JP2006015308A - Apparatus for elevating/lowering coating nozzle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for elevating/lowering a coating nozzle, the responsiveness of which is improved by supplying rotational force to a ball nut for elevating/lowering the coating nozzle from a plurality of servomotors when the movement of the coating nozzle is started and stopped and in which overshoot is lessened when a position of the coating nozzle is controlled. <P>SOLUTION: A position controlling motor 1, a coupling 3, a pulley 8, a reduction gear 4 and another coupling 5 are arranged coaxially in this order from above in the upper part of a ball screw 6 and a torque controlling motor 2 is arranged on the lateral side of the position controlling motor 1. A rotary shaft 1A of the position controlling motor 1 and a rotary shaft 2A of the torque controlling motor 2 are connected to the single ball screw 6. The rotation of the position controlling motor 1 is transmitted to the ball screw 6 through the coupling 3, the reduction gear 4 and the coupling 5. The rotation of the torque controlling motor 2 is transmitted to the ball screw 6 through pulleys 8, 9, a belt 10, the reduction gear 4 and the coupling 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coating apparatus for forming a thin film such as a photoresist or a coating solution for a color filter, a developer or pure water on the surface of a flat substrate for a flat panel display, etc. The present invention relates to a coating nozzle lifting device that lifts and lowers.

  When a thin film is formed on the surface of a substrate by applying a liquid agent such as a photoresist or a color filter coating solution, a developing solution or pure water to the surface of a flat substrate for a flat panel display, etc. The interval affects the thickness of the thin film formed on the substrate surface. Therefore, in order to form a thin film with an appropriate film thickness on the substrate surface, the nozzle that discharges the liquid agent must be brought into contact with and separated from the substrate surface, and the distance between the nozzle and the substrate surface must be controlled with high accuracy. Don't be.

  For this reason, conventionally, in a coating apparatus used for manufacturing a substrate, a ball screw that is rotated by a servo motor is screwed to both ends in the longitudinal direction of the nozzle that is longer than one side of the substrate, and the nozzle is placed in the longitudinal direction above the substrate. The servo motor is driven based on the measurement result of the distance between the substrate and the nozzle while moving in a direction perpendicular to the nozzle. The ball screw is rotated by driving the servo motor, and the nozzles screwed to the ball screw are moved up and down at both ends.

  When the nozzle is raised and lowered by the rotation of the ball screw, the mass of the nozzle acts in the downward direction of the nozzle due to gravity. For this reason, the load on the servo motor is reduced when the nozzle is lowered, while the load on the servo motor is increased when the nozzle is raised, and the load acting on the servo motor differs significantly when the nozzle is lowered and raised. Thus, it becomes difficult to set parameters in the drive control of the servo motor, and there is a difference in response between when the nozzle is lowered and when it is raised.

Therefore, as a conventional coating apparatus, there is an apparatus provided with an air balancer that applies an upward thrust to the nozzle so that the load acting on the servo motor is constant when the nozzle is lowered and raised. This air balancer is generally used in a machine tool using a lifting mechanism using a ball screw (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 08-126907

  However, in the coating device equipped with an air balancer, the thrust in the upward direction is given to the nozzle by the expansion of the compressed air filled in the cylinder of the air balancer. Responsiveness cannot be obtained. For this reason, there is a problem that overshoot is likely to occur in nozzle position control, and it is difficult to accurately control the position of the nozzle with respect to the upper surface of the substrate, and a thin film having an appropriate film thickness cannot be formed on the substrate.

  The object of the present invention is to provide a ball nut for raising and lowering the nozzle by supplying rotational force from a plurality of servo motors, thereby providing excellent responsiveness in starting and stopping the nozzle raising and lowering operation, and overshooting in controlling the nozzle raising and lowering position An object of the present invention is to provide a coating nozzle lifting / lowering device that can be reduced and can form a thin film with an appropriate film thickness on a substrate.

  In order to solve the above problems, an application nozzle lifting device of the present invention has the following configuration.

  (1) A conversion transmission mechanism that converts a rotational motion into a linear motion in a direction in contact with and away from the top surface of the substrate to a nozzle that discharges the liquid agent on the top surface of the substrate, and a rotational force is supplied to the conversion transmission mechanism A plurality of servo motors, wherein at least one of the plurality of servo motors is a position control type motor that controls the vertical position of the nozzle with respect to the upper surface of the substrate, and the other acts on the position control type motor. A torque control type motor that adjusts the load is used.

  In this configuration, the rotation of the position control type motor and the torque control type motor, both of which are servo motors, is converted into a linear motion by the conversion transmission mechanism and transmitted to the nozzle, and the nozzle that discharges the liquid material onto the upper surface of the substrate Move toward or away. The position control type motor controls the vertical position of the nozzle with respect to the upper surface of the substrate, and the torque control type motor adjusts the load acting on the position control type motor.

  Therefore, the load acting on the position control type motor that rotates to move the nozzle closer to or away from the upper surface of the substrate so that the vertical position of the nozzle with respect to the upper surface of the substrate becomes appropriate is delayed by the rotation of the torque control type motor. It is adjusted accurately without accompanying.

  (2) The conversion transmission mechanism is constituted by a ball screw that is screwed into a part of a nozzle, and the rotation shaft of the position control type motor and the rotation shaft of the torque control type motor are connected to the single ball screw. And

  In this configuration, the rotation shaft of the position control type motor and the rotation shaft of the torque control type motor are connected to a single ball screw screwed into a part of the nozzle. Therefore, the load acting on the position control type motor that rotates to move the nozzle closer to or away from the upper surface of the substrate so that the position of the nozzle in the vertical direction with respect to the upper surface of the substrate is appropriate is torqued via a single ball screw. It is directly adjusted by the rotation of the control type motor.

  (3) The rotary shaft of the position control type motor and the rotary shaft of the torque control type motor are directly connected to the single ball screw in the axial direction.

  In this configuration, the rotation shaft of the position control type motor and the rotation shaft of the torque control type motor are directly connected in the axial direction to a single ball screw screwed into a part of the nozzle. Therefore, a transmission mechanism for transmitting the rotation of the position control type motor or the rotation of the torque control type motor to the ball screw is unnecessary so that the vertical position of the nozzle with respect to the upper surface of the substrate is appropriate.

  According to the coating nozzle lifting apparatus of the present invention, the following effects can be achieved.

  (1) The load acting on the position control type motor that rotates to move the nozzle closer to or away from the upper surface of the substrate so that the position of the nozzle in the vertical direction with respect to the upper surface of the substrate is appropriate. It can be adjusted accurately without any delay. As a result, the responsiveness of starting and stopping the raising / lowering operation of the nozzle can be improved, the overshoot in the control of the raising / lowering position of the nozzle can be reduced, and a thin film with an appropriate film thickness can be formed on the substrate.

  (2) A load acting on a position control type motor that rotates to move the nozzle closer to or away from the upper surface of the substrate so that the position of the nozzle in the vertical direction relative to the upper surface of the substrate becomes appropriate, via a single ball screw. It can be directly adjusted by the rotation of the torque control type motor. Thereby, the responsiveness of starting and stopping of the lifting operation of the nozzle can be further improved.

  (3) A transmission mechanism for transmitting the rotation of the position control type motor or the rotation of the torque control type motor to the ball screw is not required, and the response of starting and stopping the raising / lowering operation of the nozzle is improved with a very simple configuration. Can do.

  FIGS. 1A and 1B are a front view and a side view showing the configuration of the coating nozzle lifting apparatus according to the first embodiment of the present invention. The coating nozzle lifting apparatus D according to this embodiment constitutes a part of the coating apparatus E together with the stone surface plate B and the nozzle C. The coating apparatus E applies a photoresist, a color filter coating solution, a developer, pure water, or the like from the nozzle C to the upper surface of the substrate A placed on the stone surface plate B, and forms a thin film on the upper surface of the substrate A. Form. For this reason, the coating apparatus E moves the nozzle C longer than one side of the substrate A together with the application nozzle lifting apparatus D in the directions of arrows X and X ′ which are directions orthogonal to the longitudinal direction in the horizontal plane.

  The film thickness of the thin film to be formed on the upper surface of the substrate A may be partially different. Moreover, the case where there is an error in the height direction on the upper surface of the stone surface plate B or the case where there is an error in the thickness of the substrate A cannot be denied. The film thickness of the thin film formed on the upper surface of the substrate A is affected by the distance between the upper surface of the substrate A and the discharge port of the nozzle C. Therefore, in order to form a thin film with an appropriate film thickness on the upper surface of the substrate A, it is necessary to control the vertical position of the nozzle C with respect to the upper surface of the substrate A.

  For this reason, the nozzle C can be moved up and down in the vertical direction, which is the direction of the arrows Y and Y ′, by the coating nozzle lifting device D. The coating nozzle lifting device D is provided at both ends in the longitudinal direction of the nozzle C, but only one is shown in FIG. The coating nozzle lifting / lowering device D is provided with a ball screw 6 which is a conversion transmission mechanism of the present invention so as to be rotatable with its longitudinal direction vertical. The ball screw 6 is screwed into a fixing nut 12 fixed to both ends of the nozzle C via a support member 11. The ball screw 6 is screwed with the fixing nut 12 to convert the rotational motion into a linear motion in the vertical direction and transmit it to the nozzle C.

  Two guide rails 7 erected in the vertical direction pass through the support member 11. The support member 11 is guided by the guide rail 7 and moves only in the vertical direction.

  Above the ball screw 6, the position control type motor 1, the coupling 3, the pulley 8, the speed reducer 4, and the coupling 5 are arranged coaxially in order from the top. A torque control type motor 2 is disposed on the side of the position control type motor 1. A pulley 9 is fixed to the rotating shaft of the torque control type motor 2.

  The coupling 3 connects the rotary shaft 1A of the position control type motor 1 and the input shaft 4A of the speed reducer 4 to absorb the rotational difference between the two. The pulley 8 is fixed to the input shaft 4 </ b> A of the speed reducer 4. A timing belt 10 is stretched between the pulley 8 and the pulley 9. The pulley 8, the pulley 9, and the timing belt 10 correspond to the transmission mechanism of the present invention. The coupling 5 connects the output shaft 4B of the speed reducer 4 and the upper end of the ball screw 6 to absorb the rotational difference between them.

  Therefore, the rotary shaft 1A of the position control type motor 1 and the rotary shaft 2A of the torque control type motor 2 are connected to the single ball screw 6, and the rotation of the position control type motor 1 is coupled to the coupling 3 and the speed reducer 4. And transmitted to the ball screw 6 through the coupling 5. The rotation of the torque control type motor 2 is transmitted to the ball screw 6 through the pulleys 8 and 9 and the belt 10, the speed reducer 4, and the coupling 5.

  FIG. 2 is a block diagram illustrating a configuration of a control unit of the coating nozzle lifting device. The control unit 20 of the coating nozzle lifting device D includes a controller 21, a position control type servo driver 22, and a torque control type servo driver 23. The position control type servo driver 22 is directly connected to the controller 21, and the torque control type servo driver 23 is connected to the controller 21 via a changeover switch 24.

  Command position data is input from the controller 21 to the position control servo driver 22 and encoder pulses are input from a pulse encoder 25 provided in the position control motor 1. The position control type servo driver 22 drives the position control type motor 1 so that the number of encoder pulses output from the pulse encoder 25 matches the difference between the command position data and the current position data.

  The torque control type servo driver 23 is supplied with a rising voltage or a falling voltage from the analog output section of the controller 21 via the changeover switch 24. The controller 21 outputs a switching signal to the changeover switch 24 according to whether the nozzle C is raised or lowered, and supplies a voltage corresponding to the operation of the nozzle C to the torque control type servo driver 23. The torque control type servo driver 23 applies a drive voltage controlled so as to coincide with the rising voltage or falling voltage to the torque control motor 2.

  The rising voltage and falling voltage output from the controller 21 are determined based on loads acting on the position control type motor 1 via the ball nut 6 when the nozzle C is raised and lowered, respectively. The descending voltage is a voltage that slightly reduces the load acting on the position control type motor 1 when the nozzle C is lowered by the rotation of the torque control type motor 2. The rising voltage is a voltage that sufficiently reduces the load acting on the position control type motor 1 when the nozzle C is raised by the rotation of the torque control type motor 2. Thus, preferably, the load acting on the position control type motor 1 is matched when the nozzle C is raised and lowered.

  In this example, since the mass of the nozzle C is constant, the load acting on the position control type motor 1 when the nozzle C is raised and lowered is considered to be constant. Each voltage is uniquely determined. However, in order to make the load acting on the position control type motor 1 more strictly constant when the specific gravity differs remarkably depending on the type of liquid agent applied by the nozzle C, the load acting on the position control type motor 1 is set to be constant. It is also possible to measure and control the voltage applied to the torque control type motor 2 based on the measurement result.

With the above configuration, the load acting on the position control type motor 1 that rotates to move the nozzle C closer to or away from the upper surface of the substrate A so that the vertical position of the nozzle C relative to the upper surface of the substrate A becomes appropriate. Can be accurately adjusted without delay by the rotation of the torque control type motor 2. As a result, the responsiveness of starting and stopping the raising / lowering operation of the nozzle C can be improved, the overshoot in the control of the raising / lowering position of the nozzle C can be reduced, and a thin film with an appropriate film thickness can be formed on the substrate A. Further, the load acting on the position control type motor 1 can be directly adjusted by the rotation of the torque control type motor 2 via the single ball screw 6. Thereby, the responsiveness of starting and stopping of the raising / lowering operation of the nozzle C can be further improved.

  FIG. 3 is a side view showing the configuration of the coating nozzle lifting / lowering apparatus according to the second embodiment of the present invention. The application nozzle device D ′ according to this embodiment includes gears 31 and 32 instead of the pulleys 8 and 9 and the timing belt 10 of the application nozzle lifting device D shown in FIG. Other configurations are the same as those of the coating nozzle lifting device D.

  The coating nozzle elevating device D ′ has a gear 31 fixed to the input shaft 4 </ b> A of the speed reducer 4, and a gear 32 meshing with the gear 31 is fixed to the rotating shaft 2 </ b> A of the torque control type motor 2. Therefore, the rotation of the torque control type motor 2 is transmitted to the ball screw 6 through the gear 31, the gear 32, the speed reducer 4 and the coupling 5.

  FIG. 4 is a side view showing the configuration of the coating nozzle lifting apparatus according to the third embodiment of the present invention. The coating nozzle device D ″ according to this embodiment omits the pulleys 8 and 9 and the timing belt 10 of the coating nozzle lifting device D shown in FIG. 1, and controls the torque via the coupling 41 above the position control type motor 1. The mold motor 2 is arranged on the same axis, and the other configuration is the same as that of the coating nozzle lifting device D.

  The coupling 41 connects the rotation shaft 2A of the torque control type motor 2 and the rotation shaft 1A of the position control type motor 1 to absorb the rotation difference between the two. Therefore, the rotary shaft 1A of the position control type motor 1 and the rotary shaft 2A of the torque control type motor 2 are directly connected to the single ball screw 6, and the rotation of the torque control type motor 2 is transmitted via the coupling 41. The rotation of the position control type motor 1 is transmitted to the ball screw 6 through the coupling 3, the speed reducer 4 and the coupling 5.

  According to the configuration of the coating nozzle lifting device D ″ according to the third embodiment, a transmission mechanism for transmitting the rotation of the torque control type motor 2 to the ball screw 6 becomes unnecessary, and the lifting and lowering of the nozzle C with an extremely simple configuration. It is possible to improve the response of starting and stopping the operation.

It is the front view and side view which show the structure of the coating nozzle raising / lowering apparatus which concerns on 1st Embodiment of this invention. It is a block diagram which shows the structure of the control part of the said coating nozzle raising / lowering apparatus. It is a side view which shows the structure of the coating nozzle raising / lowering apparatus which concerns on 2nd Embodiment of this invention. It is a side view which shows the structure of the coating nozzle raising / lowering apparatus which concerns on 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Position control type motor 2 Torque control type motor 3 Coupling 4 Reduction gear 5 Coupling 6 Ball nut 7 Guide rail 8 Pulley 9 Pulley 10 Timing belt 11 Support member 12 Fixing nut A Substrate B Stone surface plate C Nozzle D Coating nozzle lifting / lowering Equipment E Coating equipment

Claims (3)

  A conversion transmission mechanism that converts rotational movement to a nozzle that discharges a liquid agent on the substrate upper surface into linear movement in a direction in contact with and away from the upper surface of the substrate, and a plurality of servo motors that supply rotational force to the conversion transmission mechanism And at least one of the plurality of servo motors is a position control type motor that controls the vertical position of the nozzle with respect to the upper surface of the substrate, and the other is used to adjust a load acting on the position control type motor. A coating nozzle lifting device characterized by being a torque control type motor. The conversion transmission mechanism is configured by a ball screw that is screwed into a part of a nozzle, and the rotation shaft of the position control type motor and the rotation shaft of the torque control type motor are connected to the single ball screw. Item 4. The coating nozzle lifting apparatus according to Item 1. The coating nozzle lifting / lowering device according to claim 2, wherein the rotation shaft of the position control type motor and the rotation shaft of the torque control type motor are directly connected to the single ball screw in the axial direction.

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