JP4353626B2 - Coating method and coating apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for forming a coating 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. 21, the resist solution R is made finer from the resist nozzle 2 while moving or scanning the resist nozzle 2 on the substrate 1 to be processed, for example, in a right-angle zigzag pattern. There has been proposed a technique (spinless method) in which the resist solution R is uniformly applied on the substrate 1 with a desired film thickness without being required to rotate at a high speed by continuously discharging in a linear shape with a diameter. . The resist nozzle 2 used in the spinless method has a discharge port with a very small diameter (for example, about 100 μm), and is configured to discharge the resist solution R at a considerably high pressure.
[0004]
[Problems to be solved by the invention]
In the spinless method as described above, in order to form a resist film having a uniform film thickness from end to end of the substrate 1 to be processed, the supply (discharge) rate of the resist solution R from the resist nozzle 2 is set at least on the substrate 1. Must be continuous and constant. For this reason, as shown in FIG. 21, the resist nozzle 2 is set to have a scanning range larger than that of the substrate 1, and the resist solution is also temporarily removed from the substrate 1 near the return of each line scan. R is continuously discharged. However, the resist solution R discharged outside the substrate 1 is discarded after being received by a resist receiving unit or a collecting unit (not shown) arranged around the substrate and is wasted.
[0005]
Further, a coating film having a uniform film thickness is obtained over the entire surface of the substrate 1 by continuously or connecting the coating lines of the resist solution R supplied in a thin line shape on the substrate 1 at a pitch across the line width direction. Therefore, the total scanning distance of the resist nozzle 2 is considerably long, and therefore the total scanning time, that is, the coating processing time is also considerably long. For this reason, there is a problem that it is difficult to improve the throughput.
[0006]
Furthermore, since the discharge port of the resist nozzle 2 is very small and easily clogs, there is a problem that maintenance is troublesome.
[0007]
The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a coating method that simultaneously realizes improvement of coating liquid consumption efficiency and shortening of processing time in coating processing. .
[0008]
Another object of the present invention is to provide a coating method capable of efficiently forming a high-quality coating film having a uniform film thickness even on a large substrate to be processed.
[0009]
Another object of the present invention is to provide a coating method that relaxes the fine-diameter discharge conditions in the coating method in which the coating liquid is discharged in the form of thin lines, and thus facilitates the design and maintenance of nozzles and the like.
[0010]
Another object of the present invention is to provide a coating apparatus suitable for carrying out the coating method of the present invention.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the coating method of the present invention performs spin rotation on a substrate to be processed at a first rotational speed, while the substrate is being spun on the substrate. From the boundary to the center point of the substrate A first step of supplying and applying a predetermined coating solution, and after the first step, the substrate is spin-rotated at a second rotation speed higher than the first rotation speed; Utilizing centrifugal force from inside to outside of the pre-application area Coating liquid Radially Spread On the substrate And a second step of forming a coating film having a substantially uniform film thickness.
[0012]
Of the present invention In the coating method, a coating process for a substrate to be processed is configured by two steps (first and second steps). In the first step (pre-coating step), the coating liquid is applied to the pre-coating region on the substrate while spinning the substrate at a relatively low first rotational speed. The coating liquid can be quickly spread over the entire area. In addition, when applying the coating solution in the pre-coating region, the coating solution is supplied from the outer periphery (boundary) of the pre-coating region toward the substrate center point instead of concentrated dripping near the center point of the substrate. Therefore, a pre-coating film having a uniform film thickness can be efficiently formed in the pre-coating region, the impact given to the substrate is small, and there is no possibility that a drip mark will be formed on the coating film. In the second step (leveling step), spin coating is performed at a rotational speed higher than the rotational speed in the pre-coating process, and the coating liquid on the pre-coating region is dispensed. Whole substrate by centrifugal force Spread out to a uniform and desired thickness. In the second step, in order to improve leveling accuracy, it is preferable that the substrate is rotated by spinning in a substantially sealed processing chamber, and at the same time, the processing chamber is rotated at the same speed as the substrate at or near the second rotation speed. In the direction spin It can be rotated.
[0014]
In such an inscribed circle pre-coating method, a third step (pre-wetting step) of applying a solvent to a region outside the pre-coating region on the substrate is performed before the second step. Is preferred. By soaking the area outside the pre-applied area on the substrate with the solvent in this way, the resist liquid film on the substrate can be smoothly diffused and flattened in the leveling process, and high leveling can be realized.
[0015]
A preferred aspect of the third step is that the substrate is spin-rotated at a third rotation speed or a first rotation speed lower than the second rotation speed before or simultaneously with the first step. The solvent is dropped from the nozzles 2 to the outer periphery or the vicinity of the boundary of the pre-application area, and the solvent is applied almost uniformly to the substrate area outside the pre-application area. Thus, by utilizing the rotational movement of the substrate, the solvent can be applied quickly and uniformly around the pre-application region.
[0019]
The coating apparatus according to the present invention includes a rotatable holding means for holding a substrate to be processed in a horizontal posture, a substantially sealable processing container that houses the holding means, and the substrate held by the holding means. A coating liquid supply means including a first nozzle for discharging a predetermined coating liquid toward It is an area inside the inscribed circle on the substrate or a circle close thereto as a boundary. First scanning means for moving the first nozzle relative to the substrate in order to apply the coating liquid to the pre-application area, and spin-rotating the substrate integrally with the holding means First rotating means for rotating the processing vessel and second rotating means for rotating the processing vessel, While the substrate is spin-rotated at the first rotation speed by the first rotation means and the coating liquid is discharged to the first nozzle by the coating liquid supply means, the first nozzle is scanned by the scanning means. Is moved from the boundary toward the substrate center point to apply a coating solution in the pre-application region, and then the substrate is moved at a speed higher than the first rotation speed by the first rotation means. At the same time as the spin rotation at the second rotation speed, the processing container is rotated by the second rotation means at the second rotation speed or a speed close thereto, and the centrifugal force is utilized outside the pre-coating region. To spread the coating solution radially and form a coating film having a substantially uniform thickness on the substrate. .
[0022]
According to a preferred aspect of the present invention, In order to pre-wet a desired area on the substrate with the solvent prior to the leveling step, the solvent supply means for dropping the solvent to a desired position on the substrate held by the holding means is provided. Before or simultaneously with application of the coating liquid in the pre-application area, the substrate is spin-rotated at the third rotation speed or the first rotation speed lower than the second rotation speed by the first rotation means. Then, the solvent is dropped near the boundary by the solvent supply means, and the solvent is spread and applied to the area outside the pre-application area on the substrate by centrifugal force. In this case, the solvent discharge nozzle (second nozzle) can be moved integrally with the coating liquid discharge nozzle (first nozzle).
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to FIGS.
[0024]
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, development, 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.
[0025]
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.
[0026]
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.
[0027]
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.
[0028]
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.
[0029]
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.
[0030]
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.
[0031]
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.
[0032]
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.
[0033]
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).
[0034]
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.
[0035]
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.
[0036]
In the coating process unit 24, the substrate G is first sequentially carried 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).
[0037]
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).
[0038]
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.
[0039]
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).
[0040]
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.
[0041]
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).
[0042]
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) will be described with reference to FIGS.
[0043]
3 and 4, One embodiment The structure of the principal part of the resist coating unit (CT) in FIG.
[0044]
The resist coating unit (CT) includes a spin chuck 60 that rotates integrally with the substrate G held in a substantially horizontal posture, and a rotatable circuit that surrounds the spin chuck 60 and the periphery of the substrate G on the chuck. A bottom cylindrical rotary cup 62, a lid (not shown) capable of closing the upper opening of the rotary cup 62, a fixed installation type drain cup 64 surrounding the outer periphery of the rotary cup 62, and the upper surface of the substrate G ( A resist supply mechanism 66 for supplying a resist solution to the surface to be processed and a solvent supply mechanism 68 for supplying a solvent such as thinner to a predetermined region on the substrate G, which will be described later, are provided.
[0045]
The resist supply mechanism 66 includes a resist nozzle 70 for discharging and supplying a resist solution to the substrate G, a resist supply unit (not shown) that sends the resist solution to the resist nozzle 70 via a resist supply pipe 72, The resist nozzle 70 is supported by the tip of the arm 74, and has a nozzle drive unit 78 that rotates or swings the arm 74 and the nozzle 70 in a horizontal plane with a rotation shaft 76 extending in the vertical direction as a rotation center. . An elevating mechanism that moves the arm 74 and the nozzle 70 up and down by moving the rotary shaft 76 up and down may be provided in the nozzle driving unit 78. The arm 74 has such an arm length that the resist nozzle 70 can be carried in the rotary cup 62 to a position directly above the center portion of the substrate G held by the spin chuck 60.
[0046]
The solvent supply mechanism 68 includes a thinner nozzle 80 for supplying thinner to the substrate G by discharging or dropping, and a thinner supply unit (not shown) for sending thinner to the thinner nozzle 80 via a thinner supply pipe 82. Have. The thinner nozzle 80 is attached to or attached to the resist nozzle 70 and attached to the nozzle arm driving section 78 so as to move together with the resist nozzle 70.
[0047]
A pair of guide rails 84, 84 extending in the Y direction are provided outside the drain cup 64, and a pair of transfer arms 86, 86 are placed on the guide rails 84, 84 on the resist coating unit (CT) 40 and the drying unit ( VD) 42 (FIG. 1).
[0048]
The spin chuck 60 is coupled to a spin chuck drive unit 88, is rotated by a rotation of the drive unit 88 about the vertical rotation axis, and is vertically moved by a drive of the drive unit 88. A chuck suction port (not shown) connected to a negative pressure source such as a vacuum pump is provided on the upper surface of the spin chuck 60 so that the back surface of the substrate G is sucked by the chuck suction port.
[0049]
The rotating cup 62 is coupled to a common or separate cup driving unit (not shown) with the spin chuck driving unit 88, and is rotated together with the spin chuck 60 by the rotational driving of the cup driving unit, that is, at the same speed and in the same rotational direction. It is comprised so that it may rotate. The cup lid for closing the upper surface opening of the rotating cup 62 is detachably engaged with the peripheral edge of the opening of the rotating cup 62 by a handling operation by a robot hand (not shown). And rotate together. The drain cup 64 is configured to once receive the exhaust or drainage from the rotary cup 62 and send it to a predetermined exhaust or waste treatment unit (not shown).
[0050]
5 and 6 show a configuration example of the resist nozzle 70 in this embodiment. As shown in FIG. 5, the main body of the resist nozzle 70 is made of, for example, stainless steel (SUS), an introduction passage 70a for introducing a resist solution from the end (not shown) of the resist supply pipe 72, and the introduced resist. A buffer chamber 70b for once storing the liquid R, one or a plurality of nozzle discharge channels 70c extending vertically downward from the bottom surface of the buffer chamber 70b, and a fine diameter provided at the end of each nozzle discharge channel 70c. And a discharge port 70d.
[0051]
In this embodiment, as will be described later, it is not necessary to make the discharge flow of the resist solution to the substrate G as small as that of the conventional spinless method (FIG. 21). degree It is also possible to choose. In the case of a nozzle configuration in which a plurality of discharge ports 70d are arranged in one or a plurality of rows as in the illustrated example, the inscribed circle of the substrate G is made by making the discharge port arrangement direction orthogonal to the longitudinal direction of the arm 74. Or it can be made substantially parallel to the radial direction of the circumscribed circle.
[0052]
As shown in FIG. 6, in this embodiment, the terminal portion of the nozzle discharge flow path 70c is tapered (71) in a tapered section and connected to the discharge port 70d. The flow path of the discharge port 70d is opened while increasing the diameter in the vicinity of the edge, preferably while expanding the curved shape (73). According to such a configuration, the resist solution R is discharged in a stable laminar flow without generating a vortex near the discharge port 72d, and the straightness of the discharge flow is improved.
[0053]
FIG. 7 shows a processing procedure in the resist coating unit (CT). The operation of this processing procedure will be described below with reference to FIGS.
[0054]
First, the substrate G before the coating process is carried into this unit (step A1). In the coating and developing processing system of this embodiment, the substrate G before coating processing is carried in by the main transport device 54 (FIG. 1), and the spin chuck 60 is positioned higher than the upper opening of the rotary cup 62 as shown in FIG. Ascend to receive the substrate G. The cup lid is retracted to a predetermined position, and the upper opening of the rotating cup 62 is opened. When the substrate G is transferred or placed on the upper surface of the spin chuck 60, the suction force from the chuck suction port acts and the substrate G is fixed and held. Thereafter, the spin chuck 60 is lowered to a predetermined height position for a thinner pre-wet process and a pre-coating process described later.
[0055]
Next, as initialization, the nozzle driving unit 78 is operated to move the registration nozzle 70 and the thinner nozzle 80 from the home position HP (positions in FIGS. 3 and 4) to the inside of the rotary cup 62, and the setting on the substrate G is performed. As shown in FIG. 8, the nozzles 70 and 80 are aligned on the circumference of the inscribed circle K of the substrate G (step A2). Preferably, the thinner nozzle 80 may be preferentially aligned with the set position (on the circumference of the inscribed circle K). Here, the inscribed circle K defines an area on the substrate G to which the resist solution R is applied in the pre-application process, that is, an outer periphery or a boundary line of the pre-application area Ga.
[0056]
Next, in a state where both nozzles 70 and 80 are fixed at the set position, the spin chuck driving unit 88 drives the spin chuck 60 to rotate, and the substrate G is integrated with the spin chuck 60 at a predetermined low rotation speed, for example. Spin rotation is performed at 100 to 200 rpm (step A3).
[0057]
Then, as a thinner pre-wet process, the solvent supply mechanism 68 drops the thinner T from the thinner nozzle 80 to the vicinity of the circumference of the substrate inscribed circle K immediately below the substrate G that spins at a low speed (step). A4). Since the thinner T dripped onto the substrate G from the thinner nozzle 80 has low viscosity, as shown in FIG. 9, the substrate region outside the inscribed circle K (thinner pre-wet region) due to centrifugal force even at a rotational speed of about 100 rpm. Spread to Gb. In this way, when the dropping of the thinner T is continued for a predetermined time at the set position, as shown in FIG. 10, the thinner T is uniformly applied to the entire surface of the thinner pre-wet area Gb with a predetermined film thickness.
[0058]
When the thinner pre-wet process as described above is completed and the thinner nozzle 80 stops the discharge of the thinner, the resist supply mechanism 66 starts to discharge the resist solution R from the resist nozzle 70 (step A5). At this time, before starting the discharge of the resist solution R, the position of the resist nozzle 70 may be adjusted. For example, if the distance between the thinner nozzle 80 and the resist nozzle 70 is so large that it cannot be ignored, the resist nozzle 70 may be aligned directly above the substrate inscribed circle K.
[0059]
In the resist supply mechanism 66, when the discharge of the resist solution R is started as described above, the nozzle driving unit 78 swings the arm 74 in a predetermined direction (counterclockwise in FIGS. 8 to 12), and the substrate G The resist nozzle 70 is moved from the start position (position on the circumference of the substrate inscribed circle K) toward the center point of the substrate inscribed circle K (step A6).
[0060]
In this way, the resist nozzle 70 scans the circular pre-coating region Ga in the radial direction from the outside toward the center while the resist liquid R is being ejected with respect to the spin-rotating substrate G. On the coating area Ga, the resist solution R is applied annularly from the outside. As shown in FIG. 11, the coating area gradually extends to the center of the substrate inscribed circle K as the resist nozzle 70 moves (scans). . At this time, since the rotation speed of the spin rotation is low and the viscosity of the resist solution R is large, a centrifugal force that spreads the resist solution R on the substrate G toward the outer peripheral side of the substrate does not work. The spin rotation speed in this pre-coating process (step A5) may be the same as the thinner pre-wet process (step A4) in the previous process, or may be switched to a slightly different value.
[0061]
Then, when the resist nozzle 70 moves to the scanning end point position slightly past the central point of the substrate inscribed circle K, as shown in FIG. The resist solution R is supplied without any defects, and a coating film is formed with a predetermined film thickness. Here, the supply (discharge) of the resist solution R in the resist supply mechanism 66 is finished (step A7), and immediately after that, the spin rotation of the substrate G is stopped (step A8).
[0062]
When the pre-coating process is completed as described above, the nozzle driving unit 78 returns both nozzles 70 and 80 to the home position HP (step A9). At this time or stage, on the substrate G, as shown in FIG. 13, a coating film (liquid film) of the resist solution R is formed on the pre-coating region Ga around the center of the substrate with a substantially constant thickness Da. Then, a coating film (liquid film) of thinner T is formed with a substantially constant thickness Db on a region (thinner pre-wet region Gb) outside the pre-application region Ga. However, the thinner pre-wet region Gb only needs to have the entire surface wet with the thinner appropriately, and the film thickness Db of the thinner liquid may be appropriate.
[0063]
Next, a cup lid is placed over the opening of the rotating cup 62, and the processing space in the rotating cup 62 is sealed (step A10). The height position of the substrate G may be adjusted or changed by the spin chuck drive unit 88 before and after the cup closing operation.
[0064]
With the rotary cup 62 closed as described above, the resist liquid film is leveled, that is, high-speed spin rotation is performed to make the film thickness uniform (step A11). More specifically, the spin chuck drive unit 88 rotates the spin chuck 60 to spin the substrate G at a high rotational speed, for example, 1000 rpm (step A11). At the same time, the cup driver spins the rotating cup 62 together. Due to the high-speed spin rotation in the closed space, on the substrate G in the rotary cup 62, the resist solution R in the pre-application region Ga receives a strong centrifugal force in the radial direction and spreads radially outward. Here, since the thinner pre-wet area G that is the outer area is coated with the thinner, the resist solution R spreads smoothly and quickly on the area G. At this time, a considerable amount of the resist solution R is shaken off (discarded) from the outer peripheral edge of the substrate G, but the resist consumption is halved compared to the conventional general spin coating method.
[0065]
When the above-described leveling step is completed, as shown in FIG. 14, a coating film of the resist solution R spreading over the entire upper surface (surface to be processed) of the substrate G with a uniform thickness Dg is obtained. This film thickness Dg is the final resist film thickness, and the film thickness conditions include the film thickness Da of the pre-coating film on the pre-coating region Ga obtained by the pre-coating process, the rotational speed of high-speed spin rotation, and the like. Can be adjusted as
[0066]
When the resist coating process for one substrate G is completed as described above, the processed substrate G is unloaded from the resist coating unit (CT), and an unprocessed substrate G is replaced in the unit (CT). Are carried in in the same manner as described above (step A1). The processed substrate G is carried out by the transfer arms 86 and 86. More specifically, after the lid of the rotating cup 62 is opened, the transfer arms 86 and 86 move on the guide rails 84 and 84 and enter the inside of the rotating cup 62 to lift the substrate G from the spin chuck 60. (Receive) and transport to the adjacent vacuum drying unit (VD) 42 (FIG. 1).
[0067]
As described above, in this embodiment, the substrate to be processed (LCD substrate) G is spin-rotated at a low rotation speed (for example, 100 to 200 rpm) while resist is applied to the pre-coating area Ga inside the inscribed circle on the substrate G. The liquid R is applied, and then the substrate G is spin-rotated at a relatively high rotational speed (for example, 1000 rpm) so that the resist liquid film in the pre-application region Ga is spread over the entire surface of the substrate and leveled. A resist coating film having a uniform and desired film thickness is formed.
[0068]
According to this method, both the pre-coating process and the leveling process can quickly spread the resist solution R to the intended region by using the rotation of the substrate G, and the spinless method can be used in all processing steps. (Fig. 21) A much shorter tact can be achieved. Further, in the pre-coating process, the resist solution R is diffused and supplied to the pre-coating region Ga on the substrate G while scanning the fine-diameter ejection type resist nozzle 70 (since it is not a single-point concentrated dripping), the substrate G There is no fear of causing defects such as resist dropping marks.
[0069]
Further, since the fine diameter discharge conditions of the resist nozzle 70 used in the pre-coating process are not as strict as those of the conventional spinless method, the nozzle 70 and the resist supply unit can be easily designed and manufactured, and the maintenance is also simplified.
[0070]
In addition, in this embodiment, the resist solution R is applied to the pre-application region Ga including the central portion of the substrate G, while the region Gb around the pre-application region Ga is wetted with a thinner (solvent). Thus, in the leveling step, the resist liquid film on the substrate G can be smoothly diffused and flattened, and highly accurate leveling can be realized.
[0071]
In the above-described embodiment, the resist nozzle 70 and the thinner nozzle 80 are moved by the common arm 74. However, a configuration in which both the nozzles 70 and 80 can be individually moved by the dedicated arms is also possible. In that case, the thinner pre-wet process and the pre-coating process can be performed simultaneously.
[0072]
In the above embodiment, the pre-applied area Ga is defined as an area inside the inscribed circle K of the substrate G. However, it may be an inside area of a circle slightly deviated from the inscribed circle K.
[0073]
Alternatively, a method in which the pre-applied area Ga is set to an area inside the circumscribed circle L (or a circle close thereto) of the substrate G is also possible. In this method, as shown in FIG. 15, the resist nozzle 70 may be scanned at least once between a position near the center point of the substrate G and a position on the circumference of the circumscribed circle L. Since a part of the resist solution R discharged from the resist nozzle 70 is detached from the substrate G to the outer peripheral edge of the substrate G, the resist consumption is slightly increased, but it is still much more than the conventional general spin coating method. Less. Further, the thinner pre-wet process is not required, and the solvent supply system such as the thinner nozzle 80 can be omitted. In addition, since a liquid film of the resist solution R is formed on the entire surface of the substrate G with a substantially uniform film thickness at the end of the pre-coating process, the characteristic conditions in the leveling process of the next process are relaxed, and high-speed spin rotation is performed. You can also reduce the speed.
[0074]
In this circumcircle pre-coating method, as shown in FIG. 16, a resist nozzle 70 having a configuration in which discharge ports 70 are arranged in the longitudinal direction of the arm 74 may be used. In that case, the resist solution R can be applied to the entire surface of the substrate G without moving the resist nozzle 70 to the circumference of the circumscribed circle L.
[0075]
17 and 18, Another application method The structure of the principal part of the resist coating unit (CT) according to FIG. In the figure, Embodiment above The parts having the same configuration or function as those of each part in FIG.
[0076]
this Application method As shown in FIG. 18, the resist nozzle 70 is scanned in an arbitrary direction on the XY plane by the XY scanning mechanism 90. In the XY scanning mechanism 90, a pair of Y guide rails 92, 92 extending in the Y direction are disposed on both sides of the spin chuck 60 (FIG. 17), and extend in the X direction between the two Y guide rails 92, 92. The X guide rail 94 is movably bridged in the Y direction. A Y-direction drive unit 96 disposed at a predetermined position, for example, one end of the Y guide rail 92 on one side, moves the X guide rail 94 along the Y guide rails 92 and 92 via a transmission mechanism (not shown) such as an endless belt. And is driven in the Y direction. In addition, a carriage (conveyance body) 98 that can move in the X direction along the X guide rail 94 by, for example, a self-propelled type or an externally driven type is provided, and a resist nozzle 70 is attached to the carriage 98.
[0077]
In FIG. 17, the drive unit 100 includes a spin chuck drive unit 88 (FIG. 4) that drives the spin chuck 60 to rotate and lift, and also includes a cup drive unit that drives the rotary cup 62 to rotate. The bottom portion of the rotating cup 62 is operatively connected to a cup driving unit included in the driving unit 100 via a cylindrical support member 102.
[0078]
A cup lid 106 that can be moved up and down by the robot arm 104 is disposed above the rotating cup 62. During the pre-application process, the lid body 106 is retracted above the XY scanning mechanism 90. During the leveling process, the lid 106 comes down and the rotary cup 62 is closed. Although not shown, the lid 106 and the upper surface of the rotary cup 62 are configured to engage with each other. In the leveling process, the spin chuck 60 and the rotary cup 62 are rotated together by the drive of the drive unit 100, so that the resist solution R is spread on the substrate G by centrifugal force and scattered outside the substrate G. Is received by the rotating cup 62. A ring-shaped sealing member 108 for sealing the bottom surface of the rotary cup 62 is attached to the lower surface of the spin chuck 60.
[0079]
The resist solution R collected in the rotating cup 62 is guided to the drain cup 64 through the drain port 110 formed at the outer peripheral edge of the bottom of the cup 62, and is discharged from the drain port 112 at the bottom of the drain cup 64 ( (Not shown). In addition, in order to prevent air from flowing out from the drain port 112 during the spin rotation and causing the inside of the rotary cup 62 to become negative pressure, an appropriate air supply port (not shown) is provided on the upper part of the rotary cup 62 or the lid body 106. ) May be provided. Air flowing into the drain cup 64 from the rotary cup 62 side is discharged to an exhaust system (not shown) from an exhaust port 114 formed on the outer peripheral surface of the drain cup 64.
[0080]
this Application method Then, after performing the pre-coating step of applying the resist solution R on the pre-coating pattern set so as to cover the entire area of the upper surface (surface to be processed) of the substrate G as a pre-coating region, A leveling process similar to that in the first embodiment is performed. In the pre-coating process, the resist nozzle 70 moves in the XY plane along a pre-coating pattern (path) set in advance while discharging the resist solution R on the stationary substrate G. If necessary, it is also possible to move (rotate) the substrate G in synchronization with the movement of the resist nozzle 70.
[0081]
In FIG. Application method The example of the suitable front application | coating pattern in is shown. The pattern shown in FIG. 19A has a quadrangular spiral shape that matches the shape of the substrate G, and normally it is preferably converged from the outside (substrate outer peripheral portion) to the inside (substrate central portion) as shown in the figure. Since this pattern has good radial symmetry, it is preferable for leveling (high-speed spin) in the next step.
[0082]
The oblique zigzag pattern as shown in FIG. 19B and the right zigzag pattern as shown in FIG. 19C efficiently form the pre-coating film with a substantially uniform distribution or distribution over the entire substrate. Suitable for
[0083]
As shown in FIG. 20, when the resist nozzle 70 has a relatively large angle, particularly when there are many places where the direction is changed to a right angle, as in the pre-coating pattern of FIG. By setting the direction to an oblique angle (for example, 45 °) with respect to the scanning or moving direction, the variation in the width of the resist coating line RJ obtained on the substrate G during scanning can be reduced.
[0084]
this Application method Then, in the pre-coating process, the resist nozzle 70 can be scanned over the substrate G without being moved out of the substrate G, and the resist solution can be applied to almost the entire area of the substrate G. Part of it is not wasted. As a result, the consumption amount of the resist solution is much smaller than that of the conventional general spin coating method. Further, in the pre-coating process, the resist solution R has only to be distributed to a certain extent on the substrate G, and it is not necessary to uniformly apply to the entire surface of the substrate. Therefore, the entire coating processing time combined with the leveling process is conventional. The tact is shorter than the spinless method. Moreover, since a thinner pre-wet is unnecessary, the solvent supply system can be omitted. However, it is also possible to apply a resist solution around the center of the substrate in the pre-coating process and pre-wet the periphery with a thinner. In the leveling process, The above circumscribed circle pre-coating method The rotational speed of the high-speed spin rotation can be lowered to the same level as in FIGS.
[0085]
In addition, when using the XY scanning mechanism 90 that moves the resist nozzle 70 in the XY plane as described above, the pre-coating process is performed with the substrate G stationary, but the substrate G side may be moved, For example, a configuration in which the substrate G is moved in the Y direction and the resist nozzle 70 is moved in the X direction is also possible.
[0086]
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.
[0087]
【The invention's effect】
As described above, according to the present invention, it is possible to simultaneously improve the coating liquid consumption efficiency and shorten the processing time in the coating process. Further, even if the substrate to be processed is enlarged, a high-quality coating film having a uniform in-plane film thickness can be efficiently formed on the substrate. Furthermore, it is possible to ease the design and maintenance by relaxing the fine diameter discharge conditions of the nozzle.
[Brief description of the drawings]
FIG. 1 is a plan view showing a configuration of a coating and developing treatment 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] Embodiment It is a top view which shows the structure of the principal part of the resist application unit by.
[Fig. 4] Embodiment It is a side view which shows the structure of the principal part of this resist application unit.
FIG. 5 is a longitudinal sectional view showing a configuration example of a resist nozzle in the embodiment.
FIG. 6 is a partially enlarged cross-sectional view showing an enlarged main part of a resist nozzle in the embodiment.
FIG. 7 is a flowchart showing a processing procedure in the resist coating unit of the embodiment.
FIG. 8 is a plan view schematically showing one stage of action in the resist coating unit of the embodiment.
FIG. 9 is a plan view schematically showing one stage of action in the resist coating unit of the embodiment.
FIG. 10 is a plan view schematically showing one stage of action in the resist coating unit of the embodiment.
FIG. 11 is a plan view schematically showing one stage of action in the resist coating unit of the embodiment.
FIG. 12 is a plan view schematically showing one stage of action in the resist coating unit of the embodiment.
FIG. 13 Embodiment It is a side view which shows the coating film formed on a board | substrate by a pre-application process in FIG.
FIG. 14 Embodiment FIG. 2 is a side view showing a coating film formed on a substrate by a leveling process.
FIG. 15 Action of circumscribed circle pre-coating method FIG.
FIG. 16 Circumscribed circle pre-coating method It is a top view which shows the modification of the resist nozzle in
FIG. 17 Another application method It is a top view which shows the structure of the principal part of the resist application unit by.
FIG. 18 Application method It is a perspective view which shows the structure of the XY scanning mechanism provided in the resist application unit.
FIG. 19 Application method It is a top view which shows typically an example of the front application | coating pattern.
FIG. 20 Application method It is a top view which shows typically the discharge port arrangement | positioning direction of a suitable resist nozzle.
FIG. 21 is a perspective view schematically showing a resist coating process by a conventional spinless method.

Claims (7)

While rotating the substrate to be processed at the first rotation speed, the inscribed circle on the substrate or a circle close thereto is used as a boundary to the pre-coating region, which is the inner region, from the boundary toward the substrate center point. A first step of supplying and applying a predetermined coating liquid;
After the first step, the substrate is spin-rotated at a second rotation speed that is higher than the first rotation speed, and a coating solution is applied from the inside to the outside of the pre-coating area using a centrifugal force. And a second step of forming a coating film having a substantially uniform film thickness on the substrate . Wherein prior to the second step, the method of coating according to claim 1, characterized in that than the front置塗fabric region on the substrate comprises a third step of applying a solvent to the outer area. In the third step, the substrate is spin-rotated at a third rotation speed lower than the second rotation speed or the first rotation speed before or simultaneously with the first process, A solvent is dropped from the nozzle of 2 near the boundary, and the solvent is radially spread by a centrifugal force on a region outside the pre-coating region on the substrate and applied almost uniformly. Item 3. The coating method according to Item 2 . The second step, simultaneously with the spinning of the substrate in the processing chamber substantially sealed state, that is spinning in the same rotational direction as the substrate of the processing chamber at the second rotation speed or close to the speed The coating method according to any one of claims 1 to 3 . A rotatable holding means for holding the substrate to be processed in a horizontal posture;
A substantially hermetically sealable processing container containing the holding means;
A coating liquid supply means including a first nozzle for discharging a predetermined coating liquid toward the substrate held by the holding means;
In order to move the first nozzle relative to the substrate in order to apply the coating liquid to a pre-coating region, which is an inner region of the inscribed circle on the substrate or a circle close thereto, as a boundary. Scanning means,
First rotating means for spinning the substrate integrally with the holding means;
The processing container have a second rotation means for spinning,
While the substrate is spin-rotated at the first rotation speed by the first rotation means and the coating liquid is discharged to the first nozzle by the coating liquid supply means, the first nozzle is scanned by the scanning means. Is moved from the boundary toward the substrate center point to apply a coating solution in the pre-application region, and then the substrate is moved at a speed higher than the first rotation speed by the first rotation means. At the same time as the spin rotation at the second rotation speed, the processing container is rotated by the second rotation means at the second rotation speed or a speed close thereto, and the centrifugal force is utilized outside the pre-coating region. Then, the coating liquid is spread radially to form a coating film having a substantially uniform film thickness on the substrate . Have a solvent supply means for dropping the solvent in a desired position on the substrate held by the holding means,
Before or simultaneously with applying the coating liquid in the pre-application area, the first rotating means causes the substrate to move at a third rotational speed lower than the second rotational speed or at the first rotational speed. while spinning, dropping a solvent in the vicinity of the boundary by the solvent supply means, for applying spread by a centrifugal force the solvent to the outside of the area than the front置塗fabric region on the substrate, according to claim 5 Coating device. The coating apparatus according to claim 6 , wherein the solvent supply unit includes a second nozzle movable integrally with the first nozzle for discharging the solvent.

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