JP2005329303A - Method of manufacturing sheet type coated member, vacuum drying method and vacuum drying apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the occurrence of drying ununiformity in a sheet type coated substrate by fixing a drying condition suitable for every coating material and coating condition. <P>SOLUTION: This vacuum drying apparatus 10 is provided with: an upper part chamber 11 and a lower part chamber 12 to seal the sheet type coated substrate on which a coating member is applied in a vacuum chamber 13; a stage 15 provided in the vacuum chamber 13 and capable of placing the sheet type coated substrate having ≥1 m<SP>2</SP>surface area, a vacuum pump 20 for evacuating the vacuum chamber 13, a pressure detector 29 for detecting the pressure in the vacuum chamber 13; and a control part 30 for observing the change of pressure detected by the pressure detector 29 with time and judging the drying state of the sheet type coated substrate based on the observed change. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a single-wafer application member such as a display member, and more particularly to a manufacturing method for manufacturing a single-wafer application member using a vacuum drying method.

  Conventionally, for example, there has been an operation of applying various fluid materials (coating liquid, coating fluid) such as an insulating material and a photoresist liquid to a coating substrate (sheet) such as a flat plate made of glass used in various display devices such as a liquid crystal display. Has been done. Known coating methods include spin coating, die coating (slit coating), curtain coating, roll coating, bar coating, and the like. It is possible to form a coating layer with a sufficient thickness. Further, when the coating solution is a solution of an organic solvent or the like, generally, the organic solvent component is volatilized by leaving, heating, decompressing treatment or the like. In particular, from the viewpoint of processing efficiency, heating and / or pressure reduction processing using a vacuum drying processing apparatus is performed.

  On the other hand, even if a coating layer having a uniform film thickness is formed on a substrate using the coating method as described above, for example, the coating layer after being dried using a reduced-pressure drying apparatus is not necessarily uniform. There is a problem that should not be. In addition, from the viewpoint of the production efficiency of the coated substrate, it may be necessary to restore the pressure in a state where all the organic solvents and the like are not completely volatilized. There was a problem that it was wet again after the decompression. In order to solve these problems, as a conventional technique described in the publication, there is a technique that forms a film having no defect by using a combination of reduced-pressure drying and heat drying to shorten the required time (for example, Patent Document 1). reference.).

Japanese Patent Laid-Open No. 9-24336 (page 4, FIG. 1)

Here, in recent years, a large-screen liquid crystal display has been developed at a very high speed, and a substrate itself to be coated in a single-wafer coating manufacturing process such as a display member has been enlarged, and a vacuum drying apparatus has also been enlarged. For example, in a liquid crystal display using a large glass substrate, there is a liquid crystal display having an area of more than 1 m ² , and in the near future, coating and drying are performed on a glass substrate exceeding ² to 3 m ^2. It will be necessary to do it. However, in the manufacture of such a large substrate, when the applied coating solution is dried or when the coating solution applied to the substrate having a fine concavo-convex structure is dried, the coating thickness coating after drying is applied. The problem of non-uniform surface characteristics is particularly likely to occur. As a result, differences in optical characteristics, electrical characteristics, mechanical characteristics, and the like are likely to occur depending on the location of the substrate, making it difficult to use as a substrate having uniform performance. In the technique of the above-mentioned patent document, slight temperature unevenness generated on the substrate during heating tends to become unevenness emphasized during drying under reduced pressure, and it is difficult to perform uniform processing on a large coated substrate.

The present invention has been made to solve the technical problems as described above, and an object of the present invention is to easily determine the drying conditions and improve the production operation rate.
Another object is to shorten the manufacturing tact by reducing the margin of the drying conditions.
Still another object is to improve the production yield and the production quality by suppressing the occurrence of defective drying due to process variations.

  As a result of intensive studies to solve such problems, the present inventors have found that there is a certain relationship between the dry state of a large coated substrate and the pressure change in the chamber, and have reached the present invention. That is, a method for manufacturing a single wafer application member to which the present invention is applied includes an application step of applying a fluid material onto a substrate of a single wafer, and a single wafer application member to which the fluid material has been applied in this application step is subjected to a vacuum drying process. The reduced-pressure drying process includes a reduced-pressure drying process in which the pressure in the reduced-pressure drying apparatus during the reduced-pressure drying process of the single-wafer coating member is monitored. It is characterized by grasping the dry state of the leaf application member.

Here, in this vacuum drying process step, when a diagram of the pressure and time in the vacuum drying processing apparatus during the vacuum drying process of the single-wafer coating member is drawn, the slope of the slope that would be drawn in the graph is drawn. The bending point is determined as the drying end point of the single wafer coating member. More specifically, the first inflection point (first inflection point) is determined as the drying start point out of the two inflection points of inclination that will be drawn in the diagram, and the second inflection point is defined as the drying end point. The feature of the determination is excellent in that it is easy to determine the drying conditions, the margin for satisfying the drying conditions can be minimized, and the reduced-pressure drying treatment process can be shortened.
In addition, the single-wafer substrate coated with a fluid material by this coating process and dried under reduced pressure by the reduced-pressure drying process can be a large-sized coated substrate having an area of 1 m ² or more.

  On the other hand, the present invention is a reduced-pressure drying method for drying a coating member coated with a fluid on a substrate using a reduced-pressure drying processing apparatus, and each time in the reduced-pressure drying processing apparatus during the drying process of the coating member. A measurement step for measuring the pressure of the coating member, an observation step for observing a change of the measured pressure with respect to time, and a determination step for determining a drying end point of the application member based on the observed change.

Here, if this determination step is characterized in that the inflection point at which the tendency of the change in pressure with respect to time observed by the observation step changes is determined as the drying end point, the drying end point can be accurately determined, and the drying due to process fluctuations can be determined. This is also preferable from the viewpoint of preventing the occurrence of defects.
In particular, this observation step draws a diagram of the pressure and time measured by the measurement step, and this judgment step judges that the second inflection point appearing in the slope of the diagram drawn by the observation step is the drying end point. It can be characterized by.

Further, it may be characterized by further comprising an excessive exhaust step of exhausting excessively to a pressure value that is constant lower than the drying end point determined in this determination step, or for a predetermined long time.
Further, the present invention may further include an exhaust step for exhausting to a pressure value that is constant higher than the end point of drying determined in this determination step, or for a certain short time.

From another point of view, the reduced-pressure drying apparatus to which the present invention is applied includes a chamber for sealing a single-wafer coated substrate coated with a coating member in a decompression chamber, and the chamber is provided in the chamber and has an area of 1 m ² or more. A stage on which a single wafer coated substrate can be placed, a vacuum pump that depressurizes the decompression chamber, a pressure detector that detects the pressure in the decompression chamber, and changes in pressure detected by the pressure detector over time are observed. And a control unit for determining the dry state of the single wafer coated substrate based on the observed change.
Here, the pressure detector may be characterized by using a diaphragm type sensor.

  According to the present invention, by determining an appropriate drying condition for each coating material and coating condition, it is possible to suppress the occurrence of drying unevenness in the single wafer coated substrate.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
The description of the constituent requirements described below is an example (representative example) of the embodiment of the present invention, and the present invention is not limited to these contents.
FIG. 1 is a configuration diagram illustrating a reduced-pressure drying apparatus 10 to which the present exemplary embodiment is applied. The reduced-pressure drying apparatus 10 includes an upper chamber 11 and a lower chamber 12 as chambers, and the reduced-pressure chamber 13 as a sealed space capable of holding a reduced pressure by closing and integrating the upper chamber 11 and the lower chamber 12. Is forming. A vacuum seal member 14 is provided at a joint portion for closing the upper chamber 11 and the lower chamber 12. This vacuum seal member 14 can prevent or reduce leakage of reduced pressure in the reduced pressure chamber 13. The material of the vacuum seal member 14 is not particularly limited, and various elastomers, rubbers, resins, metals, and the like can be used. Further, the upper chamber 11 and the lower chamber 12 are relatively moved up and down by a lifting device (not shown).

The cross-sectional area of the horizontal plane of the decompression chamber 13 that determines the chamber volume is determined so that the coating substrate having the maximum area that can be stored is ensured with a minimum gap between the coating substrate to be placed (single-wafer coating substrate) and the side wall. It is preferable to be as close as possible. Since the decompression speed is determined from the displacement and the chamber volume, the drying efficiency can be increased by reducing the chamber volume. The reduced-pressure drying processing apparatus 10 to which the present embodiment is applied is suitably used for drying on a coating substrate having an area of 1 m ² or more as the area of the coating portion. Yes.

  Moreover, the reduced-pressure drying processing apparatus 10 includes a stage 15 for placing a coating substrate for drying. The stage 15 is provided with a fixing pin 15a for positioning the coating substrate and preventing damage when the coating substrate is placed. The material of the fixing pin 15a is not particularly limited, and various elastomers, rubbers, resins, metals, glass, and the like can be used. However, those that do not damage the coated substrate and do not leave pin marks, and those that do not deform by the weight of the coated substrate and tilt the coated substrate are preferred, and resins with low thermal conductivity (such as polyimide) are preferred. Can be used. When the stage 15 partially supports the coated substrate, the coated substrate may be deformed or warped. Therefore, the stage 15 preferably supports the entire surface of the coated substrate at the bottom. The stage 15 is normally held horizontally so that the coating solution on the coated substrate is uniformly dried, but depending on the shape of the coated substrate, the stage 15 is set so that the coating solution on the substrate is horizontal. It is also effective to provide a special structure.

  Further, the reduced-pressure drying processing apparatus 10 is provided at a lifting shaft 16 for adjusting the height of the coating substrate placed on the stage 15, and a joint portion between the lifting shaft 16 and the lower chamber 12. And a vacuum seal member 17 for preventing or reducing leakage of the internal decompression. The elevating shaft 16 is connected to an external driving device (not shown) through the lower chamber 12. The elevating shaft 16 can also be configured to rotate the stage 15 around the elevating shaft 16. The structure and material of the vacuum seal member 17 are not limited as long as the vacuum seal member 17 can maintain the degree of decompression of the decompression chamber 13. When it is possible to rotate around the elevating shaft 16, the stage 15 is a spin coater, and the spin-coated coated substrate can be dried under reduced pressure as it is, but such a method is not necessarily suitable for coating and drying a large substrate. .

Furthermore, the reduced-pressure drying processing apparatus 10 includes an exhaust port 18 that discharges gas in order to decompress the decompression chamber 13. The position and number of the exhaust ports 18 are not particularly limited. For example, the exhaust ports 18 can be arranged on the bottom plate surface of the lower chamber 12, the top plate surface of the upper chamber 11, or the side wall surfaces of the upper chamber 11 and the lower chamber 12. . The piping of the exhaust port 18 is connected to a vacuum pump 20 via a valve 19 that controls the exhaust amount. By reducing the pressure by the operation of the vacuum pump 20, the gas in the decompression chamber 13 is discharged and drying under reduced pressure becomes possible. As the valve 19, for example, a variable flow rate valve such as a needle valve is preferably used.
In addition to the type shown in FIG. 1, the stage 15 can employ a structure directly coupled to the lower chamber 12. Furthermore, the bottom plate surface of the lower chamber 12 may also serve as the stage 15. In such a case, the exhaust port 18 is preferably disposed at a position other than the bottom plate surface of the lower chamber 12.

In addition, the reduced pressure drying apparatus 10 in the present embodiment is provided in a pipe branched from the reduced pressure chamber 13 and monitors the detection result by the pressure detector 29 and a pressure detector 29 that measures the pressure in the reduced pressure chamber 13. A control unit 30 that determines a drying end point and an output unit 31 that outputs a determination result by the control unit 30 are provided. As the pressure detector 29, for example, a diaphragm type sensor is used. By using this diaphragm type sensor, it becomes possible to measure the absolute pressure, and it becomes unnecessary to calibrate according to the type of the dry solvent component. Further, it can be made less susceptible to contamination by solvent vapor.
Further, in the present embodiment, a change in pressure in the decompression chamber 13 is used to determine the dry state.

  Here, when the reduced-pressure drying process is finished in a state where the coated substrate is not sufficiently dried, even if the surface is dried to the extent that no pin marks are generated, for example, due to an abnormality in leveling (smoothing) Chromaticity unevenness may occur. Conventionally, taking into account such problems, for example, experience has assumed that the material is sufficiently dry and no abnormality occurs, and the vacuum drying by the vacuum drying apparatus 10 is performed over a sufficient time. However, in such empirical management, drying unevenness may occur due to differences in various conditions such as the state of the reduced-pressure drying processing apparatus 10, and it is necessary to increase the drying condition margin. The increase was serious. Accordingly, as a result of the sharp studies by the applicants and the like, it has been found that the dried state of the coated substrate can be recognized by grasping the pressure state in the reduced-pressure drying processing apparatus 10.

  FIG. 2 is a diagram showing an example of a reduced pressure drying curve when a predetermined coated substrate is dried by the reduced pressure drying processing apparatus 10. The horizontal axis represents time (msec), and the vertical axis represents the logarithmic value (kPa) of pressure. In order to facilitate understanding, a thin line is drawn with respect to the inclination. As a result of a sharp study by the applicants, the inclination 1 from 0 to about 2200 msec and the inclination 3 after about 5000 msec are inclinations determined by the exhaust characteristics of the vacuum pump 20 and have a certain inclination. I found out. On the other hand, the slope 2 from about 2200 to about 5000 msec has been found to be a flat portion (plateau) that appears due to solvent evaporation. The inflection point (first inflection point) between the inclination 1 and inclination 2 coincides with the start of drying on the coated substrate, and the inflection point between the inclination 2 and inclination 3 (second inflection point) is This is consistent with the end of drying of the coated substrate. Note that the inclination 1 and the inclination 3 are not necessarily the same inclination.

FIG. 3 and FIG. 4 are diagrams for explaining the difference in the vacuum drying curve depending on the type of solvent. As in FIG. 2, the horizontal axis represents time (msec) and the vertical axis represents the logarithmic value of pressure (kPa).
FIG. 3 shows a reduced pressure drying curve when the coated substrate coated with a predetermined solvent used for the R (red) resist is dried. In the solvent shown in FIG. 3, the first bending point appears at about 2200 msec, and the second bending point appears at about 8100 msec. FIG. 4 shows a vacuum drying curve when a coated substrate coated with a predetermined solvent used for a Bk (black) resist is dried. In the example shown in FIG. 4, the first bending point appears at about 1900 msec, and the second bending point appears at about 5200 msec. As described above, the time at which the inflection point appears varies depending on the solvent, but it can be understood that the same reduced pressure drying curve can be obtained in the coated substrate coated with each solvent. In addition, these reduced-pressure drying curves may change due to process variations such as solvent application.

  Therefore, in the present embodiment, in view of obtaining such a reduced-pressure drying curve characteristic, a line between the pressure (logarithm) and time during the reduced-pressure drying process detected by the pressure detector 29 in the control unit 30. The figure was drawn, and the second bending point obtained from the inclination was determined as the drying end point of the treated substrate. Then, the control unit 30 controls the valve 19 and the vacuum pump 20 so as to exhaust excessively up to a certain lower pressure value than the drying end point thus determined or for a certain long time. Configured. Depending on the situation, in order to improve the production yield with the end point of drying being grasped, control is performed so that the exhaust is performed up to a constant pressure value higher than the second bending point or for a certain short time. It is also possible to do. This control result by the control unit 30 is notified to the user via an output unit 31 such as a display or a buzzer.

FIG. 5 is a flowchart showing the process of determining the drying end point executed by the control unit 30. First, the control unit 30 detects the pressure for each hour with the pressure detector 29 in a state where the coated substrate is not placed on the stage 15, and measures the pressure change (step 101). Then, a pressure (logarithm) -time diagram is calculated, and the gradient is stored as X in a predetermined memory (step 102). This memory is realized by a predetermined RAM, ROM or the like that constitutes a part of the control unit 30. In addition, if the chamber volume of the decompression chamber 13 formed by the upper chamber 11 and the lower chamber 12 is V and the exhaust speed is S, the slope X is X = 0.434 * S / V.
When this relationship is established and there is a coated substrate, the substantial S becomes small, and the inclination X becomes small.

  Next, the control unit 30 measures the pressure for each predetermined time during the coating substrate drying process when actually performing the drying process (step 103). Then, within a suitable pressure range (for example, 1000 Pa to 100 Pa), a logarithm of the logarithmic value of the pressure taken in every certain time interval is obtained and set as P [i] (step 104). Further, a smoothed number sequence obtained by multiplying [i] by N moving averages is obtained as Q [i] (step 105). Further, a difference sequence of Q [i] is obtained and set as R [i] (= Q [i + 1] −Q [i]) (step 106). This R [i] corresponds to the inclination.

after that,
| R [i] − (X + ΔX) | = e (ΔX is a threshold value equation of inclination change)
Then, R [i] group satisfying e <E (E is a setting error) is obtained (step 107). As a result, two groups corresponding to the drying start point and the drying end point are extracted. Finally, i that minimizes e is calculated, and the processing ends as a drying start point and a drying end point, respectively (step 108).

As described above, the control unit 30 obtains the drying start point and the drying end point for each coated substrate to be placed, and can determine the end of drying for each coated substrate to be placed. The control unit 30 that has determined the end of drying in this way controls the vacuum pump 20 and the valve 19 so as to perform evacuation to a certain lower pressure value than the determined drying end point or for a certain long time. By controlling in this way, it is possible to reliably perform the processing up to the end point of drying, and it is possible to prevent the occurrence of unevenness due to wetting at the time of return pressure and the occurrence of unevenness due to hot plate processing after drying. In addition, troubles in subsequent steps (such as exposure and development) due to an excessive residual solvent can be prevented.
Alternatively, the control unit 30 controls the vacuum pump 20 and the valve 19 so as to perform evacuation up to a certain high pressure value from the determined drying end point or for a certain short time. By controlling in this way, the required and minimum drying time can be achieved, manufacturing tact time can be shortened, and production efficiency can be improved.
Further, the control unit 30 can be configured to notify the user via the output unit 31 that the drying end point has been reached, in addition to the case where the reduced-pressure drying process is automatically performed in this way. . With such a configuration, a user such as a person in charge of manufacturing can quickly recognize the dry state, and for example, the time for proceeding to the next step can be greatly shortened.

  Although the above description has focused on the reduced-pressure drying process of the coated substrate, other well-known processes are also performed as a method for manufacturing the single-wafer coated member. In the manufacturing method of a color filter used for a liquid crystal display, for example, as a single wafer coated substrate, first, for example, a black is formed by patterning a photoresist on a prepared glass substrate with a Cr film and etching Cr by using it as a matrix. There are a matrix process and a resin black matrix process in which a black photoresist is applied on a glass substrate and directly patterned. Thereafter, a red pixel generation step, a green pixel generation step, a blue pixel generation step, and the like are executed as an application step for applying a coating liquid, which is a fluid material, onto the substrate and a reduced-pressure drying treatment step. Thereafter, a protective film is formed, for example, in an overcoat process, and an ITO (conductive film) is formed, for example, in a sputtering process. Then, for example, a photospacer step of applying and patterning a photospacer material is performed. Finally, for example, a visual inspection or the like is performed in an inspection process, and the manufacturing process of the color filter that is the single-wafer application member is completed. The reduced-pressure drying process in the present embodiment includes, for example, each application such as a green pixel generation process, a blue pixel generation process, a black matrix generation process, an overcoat generation process, and a photo spacer generation process in addition to the red pixel generation process. Performed after the process.

  As described above in detail, in this embodiment, for example, in a single-wafer-type coated substrate vacuum drying treatment apparatus that exhausts by a vacuum pump, a diagram of pressure (logarithm) and time at the time of vacuum drying treatment is drawn. The second bending point of the inclination is determined as the drying end point of the processed substrate. This makes it possible to reasonably determine appropriate drying conditions for each coating material and coating condition, and facilitates determination of the drying conditions. As a result, the time for determining the conditions is shortened, and the production operating rate can be dramatically improved. Further, the drying condition margin can be minimized, and the manufacturing tact can be shortened. Furthermore, for example, when the vacuum drying process is completed before the end point of drying, there is a problem that chromaticity unevenness due to leveling abnormality occurs even if the pin is dry to the extent that no pin mark appears. According to the form, by determining the drying conditions based on the decompression curve, it is possible to prevent the occurrence of drying defects due to process fluctuations, improve the manufacturing yield, and improve the quality of the manufactured single wafer coated substrate. It becomes.

  The present invention can be applied to, for example, a method for manufacturing a single-wafer coating member such as a display member, a vacuum drying processing method in the manufacturing method, and a vacuum drying processing apparatus that actually performs vacuum drying processing. .

It is the block diagram which showed the reduced pressure drying processing apparatus to which this Embodiment is applied. It is the figure which showed an example of the reduced-pressure drying curve at the time of drying a predetermined application | coating board | substrate with a reduced pressure drying processing apparatus. It is the figure which showed the vacuum drying curve of the application | coating board | substrate which apply | coated the solvent used for R resist. It is the figure which showed the reduced pressure drying curve of the application | coating board | substrate which apply | coated the solvent used for Bk resist. It is the flowchart which showed the process of the drying end point determination performed with a control part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Depressurization drying processing apparatus, 11 ... Upper chamber, 12 ... Lower chamber, 13 ... Decompression chamber, 14 ... Vacuum seal member, 15 ... Stage, 16 ... Lifting shaft, 17 ... Vacuum seal member, 18 ... Exhaust port, 19 ... Valve, 20 ... Vacuum pump, 29 ... Pressure detector, 30 ... Control part, 31 ... Output part

Claims (11)

An application process for applying a fluid material on a single substrate;
A vacuum drying treatment step of drying the single-wafer coating member coated with the fluid material in the coating step with a vacuum drying treatment apparatus,
The reduced-pressure drying process step monitors the pressure in the reduced-pressure drying apparatus during the reduced-pressure drying process of the single-wafer application member, and grasps the dry state of the single-wafer application member by the change in the monitored pressure. A method for producing a single-wafer application member.   In the vacuum drying treatment step, when a diagram of the pressure and time in the vacuum drying processing apparatus during the vacuum drying treatment of the single-wafer coating member is drawn, the bending of the inclination that would be drawn in the diagram 2. The method for manufacturing a single-wafer application member according to claim 1, wherein the point is determined as a drying end point of the single-wafer application member. ^{2. The} method for producing a single wafer coating member according to claim 1, wherein the substrate of the single wafer coated with the fluid material in the coating step and dried under reduced pressure in the vacuum drying treatment step has an area of 1 m < ² > or more. . A vacuum drying treatment method in which a coating member having a fluid coated on a substrate is vacuum-dried using a vacuum drying treatment apparatus,
A measurement step of measuring the pressure in each time in the reduced-pressure drying apparatus during the drying process of the application member;
An observation step for observing changes in measured pressure over time;
And a determination step of determining a drying end point of the coating member based on the observed change.   5. The reduced-pressure drying method according to claim 4, wherein the determining step determines the inflection point at which the tendency of change with respect to time of the pressure observed in the observation step changes as the drying end point. The observation step draws a diagram of the pressure and time measured by the measurement step,
The reduced-pressure drying method according to claim 4, wherein the determining step determines the second bending point appearing in the slope of the diagram drawn by the observation step as the drying end point.   5. The decompression step according to claim 4, further comprising an excessive exhaust step of exhausting excessively to a pressure value that is constant lower than the end point of drying determined in the determination step, or for a predetermined long time. Drying method.   5. The reduced-pressure drying method according to claim 4, further comprising an exhausting step of exhausting to a certain high pressure value or a certain short time from the drying end point determined by the determining step. . A chamber for sealing the single wafer coated substrate coated with the coating member in a decompression chamber;
A pump for decompressing the decompression chamber;
A pressure detector for detecting the pressure in the decompression chamber;
A reduced-pressure drying processing apparatus comprising: a control unit that observes a change in pressure detected by the pressure detector with respect to time and determines a dry state of the single-wafer coated substrate based on the observed change.   The reduced pressure drying apparatus according to claim 9, wherein a diaphragm sensor is used as the pressure detector. The reduced-pressure drying apparatus according to claim 9, further comprising a stage provided in the chamber and on which a single wafer coated substrate having an area of 1 m ² or more can be placed.

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