JP3920699B2 - Vacuum drying apparatus and coating film forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum dryer that is used when a coated film composed of, for example, a resist film is formed on a semiconductor wafer and can improve the thickness uniformity of the coated film by controlling the flow of coating liquid. <P>SOLUTION: The semiconductor wafer W to which the coating liquid prepared by mixing the component of the coated film with a solvent has been applied in a preceding step is placed on a placing base 41 provided in a closed container 4, and the solvent is vaporized from the liquid applied to the surface of the wafer W by reducing pressure in the container 4 by means of a vacuum pump 46. Then a rectifying plate 5 is provided to face the surface of the wafer W placed on the placing base 41, and the pressure in the container 4 is detected by means of a pressure sensor 55. When the pressure detected by means of the sensor 55 becomes a prescribed value or lower, the rectifying plate 5 is raised from the first position to a second position higher than the first position. Consequently, the film thickness of the coating liquid can be controlled and the in-plane uniformity of the film thickness is improved, because the outwardly expanding flow of the coating liquid is controlled between the wafer W and the plate 5. <P>COPYRIGHT: (C)2003,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a coating film formed on a substrate such as a semiconductor wafer or an LCD substrate (glass substrate for liquid crystal display) by applying a coating solution, for example, a resist solution obtained by mixing components of the coating film with a solvent. The present invention relates to a reduced-pressure drying apparatus that volatilizes a solvent from a coating solution and a coating film forming method.
[0002]
[Prior art]
In the manufacturing process of semiconductor devices and LCDs, resist processing is performed on a substrate to be processed by a technique called photolithography. In this technique, for example, a resist solution is applied to a semiconductor wafer (hereinafter referred to as a wafer), a liquid film is formed on the surface, the resist film is exposed using a photomask, and then a development process is performed to obtain a desired pattern. Is performed by a series of steps.
[0003]
As one of the above-mentioned resist solution coating methods, a coating solution (resist solution) obtained by mixing a resist and a solvent, which are components of a coating film, is formed above the wafer W, for example, as shown in FIG. While the provided nozzle 10 is reciprocated in the X direction and the wafer W is intermittently fed in the Y direction, the coating liquid is discharged from the nozzle 10 onto the surface of the wafer W, and the coating liquid is applied in a so-called one-stroke manner. There is a way. In the figure, reference numeral 12 denotes a mask that covers an area other than the circuit formation area 11 of the wafer W.
[0004]
As the solvent contained in the coating solution, a solvent having low volatility is used, or the solvent is quickly removed from the surface of the wafer W to ensure the film thickness uniformity of the coating film. In carrying out the method, it is considered preferable to apply the coating liquid onto the wafer W and immediately carry it into the reduced pressure drying unit to perform the reduced pressure drying. FIG. 31 is a view showing a conventional vacuum drying unit. In the figure, reference numeral 13 denotes a sealed container composed of a lid body 14 and a mounting portion 15, and an opening 14 a is formed in the ceiling portion of the lid body 14. The opening 14a communicates with the vacuum pump 16 through the exhaust pipe 14b so that the inside of the sealed container 13 can be depressurized. In such an apparatus, the wafer W is placed on the placement unit 15, the wafer W is heated by a heating means (not shown), the vacuum pump 16 is operated, and the inside of the sealed container 11 is depressurized. For example, a solvent such as a thinner solution is volatilized (dried) remaining on the surface, and the volatilized solvent is sucked to the vacuum pump 16 side so that the resist component in the coating solution remains on the surface of the wafer W.
[0005]
[Problems to be solved by the invention]
By the way, the state of the coating liquid 17 on the surface of the wafer W when it is transported to the vacuum drying unit is, for example, as shown in FIG. Are rounded due to the surface tension of the coating liquid itself. For this reason, as shown by a dotted line in FIG. 29, it is considered to provide a current plate 18 on the upper side of the wafer W placed on the placement unit 15 so as to face the wafer W. When the current plate 18 is thus provided and the inside of the hermetic container 13 is depressurized, an air flow spreading outside is formed between the current plate 18 and the wafer W, whereby the coating liquid spreads toward the peripheral side on the wafer W surface. Go.
[0006]
For this reason, when the current plate 18 is provided and vacuum drying is performed, as shown in FIG. 32B, the coating liquid is drawn toward the peripheral side, and the thickness of the coating film in the peripheral region becomes extremely large. If the peripheral region of the coating film is rounded or raised as described above, the peripheral region of the coating film is greatly different from the central portion, and thus the peripheral region cannot be used as a circuit formation region. Here, there is a demand to increase the chip acquisition rate per wafer W by making the circuit formation region as wide as possible, and in the coating film formed on the surface of the wafer W, the control of the film thickness between the central portion and the peripheral region is performed. It is a serious issue.
[0007]
The present invention has been made based on such circumstances, and the object thereof is to control the film thickness of the coating film at the time of drying under reduced pressure in a reduced-pressure drying apparatus for a substrate provided in the coating film forming apparatus, for example. It is to provide a technique capable of ensuring in-plane uniformity.
[0008]
[Means for Solving the Problems]
  The reduced-pressure drying apparatus according to the present invention includes a hermetically sealed container provided with a placement portion for placing a substrate coated with a coating solution obtained by mixing a component of a coating film and a solvent,
  A vacuum evacuation means connected to the sealed container via an exhaust path, and setting the inside of the sealed container in a reduced pressure atmosphere to volatilize the solvent from the coating solution on the substrate;
  A rectifying member provided to face the surface of the substrate placed on the placement portion;
  A rectifying member lifting mechanism for lifting and lowering the rectifying member;
A pressure detector for detecting the pressure in the sealed container;
  The inside of the closed container is evacuated to discharge air, thereby lowering the pressure with a steep slope, and then gradually lowering the pressure by maintaining the pressure slightly higher than the pressure at which the solvent reaches the boiling point until the evaporation of the solvent is completed. When the pressure detection value of the pressure detection unit becomes smaller than a preset set pressure while the pressure is gradually lowered, the rectifying member is A control unit for changing from a position of 1 to a second position higher than the first position;It is provided with.
A reduced-pressure drying apparatus according to another invention is a sealed container in which a mounting portion for mounting a substrate coated with a coating liquid obtained by mixing a component of a coating film and a solvent is provided;
A vacuum evacuation means connected to the sealed container via an exhaust path, and setting the inside of the sealed container in a reduced pressure atmosphere to volatilize the solvent from the coating solution on the substrate;
A rectifying member provided to face the surface of the substrate placed on the placement portion;
A rectifying member lifting mechanism for lifting and lowering the rectifying member;
A film thickness measuring means for measuring the thickness of the coating film formed on the substrate surface,
  While the inside of the sealed container is in a reduced pressure atmosphere and the solvent is volatilized from the coating solution on the substrate, the rectifying member is moved up and down by the rectifying member lifting mechanism based on the measured value from the film thickness measuring means, It is characterized by changing the height position.
[0009]
In such a configuration, an exhaust flow from the center toward the outside is formed between the rectifying member and the substrate during the decompression drying process, but the height position of the rectification member is changed during the decompression drying process. Thus, the liquid flow of the coating liquid is controlled, and thereby the film thickness of the coating film on the substrate surface can be controlled. For this reason, roundness and swelling of the coating liquid in the peripheral region of the substrate are suppressed, the film thicknesses of the central portion and the peripheral region of the coating film are made uniform, and the film thickness uniformity can be improved.
[0013]
  furtherOther inventionsApplying a coating solution obtained by mixing the components of the coating film and the solvent onto the substrate surface;
  Placing the substrate coated with the coating solution in a sealed container;
  The inside of the closed container is evacuated to discharge air, thereby lowering the pressure with a steep slope, and then gradually lowering the pressure by maintaining the pressure slightly higher than the pressure at which the solvent reaches the boiling point until the evaporation of the solvent is completed. Process,
Until the pressure set in the pressure region in the step of gradually lowering the pressure,Providing a rectifying member at a first position on the upper side of the substrate placed in the sealed container so as to face the substrate;
When it becomes smaller than the set pressure,And a second step of changing the rectifying member to a second position higher than the first position so as to face the substrate.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
First, the overall configuration of a coating film forming apparatus incorporating the reduced pressure drying apparatus of the present invention will be briefly described with reference to FIGS. In the figure, reference numeral 21 denotes a cassette station, for example, a delivery for transferring the wafer W between the cassette placement unit 22 for placing a cassette C containing 25 wafers W and the placed cassette C. An arm 23 is provided, and a processing unit S <b> 1 is connected to the back side of the transfer arm 23. A main transport means 24 is provided at the center of the processing section S1, and a coating / developing system unit 25 is provided with a plurality of coating units 25A and developing units 25B on the right side, for example. However, shelf units U1, U2, and U3 in which heating / cooling units and the like are stacked in multiple stages are arranged on the left side, front side, and back side, respectively.
[0015]
The shelf units U1, U2, and U3 are configured by combining various units for performing pre-processing and post-processing of the coating unit 25A, and the combinations are represented by, for example, the shelf units U2 and U3 in FIG. As shown in the drawing, the wafer W having the coating solution coated on the surface thereof by the coating unit 25A is dried in a reduced pressure atmosphere, and the reduced pressure drying unit 26 that volatilizes the solvent contained in the coating solution, and the wafer W is heated (baked). A heating unit that cools the wafer W, a hydrophobic treatment unit, and the like. As for the shelf units U2 and U3, a delivery unit including a delivery table for delivering the wafer W is also incorporated. Further, the main transport means 24 described above is configured to be movable up and down and back and forth and to rotate around the vertical axis, for example, each unit constituting the coating unit 25A, the developing unit 25B, and the shelf units U1, U2, and U3. It is possible to transfer the wafer W between them.
[0016]
An exposure apparatus S3 is connected to the back side of the processing unit S1 through an interface unit S2. The interface unit S2 transfers the wafer W between the processing unit S1 and the exposure apparatus S3 by a transfer arm 27 configured to be movable up and down, movable left and right, back and forth, and rotatable about a vertical axis. It is.
[0017]
The flow of the wafer W in such a coating film forming apparatus will be briefly described. First, when the cassette C is loaded into the cassette station 21, the wafer W is taken out by the transfer arm 23. Then, the wafer W is transferred from the transfer arm 23 to the main transfer means 24 via the transfer unit in the shelf unit U2, and after being subjected to hydrophobic treatment in the hydrophobic unit, it is transferred into the coating unit 25A. Here, a resist solution which is a coating solution is applied. Next, the wafer W coated with the coating liquid is transferred to the vacuum drying unit 26 by the main transfer means 24, where the solvent contained in the coating liquid on the surface of the wafer W is evaporated and dried by a predetermined method. The wafer W is unloaded by the main transfer means 24 through a process in the reverse order to when it is loaded into the reduced-pressure drying unit 26, and is transferred to the cooling unit as the next process. Thereafter, the image is sent to the exposure apparatus S3 through the interface unit S2 and the transfer arm 27, where exposure is performed through a mask corresponding to the pattern. The wafer W after the exposure process is transferred to the processing unit S1 through the reverse path, sent to the development unit 25B through the cooling unit, and subjected to the development process, thereby forming a resist mask. Thereafter, the wafer W is returned to the original cassette C through the reverse path.
[0018]
Next, the coating unit 25 will be described with reference to FIGS. 4 and 5. Here, the casing that forms the exterior of the coating unit 25 is omitted, but in this casing (not shown), for example, a hollow case in which an opening (not shown) for loading and unloading the wafer W is formed on the side. A body 30 is provided, and a substrate holding part 31 for holding the wafer W by vacuum suction from the back side and holding it horizontally, and supporting the substrate holding part 31 from the lower side, as well as raising and lowering the substrate holding part 31. An elevating mechanism 32 is provided. A slit 33 extending in the X direction is formed in the ceiling portion of the case body 30, and above this slit 33, a nozzle 34 for supplying a resist solution, which is a coating solution, is a discharge hole 34 a at the lower end. Is configured to be movable in the X direction by the drive unit 35 in a state of protruding into the case body 30 through the slit 33.
[0019]
On the other hand, the substrate holding unit 31 and the lifting mechanism 32 are integrated with a flat plate-like support 36 provided on the lower side of the wafer W held by the substrate holding unit 31 so as to face the back side of the wafer W. It is configured. For example, two rails 37a extending in the Y direction are disposed on the bottom surface of the support 36, and a ball screw 37b is provided in the vicinity of the bottom surface in parallel with the rail 37a. By rotating the ball screw 37b, the support 36 is guided by the rail 37a and moves in the Y direction.
[0020]
In such a coating unit 25 </ b> A, the wafer W carried into the unit 25 </ b> A by the main transfer unit 24 is attracted on the back side by the substrate holding unit 31 and is held substantially horizontally. Then, after positioning the nozzle 34 above the wafer W, the nozzle 34 is moved in the X direction while discharging the coating liquid from the nozzle 34, while the wafer W is intermittently fed in the Y direction by the support 36, and thus in the manner of one-stroke writing. A coating solution is applied.
[0021]
Next, an embodiment of the reduced pressure drying unit 26 constituting the reduced pressure drying apparatus according to the present invention will be described with reference to FIG. In the figure, reference numeral 41 denotes a mounting portion made of, for example, an aluminum material for mounting the wafer W. The wafer W is slightly lifted from the surface of the mounting portion 41 by the support pins 41a slightly protruding from the mounting portion. A lid 42 made of, for example, an aluminum material is provided at the top of the mounting portion 41. The lid 42 can be moved up and down by the action of an elevating mechanism 43 including a holding arm 43a, a driving unit 43b, and the like. When the lid 42 is lowered, the lid 42 is hermetically sealed via the peripheral edge of the mounting unit 41 and the O-ring 40 which is a sealing material. The sealed container 4 is configured such that the atmosphere in which the wafer W is placed is sealed.
[0022]
In the vicinity of the surface of the mounting portion 41, a heater H that constitutes a heating means configured by, for example, a resistance heating body for heating the wafer W at the time of drying under reduced pressure is embedded, and inside the mounting portion 41, Three lift pins 44 are provided so as to be able to pass the wafer W to and from the main transfer means 24, and the lift pins 44 are provided through a first lift plate 44a, for example, a first lift and lower such as an air cylinder. It can be moved up and down by the portion 44b.
[0023]
An opening 45a is formed in the ceiling 42a of the lid 42 so that the atmosphere in the sealed container 4 can be sucked, and an exhaust pipe 45 forming an exhaust path made of, for example, stainless steel is connected to the opening 45a. The other end side of the exhaust pipe 45 passes through a housing (not shown) of the reduced pressure drying unit 26 and a housing (not shown) of the processing unit S1, and opens and closes a valve to a vacuum pump 46 that is a vacuum exhaust means provided in a clean room, for example. Connected via V1.
[0024]
Further, in the space facing the wafer W in the lid 42, the plate 42 is opposed to the wafer W placed on the placement portion 41 and has a gap between the ceiling 42 a and the side wall 42 b of the lid 42. A rectifying plate 5 that is a rectifying member of the body is provided, and the rectifying plate 5 is, for example, a plurality of substantially vertical plural, for example, three provided so as to penetrate the mounting portion 41 on the outer side of the wafer W, for example. The support rod 51 and the connection member 52 are connected. The support bar 51 can be moved up and down by a rectifying plate elevating mechanism 53 that constitutes a rectifying member elevating mechanism including a second elevating plate 53a and a second elevating part 53b such as an air cylinder. Is configured to be movable up and down above the wafer W so that the height position of the wafer W can be changed.
[0025]
At this time, in order to prevent the atmosphere in which the wafer W is placed from communicating with the atmosphere side through the through holes 47a of the lift pins 44 and the through holes 54a of the support rod 51, the peripheral portions of the first and second elevating plates 44a and 53a Bellows 47b and 44b are provided between the mounting portion 41 and the mounting portion 41, respectively. By providing the current plate 5 in this manner, a uniform exhaust flow is formed along the inner wall surface of the lid 42 during drying under reduced pressure.
[0026]
Further, the sealed container 4 is provided with a pressure sensor 55 that forms a pressure detection unit for detecting the pressure in the container 4, for example, on the inner wall of the lid 42, and based on the detection value of the pressure sensor 55. The controller 56 is configured so that the height position of the rectifying plate 5 can be changed via the rectifying plate lifting mechanism 53.
[0027]
Next, a vacuum drying method performed in the vacuum drying unit 26 will be described. First, the wafer W on which the resist solution, which is a coating solution, is applied in the previous process is transferred to the reduced pressure drying unit 26 by the main transfer means 24. In loading the wafer W into the vacuum drying unit 26, first, the arm (not shown) of the main transfer means 24 enters the upper side of the mounting portion 41 with the lid 42 and the rectifying plate 5 raised, and the lift pins 44 are raised. After the wafer W is received from the arm, the lift pins 44 are lowered.
[0028]
Thereafter, the current plate 5 is lowered to an initial position, for example, the distance between the front surface of the wafer W and the rear surface of the current plate 5 is 5 mm, and then the lid 42 is lowered to form the sealed container 4. 5 is once lowered to a position of 3 mm, then the on-off valve V1 is opened, and the vacuum pump 46 starts depressurization. Next, the current plate 5 is lowered to a first position, for example, a position where the distance between the front surface of the wafer W and the rear surface of the current plate 5 is 1 mm, so that the first distance (gap) is formed between the front surface of the wafer W and the rear surface of the current plate. The pressure is reduced for a predetermined time.
[0029]
Here, the coating liquid (resist liquid) applied to the surface of the wafer W is a mixture of a resist film component that is a coating film and a solvent such as thinner liquid or moisture, but the inside of the sealed container 4 is decompressed. When placed in an atmosphere, the solvent and moisture of the coating solution are volatilized and sucked into the exhaust pipe 45 through the opening 45a. At this time, the exhaust flow in the sealed container 4 is formed so as to bypass the rectifying plate 5, so that the solvent vapor volatilized from the wafer W hits the rectifying plate 5 and changes its direction outward, along with this exhaust flow. It spreads uniformly in the radial direction toward the opening 45a.
[0030]
As described above, an airflow is generated between the wafer W and the rectifying plate 5 from the center side to the outer side of the wafer W, and the airflow becomes stronger as the gap between the rectifying plate 5 and the wafer W is smaller. , It becomes weaker as the gap becomes larger. Therefore, when the gap between the rectifying plate 5 and the wafer W is reduced to 1 mm and the pressure is reduced, the coating liquid spreads due to a strong air current spreading outside the rectifying plate 5 and the wafer W, and reaches the peripheral region of the wafer W. The coating solution is sufficiently distributed. In this way, when the coating liquid is spread to the peripheral region of the wafer W in order to suppress the roundness of the coating film in the peripheral region of the wafer W, the rectifying plate 5 is moved from the first position to the second position higher than the first position at a predetermined timing. For example, the distance between the front surface of the wafer W and the back surface of the rectifying plate 5 is raised to a position of 5 mm, so that the second distance (gap) between the front surface of the wafer W and the back surface of the rectifying plate 5 is larger than the first distance. Continue drying under reduced pressure for a predetermined time.
[0031]
By doing so, the gap between the current plate 5 and the wafer W is increased and the air flow toward the outer side is weakened, so that the liquid flow of the coating liquid is suppressed. For this reason, it is prevented that the thickness of the coating film in the peripheral region of the wafer W becomes high, and the in-plane uniformity of the thickness of the coating film is improved. After drying under reduced pressure in this manner, the coating film is dried by evaporating the solvent and moisture from the coating solution on the surface of the wafer W, and then sealed by, for example, supplying air into the sealed container 4 by an air supply means (not shown). The inside of the container 4 is returned from the reduced pressure state to the normal pressure, the lid 42 and the current plate 5 are raised, the lift pins 44 are raised, and the wafer W is delivered to the main transfer means 24.
[0032]
As described above, in this embodiment, by changing the height position of the rectifying plate 5 during the reduced-pressure drying process, the size of the gap between the rectifying plate 5 and the wafer W is changed. The timing of changing the height position of the rectifying plate 5 is determined based on the pressure in the hermetic container 4 and is controlled by the control unit. The height position of the current plate 5 is changed via 56.
[0033]
That is, when the inside of the sealed container 4 is depressurized, the pressure in the container 4 changes like a pressure curve shown in FIG. That is, the air in the container 4 is discharged from time 0 to time t1, and the inside of the container 4 is depressurized with a steep slope from the pressure P0 to P1. Subsequently, time t1 is a time when the thinner, which is a solvent, starts to volatilize from the coating solution on the surface of the wafer W, and the thinner is volatilized continuously from time t1 to time t3. The pressure is gradually reduced from P1 to P3. Next, time t3 is when the evaporation of water contained in the coating liquid on the surface of the wafer W starts, and from time t3 to time t4, the thinner liquid remaining in the coating liquid and the water are in a state of evaporating. At this time, the pressure in the container 4 is reduced again with a steep slope from P3 to P4.
[0034]
Here, the thinner liquid is volatilized (evaporated) even in a state where the inside of the container 4 is not depressurized when the temperature in the sealed container 4 is constant, but if the pressure in the container 4 is lowered at once, it immediately reaches the boiling point, It becomes a state of volatilizing from the inside of the thinner liquid. However, when volatilizing from the thinner liquid in this way, the coating film becomes rough. For this reason, in the above-described embodiment, the exhaust amount by the vacuum pump 46 is determined so that the pressure in the container 4 is slightly lowered. Thus, if the exhaust speed by the vacuum pump 46 is set a little small, the thinner liquid volatilizes violently just before the boiling point, and the pressure in the container 4 is changed from the pressure P1 due to the balance between the presence of the volatilized gas and the exhaust speed. The pressure is gently inclined downward like the pressure P3. Thus, the “state in which the thinner liquid volatilizes violently” is referred to as “thinner liquid volatilization” in the present invention, and this state includes the boiling point and the state before the boiling point.
[0035]
The state of the coating liquid on the surface of the wafer W is affected by the fluidity of the coating liquid due to the volatilization of the thinner, which is a solvent. In addition, the amount of solvent is large at the initial stage of volatilization, and the fluidity increases. It is necessary to change the height position of 5. Specifically, the height position of the rectifying plate 5 is from time 0 to time t1 when the air in the container 4 is discharged and from time t3 to time t4 when the moisture evaporates from the coating liquid on the surface of the wafer W. Any position is acceptable, and it is required to control the height position of the rectifying plate 5 between the time t1 and the time t3 when the thinner liquid as the solvent is volatilized from the coating liquid.
[0036]
Further, during the volatilization of the solvent, it is necessary to increase the fluidity of the coating liquid at first and sufficiently spread the coating liquid to the peripheral area of the wafer W. Thereafter, the fluidity of the coating liquid is suppressed and the peripheral area of the wafer W is suppressed. It is necessary to prevent the coating liquid height from becoming too large. Here, the fluidity of the coating liquid changes depending on the magnitude of the airflow generated between the wafer W and the rectifying plate 5, and the airflow is reduced when the gap between the wafer W and the rectifying plate 5 is small as described above. When the gap is large, the airflow is weakened.
[0037]
At this time, as described above, the pressure in the container 4 gradually decreases from P1 to P3 from time t1 to time t3, and therefore when the pressure reaches the preset pressure P2 (time t2) obtained in advance. The rectifying plate 5 is raised from the first position to the second position. In addition, before the time t1 and after the time t3, the height of the current plate does not affect the coating film and may be set to any height. However, in this example, the time for moving the current plate 5 is saved. The first position is set from time t1 to time t2, and the second position is set from time t2 to time t4. Here, the set pressure P2, the first position (first gap), and the second position (second gap) are the size of the wafer W, the processing conditions such as the temperature and pressure in the sealed container 4, and the application. It is appropriately selected depending on the components of the liquid.
[0038]
According to the above-described embodiment, the flow position of the coating liquid is controlled by changing the height position of the rectifying plate 5 and changing the size of the gap between the rectifying plate 5 and the wafer W during the vacuum drying process. Therefore, the film thickness of the coating film on the surface of the wafer W can be controlled, and the roundness and swelling of the coating liquid in the peripheral area of the wafer W can be suppressed, and the film between the central portion and the peripheral area of the coating film can be suppressed. The thickness is uniform, and the uniformity of the film thickness can be improved. As a result, chips can be manufactured up to the vicinity of the outer peripheral edge of the wafer W (a circuit forming region), and the chip acquisition rate per wafer W can be improved. Further, by improving the uniformity of the coating film thickness, the film thickness can be stabilized, the device can be stably produced, and the throughput can be increased.
[0039]
At this time, since the height of the rectifying plate 5 is controlled based on the pressure in the sealed container 4, the timing of changing the height position of the rectifying plate 5 is highly reliable and always stable. Thus, processing with high uniformity of the coating film thickness can be performed, so that high throughput can be obtained.
[0040]
In this embodiment, after the wafer W is placed on the placement portion 41 and the lid 42 is lowered to form the sealed container 4, the flow straightening plate 5 is first lowered to the first position, and then the open / close valve is opened. V1 is opened, pressure reduction is started by the vacuum pump 46, and the pressure is reduced for a predetermined time. Next, when the pressure in the container 4 reaches the pressure P2, the rectifying plate 5 may be raised from the first position to the second position, and the vacuum drying may be continued for a predetermined time.
[0041]
Subsequently, other embodiments of the reduced pressure drying unit 26 will be described individually. In the following drawings, the same members are denoted by the same reference numerals. Further, the following examples may be combined with the above-described reduced-pressure drying unit 26, or other embodiments may be combined with each other.
[0042]
In the example of FIG. 8, instead of controlling the height of the rectifying plate 5 based on the pressure in the sealed container 4, the film thickness of the coating liquid A on the surface of the wafer W is measured by, for example, a film thickness measuring means using CCD or light. The thickness of the current plate 5 is controlled based on the measurement by the film thickness sensor 57. In this case, for example, the film thickness of the central portion and the peripheral portion of the coating liquid on the surface of the wafer W is measured, the difference between these film thicknesses is calculated, and when this value becomes a predetermined value or less, Control is made to raise the height from the first position to the second position. Even in this case, high uniformity of the thickness of the coating film can be secured stably, and high throughput can be obtained.
[0043]
Further, the volatilization time of the solvent may be controlled as follows. In the example shown in FIG. 9, a pressure adjusting unit 58 including, for example, a pressure adjusting valve is provided between the exhaust pipe 45 and the vacuum pump 46, and the pressure inside the sealed container 4 is detected by the pressure sensor 55, and based on this detected value. Then, the control unit 56 adjusts the pressure adjusting unit 58 to control the exhaust amount (exhaust speed) in the sealed container 4, thereby adjusting the evaporation time of the solvent of the coating solution. For example, when a pressure adjusting valve is used as the pressure adjusting unit 58, the displacement can be controlled by adjusting the opening of the valve. In this case, as shown in FIG. 10, even if the displacement is changed, the slope of the pressure curve from time t1 to time t3 does not change, but if the exhaust speed is increased or decreased between time t1 and time t3. The solvent volatilization time can be adjusted. That is, when the exhaust amount is increased, the solvent evaporation time is shortened as shown by a one-dot chain line in the figure, and when the exhaust amount is reduced, the solvent evaporation time is increased as shown by a dotted line in the figure.
[0044]
Here, for example, when a coating liquid using a thinner that is rapidly volatile as a solvent is applied to the surface of the wafer W, the spreading speed of the coating liquid is fast, so the diffusion state of the coating liquid is controlled by controlling the height position of the rectifying plate 5. Although it may be difficult to control accurately, as shown in this example, if the evaporation time of the solvent of the coating solution is increased, the spreading rate of the coating solution can be reduced as a result. Even for a coating solution using a solvent as a solvent, the diffusion state of the coating solution can be sufficiently controlled by controlling the height position of the rectifying plate 5, and the film thickness of the coating solution can be easily controlled. it can.
[0045]
Next, the example shown in FIG. 11 has a configuration in which heating means for heating the wafer W at the time t3 is provided in the closed vessel 4 in the pressure curve in the closed vessel 4 shown in FIG. Yes, the heating means may be provided in any place in the sealed container 4 such as the inside of the mounting portion 41 or the lid body 42. Is provided inside.
[0046]
As described above, in the pressure curve in the sealed container 4 shown in FIG. 7, when the wafer W is heated at the time t3, the moisture contained in the thinner liquid or the coating liquid remaining in the coating liquid on the surface of the wafer W due to the heating. The evaporation rate increases. Therefore, for example, even when a coating liquid using a thinner liquid as a solvent is applied to the surface of the wafer W and the time required for volatilization of all the thinner liquid is long, the thinner is heated by heating. Is volatilized quickly. Therefore, the time required for the reduced-pressure drying process is shortened compared to the case where heating is not performed. The reason for starting heating at time t3 is that in the process of controlling the film thickness of the coating liquid from time t1 to time t3, the film thickness can be controlled more accurately when the solvent volatilization rate is lower. It is.
[0047]
In this case, during heating by the heating means 59, the decompression in the sealed container 4 may or may not be stopped. The timing for turning on the heating means 59 may be determined based on the detected value of the pressure in the sealed container 4 or may be determined based on the detected value of the film thickness of the coating liquid. Further, the heating of the wafer W and the adjustment of the exhaust amount in the hermetic container 4 as shown in FIG. 9 are performed in combination, the time from time t1 to time t3 is lengthened to accurately control the film thickness, and after time t3 The total processing time required for the reduced-pressure drying step may be adjusted by shortening the time.
[0048]
In order to make the spread of the coating solution uniform in the plane of the wafer W as described above, it is important to arrange the rectifying plate 5 so as to be parallel to the wafer W. An example of a mechanism provided so as to be parallel to W will be described with reference to FIGS.
[0049]
In FIG. 12, reference numeral 60 denotes a suspension support part for suspending and holding the current plate 5 by the lid body 42. The support part 60 is provided at, for example, three places of the current plate 5 as shown in FIG. The rectifying plate 5 is suspended and supported by, for example, three support portions 60. As shown in FIG. 14, the support portion 60 includes a substantially vertical holding rod 61, a flange portion 62 provided on the upper end side of the holding rod 61, and a spring portion 63 wound around the holding rod 61. The lower end side of the holding rod 61 is joined to the surface of the rectifying plate 5 facing the lid 42 by the spherical joint portion 64.
[0050]
The inner wall (ceiling part) 42a of the lid 42 that faces the rectifying plate 5 is formed with a recess 42b that can move the flange 62 at a position that faces the holding rod 61. The opening 42c is narrowed so that the holding rod 61 can pass but the flange 62 cannot pass. As a result, the holding rod 61 can be raised and lowered by the height of the recess 42b in a state in which the current plate 5 is suspended and held when the current plate 5 is lifted and lowered by a current plate lifting mechanism described later.
[0051]
Next, the rectifying plate elevating mechanism 65 constituting the rectifying member elevating mechanism will be described. First, as shown in FIGS. 12 and 15, the current plate 5 includes a plurality of, for example, three foot portions 50 at a position on the outer side of the wafer W placed on the placement portion 41. The foot part 50 is formed so as to extend substantially vertically to the inside from the surface of the mounting part 41 on the lower side, and the lower end side thereof is connected to a lifting rod described later.
[0052]
As shown in FIGS. 12 and 15, the rectifying plate elevating mechanism 65 includes a plurality of, for example, three elevating bars 66 that press the rectifying plate 5 from the back side via the foot portions 50, and the lower end sides of all the elevating bars 66. And an elevating plate 67 connected to the elevating unit 67 and an elevating unit 68 for elevating the elevating plate 67. The elevating bar 66 is provided so as to be raised and lowered at a position corresponding to the foot portion 50 of the rectifying plate 5, and is raised and lowered by the elevating bar 66 when the elevating bar 66 is raised and lowered by the elevating plate 67. The leg portion 50, the elevating bar 66, and the elevating plate 67 of the rectifying plate 5 are configured so that the rectifying plate 5 can maintain high parallelism with the wafer W placed on the placing portion 41.
[0053]
A vent hole 66a having a hole diameter of, for example, 2 mm passes through the inside of the elevating bar 66, and a region in the vicinity of the upper end side of the elevating bar 66 is formed so as to be inserted into the lower end side of the foot portion 50 of the rectifying plate 5. ing. The other end side of the lifting / lowering bar 66 not in contact with the rectifying plate 5 is connected to the first exhaust means 66b via the opening / closing valve V2. Reference numeral 66 c denotes a through hole of the elevating rod 66, and an O-ring 66 d that forms a seal member is provided between the through hole 66 c and the elevating rod 66. In addition, a bellows 66e is provided between the mounting portion 41 around the lifting rod 66 and the lifting plate 67 in order to prevent the inside of the sealed container 4 from communicating with the atmosphere side through the through hole 66c.
[0054]
As shown in FIG. 12, the elevating part 68 includes a substantially vertical ball screw 68a, a support part 68b connected to one end side of the elevating plate 67, and a motor M1 for rotating the ball screw 68a. The motor M1 rotates the ball screw 68a, so that the support portion 68b moves up and down along the ball screw 68a. As a result, the rectifying plate 5 is moved up and down at an accurate height via the lifting plate 67 and the lifting rod 66. The rectifying plate 5 moved up and down by the rod 66 is configured to be moved up and down while maintaining high parallelism with respect to the wafer W placed on the placement unit 41.
[0055]
Further, in the sealed container 4 of this example, O-rings 69a and 69b forming two sealing members having different inner diameters are provided at a connection portion between the mounting portion 41 and the lid body 42, and between these O-rings 69a and 69b. A groove portion 41b is formed, and this groove portion 41b is connected to the second exhaust means 69c via an on-off valve V3 as shown in FIG.
[0056]
In such a configuration, the rectifying plate 5 is suspended and supported by the support portion 60 by the lid body 42 while being in contact with the lifting mechanism 65 via the foot portion 50, and the rectifying plate 5 is supported by the lid body 42. Ascending and descending When the height position of the rectifying plate 5 is changed during the reduced pressure drying process, the rectifying plate 5 is pressed from the back side through the foot 50 by the elevating bar 66 of the rectifying plate elevating mechanism 65. In this case, for example, in the above-described example, the height of the rectifying plate 5 is changed between the first position 1 mm above the wafer W surface and the second position 5 mm above the wafer W surface during the decompression process. First, when arranged at the first position, the tip end side of the lifting / lowering rod 66 and the foot 50 of the rectifying plate 5 are brought into contact with each other, and the interior of the lifting / lowering rod 66 is opened by the first exhaust means 66b by opening the opening / closing valve V2. Keep sucked.
[0057]
As a result, the rectifying plate 5 and the lifting / lowering rod 66 come into contact with each other inside the mounting portion 41, so that particles generated in the vicinity of the connecting portion between the foot portion 50 of the rectifying plate 5 and the lifting / lowering rod 66 at the time of raising and lowering are contained in the container 4. The influence on the processing in the inside is small. Further, particles generated in the vicinity of the connecting portion due to the suction of the connecting portion are discharged through the inside of the lifting / lowering rod 66, so that particle contamination can be further prevented. At this time, the rectifying plate 5 and the lifting / lowering rod 66 may be configured to be in direct contact with each other. Become.
[0058]
Further, the parallelism of the rectifying plate 5 is determined by the three lifting rods 66, and the rectifying plate 5 itself is suspended and supported by the lid portion 42, so that a slight inclination occurs in the rectifying plate 5 when it is raised and lowered. There is a case. However, since the rectifying plate 5 and the holding rod 61 are connected by the spherical joint part 64, the inclination of the rectifying plate 5 is absorbed by the spherical joint part 64, and the rectifying plate 5 moved up and down by the elevating bar 66 is mounted. The wafer W placed on the placement unit 41 is moved up and down while maintaining high parallelism. For this reason, the spreading method of the coating liquid on the surface of the wafer W becomes uniform, and uniformity with a higher film thickness can be ensured.
[0059]
Further, in this example, double O-rings 69a and 69b are provided, and a vacuum drying process is performed while the opening / closing valve V3 is opened and suctioned by the second exhaust means 69c therebetween. And the lid 42 are more adsorbed, and when the inside of the sealed container 4 is evacuated by the vacuum pump 46, it is possible to prevent outside air from entering the container 4 from between the mounting portion 41 and the lid 42. it can.
[0060]
In the reduced pressure drying unit 26 of the present invention, the rectifying plate lifting mechanism that forms the rectifying member lifting mechanism may be configured as shown in FIG. In FIG. 16, reference numeral 71 denotes a substantially horizontal ball screw, and 72 denotes a support portion. The support portion 72 moves in the horizontal direction along the ball screw 71 by rotating the ball screw 71 by the motor M2. .
[0061]
On the other hand, a joint connecting portion 73 is provided on the back surface side of the second lifting plate indicated by 53a in the figure. The joint connecting portion 73 and the support portion 72 are provided at both ends of the long plate-like joint portion 74. The rotary shafts 75a and 75b are connected to each other. As a result, when the support portion 72 is at a position away from the joint connection portion 73, the length direction of the joint portion 74 is positioned near horizontal, and the current plate 5 is disposed at a position close to the wafer W. When the ball screw 71 is rotated to move the support portion 72 to a position close to the joint connection portion 73, the length direction of the joint portion 73 gradually becomes nearly vertical, and the current plate 5 is moved from the wafer W. It rises so that it is separated (the height position becomes higher). As described above, in this example, the height position of the rectifying plate 5 is appropriately determined by adjusting the length in the length direction of the joint portion 74 and the angle between the length direction of the joint portion 74 and the wafer W. The
[0062]
In such a configuration, a mechanism in which the support portion 72 moves with high precision in the horizontal direction by the ball screw 71 and a mechanism in which the support portion 72 and the second lifting plate 53a are connected by the joint portion 74 are combined and supported. Since the height position of the rectifying plate 5 is changed via the joint portion 74 by moving the portion 72, when the height of the rectifying plate 5 is changed, the rotational speed of the ball screw 71 is reduced at the initial stage. Thus, the height of the current plate 5 can be changed gently. For this reason, since the disturbance of the airflow when the solvent contained in the coating liquid on the surface of the wafer W is evaporated can be suppressed, the uniformity of the film thickness of the coating film can be further improved.
[0063]
Next, still another embodiment of the reduced pressure drying unit 26 of the present invention will be described with reference to FIGS. In this embodiment, a member that contacts the peripheral region on the back surface side of the wafer W is provided on the mounting portion 41 in which the heater H is built in, and a thermal change is applied to the peripheral region of the wafer W. Specifically, a ring member 8 having an annular member having an L-shaped cross section, for example, is provided on the mounting portion 41 constituting the sealed container 4, and the rear surface side peripheral portion of the wafer W is supported on the upper surface of the ring member 8. It is configured as follows. The ring member 8 is made of a material having a different thermal conductivity from the mounting portion 41 selected from, for example, aluminum, stainless steel, ceramic, or the like.
[0064]
In such a configuration, the heat conduction from the mounting portion 41 varies depending on the material of the ring member 8 and the gap 81 formed between the ring member 8 and the back surface of the wafer W. For this reason, in the wafer W, the temperature changes between the central region and a region near the part in contact with the ring member 81 (peripheral region of the wafer W). In the meantime, the volatilization rate of the solvent of the coating solution changes. Specifically, when the temperature of the wafer W increases, the solvent in the region increases in volatilization rate, and when the temperature decreases, the solvent in the region decreases in volatilization rate. When controlled to change in the plane, the volatilization rate of the solvent is different in the plane, and thus the film thickness can be controlled in the wafer W plane.
[0065]
In this example, as described above, the volatilization of the solvent of the coating solution is controlled by the combination of the change in the height position of the current plate 5 and the temperature change in the surface of the wafer W. The film thickness of the coating film can be uniformly controlled up to the vicinity. For this reason, even if the outer edge area to be discarded outside the circuit formation area of the wafer W becomes narrow within 5 mm from the outer edge, the coating film can be formed with a sufficiently uniform film thickness up to the area near the outer edge.
[0066]
In this case, the ring member 8 may be of a type in which the entire upper surface of the ring member 8 is in contact with the back surface side of the peripheral region of the wafer W in addition to the L-shaped cross section. At this time, the temperature of the wafer W is adjusted in-plane by the thermal conductivity in the vicinity of the contact portion between the ring member 8 and the wafer W, but the shape and material of the ring member 8 depend on the type of coating film to be formed and other processing conditions. The position and size of the contact portion with the wafer W are appropriately selected.
[0067]
Further, in this embodiment, the ring member 8 is provided to change the heat conduction between the central region and the peripheral region of the wafer W, thereby adjusting the temperature of the wafer W in the plane so that the film thickness of the coating film can be adjusted. Since control is performed, the above-described rectifying plate 5 may be omitted, or the height position may not be changed even if the rectifying plate 5 is provided.
[0068]
As described above, in this embodiment, the wafer W is delivered to the ring member 8. In this case, when the wafer W is placed on the ring member 8, the center positions of the ring member 8 and the wafer W are easily shifted. . If the center position of the wafer W shifts in this way, the uniformity of the coating film thickness deteriorates. Therefore, the wafer W is delivered onto the ring member 8 with the ring member 8 and the center position of the wafer W aligned. Is important, and a method for aligning the center position of the ring member 8 and the wafer W will be described.
[0069]
In this method, after the wafer W is first transferred onto the ring member 8, for example, as shown in FIG. 19, a positioning provided at a position separated from the center position of the ring member 8 on the outer side of the wafer W by an equal distance. A plurality of, for example, three alignment members 82, which are members, are moved in a synchronized manner from a standby position on the outer side of the wafer W to a positioning position in contact with the outer edge of the wafer W, so that the wafer W is driven up, and thus the position is adjusted. It is a combination.
[0070]
These alignment members 82 are provided with a plate-like body 82a, and a part of the outer edge of the wafer W is pressed by a part of the side edge of the plate-like body 82a. One end of the plate-like body 82a is connected to a substantially vertical rotating shaft 83b, and a pulley 83a is connected to the other end of the rotating shaft 83b, and a belt is provided between the pulleys 83a of each rotating shaft 83b. It is laid over. Accordingly, when any one of the rotation shafts 83b is rotated by a motor (not shown), all the rotation shafts 83b are rotated in a synchronized state.
[0071]
Thus, the plate-like members 82a of the alignment members 82 are rotated from the standby position to the positioning position in a synchronized state. In this way, the three alignment members 82 are moved to the positioning position to move the wafer. When the outer edge of W is brought into contact with the outer edge of W, the wafer W is driven to a position where the center position of the ring member 81 and the center position of the wafer W are aligned and positioned. In FIG. 20, reference numeral 83c denotes a bearing.
[0072]
After the wafer W is placed on the ring member 8 in this way, when the wafer W is aligned by moving the alignment member 82, the center positions of the wafer W and the ring member 8 are always aligned. Thus, the uniformity of the coating film thickness can be improved, and the throughput is improved.
[0073]
In this embodiment, in addition to the case where the wafer W is delivered on the ring member 8, it can be applied to the case where the wafer W is delivered on the placement unit 41, and the case where the wafer W is delivered onto the support pins 41 a of the placement unit 41, In any case, since the wafer W is mounted on the ring member 8 and the mounting portion 41 in a state where the center position is aligned, a highly uniform reduced-pressure drying process can be performed. Furthermore, this embodiment can also be applied to a vacuum drying apparatus having a configuration in which the rectifying plate 5 and the ring member 8 are not provided. The “mounting unit” in the claims corresponds to all members on which the wafer W is mounted, and includes a ring member and the like.
[0074]
FIG. 21 shows still another example of the reduced-pressure drying unit 26 according to the present invention, and this example is characterized by a mounting unit on which the wafer W is mounted. In the mounting portion 41 of this example, for example, a first air passage 84a is formed on the outer side immediately outside the region where the ring member 8 is provided so as to penetrate the mounting portion 41 in the vertical direction. A second air passage 84b communicating from the first air passage 84a to the through hole 47a of the lift pin 44 is formed, and the atmosphere in the first air passage 84a is greater than the position where the second air passage 84b branches. An O-ring 84c is provided at a position close to the side in order to prevent outside air from entering the sealed container 4 through the ventilation paths 84a and 84b.
[0075]
Here, when the air passages 84a and 84b are not formed in the mounting portion 41, when the inside of the sealed container 4 is decompressed, the back side of the wafer W and the upper surface of the ring member 8 are adsorbed, and the interior of the container 4 is decompressed. Even if the atmospheric pressure is returned to the atmospheric pressure, the back surface side of the wafer W is still in a reduced pressure state, and the central region on the back surface side of the wafer W is attracted to the mounting portion 41 side, and the wafer W may be warped. However, in the configuration in which the air passages 84a and 84b are provided in the mounting portion 41 as described above, when the inside of the sealed container 4 is returned from the reduced pressure atmosphere to the normal pressure atmosphere, the back side of the wafer W is likely to leak, and the wafer W Since the back surface side of the wafer W is also likely to be at atmospheric pressure, it is possible to suppress the wafer W from warping by suppressing the adsorption between the center region on the back surface side of the wafer W and the mounting portion 41.
[0076]
This configuration can also be applied to a vacuum drying apparatus having a configuration in which the rectifying plate 5 and the ring member 8 are not provided. Even in the mounting portion 41 having a configuration in which the ring member 8 is not provided, the wafer W is placed on the support pins 41a. Since a space is formed between the central area of the wafer W and the mounting portion 41, the present invention can be applied. In this case, the “support member” in the claims includes the ring member 8 and the support pin 41a.
[0077]
FIG. 22 shows still another example of the reduced-pressure drying unit 26 of the present invention. In this example, the current plate 5 is provided so as to be parallel to the wafer W. Specifically, for example, as shown in the figure, the mounting portion 41 is provided with a digimatic indicator 85 that constitutes a parallelism measuring means for measuring the parallelism of the rectifying plate 5. The rectifying plate 5 is moved up and down via the elevating plate 53 a and the support rod 51, and the rectifying plate 5 is adjusted to be parallel to the wafer W. In this case, since the current plate 5 can be accurately aligned so as to be parallel to the wafer W, a coating film having a more uniform thickness can be formed.
[0078]
Next, still another example of the reduced pressure drying unit 26 of the present invention will be described with reference to FIG. In this example, instead of the plate-like rectifying plate 5, a rectifying member 86 configured in a reverse concave shape so as to surround the surface and outer edge of the wafer W is provided. The rectifying member 86 extends substantially downward from a substantially horizontal surface 86a formed so as to face the surface of the wafer W, and extends from the surface to the outer side of the wafer W. And a substantially vertical surface 86b that covers the edge while forming a very small gap with the outer edge, and in the substantially horizontal surface 86a, a large number of air holes 86c are provided in the circumferential direction in the vicinity of the outer edge of the wafer W. Are formed at equal intervals. Here, the gap between the side surface of the wafer W and the substantially vertical surface 86a is set to, for example, about 0.1 mm, and is configured such that a large pressure loss occurs.
[0079]
In this example, for example, the diameter of the mounting portion 87 for mounting the wafer W is set to be approximately the same as the diameter of the wafer W, and the substantially vertical surface 86b is the mounting portion 87 on the lower side of the wafer W. The side surface of the mounting portion 87 is covered with a very small gap. Here, the gap between the side surface of the wafer W and the side surface of the mounting portion 87 and the substantially vertical surface 86b is set to about 0.1 mm, for example, and a large pressure loss is generated here. In this example, the sealed container 4 </ b> A includes a lid body 42 and a lower container 88, and the above-described placement portion 87 is disposed inside the lower container 88.
[0080]
In such a configuration, when the sealed container 4A is placed in a reduced pressure atmosphere, the exhaust flow in the container 4A is formed so as to bypass the rectifying member 86, and the solvent vapor volatilized from the wafer W hits the rectifying member 86. The direction is changed to the outward side and flows along the inside of the flow regulating member 86. At this time, since only a very small gap is formed between the outer edge of the wafer W and the side surface of the mounting portion 87 and the rectifying member 86, a large pressure loss occurs here. For this reason, the solvent vapor volatilized from the wafer W flows out from the vent hole 86c toward the exhaust pipe 45, thereby forming a stable air current that spreads uniformly in the radial direction. Thus, since the solvent vapor spreads uniformly in the radial direction, the film thickness in the peripheral region of the coating film can be further improved, and the film thickness uniformity can be further enhanced.
[0081]
At this time, as shown in FIG. 24, for example, the second side is formed so as to divide the lid body 42 in the vertical direction so as to face the substantially horizontal surface 86a of the rectifying member 86 on the upper side of the rectifying member 86 inside the sealed container 4A. A second straightening plate 89 that is a straightening member may be provided, and a vent 89a may be formed at a position corresponding to the vicinity of the outer edge of the wafer W of the second straightening plate 89. In the configuration of FIG. 24, the vent hole 86 c of the rectifying member 86 is formed on a substantially vertical surface 86 b near the outer edge of the wafer W.
[0082]
In such a configuration, when the inside of the sealed container 4A is placed in a reduced-pressure atmosphere, the solvent vapor volatilized from the wafer W flows out from the vent hole 86c toward the exhaust pipe 45, and the vent hole formed in the second rectifying plate 89 is used. It flows out toward the exhaust pipe 45 through 89a. In this way, by using the dual structure of the rectifying member 86 and the second rectifying plate 89, a stable air flow that spreads more uniformly in the radial direction of the wafer W can be formed, whereby the solvent vapor spreads more uniformly in the radial direction. Therefore, the film thickness in the peripheral region of the coating film can be further improved, and the film thickness uniformity can be further enhanced.
[0083]
The rectifying member 86 and the second rectifying plate 89 can also be applied when the wafer W is placed on the placing portion 41 having the configuration shown in FIG. 6. In this case, the substantially vertical surface 86b is slightly on the side of the wafer W. If it is configured to extend to a position where it covers through a gap, the film thickness in the peripheral region of the coating film formed on the surface of the wafer W can be improved.
[0084]
Further, the vacuum drying unit 26 may be configured as shown in FIG. In the present embodiment, a transfer chamber 9B having a dedicated auxiliary transfer means 91 for transferring a wafer W to the hermetic container 9A is provided adjacent to the hermetic container 9A for performing the reduced-pressure drying process. And the transfer chamber 9B are opened and closed by a gate valve 90 which is an opening / closing member.
[0085]
The auxiliary transfer means 91 transfers the wafer W to and from the main transfer means 24 described above. For example, as shown in the drawing, the two arms 91a are separately provided to the sealed container 9A. It is configured to be able to advance and retreat and freely move up and down. Further, the transfer chamber 9B includes a transfer table 92 including transfer pins 92a that can be moved up and down by an elevating mechanism 92b for transferring the wafer W between the auxiliary transfer unit 91 and the main transfer unit 24. In the figure, 93a is a mounting portion for the wafer W, and 93b is an exhaust pipe. For example, as shown in FIG. 26, the transfer table 92 is configured such that the arm 91a of the auxiliary transfer means 91 and the arm of the main transfer means 24 can be accessed without interfering with the transfer pins 92a. The wafers W can be delivered between them.
[0086]
In such a configuration, with the gate valve 90 closed, the main transfer means 24 loads the wafer W into the transfer chamber 9B through a wafer transfer port (not shown) of the transfer chamber 9B, and passes the transfer pin 92a. The wafer W is delivered to the auxiliary transfer means 91. Then, after the main transfer means 24 is withdrawn, the transfer port is closed, and then the gate valve 90 is opened to transfer the wafer W into the sealed container 9A by the auxiliary transfer means 91.
[0087]
In the present embodiment, first, the wafer W is transferred to the transfer chamber 9B, and after the transfer chamber 9B is closed, the gate valve 90 is opened to transfer the wafer W into the sealed container 9A. When carrying into the container 9A, it can suppress that air | atmosphere penetrates into the container 9A.
[0088]
Further, in the reduced pressure drying unit 26, for example, as shown in FIG. 27, a part of the side wall of the sealed container 9A may be constituted by a transparent body 94 made of, for example, transparent vinyl chloride. For example, the transparent body 94 is attached to the side wall 95a via an O-ring 95c so as to close the opening 95b by forming an opening 95b in the side wall 95a of the sealed container 9A. If it does in this way, there exists an advantage that the mode of the vacuum drying process implemented in the airtight container 9A can be confirmed visually.
[0089]
The vacuum drying unit 26 is mounted on, for example, the shelf units U2 and U3. In this case, the wafer W is loaded into the vacuum drying unit 26 and the wafer W is unloaded from the vacuum drying unit 26 in a predetermined process. The transfer arm 23, the main transfer means 24, and the transfer arm 27 shown in FIG.
[0090]
In consideration of the convenience of access to the reduced pressure drying unit 26 of each of the conveying means in that case, for example, the reduced pressure drying unit 26 shown in FIG. 28 can be proposed. That is, in the reduced pressure drying unit 26 shown in FIG. 28, openings 101 and 102 are formed on both sides of the transfer chamber 9B. Accordingly, each of the transfer means described above can carry the wafer W into and out of the vacuum drying unit 26 through these openings 101 and 102.
[0091]
The mounting unit 41 has a configuration in which the heater H is built in, but as illustrated in FIG. 29, a mounting unit 112 having a temperature adjusting unit, for example, a Peltier element 111 may be used. .
[0092]
The mounting portion 112 includes a main body 110 having a concave portion 117 formed on the upper surface side, and a plate 113 provided on the upper portion of the main body 110 via a sealing material 114 such as an O-ring so as to hermetically close the concave portion 117. It has. The plate 113 is a part on which a substrate such as a wafer W is directly placed. In the recess 117, there are a Peltier element 111 provided on the lower surface of the plate 113 so that the temperature of the plate 113 is adjusted, and a cooling channel 115 for cooling the lower surface of the Peltier element 111. Is provided. For example, cooling water flows through the cooling flow path 115. The cooling fluid circulates through the flow path 116 between a cooling fluid supply source (not shown) disposed outside and the cooling flow path 115.
[0093]
According to the mounting part 112 having the above configuration, the temperature of the substrate such as the wafer W mounted on the plate 113 can be adjusted in a range of 10 ° C. to 40 ° C., for example. Therefore, when the mounting unit 112 is used, the temperature of the wafer W is initially maintained at a low temperature, for example, around 15 ° C. during the vacuum drying, and the solvent evaporates from the coating solution such as a resist solution on the wafer W. For example, when the current plate 5 is brought close to the wafer W and dried while controlling the liquid flow of the coating liquid, the temperature of the wafer W is maintained at room temperature, for example, 23 ° C., and the drying process is performed. Can be properly executed.
[0094]
In the above, the substrate used in the present invention may be an LCD substrate or a photomask reticle substrate. The coating solution is not limited to a resist solution, and an interlayer insulating material, a low dielectric material, a ferroelectric material, a wiring material, an organic metal material, a metal paste, or the like may be used. Furthermore, the coating liquid of the present invention may be applied by a so-called spin coating method, or may be applied by supplying the coating liquid in a spiral shape to the substrate surface.
[0095]
【The invention's effect】
As described above, according to the present invention, the reduced-pressure drying treatment can be performed while ensuring high uniformity of the thickness of the coating film in the reduced-pressure drying apparatus for the substrate used in forming the coating film.
[Brief description of the drawings]
FIG. 1 is a plan view showing the overall structure of an embodiment of a coating film forming apparatus incorporating a reduced-pressure drying unit according to the present invention.
FIG. 2 is a perspective view showing an overall structure in the embodiment.
FIG. 3 is a schematic cross-sectional view showing a configuration of a shelf unit used in the embodiment.
FIG. 4 is a longitudinal sectional view for explaining a coating unit used in the embodiment.
FIG. 5 is a plan view for explaining the coating unit.
FIG. 6 is a longitudinal sectional view showing a reduced pressure drying unit incorporated in the shelf unit.
FIG. 7 is a characteristic diagram showing a pressure curve in a vacuum drying unit.
FIG. 8 is a side view for explaining another embodiment of the vacuum drying unit according to the present invention.
FIG. 9 is a cross-sectional view for explaining still another embodiment of the vacuum drying unit according to the present invention.
FIG. 10 is a characteristic diagram showing a pressure curve in a vacuum drying unit.
FIG. 11 is a cross-sectional view for explaining still another embodiment of the reduced-pressure drying unit according to the present invention.
FIG. 12 is a cross-sectional view for explaining still another embodiment of the reduced-pressure drying unit according to the present invention.
FIG. 13 is a plan view for explaining still another embodiment of the vacuum drying unit according to the present invention.
FIG. 14 is a cross-sectional view for explaining still another embodiment of the reduced pressure drying unit according to the present invention.
FIG. 15 is a sectional view for explaining still another embodiment of the reduced pressure drying unit according to the present invention.
FIG. 16 is a cross-sectional view for explaining still another embodiment of the vacuum drying unit according to the present invention.
FIG. 17 is a side view for explaining still another embodiment of the reduced pressure drying unit according to the present invention.
FIG. 18 is a perspective view showing a part of the still another embodiment.
FIG. 19 is a plan view for explaining a technique for aligning a wafer and a mounting table;
FIG. 20 is a cross-sectional view for explaining the above-described method.
FIG. 21 is a cross-sectional view for explaining still another embodiment of the reduced-pressure drying unit according to the present invention.
FIG. 22 is a cross-sectional view for explaining still another embodiment of the reduced-pressure drying unit according to the present invention.
FIG. 23 is a cross-sectional view for explaining still another embodiment of the reduced-pressure drying unit according to the present invention.
FIG. 24 is a cross-sectional view for explaining still another embodiment of the reduced pressure drying unit according to the present invention.
FIG. 25 is a cross-sectional view for explaining still another embodiment of the reduced pressure drying unit according to the present invention.
FIG. 26 is a plan view for explaining the still another embodiment.
FIG. 27 is a cross-sectional view for explaining still another embodiment of the reduced-pressure drying unit according to the present invention.
FIG. 28 is a cross-sectional view showing another example of a vacuum drying unit.
FIG. 29 is a cross-sectional view showing an example of the internal configuration of another placement unit.
FIG. 30 is a perspective view for explaining a resist solution coating method;
FIG. 31 is a cross-sectional view for explaining a conventional vacuum drying unit.
FIG. 32 is a cross-sectional view showing the state of a coating film when a vacuum drying process is performed in a conventional vacuum drying unit.
[Explanation of symbols]
24 Main transport means
25A coating unit
26 Vacuum drying unit
4,4A, 9A Airtight container
41 Placement section
42 Lid
45 Exhaust pipe
46 Vacuum pump
5 Current plate
53, 65, 7 Rectifier lifting mechanism
55 Pressure sensor
58 Pressure adjuster
59 Heating means
60 holding part
66 Lifting bar
8 Ring member
82 Alignment member
84a, 84b Ventilation path
85 Digimatic indicator
86 Rectification member
89 Second current plate
9B transfer room
90 Gate valve
91 Auxiliary transport means
94 Transparent body

Claims (15)

A hermetically sealed container provided with a placement portion for placing a substrate coated with a coating solution obtained by mixing a component of a coating film and a solvent;
A vacuum evacuation means connected to the sealed container via an exhaust path, and setting the inside of the sealed container in a reduced pressure atmosphere to volatilize the solvent from the coating solution on the substrate;
A rectifying member provided to face the surface of the substrate placed on the placement portion;
A rectifying member lifting mechanism for lifting and lowering the rectifying member;
A pressure detector for detecting the pressure in the sealed container;
The inside of the closed container is evacuated to discharge air, thereby lowering the pressure with a steep slope, and then gradually lowering the pressure by maintaining the pressure slightly higher than the pressure at which the solvent reaches the boiling point until the evaporation of the solvent is completed. When the pressure detection value of the pressure detection unit becomes smaller than a preset set pressure while the pressure is gradually lowered, the rectifying member is And a controller that changes the first position to a second position higher than the first position . A hermetically sealed container provided with a placement portion for placing a substrate coated with a coating solution obtained by mixing a component of a coating film and a solvent;
A vacuum evacuation means connected to the sealed container via an exhaust path, and setting the inside of the sealed container in a reduced pressure atmosphere to volatilize the solvent from the coating solution on the substrate;
A rectifying member provided to face the surface of the substrate placed on the placement portion;
A rectifying member lifting mechanism for lifting and lowering the rectifying member;
A film thickness measuring means for measuring the thickness of the coating film formed on the substrate surface ,
While the inside of the sealed container is in a reduced pressure atmosphere and the solvent is volatilized from the coating solution on the substrate, the rectifying member is moved up and down by the rectifying member lifting mechanism based on the measured value from the film thickness measuring means , A reduced-pressure drying apparatus characterized by changing a height position. The airtight container is provided with a temperature adjusting means for adjusting the temperature of the substrate placed on the placing portion, and the inside of the airtight container is depressurized to evaporate the solvent and / or moisture contained in the coating liquid on the substrate surface. The reduced-pressure drying apparatus according to claim 1 , wherein the temperature of the substrate is adjusted during the operation. The reduced-pressure drying apparatus according to claim 3, wherein while the temperature of the substrate is adjusted by the temperature adjusting means, the pressure reduction in the sealed container by the vacuum evacuating means is stopped. The vacuum drying apparatus according to claim 3 or 4 , wherein the temperature adjusting means is provided in the rectifying member. The vacuum drying apparatus according to any one of claims 3 to 5, wherein the temperature adjusting means can adjust the temperature of the substrate in a range of at least 10 ° C to 23 ° C. The vacuum drying apparatus according to any one of claims 3 to 6 , wherein the temperature adjusting means includes a Peltier element. Detecting the thickness of the pressure and / or the coating film of the sealed container, any one of the temperature control of the substrate by the temperature adjustment means on the basis of the detected value is not claim 3 characterized in that it is carried out 7 The reduced-pressure drying apparatus described in 1. A suspension support connected to the surface side of the rectifying member, and attached to the lid of the sealed container so that the rectifying member can be suspended in a vertically movable state;
Wherein provided on the back side of the rectifying member, according to this rectifying member on one of the rectifying member lift mechanism for changing the height position of the pressing to rectifying member, claims 1, characterized in that it comprises 8 Vacuum drying equipment. The reduced pressure drying apparatus according to claim 9, wherein the rectifying member and the suspension support portion are connected by a spherical joint.   The rectifying member elevating mechanism includes an elevating rod having a back surface side and one end side of the rectifying member in contact with each other, the other end side connected to an exhaust means, and having a vent hole inside. The decompression drying apparatus according to claim 9 or 10, wherein the straightening member is pressed by the lifting rod while the inside of the lifting rod is sucked by the exhaust means.   The sealed container includes a lid body and a lower container, and is formed by bringing these peripheral portions into close contact with each other. A sealing member having two sizes is provided at a contact portion between the lid body and the lower container, The reduced-pressure drying apparatus according to any one of claims 1 to 11, wherein a region between the members is evacuated by an evacuation unit to adsorb a contact portion between the lid and the lower container.   The reduced-pressure drying apparatus according to any one of claims 1 to 12, wherein an annular member that is in contact with a peripheral region on the back surface side of the substrate and has a thermal conductivity different from that of the mounting portion is provided in the mounting portion.   The reduced-pressure drying apparatus according to any one of claims 1 to 13, further comprising a second rectifying member provided in a position closer to the exhaust path than the rectifying member inside the sealed container. Applying a coating solution obtained by mixing the components of the coating film and the solvent onto the substrate surface;
Placing the substrate coated with the coating solution in a sealed container;
The inside of the closed container is evacuated to discharge air, thereby lowering the pressure with a steep slope, and then gradually lowering the pressure by maintaining the pressure slightly higher than the pressure at which the solvent reaches the boiling point until the evaporation of the solvent is completed. Process,
The rectifying member is disposed so as to face the substrate at a first position on the upper side of the substrate placed in the sealed container until the pressure is set in the pressure region in the step of gradually lowering the pressure. Providing a step;
A second step of changing the rectifying member to a second position higher than the first position so as to face the substrate when the pressure becomes lower than the set pressure. A coating film forming method.

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