JP4809699B2 - Coating method and coating apparatus - Google Patents

Description

  The present invention relates to a coating method and a coating apparatus for forming a coating film of a processing liquid on a substrate to be processed using a long nozzle.

  In a photolithography process in the manufacturing process of flat panel displays (FPD) such as LCD, a long resist nozzle having a slit-like discharge port is scanned to apply a resist solution onto a substrate to be processed (glass substrate or the like). A spinless coating method is often used.

As one form of such a spinless coating method, for example, as disclosed in Patent Document 1, a stage for supporting a substrate is configured to be a floating type, and the substrate is transported in a horizontal direction while floating in the air on the stage. The resist solution is applied from one end to the other end of the substrate by discharging the resist solution in a strip shape toward the substrate passing directly below the long resist nozzle installed above the stage at a predetermined application position. The levitation transfer method is known. Such a levitation transport method is a conventional general nozzle movement method, that is, a substrate is fixed on a suction-type stage, and a resist solution is ejected in a belt shape while moving a long resist nozzle in the horizontal direction above the substrate. Compared with the method in which resist solution is applied from one end to the other on the substrate, application scanning can be performed with the long resist nozzle fixed, which is advantageous for increasing the size of the substrate (that is, increasing the length of the resist nozzle). It is said that.
JP 2005-244155 A

  In any of the above-described floating conveyance method and nozzle movement method, there is room for improvement in the control of the film thickness of the resist coating film formed on the substrate by one coating scan, and in-plane uniformity is particularly a problem. ing. Specifically, there is a problem that the in-plane uniformity in the vicinity of the start portion and the end portion of the application scan is low.

  The film thickness of the resist coating film in this type of spinless coating method is determined by two parameters, that is, the flow rate or pressure at which the resist nozzle discharges the resist solution, and the relative speed (scanning speed) of the resist nozzle with respect to the substrate. For this reason, conventionally, at least one of a discharge pressure control waveform and a scan speed control waveform for controlling the temporal characteristics of the discharge pressure and the scanning speed of the resist nozzle each time during the application scan is applied each time. Discharge pressure control waveform and scanning speed control waveform that can obtain coating film with the most excellent film thickness uniformity by performing coating application for test according to actual application processing in a variable or modified manner. The determined discharge pressure control waveform and scanning speed control waveform were used as the reference for discharge pressure control and scanning speed control in the actual coating process, respectively.

  However, the method of obtaining the optimum conditions for the coating process by trial and error by repeating a number of test coating processes in this way not only imposes considerable skill and a great amount of work time on the field operator, but also for testing. Since a large number of substrates are used for the coating process, and before and after processes (cleaning process, drying process, baking process, etc.) are required, there are problems of system complexity and high cost in implementation.

  The present invention has been made in view of the above-described problems of the prior art, and is an optimal control waveform and timing for improving the coating film thickness uniformity with respect to the nozzle discharge pressure and the scanning speed in the spinless coating method. It is an object of the present invention to provide a coating method and a coating apparatus in which conditions are easily obtained.

In order to achieve the above-described object, the coating method of the present invention is configured such that a substrate to be processed and a discharge port of a long nozzle are opposed to each other substantially horizontally with a small gap, and a reference discharge pressure control is performed on the substrate. A normal coating scan is performed in which the nozzle is moved in a relatively horizontal direction according to a reference scanning speed control waveform while discharging the processing liquid from the nozzle according to the waveform, and the coating film of the processing liquid is formed on the substrate. A coating method to be formed, wherein a treatment liquid is ejected in advance between the nozzle and the stage in accordance with a provisional ejection pressure control waveform preset in the nozzle on a stage for supporting the substrate. A simulated application scanning process in which relative movement scanning is performed according to a set temporary scanning speed control waveform, and a discharge pressure by measuring the discharge pressure of the nozzle during the simulated application scanning process. A discharge pressure measurement step of obtaining a measurement waveform, and scan speed measurement step of obtaining the scanning speed measurement waveform the simulated coating speed of the scanning measurement to during the scanning process, the discharge pressure measurement waveform and the scanning speed measurement waveform a normalization step of normalizing the waveform comparison step of comparing each of the rising part and falling part on the same time axis of the normalized discharge pressure measured waveform and the normalized scanning speed measurement waveform When the difference in waveform shape between the discharge pressure measurement waveform and the scanning speed measurement waveform is larger than a predetermined allowable value as a result of the comparison performed in the waveform comparison step, the temporary discharge pressure control waveform And correcting the waveform shape of at least one of the temporary scanning speed control waveforms, the simulated application scanning step, the discharge pressure measuring step, the normalizing step, and the waveform comparison process. When the waveform shape difference between the discharge pressure measurement waveform and the scanning speed measurement waveform is smaller than a predetermined allowable value as a result of the comparison performed in the correction step and the waveform comparison step again, A control waveform setting step for setting the temporary discharge pressure control waveform and the temporary scanning speed control waveform as the reference discharge pressure control waveform and the reference scanning speed control waveform, respectively .

The coating apparatus of the present invention includes a stage for supporting a substrate to be processed substantially horizontally, a long nozzle for discharging a processing liquid from above the stage toward the stage, and the processing applied to the nozzle. A processing liquid supply mechanism for pumping liquid, a scanning unit for moving the nozzle in a horizontal direction relative to the stage, and a nozzle in the vertical direction relative to the substrate. A lifting / lowering section for measuring the discharge pressure of the nozzle in the middle of the processing liquid passage from the processing liquid supply mechanism to the nozzle outlet, and the scanning speed of the relative movement of the nozzle with respect to the stage. A scanning speed measurement unit to measure, a discharge pressure measurement value and a scanning speed measurement value from the pressure measurement unit and the scanning speed measurement unit are received, and the processing liquid supply mechanism, the scanning unit, and the front And a control unit that controls the elevating unit. Under the control of the control unit, the processing liquid is discharged by the processing liquid supply mechanism according to a temporary discharge pressure control waveform preset on the nozzle on the stage. The scanning unit performs scanning of relative movement according to a preset temporary scanning speed control waveform between the nozzle and the stage, and measures the discharge pressure of the nozzle through the pressure measurement unit. A measurement waveform is acquired, and a scanning speed measurement waveform is acquired by measuring a scanning speed of the relative movement through the scanning speed measurement unit. The control unit normalizes the discharge pressure measurement waveform and the scanning speed measurement waveform. When the rising part and the falling part of the normalized discharge pressure measurement waveform and the normalized scanning speed measurement waveform are the same, If the difference in waveform shape between the discharge pressure measurement waveform and the scanning speed measurement waveform is larger than a predetermined allowable value in the waveform comparison, the temporary discharge pressure control waveform and the temporary The processing liquid supply mechanism is corrected under the control of the control unit using the provisional discharge pressure control waveform and the provisional scanning speed control waveform after correction. The processing liquid is discharged by the scanning unit and the scanning of the relative movement by the scanning unit is performed again, and the discharge pressure measurement waveform and the scanning speed measurement waveform are obtained again through the pressure measuring unit and the scanning speed measuring unit, and the control is performed. In the section, the discharge pressure measurement waveform and the scanning speed measurement waveform are respectively normalized again, and the waveforms are compared again on the same time axis. When the difference in waveform shape between the discharge pressure measurement waveform and the scan speed measurement waveform is smaller than a predetermined allowable value, the temporary discharge pressure control waveform and the temporary scan speed control waveform are respectively used as reference discharges. A pressure control waveform and a reference scanning speed control waveform are set, and under the control of the control unit, the substrate and the discharge port of the nozzle are made substantially horizontal with a small gap on the stage by the elevating unit. The nozzle is moved in a relatively horizontal direction according to the reference scanning speed control waveform by the scanning unit while the processing liquid is discharged from the nozzle according to the reference discharge pressure control waveform by the processing liquid supply mechanism. It is moved to form a coating film of the treatment liquid on the substrate.

  In the present invention, the reference discharge pressure control waveform and the reference scanning speed control waveform used for regular application processing are gradually narrowed down and set through simulated application scanning without actually applying the processing liquid on the substrate. Human burden, system environment, and cost for work can be greatly or significantly reduced, simplified, and reduced.

In particular, in the present invention, the relative relationship between the discharge pressure and the scanning speed is simply and accurately evaluated by normalizing the discharge pressure measurement waveform and the scanning speed measurement waveform and comparing them on the same time axis. be able to. Further, when the difference (error) in the waveform shape between the normalized discharge pressure measurement waveform and the normalized scanning speed measurement waveform exceeds a predetermined allowable value, the difference (error) is reduced. After tuning (correcting) the relative waveform shape (rising slope, falling slope, etc.) of both waveforms in the direction, simulated application scanning process, discharge pressure measurement process, normalization process and waveform comparison process By performing again, the temporary ejection pressure control waveform and the temporary scanning speed control waveform approach an ideal relationship. Thus, when the difference (error) between the two waveforms is smaller than the allowable value, the temporary discharge pressure control waveform and the temporary scanning speed control waveform at that time are used as the reference discharge pressure control waveform and the reference scanning speed control waveform as they are. Can be set or used.

According to a preferred aspect of the present invention, when there is a certain time delay between the discharge pressure measurement waveform and the discharge flow rate waveform of the nozzle, the time difference between the discharge pressure measurement waveform and the scanning speed measurement waveform is Correction is applied to at least one timing of the temporary ejection pressure control waveform and the temporary scanning speed control waveform so as to be substantially equal to the time delay.

  In the present invention, it is preferable to provide a processing liquid recovery unit for recovering the processing liquid discharged from the nozzle during the simulation coating scan without dropping it on the stage.

  According to the coating method and the coating apparatus of the present invention, the optimum conditions of the control waveform and the timing for improving the coating film thickness uniformity with respect to the nozzle discharge pressure and the scanning speed in the spinless coating method by the configuration and operation as described above. It can be easily obtained.

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

  FIG. 1 shows a coating and developing treatment system as a configuration example to which the coating method and coating apparatus of the present invention can be applied. 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.

  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.

  A cassette station (C / S) 10 installed at one end of the system includes 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 side on the cassette stage 16. And a transport path 17 provided in parallel with the arrangement direction of the cassette C, and a transport mechanism 20 that is movable on the transport path 17 and that allows the substrate C to be taken in and out of the cassette C on the stage 16. 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 transported on the process station (P / S) 12 side described later. And the substrate G can be transferred.

  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.

  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.

  The coating process unit 24 includes a spinless resist coating unit (CT) 40, a vacuum drying unit (VD) 42, an upper and lower two-stage adhesion / cooling unit (AD / COL) 46, and an upper and lower two-stage heating / cooling. A unit (HP / COL) 48 and a heating unit (HP) 50 are included.

  The development process unit 26 includes three development units (DEV) 52, two upper and lower two-stage heating / cooling units (HP / COL) 53, and a heating unit (HP) 55.

  Conveying paths 36, 51, 58 are provided in the longitudinal direction at the center of each process unit 22, 24, 26, and the conveying devices 38, 54, 60 move along the conveying paths 36, 51, 58, respectively. Each unit in the process unit is accessed to carry in / out or carry the substrate G. In this system, in each process part 22, 24, 26, a liquid processing system unit (SCR, CT, DEV, etc.) is disposed on one side of the transport paths 36, 51, 58, and heat treatment is performed on the other side. System units (HP, COL, etc.) are arranged.

  The interface unit (I / F) 14 installed at the other end of the system is provided with an extension (substrate transfer unit) 56 and a buffer stage 57 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. The transport mechanism 59 is movable on the transport path 19 extending in the Y direction, and is used to load and unload the substrate G with respect to the buffer stage 57, and to extend from the extension (substrate transfer unit) 56 and the adjacent exposure device. The substrate G is transferred.

  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 cassette stage 16, and the cleaning process unit 22 of the process station (P / S) 12. It is transferred to the conveying device 38 (step S1).

  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 first ultraviolet irradiation unit (UV), and then subjected to the next cooling unit ( In COL), the temperature is cooled to a predetermined temperature (step S2). This UV cleaning mainly removes organic substances on the substrate surface.

  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 transfer device 38 via the substrate transfer unit 23.

  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).

  Thereafter, the substrate G is coated with a resist solution by a spinless method in a resist coating unit (CT) 40, and then subjected to a drying process by reduced pressure in a reduced pressure drying unit (VD) 42 (step S8).

  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.

  After the coating process, the substrate G is transported to the interface unit (I / F) 14 by the transport device 54 of the coating process unit 24 and the 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 56 (step S11).

  In the development process unit 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) 53, 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) 55 can also be used for this post-baking.

  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).

  In this coating and developing system, the present invention can be applied to, for example, the resist coating unit (CT) 40 of the coating process unit 24. An embodiment in which the present invention is applied to a resist coating unit (CT) 40 will be described below with reference to FIGS.

  FIG. 3 shows the overall configuration of the resist coating unit (CT) 40 and the vacuum drying unit (VD) 42 in this embodiment.

As shown in FIG. 3, a resist coating unit (CT) 40 and a vacuum drying unit (VD) 42 are arranged in a horizontal row on the support base or support frame 70 in the X direction. A new substrate G to be subjected to the coating process is carried into the resist coating unit (CT) 40 as indicated by an arrow F _A by the transfer device 54 (FIG. 1) on the transfer path 51 side. Substrate G after completion of the coating process in the resist coating unit (CT) 40 is a transfer arm 74 which is movable in the X direction is guided by the guide rails 72 on the support table 70, a vacuum drying unit as indicated by the arrow F _B (VD) 42. Substrate G having been subjected to the drying treatment in a vacuum drying unit (VD) 42 is drawn off as shown by the arrow F _C by the transfer device 54 of the transport path 51 side (FIG. 1).

  The resist coating unit (CT) 40 includes a stage 76 that extends long in the X direction, and a long shape disposed above the stage 76 while carrying the substrate G in a flat flow on the stage 76 in the same direction. A resist solution is supplied onto the substrate G from the resist nozzle 78, and a resist coating film having a constant film thickness is formed on the upper surface (surface to be processed) of the substrate by a spinless method. The configuration and operation of each part in the unit (CT) 40 will be described in detail later.

  The vacuum drying unit (VD) 42 includes a tray or shallow container type lower chamber 80 having an open upper surface, and a lid-shaped upper chamber configured to be tightly fitted or fitted to the upper surface of the lower chamber 80. (Not shown). The lower chamber 80 is substantially rectangular, and a stage 82 for placing and supporting the substrate G horizontally is disposed at the center, and exhaust ports 83 are provided at the four corners of the bottom surface. Each exhaust port 83 communicates with a vacuum pump (not shown) through an exhaust pipe (not shown). With the lower chamber 80 covered with the upper chamber, the sealed processing space in both chambers can be depressurized to a predetermined degree of vacuum by the vacuum pump.

  4 and 5 show a more detailed overall configuration in the resist coating unit (CT) 40 in one embodiment of the present invention.

  In the resist coating unit (CT) 40 of this embodiment, the stage 76 does not function as a mounting table for fixing and holding the substrate G as in the prior art, but a substrate for floating the substrate G in the air by the force of air pressure. It functions as a levee Then, the linear movement type substrate transport portions 84 arranged on both sides of the stage 76 hold both side edges of the substrate G floating on the stage 76 in a detachable manner, and the stage longitudinal direction (X direction) The substrate G is transferred to the substrate.

Specifically, the stage 76 is divided into _five regions M ₁ , M ₂ , M ₃ , M ₄ , and M ₅ in the longitudinal direction (X direction) (FIG. 5). The leftmost area M ₁ is a carry-in area, and a new substrate G to be subjected to the coating process is carried into a predetermined position in this area M ₁ . In this carry-in area M ₁ , the substrate G is received from the transfer arm of the transfer device 54 (FIG. 1) and loaded onto the stage 76 so as to move up and down between the original position below the stage and the forward movement position above the stage. A plurality of possible lift pins 86 are provided at predetermined intervals. These lift pins 86 are driven up and down by, for example, a carry-in lift pin lift unit 85 (FIG. 14) using an air cylinder (not shown) as a drive source.

The loading area M ₁ is also the area substrate transfer of a floating starts, high-pressure or positive pressure to the stage upper surface of the region to float in flying height or flying height H _a for carrying the substrate G A number of jet outlets 88 for jetting compressed air are provided at a constant density. Here, the flying height H _a of the substrate G in the carrying region M ₁ does not require a particularly high accuracy, for example if kept in the range of 250～350Myuemu. Further, it is preferable that the size of the carry-in area M ₁ exceeds the size of the substrate G in the transport direction (X direction). Further, an alignment unit (not shown) for aligning the substrate G on the stage 76 may be provided in the carry-in area M ₁ .

A region M ₃ set at the center of the stage 76 is a resist solution supply region or a coating region, and the substrate G is supplied with the resist solution R from the upper resist nozzle 78 when passing through the coating region M ₃ . The substrate flying height _Hb in the coating region M ₃ defines a coating gap S (for example, 240 μm) between the lower end (discharge port) of the nozzle 78 and the upper surface of the substrate (surface to be processed). The coating gap S is an important parameter that affects the film thickness of the resist coating film and the resist consumption, and must be kept constant with high accuracy. From this, on the upper surface of the stage of the application region M ₃ , for example, a jet that ejects high-pressure or positive-pressure compressed air to float the substrate G with a desired flying height H _b in an arrangement or distribution pattern as shown in FIG. An outlet 88 and a suction port 90 for sucking air with a negative pressure are mixed and provided. Then, a vertical upward force due to compressed air is applied from the jet outlet 88 to a portion passing through the coating region M ₃ of the substrate G, and at the same time, a vertical downward force due to a negative pressure suction force is applied from the suction port 90. In addition, the flying height _Hb for application is maintained in the vicinity of a set value H _S (for example, 50 μm) by controlling the balance of the opposing forces. The size of the coating region M ₃ in the transport direction (X direction) only needs to be large enough to stably form the narrow coating gap S as described above immediately below the resist nozzle 78 and is usually smaller than the size of the substrate G. For example, about 1/3 to 1/4 may be sufficient.

As shown in FIG. 6, in the application region M ₃ , the jet ports 88 and the suction ports 90 are alternately arranged on a straight line C that forms an angle inclined with respect to the substrate transport direction (X direction). An appropriate offset α is provided for the pitch on the straight line C between the columns. According to such an arrangement pattern, not only can the mixing density of the nozzles 88 and the suction ports 90 be made uniform, the substrate levitation force on the stage can be made uniform, but also when the substrate G moves in the transport direction (X direction). It is also possible to make the ratio of the time facing the 88 and the suction port 90 uniform in each part of the substrate, whereby the coating film formed on the substrate G is traced or transferred by the ejection port 88 or the suction port 90. Can be prevented. At the entrance of the coating region M ₃ , the jet outlets 88 arranged in the same direction (on the straight line J) so that the tip of the substrate G stably receives a uniform levitation force in the direction (Y direction) perpendicular to the transport direction, and It is preferable to increase the density of the suction port 90. Also in the coating region M ₃ , it is preferable to arrange only the ejection port 88 at both side edges (on the straight line K) of the stage 76 in order to prevent the both side edges of the substrate G from dripping.

5 again, the middle region M _2, which is set between the loading area M ₁ and the application area M ₃ are, coating the flying height of the substrate G during transport from the flying height H _a of the loading area M ₁ it is a transition region for changing or transition to flying height H _b in the area M _3. Even in the transition region M ₂ , the jet port 88 and the suction port 90 can be mixed and arranged on the upper surface of the stage 76. In that case, the density of the suction port 90 gradually increases along the conveying direction, whereby it as the flying height of the substrate G during transport moves in H _b from progressively H _a. Alternatively, in this transition region M ₂ , a configuration in which only the ejection port 88 is provided without including the suction port 90 is also possible.

A region M ₄ adjacent to the downstream side of the coating region M ₃ is a transition region for changing the flying height of the substrate G from the flying height H _b for coating to the flying height H _c (for example, 250 to 350 μm) during transportation. It is. Even in the transition region M ₄ , the ejection port 88 and the suction port 90 may be mixed on the upper surface of the stage 76, and in this case, the density of the suction port 90 should be gradually reduced along the transport direction. . Alternatively, a configuration in which only the ejection port 88 is provided without including the suction port 90 is also possible. In addition, as shown in FIG. 6, in the transition region M ₄ as well as the coating region M ₃ , the suction port 90 (and the spray nozzle 90) is used to prevent the transfer mark from being applied to the resist coating film formed on the substrate G. It is preferable that the outlet 88) is disposed on a straight line E that forms a certain inclined angle with respect to the substrate transport direction (X direction), and an appropriate offset β is provided in the arrangement pitch between adjacent rows.

A region M ₅ at the downstream end (right end) of the stage 76 is a carry-out region. The resist coating unit (CT) substrate G having received a coating process with 40, the transport arm 74 from a predetermined position or unloading position of the unloading area M ₅ vacuum drying unit on the downstream side next (FIG. 3) (VD) 42 ( 3). In the carry-out area M ₅ , a number of jet outlets 88 for floating the substrate G with a flying height H _c for carrying out are provided on the upper surface of the stage at a constant density, and the substrate G is unloaded from the stage 76. Thus, a plurality of lift pins 92 that can be moved up and down between the original position below the stage and the forward movement position above the stage are provided at predetermined intervals for delivery to the transfer arm 74 (FIG. 3). These lift pins 92 are driven up and down by, for example, a lift pin lift unit 91 (FIG. 13) for carrying out using an air cylinder (not shown) as a drive source.

  The resist nozzle 78 has a length that can cover the substrate G on the stage 76 from one end to the other end, and has a slit-like discharge port 78a at the lower end of a long nozzle body that extends in the horizontal direction (Y direction) perpendicular to the transport direction. And is attached to a nozzle-shaped or inverted U-shaped nozzle support 130 so as to be movable up and down, and is connected to a resist solution supply pipe 94 (FIG. 4) from a resist solution supply mechanism 95 (FIGS. 12 and 14). .

  As shown in FIGS. 4, 7, and 8, the substrate transport unit 84 includes a pair of guide rails 96 arranged in parallel on the left and right sides of the stage 76, and an axial direction (X direction) on each guide rail 96. A slider 98 movably attached to each other, a transport drive unit 100 for moving the slider 98 linearly on each guide rail 96, and right and left side edges of the substrate G extending from each slider 98 toward the center of the stage 76. And a holding portion 102 that holds the detachable holder.

  Here, the conveyance drive unit 100 is configured by a linear drive mechanism such as a linear motor. The holding unit 102 supports the suction pad 104 coupled to the lower surfaces of the left and right side edges of the substrate G by a vacuum suction force, and supports the suction pad 104 at the distal end, with the proximal end on the slider 98 side serving as a fulcrum. And a plate spring type pad support portion 106 that can be elastically deformed so that the height position of each can be changed. The suction pads 104 are arranged in a line at a constant pitch, and the pad support part 106 supports each suction pad 104 independently. As a result, the individual suction pads 104 and the pad support portions 106 can stably hold the substrate G at independent height positions (even at different height positions).

  As shown in FIGS. 7 and 8, the pad support portion 106 in this embodiment is attached to a plate-like pad elevating member 108 attached to the inner surface of the slider 98 so as to be elevable. A pad actuator 109 (FIG. 14) made of, for example, an air cylinder mounted on the slider 98 moves the pad lifting / lowering member 108 to an original position (retracted position) lower than the flying height position of the substrate G and the flying height of the substrate G. It is configured to move up and down between the forward movement position (coupling position) corresponding to the position.

  As shown in FIG. 9, each suction pad 104 is provided with a plurality of suction ports 112 on the upper surface of a rectangular parallelepiped pad body 110 made of, for example, synthetic rubber. These suction ports 112 are slit-like long holes, but may be round or rectangular small holes. For example, a belt-like vacuum tube 114 made of synthetic rubber is connected to the suction pad 104. The pipe lines 116 of these vacuum pipes 114 respectively communicate with the vacuum source of the pad suction control unit 115 (FIG. 14).

  As shown in FIG. 4, the holding unit 102 preferably has a separation type or completely independent type in which the vacuum suction pads 104 and the pad support units 106 on one side are separated for each set. However, as shown in FIG. 10, a single plate spring provided with a notch 118 is used to form a pad support portion 120 for one row on one side, and a vacuum suction pad 104 is placed on one row on the pad support portion 120. Configuration is also possible.

  In order to measure the moving speed of the slider 98, the substrate transport unit 84 includes a speed sensor 115 made of, for example, a linear encoder, as shown in FIG. The speed sensor 115 of this configuration example includes a slit-type scale 117 attached to the slider 98 and extending in the transport direction (X direction), a light projecting unit 119A and a light receiving unit 119B that are opposed to each other with the scale 117 interposed therebetween, and a light receiving unit. A signal processing unit 121 that obtains the moving speed of the slider 98 by signal processing (calculation) based on the output signal of 119B. The output signal (speed measurement value) of the signal processing unit 121 is sent to a local controller (not shown) in the substrate transport unit 84 for speed feedback control, and a main controller for setting a scanning speed control waveform to be described later. 200 (FIG. 14).

As described above, the large number of jets 88 formed on the upper surface of the stage 76, the compressed air supply mechanism 122 (FIG. 11) for supplying the compressed air for generating the levitation force to them, and the coating region M _{3 of the} stage 76 The substrate G is carried in the carry-in area M ₁ and the carry-out area M ₅ by a large number of suction ports 90 formed in the inside of the jet outlet 88 and a vacuum supply mechanism 124 (FIG. 11) for supplying vacuum pressure thereto. out and floated in flying height suitable for high-speed transport, stage substrate floating unit 145 for float in setting flying height H _S suitable for stable and accurate resist coating scanned coating area M ₃ in the substrate G (FIG. 14) is configured Has been.

FIG. 11 shows the configuration of the nozzle lifting mechanism 75, the compressed air supply mechanism 122, and the vacuum supply mechanism 124. The nozzle raising / lowering mechanism 75 is attached to the gate-shaped frame 130 and the portal frame 130 laid so as to straddle the coating region M _{3 in} the horizontal direction (Y direction) orthogonal to the transport direction (X direction). It has a pair of left and right vertical motion mechanisms 132L and 132R, and a nozzle support 134 of a moving body (lifting body) straddling between these vertical motion mechanisms 132L and 132R. The drive units of the vertical motion mechanisms 132L and 132R include electric motors 138L and 138R made of, for example, pulse motors, ball screws 140L and 140R, and guide members 142L and 142R. The rotational force of the pulse motors 138L and 138R is converted into a linear motion in the vertical direction by the ball screw mechanisms (140L and 142L) and (140R and 142R), and the registration nozzle 78 moves up and down integrally with the nozzle support 134 of the lifting body. Moving. The amount of elevation movement and the height position of the left and right sides of the registration nozzle 78 can be arbitrarily controlled by the rotation amounts and rotation stop positions of the pulse motors 138L and 138R. The nozzle support 134 is made of, for example, a prismatic rigid body, and a resist nozzle 78 is detachably attached to the lower surface or side surface of the nozzle support 134 via a flange, a bolt, or the like.

  The compressed air supply mechanism 122 includes a positive pressure manifold 144 connected to a jet outlet 88 for each of a plurality of areas divided on the upper surface of the stage 76, and compressed air from a compressed air supply source 146 of factory force, for example, to the positive pressure manifold 144. Compressed air supply pipe 148 and a regulator 150 provided in the middle of the compressed air supply pipe 148. The vacuum supply mechanism 124 includes a negative pressure manifold 152 connected to the suction port 90 for each of a plurality of areas divided on the upper surface of the stage 76, and a vacuum that feeds, for example, vacuum from a vacuum source 154 of factory power into the negative pressure manifold 152. A pipe 156 and a throttle valve 158 provided in the middle of the vacuum pipe 156 are provided.

  FIG. 12 shows the configuration of the resist solution supply mechanism 170. The resist solution supply mechanism 170 pre-fills the resist pump 176 with the resist solution R for at least one application process (for one substrate) from the bottle 172 storing the resist solution R through the suction pipe 174 to apply the resist solution R. At the time of processing, the resist solution R is sent from the resist pump 176 to the resist nozzle 78 through the discharge pipe or the resist liquid supply pipe 94 at a predetermined pressure, and the resist liquid R is discharged onto the substrate G from the resist nozzle 78 at a predetermined flow rate. It is like that.

The bottle 172 is hermetically sealed, and pressurized gas such as N ₂ gas is supplied at a constant pressure from the gas pipe 178 toward the liquid level in the bottle. The gas pipe 178 is provided with an on-off valve 180 made of an air operated valve, for example.

  A filter 182, a deaeration module 184, and an on-off valve 186 are provided in the middle of the suction pipe 174. The filter 182 removes foreign matter (dust) in the resist solution R sent from the bottle 172, and the degassing module 184 removes bubbles in the resist solution. The on-off valve 186 is composed of, for example, an air operated valve, and turns on (fully opens) or turns off (cuts off) the flow of the resist solution R in the suction pipe 174.

  An open / close valve 188 is provided in the middle of the resist solution supply pipe 94. There is no filter or suckback valve. The on-off valve 188 is composed of, for example, an air operated valve, and turns on (fully opens) or turns off (cuts off) the flow of the resist solution R in the resist solution supply pipe 94. Further, a pressure sensor 195 is also attached to the resist solution supply pipe 94. This pressure sensor 195 comprises a gauge pressure gauge, measures the pressure of the resist solution R in the resist solution supply pipe 94 at the sensor mounting position with reference to the atmospheric pressure, and represents an electric signal (pressure measurement signal) representing the measured pressure value as a gauge pressure. ) Is output. The pressure measurement signal output from the pressure sensor 195 is given to the resist solution supply control unit 196 for feedback control and the like, and is also sent to the main controller 200 (FIG. 14) for setting a discharge pressure waveform to be described later. .

  The resist pump 176 is composed of, for example, a syringe pump, and includes a pump main body 190 having a pump chamber, a piston or plunger 192 for arbitrarily changing the volume of the pump chamber, and a pump drive unit 194 for reciprocating the plunger 192. have.

  The resist solution supply control unit 196 is a local controller, and in response to a command from the main controller 200 (FIG. 14), each unit in the resist solution supply mechanism 170, particularly the pump drive unit 194 of the resist pump 176 and the on-off valves 180, 186, 188 and the like are controlled.

  As shown in FIGS. 3 and 5, the resist coating unit (CT) 40 has a nozzle refresh unit 210 disposed slightly upstream of the resist nozzle 78 in the substrate transport direction (X direction). This nozzle refresh unit 210 is horizontally arranged between a standby position indicated by a solid line in FIG. 5 and a forward movement position indicated by a virtual line (dashed line) 210 ′ along a guide rail (not shown) extending in the X direction. It can be moved. The resist nozzle 78 is moved to the nozzle refresh unit 210 between coating processes or when the coating process is not performed for a while. For this purpose, the resist nozzle 78 is once lifted upward, the nozzle refresh unit 210 is moved (submerged) directly below the resist nozzle 78, and then the resist nozzle 78 is lowered to a predetermined height position to the nozzle refresh unit 210. I try to wear it.

  FIG. 13 shows a configuration in the nozzle refresh unit 210. As shown in the figure, the nozzle refreshing unit 210 has a priming processing unit 212, a solvent atmosphere chamber 214, and a cleaning unit 216 arranged in a horizontal row in the X direction. By combining the vertical movement of the resist nozzle 78 and the horizontal movement of the nozzle refresh unit 210 in the X direction, the resist nozzle 78 can be transferred or positioned to each of the parts 212, 214, and 216.

The cleaning unit 216 has a nozzle cleaning head 218 that moves or scans in the longitudinal direction (Y direction) under the resist nozzle 78 positioned at a predetermined position. The nozzle cleaning head 218 is equipped with a cleaning nozzle 220 and a gas nozzle 222 for spraying a cleaning liquid (for example, thinner) and a drying gas (for example, N ₂ gas) toward the lower end portion of the resist nozzle 78 and the discharge port 78a. In addition, a drain portion 224 is provided for collecting and collecting the cleaning liquid that has fallen on the resist nozzle 78 by vacuum.

  The solvent atmosphere chamber 214 is a length that covers the entire length of the resist nozzle 78 and extends in parallel with the nozzle longitudinal direction (Y direction), and a solvent such as thinner is contained in the chamber. On the upper surface of the solvent atmosphere chamber 214, a V-shaped lid 226 having a slit-like opening 226a extending in the longitudinal direction (Y direction) is attached. When the nozzle portion of the resist nozzle 78 is aligned with the lid 226 from above, only the discharge port 78a and the lower end of the tapered nozzle are exposed to the solvent vapor standing in the room through the opening 226a. Yes. While the coating process is not performed on the stage 76 for a while, the resist nozzle 78 is cleaned by the cleaning unit 216 of the discharge port 78a and the nozzle unit, and then waits in the solvent atmosphere chamber 214.

  In the priming processing unit 212, a columnar priming roller 228 that covers the entire length of the resist nozzle 78 and extends in the horizontal direction (Y direction) is disposed in the solvent bath 230. In the solvent bath 230, a solvent or a cleaning liquid such as a thinner is accommodated at a liquid level such that the lower part of the priming roller 228 is immersed. A rotation support mechanism 232 disposed outside the solvent bath 230 supports the rotation shaft of the priming roller 228 and rotationally drives the priming roller 228. Further, a solvent nozzle 234 for spraying a new solvent onto the outer peripheral surface of the priming roller 228 and a wiper 236 that rubs against the outer peripheral surface of the priming roller 228 are provided in the solvent bath 230 at a position above the cleaning liquid reservoir. Yes.

  FIG. 14 shows a main configuration of a control system in the resist coating unit (CT) 40 of this embodiment. The main controller 200 is composed of a microcomputer, and each part in the unit, in particular, a resist solution supply mechanism 170, a nozzle lifting mechanism 75, a stage substrate floating portion 145, a substrate transport unit 84 (transport drive unit 100, pad suction control unit 115, pad) Actuator 109), carry-in lift pin lift unit 85, carry-out lift pin lift unit 91, nozzle refresh unit 210, and the like are controlled individually and overall (sequence).

  Next, the coating processing operation in the resist coating unit (CT) 40 of this embodiment will be described.

  The main controller 200 takes in and executes a coating processing program stored in a storage medium such as an optical disk in the main memory, and controls a series of programmed coating processing operations.

When the transport device 54 new substrate G (FIG. 1) than the untreated is carried into the carry-area M ₁ stage 76, the lift pins 86 receives the substrate G at the forward position. After conveying device 54 has exited, the lift pins 86 are lowered down to a height position that is floating position H _a for conveying the substrate G (Figure 5). Next, an alignment unit (not shown) is operated, and a pressing member (not shown) is pressed against the floating substrate G from four directions to align the substrate G on the stage 76. When the alignment operation is completed, the pad actuator 109 is actuated immediately after that in the substrate transport section 84, and the suction pad 104 is raised (UP) from the original position (retracted position) to the forward movement position (coupled position). The suction pad 104 is vacuum-on from before, and is bonded by a vacuum suction force as soon as it comes into contact with the side edge of the floating substrate G. Immediately after the suction pad 104 is coupled to the side edge of the substrate G, the alignment unit retracts the pressing member to a predetermined position.

Next, the substrate transport unit 84 moves the slider 98 straight from the transport start point position to the transport direction (X direction) at a relatively high constant speed while holding the side edge of the substrate G by the holding unit 102. Thus straight movement in the conveying direction (X direction) in a state where the substrate G is floated on the stage 76, where the front end of the substrate G has reached the set position or applying scanning start position in the application region M _3, the substrate transport unit 84 stops the substrate transfer in the first stage. At this time, the resist nozzle 78 has already finished the priming process in the priming processing unit 212 of the nozzle refresh unit 210, and a predetermined amount of resist liquid film RF is attached to the lower part of the discharge port 78a and the back surface 78b as shown in FIG. In this state, the apparatus is waiting at a predetermined retreat position set above the application position.

As described above, when the substrate G arrives at the set position in the coating region M ₃ , that is, stops at the coating scanning start position, the nozzle lifting mechanism 75 is operated under the control of the main controller 200 to move the registration nozzle 78 vertically downward. The distance between the nozzle outlet and the substrate G or the coating gap is adjusted to the initial value (for example, 60 μm). Then, as shown in FIG. 16, the resist liquid film RF adhering to the discharge port of the resist nozzle 78 and the lower end of the back surface adheres to the substrate G so as to block the application gap of the set size d (beaded). ) Then, at the same time as the resist solution supply mechanism 95 (FIG. 14) starts to discharge the resist solution R, the substrate transport section 84 also starts the second stage substrate transport, while the nozzle lifting mechanism 75 moves the resist nozzle 78 over the coating gap. The substrate G is raised instantaneously until reaching a set value (for example, 240 μm), and thereafter the substrate G is moved horizontally. In this second stage, that is, the substrate conveyance during coating is performed at a relatively low speed for coating scanning.

Thus, in the coating region M ₃ , the substrate G moves at a constant speed in the transport direction (X direction) in a horizontal posture, and at the same time, the long resist nozzle 78 applies the resist solution R toward the substrate G immediately below. By discharging in a strip shape, a resist coating film RM is formed from the front end side to the rear end side of the substrate G as shown in FIG. As described above, the resist gap meniscus RQ formed in the lower portion of the back surface 78b of the resist nozzle 78 in the application scan is made to be in a horizontal straight line by closing the application gap S with a bead of the resist solution without any gap immediately before the start of the application process. It is possible to form a flat resist coating film RM that is uniform and free of coating unevenness.

When the above-described coating process is completed in the coating region M ₃ , that is, when the rear end portion of the substrate G passes just below the resist nozzle 78, the resist solution supply mechanism 95 finishes discharging the resist solution R from the resist nozzle 78. Let At the same time, the substrate transport unit 84 stops the second stage substrate transport (scanning). Immediately after that, the nozzle lifting mechanism 75 lifts the resist nozzle 78 vertically upward and retracts it from the substrate G. Next, the substrate transport unit 84 starts the third stage substrate transport with a relatively high transport speed. When the substrate G arrives at the conveying end position in the unloading area M _5, the substrate conveying unit 84 to stop the substrate carrying the third stage. Immediately after this, the pad suction control unit 115 stops the supply of vacuum to the suction pad 104, and at the same time, the pad actuator 109 lowers the suction pad 104 from the forward movement position (coupling position) to the original position (retraction position), and the substrate The suction pad 104 is separated from both end portions of G. At this time, the pad suction control unit 115 supplies positive pressure (compressed air) to the suction pad 104 to speed up the separation from the substrate G. Instead, the lift pins 92 rise from the original position below the stage to the forward movement position above the stage in order to unload the substrate G.

Thereafter, the unloader, that is, the transfer arm 74 accesses the unloading area M ₅ , receives the substrate G from the lift pins 92, and unloads it out of the stage 76. The substrate transport unit 84 immediately returns the substrate G to the loading region M ₁ at a high speed when the substrate G is transferred to the lift pins 92. When the processed substrate G is unloaded as described above in the unloading area M ₅ , loading, alignment, or transfer start is performed on the new substrate G to be subjected to the next coating process in the loading area M ₁ . On the other hand, the resist nozzle 78 is moved to the priming processing unit 212 of the nozzle refreshing unit 210 where it undergoes priming processing.

  During the above-described coating process, the controller 200 causes the discharge pressure of the resist nozzle 78 to follow the reference discharge pressure control waveform << SP (t) >> through the resist solution supply mechanism 170, and at the same time, the substrate G through the substrate transport unit 84. The conveyance speed, that is, the scanning speed is made to follow the reference scanning speed control waveform << SV (t) >>. More specifically, in the resist solution supply mechanism 170, the pump drive unit 194 of the resist pump 176 is controlled under the control of the resist solution supply processing unit 196 according to the reference discharge pressure control waveform << SP (t) >> from the controller 200. Causes the plunger 192 to move forward. Further, in the substrate transport section 84, the transport drive section 100 moves the slider 98 straightly under the control of a local controller (not shown) according to the reference scanning speed control waveform << SV (t) >> from the controller 200. Thus, the film thickness characteristics (especially the film thickness uniformity in the transport direction) of the resist coating film RM formed on the substrate G have the reference discharge pressure control waveform << SP (t) >> and the scanning speed control waveform << SV (t ) >> waveform shape and timing.

  Hereinafter, with reference to FIG. 18 to FIG. 28, a method for setting the reference discharge pressure control waveform << SP (t) >> and the reference scanning speed control waveform << SV (t) >> used in the coating process of this embodiment will be described. To do.

In this embodiment, the film thickness of the resist coating film RM formed on the substrate G is theoretically proportional to the discharge flow rate of the resist nozzle 78 (more precisely, the flow rate of the resist solution R at the discharge port 78a), This is inversely proportional to the conveyance speed (scanning speed) of the substrate G passing just below the resist nozzle 78. Therefore, when the time function or waveform of the discharge flow rate and the scanning speed of the resist nozzle 78 are respectively F (t) and V (t), the time function D (t) of the film thickness of the resist coating film RM is expressed by the following equation. The
D (t) = Ka · F (t) / V (t) (1)
Here, Ka is a proportionality constant.

  From the above equation (1), in order to make the film thickness D (t) of the resist coating film RM uniform from the start to the end of the coating scan, the discharge flow rate waveform F of the resist nozzle 78 at each time point or each position of the coating scan. The ratio (F (t) / V (t)) between (t) and the scanning speed waveform V (t) may be constant. In other words, when both waveforms F (t) and V (t) are normalized on the basis of the peak value or the steady value, if the normalized waveforms are closely overlapped (match) on the same time axis, the coating is performed. The ratio F (t) / V (t) between them is constant at each scanning time point or each position, and as a result, the film thickness D (t) is kept constant.

  However, since it is very difficult to directly control the discharge flow rate waveform F (t), it is usual to control the discharge pressure waveform P (t) which is proportional to it instead. 12, a pressure sensor 195 is attached to the resist solution supply pipe 94, and a waveform obtained from the sensor output signal is used as a discharge pressure measurement waveform P (t). However, there is a certain time difference δ between the discharge pressure measurement waveform P (t) obtained from the pressure sensor 195 and the discharge pressure waveform P ′ (t) at the discharge port 78 a of the resist nozzle 78. The time delay δ increases in proportion to the distance between the pressure sensor 195 attached to the resist solution supply pipe 94 and the discharge port 78a of the resist nozzle 78.

Therefore, when replacing the discharge flow rate waveform F (t) with the discharge pressure measurement waveform P (t) in the above equation (1), the time delay δ must be considered as in the following equation (2).
D (t) = Kb · P (t−δ) / V (t) (2)
Here, Kb is a proportionality constant.

  From the above equation (2), in order to make the film thickness D (t) of the resist coating film RM uniform throughout the entire coating scanning time or section, the discharge pressure measurement waveform P (t) obtained from the pressure sensor 115 is Normalize both waveforms P (t) and V (t) by shifting the discharge pressure measurement waveform P (t) backward by the time delay δ on the same time axis between the scanning speed measurement waveform V (t) It can be seen that it is sufficient to have a relationship that the respective normalized waveforms overlap substantially exactly.

  FIG. 18 shows a discharge pressure measurement waveform P (t) obtained from the pressure sensor 115, a virtual discharge flow rate waveform F (t) at the resist nozzle 78, a scanning speed measurement waveform V (t) obtained from the speed sensor 115, and each of them. An example of ideal waveform shapes and timing relationships of the normalized waveforms NP (t), NF (t), and NV (t) is shown. Here, the discharge pressure measurement waveform P (t) follows or depends on the reference discharge pressure control waveform SP (t) given from the main controller 200 to the resist solution supply mechanism 170. The scanning speed measurement waveform V (t) follows or depends on the reference scanning speed control waveform SV (t) given to the substrate transport unit 84 from the main controller 200. Therefore, the reference discharge is performed so that an ideal relative waveform shape and timing as shown in FIG. 18 can be obtained between the measurable discharge pressure measurement waveform P (t) and the scanning speed measurement waveform V (t). If the waveform shape and timing relationship of the pressure control waveform SP (t) and the scanning speed control waveform SV (t) are set, the film thickness uniformity of the resist coating film RM can be improved.

  In this regard, in the substrate transport section 84, the transport drive section 100 moves the slider 96 at a speed almost in accordance with the reference scanning speed control waveform SV (t). Moreover, the response speed of the control is high, and a closed loop control or a feedback control method can be used. Therefore, when setting or correcting the waveform shape of a provisional scanning speed control waveform SV (t), which will be described later, there is no need for a trial-and-error accompanied by measurement, and calculation is usually sufficient.

  On the other hand, in the resist solution supply mechanism 170, the response speed and response linearity of the discharge pressure in the pump main body 190 or the resist solution supply pipe 94 with respect to the movement of the plunger 192 are low, and it is difficult to employ closed-loop feedback control. For this reason, open loop control is usually used. In this case, when the plunger 192 of the resist pump 176 is driven with an ideal trapezoidal discharge pressure control waveform SP (t), the discharge pressure in the resist solution supply pipe 94 rises and falls as shown in FIG. It becomes a dull substantially trapezoidal waveform P (t). Rather, as shown in FIG. 20, when the plunger 192 is driven and controlled with a substantially trapezoidal discharge pressure control waveform SP (t) having an overshoot, the pressure in the resist solution supply pipe 94 and the nozzle discharge port 78a are consequently obtained. Can be made into an ideal trapezoidal waveform P (t).

  The ideal substantially trapezoidal discharge pressure control waveform SP (t) as shown in FIG. 20 cannot be determined or set by calculation, and actually causes the resist solution supply mechanism 170 to perform the resist discharge operation, and the pressure sensor 195 is used. Through monitoring, it is necessary to verify whether the actual discharge pressure measurement waveform P (t) is an ideal trapezoidal wave.

  Therefore, in this embodiment, under the overall control of the main controller 200, the resist nozzle 78 is attached to the cleaning unit 216 of the nozzle refresh unit 210 as shown in FIG. 78 is caused to perform the resist solution discharge operation, and the discharge pressure control waveform SP (t) when the discharge pressure measurement waveform P (t) having an ideal trapezoidal shape is obtained is determined by trial and error, and the calculated discharge pressure control is performed. The waveform SP (t) is determined or set as a temporary discharge pressure control waveform <SP (t)> and stored in the memory. Note that the cleaning unit 216 of the nozzle refresh unit 210 may collect and collect the resist solution discharged from the resist nozzle 78 at the drain unit 224 and operate the cleaning nozzle 220 and the gas nozzle 222 in post-processing.

  On the other hand, the trial and error at this stage is not necessary on the substrate transfer unit 84 side, and the temporary scanning speed control waveform <SV (t)> having an ideal trapezoidal shape is set by calculation in the main controller 200 and stored in the memory. save. At this time, the waveform shape of the provisional scanning speed control waveform <SV (t)> is a discharge pressure measurement waveform P (t) in which the normalized waveform <NV (t)> obtained by normalizing the waveform has an ideal trapezoidal shape. ) May be set so as to substantially match the normalized waveform <NP (t)> obtained by normalizing.

  When the provisional discharge pressure control waveform <SP (t)> and the provisional scanning speed control waveform <SV (t)> are prepared as described above, a simulated application scan as shown in FIG. 21 is performed. In this simulated application scanning, the main controller 200 gives a temporary ejection pressure control waveform <SP (t)> and a temporary scanning speed control waveform <SV (t)> to the resist solution supply mechanism 170 and the substrate transport unit 84, respectively. Then, the resist liquid is discharged to the resist nozzle 78 and at the same time, the transport driving unit 100 is caused to perform scanning motion, and the pressure measurement value and the scanning speed measurement value respectively obtained from the pressure sensor 195 and the speed sensor 115 are taken in at the same time. The discharge pressure measurement waveform P (t) and the scanning speed measurement waveform V (t) are acquired over time.

  At that time, the resist coating operation in the resist solution supply mechanism 170 is performed in the same manner as when the provisional ejection pressure control waveform <SP (t)> is set as described above, and the resist nozzle 78 is replaced by the cleaning unit 216 of the nozzle refresh unit 210. Let them wear it. Therefore, the resist solution discharged from the resist nozzle 78 does not fall on the stage 76. On the other hand, the scanning motion in the substrate transport unit 84 may float and transport the substrate G on the stage 76. However, even if only the slider 98 is moved without loading the substrate G on the stage 76, substantially the same measurement result is obtained. A scanning speed measurement waveform V (t) is obtained. Regarding timing, an appropriate initial time difference may be set between the temporary discharge pressure control waveform <SP (t)> and the temporary scanning speed control waveform <SV (t)>.

FIG. 22 shows an example of the discharge pressure measurement waveform P (t) and the scanning speed measurement waveform V (t) obtained in the simulated application scanning as described above. The main controller 200 normalizes the discharge pressure measurement waveform P (t) and the scanning speed measurement waveform V (t) with the respective peak values or set values P _s and V _s as reference values, and normalizes the discharge pressure measurement normalized. The waveform NP (t) is compared with the normalized scanning speed measurement waveform NV (t) on the same time axis.

A comparison of the normalized waveform together, in particular, both normalized waveform NP (t), NV rising slope of the consistency of (t) (FIG. 23) and falling slope of the consistency (not shown) Pay attention to. In other words, it is ideal that the rising slopes of both normalized waveforms NP (t) and NV (t) match and the falling slopes also match, and if they do not match, they are matched. As shown in FIG. 23, as shown in FIG. 23, the tentative scanning speed control waveform <SV (<(SV (t)) is generally calculated so that the inclination of NV (t) on the scanning speed side matches the inclination of NP (t) on the discharge pressure side. t)> The waveform shape is corrected. However, it is possible to correct the temporary discharge pressure control waveform <SP (t)>. As for the time difference or time delay, if the time delay δ (FIG. 18) of the discharge flow rate waveform F (t) with respect to the discharge pressure measurement waveform P (t) is known, both measurement waveforms P (t), V (t ) Or a temporal scanning speed control waveform <SV for the temporary discharge pressure control waveform <SP (t)> so that the time difference between the normalized waveforms NP (t) and NV (t) becomes the value of δ. (t) Correct the time delay of>.

Next, the provisional scanning speed control waveform <SV (t)> and the provisional discharge pressure control waveform <SP (t)> subjected to the above-described waveform shape correction and time delay correction are used. Such a simulated application scan is performed again. Similarly to the first time, the discharge pressure measurement waveform P (t) and the scanning speed measurement waveform V (t) obtained by the second simulated application scan are normalized, and both normalized waveforms NP (t) , NV (t) are compared on the same time axis. Result of the comparison, both normalized waveform NP (t), if the rising and falling slope or time delay error (difference) is between NV (t), multiplied by the same manner as described above a suitable correction Then, a third simulated application scan is performed.

Thus, each time the simulated application scan is repeated, the gradient and time delay errors become smaller, and the discharge pressure measurement waveform P (t) and the scan speed measurement waveform V (t) are both in the waveform shape and in time difference. For example, the ideal relationship as shown in FIG. 18 is approached, and as a result, the relative waveform shape and the temporary discharge pressure control waveform <SP (t)> and the temporary scanning speed control waveform <SV (t)> The time difference approaches ideal. Then, when the error (difference) in the gradient and the time delay falls within the predetermined allowable values, the simulated application scan is terminated, and the temporary discharge pressure control waveform <SP (t)> and the temporary used for the last simulated application scan are The reference discharge pressure control waveform << SP (t) >> and the reference scan speed control waveform << V (t) >> used in the actual coating process are set based on the scanning speed control waveform <SV (t)>. In other words, the reference ejection is the same as (or corrected appropriately) the waveform shape of the temporary ejection pressure control waveform <SP (t)> and the temporary scanning speed control waveform <SV (t)> used for the last simulated application scan. The waveform shape of the pressure control waveform << SP (t) >> and the reference scanning speed control waveform << SV (t) >>, and the provisional scanning speed control waveform <SV for the provisional discharge pressure control waveform <SP (t)>. The time delay of (t)> may be used as it is (or appropriately corrected) as the time delay of the reference scanning speed control waveform << SV (t) >> relative to the reference discharge pressure control waveform << SP (t) >>.

  Here, with reference to FIG. 24 and FIG. 25, an example of an apparatus configuration and method for obtaining the time delay δ of the discharge flow rate waveform F (t) with respect to the discharge pressure measurement waveform P (t) in this embodiment by actual measurement will be described.

  As shown in FIG. 24, this apparatus configuration example includes an actual discharge start detection unit 240 for optically detecting the timing at which the resist solution actually starts to be discharged from the discharge port 78a of the resist nozzle 78 in the resist solution supply mechanism 170. For example, the cleaning unit 216 of the nozzle refresh unit 210 is provided.

  The actual discharge start detection unit 240 is arranged so that a light projecting unit 242 made of, for example, a light emitting diode or a laser diode and a light receiving unit 244 made of, for example, a photodiode are horizontally opposed to each other at an appropriate position of the drain unit 224 of the cleaning unit 216. Let it attach. When the resist nozzle 78 is positioned in the cleaning unit 216, the light beam LB emitted from the light projecting unit 242 passes through the bottom of the discharge port 78 of the resist nozzle 78 and enters the light receiving unit 244 directly opposite. To do. In this case, the resist nozzle 78 may first be lowered to a position low enough to block the light beam LB, and then slowly lifted from there to stop the nozzle ascending movement at the moment when the light beam LB is released. The signal processing unit 246 monitors the transmission (non-light shielding) / light shielding state of the light beam LB in the vicinity of the nozzle outlet 78 by capturing the output signal of the light receiving unit 244 while causing the light projecting unit 242 to emit the light beam LB. A binary signal having a logical value of H level in the (non-light-shielding) state and L level in the light-shielding state is sent to the main controller 200 as the ejection start detection signal MS.

  As shown in FIG. 24, the main controller 200 gives, for example, a temporary discharge pressure control waveform <SP (t)> to the resist solution supply mechanism 170 in a state where the resist nozzle 78 is positioned in the cleaning unit 216, and performs a resist discharge operation. The pressure measurement value P (t) is received from the pressure sensor 195, and the discharge start detection signal MS is received from the signal processing unit 246 of the actual discharge start detection unit 240. Then, as shown in FIG. 25, at the moment when the resist solution R starts to come out from the discharge port 78a of the resist nozzle 78, the light LB from the light projecting unit 242 is blocked by the resist solution R, and the discharge start detection signal MS is It changes from H level to L level.

  Thus, at the timing when the ejection start detection signal MS changes from the H level to the L level, that is, the timing when the resist solution R starts to be ejected from the ejection port 78a of the resist nozzle 78, the ejection flow rate waveform F (t) at the nozzle ejection port 78a. It can be regarded as the rise start timing.

The main controller 200 calculates a time difference Δt to the point t _b the ejection start detection signal MS from time t _a of the rising start has changed from H level to L level of the discharge pressure measurement waveform P (t) as shown in FIG. 26 The time difference Δt is set as a time delay δ of the discharge flow rate waveform F (t) with respect to the discharge pressure measurement waveform P (t).

  As another example, only the waveform shapes of the reference discharge pressure control waveform << SP (t) >> and the reference scan speed control waveform << SV (t) >> are determined or set in the simulated application scan, and a test application process described later is performed. It is also possible to obtain the optimum time difference between the two reference control waveforms << SP (t) >> and << SV (t) >> or the reference time delay from the actually measured film thickness data.

In this test coating process, the main controller 200 uses the time difference or time delay between the two control waveforms << SP (t) >> and << SV (t) >> as a parameter for the resist solution supply mechanism 170 and the substrate transport unit 84, respectively. The discharge pressure control waveform << SP (t) >> and the reference scanning speed control waveform << SV (t) >> are applied to discharge the resist solution to the resist nozzle 78 and at the same time the test substrate G is floated on the stage 76. The coating process is carried out in accordance with the regular coating process. However, it is not necessary to perform application scanning from end to end of the substrate G. For example, the application scanning may be stopped as soon as the discharge pressure and the scanning speed reach steady values. As a result of this test coating process, a plurality (n) of test coating films RM ₁ , RM ₂ ,... RM _n equal to the number of parameter (time delay) candidate values are formed on the substrate G.

In this case, as the value of the parameter (time delay) is increased, the time delays ΔT ₁ , ΔT ₂ ,... ΔT _n of the normalized waveform NV (t) with respect to the normalized waveform NP (t) as shown in FIG. That is, the time delay of the scanning speed measurement waveform V (t) with respect to the discharge pressure measurement waveforms P (t), P (t),... P (t) increases, and the test application is performed as shown in FIG. In the films RM ₁ , RM ₂ ,... RM _n , the thickness of the coating start portion and the thickness of the coating end portion (not shown) are relatively increased.

  After the test coating process as described above is completed, the test substrate G is subjected to the same post-process as that of the regular coating process, that is, a vacuum drying process and a baking process. Of course, a vacuum drying unit (VD) 42 or a heating unit (HP) 48 can be used for these post-treatments.

Next, the respective film thicknesses of the coating films RM ₁ , RM ₂ ,... RM _n on the test substrate G that has been baked are measured by, for example, an optical or contact needle type film thickness measuring device, in particular, coating scanning. The film thickness distribution characteristic or film thickness uniformity in the direction (X direction) is measured, and the test coating film RM _s having the most excellent film thickness uniformity is determined. Then, the parameter (time delay) value used in the test coating process related to the coating film RM _s is set as an optimum value, and a reference time delay used in the regular coating process is set based on the parameter optimum value. Normally, the parameter optimum value may be used as the reference time delay as it is. Alternatively, it is possible to select two parameter optimum values that are difficult to obtain and use the intermediate values as the reference time delay.

  It is also possible to provide a film thickness measuring device in the resist coating unit (CT) 40, thereby determining the optimum parameter value or the reference time from the test coating process as described above under the control of the main controller 200. It is also possible to perform the entire process up to the delay setting fully automatically.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea. For example, the above-described embodiment is related to the levitation transfer type spinless coating method. However, the present invention places a substrate horizontally on a suction-fixed stage, and forms a long resist nozzle above the substrate. The present invention can also be applied to a spinless coating method in which a resist solution is applied from one end to the other on the substrate while moving in a horizontal direction perpendicular to the longitudinal direction of the nozzle. In that case, when performing the simulation coating scan in the present invention, for example, as shown in FIG. 29, the drain pan 250 for receiving and collecting the resist solution discharged from the resist nozzle 78 can be attached to and detached from the nozzle support portion 252. This can prevent the resist solution from falling on the stage 254. In the illustrated apparatus configuration example, a guide rail 256 extending in the transport direction (X direction) is installed above the fixed suction stage 254, and a nozzle support portion 252 that supports the resist nozzle 78 to be movable up and down is provided along the guide rail 256. I try to move it horizontally. A configuration in which the guide rails 256 are provided on both sides of the stage 254 is also possible.

  In addition to the resist solution, for example, a coating solution such as an interlayer insulating material, a dielectric material, and a wiring material can be used as the processing solution in the present invention, and a developing solution, a rinsing solution, and the like are also possible. The substrate to be processed in the present invention is not limited to an LCD substrate, and other flat panel display substrates, semiconductor wafers, CD substrates, photomasks, printed substrates and the like are also possible.

It is a top view which shows the structure of the application | coating development processing system which can apply this invention. It is a flowchart which shows the process sequence in the said application | coating development processing system. It is a schematic plan view showing the entire configuration of a resist coating unit and a vacuum drying unit in the coating and developing treatment system. It is a perspective view which shows the whole structure of the said resist application unit. It is a schematic front view which shows the whole structure of the said resist application unit. It is a top view which shows an example of the array pattern of the jet nozzle and suction inlet in the stage application | coating area | region in the said resist application unit. It is a partial cross section schematic side view which shows the structure of the board | substrate conveyance part in the said resist application unit. It is an expanded sectional view which shows the structure of the holding | maintenance part of the board | substrate conveyance part in the said resist application unit. It is a perspective view which shows the structure of the pad part of the board | substrate conveyance part in the said resist application unit. It is a perspective view which shows one modification of the holding | maintenance part of the board | substrate conveyance part in the said resist application unit. It is a figure which shows the structure of the nozzle raising / lowering mechanism, compressed air supply mechanism, and vacuum supply mechanism in the said resist application unit. It is a block diagram which shows the structure of the resist liquid supply mechanism in the said resist application unit. It is a partial cross section side view which shows the structure of the nozzle refresh part in the said resist application unit. It is a block diagram which shows the main structures of the control system in the said resist application unit. It is a partial cross section side view which shows the state near the discharge outlet of the resist nozzle which received the priming process in the said resist application unit. It is a perspective view which shows a liquid landing state when a long resist nozzle is lowered | hung to the application | coating start position on a board | substrate after a priming process. It is a side view which shows one step of the regular application | coating scanning in embodiment. It is a wave form diagram which shows the ideal waveform of each part in embodiment. It is a wave form diagram which shows an example of the relationship between the discharge pressure control waveform and discharge pressure measurement waveform in embodiment. It is a wave form diagram which shows another example of the relationship between the discharge pressure control waveform and discharge pressure measurement waveform in embodiment. It is a perspective view which shows the simulation application | coating scanning in embodiment. It is a wave form diagram which shows an example of the discharge pressure measurement waveform obtained by the simulation application | coating scanning in embodiment, and a scanning speed measurement waveform. It is a wave form diagram which shows one method for optimizing the relative waveform shape and timing of a temporary discharge pressure control waveform and a temporary scanning speed control waveform in the simulation application scanning in the embodiment. It is a figure which shows the apparatus structure for calculating | requiring the time delay of the discharge flow volume waveform with respect to a discharge pressure measurement waveform in embodiment by actual measurement. FIG. 25 is a partial enlarged side view showing the operation of the actual application start detection unit in FIG. 24. It is a wave form diagram which shows the method of the signal processing for calculating | requiring the said time delay. It is a wave form diagram which shows the relationship of the time difference of the discharge pressure measurement waveform and scanning speed measurement waveform which were normalized when the value of a parameter (time delay) was changed in the test application processing in an embodiment. It is a figure which shows typically the film thickness characteristic of the coating film obtained on a board | substrate as a result of the said test application | coating process. It is a figure which shows the point of the simulation application | coating scanning at the time of applying this invention to the spinless application | coating method using an adsorption | suction fixed type | mold stage.

Explanation of symbols

40 resist coating unit (CT)
75 Nozzle lifting mechanism 76 Stage 78 Resist nozzle 78a Discharge port 84 Substrate transport unit 100 Transport drive unit 115 Speed sensor 170 Resist liquid supply mechanism 176 Resist pump 195 Pressure sensor 210 Nozzle refresh unit 216 Cleaning unit 224 Drain unit

Claims (8)

A reference scanning speed while a processing liquid is discharged from the nozzle in accordance with a reference discharge pressure control waveform with the substrate to be processed and the discharge port of the long nozzle facing each other substantially horizontally with a small gap. A coating method for forming a coating film of the treatment liquid on the substrate by performing a regular coating scan in which the nozzle is moved in a relatively horizontal direction according to a control waveform,
Temporary scanning speed control waveform preset between the nozzle and the stage while discharging the processing liquid in accordance with the temporary ejection pressure control waveform preset to the nozzle on the stage for supporting the substrate According to the simulated application scanning process for scanning relative movement according to
A discharge pressure measuring step of measuring a discharge pressure of the nozzle during the simulated application scanning step to obtain a discharge pressure measurement waveform;
A scanning speed measurement step of measuring the scanning speed during the simulated application scanning step to obtain a scanning speed measurement waveform;
A normalization step of normalizing the discharge pressure measurement waveform and the scanning speed measurement waveform;
A waveform comparison step of comparing at said normalized discharge pressure measured waveform and each of the rising part and falling part on the same time axis of the normalized scanning speed measurement waveform,
As a result of the comparison performed in the waveform comparison step, when the difference in waveform shape between the discharge pressure measurement waveform and the scanning speed measurement waveform is larger than a predetermined allowable value, the temporary discharge pressure control waveform and A correction step of correcting the waveform shape of at least one of the temporary scanning speed control waveforms, and performing the simulated application scanning step, the discharge pressure measurement step, the normalization step, and the waveform comparison step again;
As a result of the comparison performed in the waveform comparison step, when the difference in waveform shape between the discharge pressure measurement waveform and the scanning speed measurement waveform is smaller than a predetermined allowable value, the temporary discharge pressure control waveform and A control waveform setting step of setting the provisional scanning speed control waveform as the reference discharge pressure control waveform and the reference scanning speed control waveform, respectively . When there is a certain time delay between the discharge pressure measurement waveform and the discharge flow rate waveform of the nozzle, the time difference between the discharge pressure measurement waveform and the scanning speed measurement waveform is substantially equal to the time delay. The coating method according to claim 1, wherein at least one timing of the temporary ejection pressure control waveform and the temporary scanning speed control waveform is corrected so as to be equal . The coating method according to claim 1 , further comprising a step of collecting the processing liquid discharged from the nozzle during the simulated coating scanning step without dropping on the stage. Wherein the relative movement horizontally of the nozzle to the substrate, is carried out by conveying the horizontally floating the substrate on the stage, The coating method according to any one of claims 1-3. Wherein the relative movement horizontally of the nozzle to the substrate, the substrate was fixed on the stage is performed by moving the nozzle in a horizontal direction, according to any one of claims 1 to 3 Application method. A stage for supporting the substrate to be processed substantially horizontally;
A long nozzle for discharging a processing liquid from above the stage toward the stage;
A processing liquid supply mechanism for pumping the processing liquid to the nozzle;
A scanning unit for moving the nozzle in a horizontal direction relative to the stage;
An elevating unit for moving the nozzle in a vertical direction relative to the substrate;
A pressure measuring unit that measures the discharge pressure of the nozzle in the middle of the treatment liquid passage from the treatment liquid supply mechanism to the discharge port of the nozzle;
A scanning speed measuring unit for measuring a scanning speed of relative movement of the nozzle with respect to the stage;
A control unit that receives the discharge pressure measurement value and the scanning speed measurement value from the pressure measurement unit and the scanning speed measurement unit, and controls the processing liquid supply mechanism, the scanning unit, and the elevating unit;
Under the control of the control unit, the nozzle and the stage are scanned by the scanning unit while the processing liquid is ejected in accordance with a temporary ejection pressure control waveform preset on the nozzle on the stage by the processing liquid supply mechanism. In accordance with a provisional scanning speed control waveform set in advance with
The discharge pressure measurement waveform is obtained by measuring the discharge pressure of the nozzle through the pressure measurement unit, and the scanning speed measurement waveform is obtained by measuring the scanning speed of the relative movement through the scanning speed measurement unit,
In the control unit, the discharge pressure measurement waveform and the scanning speed measurement waveform are normalized, and the rising part and the falling part of the normalized discharge pressure measurement waveform and the normalized scanning speed measurement waveform are respectively set. Compare on the same time axis,
When the waveform shape difference between the discharge pressure measurement waveform and the scanning speed measurement waveform is larger than a predetermined allowable value in the waveform comparison, the temporary discharge pressure control waveform and the temporary scanning speed control waveform Correcting at least one of the waveform shapes, and discharging the treatment liquid by the treatment liquid supply mechanism under the control of the control unit using the provisional discharge pressure control waveform and the provisional scanning speed control waveform after the correction. The relative movement scanning by the scanning unit is performed again, and the discharge pressure measurement waveform and the scanning speed measurement waveform are obtained again through the pressure measurement unit and the scanning speed measurement unit, and the discharge pressure measurement is performed in the control unit. Renormalize the waveform and the scanning speed measurement waveform respectively, and perform the waveform comparison again on the same time axis,
In the waveform comparison, when the difference in waveform shape between the discharge pressure measurement waveform and the scan speed measurement waveform is smaller than a predetermined allowable value, the temporary discharge pressure control waveform and the temporary scan speed control waveform are Set as reference discharge pressure control waveform and reference scan speed control waveform respectively,
Under the control of the control unit, the substrate and the discharge port of the nozzle are opposed substantially horizontally with a small gap on the stage by the elevating unit, and the reference discharge pressure is set by the processing liquid supply mechanism. While the processing liquid is ejected from the nozzle according to the control waveform, the nozzle is moved relatively in the horizontal direction according to the reference scanning speed control waveform by the scanning unit, and the coating film of the processing liquid is formed on the substrate. A coating device for forming. Having a processing liquid recovery section for recovering the process liquid discharged from the nozzle in accordance with the discharge pressure control waveform of the temporary without lowering the stage, coating apparatus according to claim 6. The stage is provided with a floating region for floating the substrate in the air by the force of air pressure,
The scanning unit includes a substrate transfer unit that holds a substrate that floats on a floating region of the stage and transfers the substrate in a predetermined transfer direction.
The coating device according to claim 6 or 7.

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