JP2011096711A - Reduced pressure drying apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the fluctuation in atmospheric temperature inside a chamber over the entire processing step period, from starting of reduced-pressure drying process to the completion of purging. <P>SOLUTION: In a reduced-pressure drying unit 12, a roller transport path 38B for flat flowing of a processed substrate G is pulled into a chamber 40, and a substrate lift mechanism 60 raises/lowers the substrate G by using a lift pin 62 inside the chamber 40. In order to reduce the fluctuations in the atmospheric temperature inside the chamber 40, a shielding plate 100 is arranged so as to cover the lower part of the substrate G near the roller transport path. The shielding plate 100 includes a round opening 100a, which allows the lift pin 62 to penetrate for raising/lowering, and a square opening 100b for avoiding the internal roller transport path 38B from interfering with a roller 42B. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a reduced pressure drying apparatus that performs a drying process in a reduced pressure state on a coating liquid film (coated film) formed on a substrate to be processed.

  For example, in a photolithography process for manufacturing a flat panel display (FPD), a vacuum drying apparatus is used to appropriately dry a coating film of a resist solution coated on a substrate to be processed such as a glass substrate prior to pre-baking. Yes.

  A conventional typical vacuum drying apparatus is, for example, as described in Patent Document 1, a tray or shallow container-type lower chamber having an open upper surface, and an upper surface of the lower chamber that is hermetically adhered or fitted. And a lid-like upper chamber configured to be possible. A stage is disposed in the lower chamber, and a substrate is placed horizontally on the stage, and then the chamber is closed (the upper chamber is in close contact with the lower chamber) to perform a vacuum drying process. I have to.

  However, such a stage-type vacuum drying apparatus has the disadvantage that it requires a transfer robot and a large upper chamber opening / closing mechanism to carry in and out the substrate as the substrate becomes larger. .

  In a vacuum drying apparatus, during vacuum drying (vacuum evacuation), the atmospheric temperature in the chamber suddenly drops from the initial temperature (normally normal temperature), and the vacuum drying (vacuum evacuation) is stopped and the chamber is filled with nitrogen gas or the like. When purging, the ambient temperature rises significantly to a temperature well above the initial temperature, and when purging is stopped, the ambient temperature decreases toward room temperature. The temperature of the pin that supports the substrate also changes in accordance with the change in the atmospheric temperature in the chamber, and this causes a problem that the transfer pin (a kind of film thickness variation) of the support pin is attached to the resist film. Yes.

  In view of the above-mentioned problems, the present applicant has carried out the loading and unloading of the substrate efficiently and smoothly by roller transport, and the support pin has a hollow portion in which the tip end portion is closed and the side wall is provided with a vent hole. Comprised of a cylindrical body, by flowing a temperature adjusting gas inside the support pins, the thermal influence of the support pins from the ambient or ambient temperature is compensated for temperature, and the thermal influence of the board from the support pins is reduced. A reduced-pressure drying apparatus as described above was developed and disclosed in Patent Document 2.

JP2000-181079 JP2009-38231A

  In addition to the reduced-pressure drying apparatus disclosed in Patent Document 2, the applicant of the present application uses a normal inexpensive support pin that does not have a temperature control mechanism, and the thermal effect that the coating film on the substrate receives through the support pin (particularly, As a result of the development of a vacuum drying apparatus capable of suppressing pin transfer marks as much as possible, the present invention was born as one of the results.

  That is, the present invention efficiently and safely carries in and out the substrate by roller conveyance, and reduces the variation in the atmospheric temperature in the chamber throughout the entire process time from the start of the vacuum drying process to the end of purging, Provided is a vacuum drying apparatus that reduces the thermal influence that a substrate receives through support pins and improves the quality of a coating film.

  A reduced-pressure drying apparatus according to a first aspect of the present invention is a reduced-pressure drying apparatus that performs a reduced-pressure drying process on a coating liquid film formed on a substrate to be processed, and has a space for accommodating the substrate in a horizontal state. A decompressable chamber, an exhaust mechanism for evacuating the inside of the chamber in a sealed state for the decompression drying process, and a roller transport path continuous in the outside of the chamber. A transport mechanism for transporting the substrate into or out of the chamber by transport, and a number of support pins arranged discretely in the chamber to support the substrate horizontally at the tip of the pin to raise and lower it When the drying process is performed, the tip of the support pin is made higher than the roller conveyance path to support the substrate, and when the substrate is loaded / unloaded, the tip of the support pin is moved to the roller Carrying A substrate lift mechanism that allows the substrate to be transported by the transport mechanism lower than the path, a buzzing mechanism that supplies a purging gas into the chamber to finish the reduced-pressure drying process, In order to reduce fluctuations in the atmospheric temperature, the light source has a shielding plate provided at a position covering the bottom of the substrate near the roller conveyance path.

  In the above apparatus configuration, the transport mechanism carries the substrate in and out by roller transport, and the substrate lift mechanism moves the substrate in the chamber between the transport surface of the roller transport path and a height position for vacuum drying treatment higher than that. Raise and lower between. During the vacuum drying process, an air flow is generated in the chamber by the vacuum exhaust of the exhaust mechanism, the liquid (solvent) is volatilized from the coating film on the substrate, and the atmospheric temperature in the chamber becomes lower than the initial temperature (for example, normal temperature). Then, when purging gas is supplied into the chamber from the purging mechanism in order to end the reduced-pressure drying process, the purging gas flows in the chamber, and the atmospheric temperature in the chamber rises to a height exceeding the initial temperature. In the present invention, since the shielding plate is disposed so as to cover the bottom of the substrate near the roller conveyance path, the airflow in the chamber is controlled by the shielding plate, and the variation in the atmospheric temperature in the chamber is reduced. This reduces the thermal effect that the substrate receives through the support pins, and improves the quality of the coating film on the substrate.

  A reduced-pressure drying apparatus according to a second aspect of the present invention is a reduced-pressure drying apparatus that performs a reduced-pressure drying process on a coating liquid film formed on a substrate to be processed, and includes a space for storing the substrate in a horizontal state. A depressurizable chamber, and a roller conveyance path that is continuous inside and outside the chamber, and a conveyance mechanism that carries the substrate into the chamber by roller conveyance on the roller conveyance path, or unloads the substrate from the chamber, An exhaust mechanism for evacuating the chamber in a sealed state for the vacuum drying process; a buzzing mechanism for supplying a purging gas into the chamber to end the vacuum drying process; and the vacuum drying process and In order to reduce the atmospheric temperature in the chamber during the purging, a shielding plate provided to cover the bottom of the substrate, and the substrate during the vacuum drying process A plurality of support pins discretely provided on the shielding plate for supporting horizontally at the tip of the screen, and coupled to the shielding plate, and when performing the drying process, the tip of the support pin is positioned more than the roller conveyance path. The substrate can be supported by the support pins, and when the substrate is carried in / out, the tip of the support pin is lowered from the roller conveyance path so that the substrate can be conveyed by the conveyance mechanism. In order to make it possible, a shielding plate lifting mechanism for moving the shielding plate up and down is provided.

  In the above apparatus configuration, the transport mechanism carries the substrate in and out by roller transport, and the shielding plate lifting mechanism moves the substrate through the airflow shielding plate and the support pin for the transport surface of the roller transport path and a vacuum drying process higher than that. Raise and lower the height position. During the vacuum drying process, an air flow is generated in the chamber by the vacuum exhaust of the exhaust mechanism, the liquid (solvent) is volatilized from the coating film on the substrate, and the atmospheric temperature in the chamber becomes lower than the initial temperature (for example, normal temperature). Then, when purging gas is supplied into the chamber from the purging mechanism in order to end the reduced-pressure drying process, the purging gas flows in the chamber, and the atmospheric temperature in the chamber rises to a height exceeding the initial temperature. In the present invention, since the shielding plate is disposed so as to cover the bottom of the substrate near the roller conveyance path, the airflow in the chamber is controlled by the shielding plate, and the variation in the atmospheric temperature in the chamber is reduced. This reduces the thermal effect that the substrate receives through the support pins, and improves the quality of the coating film on the substrate.

  A reduced-pressure drying apparatus according to a third aspect of the present invention is a reduced-pressure drying apparatus that performs a reduced-pressure drying process on a coating solution film formed on a substrate to be processed, and has a space for accommodating the substrate in a horizontal state. A decompressable chamber, an exhaust mechanism for evacuating the inside of the chamber in a sealed state for the decompression drying process, and a roller transport path continuous in the outside of the chamber. A transport mechanism for transporting the substrate into or out of the chamber by transport, and a number of lift pins discretely arranged in the chamber for horizontally supporting the substrate up and down at the tip of the pin When the drying process is performed, the tip of the lift pin is made higher than the roller conveyance path to support the substrate, and when the substrate is carried in / out, the tip of the lift pin is A substrate lift mechanism that enables the substrate to be transported by the transport mechanism at a lower position than the transport path, and a buzzing mechanism that supplies a purging gas into the chamber to finish the reduced-pressure drying process. The purging mechanism has a gas ejection portion that ejects the purging gas at a position higher than the roller conveyance path.

  In the above apparatus configuration, the transport mechanism carries the substrate in and out by roller transport, and the substrate lift mechanism moves the substrate in the chamber between the transport surface of the roller transport path and a height position for vacuum drying treatment higher than that. Raise and lower between. During the vacuum drying process, an air flow is generated in the chamber by the vacuum exhaust of the exhaust mechanism, the liquid (solvent) is volatilized from the coating film on the substrate, and the atmospheric temperature in the chamber becomes lower than the initial temperature (for example, normal temperature). Then, when purging gas is supplied into the chamber from the purging mechanism in order to end the reduced-pressure drying process, the purging gas flows in the chamber, and the atmospheric temperature in the chamber rises to a height exceeding the initial temperature. In the present invention, the gas ejection portion of the purging mechanism ejects the purging gas at a position higher than the roller conveyance path, thereby reducing the variation in the atmospheric temperature in the chamber. This reduces the thermal effect that the substrate receives through the support pins, and improves the quality of the coating film on the substrate.

  According to the reduced-pressure drying apparatus of the present invention, with the above-described configuration and operation, it is possible to efficiently and safely carry in and out the substrate by roller conveyance, and the entire processing process time from the start of the reduced-pressure drying process to the end of purging. Thus, the variation in the ambient temperature in the chamber can be reduced, the thermal influence on the support pins or the substrate can be reduced, and the processing quality can be improved.

It is a top view which shows the structure of the resist coating apparatus incorporating the reduced pressure drying unit (reduced pressure drying apparatus) in one Embodiment of this invention. It is a top view which shows the structure in the said reduced pressure drying unit. It is a front longitudinal cross-sectional view which shows the state of each part at the time of board | substrate carrying in / out in the said reduced pressure drying unit. It is a front longitudinal cross-sectional view which shows the state of each part at the time of board | substrate carrying in / out in the said reduced pressure drying unit. It is a partial expansion perspective view which shows the structure of the shielding board in embodiment. It is a partial side surface longitudinal cross-sectional view which shows the state of each part in the said decompression drying unit during the decompression drying process. It is a partial side surface longitudinal cross-sectional view which shows the state of each part in purging in the said reduced pressure drying unit. It is a schematic plan view showing the position of a representative measurement point selected for measuring the atmospheric temperature in the chamber in the embodiment and the comparative example. In the structure of embodiment, it is a plot figure which shows the characteristic that the atmospheric temperature in a chamber and a pressure change during a reduced pressure drying process and parsing. In the structure of the 1st modification, it is a plot figure which shows the characteristic that the atmospheric temperature in a chamber and a pressure change during a reduced pressure drying process and parsing. In the structure of the 2nd modification, it is a plot figure which shows the characteristic that the atmospheric temperature in a chamber and a pressure change during a reduced pressure drying process and parsing. In the structure of a comparative example (prior art), it is a figure which shows the characteristic that the atmospheric temperature in a chamber and a pressure change during a reduced pressure drying process and parsing. It is a part which shows the change of the lift pin temperature just before the reduced pressure drying process when a reduced pressure drying process / parsing process is repeated many times. It is a front longitudinal cross-sectional view which shows the state of each part at the time of board | substrate carrying in / out in the reduced pressure drying unit of 2nd Embodiment. It is a partial side surface longitudinal cross-sectional view which shows the state of each part in the said decompression drying unit during the decompression drying process.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows a configuration example of a resist coating apparatus for manufacturing an FPD to which the reduced pressure drying apparatus of the present invention can be applied.

  In this resist coating apparatus, a flat-flow resist coating unit 10 and a vacuum drying unit 12 are arranged side by side in the same substrate transport direction (X direction). First, the configuration and operation of the resist coating unit 10 will be described.

  The resist coating unit 10 floats a substrate to be processed such as a glass substrate G by air pressure and supports it horizontally, and a substrate G floating horizontally on the floating stage 14 in the longitudinal direction of the stage ( A substrate transport mechanism 16 for transporting in the X direction), a resist nozzle 18 for supplying a resist solution to the upper surface of the substrate G transported on the floating stage 14, and a nozzle refresh unit 20 for refreshing the resist nozzle 18 between coating processes. And have.

  A number of gas injection ports 22 for injecting a predetermined gas (for example, air) upward are provided on the upper surface of the levitation stage 14, and the substrate G is placed on the upper surface of the stage by the pressure of the gas injected from the gas injection ports 22. It is configured to rise to a certain height.

  The substrate transport mechanism 16 includes a pair of guide rails 24A and 24B extending in the X direction across the levitation stage 14, a slider 26 that can reciprocate along the guide rails 24A and 24B, and the substrate G on the levitation stage 14. And a substrate holding member (not shown) such as a suction pad provided on the slider 26 so as to detachably hold both side ends of the slider 26, and the slider 26 is moved in the transport direction by a linear movement mechanism (not shown). By moving in the (X direction), the substrate G is floated and conveyed on the floating stage 14.

  The resist nozzle 18 is a long nozzle that extends across the floating stage 14 in a horizontal direction (Y direction) perpendicular to the transport direction (X direction), and passes through the substrate G at a predetermined coating position. The resist liquid is discharged in a strip shape from the slit-shaped discharge port to the upper surface of the substrate. The resist nozzle 18 is configured to be movable in the X direction integrally with a nozzle support member 28 that supports the nozzle, and can be moved up and down in the vertical direction (Z direction). Can be moved between.

  The nozzle refresh unit 20 is held by the column member 30 at a predetermined position above the levitation stage 14, and as a preparation for coating processing, a priming processing unit 32 for causing the resist nozzle 18 to discharge a resist solution, A nozzle bath 34 for keeping the resist discharge port of the nozzle 18 in an atmosphere of solvent vapor for the purpose of preventing drying, and a nozzle cleaning mechanism 36 for removing the resist adhering to the vicinity of the resist discharge port of the resist nozzle 18 are provided. Yes.

  Next, main operations in the resist coating unit 10 will be described. First, the substrate G sent from, for example, roller conveyance from a previous processing unit (not shown) is loaded into a loading portion set on the front end side on the stage 14, and the slider 26 waiting there moves the substrate G. Hold and receive. On the levitation stage 14, the substrate G receives the pressure of the gas (air) ejected from the gas ejection port 22 and keeps the levitation state in a substantially horizontal posture.

  The slider 26 moves in the transport direction (X direction) toward the reduced pressure drying unit 12 while holding the substrate, and when the substrate G passes under the resist nozzle 18, the resist nozzle 18 moves to the upper surface of the substrate G. By discharging the resist solution in a strip shape toward the substrate, a liquid film of the resist solution is formed on one surface so that a carpet is laid on the substrate G from the front end to the rear end of the substrate. The substrate G thus coated with the resist solution is then floated and conveyed on the floating stage 14 by the slider 26, passes over the rear end of the floating stage 14 and transfers to a roller conveyance path 38 to be described later, where the holding by the slider 26 is released. Is done. The substrate G that has transferred to the roller transport path 38 is then transported on the roller transport path 38 by roller transport, as will be described later, and is carried into the subsequent vacuum drying unit 12.

  After the coated substrate G is sent out to the reduced-pressure drying unit 12 side as described above, the slider 26 returns to the carry-in portion on the front end side of the floating stage 14 in order to receive the next substrate G. The resist nozzle 18 moves from the application position (resist liquid discharge position) to the nozzle refresh unit 20 after completing one or a plurality of application processes, and refreshes or prepares for nozzle cleaning, priming processes, and the like. Then return to the application position.

  A roller conveyance path 38 is laid on the extension of the floating stage 14 of the resist coating unit 10 (downstream in the conveyance direction). The roller conveyance path 38 is continuously laid inside and outside (front and rear) of the chamber 40 of the vacuum drying unit 12.

  Below, the structure and effect | action of the reduced pressure drying unit 12 in this embodiment are demonstrated.

  As shown in FIG. 1, the roller conveyance path 38 around the vacuum drying unit 12 includes a conveyance-side roller conveyance path 38 </ b> A laid on the conveyance upstream side of the chamber 40, i.e., the carry-in side, and an interior laid in the chamber 40. The roller conveyance path 38 </ b> B and a carry-out side roller conveyance path 38 </ b> C laid on the conveyance downstream side of the chamber 40, that is, on the carry-out side.

  The roller conveyance paths 38A, 38B, and 38C of each part are rotated by rotating a plurality of rollers 42A, 42B, and 42C arranged at appropriate intervals in the conveyance direction (X direction) by respective independent or common conveyance driving units. G is sent in the conveyance direction (X direction) by roller conveyance. Here, the carry-in side roller conveyance path 38A functions to receive the substrate G unloaded from the floating stage 14 of the resist coating unit 10 as an extension of the floating conveyance, and send it into the chamber 40 of the vacuum drying unit 12 by roller conveyance. . The internal roller transport path 38B draws the substrate G sent by roller transport from the carry-in side roller transport path 38A into the chamber 40 by roller transport at the same speed, and the substrate G that has been subjected to the vacuum drying process in the chamber 40. It functions so as to be sent out to the outside of the chamber 40 (back stage) by roller conveyance. The carry-out side roller conveyance path 38C functions to pull out the processed substrate G sent out from the internal roller conveyance path 38B in the chamber 40 by roller conveyance at the same speed and send it to a subsequent processing section (not shown). To do.

  As shown in FIGS. 1 to 4, the chamber 40 of the vacuum drying unit 12 is formed in a relatively flat rectangular parallelepiped, and has a space in which the substrate G can be accommodated horizontally. A pair of (upstream and downstream) chamber sidewalls facing each other in the transport direction (X direction) of the chamber 40 is formed with a slit-shaped carry-in port 44 and a carry-out port that are formed in such a size that the substrate G can finally pass through in a flat flow. 46 are provided. Further, gate mechanisms 48 and 50 for opening and closing the carry-in port 44 and the carry-out port 46 are attached to the outer wall of the chamber 40. The upper wall portion or the upper lid 52 of the chamber 40 is removable for maintenance.

  As shown in FIGS. 2 to 4, the roller conveyance path of this embodiment has an inner roller conveyance path 38 </ b> B and the outside (the carry-in side / the carry-out side) on the lower surface (or the vicinity thereof) of the carry-in port 44 and the carry-out port 46. Roller type rollers 47 and 49 are provided for tightly connecting the roller conveyance paths 38A and 38C, respectively.

  Although not shown in the drawings, each gate mechanism 48 and 50 has a lid or a valve body capable of airtightly closing the slit-shaped loading / unloading port (44, 46), and the lid body is horizontally opposed to the loading / unloading port (44, 46). A first cylinder (not shown) that moves up and down between a vertical forward movement position and a lower vertical backward movement position, and a horizontal movement that tightly and tightly attaches the lid to the loading / unloading port (44, 46). A second cylinder (not shown) is provided for horizontal movement between the moving position and a horizontal return position separated and separated.

  In the chamber 40, the rollers 42B constituting the inner roller conveyance path 38B are arranged in a row at an appropriate distance in the conveyance direction (X direction) at a height position corresponding to the carry-in / out port (44, 46). A part or all of the rollers 42B are connected to a rotational drive source 54 such as a motor provided outside the chamber 40 via a suitable transmission mechanism 56. Each roller 42B has a plurality of large-diameter rings or rollers 45 fixed to a relatively thin shaft 43 at predetermined intervals, and both ends of the shaft 43 are provided on the left and right side walls of the chamber 40 or in the vicinity thereof. The bearing 58 is rotatably supported.

  The roller 42A of the carry-in side roller conveyance path 38A has the same configuration as the roller 42B of the inner roller conveyance path 38B, and although not shown, both ends thereof are rotatably supported by bearings fixed to a frame or the like. The rotary drive source 54 for the inner roller conveyance path 38B is rotated by a common or separate rotary drive source. The same applies to the roller 42C of the carry-out side roller conveyance path 38C.

  As shown in FIGS. 3 and 4, the vacuum drying unit 12 includes a substrate lift mechanism 60 for supporting the substrate G horizontally in the chamber 40 and raising and lowering it. The substrate lift mechanism 60 includes a large number (preferably 20 or more) of lift pins (support pins) 62 that are discretely arranged in a predetermined arrangement pattern (for example, in a matrix) in the chamber 40, and these lift pins 62. A plurality of horizontal rods or horizontal plate pin bases 64 that support the predetermined base or group at a position lower than the inner roller transport path 38B, and the outside (lower) of the chamber 40 for moving each pin base 64 up and down. 1) or a plurality of lifting drive sources such as a cylinder 66.

  More specifically, a plurality of (preferably three or more) lift pins 62 are vertically arranged in a row in a gap between two rollers 42B and 42B adjacent to each other in parallel to the roller 42B (in the Y direction) at regular intervals. A plurality of (preferably six or more) lift pin rows are provided at appropriate intervals in the transport direction (X direction), and one or a plurality of pairs (two in the illustrated example) are provided on each pin base 64. Support the lift pin row. Then, the upper end of the elevating support shaft 70 penetrating the bottom wall of the chamber 40 through the seal member 68 is coupled to the lower surface of each pin base 64, and the lower end of each pin base 64 is connected to the outside (lower) of the chamber 40. The lift drive source 66 is connected via a common horizontal support plate 72.

  In the substrate lift mechanism 60 having such a configuration, the lift drive source 66 is driven forward (up) or backward (down) by a fixed stroke, so that all the lift pins 62 are pinned via the lift support shaft 70 and the pin base 64. 3 and FIG. 7, the pin tip is lowered (lowered) as shown in FIGS. 3 and 7, and the pin tip is roller-conveyed as shown in FIGS. It can be moved up and down between the forward (upward) positions that are higher than the path 38B.

  As a preferred embodiment, the lift pin 62 is neither a type with a temperature control mechanism that allows air-cooled gas to pass therethrough or a special ultra-fine type, but a pin tip of a rigid hollow tube made of, for example, stainless steel (SUS). It has a normal and inexpensive pin structure with a diameter of about 2 mm, for example. As described above, since the lift pins 62 are relatively thick and rigid, the number of lift pins 62 necessary for the substrate lift mechanism 60 to raise and lower the substrate G stably and smoothly is much smaller than that of the special ultrafine type. I'll do it. However, it is also possible to use the above-mentioned type with a temperature control mechanism or the above-mentioned special ultra-fine type support pin for the lift pin 62.

  Exhaust ports 74 are formed at one or a plurality of locations on the bottom wall of the chamber 40. A vacuum exhaust device 78 is connected to these exhaust ports 74 via an exhaust pipe 76. Each vacuum evacuation device 78 has a vacuum pump for evacuating the chamber 40 from the atmospheric pressure state to maintain a reduced pressure state of a predetermined degree of vacuum. In addition, in order to average the dispersion | variation in the exhaust capability of these several vacuum exhaust apparatuses 78, you may connect each exhaust pipe 76 with a connection pipe (not shown).

  A pair of purging gas ejection portions 80 extending in the transport direction (X direction) along the chamber side wall are provided on the left and right sides of the inner roller transport path 38B in the chamber 40. These purging gas ejection portions 80 are formed of, for example, a hollow tube (or a porous hollow tube formed by sintering metal powder) having a slit-shaped or porous gas ejection port, and a pipe 82 (FIG. 2). Through a purging gas supply source (not shown). When returning from the depressurized state to the atmospheric pressure state with the chamber 40 sealed at the end of the vacuum drying process, the purging mechanism is activated to perform purging from the slit-shaped (or perforated) gas outlet of the purging gas ejection portion 80. The gas (for example, nitrogen gas, clean air, etc.) is ejected.

  As one of the features in this embodiment, the purging gas ejection part 80 is provided at a position higher than the inner roller conveyance path 38B (FIG. 1), and the purging gas is horizontally (or above) at a position higher than the roller conveyance surface. It comes to spout. Preferably, the gas ejection port of the purging gas ejection part 80 is provided at a position higher by 10 mm or more (more preferably 20 mm to 30 mm) than the conveyance surface of the roller conveyance path.

  The vacuum drying unit 12 includes a substrate lift mechanism 60 that draws the roller transport path 38 that performs the flat flow of the substrate G into the chamber 40 as described above, and lifts and lowers the substrate G with the lift pins 62 in the chamber 40. In order to reduce the fluctuation of the ambient temperature in the chamber 40, a shielding plate 100 is provided so as to cover the bottom of the substrate G near the roller conveyance path.

  The shielding plate 100 is made of, for example, a resin or an aluminum plate, has an area slightly larger than that of the substrate G (FIGS. 1 and 2), and has a circular opening 100a for allowing the lift pins 62 to pass up and down. And a rectangular opening 100b for avoiding interference with the roller 42B of the inner roller conveyance path 38B (FIGS. 5, 6, and 7).

  As a preferred embodiment, the shielding plate 100 is fixed at a certain height, that is, higher than the shaft 43 of the roller 42B, for example, by a number of support rods 102 extending vertically upward from the bottom surface of the chamber 40 (the top surface of the roller 45). It is supported horizontally at a position lower than the roller conveyance surface.

  Next, the operation of the reduced pressure drying unit 12 in this embodiment will be described.

  As described above, the substrate G on which the resist solution is applied by the resist coating unit 10 adjacent to the upstream side is transferred to the carry-side roller conveyance path 38A from the floating conveyance path on the floating stage 14 in a flat flow. After that, as shown in FIG. 3, the substrate G moves by roller conveyance on the carry-in side roller conveyance path 38 </ b> A, and eventually enters the chamber 40 of the vacuum drying unit 12 from its carry-in port 44. At this time, the gate mechanism 48 keeps the carry-in entrance 44 open.

  The inner roller conveyance path 38B also performs a roller conveyance operation at the same conveyance speed as the roller conveyance operation of the carry-in side roller conveyance path 38A by the rotational drive of the rotation drive source 54, and as shown in FIG. The substrate G entered from 44 is drawn into the interior of the chamber 40 by roller conveyance. At this time, the substrate lift mechanism 60 waits for all the lift pins 62 in a backward movement (downward) position where the tip ends of the pins are lower than the conveyance surface of the internal roller conveyance path 38B. When the substrate G arrives at a predetermined position substantially in the center of the chamber 40, the roller transfer operation of the internal roller transfer path 38B stops. At the same time or just before this, the roller conveyance operation of the carry-in side roller conveyance path 38A may be stopped.

  As shown in FIG. 3, when the substrate G to be subjected to the vacuum drying process is carried into the chamber 40 from the resist coating unit 10 on the upstream side or the upstream side as described above, as shown in FIG. The preceding substrate G that has just undergone the vacuum drying treatment in the chamber 40 is moved out of the chamber 40 from the carry-out port 46 by continuous roller conveyance at a constant speed on the inner roller conveyance 38B and the unloading-side roller conveyance path 38C. It is sent to the processing section next to the downstream side in a flat stream.

  As described above, the substrate G on which the resist solution has been applied by the resist coating unit 10 is transferred to the chamber 40 of the vacuum drying unit 12 by continuous roller conveyance on the carry-in side roller conveyance path 38A and the internal roller conveyance path 38B. It is brought in. Immediately after this, the gate mechanisms 48 and 50 are operated to close the carry-in port 44 and the carry-out port 46 that have been opened so far, thereby sealing the chamber 40.

  Next, the substrate lift mechanism 60 moves the elevating cylinder 66 forward so that all the pin bases 64 are moved to a predetermined height position in the chamber 40 where the tip ends of all the lift pins 62 exceed the transfer surface of the internal roller transfer path 38B. Raise it by a predetermined stroke all at once. As shown in FIG. 6, the substrate G is transferred from the inner roller transport path 38 </ b> B to the pin tip of the lift pin 62 by the forward movement (upward) operation of the substrate lift mechanism 60, and is directly moved to the inner roller transport path 38 </ b> B. Lifted up.

  In this way, a desired clearance H (for example, 4 to 15 mm) is formed between the upper surface of the substrate G placed on the tip of the lift pin 62 that has moved up to the forward movement position and the ceiling 52 of the chamber 40 (FIG. 6).

  On the other hand, immediately after the chamber 40 is sealed, the evacuation device 78 is operated, and the evacuation of the chamber 40 is started. By this evacuation, the pressure in the chamber 40 is changed from the atmospheric pressure (101325 Pa) up to that time to a vacuum pressure, and the solvent (thinner) evaporates from the resist liquid film on the substrate G in an atmosphere of this reduced pressure state. Due to the heat of vaporization, the atmospheric temperature in the chamber 40 is rapidly lowered from the normal temperature (about 25 ° C.).

  The fluctuation range of the atmospheric temperature in the chamber during the vacuum evacuation (especially immediately after the start of the vacuum drying) varies depending on the location and has a considerable variation. As will be described later, the atmospheric temperature in the chamber during evacuation has conventionally been lowered to about −15 ° C. (FIG. 12), but in this embodiment, it is lowered to only about 0 ° C. at the lowest. (FIG. 9).

  During evacuation, gas (mostly air) remaining in the chamber 40 flows toward the exhaust port 74 at the bottom of the chamber 40, and airflow is generated in each part of the chamber 40 (FIG. 6). In this embodiment, since the shielding plate 100 is provided at a position higher than the shaft 43 of the roller 42B, the turbulence is blocked by the shielding plate 100 even if the airflow rises around the shaft 43, the pin base 64, and the like. , It does not hit the lower surface of the substrate G.

  After a certain time has elapsed since the start of vacuum drying (evacuation), or when the vacuum pressure in the chamber 40 reaches a set value (for example, about 30 Pa), the output signal of a timer or pressure sensor (not shown) is output. Respond to finish the vacuum drying process. For this purpose, the substrate lift mechanism 60 moves the lifting cylinder 66 backward so that all the pin bases 64 are moved to a predetermined height position where the tip ends of all the lift pins 62 are lower than the transport surface of the internal roller transport path 38B. Move down a predetermined stroke all at once. By the backward movement (downward movement) of the substrate lift mechanism 60, the substrate G is transferred from the tip of the lift pin 62 to the internal roller transport path 38B in a horizontal posture. Then, the purging mechanism is activated, and the purging gas is supplied into the chamber 40 from the purging gas ejection part 80 at a predetermined flow rate. In this embodiment, the purging gas ejection unit 80 ejects the purging gas substantially horizontally at a position 20 to 30 mm higher than the conveyance surface of the roller conveyance path 38B. The evacuation operation of the vacuum evacuation device 78 may be stopped simultaneously with the start of purging, or may be stopped after a predetermined time has elapsed.

As shown in FIG. 7, the purging gas ejected substantially horizontally from the purging gas ejection portion 80 is the uppermost space SP ₁ between the ceiling 52 of the chamber 40 and the substrate G, and between the substrate G and the shielding plate 100. The intermediate space SP ₂ and the lowermost space SP ₃ between the shielding plate 100 and the bottom surface of the chamber 40.

Purging gas sent into the top space SP ₁ is missing from the prevailing rapidly in this space SP ₁ before and after the gap of the substrate G downward, it flows toward the outlet 74 of the chamber 40 the bottom.

The purging gas sent into the intermediate space SP ₂ passes through the openings 100a and 100b of the shielding plates 100 in various places while diffusing into the space SP ₂ or passes downward through the gaps before and after the substrate G to the lowermost part. and it flows down to the space SP _3.

Purging gas fed into the bottom space SP _3, and the opening 100a of the shield plate 100 from the intermediate space SP _2, a purging gas which has descended through the 100b bottom space SP ₃ is the roller in the bottom space SP ₃ It flows toward the exhaust port 74 at the bottom of the chamber 40 while colliding with members such as the shaft 43 and the pin base 64 of 42B.

  Due to this purging, the pressure in the chamber 106 increases rapidly from the set value or the lowest value (about 30 Pa) toward the atmospheric pressure, and accordingly, the atmospheric temperature in the chamber well exceeds the temperature (room temperature) before the vacuum drying treatment. Rapid rise to temperature.

  The fluctuation range of the increase of the atmospheric temperature in the chamber due to this purging varies depending on the location and has considerable variations. As will be described later, the atmospheric temperature in the chamber during purging has conventionally exceeded about 50 ° C. (FIG. 12), but in this embodiment, it is the highest and only rises to about 32 ° C. (FIG. 9).

Thus, when the pressure in the chamber 40 rises due to purging and eventually reaches atmospheric pressure, the purging gas ejection unit 80 stops supplying the purging gas at this timing (time point T _e ) in response to the pressure sensor. When the purging gas does not flow in the chamber 40, the atmospheric temperature in the chamber is lowered to be equal to the temperature of the purging gas filling the chamber (usually substantially the same temperature as room temperature).

  Then, after a predetermined time has elapsed since the supply of the purging gas was stopped, the gate mechanisms 48 and 50 are operated to open the carry-in port 44 and the carry-out port 46. Next, a roller transport operation is started on the inner roller transport path 38B and the unload-side roller transport path 38C, and the substrate G that has just undergone the decompression drying process is transported by roller transport from the transport outlet 46 and is directly sent to the subsequent processing section. Sent in a flat stream. Simultaneously with the carry-out operation of the processed substrate G, as shown in FIG. 3, the subsequent substrate G from the resist coating unit 10 is transferred by continuous roller conveyance on the carry-in side roller conveyance path 38A and the internal roller conveyance path 38B. It is carried into the chamber 40 from the carry-in entrance 44.

As described above, the reduced-pressure drying unit 12 of this embodiment is located at a position covering the bottom of the substrate G near the roller conveyance path, preferably higher than the shaft 43 of the roller 42B and the top surface of the roller 45 (roller conveyance surface). The shielding plate 100 is horizontally provided at a lower position. The shielding plate 100 is a constant lower than the transport surface of the roller transport path 38B not only during the period when the substrate G stays in the chamber 40 but also during the period when the substrate G does not exist in the chamber 40. The space in the chamber 40 is vertically separated at the height position. Here, the intermediate space SP ₂ and the lower space SP ₃ separated in the vertical direction communicate with each other through the openings 100 a and 100 b of the shielding plate 100 and a gap around the shielding plate 100.

Furthermore, the reduced-pressure drying unit 12 of this embodiment is configured such that the gas outlet of the purging gas jet part 80 disposed near the side wall of the chamber 40 is located at a position higher than the roller transport path 38 (most preferably 20 to 20 from the roller transport surface). 30 mm higher position). Thereby, the purging gas ejected from the purging gas ejection unit 80 is the upper space SP ₁ between the ceiling 52 of the chamber 40 and the substrate G, the intermediate space SP ₂ between the substrate G and the shielding plate 100, and the shielding. The lower space SP ₃ between the plate 100 and the bottom surface of the chamber 40 flows separately.

According to such a configuration, the airflow flowing in the chamber 40 during evacuation and purging is in each of the uppermost space SP ₁ , the intermediate space SP ₂ , and the lowermost space SP ₃ separated by the substrate G and the shielding plate 100. Controlled individually, the variation of the atmospheric temperature in the chamber is significantly reduced.

  The inventor selects 13 representative measurement points ch1 to ch13 distributed over the central portion, the intermediate portion, and the peripheral portion in the chamber 40 as shown in FIG. Under the conditions, the following four types of configurations A, B, C, and D were tested for the drying under reduced pressure and the parsing. During this experiment, the atmospheric temperature and pressure in the chamber during vacuum drying treatment and parsing at each representative point were measured, and the maximum temperature Max among the atmospheric temperature characteristics J1 to J13 for 13 locations (ch1 to ch13) was recorded. When the extracted characteristic (Ji) and the characteristic (Jj) recording the minimum temperature Min were extracted and plotted, the results shown in FIGS. 9 to 12 were obtained. In this experiment, the measurement height position of each representative measurement point ch1 to ch13 was selected to be 120 mm from the bottom surface of the chamber 40, and a thermocouple temperature sensor was used.

A: [With shielding plate, purge on transport path] FIG.
Like the said embodiment, it is the structure which provides the shielding board 100 and provides the gas jet nozzle of the purging gas jet part 80 in the position higher than the roller conveyance path 38B.

B: [With shield plate, purge under conveyance path] FIG.
Although the shielding plate 100 is provided as in the above embodiment, the gas jet port of the purging gas jet part 80 is provided at a position lower than the roller transport path 38B (position approximately 100 mm lower than the transport surface). It is a modification (1st modification) of the said embodiment.

C: [No shielding plate, purge on transport path] FIG.
Although the said shielding board 100 is not provided, it is the structure which provides the gas ejection port of the purging gas ejection part 80 in the position higher than the roller conveyance path 38B. This is also a modification (second modification) of the above embodiment.

D: [No shielding plate, purge under conveyance path] FIG.
The shielding plate 100 is not provided, and the gas ejection port of the purging gas ejection part 80 is provided at a position lower than the roller conveyance path 38B (position approximately 100 mm lower than the conveyance surface). This corresponds to the configuration of the prior art.

  As shown in FIG. 9, in the configuration (embodiment) of A above, the minimum value of the atmospheric temperature in the chamber during evacuation is −0.2 ° C., and the maximum value of the atmospheric temperature in the chamber during purging is 32 ° C. The maximum fluctuation range was 32.2 ° C.

  As shown in FIG. 10, in the configuration B, the minimum value of the atmospheric temperature in the chamber during evacuation is −2.0 ° C., and the maximum value of the atmospheric temperature in the chamber during purging is 39.0 ° C. The maximum fluctuation range was 41.0 ° C.

  As shown in FIG. 11, in the above configuration C, the minimum value of the atmospheric temperature in the chamber during evacuation is -15.0 ° C., and the maximum value of the atmospheric temperature in the chamber during purging is 36.7 ° C. The maximum fluctuation range was 51.7 ° C.

  As shown in FIG. 12, in the above configuration D, the minimum value of the atmospheric temperature in the chamber during evacuation is −16.0 ° C., and the maximum value of the atmospheric temperature in the chamber during purging is 49.3 ° C. The maximum fluctuation range was 65.3 ° C.

  Thus, according to the configuration of the above A (embodiment), the maximum fluctuation range of the atmospheric temperature in the chamber can be halved as compared with the configuration of the above D (prior art). Also in the configuration of B (first modification), the maximum fluctuation range of the atmospheric temperature in the chamber can be reduced to about 60% compared to the configuration of D (prior art). Also in the configuration of C (second modification), the maximum fluctuation range of the atmospheric temperature in the chamber can be reduced to about 78% compared to the configuration of D (prior art).

  As an extension of the experiment, the present inventor repeats the vacuum drying treatment / purging process under the same conditions a plurality of times (9 times) at a constant cycle for each of the configurations A, B, C, and D, and each vacuum drying is performed. When the temperature of the lift pin 62 immediately before the start of processing was measured and plotted, the characteristics shown in FIG. 13 were obtained.

  As shown in the figure, according to the configuration of the above A (embodiment), the lift pin temperature at normal temperature (about 25 ° C.) is stabilized for the first time in the range of 26 ° C. to 27 ° C. slightly higher than normal temperature from the second time. be able to.

  Moreover, in the structure of said B (1st modification), lift pin temperature can be stopped in the range of 26 to 27 degreeC at the 2nd time, and can be stabilized in the range of 27 to 28 degreeC after the 3rd time.

  Moreover, in the structure of said C (2nd modification), lift pin temperature can be stabilized in the range of 27 to 28 degreeC from the 2nd time.

  On the other hand, in the configuration of D (prior art), the lift pin temperature gradually increases every time the reduced-pressure drying process / purging process is repeated, and it takes a while for stabilization. Of course, the temperature at the time of stabilization (saturation) becomes considerably high and is close to 30 ° C.

  As described above, according to the embodiment and the modification thereof, the fluctuation range of the atmospheric temperature in the chamber during the reduced-pressure drying process and the parsing can be reduced, and therefore, the thermal influence that each lift pin 62 of the lift mechanism 60 receives from the ambient temperature. As a result, the thermal influence of the substrate G from the lift pins 62 can be reduced, and the transfer of the pin transfer to the resist coating film on the substrate G can be suppressed. Thereby, the film quality of the resist coating film on the substrate G can be improved.

  14 and 15 show the configuration of the reduced pressure drying unit 12 in the second embodiment. In the second embodiment, the substrate lift mechanism (60) is not provided, and instead, a large number of support pins 104 fixed to the upper surface of the shielding plate 100 are discretely attached (for example, in a matrix). The shielding plate elevating mechanism 106 enables the substrate G to be supported by the support pins 104 by raising the tips of the support pins 104 higher than the roller conveyance path 38B when performing the decompression drying process (FIG. 15). When performing the above, the shielding plate 100 is moved up and down (raised and lowered) so that the roller tip of the support pin 104 is lower than the roller conveyance path 38B and the roller conveyance mechanism can convey the substrate (FIG. 14). . In this case, the clearance H is determined by the height (length) of the support pin 104. The backward (lower limit) height position of the shielding plate 100 is set to a position higher than the shaft 43 of the roller 42B and lower than the top surface (roller conveying surface) of the roller 45.

  The shielding plate elevating mechanism 106 connects one or more elevating drive sources, for example, cylinders 108 disposed outside (below) the chamber 40 to the shielding plate 100 via the horizontal support plate 110 and the elevating support shaft 112. Yes. The elevating support shaft 112 passes through the bottom wall of the chamber 40 in an airtight manner via the seal member 114, and the upper end thereof is coupled to the lower surface of the shielding plate 100.

  Also in the second embodiment, similarly to the above-described embodiment, it is possible to reduce the fluctuation range of the atmospheric temperature in the chamber during the vacuum drying process and the parsing, and each support pin 104 on the shielding plate 100 has an atmosphere. It is possible to reduce the thermal influence from the temperature, and thereby reduce the thermal influence that the substrate G receives from the support pins 104, and to prevent the pin transfer trace from being applied to the resist coating film on the substrate G.

  In the above-described embodiment, the fixed (or lower limit) height position of the shielding plate 100 is set to a position higher than the shaft 43 of the roller 42B. However, although the effect of the shielding plate 100 is reduced to some extent, the fixed (or lower limit) height position of the shielding plate 100 can be set at a position slightly lower than the shaft 43 of the roller 42B.

  The chamber 40 of the reduced-pressure drying unit 12 in the above-described embodiment has a configuration in which the substrate G passes through the chamber 40 by providing the carry-in port 44 and the carry-out port 46 on the pair of chamber side walls facing each other in the transport direction (X direction). It was. However, it is also possible to use a structure in which one loading / unloading port provided on one side wall of the chamber 40 serves as both a loading / unloading port. In this case, the loading-side roller conveyance path 38A and the unloading-side roller conveyance path 38C can be shared. It is peeled off.

  The substrate to be processed in the present invention is not limited to a glass substrate for LCD, and other flat panel display substrates, semiconductor wafers, CD substrates, photomasks, printed substrates and the like are also possible. The coating liquid to be dried under reduced pressure is not limited to a resist liquid, and for example, a processing liquid such as an interlayer insulating material, a dielectric material, or a wiring material is also possible.

Claims (8)

A vacuum drying apparatus that performs a vacuum drying process on a film of a coating solution formed on a substrate to be processed,
A depressurizable chamber having a space for accommodating the substrate in a horizontal state;
A roller transport path continuous in and out of the chamber, and a transport mechanism for transporting the substrate into the chamber or transporting the substrate out of the chamber by roller transport on the roller transport path;
An exhaust mechanism for evacuating the chamber in a sealed state for the reduced-pressure drying process;
A buzzing mechanism for supplying a purging gas into the chamber to finish the vacuum drying process;
In order to support the substrate horizontally at the tip of the pin, it has a large number of support pins discretely arranged in the chamber, and when carrying out the vacuum drying process, the tip of the support pin is transported to the roller When the substrate is supported higher than the path, and the substrate is carried in and out, the tip of the support pin is made lower than the roller conveyance path so that the substrate can be conveyed by the conveyance mechanism. A substrate lift mechanism;
A reduced-pressure drying apparatus comprising: a shielding plate provided so as to cover the bottom of the substrate near the roller conveyance path in order to reduce the variation in the atmospheric temperature in the chamber.   The reduced-pressure drying apparatus according to claim 1, wherein the shielding plate is fixedly provided at a certain height position. A vacuum drying apparatus that performs a vacuum drying process on a film of a coating solution formed on a substrate to be processed,
A depressurizable chamber having a space for accommodating the substrate in a horizontal state;
A roller transport path continuous in and out of the chamber, and a transport mechanism for transporting the substrate into the chamber or transporting the substrate out of the chamber by roller transport on the roller transport path;
An exhaust mechanism for evacuating the chamber in a sealed state for the reduced-pressure drying process;
A buzzing mechanism for supplying a purging gas into the chamber to finish the vacuum drying process;
In order to reduce the atmospheric temperature in the chamber during the vacuum drying process and the purging, a shielding plate provided to cover the bottom of the substrate;
A number of support pins discretely provided on the shielding plate to horizontally support the substrate at the tip of the pin during the vacuum drying process;
When coupled with the shielding plate and performing the drying process, the tip of the support pin is made higher than the roller conveyance path so that the substrate can be supported by the support pin, and when the substrate is carried in and out. A reduced-pressure drying apparatus comprising: a shielding plate lifting mechanism that moves the shielding plate up and down so that the tip of the support pin is lower than the roller transportation path so that the substrate can be transported by the transportation mechanism.   The said shielding board has a 1st opening for penetrating the said support pin so that raising / lowering is possible, and a 2nd opening for avoiding interference with the said roller conveyance path. The vacuum drying apparatus according to item.   The reduced-pressure drying apparatus according to any one of claims 1 to 4, wherein the purging mechanism includes a purging gas ejection unit that ejects the purging gas at a position higher than a conveyance surface of the roller conveyance path.   The reduced-pressure drying apparatus according to claim 5, wherein a gas outlet of the purging gas outlet is provided at a position 20 to 30 mm higher than a transfer surface of the roller transfer path. A vacuum drying apparatus that performs a vacuum drying process on a film of a coating solution formed on a substrate to be processed,
A depressurizable chamber having a space for accommodating the substrate in a horizontal state;
An exhaust mechanism for evacuating the chamber in a sealed state for the reduced-pressure drying process;
A roller transport path continuous in and out of the chamber, and a transport mechanism for transporting the substrate into the chamber or transporting the substrate out of the chamber by roller transport on the roller transport path;
In order to support the substrate horizontally at the tip of the pin, it has a large number of support pins discretely arranged in the chamber, and when carrying out the vacuum drying process, the tip of the support pin is transported to the roller When the substrate is supported higher than the path, and the substrate is carried in and out, the tip of the support pin is made lower than the roller conveyance path so that the substrate can be conveyed by the conveyance mechanism. A substrate lift mechanism;
A buzzing mechanism for supplying a purging gas into the chamber to finish the vacuum drying process,
The reduced pressure drying apparatus, wherein the purging mechanism includes a gas ejection unit that ejects the purging gas at a position higher than the roller conveyance path.   The reduced-pressure drying apparatus according to claim 7, wherein a gas outlet of the purging gas outlet is provided at a position 20 mm to 30 mm higher than a transfer surface of the roller transfer path.

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