparatus, a solvent from a coating film is vaporized to dry a coating film under decompression environment. In a first step, a substrate having a coating film is received into a chamber and the pressure of a chamber is downed by a first decompression speed and is higher than the vapor pressure of a solvent(S1-S3). The pressure of the chamber is downed by second decompression speed until it is reached to the vapor pressure of the solvent.

Description

DECOMPRESSION DRYING METHOD AND DECOMPRESSION DRYING APPARATUS}

The present invention relates to a reduced pressure drying method and a reduced pressure drying apparatus for performing a drying treatment on a coating film on the substrate by placing a substrate to be coated with a coating liquid under a reduced pressure environment.

For example, in the manufacture of FPD (flat panel display), forming a circuit pattern by a so-called photolithography process is performed.

Specifically, the photolithography step is performed as follows.

First, a predetermined film is formed on a substrate to be treated, such as a glass substrate, and then a photoresist (hereinafter referred to as a resist) as a coating liquid is applied to form a resist film. And a resist film is exposed corresponding to a circuit pattern, and this develops.

In such a photolithography step, as shown in Fig. 8A, the resist pattern R is provided with different film thicknesses (thick film portion R1 and thin film portion R2), and the number of photomasks is subjected to etching treatment using this. It is possible to reduce the number of processes, and the number of processes. On the other hand, such a resist pattern R can be obtained by the half (halftone) exposure process using the halftone mask which has the part from which light transmittance differs with one sheet.

The circuit pattern formation process at the time of using the resist pattern R to which this half exposure was applied is demonstrated concretely using FIG.8 (a)-(e).

For example, in Fig. 8A, on the glass substrate G, a gate electrode 200, an insulating layer 201, an a-Si layer (non-doped amorphous Si layer) 202a and An Si layer 202 made of an n + a-Si layer 202b (phosphorus-doped amorphous Si layer) and a metal layer 203 for forming an electrode are sequentially stacked.

Furthermore, on the metal layer 203, the resist pattern R obtained by the said half exposure process and the development process is formed.

After forming this resist pattern R (thick film part R1 and thin film part R2), as shown in FIG.8 (b), the metal film is etched (1st etching) using this resist pattern R as a mask.

Subsequently, an ashing process is performed on the entire resist pattern R in the plasma. As a result, as shown in Fig. 8C, a resist pattern R3 having a film thickness of about half can be obtained.

As shown in Fig. 8D, using the resist pattern R3 as a mask, etching (second etching) to the exposed metal layer 203 or Si layer 202 is performed. By removing the resist R3 as shown in Fig. 8E, a circuit pattern can be obtained.

By the way, in the front-end process of the half exposure process for forming the said resist pattern R, after the coating process of the resist liquid to a board | substrate surface, the pressure reduction drying process which dries the applied resist film in a reduced pressure environment is performed.

In this vacuum drying process, the substrate to which the resist liquid is applied is accommodated in the chamber, the chamber is decompressed to the vapor pressure of the solvent in the resist liquid, and the drying process is performed by evaporating the solvent in the resist for a predetermined time.

On the other hand, Patent Document 1 discloses a reduced pressure drying apparatus for drying a coating liquid such as a resist liquid applied to a substrate under reduced pressure.

Japanese Laid-Open Patent Publication 2004-47797

However, the inventors of the present application, when the pressure in the chamber is reduced to the vapor pressure of the solvent at the time of the start, as in the conventional pressure-drying process, which has been conventionally performed, as shown in the measurement result of FIG. 9, the solvent boils rapidly from the resist film and evaporates. It was found that this adversely affects the uniformity of the resist film after drying under reduced pressure.

Furthermore, when the resist pattern R which has the thick film part R1 and the thin film part R2 was formed by half-exposure process as mentioned above, and it was ashed-processed like FIG.8 (c), the resist pattern R3 obtained as a residual film (FIG. 8) In (c)), it has come to discover that a nonuniformity arises by the nonuniformity of the said resist film.

Specifically, the problem that the film thickness of the residual film pattern and the line width are too small as shown in FIG. 10 (a) and the too large part as shown in FIG. 10 (b) are mixed in the substrate surface. There was.

The present invention has been made in view of the above-described problems of the prior art, and in a reduced pressure drying apparatus for performing a drying treatment on a coating film formed on a substrate to be treated, the in-plane uniformity of the coating film after the drying treatment is improved, and the wiring pattern Provided are a reduced pressure drying method and a reduced pressure drying apparatus capable of improving the uniformity of the remaining film thickness and line width of the coating film in the forming process.

In order to solve the said subject, the pressure reduction drying method which concerns on this invention is a pressure reduction drying method which evaporates the solvent in the said coating film, putting the to-be-processed substrate in which the coating film was formed in a reduced pressure environment, and performing the drying process of the said coating film, In the step of accommodating the substrate on which the coating film is formed in the chamber and setting the inside of the chamber in a reduced pressure environment, the pressure in the chamber is reduced at a first decompression rate to be higher than the vapor pressure of the solvent, and at least the solvent boils rapidly. And a step of setting a first pressure value that does not evaporate, and gently depressurizing at a second depressurization rate slower than the first depressurization rate until at least the vapor pressure of the solvent is reached from the first pressure value. have.

On the other hand, after the step of making the pressure in the chamber the vapor pressure of the solvent, it is preferable to further depressurize at the second depressurization speed to perform the step of setting the second pressure value lower than the vapor pressure of the solvent.

According to this method, the pressure in the chamber is higher than the vapor pressure of the solvent, and at least from the time point of the first pressure value at which the solvent does not boil and evaporate rapidly, the pressure is reduced by a slower second decompression rate. .

By this control, the pressure value near the board | substrate surface maintains a uniform state in surface without unevenness, and is pressure-reduced gently, and reaches the vapor pressure of a solvent.

As a result, evaporation by the rapid boiling of the solvent from the coating film is suppressed, and the solvent can be evaporated at low speed, and the dry state of the resist can be made uniform.

In addition, since the dry state of the resist becomes uniform, for example, the uniformity of the pattern residual film thickness and the line width in the wiring pattern forming process in the case of using the half exposure treatment can be improved.

Moreover, in order to solve the said subject, the pressure reduction drying apparatus which concerns on this invention places the to-be-processed board | substrate with a coating film in a reduced pressure environment, and evaporates the solvent in the said coating film, and performs the drying process of the said coating film. And a chamber for accommodating the substrate on which the coating film is formed, exhaust means for evacuating the inside of the chamber, exhaust amount adjusting means for adjusting the exhaust amount from the chamber, pressure detecting means for detecting the pressure in the chamber, and the pressure. On the basis of the detection result of the detection means, a control means for controlling the exhaust adjustment amount by the displacement adjustment means, the control means, the pressure in the chamber is higher than the vapor pressure of the solvent, at least the solvent is sudden The exhaust volume adjusting means is controlled so as to depressurize at the first depressurization rate until the first pressure value does not boil and evaporate. It is characterized by controlling the displacement amount adjusting means so as to gently depressurize at a second depressurization speed slower than the first depressurization speed from the first pressure value until at least the vapor pressure of the solvent is reached.

On the other hand, it is preferable that the said control means controls the said displacement adjustment means so that pressure may be gently reduced at the said 2nd pressure reduction speed until the pressure in the said chamber becomes a 2nd pressure value lower than the vapor pressure of the said solvent.

According to such a structure, evaporation by the rapid boiling of the solvent from a coating film is suppressed, the solvent can be evaporated at low speed, and the dry state of a resist can be made uniform.

In addition, since the dry state of the resist becomes uniform, for example, the uniformity of the pattern residual film thickness and the line width in the wiring pattern forming process in the case of using the half exposure treatment can be improved.

According to the present invention, in the reduced pressure drying apparatus for performing a drying treatment on a coating film formed on a substrate to be treated, the in-plane uniformity of the coating film after the drying treatment is improved, and the remaining film thickness and line width of the coating film in the wiring pattern forming process A reduced pressure drying method and a reduced pressure drying apparatus capable of improving uniformity can be obtained.

1 is a cross-sectional view showing an overall schematic configuration of a first embodiment according to the present invention.
2 is a flowchart showing the operation of the first embodiment according to the present invention.
3 is a graph showing the pressure reduction control in the chamber in the first embodiment according to the present invention.
4 is a graph showing the pressure change in the chamber in Examples 1 to 4 according to the present invention.
5 is a graph showing the change in the evaporation rate of the solvent of the resist in Examples 1 to 4 according to the present invention.
6 is a graph showing the pressure change in the chamber in Examples 5 to 7 according to the present invention.
7 is a graph showing the change in the evaporation rate of the solvent of the resist in Examples 5 to 7 according to the present invention.
8A to 8E are cross-sectional views for explaining a series of steps for forming a wiring pattern using a half exposure process.
9 is a graph showing a change in pressure in the chamber and a change in the evaporation rate of the solvent of the resist as a measurement result when a conventional vacuum drying method is used.
10 (a) and 10 (b) are cross-sectional views for explaining the non-uniformity of the resist pattern residual film in the process of forming the wiring pattern using the half exposure process.
11 is a flowchart showing the operation of the second embodiment according to the present invention.
12 is a graph showing the pressure reduction control in the chamber in the second embodiment according to the present invention.

Below, 1st Embodiment which concerns on the pressure reduction drying method and pressure reduction drying apparatus of this invention is demonstrated based on FIG.

As shown in FIG. 1, this pressure reduction drying apparatus 1 is provided with the chamber 2 for maintaining the internal space in airtightness, This chamber 2 has the lower chamber 2a, and the upper part. And an upper chamber 2b provided to be movable up and down so as to cover the top.

The lower chamber 2a is provided with a stage 4 for placing a glass substrate G as a substrate to be processed, and the stage 4 is capable of lifting and lowering the shaft 6 in order to facilitate carrying in and out of the substrate. Supported by On the stage 4, a plurality of fixing pins 5 for mounting the substrate G are provided, and the plurality of fixing pins 5 are arranged on the stage 4 in a dispersed manner. On the other hand, it is preferable that this fixing pin 5 is formed with the material (glass in this embodiment) substantially the same as the board | substrate G.

In addition, four exhaust ports 10 (in FIG. 1, two of them) are provided at each corner portion of the lower chamber 2a. An exhaust pipe 11 is connected to each exhaust port 10 in series, and the exhaust pipe 11 is connected to an exhaust pump 17 (exhaust means). That is, the upper chamber 2b is in close contact with the lower chamber 2a and the inside of the chamber 2 is hermetically sealed and exhausted through the exhaust pipe 11 by the exhaust pump 17, whereby the inside of the chamber 2 is decompressed and predetermined. It is configured to be in a vacuum state of.

In the middle of the exhaust pipe 11, a flow regulating valve 15 (exhaust amount adjusting means) and a main valve 16 are provided. The valve opening degree is controlled by the control part 20 comprised with a computer, and the said flow regulating valve 15 determines the displacement amount from the inside of the chamber 2 according to this opening degree.

In addition, the exhaust pipe 11 is provided with a pressure detecting unit 18 (pressure detecting means) for detecting the pressure in the chamber 2, and the control unit 20 adjusts the flow rate based on the detection result of the pressure detecting unit 18. The valve opening degree of the valve 15 is set.

In addition, in order to perform the pressure reduction in the chamber 2 based on constant control, the control part 20 memorize | stores a predetermined | prescribed control program, and this control program is executed when starting a pressure reduction drying process.

On the other hand, as shown in Fig. 3, the control program performs control so that the pressure in the chamber 2 changes with time. In addition, although it is assumed that pressure changes linearly as the pressure line shown by the solid line in FIG. 3, it is not limited to this, You may perform control to change it as shown by a dashed-dotted line.

Next, the vacuum drying process using the said control program is demonstrated.

In the shearing step, when a resist liquid, which is a coating liquid, is applied to the surface to be processed of the substrate G, the substrate G is loaded into the vacuum drying apparatus 1 and placed on the stage 4.

Moreover, the upper chamber 2b is closed with respect to the lower chamber 2a, and the board | substrate G is accommodated in the chamber 2 of airtight state (step S1 of FIG. 2).

When the chamber 2 is in an airtight state, the exhaust pump 17 is driven and the main valve 16 is opened, and the exhaust in the chamber 2 is started from time t0 in FIG. 3.

Here, the control part 20 first pressure-reduces the inside of the chamber 2 at the 1st pressure reduction speed v1, as shown in FIG. 3 by adjusting the opening degree of the flow regulating valve 15, and in the chamber 2, as shown in FIG. The pressure is set to the first pressure value P1 (for example, 400 Pa at the time point t1 in FIG. 3) higher than the vapor pressure Pe of the solvent (for example, PGMEA) of the resist liquid (step S2 in FIG. 2). On the other hand, this first pressure value P1 is higher than the pressure value at which the solvent boils and evaporates rapidly, and the solvent does not evaporate and evaporate rapidly, for example, when the solvent does not evaporate at all, and somewhat. It is a pressure value including the case of evaporating (for example, the case of the evaporation rate of about 30sec of FIG. 5). In addition, the vapor pressure of the solvent here shows the value of the vapor pressure in pressure reduction environment.

When the pressure in the chamber 2 reaches the 1st pressure value P1, the control part 20 adjusts the opening degree of the flow regulating valve 15 to the direction which closes, and reduces the displacement, and the said 1st decompression rate v1 The pressure is reduced slowly at the slower second decompression speed v2 (step S3 in FIG. 2).

The gentle decompression control by the second decompression rate v2 is performed from the time point t1 of the first pressure value P1 to the time point t3 of the second pressure value P2 (for example, 250 Pa) as shown in FIG. 3.

On the other hand, the said 2nd pressure value P2 is a value lower than the vapor pressure Pe of the solvent of a resist, and at the time t3 when evaporation of the solvent in a resist is completed, when pressure_reduction | reduced_pressure continues gently by the said 2nd pressure reduction rate v2. Pressure value. The said 1st pressure value P1 and the 2nd pressure value P2 are preset according to various conditions, such as a kind of solvent.

Here, the control part 20 is based on the detection result of the pressure detection part 18, until the pressure in the chamber 2 is pressure-reduced from the 1st pressure value P1 to the 2nd pressure value P2, and the chamber 2 is carried out. It is monitored whether or not the decompression speed in the motor is in the vicinity of the second deceleration speed v2 (within a predetermined range) (step S4 in Fig. 2).

And when the decompression speed in the chamber 2 is slower than a predetermined range (step S5 of FIG. 2), the opening degree of the flow regulating valve 15 is enlarged so that exhaust flow volume may increase (step S6 of FIG. 2). On the other hand, when the decompression speed in the chamber 2 is faster than the predetermined range (step S5 of FIG. 2), the opening degree of the flow regulating valve 15 is made small so that exhaust flow volume may decrease (step S7 of FIG. 2).

In addition, as shown in FIG. 3, at the time point t2 while the pressure in the chamber 2 is gently reduced from the first pressure value P1 to the second pressure value P2, the pressure in the chamber 2 is the vapor pressure Pe of the solvent. To reach.

For this reason, a little while before the time point t2 when the pressure in the chamber 2 reaches the vapor pressure Pe gently, the evaporation of the solvent starts at low speed (without sudden boiling), and furthermore, while the second pressure P2 is reached, Over time, the solvent evaporates at a stable evaporation rate.

When the pressure in the chamber 2 is reduced to the second pressure value P2 (step S8 in FIG. 2), the evaporation of the solvent in the resist is substantially completed, and the control unit 20 stops driving the exhaust pump 17. Then, the vacuum drying process is complete | finished (step S9 of FIG. 2).

As described above, according to the embodiment of the present invention, the pressure in the chamber 2 is higher than the vapor pressure of the solvent of the resist, and at least from the time point t1 of the first pressure value P1 at which the solvent does not boil and evaporate at least. Decompression is performed by the slow decompression velocity v2.

By this control, the pressure in the vicinity of the substrate surface is smoothly decompressed while maintaining a uniform in-plane state without variation, and reaches the vapor pressure of the solvent.

As a result, evaporation by the rapid boiling of the solvent from the resist film is suppressed, and the solvent can be evaporated at low speed, and the dry state of the resist can be made uniform.

In addition, since the dry state of the resist becomes uniform, the uniformity of the remaining film thickness and the line width of the resist pattern in the wiring pattern forming process in the case of using a half exposure process can be improved, for example.

On the other hand, in the said embodiment, although the flow regulating valve 15 was provided as the displacement adjustment means in the pressure reduction drying apparatus 1, it was set as the structure which controls the displacement amount from the chamber 2 by adjusting the opening degree. In the invention, the configuration is not limited.

For example, an air introduction means (not shown) for flowing air into the exhaust pipe 11 in place of the flow rate adjustment valve 15 may be provided, and the amount of air introduced may be adjusted to control the displacement. good.

In addition, as demonstrated using FIG. 3, in pressure control, although the 1st pressure value P1 and the 2nd pressure value P2 were set, it was made to control the decompression speed until reaching those pressure values, but setting of a pressure value You may further increase the number and more precisely control the decompression rate.

For example, as shown in FIG. 3, the 3rd pressure value P3 and the 4th pressure value P4 are further added to the 1st pressure value P1 vicinity, and the pressure reduction control until it reaches the 1st pressure value P1 is carried out. You may carry out more finely. For example, the 5th air pressure value P5 and the 6th air pressure value P6 may be provided between the 1st pressure value P1 and the 2nd pressure value P2, and the pressure reduction control of vapor pressure Pe vicinity may be performed more finely. .

Moreover, in the said embodiment, although it set as the structure which mounts the board | substrate G on the stage 4 in the chamber 2, it is not limited to the structure, For example, a support pin or a conveyance roller It may be a configuration placed on the rollers.

[Example]

Next, the coating film formation direction and coating film forming apparatus which concern on this invention are further demonstrated based on an Example.

[Examples 1 to 4]

In Examples 1 to 4, the glass substrate coated with the resist was housed in an airtight chamber, and depressurized to a pressure value 400 Pa corresponding to the first pressure value P1 in the above embodiment, over a predetermined time period. The pressure was reduced to a predetermined pressure value corresponding to the second pressure value P2. And while depressurizing from 400 Pa to 2nd pressure value P2, it was verified how the evaporation rate of a solvent changes.

In addition, AZ-SR210 (AZ company) was used for the resist, and PGMEA was used for the solvent, and the coating film thickness of the resist film was 1.5 micrometers.

The pressure value corresponding to the second pressure value P2 was set to 250 Pa in Example 1, 200 Pa in Example 2, 150 Pa in Example 3, and 100 Pa in Example 4.

The pressure change in the chamber in each of Examples 1 to 4 is shown in FIG. 4. In addition, the change of the evaporation rate of the resist solvent at that time is shown in FIG.

5, in the case of Example 1 (400 Pa-250 Pa) with the slowest decompression rate, it was confirmed that since the change of the evaporation rate of a solvent is the smallest and evaporation by a sudden boiling does not occur, it is preferable.

[Examples 5 to 7]

In Examples 5 to 7, the pressure value corresponding to the first pressure value P1 in the above embodiment is set to 400 Pa, the predetermined pressure value corresponding to the second pressure value P2 is set to 250 Pa, and the pressure is reduced from 400 Pa to 250 Pa. It was verified how the evaporation rate of the solvent changed over time.

In addition, the resist, the solvent, and the coating film thickness were made the same as Examples 1-4.

In addition, the time until pressure_reduction | reduced_pressure from 400 Pa to 250 Pa was made into 35 sec in Example 5, 25 sec in Example 6, and 15 sec in Example 7.

The pressure change in a chamber in each Example 5-7 is shown in FIG. Moreover, the change of the evaporation rate of the resist solvent at that time is shown in FIG.

It was confirmed from FIG. 7 that in the case of Example 5 where the decompression rate was gentle by taking the most time, the change in the evaporation rate of the solvent was the smallest, and evaporation due to rapid boiling did not occur.

From the results of the above Examples 1 to 7, the boiling point of the solvent from the resist film is rapidly reduced by slowly depressurizing the first pressure value P1 at which the solvent of the resist liquid does not boil and evaporate at least. It was confirmed that evaporation by was suppressed and that the solvent was evaporated at a low speed.

Example 8

In Example 8, the pressure value corresponded to the 1st pressure value P1 in the said embodiment was set to 400 Pa, and the predetermined pressure value corresponded to the 2nd pressure value P2 was set to 250 Pa, and it reduced pressure from 400 Pa to 250 Pa.

The half exposure process was performed using the obtained resist film, About 25 pattern points in the inside of a board | substrate surface were measured about the pattern line width and the residual film thickness of the obtained resist pattern, and the fluctuation range (nonuniformity) was calculated | required. In addition, at each measurement point, the taper angle (the inclination angle with respect to a board | substrate surface: (theta) angle shown to FIG. 8 (c)) of a resist pattern cross section was measured, and those average values were calculated | required.

In addition, as Comparative Example 1, the fluctuation range was changed in the same manner as in Example 8 with respect to a conventional vacuum drying method, that is, a substrate subjected to a drying process by rapidly reducing the chamber pressure to the vapor pressure of a solvent of a resist and maintaining the pressure. And taper angles were obtained.

In addition, AZ-SR210 and the solvent PGMEA were used for the resist in Example 8 and the comparative example 1, and the coating film thickness of the resist film was 2.2 micrometers.

Table 1 shows the results of Example 8 and Comparative Example 1.

Residual film thickness (㎛) Line width (㎛) Taper Angle (°) Example 8 0.37 0.67 60.19 Comparative Example 1 0.63 1.09 81.81

As shown in Table 1, according to Example 8 to which the reduced-pressure drying method according to the present invention was applied, the variation width (nonuniformity) of both the remaining film thickness and the line width of the resist pattern was reduced, compared to the result of Comparative Example 1 to which the conventional method was applied, and the substrate was larger than before. It was confirmed that uniformity in surface improves.

In addition, the taper angle is smaller than that of Comparative Example 1 in Example 8, and from this verification result, the taper angle of the resist pattern can be arbitrarily controlled by controlling the inclination (evaporation rate) of the first pressure value P1 to the vapor pressure Pe. It was confirmed.

Next, a second embodiment of the present invention will be described. In this embodiment, the step at the time of depressurizing the inside of the chamber 2 is partially different from the above-mentioned embodiment. In addition, description is abbreviate | omitted about the same part as embodiment mentioned above.

As shown in FIG. 11, when the chamber 2 is in an airtight state, the exhaust pump 17 is driven and the main valve 16 is opened. And the control part 20 adjusts the opening degree of the flow regulating valve 15, and exhaust gas in the chamber 2 is started from time t0 of FIG. Then, the pressure is reduced until the predetermined tenth pressure value P10 (for example, 70000 Pa at the time point t10 in FIG. 12) is reached at the third decompression speed v3 slower than the first decompression speed v1 (step in FIG. 11). S10). In addition, the decompression rate v3 at this time is a decompression rate at which the resist liquid applied to the substrate G does not boil rapidly, and is for preventing the surface of the resist liquid from roughening by rapid boiling.

When the pressure in the chamber 2 reaches the pressure value P10, the control unit 20 adjusts the opening degree of the flow regulating valve 15 in the opening direction, increases the displacement and reduces the pressure at the first decompression speed v1, The pressure is reduced until the first pressure value P1 (for example, 400 Pa at the time point t1 in FIG. 12) is reached (step S2 in FIG. 11).

When the pressure in the chamber 2 reaches the 1st pressure value P1, the control part 20 adjusts the opening degree of the flow regulating valve 15 to the direction which closes, and reduces the displacement, and the said 1st decompression rate v1 Slowly decompression is performed at the slower second decompression velocity v2 (step S3 in FIG. 11).

The gentle decompression control by the second decompression rate v2 reaches the time point t11 of the predetermined eleventh pressure value P11 (for example, 350 Pa) from the time point t1 of the first pressure value P1 as shown in FIG. 12. Until it is done. On the other hand, the pressure value P11 is a value lower than the vapor pressure Pe of the solvent of a resist, and is higher than the said 2nd pressure value P2. Here, the pressure value P11 is preset according to various conditions, such as a kind of solvent.

Here, the control unit 20 reduces the pressure in the chamber 2 on the basis of the detection result of the pressure detector 18 until the pressure in the chamber 2 decreases from the first pressure value P1 to the pressure value P11. It is monitored whether or not the speed is near the second decompression speed v2 (within a predetermined range) (step S4 in FIG. 11).

And when the decompression speed in the chamber 2 is slower than a predetermined range (step S5 of FIG. 11), the opening degree of the flow regulating valve 15 is enlarged so that exhaust flow volume may increase (step S6 of FIG. 11). On the other hand, when the depressurization speed in the chamber 2 is faster than the predetermined range (step S5 of FIG. 11), the opening degree of the flow regulating valve 15 is made small so that exhaust flow volume may decrease (step S7 of FIG. 11).

In addition, as shown in FIG. 12, the pressure in the chamber 2 reaches the vapor pressure Pe of the solvent at the time point t2 while the pressure in the chamber 2 is gently reduced from the first pressure value P1 to the pressure value P11. do.

For this reason, the evaporation of a solvent starts at a low speed (without boiling rapidly) from a little before the time point t2 when the pressure in the chamber 2 reaches the vapor pressure Pe gently, and it takes time while reaching the pressure value P11. Evaporation of the solvent proceeds at a stable evaporation rate.

Then, when the pressure in the chamber 2 is reduced to the pressure value P11 (step S11 in FIG. 11), the opening degree of the flow rate control valve 15 is increased to increase the exhaust flow rate, and thus the fourth faster than the second decompression speed v2. The pressure is reduced to the second pressure value P2 at the decompression speed v4 (step S12 in FIG. 11). On the other hand, at the time point t11, the surface of the resist is almost dried, and even if the decompression speed is increased from v2 to v4, a defect in processing does not occur.

When the pressure in the chamber 2 is reduced to the second pressure value P2, the evaporation of the solvent in the resist is substantially completed, and the control unit 20 stops driving of the exhaust pump 17 to complete the reduced pressure drying process. (Step S13 of FIG. 2).

As described above, according to the second embodiment according to the present invention, in addition to the above-described embodiment, it is possible to prevent rapid boiling at the start of decompression, thereby preventing the surface of the resist film from roughening and Until the pressure value P2 is reached from the value P11, the pressure is further reduced at a decompression rate v4 faster than the decompression rate v2, so that the processing can be completed in a shorter time than the above-described embodiment.

In addition, similarly to step S4, step S5, step S6, step S7, and step S11 of FIG. 11 in step S10 in 2nd Embodiment, you may control exhaust operation until the pressure value P10 is reached by the 3rd decompression speed v3. In addition, similarly, in step S12, the exhaust operation may be controlled until the pressure value P2 is reached at the fourth decompression speed v4.

1: Decompression Dryer
2: chamber
2a: lower chamber
2b: upper chamber
4: stage
5: fixed pin
6: lifting shaft
10: air vent
11: exhaust pipe
15: flow rate adjusting valve (exhaust amount adjusting means)
16: main valve
17: exhaust pump (exhaust means)
20: control unit
G: glass substrate (processed substrate)
P1: first pressure value
P2: second pressure value
Pe: vapor pressure of the solvent
P10: tenth pressure value
P11: eleventh pressure value
v1: first decompression speed
v2: second decompression speed
v3: third decompression speed
v4: fourth decompression speed

Claims (4)

A pressure-sensitive drying method for evaporating a solvent in the coating film in a reduced pressure environment on a substrate to be coated with a coating film, and performing a drying treatment of the coating film.
In the process of accommodating the said board | substrate with which the coating film was formed in the chamber, and making the inside of the chamber into a reduced pressure environment,
Depressurizing the pressure in the chamber at a first depressurization rate to a first pressure value that is higher than the vapor pressure of the solvent and at least that the solvent does not boil and evaporate rapidly;
And depressurizing gently at a second depressurization rate slower than the first depressurization rate from the first pressure value until at least the vapor pressure of the solvent is reduced. The method of claim 1,
After the step of making the pressure in the chamber the vapor pressure of the solvent,
And depressurizing at the second depressurization rate, thereby performing a step of setting the second pressure value lower than the vapor pressure of the solvent. A pressure-sensitive drying apparatus for evaporating a solvent in the coating film in a reduced pressure environment on a substrate to be coated with a coating film, and performing a drying treatment of the coating film.
A chamber accommodating the substrate on which the coating film is formed, exhaust means for evacuating the chamber, exhaust amount adjusting means for adjusting the exhaust amount from the chamber, pressure detecting means for detecting pressure in the chamber, and pressure detecting means. Control means for controlling an exhaust adjustment amount by said exhaust amount adjustment means, based on a detection result of
Wherein,
Controlling the displacement amount adjusting means so as to reduce the pressure at a first depressurization rate until the pressure in the chamber is higher than the vapor pressure of the solvent and becomes at least a first pressure value at which the solvent does not boil rapidly and evaporate,
And the exhaust amount adjusting means is controlled so as to gently depressurize at a second depressurization rate slower than the first depressurization rate from at least the first pressure value until the vapor pressure of the solvent is reached. The method of claim 3,
Wherein,
And the exhaust amount adjusting means is controlled such that the pressure in the chamber is gently depressurized at the second depressurization rate until the second pressure value is lower than the vapor pressure of the solvent.

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