JP4541190B2 - Substrate processing apparatus and processing liquid supply method - Google Patents

Description

  The present invention relates to a technique for discharging a processing liquid from a slit nozzle at a constant discharge speed.

  In the substrate manufacturing process, a substrate processing apparatus is used in which a resist solution (processing solution) is ejected from a slit nozzle and the slit nozzle and the substrate are relatively moved to apply the resist solution to the surface of the substrate. In such a substrate processing apparatus, since the film thickness is determined by the supply amount of the resist solution supplied to the slit nozzle, it is important to control the discharge flow rate of the pump that supplies the resist solution (control of the discharge speed of the slit nozzle). It is a problem.

  Conventionally, as a pump for supplying a resist solution to a slit nozzle, a tube pump for discharging a resist solution stored in the tube by squeezing the tube (reducing the internal volume) by a driving mechanism has been proposed. . An example of such a tube pump is described in Patent Document 1. The tube pump has an advantage that stable discharge is possible with less pulsation as compared with a syringe pump, and is a pump suitable for coating processing in a substrate processing apparatus.

  In the tube pump, the discharge flow rate of the resist solution depends on the reduction amount of the internal volume of the tube because of the structure. As described above, in the substrate processing apparatus using the slit nozzle, in order to make the coating film thickness uniform in the coating process, it is necessary to make the discharge speed of the pump constant. That is, in the tube pump, it is necessary to make the decrease rate of the internal volume of the tube constant.

JP 2004-281640 A

  However, the tube pump has a problem that even if the drive mechanism is driven at a constant speed, the reduction rate of the internal volume of the tube is not constant. That is, when the drive mechanism is driven at a constant speed, there is a problem that the discharge speed is substantially increased.

  Even if it is not a tube pump, there is a similar problem when a regulator or a filter is provided in the flow path of the resist solution.

  The present invention has been made in view of the above problems, and an object of the present invention is to control a pump (drive mechanism) so that a discharge speed is substantially constant.

  In order to solve the above problems, the invention of claim 1 is a substrate processing apparatus for forming a film of a predetermined processing solution on a substrate, the holding means for holding the substrate, and the substrate held by the holding means. A slit nozzle that discharges a predetermined processing liquid; and a supply unit that supplies the predetermined processing liquid to the slit nozzle. The supply unit stores a predetermined processing liquid therein; and The drive speed of the drive means is gradually increased in a constant speed period in which the volume change means for changing the internal volume, the drive means for driving the volume change means, and the discharge speed from the slit nozzle are substantially maintained at the target discharge speed. And a control means for controlling the drive means so as to be lowered.

  According to a second aspect of the present invention, there is provided the substrate processing apparatus according to the first aspect of the invention, wherein the driving speed is substantially decelerated within the constant speed period.

  The invention according to claim 3 is the substrate processing apparatus according to claim 1 or 2, wherein the control means temporarily sets the drive speed during an acceleration period in which the discharge speed is accelerated to the target discharge speed. After accelerating to a target speed, the drive means is controlled to decelerate to a target speed lower than the temporary target speed.

  According to a fourth aspect of the present invention, there is provided the substrate processing apparatus according to any one of the first to third aspects, wherein the volume changing means is configured such that the first bellows and the second bellows having different internal dimensions are connected in communication. A container that accommodates the tube member therein, and a link member that is fixed to the container and driven by the driving means at the driving speed, and is provided between the inner surface of the container and the outer surface of the tube member. The indirect liquid is sealed in the space.

  According to a fifth aspect of the present invention, a predetermined processing liquid stored in the tube member is slit by driving a volume changing means for changing the internal volume of the hollow tube member and reducing the internal volume. A treatment liquid supply method for supplying a nozzle to a nozzle, wherein a starting step of starting driving of the volume changing unit and a discharge speed from the slit nozzle are reduced by gradually decreasing the driving speed of the volume changing unit. The method includes a supply step of supplying the predetermined processing liquid so as to be kept substantially constant, and a stop step of stopping driving of the volume changing means.

  Further, the invention of claim 6 is a processing liquid supply method according to the invention of claim 5, wherein an acceleration step of accelerating the drive speed to a temporary target speed by starting the start step, and the acceleration The method further includes a decelerating step of decelerating the drive speed to the target speed after the drive speed reaches the temporary target speed by a step.

  According to the first to sixth aspects of the present invention, the uniformity of the coating film thickness is improved by gradually decreasing the driving speed in a constant speed period in which the discharge speed from the slit nozzle is substantially maintained at the target discharge speed. be able to.

  In the invention according to claim 3 or 6, in the acceleration period in which the discharge speed is accelerated to the target discharge speed, the drive speed is accelerated to the temporary target speed and then decelerated to a target speed lower than the temporary target speed. Response delay can be suppressed.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.

<1. First Embodiment>
FIG. 1 is a perspective view schematically showing a substrate processing apparatus 1 according to an embodiment of the present invention. In FIG. 1, for the sake of illustration and explanation, the Z-axis direction is defined as the vertical direction and the XY plane is defined as the horizontal plane, but these are defined for convenience in order to grasp the positional relationship. The directions described below are not limited. The same applies to the following figures.

  The substrate processing apparatus 1 is roughly divided into a main body 2 and a control unit 8, and a square glass substrate for manufacturing a screen panel of a liquid crystal display device is a substrate to be processed (hereinafter simply referred to as “substrate”) 90. In a process of selectively etching an electrode layer or the like formed on the surface of the substrate 90, the coating apparatus is configured to apply a resist solution as a processing solution to the surface of the substrate 90. Therefore, in this embodiment, the slit nozzle 41 discharges the resist solution. In addition, the substrate processing apparatus 1 can be modified and used not only as a glass substrate for a liquid crystal display device but also as a device for applying a processing liquid to various substrates for a flat panel display.

  The main body 2 includes a stage 3 that functions as a holding table for mounting and holding the substrate 90 and also functions as a base for each attached mechanism. The stage 3 is made of, for example, an integral stone having a rectangular parallelepiped shape, and its upper surface (holding surface 30) and side surfaces are processed into flat surfaces.

  The upper surface of the stage 3 is a horizontal plane and serves as a holding surface 30 for the substrate 90. A number of vacuum suction ports (not shown) are formed on the holding surface 30 in a distributed manner, and the substrate 90 is held in a predetermined horizontal position by sucking the substrate 90 while the substrate processing apparatus 1 processes the substrate 90. To do. The holding surface 30 is provided with a plurality of lift pins LP that can be moved up and down by driving means (not shown) at appropriate intervals. The lift pins LP are used to push up the substrate 90 when the substrate 90 is removed.

  A pair of running rails 31 extending in parallel in a substantially horizontal direction are fixed to both ends of the holding surface 30 across the holding area of the substrate 90 (region where the substrate 90 is held). The traveling rail 31, together with a support block (not shown) fixed to the lowermost part of both ends of the bridge structure 4, guides the movement of the bridge structure 4 (defines the moving direction to a predetermined direction), and holds the bridge structure 4 on the holding surface A linear guide supported above 30 is configured.

  On the holding surface 30 of the main body 2, an opening 32 is provided on the (−X) direction side of the holding area. The opening 32 has a longitudinal direction in the Y-axis direction similar to the slit nozzle 41, and the longitudinal length is substantially the same as the longitudinal direction length of the slit nozzle 41.

  Although not shown in FIG. 1, in the main body 2 below the opening 32, a pre-coating mechanism for normalizing the state of the slit nozzle 41 and drying of the waiting slit nozzle 41 are suppressed. There are standby pods and so on. The standby pot is also used when the resist solution is discharged from the resist pump 65 (FIG. 2).

  Above the stage 3, a bridging structure 4 is provided that extends substantially horizontally from both sides of the stage 3. The bridging structure 4 is mainly composed of, for example, a nozzle support portion 40 that uses carbon fiber reinforced resin as an aggregate, and lifting mechanisms 43 and 44 that support both ends thereof.

  A slit nozzle 41 is attached to the nozzle support portion 40. In FIG. 1, a supply mechanism 6 (FIG. 2) for supplying a resist solution toward the slit nozzle 41 is connected to a slit nozzle 41 having a longitudinal direction in the Y-axis direction.

  The slit nozzle 41 scans the surface of the substrate 90 and discharges the supplied resist solution to a predetermined region (hereinafter referred to as “resist application region”) on the surface of the substrate 90, thereby resisting the substrate 90. Apply liquid. The resist coating region is a region on the surface of the substrate 90 where the resist solution is to be applied, and is usually a region obtained by excluding a region having a predetermined width along the edge from the entire area of the substrate 90. is there.

  The elevating mechanisms 43 and 44 are divided on both sides of the slit nozzle 41 and connected to the slit nozzle 41 by the nozzle support portion 40. The elevating mechanisms 43 and 44 are mainly composed of AC servomotors 43 a and 44 a and a ball screw (not shown), and generate elevating driving force for the bridging structure 4 based on a control signal from the control unit 8. Thereby, the raising / lowering mechanisms 43 and 44 raise / lower the slit nozzle 41 in translation. The lifting mechanisms 43 and 44 are also used to adjust the posture of the slit nozzle 41 in the YZ plane.

  A pair of AC coreless linear motors (hereinafter simply referred to as “stator”) and a “moving element 50b” and “stator 51a” and “moving element 51b” are provided at both ends of the bridging structure 4 along the edges on both sides of the stage 3, respectively. , Abbreviated as “linear motor”.) 50 and 51 are fixed. In addition, linear encoders 52 and 53 each having a scale portion and a detector are fixed to both ends of the bridging structure 4. The linear encoders 52 and 53 detect the positions of the linear motors 50 and 51. The linear motors 50 and 51 and the linear encoders 52 and 53 mainly constitute a moving mechanism for moving the bridge structure 4 on the stage 3 while being guided by the traveling rail 31. The control unit 8 controls the operation of the linear motors 50 and 51 based on the detection results from the linear encoders 52 and 53, and controls the movement of the bridging structure 4 on the stage 3, that is, the scanning of the substrate 90 by the slit nozzle 41. To do.

  FIG. 2 is a diagram illustrating a configuration of the supply mechanism 6. The supply mechanism 6 includes a resist bottle 60 for storing a resist solution, a supply pipe 61, a discharge pipe 62, open / close valves 63 and 64, a resist pump 65, and a drive mechanism 66.

  The supply pipe 61 is a pipe for supplying the resist solution toward the resist pump 65. When the open / close valve 63 that opens and closes the supply pipe 61 according to a control signal from the control unit 8 is in an open state, the resist solution is sucked and supplied from the resist bottle 60 to the resist pump 65.

  The discharge pipe 62 is a pipe for supplying the resist solution toward the slit nozzle 41. When the opening / closing valve 64 that opens and closes the discharge pipe 62 according to a control signal from the control unit 8 is in an open state, the resist solution is discharged from the resist pump 65 and supplied to the slit nozzle 41 through the discharge pipe 62. The

  FIG. 3 is a diagram showing details of the registration pump 65 and the drive mechanism 66. In FIG. 3, a cross section of the resist pump 65 is shown.

  The resist pump 65 includes a pair of lids 650, a first bellows 651, a second bellows 652, a joining member 653, and a tube 654 that are arranged vertically. Further, the resist pump 65 is provided with a suction port 655 that serves as an inlet for the resist solution when the resist solution is sucked and a discharge port 656 that serves as an exit for the resist solution when the resist solution is discharged. The suction port 655 is connected to the resist bottle 60 through the supply pipe 61, the discharge port 656 is connected to the slit nozzle 41 through the discharge pipe 62, and the suction port 655 is positioned below the discharge port 656. Is installed.

  The first bellows 651 and the second bellows 652 are configured by members that can be expanded and contracted along the Z-axis direction, and the end portion on the (−Z) side of the first bellows 651 via the joining member 653, and the second The end of the bellows 652 on the (+ Z) side is fixed to each other, and the inside communicates with each other. Further, both ends of the first bellows 651 and the second bellows 652 are supported by a rigid body (not shown) via a lid 650 so that the total length (L in the figure) is constant. Since the inner diameter area of the first bellows 651 (the area of the surface perpendicular to the Z-axis) is smaller than the inner diameter area of the second bellows 652, the first bellows 651 extends and the second bellows 652 extends. The volume of the resist pump 65 can be changed by changing the state between the two.

  A tube 654 is disposed inside the first bellows 651 and the second bellows 652. The tube 654 is formed of a substantially tubular and deformable member, and both ends thereof are connected to the suction port 655 and the discharge port 656, respectively. That is, the tube 654 constitutes a resist solution flow path. In the substrate processing apparatus 1 in the present embodiment, as shown in FIG. 3, the tube 654 is disposed in a substantially vertical direction along the Z axis.

  An indirect liquid LQ is enclosed in a space surrounded by the first and second bellows 651 and 652 and the tube 654. As the indirect liquid LQ, a liquid having a low volume change rate with respect to changes in pressure, temperature and the like is used. Thereby, even if the first bellows 651 and the second bellows 652 are deformed by expansion and contraction, the volume of the indirect liquid LQ hardly changes.

  With such a configuration, in the substrate processing apparatus 1 in the present embodiment, when the first bellows 651 extends (when the bonding member 653 is moved downward), the first and second bellows 651 of the resist pump 65 are arranged. The internal volume of 652 is reduced. Therefore, the enclosed indirect liquid LQ is pressurized. Since the indirect liquid LQ is a liquid whose volume hardly decreases even when pressurized, the tube 654 is contracted (squeezed) by the pressurized indirect liquid LQ, and the inside of the tube 654 is pressurized.

  At this time, if the opening / closing valve 64 is opened, the resist solution in the tube 654 is discharged from the discharge port 656 and fed toward the slit nozzle 41 via the discharge pipe 62. At this time, if the open / close valve 63 is closed, the resist solution in the tube 654 does not flow backward from the suction port 655.

  On the other hand, when the second bellows 652 is extended (when the joining member 653 is moved upward), the internal volumes of the first and second bellows 651 and 652 of the resist pump 65 are increased. Accordingly, the enclosed indirect liquid LQ is decompressed. Since the indirect liquid LQ is a liquid whose volume hardly increases even when the pressure is reduced, the tube 654 expands due to the pressure reduction of the indirect liquid LQ, and the inside of the tube 654 is decompressed.

  At this time, if the opening / closing valve 63 is opened, the resist solution in the resist bottle 60 is sucked into the tube 654 from the suction port 655 through the supply pipe 61. At this time, if the opening / closing valve 64 is closed, the resist solution in the discharge pipe 62 does not flow back into the tube 654 from the discharge port 656.

  As described above, the resist pump 65 can repeatedly perform the resist solution suction operation and the discharge operation by reciprocating the bonding member 653 along the Z-axis direction, and has a function of feeding the resist solution. ing. That is, the first bellows 651 and the second bellows 652 mainly correspond to volume changing means in the present invention.

  FIG. 4 is a diagram showing details of the drive mechanism 66. The drive mechanism 66 includes a base 660, a drive motor 661, a ball screw 662, a nut member 663, an attachment member 664, a guide 665, a bearing member 666, and a guide fixing member 667. With such a configuration, the drive mechanism 66 drives the first bellows 651 and the second bellows 652 (joining member 653) of the registration pump 65 along the Z-axis direction.

  In the substrate processing apparatus 1 according to the present embodiment, the rotational driving force generated by the driving motor 661 is converted into a linear driving force by a configuration mainly composed of the ball screw 662 and the nut member 663 to obtain a driving force.

  The base 660 is a member for mounting and integrating the components of the drive mechanism 66. Although not shown in FIG. 4, the base 660 is appropriately provided with a member for fixing to the nozzle support portion 40. Thus, driving accuracy can be improved by fixing to the nozzle support part 40 in the state which made each structure of the drive mechanism 66 integral. The base 660 is fixed to the nozzle support 40 so that a guide direction by a guide 665 described later is along the Z axis.

  The drive motor 661 is a DD (Direct Drive) motor with high speed accuracy at low speed rotation (500 rpm or less). By adopting the DD motor as the drive motor 661 in this way, the substrate processing apparatus 1 in the present embodiment can directly connect the ball screw 662 and the drive motor 661 without using a reduction gear. In addition to being able to reduce the cost and size, it is possible to prevent the feeding accuracy of the nut member 663 from being lowered due to the accuracy of the reduction gear, backlash, or the like. Furthermore, since the rigidity value can be maintained as compared with the case where a timing belt or the like is used, it is possible to suppress a reduction in rotational unevenness and control characteristics (such as a response delay with respect to a rapid speed change).

  Although not shown in FIG. 4, the drive motor 661 is connected to the control unit 8 in a state where signals can be transmitted and received, and the rotation amount and the rotation speed are determined according to the control signal from the control unit 8. Can be controlled. A method for controlling the drive motor 661 will be described later.

  The ball screw 662 is a cylindrical rod-shaped member having a central axis P, and is attached to the base 660 by a pair of bearing members 666 attached to both ends. In addition, a spiral lead for screwing with the nut member 663 is provided on the cylindrical surface of the ball screw 662.

  The nut member 663 is provided with a through-hole for screwing with the ball screw 662, and a spiral groove is formed on the inner wall of the through-hole so as to engage with a lead provided on the ball screw 662. An attaching member 664 is fixed to the nut member 663, and the attaching member 664 is attached to the joining member 653 of the resist pump 65.

  When the ball screw 662 is screwed into the through hole of the nut member 663 while rotating, the nut member 663 moves linearly in a predetermined direction with respect to the ball screw 662 along the central axis P. Since the nut member 663 and the joining member 653 are connected via the attachment member 664, when the nut member 663 is moved as described above, the joining member 653 moves in the same direction in conjunction with each other. In this way, in the substrate processing apparatus 1, the rotational driving force around the central axis P by the driving motor 661 is converted into the linear driving force of the registration pump 65 in the Z-axis direction. In the following description, the rotation direction of the drive motor 661 when the nut member 663 moves toward the drive motor 661 along the ball screw 662 is referred to as a “forward direction”.

  Further, the nut member 663 is provided with a guide portion (not shown) for receiving the guide 665. The guide portion is provided with a plurality of balls, and the nut member 663 and the guide 665 are able to suppress friction when the nut member 663 moves by receiving the balls through the balls. Also, resin spacers or spacer balls are disposed between the balls. Thereby, since the vibration and feed unevenness accompanying rolling and circulation of the ball can be suppressed, the speed accuracy of the nut member 663 can be improved.

  The guide 665 is assembled and fixed to the base 660 together with the ball screw 662 by a pair of guide fixing members 667 while receiving a guide portion (not shown) of the nut member 663. The guide 665 has a linear guide shaft J, and by receiving the nut 663, the moving direction of the nut member 663 that moves by the rotation of the ball screw 662 is defined in a direction along the guide shaft J. It has a function.

  As described above, the nut member 663 moves along the central axis P of the ball screw 662 as the ball screw 662 rotates. However, the position of the central axis P varies slightly due to the drive vibration of the ball screw 662 and the like. Therefore, the moving direction of the nut member 663 cannot be accurately defined only by the ball screw 662.

  On the other hand, since the guide 665 is stationary, the position of the guide axis J is more stable than the position of the central axis P. Therefore, the movement direction of the nut member 663 of the drive mechanism 66 is defined by the guide shaft J, so that the movement speed and the accuracy of the movement direction of the nut member 663 are improved.

  The bearing member 666 is provided with a bearing for support (not shown), and the ball screw 662 contacts the bearing. Accordingly, the ball screw 662 can be attached to the base 660 without hindering the rotation of the ball screw 662 around the central axis P. In addition, in order to improve the rotational rigidity of the ball screw 662, the said bearing uses the member which has appropriate rigidity etc. in consideration of an axial load. Further, by using a relatively large bearing, the stability of rotation of the ball screw 662 can be improved.

  Returning to FIG. 1, the control unit 8 includes a calculation unit 80 that processes various data according to a program and a storage unit 81 that stores the program and various data. Further, on the front surface, an operation unit 82 for an operator to input necessary instructions to the substrate processing apparatus 1 and a display unit 83 for displaying various data are provided.

  The control unit 8 is electrically connected to each mechanism attached to the main body 2 by a cable (not shown) in FIG. The calculation unit 80 of the control unit 8 is configured to move up and down by the elevating mechanisms 43 and 44 based on input signals from the operation unit 82 and signals from various sensors (for example, linear encoders 52 and 53), linear motor 50, The scanning operation by 51 is controlled.

  In the configuration of the control unit 8, specific examples of the storage unit 81 include a RAM that temporarily stores data, a read-only ROM, and a magnetic disk device. However, the storage unit 81 may be replaced by a storage medium such as a portable magneto-optical disk or a memory card and a reading device thereof. The operation unit 82 corresponds to buttons and switches (including a keyboard and a mouse), but may have a function of the display unit 83 such as a touch panel display. The display unit 83 corresponds to a liquid crystal display or various lamps.

  The above is the description of the structure and function of the substrate processing apparatus 1 in the present embodiment. Next, after a conventional supply process is outlined, the supply process in the present embodiment will be described.

  FIG. 5 is a diagram showing the rotational speed r of the motor in the conventional supply process control. FIG. 6 is a diagram showing the discharge speed v when the rotation speed r is controlled as shown in FIG. The period from the start of driving the pump until the discharge speed v reaches the target discharge speed v0 is an acceleration period for accelerating the discharge speed v. In addition, a period from when the acceleration period ends to when the slit nozzle moves to a predetermined position (position where ejection is stopped) is a constant speed period in which the discharge speed v is maintained at a substantially constant speed. Further, the target discharge speed v0 in FIG. 6 is a discharge speed for obtaining an ideal coating film thickness.

  The motor for driving the pump is controlled by the rotation speed n input within a predetermined time by the control signal. That is, the motor control parameter is usually the rotational speed r. Accordingly, in a supply mechanism using a general pump, the relationship between the discharge speed v of the slit nozzle and the rotation speed r of the motor is obtained through experiments, and the resist solution is obtained by the rotation speed r corresponding to the desired discharge speed v. A method of controlling the supply is adopted.

  In the conventional supply process, control is performed so that the rotational speed r of the motor is set to the target rotational speed r0 simultaneously with the start of supply of the resist solution. As a result, as shown in FIG. 5, the rotational speed r of the motor is accelerated substantially linearly, and reaches a target rotational speed r0 after a predetermined time has elapsed.

  The target rotation speed r0 is a value set according to the target discharge speed v0 at which an ideal film thickness is obtained. Therefore, in the conventional supply process, when the rotational speed r of the motor reaches the target rotational speed r0, the resist solution is supplied to the slit nozzle by controlling to maintain the constant speed rotation as it is.

  When the slit nozzle moves to a predetermined position, the rotation speed r of the motor is reduced and the rotation of the motor is stopped. Thereby, the supply of the resist solution to the slit nozzle is stopped, and the supply process ends. Note that when the supply to the slit nozzle is stopped, the discharge from the slit nozzle is stopped.

  However, when a tube pump is used, or when a regulator, a filter, or the like is arranged in the resist solution flow path, a situation occurs in which the rotational speed r is not directly reflected on the actual discharge speed v.

  For example, when attention is paid at the start of rotation, since the discharge speed v does not completely follow the rotation speed r, a response delay occurs, and the discharge speed v rises gently. That is, even when the motor rotation speed r reaches the target rotation speed r0, the discharge speed v has not yet reached the target discharge speed v0, and the acceleration period has not ended. In the conventional supply process, since the acceleration at the rotational speed r is stopped in this state (transition to constant speed rotation), the time until the discharge speed v reaches the target discharge speed v0 is further delayed. That is, there is a problem that the acceleration period becomes longer.

  Further, as shown in FIG. 6, the discharge speed v gradually increases while rotating at a constant rotation speed at the target rotation speed r0, and the film thickness becomes nonuniform in the resist coating region. That is, there is a problem that the discharge speed v is not substantially constant during the constant speed period. This occurs because the discharge speed v changes between the initial stage and the final stage of discharge even if a constant rotational speed r is continuously applied to the motor. The discharge speed v is a value that is difficult to observe in real time, and such a phenomenon has not been clarified so far.

  The supply process in the present embodiment for solving the problems of the conventional supply process as described above will be described below.

  FIG. 7 is a flowchart showing a resist solution supply process in the substrate processing apparatus 1. FIG. 8 is a diagram showing the rotational speed r of the drive motor 661 in the supply process. Further, FIG. 9 is a diagram showing the discharge speed v when the rotation speed r is controlled as shown in FIG.

  In the supply process in the present embodiment, first, the drive motor 661 starts to rotate in the forward rotation direction (step S1). As a result, the nut member 663 starts moving in the (−Z) direction, the first bellows 651 expands, and the second bellows 652 contracts.

  At this time, as shown in FIG. 8, the control unit 8 controls the drive motor 661 so as to accelerate the rotational speed r to the temporary target rotational speed r1 higher than the target rotational speed r0. That is, while accelerating the rotational speed r of the drive motor 661 (step S2), it is determined whether or not the temporary target rotational speed r1 has been reached (step S3).

  When the temporary target rotational speed r1 is reached (Yes in step S3), it is determined whether or not the predetermined time T0 has elapsed (step S5) while rotating at a constant target rotational speed r1 (step S4). Here, the predetermined time T0 is a time from when the rotational speed r of the drive motor 661 reaches the temporary target rotational speed r1 to immediately before the discharge speed v reaches the target discharge speed v0. It is assumed that the temporary target rotational speed r1 and the predetermined time T0 are obtained in advance by experiments.

  When the predetermined time T0 has elapsed (Yes in step S5), the control unit 8 decelerates the rotational speed r of the drive motor 661 to the target rotational speed r0 (step S6). Since the discharge speed v also increases during this deceleration period, the discharge speed v does not exceed the target discharge speed v0 until step S6 is completed in consideration of the increase in the discharge speed v at this time. In addition, the above-mentioned “predetermined time T0” is determined. Therefore, after step S6 is executed, the discharge speed v reaches the target discharge speed v0, and the acceleration period ends.

  Thus, in the substrate processing apparatus 1 according to the present embodiment, at the start of the supply process, the rotational speed r of the drive motor 661 is set to a temporary target rotational speed r1 that is faster than the target rotational speed r0. As a result, as shown in FIG. 9, the rising of the discharge speed v of the resist pump 65 becomes good, and the acceleration period is shortened compared to the example shown in FIG.

  When the acceleration period ends and the constant speed period starts, the controller 8 determines whether or not the slit nozzle 41 has moved to a predetermined position while reducing the rotational speed r of the drive motor 661 equally (step S7). Is determined (step S8). As a result, while the slit nozzle 41 scans the resist coating area, the rotational speed r of the drive motor 661 is mainly reduced at an equal speed.

  As described above, in the substrate processing apparatus 1 according to the present embodiment, after the discharge speed v reaches an appropriate speed, the rotational speed r of the drive motor 661 is not kept constant, but a predetermined acceleration α (α is Decelerate at a negative number). That is, the drive motor 661 is controlled so as to gradually decrease the rotation speed r in a constant speed period in which the discharge speed v from the slit nozzle 41 is substantially maintained at the target discharge speed v0.

  As a result, the rotational speed r decreases by the amount corresponding to the increase in the discharge speed v, so that the discharge speed v can be substantially maintained at the target discharge speed v0. Therefore, the uniformity of the coating film thickness is improved. It is assumed that the predetermined acceleration α is obtained in advance by experiments.

  When the slit nozzle 41 moves to a predetermined position (Yes in step S8), the control unit 8 stops the rotation of the drive motor 661 (step S9). Thereby, the discharge of the resist solution from the resist pump 65 is stopped, and the supply process is ended.

  As described above, the substrate processing apparatus 1 according to the present embodiment is driven so as to gradually decrease the rotation speed r during the constant speed period in which the discharge speed v from the slit nozzle 41 is substantially maintained at the target discharge speed v0. By controlling the mechanism 66, the uniformity of the coating film thickness can be improved.

  Further, in the acceleration period in which the discharge speed v is accelerated to the target discharge speed v0, the rotation speed r is accelerated to the temporary target rotation speed r1, and then decelerated to the target rotation speed r0 lower than the temporary target rotation speed r1. By controlling the drive mechanism 66, response delay can be suppressed.

<2. Modification>
Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made.

  For example, the drive motor 661 used for the drive mechanism 66 in the present embodiment is not limited to the DD motor, and other types of motors may be used as long as they have high speed accuracy (1% or less at 100 rpm) at low speed rotation. May be used.

  In addition, when using a motor with insufficient speed accuracy at low speed, it may be used in combination with a so-called high-accuracy reducer with little backlash, but in this case, the motor has a high resolution (217 p / rev or more). ) Is preferably used.

1 is a perspective view schematically showing a substrate processing apparatus according to an embodiment of the present invention. It is a figure which shows the structure of a supply mechanism. It is a figure which shows the detail of a resist pump and a drive mechanism. It is a figure which shows the detail of a drive mechanism. It is a figure which shows the rotational speed r of the motor in the conventional supply process control. It is a figure which shows the discharge speed v at the time of controlling the rotational speed r as shown in FIG. It is a flowchart which shows the supply process of the resist liquid in a substrate processing apparatus. It is a figure which shows the rotational speed r of the drive motor in a supply process. It is a figure which shows the discharge speed v when the rotational speed r is controlled like FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate processing apparatus 41 Slit nozzle 50, 51 Linear motor 6 Supply mechanism 65 Registration pump 651 1st bellows 652 2nd bellows 653 Joining member 654 Tube 66 Drive mechanism 661 Drive motor 662 Ball screw 663 Nut member 664 Mounting member 8 Control part 90 Substrate LQ Indirect liquid r Rotational speed r0 Target rotational speed r1 Temporary target rotational speed v Discharge speed v0 Target discharge speed α Acceleration

Claims (6)

A substrate processing apparatus for forming a film of a predetermined processing solution on a substrate,
Holding means for holding the substrate;
A slit nozzle for discharging a predetermined processing liquid onto the substrate held by the holding means;
Supply means for supplying a predetermined processing liquid to the slit nozzle;
With
The supply means includes
A tube member for storing a predetermined processing liquid therein;
Volume changing means for changing the internal volume of the tube member;
Driving means for driving the volume changing means;
Control means for controlling the drive means so as to gradually reduce the drive speed of the drive means in a constant speed period in which the discharge speed from the slit nozzle is substantially maintained at the target discharge speed;
A substrate processing apparatus comprising: The substrate processing apparatus according to claim 1,
The substrate processing apparatus is characterized in that the driving speed is substantially decelerated within the constant speed period. The substrate processing apparatus according to claim 1, wherein:
In the acceleration period in which the discharge speed is accelerated to the target discharge speed, the control unit accelerates the drive speed to the temporary target speed and then reduces the drive speed to a target speed lower than the temporary target speed. A substrate processing apparatus characterized by controlling means. A substrate processing apparatus according to any one of claims 1 to 3,
The volume changing means is
A first bellows and a second bellows having different inner dimensions are connected to each other, and a container for accommodating the tube member therein,
A link member fixed to the container and driven by the driving means at the driving speed;
With
An indirect liquid is enclosed in a space between the inner surface of the container and the outer surface of the tube member. A processing liquid supply for supplying a predetermined processing liquid stored in the tube member toward the slit nozzle by driving a volume changing means for changing the internal volume of the hollow tube member and reducing the internal volume. A method,
A starting step of starting driving the volume changing means;
A supply step of supplying the predetermined processing liquid so as to keep the discharge speed from the slit nozzle substantially constant by gradually reducing the drive speed of the volume changing means;
A stopping step of stopping driving of the volume changing means;
A process liquid supply method comprising: The processing liquid supply method according to claim 5,
An acceleration step of accelerating the drive speed to a temporary target speed by starting the start step;
A deceleration step of decelerating the drive speed to the target speed after the drive speed reaches the temporary target speed by the acceleration step;
The processing liquid supply method further comprising:

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