JP4508436B2 - Coating method and coating apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for forming a film by applying a liquid on a substrate to be processed.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a lithography process in a manufacturing process of an LCD or a semiconductor device, a so-called spin coating method is commonly used or frequently used to apply a resist solution on a substrate to be processed (glass substrate, semiconductor substrate). However, in the conventional general spin coating method, the substrate to be processed is spin-rotated at a considerably high speed, so that a large amount of resist solution is scattered out of the substrate by centrifugal force, which is wasted and causes particles. There is a problem. In addition, when the substrate is enlarged, there is a problem that air turbulence is likely to occur due to the high peripheral speed at the outer periphery of the substrate during spin rotation, and the film thickness of the resist film is likely to fluctuate and thus the resolution is liable to decrease.
[0003]
Therefore, as a new resist coating method that replaces the spin coating method, as shown in FIG. 16, the resist solution R is removed from the resist nozzle 2 by moving the resist nozzle 2 relative to the substrate 1 to be processed vertically or horizontally. A technique (spinless method) has been proposed in which the resist solution R is uniformly applied on the substrate 1 with a desired film thickness without requiring high-speed spin rotation.
[0004]
[Problems to be solved by the invention]
In the conventional spinless method as described above, in order to obtain a resist film having a uniform film thickness from end to end of the substrate 1 to be processed, the discharge port of the resist nozzle 2 is formed with a very small aperture (usually 100 μm or less). The resist solution R must be discharged at a high pressure and at a constant flow rate, and the resist nozzle 2 must be scanned at a constant speed. That is, the film thickness uniformity of the resist film is governed by the fine diameter ejection characteristics and the scanning speed of the resist nozzle 2, and the film thickness uniformity cannot be obtained unless the accuracy of these rule conditions can be realized. There's a problem. Further, even if such high accuracy of the rule conditions can be realized, there is a problem that the coating processing time becomes considerably long and the throughput is lowered.
[0005]
The present invention has been made in view of the above-described problems of the prior art, and provides a coating method and a coating apparatus capable of efficiently forming a coating film having a uniform thickness on a substrate to be processed. With the goal.
[0006]
[Means for Solving the Problems]
  In order to achieve the above object, the coating method of the present invention includes a coating step of applying a predetermined coating solution almost uniformly on a substrate to be processed, and after the coating step,Place the substrate in an atmosphere of high-pressure gas in a sealable processing chamber,And a leveling step in which ultrasonic waves are propagated in or on the surface of the coating liquid on the substrate, and the thickness of the coating liquid film is made uniform by vibration of the ultrasonic waves.
[0007]
  In the coating method of the present invention, the coating solution may be roughly coated almost uniformly on the substrate to be processed in the coating process first. In the next leveling step, each part of the coating liquid on the substrate is oscillated and displaced by ultrasonic waves, so that the irregularities on the surface of the liquid film can be broken and leveled with high accuracy in a short time. In this way, a resist coating film having excellent film thickness uniformity can be formed in a short processing time by sequentially performing two steps of processing steps (coating / leveling).In the leveling step in the coating method of the present invention, the substrate is placed in a high-pressure gas atmosphere and the coating liquid on the substrate is subjected to ultrasonic vibration as described above, thereby drying the coating liquid on the substrate in high-pressure gas. By increasing the fluidity and making the coating liquid spread on the substrate with a static pressure of a high-pressure gas, the leveling effect by ultrasonic vibration can be enhanced and the processing time can be further shortened.
[0008]
In the leveling step of the present invention, as a preferred embodiment, a method of applying ultrasonic vibration propagating from the back side of the substrate in a direction perpendicular to the surface of the substrate, or a coating solution on the substrate parallel to the surface of the substrate from at least one side A method of applying ultrasonic vibration propagating in any direction can be used. In particular, in the method of applying ultrasonic vibration propagating in the direction parallel to the surface of the substrate to the coating liquid on the substrate, the standing wave is formed by superimposing the traveling wave and the reflected wave, thereby applying the coating on the substrate. It is also possible to standardize the surface of the liquid into a minute uneven shape corresponding to the wavelength of the ultrasonic wave.
[0009]
In the leveling step of the present invention, a preferred embodiment for enhancing the leveling effect by ultrasonic vibration and further shortening the processing time is to provide ultrasonic vibration propagating in the direction perpendicular to the surface of the substrate from the back side of the substrate, In this method, ultrasonic vibration propagating in a direction parallel to the surface of the substrate from at least one side surface is applied to the coating liquid on the substrate. In this case, first, the ultrasonic vibrations in both directions are simultaneously applied for a predetermined first time, and then the ultrasonic vibrations in either direction are stopped to improve the leveling finish. Only the ultrasonic vibration in the direction may be applied for a predetermined second time.
[0010]
  The coating apparatus of the present invention has a coating processing unit that applies a predetermined coating solution almost uniformly on a substrate to be processed, and a sealable processing chamber capable of forming an atmosphere of high-pressure gas, and after the coating step, The substrate is placed in an atmosphere of high-pressure gas in the processing chamber, ultrasonic waves are propagated in or on the coating solution on the substrate, and the thickness of the coating solution film is made uniform by vibration of the ultrasonic waves. A leveling processing unit.
[0011]
  In the coating apparatus of the present invention, first, the coating solution may be applied roughly uniformly on the substrate to be processed by the coating processing unit. In the leveling processing section, each part of the coating liquid on the substrate is oscillated and displaced with ultrasonic waves, so that the unevenness on the surface of the liquid film can be broken down and leveled with high accuracy in a short time. In this way, a resist coating film having excellent film thickness uniformity can be formed in a short processing time by sequentially performing two steps of processing steps (coating / leveling). The leveling processing unit makes the coating liquid on the substrate difficult to dry in the high-pressure gas by placing the substrate in a high-pressure gas atmosphere and applying the ultrasonic vibration as described above to the coating liquid on the substrate. By increasing the fluidity and further spreading the coating liquid on the substrate with a static pressure of high-pressure gas, the leveling effect by ultrasonic vibration can be strengthened and the processing time can be further shortened.
[0012]
  Of the present inventionSuitableAccording to one aspect, the leveling processor isIn the processing chamberA stage for placing and supporting the substrate almost horizontally with the coating film facing up, and thisFor the coating solution on the substrate supported by the stageFor applying ultrasonic vibration propagating in the direction perpendicular to the surface of the substrate from the back side of the stageUltrasonic vibration applying meansAnd thisUltrasonic vibration applying meansFor electrically drivingDriving circuitAnd have. In such a configuration,Ultrasonic vibration applying meansFrom the substrate propagates in the coating liquid on the substrate in a direction perpendicular to the surface of the substrate through the stage and the substrate, and each part of the coating liquid is vibrated and displaced in the same direction.
[0013]
  Another of the present inventionOne suitableAccording to the aspect, the leveling processing unitIn the processing chamberA supporting member that supports the substrate by placing the coating solution film upwards substantially horizontally, and an ultra-high propagation property that propagates horizontally from at least one side of the coating solution on the substrate supported by the supporting member. For giving sonic vibrationUltrasonic vibration applying meansAnd thisUltrasonic vibration applying meansFor electrically drivingDriving circuitAnd have. In such a configuration,Ultrasonic vibration applying meansFrom the substrate propagates in the coating liquid on the substrate in a direction parallel to the surface of the substrate from end to end, and each part of the coating liquid is oscillated and displaced in the same direction.
[0014]
In the coating apparatus of the present invention, as a preferred embodiment, the coating processing unit includes a coating liquid discharge unit including a nozzle that discharges a predetermined coating liquid toward the substrate to be processed, and the nozzle on the substrate in a predetermined scanning pattern. It may be configured to have a scanning drive means that moves relatively. In the present invention, since it is sufficient to apply the coating liquid almost uniformly on the substrate to be processed, it is not necessary to demand strict accuracy in the discharge performance and scanning performance of the nozzle.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to FIGS.
[0016]
FIG. 1 shows a coating and developing treatment system as an example of a system in which a coating apparatus according to the present invention can be incorporated. This coating / development processing system is installed in a clean room and uses, for example, an LCD substrate as a substrate to be processed, and performs cleaning, resist coating, pre-baking, developing, and post-baking in the photolithography process in the LCD manufacturing process. is there. The exposure process is performed by an external exposure apparatus (not shown) installed adjacent to this system.
[0017]
This coating and developing system is roughly divided into a cassette station (C / S) 10, a process station (P / S) 12, and an interface unit (I / F) 14.
[0018]
A cassette station (C / S) 10 installed at one end of the system has a cassette stage 16 on which a predetermined number, for example, four cassettes C for storing a plurality of substrates G can be placed, and a cassette C on the stage 16. And a transport mechanism 20 for taking in and out the substrate G. The transport mechanism 20 has a means for holding the substrate G, for example, a transport arm, can be operated with four axes of X, Y, Z, and θ, and is a main transport device on the process station (P / S) 12 side to be described later. 38 and the substrate G can be transferred.
[0019]
The process station (P / S) 12 includes, in order from the cassette station (C / S) 10 side, a cleaning process unit 22, a coating process unit 24, and a development process unit 26, a substrate relay unit 23, a chemical solution supply unit 25, and It is provided in a horizontal row via (spaced) the space 27.
[0020]
The cleaning process unit 22 includes two scrubber cleaning units (SCR) 28, an upper and lower ultraviolet irradiation / cooling unit (UV / COL) 30, a heating unit (HP) 32, and a cooling unit (COL) 34. Contains.
[0021]
The coating process unit 24 includes a resist coating unit (CT) 40, a vacuum drying unit (VD) 42, an edge remover unit (ER) 44, an upper and lower two-stage adhesion / cooling unit (AD / COL) 46, An upper and lower two-stage heating / cooling unit (HP / COL) 48 and a heating unit (HP) 50 are included.
[0022]
The development process unit 26 includes three development units (DEV) 52, two upper and lower two-stage heating / cooling units (HP / COL) 55, and a heating unit (HP) 53.
[0023]
Conveying paths 36, 52, and 58 are provided in the longitudinal direction at the center of each of the process units 22, 24, and 26, and the main conveying devices 38, 54, and 60 move along the respective conveying paths, and each of the process units 22 The unit is accessed to carry in / out or carry the substrate G. In this system, in each process unit 22, 24, 26, a spinner system unit (SCR, CT, DEV, etc.) is arranged on one side of the transport paths 36, 52, 58, and heat treatment or Irradiation processing units (HP, COL, UV, etc.) are arranged.
[0024]
The interface unit (I / F) 14 installed at the other end of the system is provided with an extension (substrate transfer unit) 57 and a buffer stage 56 on the side adjacent to the process station 12, and is transported to the side adjacent to the exposure apparatus. A mechanism 59 is provided.
[0025]
FIG. 2 shows a processing procedure in this coating and developing processing system. First, in the cassette station (C / S) 10, the transport mechanism 20 takes out one substrate G from a predetermined cassette C on the stage 16, and the main of the cleaning process unit 22 of the process station (P / S) 12. It is transferred to the conveying device 38 (step S1).
[0026]
In the cleaning process section 22, the substrate G is first sequentially carried into an ultraviolet irradiation / cooling unit (UV / COL) 30, subjected to dry cleaning by ultraviolet irradiation in the upper ultraviolet irradiation unit (UV), and then cooled in the lower stage. The unit (COL) is cooled to a predetermined temperature (step S2). This ultraviolet irradiation cleaning removes organic substances on the substrate surface. Thereby, the wettability of the substrate G is improved, and the cleaning effect in the scrubbing cleaning in the next step can be enhanced.
[0027]
Next, the substrate G is subjected to a scrubbing cleaning process by one of the scrubber cleaning units (SCR) 28 to remove particulate dirt from the substrate surface (step S3). After the scrubbing cleaning, the substrate G is subjected to dehydration treatment by heating in the heating unit (HP) 32 (step S4), and then cooled to a constant substrate temperature by the cooling unit (COL) 34 (step S5). Thus, the pretreatment in the cleaning process unit 22 is completed, and the substrate G is transferred to the coating process unit 24 by the main transfer device 38 via the substrate transfer unit 23.
[0028]
In the coating process unit 24, the substrate G is first sequentially loaded into an adhesion / cooling unit (AD / COL) 46, and undergoes a hydrophobic treatment (HMDS) in the first adhesion unit (AD) (step S6). The cooling unit (COL) cools to a constant substrate temperature (step S7).
[0029]
Thereafter, the substrate G is coated with a resist solution by a resist coating unit (CT) 40, and then subjected to a drying process by a reduced pressure drying unit (VD) 42, and then an edge remover unit (ER) 44 of the periphery of the substrate. Excess (unnecessary) resist is removed (step S8).
[0030]
Next, the substrate G is sequentially carried into the heating / cooling unit (HP / COL) 48, and the first heating unit (HP) performs baking after coating (pre-baking) (step S9), and then the cooling unit ( COL) to cool to a constant substrate temperature (step S10). In addition, the heating unit (HP) 50 can also be used for baking after this application | coating.
[0031]
After the coating process, the substrate G is transported to the interface unit (I / F) 14 by the main transport device 54 of the coating process unit 24 and the main transport device 60 of the development process unit 26, and is passed from there to the exposure apparatus. (Step S11). In the exposure apparatus, a predetermined circuit pattern is exposed on the resist on the substrate G. After the pattern exposure, the substrate G is returned from the exposure apparatus to the interface unit (I / F) 14. The transport mechanism 59 of the interface unit (I / F) 14 passes the substrate G received from the exposure apparatus to the development process unit 26 of the process station (P / S) 12 via the extension 57 (step S11).
[0032]
In the development process section 26, the substrate G is subjected to development processing in any one of the development units (DEV) 52 (step S12), and then sequentially carried into one of the heating / cooling units (HP / COL) 55, Post baking is performed in the first heating unit (HP) (step S13), and then the substrate is cooled to a constant substrate temperature in the cooling unit (COL) (step S14). A heating unit (HP) 53 can also be used for this post-baking.
[0033]
The substrate G that has undergone a series of processing in the development process section 26 is returned to the cassette station (C / S) 10 by the transfer devices 60, 54, and 38 in the process station (P / S) 24, where the transfer mechanism 20 Is stored in one of the cassettes C (step S1).
[0034]
In this coating and developing treatment system, the present invention can be applied to the resist coating unit (CT) 40 of the coating process unit 24. Hereinafter, an embodiment in which the present invention is applied to a resist coating unit (CT) 40 will be described with reference to FIGS.
[0035]
3 and 4 show the configuration of the main parts of the resist coating unit (CT) 40, the reduced pressure drying unit (VD) 42, and the edge remover unit (ER) 44 in the coating process unit 12. FIG.
[0036]
These coating system processing unit groups (CT) 40, (VD) 42, and (ER) 44 are arranged in a horizontal row on the support base 60 in the order of processing steps. A set or a plurality of sets of transfer arms 64, 64 that move along a pair of guide rails 62, 62 laid on both sides of the support base 60 directly place the substrate G between these units (on the main transfer path 52 side). Exchanges (without going through the main transport device 54).
[0037]
In this embodiment, the resist coating unit (CT) 40 equalizes (levels) the coating processing unit 66 for coating the resist solution almost uniformly on the substrate G and the film thickness of the resist coating film on the substrate G. And a leveling processing unit 68. The configuration and operation of both processing units 66 and 68 will be described in detail later.
[0038]
The vacuum drying unit (VD) 42 includes a tray or shallow container type lower chamber 70 whose upper surface is open, and a lid-shaped upper chamber configured to be tightly fitted or fitted to the upper surface of the lower chamber 70. 72. The lower chamber 70 is substantially rectangular, and stages 74 for placing and supporting the substrate G horizontally are arranged at the center, and exhaust ports 76 are provided at the four corners of the bottom surface. An exhaust pipe 78 connected to each exhaust port 76 from below the lower chamber 70 communicates with a vacuum pump (not shown). With the lower chamber 70 covered with the upper chamber 72, the processing space in both the chambers 70, 72 can be depressurized to a predetermined degree of vacuum by the vacuum pump.
[0039]
The edge remover unit (ER) 44 includes a stage 80 for horizontally placing and supporting the substrate G, alignment means 82 for positioning the substrate G at a pair of opposite corners, and four sides of the substrate G. There are provided four remover heads 84 and the like for removing excess resist from the peripheral edge (edge). With the alignment means 82 positioning the substrate G on the stage 80, each remover head 84 moves along each side of the substrate G, and removes excess resist adhering to the peripheral portion of each side of the substrate with a thinner. It dissolves and is removed.
[0040]
The coating processing unit 66 of the resist coating unit (CT) 40 can be moved up and down for placing and holding the substrate G horizontally in the processing container 86 and a cup-shaped processing container 86 whose upper surface is open. A stage 88, an elevating drive unit 90 provided below the processing container 86 for elevating the stage 88, and a resist nozzle 92 for discharging a resist solution to the substrate G on the stage 88 in the XY directions. It has a nozzle scanning mechanism 94 for driving, and a controller (not shown) for controlling each part.
[0041]
FIG. 5 shows the configuration of the nozzle scanning mechanism 94. In this nozzle scanning mechanism 94, a pair of Y guide rails 96, 96 extending in the Y direction are disposed on both sides of the processing container 86 (not shown in FIG. 5), and the X direction is between the Y guide rails 96, 96. An X guide rail 98 extending in the Y direction is bridged so as to be movable in the Y direction. A Y-direction drive unit 100 disposed at a predetermined position, for example, at one end of the Y guide rail 96 on one side moves the X guide rail 98 along the Y guide rails 96 and 96 via a transmission mechanism (not shown) such as an endless belt. And is driven in the Y direction. Further, a carriage (conveyance body) 102 that can move in the X direction along the X guide rail 98 in, for example, a self-propelled type or an externally driven type is provided, and a resist nozzle 92 is attached to the carriage 102. The resist nozzle 92 includes one or a plurality of resist solution introduction units that introduce a resist solution from a resist solution supply unit (not shown) and a fine diameter (for example, about 100 to 200 μm) that discharges the introduced resist solution vertically downward. Individual discharge ports.
[0042]
3 and 4, the leveling processing unit 68 of the resist coating unit (CT) 40 is placed on the stage 104 that horizontally places and supports the substrate G at a predetermined height position, and the stage 104. A vertical ultrasonic vibration applying means 106 and a horizontal ultrasonic vibration applying means 108 for applying vertical and horizontal ultrasonic vibrations to the coating liquid on the substrate G, respectively, and a controller (not shown) for controlling each part. ). The stage 104 may be made of a material that easily propagates ultrasonic vibration, such as a metal plate, and has a substrate mounting surface that is slightly larger than the substrate G. The legs 104 a that horizontally support the stage 104 may be fixed or installed on the support base 60.
[0043]
The vertical ultrasonic vibration applying unit 106 includes one or a plurality of ultrasonic vibrators 110 disposed on the back side of the stage 104, and a drive circuit (not shown) for electrically driving each ultrasonic vibrator 110. ). Each ultrasonic vibrator 110 is formed of, for example, a magnetostrictive vibrator or a piezoelectric vibrator, and the vibration surface is brought into close contact with the back surface of the stage 104 so as to generate a longitudinal wave ultrasonic wave having a predetermined frequency vertically upward. It has become.
[0044]
As clearly shown in FIG. 6, the horizontal ultrasonic vibration applying unit 108 includes an ultrasonic vibration body 112 and a substrate pressing portion 114 that are respectively disposed at the left and right ends of the stage 104.
[0045]
The ultrasonic vibrator 112 is a rectangular cylinder extending from end to end in parallel with the left side of the stage 104, and is disposed on the stage 104 so as to be slidable in a horizontal direction perpendicular to the longitudinal direction. The side surface 112a near the stage center of the rectangular cylinder is made of a material that easily propagates ultrasonic vibration, such as a metal plate, and one or a plurality of ultrasonic transducers 116 (FIGS. 8 and 8) are provided on the back side of the vibration transmission plate 112a. 9, FIG. 10). Each ultrasonic transducer 116 is made of, for example, a magnetostrictive transducer or a piezoelectric transducer, and has a vibration surface in close contact with the back surface of the vibration transmission plate 112a so as to generate longitudinal ultrasonic waves having a predetermined frequency in the horizontal direction. It has become. A spring receiving member 118 extending in parallel with the ultrasonic vibrating body 112 is provided at the left end edge of the stage 104, and a plurality of elements are provided with an appropriate interval between the spring receiving member 118 and the ultrasonic vibrating body 112. The compression coil spring 120 is provided.
[0046]
The substrate pressing portion 114 has a pressing member 122 having a U-shaped cross section extending from end to end in parallel with the right side of the stage 104, and the groove portion of the pressing member 122 slides horizontally on the right end portion of the stage 104. It is movably fitted. A supporting member 124 made of a vertical plate or a vertical shaft is coupled to the lower surface of the pressing member 122, and a horizontal pressing driving unit (not shown) including a cylinder or a motor provided in the driving unit 126 is interposed via the supporting member 124. Thus, the pressing member 122 can be moved in the horizontal direction perpendicular to the longitudinal direction.
[0047]
As shown in FIGS. 3 and 6, the stage 104 is formed with a plurality of through holes 104b at appropriate intervals for allowing the lift pins 125 (FIG. 13) for raising and lowering the substrate to pass up and down. An elevating drive unit (not shown) for raising and lowering the lift pin 125 is also provided in the drive unit 126.
[0048]
Next, the operation of the resist coating unit (CT) 40 of this embodiment will be described.
[0049]
First, the substrate G before the coating process is carried into the coating processing unit 66 by the main transporting device 54 (FIG. 1) on the main transport path 52 side. In the coating processing unit 66, the stage 88 is lifted up to a position where the stage 88 comes out from the upper surface opening of the processing container 86 by the elevation driving unit 90, and the substrate G is transferred onto the stage 88 by the main transfer device 54. In order to hold the substrate G, for example, a vacuum suction means (not shown) may be provided on the upper surface of the stage 88.
[0050]
When the substrate G is placed on the stage 88, the stage 88 is then lowered to a predetermined position in the processing container 86 by the elevating drive unit 90, and the resist coating process for the substrate G is executed at that position.
[0051]
More specifically, upon receiving the supply of the resist solution from the resist solution supply unit, the resist nozzle 92 discharges the resist solution toward the substrate G at a predetermined pressure and flow rate, and at the same time, the nozzle scanning mechanism 94 moves the resist nozzle 92 to XY. Scan vertically and horizontally in the direction. For example, scanning may be performed from end to end of the substrate G with a right-angle zigzag scanning pattern as in FIG. As a result, the traces of the resist solution dripping are formed on the substrate G along the scanning pattern, that is, along the movement path of the resist nozzle 92. As shown in FIG. By connecting in the width direction, a resist solution film RB is formed so as to cover the entire upper surface (surface to be processed) of the substrate G.
[0052]
Here, the film thickness Dc of the resist liquid film RB formed on the substrate G does not have to be uniform or constant. This is because the film thickness can be made uniform in the next leveling processing unit 68. Therefore, it is not necessary for the coating processing unit 66 to require a very strict accuracy in the mechanism and control for maintaining the discharge pressure or flow rate and scanning speed of the resist nozzle 92 constant.
[0053]
In addition, as will be described later, the leveling processing unit 68 maintains the resist solution on the substrate G almost completely (that is, without throwing away a part of the resist solution to the outside of the substrate). Since it is uniform, the coating processing unit 66 can set the film thickness Dc of the resist liquid film RB in the vicinity of the final target film thickness Ds, and the consumption of the resist liquid can be minimized.
[0054]
When the resist coating process is completed in the coating processing unit 66, the stage 88 is lifted to a position higher than the upper surface opening of the processing container 86 by the elevating drive unit 90. Immediately thereafter, the transfer arms 64 and 64 receive the substrate G from the stage 88 and transfer it to the adjacent leveling processing unit 68.
[0055]
In the leveling processing unit 68, the lift pins 125 protrude upward from the through holes 104b of the stage 104, receive the substrate G from the transfer arms 64 and 64 at the tip of the pin, and then descend while keeping the substrate G in a horizontal posture. Then, the lift pin 125 is lowered until the tip of the pin sinks into the through hole 104 b of the stage 104, and the substrate G is placed on the stage 104.
[0056]
At this time, as shown in FIG. 8, the pressing member 122 of the substrate pressing portion 114 is at a predetermined position (original position) farthest from the central portion on the stage 104, and the substrate G has the ultrasonic vibrators 112 on both the left and right sides. And the pressing surface 122a of the pressing member 122 are placed on the stage 104 so as to leave some gaps PL, PR.
[0057]
After the substrate G is placed on the stage 104, the horizontal ultrasonic wave driving unit in the driving unit 126 operates in the horizontal ultrasonic vibration applying unit 108, and the pressing member 122 of the substrate pressing unit 114 is moved to the center side of the stage 104. Move horizontally by a predetermined distance (to the left in FIG. 8). The horizontal movement of the pressing member 122 causes the substrate G on the stage 104 to move horizontally to the opposite side (left side) while being pressed from one side (right side) by the pressing surface 122 a of the pressing member 122, so that the ultrasonic vibrator 112. The pressure is brought into contact with the vibration transmission plate 112a. The ultrasonic vibrator 112 is moved backward by a predetermined distance by the pressing force F from the substrate G side while receiving the elastic repulsive force of the compression coil spring 120 from the back. In this way, as shown in FIG. 9, the substrate G is fixed and held on the stage 104 so as to be sandwiched from both the left and right sides by the ultrasonic vibrator 112 and the pressing member 122.
[0058]
Next, the vertical ultrasonic vibration applying means 106 and the horizontal ultrasonic vibration applying means 108 are applied to the resist liquid film RB on the substrate G fixed and held on the stage 104 as described above, respectively in the vertical direction and the horizontal direction. The ultrasonic vibration propagating to is applied in a predetermined sequence.
[0059]
As one aspect of the ultrasonic vibration application sequence in the present embodiment, first, horizontal ultrasonic vibration by the horizontal ultrasonic vibration applying means 108 is applied for a predetermined first time, and then the vertical ultrasonic vibration applying means 106 is applied. The ultrasonic vibration in the vertical direction may be applied for a predetermined second time.
[0060]
When the ultrasonic vibrator 116 in the ultrasonic vibrator 112 generates or excites ultrasonic waves in the horizontal ultrasonic vibration applying means 108, as shown in FIG. 10, the longitudinal ultrasonic wave USh from the ultrasonic vibrator 116 is generated. The light enters the resist liquid film RB on the substrate G from the left side via the vibration transmission plate 112a, and propagates in the resist liquid film RB in the horizontal direction from the left end to the right end. By this horizontal ultrasonic wave propagation, each part of the resist liquid film RB is oscillated and displaced left and right, so that the vicinity of the surface of the liquid film is flattened to some extent so that the uneven part is broken. However, if this horizontal ultrasonic wave propagation or vibration is continued for too long, the surface of the resist liquid film RB may be swelled. Therefore, the first time is set to an appropriate length, and the vertical ultrasonic vibration is set. Switching to vertical ultrasonic wave propagation (vibration) by the applying means 106 may be performed.
[0061]
When the ultrasonic transducer 110 generates or excites an ultrasonic wave in the vertical ultrasonic vibration applying unit 106, the longitudinal ultrasonic wave USv from the ultrasonic transducer 110 passes through the stage 104 and the substrate G as shown in FIG. Then, the light enters the resist liquid film RB on the substrate G from the bottom surface and propagates in the resist liquid film RB in the vertical direction from the bottom to the surface. Due to this vertical ultrasonic wave propagation, each part of the resist liquid film RB is vertically displaced, so that the surface of the liquid film RB can be further flattened without causing undulation. Note that the frequencies of the ultrasonic waves USv and USh by the ultrasonic transducers 110 and 116 may be the same or different.
[0062]
As another aspect of the ultrasonic vibration application sequence in this embodiment, first, the horizontal ultrasonic vibration by the horizontal ultrasonic vibration applying means 108 and the vertical ultrasonic vibration by the vertical ultrasonic vibration applying means 106 are simultaneously applied simultaneously. The method of doing is also effective. According to this simultaneous application method, the ultrasonic waves USh and USv as described above are simultaneously propagated to the resist liquid film RB on the substrate G in the horizontal direction and the vertical direction, respectively, so that each part of the resist liquid film RB is randomly generated. It is possible to vibrate and displace with a strong power in any direction, and to flatten the uneven portion on the surface of the liquid film in a shorter time. Then, for flat finishing, one of the ultrasonic vibrations in both directions may be stopped and only the other may be left after a predetermined time has elapsed. When the ultrasonic vibration in the vertical direction is stopped and the ultrasonic vibration in the horizontal direction is left, the remaining application time, the amplitude of the ultrasonic wave USh, the sound pressure, etc. are appropriately set so as not to cause swell on the surface of the resist liquid film RB. It's okay.
[0063]
As described above, the resist liquid film RB on the substrate G is leveled by the ultrasonic vibration in the horizontal direction and the vertical direction, so that the resist having the set film thickness Ds with excellent film thickness uniformity as shown in FIG. It becomes a coating film.
[0064]
When the leveling processing section 68 completes the above leveling processing, the horizontal ultrasonic vibration applying means 108 moves the pressing member 122 of the substrate pressing section 114 horizontally to the outside (right end side) of the stage 104 and returns to the original position. . Then, on the opposite side (left end side) of the stage 104, the ultrasonic vibrator 112 returns to the original position while pushing the substrate G to the right by the elastic return force of the compression coil spring 120. Thereafter, as shown in FIG. 13, the lift pins 125 protrude above the through holes 104 b of the stage 104 and lift the substrate G to a predetermined height position in a horizontal posture. Immediately thereafter, the transfer arms 64 and 64 receive the substrate G from the lift pins 125 and transfer it to the adjacent vacuum drying unit (VD) 42.
[0065]
As described above, in the resist coating unit (CT) 40 of this embodiment, the coating liquid is first applied almost uniformly on the substrate G by the coating processing unit 66, and then the leveling processing unit 68 on the substrate G. The resist liquid film is leveled by ultrasonic vibration.
[0066]
In this way, a resist having excellent film thickness uniformity in a shorter processing time than the conventional spinless method (FIG. 16) by sequentially performing two processing steps (coating / leveling) in the two processing units 66 and 68. A coating film can be formed. In particular, in the coating process, since it is not necessary to obtain strict accuracy in the discharge performance and scanning performance of the resist nozzle 92, the mechanism can be simplified and the operation speed can be increased. Further, in the leveling process, the resist liquid film on the substrate G can be leveled to a highly accurate flat surface in a short time by using both the horizontal ultrasonic vibration and the vertical ultrasonic vibration in combination. This makes it possible to avoid or erase so-called transfer marks from the resist coating film.
[0067]
In the coating processing unit 66 of the above-described embodiment, a scanning method is used in which the resist nozzle 92 is moved in the XY direction with respect to the stationary substrate G placed on the table 86. However, other scanning methods, for example, a method in which the resist nozzle 92 side is fixed and the table 86 side is moved in the XY directions are possible, or the resist nozzle 92 is moved in the radial direction of the rotation circle while the substrate G is rotated. It is also possible to use such a method. The configuration of the resist nozzle 92 can be various types, and the shape and number of the discharge ports are not particularly limited. For example, an elongated slit type is also possible.
[0068]
In the leveling processing unit 68 of the above embodiment, the horizontal ultrasonic vibration applying unit 108 applies the longitudinal ultrasonic wave USh to the resist liquid film RB on the substrate G from one side surface (left side surface). In this case, the ultrasonic wave USh radiated from the ultrasonic transducer 116 propagates rightward in the resist liquid film RB on the substrate G, and is reflected by the pressing surface 122a of the pressing member 122 or the outer surface of the pressing member 122. The light again enters the resist liquid film RB on the substrate G from the right side surface and propagates to the left. By superimposing such reflected wave ultrasonic waves USh with traveling wave ultrasonic waves USh, it is possible to form ultrasonic standing waves USH in the resist liquid film RB as shown in FIG. It is. Then, by vibrating and displacing each part of the resist liquid film RB with such a standing wave USH, the surface of the liquid film is made fine according to the period or wavelength of the standing wave USH as shown in FIG. It is also possible to standardize the concavo-convex shape to make a substantially flat surface.
[0069]
However, a configuration in which horizontal ultrasonic vibrations are sequentially or simultaneously applied from a plurality of side surfaces to the resist liquid film RB on the substrate G is also possible. In addition, although the leveling characteristic is lower than that in the above embodiment, a configuration including or using only one of the vertical ultrasonic vibration applying unit 106 and the horizontal ultrasonic vibration applying unit 108 is also possible.
[0070]
In the leveling processing unit 68 of the above embodiment, ultrasonic vibration is applied to the resist liquid film RB on the substrate G in the atmosphere. However, a method of applying ultrasonic vibration by placing the resist liquid film RB on the substrate G in an atmosphere of high-pressure gas is also effective. That is, the resist liquid film RB is heated and easily dried by the ultrasonic vibration. Therefore, by setting the pressure around the substrate G to a pressure higher than the atmospheric pressure, the resist liquid film RB is difficult to dry, the viscosity is prevented or reduced, the fluidity is increased, and the film thickness is uniform. Can be improved. In this case, the application of high-pressure gas pressure to the surface of the resist liquid film RB on the substrate G further promotes the uniformity of the film thickness.
[0071]
FIG. 15 shows a configuration example of an apparatus that performs ultrasonic vibration type leveling processing in an atmosphere of high-pressure gas as described above. In this configuration example, a processing unit corresponding to the leveling processing unit 68 in the above-described embodiment is arranged in the sealable processing chamber 130, and an atmosphere of high-pressure gas or A processing space is formed. The high-pressure gas supply unit 132 can be composed of a gas supply source and a gas compression device (for example, a compressor). The high pressure gas may be air, but may be an inert gas. The high-pressure gas from the high-pressure gas supply unit 132 is introduced into the buffer chamber 136 provided at the bottom of the room through the gas supply pipe 134, and the air flow is more uniform and stable than the perforated plate 138 attached to the upper surface of the buffer chamber 136. It is supplied to the processing space on the substrate G. For example, a heating type drying means (not shown) may be provided in the processing chamber 130 and the drying process may be performed following the leveling process. An opening / closing valve 140 may be provided in the gas supply pipe 134. Further, an exhaust means (not shown) such as a vacuum pump is connected to the processing chamber 130 through an exhaust pipe 142 so that the exhaust or gas replacement in the room can be performed. The exhaust pipe 142 may also be provided with an opening / closing valve 144. The processing chamber 130 may have a sealed chamber structure in which a substrate doorway 146 that can be opened and closed is provided on a side wall, for example. A pressure sensor (not shown) can be provided in the processing chamber 130, and the output signal (pressure detection signal) can be fed back to a controller (not shown).
[0072]
The processing chamber 130 in the apparatus configuration of FIG. 15 is configured as a high-pressure gas chamber having a processing space with a constant volume. However, an apparatus configuration that compresses the gas in the space until it becomes a high-pressure gas at a set pressure by reducing the processing space to a predetermined ratio so that the volume of the indoor space or the processing space can be changed while maintaining the airtightness. It is also possible.
[0073]
In addition, although the mechanism is complicated, an apparatus configuration in which not only the leveling process but also the coating process of the previous process is possible in one processing chamber or main body.
[0074]
Although the above-described embodiment relates to a resist coating method and apparatus in a coating and developing processing system for LCD manufacturing, the present invention is applicable to any application that supplies a coating liquid onto a substrate to be processed. As the coating solution in the present invention, in addition to the resist solution, liquids such as an interlayer insulating material, a dielectric material, and a wiring material can be used. The substrate to be processed in the present invention is not limited to an LCD substrate, but may be a semiconductor wafer, a CD substrate, a glass substrate, a photomask, a printed substrate, or the like.
[0075]
【The invention's effect】
As described above, according to the coating method or the coating apparatus of the present invention, a coating film having a uniform film thickness can be efficiently formed on a substrate to be processed.
[Brief description of the drawings]
FIG. 1 is a plan view showing a configuration of a coating and developing processing system to which a substrate processing apparatus of the present invention can be applied.
FIG. 2 is a flowchart showing a processing procedure in the coating and developing treatment system of the embodiment.
FIG. 3 is a plan view illustrating a configuration of a main part of a coating system processing unit group in the coating and developing processing system according to the embodiment.
FIG. 4 is a front view showing a configuration of a main part of a coating system processing unit group in the coating and developing processing system of the embodiment.
FIG. 5 is a perspective view illustrating a configuration of a nozzle scanning mechanism included in a coating processing unit of the resist coating unit according to the embodiment.
FIG. 6 is a perspective view illustrating a configuration of a main part of a leveling processing unit of the resist coating unit according to the embodiment.
FIG. 7 is a schematic cross-sectional view schematically showing a coating film on a substrate obtained by the coating processing unit of the embodiment.
FIGS. 8A and 8B are a schematic plan view and a schematic front view showing one stage of operation of the leveling processing unit of the embodiment. FIGS.
FIGS. 9A and 9B are a schematic plan view and a schematic front view showing one stage of the operation of the leveling processing unit of the embodiment. FIGS.
FIG. 10 is a diagram illustrating an action of propagating horizontal ultrasonic vibrations to the resist liquid film on the substrate in the leveling processing unit of the embodiment.
FIG. 11 is a diagram illustrating an action of propagating ultrasonic vibration in the vertical direction to the resist liquid film on the substrate in the leveling processing unit of the embodiment.
FIG. 12 is a schematic cross-sectional view schematically showing a coating film on a substrate obtained by the leveling processing unit of the embodiment.
FIG. 13 is a schematic cross-sectional view showing a substrate carry-out stage after processing in the leveling processing unit of the embodiment.
FIG. 14 is a diagram illustrating a method for flattening the film thickness by forming an ultrasonic standing wave in the resist liquid film on the substrate in the leveling processing unit of the embodiment.
FIG. 15 is a diagram illustrating a configuration example of an apparatus for applying ultrasonic vibration by placing a resist liquid film on a substrate in a high-pressure gas atmosphere in the leveling processing unit of the embodiment.
FIG. 16 is a perspective view schematically showing a resist coating process by a conventional spinless method.
[Explanation of symbols]
40 resist coating unit (CT)
64 Transfer arm
66 Application processing section
68 Leveling processor
88 stages
92 resist nozzle
94 Nozzle scanning mechanism
104 stages
106 Vertical ultrasonic vibration applying means
108 Horizontal ultrasonic vibration applying means
110 Ultrasonic vibrator
112 Ultrasonic vibrator
114 Substrate pressing part
116 Ultrasonic vibrator
126 Drive unit

Claims (13)

A coating process for almost uniformly coating a predetermined coating solution on the substrate to be treated;
After the coating step, the substrate is placed in a high-pressure gas atmosphere in a process chamber that can be sealed , and ultrasonic waves are propagated in or on the coating liquid on the substrate, and the coating is performed by vibration of the ultrasonic waves. And a leveling step for making the thickness of the liquid film uniform. In the leveling step, to ultrasonic vibrations propagating from the back side of the substrate in a direction perpendicular to the plane of the substrate, coating method of claim 1. In the leveling step, to ultrasonic vibrations propagating from at least one side in a direction parallel to a plane of the substrate relative to the coating solution on the substrate, coating method of claim 1. The leveling step includes
Applying ultrasonic vibration propagating in a direction perpendicular to the surface of the substrate from the back side of the substrate;
And a step of applying ultrasonic vibration propagating from at least one side with respect to the coating solution on said substrate in a direction parallel to a plane of the substrate, coating method of claim 1. 5. The coating method according to claim 3 , wherein in the leveling step , the standing wave of the ultrasonic wave is formed in or on the surface of the coating liquid on the substrate. In the leveling step , ultrasonic vibration propagating from the back side of the substrate in a direction perpendicular to the surface of the substrate is applied, and at the same time, the coating liquid on the substrate is propagated in a direction parallel to the surface of the substrate from at least one side surface. The coating method according to claim 1, wherein ultrasonic vibration is applied. The coating method according to any one of claims 1 to 6, wherein, in the leveling step, the high-pressure gas is introduced into the processing chamber with a uniform air flow through a buffer chamber and a porous plate. In the leveling step, the volume of the processing space is reduced while the processing space of the processing chamber is maintained airtight, and the gas in the processing space is compressed until the high-pressure gas at a set pressure is reached. The coating method according to one item. A coating processing unit for applying a predetermined coating solution almost uniformly on a substrate to be processed;
A sealing chamber capable of forming a high-pressure gas atmosphere, and after the coating step, the substrate is placed in a high-pressure gas atmosphere in the processing chamber, so that the substrate is superficially in or over the coating liquid on the substrate. A leveling processing unit that propagates a sound wave and uniformizes the thickness of the coating liquid film by the vibration of the ultrasonic wave. The leveling processing unit
A stage for placing and supporting the substrate substantially horizontally with the coating solution film facing upward in the processing chamber ;
Ultrasonic vibration applying means for applying ultrasonic vibration propagating in a direction perpendicular to the surface of the substrate from the back side of the stage to the coating liquid on the substrate supported by the stage ;
The coating apparatus according to claim 9, further comprising: a drive circuit for electrically driving the ultrasonic vibration applying unit . The leveling processing unit
A support member for placing and supporting the substrate substantially horizontally with the coating solution film facing upward in the processing chamber ;
Ultrasonic vibration applying means for applying ultrasonic vibration propagating in a horizontal direction from at least one side surface to the coating liquid on the substrate supported by the support member;
The coating apparatus according to claim 9, further comprising: a drive circuit for electrically driving the ultrasonic vibration applying unit . The leveling processing unit
A high-pressure gas supply unit for supplying the high-pressure gas into the processing chamber;
A buffer chamber for temporarily storing the high-pressure gas sent from the high-pressure gas supply unit immediately before introducing the high-pressure gas into the processing chamber;
A perforated plate for supplying the high-pressure gas from the buffer chamber into the processing chamber in a uniform air flow;
The coating apparatus according to any one of claims 9 to 11, which has The application processing unit
Coating liquid discharge means including a nozzle for discharging a predetermined coating liquid toward the substrate to be processed;
Wherein and a scanning drive means for relatively moving the nozzle in a predetermined scan pattern on a substrate, the coating apparatus according to any one of claims 9-12.

Images