JP2018147977A - Floating amount calculation device, coating device, and coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely find a floating amount from a stage regardless of type of substrate in a coating device that applies coating liquid to the substrate while conveying the substrate in a state of floating over the stage.SOLUTION: A floating amount calculation device includes: a board thickness measuring sensor for detecting a vertical direction position of a suction face that sucks a lower face of a substrate of a sucking member, and a vertical direction position of an upper face region of a sucked portion sucked by the sucking member of the substrate; a floating measuring sensor for detecting a vertical direction position of an upper face of a stage and a vertical direction position of an upper face of the substrate transported upward of the stage; a board thickness calculation unit for calculating the board thickness of the substrate on the basis of the vertical direction position of the suction face and the vertical direction position of the upper face region of the sucked portion detected by the board thickness measuring sensor; and a floating amount calculation unit for calculating an amount of floating of the substrate on the basis of the vertical direction position of the upper face of the stage and the vertical direction position of the upper face of the substrate detected by the floating measuring sensor and the board thickness calculated by the board thickness calculation unit.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a coating apparatus and a coating method for applying a coating liquid onto an upper surface of a substrate while being transported in a horizontal direction in a state where the substrate is floated from a stage, and a flying height calculation apparatus for calculating a flying height in the coating apparatus. . The above substrates include semiconductor substrates, photomask substrates, liquid crystal display substrates, organic EL display substrates, plasma display substrates, FED (Field Emission Display) substrates, optical disk substrates, magnetic disk substrates, optical disks. Includes magnetic disk substrates.

  2. Description of the Related Art In manufacturing processes for electronic components such as semiconductor devices and liquid crystal display devices, a coating apparatus that discharges a coating liquid onto the upper surface of a substrate and applies it onto the upper surface of the substrate is used. For example, in the coating apparatus described in Patent Document 1, the gas is blown onto the lower surface of the substrate and the substrate is transported from the stage while the substrate is lifted from the stage. The coating liquid is applied to almost the entire surface of the substrate by discharging from the outlet onto the surface of the substrate.

Japanese Patent No. 5346663

  In the apparatus described in Patent Document 1, an optical sensor for detecting the flying height of the substrate in a non-contact manner with respect to the slit nozzle is installed. The position of the slit nozzle in the vertical direction (hereinafter referred to as “vertical position”) is adjusted based on the detection result of the optical sensor. Here, when the substrate is made of a transparent material, three types of vertical positions (a vertical position on the upper surface of the floating substrate, a vertical position on the lower surface of the substrate, and a vertical position on the upper surface of the stage are detected by the sensor. Direction position) can be detected, and the thickness of the substrate and the flying height from the stage can be calculated based on these vertical positions.

  However, it is difficult to detect the vertical position of the lower surface of the substrate with a substrate containing a light-shielding material, such as a metal-deposited substrate. Therefore, in the above apparatus, the coating process is performed on the premise that the substrate is floating with a flying amount corresponding to the gas blowing state on the lower surface of the substrate, for example, the gas flow rate. Therefore, for example, if the flying height is small or becomes zero due to fluctuations in the gas flow rate, the substrate cannot be transported satisfactorily, and as a result, the accuracy of the coating process may be reduced. As described above, a fixed value may be used as described above even though the flying height is an important physical quantity for performing a high-precision coating process satisfactorily. Therefore, conventionally, in a coating technique for performing a coating process while a substrate is levitated, there is a demand for a technique for accurately obtaining the flying height regardless of the type of the substrate.

  The present invention has been made in view of the above problems, and in a coating apparatus that applies a coating liquid to a substrate while transporting the substrate while floating from the stage, the flying height from the stage is highly accurate regardless of the type of the substrate. The purpose is to provide the technology that can be sought.

  In the first aspect of the present invention, the lower surface is partially held by the adsorbing member of the transport unit and is transported to the stage by the transport unit. In the coating apparatus for applying the coating liquid by discharging the coating liquid from the nozzle to the substrate, the flying height calculating device for calculating the flying height of the substrate from the stage, and the vertical position of the suction surface that sucks the lower surface of the substrate among the suction members A plate thickness measurement sensor for detecting the vertical position of the upper surface area of the portion to be adsorbed adsorbed by the adsorbing member of the substrate, the vertical position of the upper surface of the stage, and the position of the substrate conveyed above the stage Sensor for measuring the vertical position of the upper surface, the vertical position of the suction surface detected by the sensor for thickness measurement, and the vertical direction of the upper surface area of the attracted part The thickness calculation unit for calculating the thickness of the substrate based on the position, the vertical position of the upper surface of the stage and the vertical position of the upper surface of the substrate detected by the levitation measurement sensor, and the thickness calculation unit And a flying height calculation unit that calculates the flying height of the substrate based on the plate thickness.

  According to a second aspect of the present invention, there is provided a coating apparatus including a suction member that partially holds and holds the lower surface of the substrate, and transports the substrate in a predetermined transport direction while holding the substrate by the suction member. A substrate, a stage that floats the substrate by applying buoyancy to the substrate conveyed by the conveyance unit, a nozzle that discharges and applies a coating liquid onto the substrate that is levitated from the stage, and a lower surface of the substrate among the adsorption members A plate thickness measurement sensor for detecting the vertical position of the suction surface to be sucked and the vertical position of the upper surface region of the portion to be sucked which is sucked by the suction member of the substrate, the vertical position of the upper surface of the stage, and the stage Sensor for detecting the vertical position of the upper surface of the substrate transported above the substrate, and the vertical position of the suction surface and the vertical position of the upper surface area of the portion to be sucked detected by the sensor for thickness measurement A plate thickness calculation unit for calculating the plate thickness of the substrate based on the above, a vertical position of the upper surface of the stage detected by the sensor for levitation measurement, a vertical position of the upper surface of the substrate, and a plate calculated by the plate thickness calculation unit And a flying height calculation unit that calculates the flying height of the substrate based on the thickness.

  Further, according to the third aspect of the present invention, while the lower surface is partially held by the suction member of the transport unit, the transport unit transports the substrate to the stage and applies buoyancy from below to the substrate to lift the substrate upward from the stage. A coating method in which a coating liquid is ejected from a nozzle onto a floating substrate and applied, and before the coating liquid is applied to the substrate, the vertical position of the suction surface that sucks the lower surface of the substrate among the suction members and the stage A first step of detecting the vertical position of the upper surface, a second step of detecting the vertical position of the upper surface region of the portion to be adsorbed by the adsorption member after the substrate is held by the adsorption member, and adsorption A third step of calculating the thickness of the substrate based on the vertical position of the surface and the vertical position of the upper surface area of the attracted part, and transported above the stage by the transport unit while being held by the suction member The amount of floating of the substrate based on the fourth step of detecting the vertical position of the upper surface of the substrate, the vertical position of the upper surface of the stage, the vertical position of the upper surface of the substrate, and the plate thickness calculated in the fourth step And a fifth step of calculating.

  In the invention configured as described above, a part of the lower surface of the substrate (the lower surface of the attracted part) is adsorbed by the adsorption member of the conveyance unit and is held by the conveyance unit. Among them, it coincides with the vertical position of the suction surface that sucks the lower surface of the substrate. Therefore, the vertical position of the lower surface of the attracted portion is substantially detected by detecting the vertical position of the attracting surface before the substrate is held by the attracting member. Then, by detecting the vertical position of the upper surface region of the attracted part after holding the substrate, the vertical positions of the upper surface and the lower surface of the substrate are aligned, and the thickness of the substrate can be accurately calculated. On the other hand, when the vertical position of the upper surface of the stage is detected before transporting the substrate and the vertical position of the upper surface of the substrate transported above the stage is detected, the vertical position and the thickness of the substrate are determined. Based on this, the flying height of the substrate is calculated with high accuracy.

  As described above, according to the present invention, the thickness of the substrate is calculated based on the vertical position of the suction surface that sucks the lower surface of the substrate and the vertical position of the upper surface area of the attracted portion. Since the flying height of the substrate is calculated based on the vertical position of the upper surface of the stage and the vertical position of the upper surface of the substrate, the flying height from the stage can be obtained with high accuracy.

It is a figure which shows typically the whole structure of the coating device equipped with one Embodiment of the flying height calculation apparatus concerning this invention. It is the top view which looked at the coating device from the perpendicular upper direction. It is the top view which removed the application | coating mechanism from FIG. It is the sectional view on the AA line of FIG. It is a flowchart which shows the flow of the flying height calculation process by this coating device, and the flow of a coating process. It is a figure which shows typically the positional relationship of each part in a process.

  FIG. 1 is a diagram schematically showing the overall configuration of a coating apparatus equipped with an embodiment of a flying height calculation apparatus according to the present invention. The coating apparatus 1 is a slit coater that applies a coating solution to the upper surface Wf of the substrate W that is transported in a horizontal posture from the left hand side to the right hand side in FIG. In the following drawings, in order to clarify the arrangement relationship of each part of the apparatus, the transport direction of the substrate W is referred to as “X direction”, and the horizontal direction from the left hand side to the right hand side in FIG. 1 is referred to as “+ X direction”. The reverse direction is referred to as the “−X direction”. Further, among the horizontal direction Y orthogonal to the X direction, the front side of the apparatus is referred to as “−Y direction” and the back side of the apparatus is referred to as “+ Y direction”. Further, the upward direction and the downward direction in the vertical direction Z are referred to as “+ Z direction” and “−Z direction”, respectively.

  First, the outline of the configuration and operation of the coating apparatus 1 will be described with reference to FIG. 1, and then the detailed structure of each part will be described. Note that the basic configuration and operation principle of the coating apparatus 1 are the same as those described in Japanese Patent No. 5346663 (Patent Document 1) previously disclosed by the applicant of the present application. Therefore, in the present specification, among the configurations of the coating apparatus 1, configurations similar to those described in these known documents can be applied, and structures can be easily understood from the descriptions of these documents. Detailed description will be omitted, and the characteristic part of this embodiment will be mainly described.

  In the coating apparatus 1, the input conveyor 100, the input transfer unit 2, the floating stage unit 3, the output transfer unit 4, and the output conveyor 110 are arranged close to each other in this order along the transport direction Dt (+ X direction) of the substrate W. Thus, as will be described in detail below, a transport path for the substrate W extending in a substantially horizontal direction is formed. In the following description, when the positional relationship is shown in association with the transport direction Dt of the substrate W, “upstream side in the transport direction Dt of the substrate W” is simply referred to as “upstream side”, and “downstream in the transport direction Dt of the substrate W”. "Side" may be simply abbreviated as "Downstream". In this example, the (−X) side relatively corresponds to “upstream side” and the (+ X) side corresponds to “downstream side” when viewed from a certain reference position.

  The substrate W to be processed is carried into the input conveyor 100 from the left hand side of FIG. The input conveyor 100 includes a roller conveyor 101 and a rotation driving mechanism 102 that rotationally drives the roller conveyor 101, and the substrate W is transported in a horizontal posture downstream, that is, in the (+ X) direction by the rotation of the roller conveyor 101. The input transfer unit 2 includes a roller conveyor 21 and a rotation / elevation drive mechanism 22 having a function of rotationally driving the roller conveyor 21 and a function of elevating and lowering the roller conveyor 21. As the roller conveyor 21 rotates, the substrate W is further transported in the (+ X) direction. Moreover, the vertical direction position of the board | substrate W is changed because the roller conveyor 21 raises / lowers. The substrate W is transferred from the input conveyor 100 to the floating stage unit 3 by the input transfer unit 2 configured as described above.

  The levitation stage unit 3 includes a flat stage divided into three along the substrate transport direction Dt. That is, the levitation stage unit 3 includes an inlet levitation stage 31, a coating stage 32, and an outlet levitation stage 33, and the upper surfaces of these stages are part of the same plane. The upper surfaces of the inlet levitation stage 31 and the outlet levitation stage 33 are provided with a large number of ejection holes for ejecting compressed air supplied from the levitation control mechanism 35 in a matrix, and the buoyancy imparted from the ejected airflow The substrate W rises. Thus, the lower surface Wb of the substrate W is supported in a horizontal posture in a state of being separated from the upper surface of the stage. The distance between the lower surface Wb of the substrate W and the upper surface of the stage, that is, the flying height can be, for example, 10 micrometers to 500 micrometers.

  On the other hand, on the upper surface of the coating stage 32, ejection holes for ejecting compressed air and suction holes for sucking air between the lower surface Wb of the substrate W and the upper surface of the stage are alternately arranged. The distance between the lower surface Wb of the substrate W and the upper surface of the coating stage 32 is precisely controlled by the levitation control mechanism 35 controlling the amount of compressed air ejected from the ejection holes and the amount of suction from the suction holes. Thereby, the vertical position of the upper surface Wf of the substrate W passing over the coating stage 32 is controlled to a specified value. As a specific configuration of the levitation stage unit 3, for example, the one described in Japanese Patent No. 5346663 (Patent Document 1) can be applied. The flying height on the coating stage 32 is calculated by the control unit 9 based on detection results by sensors 61 and 62, which will be described in detail later, and can be adjusted with high accuracy by airflow control.

  The entrance levitation stage 31 is provided with lift pins not shown in the drawing, and the levitation stage portion 3 is provided with a lift pin drive mechanism 34 for raising and lowering the lift pins.

  The substrate W carried into the levitation stage unit 3 via the input transfer unit 2 is given a propulsive force in the (+ X) direction by the rotation of the roller conveyor 21 and is conveyed onto the inlet levitation stage 31. The inlet floating stage 31, the coating stage 32, and the outlet floating stage 33 support the substrate W in a floating state, but do not have a function of moving the substrate W in the horizontal direction. The transport of the substrate W in the levitation stage unit 3 is performed by the substrate transport unit 5 disposed below the entrance levitation stage 31, the coating stage 32, and the exit levitation stage 33.

  The substrate transport unit 5 includes a chuck mechanism 51 that supports the substrate W from below by partially abutting on the peripheral edge of the lower surface of the substrate W, and an adsorption member (see FIGS. 3, 4, and 6). A suction / running control mechanism 52 having a function of sucking and holding the substrate W by sucking a suction pad (not shown) provided in the reference numeral 513) and a function of reciprocating the chuck mechanism 51 in the X direction. I have. In a state where the chuck mechanism 51 holds the substrate W, the lower surface Wb of the substrate W is positioned higher than the upper surface of each stage of the levitation stage unit 3. Therefore, the substrate W maintains the horizontal posture as a whole by the buoyancy applied from the levitation stage unit 3 while the peripheral portion is sucked and held by the chuck mechanism 51. A plate thickness measuring sensor 61 is disposed in the vicinity of the roller conveyor 21 in order to detect the vertical position of the upper surface of the substrate W when the lower surface Wb of the substrate W is partially held by the chuck mechanism 51. . By positioning the chuck (see reference numeral 51R in FIGS. 3, 4, and 6 later) in a state where the substrate W is not held immediately below the sensor 61, the sensor 61 is positioned on the upper surface of the suction member, that is, the suction. The vertical position of the surface (see reference numeral 513a in FIG. 6) can be detected.

  The chuck mechanism 51 holds the substrate W carried into the floating stage unit 3 from the input transfer unit 2, and the substrate W moves above the entrance floating stage 31 by moving the chuck mechanism 51 in the (+ X) direction in this state. From above the coating stage 32 and then conveyed above the outlet floating stage 33. The transported substrate W is transferred to the output transfer unit 4 disposed on the (+ X) side of the outlet floating stage 33.

  The output transfer unit 4 includes a roller conveyor 41, and a rotation / lift drive mechanism 42 having a function of rotating and driving the roller conveyor 41. By rotating the roller conveyor 41, a propulsive force in the (+ X) direction is applied to the substrate W, and the substrate W is further transported along the transport direction Dt. Further, the vertical position of the substrate W is changed by moving the roller conveyor 41 up and down. The operation realized by raising and lowering the roller conveyor 41 will be described later. The substrate W is transferred to the output conveyor 110 from above the outlet floating stage 33 by the output transfer unit 4.

  The output conveyor 110 includes a roller conveyor 111 and a rotation driving mechanism 112 that rotates and drives the substrate. The substrate W is further transported in the (+ X) direction by the rotation of the roller conveyor 111, and finally the outside of the coating apparatus 1. To be paid out. The input conveyor 100 and the output conveyor 110 may be provided as part of the configuration of the coating apparatus 1, but may be separate from the coating apparatus 1. Further, for example, a separate unit substrate dispensing mechanism provided on the upstream side of the coating apparatus 1 may be used as the input conveyor 100. Further, a substrate receiving mechanism of another unit provided on the downstream side of the coating apparatus 1 may be used as the output conveyor 110.

  A coating mechanism 7 for coating the coating liquid on the upper surface Wf of the substrate W is disposed on the transport path of the substrate W transported in this manner. The coating mechanism 7 includes a nozzle 71 that is a slit nozzle and a maintenance unit 75 for performing maintenance on the nozzle 71. A coating liquid is supplied to the nozzle 71 from a coating liquid supply unit (not shown), and the coating liquid is discharged from a discharge port that opens downward in the lower part of the nozzle.

  The nozzle 71 can be moved and positioned in the X direction and the Z direction by a positioning mechanism 73. The positioning mechanism 73 positions the nozzle 71 at a coating position (position indicated by a dotted line) above the coating stage 32. The coating liquid is discharged from the nozzle positioned at the coating position, and is applied to the substrate W transported between the coating stage 32. Thus, the coating liquid is applied to the substrate W. As will be described later in detail, the nozzle 71 has a levitation measurement sensor 62 that detects the vertical position of the upper surface of the coating stage 32 and the vertical position of the upper surface of the substrate W in order to measure the flying height. It is attached.

  The maintenance unit 75 includes a bat 751 that stores cleaning liquid for cleaning the nozzle 71, a preliminary discharge roller 752, a nozzle cleaner 753, and a maintenance control mechanism 754 that controls operations of the preliminary discharge roller 752 and the nozzle cleaner 753. I have. As a specific configuration of the maintenance unit 75, for example, a configuration described in JP 2010-240550 A can be applied.

  At the position where the nozzle 71 is above the preliminary discharge roller 752 and the discharge port faces the upper surface of the preliminary discharge roller 752 (preliminary discharge position), the coating liquid is discharged from the discharge port of the nozzle 71 toward the upper surface of the preliminary discharge roller 752. The The nozzle 71 is positioned at the preliminary discharge position prior to being positioned at the application position, and performs a preliminary discharge process by discharging a predetermined amount of coating liquid from the discharge port. Thus, by causing the nozzle 71 before moving to the application position to perform the preliminary discharge process, the discharge of the coating liquid at the application position can be stabilized from the initial stage.

  The maintenance control mechanism 754 rotates the preliminary discharge roller 752 so that the discharged coating liquid is mixed with the cleaning liquid stored in the bat 751 and collected. Further, in a state where the nozzle 71 is located above the nozzle cleaner 753 (first cleaning position), the nozzle cleaner 753 moves in the Y direction while discharging the cleaning liquid, thereby adhering to the discharge port of the nozzle 71 and its surroundings. The coating solution is washed away.

  Further, the positioning mechanism 73 can position the nozzle 71 at a position (standby position) below the first cleaning position and where the lower end of the nozzle is accommodated in the bat 751. When the coating process using the nozzle 71 is not executed, the nozzle 71 is positioned at this standby position. Although illustration is omitted, a standby pod for preventing the coating liquid from drying at the discharge port may be arranged for the nozzle 71 positioned at the standby position.

  In addition, the coating apparatus 1 is provided with a control unit 9 for controlling the operation of each part of the apparatus. The control unit 9 includes a storage unit 91 that stores a predetermined control program and various data, an arithmetic unit 92 such as a CPU that executes each control unit by executing this control program, and exchanges information with a user or an external device. Is provided with interface means 93 and the like. In the present embodiment, as will be described later, the calculation unit 92 calculates the plate thickness and the flying height of the substrate W based on the detection results of the sensors 61 and 62, and functions as the plate thickness calculation unit 921 and the flying height calculation unit 922.

  FIG. 2 is a plan view of the coating apparatus as viewed from above. FIG. 3 is a plan view in which the coating mechanism is removed from FIG. 4 is a cross-sectional view taken along line AA in FIG. Hereinafter, a specific mechanical configuration of the coating apparatus 1 will be described with reference to these drawings. With regard to some mechanisms, a more detailed structure can be understood by referring to the description of Japanese Patent No. 5346663 (Patent Document 1). In FIGS. 2 and 3, the description of the rollers of the input conveyor 100 and the like is omitted.

  The nozzle unit 70 of the coating mechanism 7 has a bridging structure as shown in FIGS. Specifically, the nozzle unit 70 is composed of a pair of column members 732 and 733 erected upward from the base 10 at both ends in the Y direction of the beam member 731 extending in the Y direction above the floating stage unit 3. It has a supported structure. An elevating mechanism 734 configured by, for example, a ball screw mechanism is attached to the column member 732, and the (+ Y) side end portion of the beam member 731 is supported by the elevating mechanism 734 so as to be movable up and down. Further, an elevating mechanism 735 configured by, for example, a ball screw mechanism is attached to the column member 733, and the (−Y) side end portion of the beam member 731 is supported by the elevating mechanism 735 so as to be movable up and down. The elevating mechanisms 734 and 735 are interlocked according to a control command from the control unit 9, so that the beam member 731 moves in the vertical direction (Z direction) while maintaining a horizontal posture.

  A nozzle 71 is attached to the lower center of the beam member 731 with the discharge port 711 facing downward. Therefore, movement of the nozzle 71 in the Z direction is realized by operating the lifting mechanisms 734 and 735.

  The column members 732 and 733 are configured to be movable in the X direction on the base 10. Specifically, a pair of travel guides 81 </ b> L and 81 </ b> R extending in the X direction are attached to the upper surfaces of the (+ Y) side and (−Y) side end portions of the base 10, and the column member 732. Is engaged with the traveling guide 81L on the (+ Y) side through a slider 736 attached to the lower part thereof. The slider 736 is movable in the X direction along the traveling guide 81L. Similarly, the column member 733 is engaged with the travel guide 81R on the (−Y) side via a slider 737 attached to the lower portion thereof, and is movable in the X direction.

  The column members 732 and 733 are moved in the X direction by the linear motors 82L and 82R. Specifically, the magnet modules of the linear motors 82L and 82R are extended along the X direction on the base 10 as stators, and the coil modules are attached to the lower portions of the column members 732 and 733 as movers. When the linear motors 82L and 82R are operated in accordance with a control command from the control unit 9, the entire nozzle unit 70 moves along the X direction. Thereby, the movement of the nozzle 71 in the X direction is realized. The X-direction positions of the column members 732 and 733 can be detected by linear scales 83L and 83R provided in the vicinity of the sliders 736 and 737.

  Thus, the nozzle 71 moves in the Z direction by operating the elevating mechanisms 734 and 735, and the nozzle 71 moves in the X direction by operating the linear motors 82L and 82R. That is, when the control unit 9 controls these mechanisms, the nozzle 71 is positioned at each stop position (application position, preliminary discharge position, etc.). Accordingly, the elevating mechanisms 734 and 735, the linear motors 82L and 82R, the control unit 9 for controlling these, and the like function as the positioning mechanism 73 in FIG.

  The maintenance unit 75 has a structure in which a preliminary discharge roller 752 and a nozzle cleaner 753 are accommodated in a butt 751. Although not shown, the maintenance unit 75 is provided with a maintenance control mechanism 754 for driving the preliminary discharge roller 752 and the nozzle cleaner 753. The bat 751 is supported by a beam member 761 extending in the Y direction, and both ends of the beam member 761 are supported by a pair of column members 762 and 763. The pair of column members 762 and 763 are attached to both ends of the plate 764 extending in the Y direction in the Y direction.

  A pair of travel guides 84 </ b> L and 84 </ b> R extend in the X direction on the base 10 below both ends in the Y direction of the plate 764. Both ends of the plate 764 in the Y direction are engaged with the travel guides 84L and 84R via sliders 766 and 767, respectively. For this reason, the maintenance unit 75 is movable in the X direction along the travel guides 84L and 84R. A linear motor 85 is provided below the (−Y) direction end of the plate 764. The linear motor 85 may be provided below the (+ Y) direction end of the plate 764, or may be provided below the both ends of the Y direction.

  In the linear motor 85, a magnet module is extended as a stator on the base 10 along the X direction, and a coil module is attached to the maintenance unit 75 as a mover. By operating the linear motor 85 according to a control command from the control unit 9, the entire maintenance unit 75 moves along the X direction. The position of the maintenance unit 75 in the X direction can be detected by a linear scale 86 provided in the vicinity of the sliders 766 and 767.

  Next, the structure of the chuck mechanism 51 will be described with reference to FIGS. The chuck mechanism 51 includes a pair of chucks 51L and 51R that have a symmetrical shape with respect to the XZ plane and are spaced apart in the Y direction. Of these, the chuck 51L disposed on the (+ Y) side is supported by the traveling guide 87L extending in the X direction on the base 10 so as to be able to travel in the X direction. Specifically, the chuck 51L includes a base portion 512 having two horizontal plate portions provided at different positions in the X direction and a connection portion that connects these plate portions. Sliders 511 are respectively provided below the two plate portions of the base portion 512, and the base portion 512 can travel in the X direction along the travel guide 87L by engaging the slider 511 with the travel guide 87L. ing.

  At the upper part of the two plate parts of the base part 512, suction members 513 and 513 are provided that are provided with suction pads (not shown) extending upward and not shown. When the base portion 512 moves in the X direction along the travel guide 87L, the two adsorbing members 513 and 513 move in the X direction integrally therewith. The two plate portions of the base portion 512 may be separated from each other, and the plate portions may be structured to function as an integral base portion by moving while maintaining a certain distance in the X direction. If this distance is set according to the length of the substrate, it is possible to deal with substrates of various lengths.

  The chuck 51L is movable in the X direction by a linear motor 88L. That is, the magnet module of the linear motor 88L is extended as a stator on the base 10 in the X direction, and the coil module is attached as a mover to the lower part of the chuck 51L. The linear motor 88L is actuated in accordance with a control command from the control unit 9, whereby the chuck 51L moves along the X direction. The position of the chuck 51L in the X direction can be detected by the linear scale 89L.

  Similarly, the chuck 51 </ b> R provided on the (−Y) side includes a base portion 512 having two plate portions and a connection portion, and suction members 513 and 513. However, the shape is symmetrical to the chuck 51L with respect to the XZ plane. Each plate portion is engaged with the travel guide 87R by a slider 511. Further, the chuck 51R is movable in the X direction by a linear motor 88R. That is, the magnet module of the linear motor 88R is extended as a stator on the base 10 in the X direction, and the coil module is attached as a mover to the lower part of the chuck 51R. The linear motor 88R is actuated according to a control command from the control unit 9, whereby the chuck 51R moves along the X direction. The X-direction position of the chuck 51R can be detected by the linear scale 89R.

  The control unit 9 controls these positions so that the chucks 51L and 51R are always at the same position in the X direction. As a result, the pair of chucks 51L and 51R apparently move as an integrated chuck mechanism 51. Compared with the case where the chucks 51L and 51R are mechanically coupled, interference between the chuck mechanism 51 and the floating stage unit 3 can be easily avoided.

  As shown in FIG. 3, the four adsorption members 513 are arranged corresponding to the four corners of the substrate W to be held. That is, the two suction members 513 and 513 of the chuck 51L hold the upstream end and the downstream end in the transport direction Dt, respectively, on the (+ Y) side periphery of the substrate W. On the other hand, the two adsorbing members 513 and 513 of the chuck 51R respectively hold the upstream end and the downstream end in the transport direction Dt on the (−Y) side periphery of the substrate W. A negative pressure is supplied to the suction pads of each suction member 513 as necessary, whereby the four corners of the substrate W are sucked and held by the chuck mechanism 51 from below.

  The substrate W is transported by the chuck mechanism 51 moving in the X direction while holding the substrate W. Thus, the linear motors 88L and 88R, a mechanism (not shown) for supplying negative pressure to each suction member 513, the control unit 9 for controlling these, and the like are integrated into the suction / travel control mechanism 52 of FIG. Is functioning as

  As shown in FIGS. 1 and 4, the chuck mechanism 51 holds the lower surface Wb of the substrate W above the upper surfaces of the stages of the floating stage unit 3, that is, the inlet floating stage 31, the coating stage 32, and the outlet floating stage 33. In this state, the substrate W is transferred. Since the chuck mechanism 51 only holds a part of the outer peripheral edge in the Y direction with respect to the central portion of the substrate W facing the stages 31, 32, 33, the central portion of the substrate W is at the peripheral portion. On the other hand, it will bend downward. The levitation stage unit 3 has a function of controlling the vertical position of the substrate W to maintain a horizontal posture by applying buoyancy to the central portion of the substrate W.

  Among the stages of the levitation stage unit 3, the exit levitation stage 33 has a lower position where the upper surface position is lower than the upper surface position of the chuck mechanism 51, and an upper position where the upper surface position is higher than the upper surface position of the chuck mechanism 51. Can be moved up and down. For this purpose, the outlet levitation stage 33 is supported by a lift drive mechanism 36.

  Next, the flying height calculation process and the coating process in the coating apparatus configured as described above will be described with reference to FIGS. 5 and 6. FIG. 5 is a flowchart showing the flow of the flying height calculation process and the coating process in this coating apparatus. FIG. 6 is a diagram schematically showing the positional relationship between the respective parts in the flying height calculation process, and the positional relationship among the chuck mechanism 51, the nozzle 71 and the substrate W in the flying height calculation process is schematically shown in the central area of FIG. In the left area, the positional relationship between the chuck mechanism 51 and the substrate W at a position immediately below the sensor 61 is shown enlarged, and in the right area, the sensor 62 when the nozzle 71 is positioned at the application position is shown. The positional relationship between the nozzle 71 and the substrate W at the position immediately below is shown enlarged. Based on the detection results by these sensors 61 and 62, the flying height calculation is executed as one operation during the coating process.

  In the coating apparatus 1, the thickness of the substrate W and the flying height of the substrate W from the coating stage 32 are calculated during the coating process, and the vertical position of the suction surface and the upper surface of the coating stage 32 are calculated. Information on the vertical position of the image (hereinafter referred to as “reference information”) is required. Although the reference information is not necessary for the coating process for each substrate, it is necessary to acquire an appropriate timing and store it in the storage unit 91. Therefore, in the present embodiment, the calculation means 92 controls each part of the apparatus as follows in accordance with a control program stored in advance in the storage means 91 to appropriately acquire the reference information and be conveyed by the input conveyor 100. The coating process is performed on the substrate W while measuring the thickness and the flying height of the substrate W.

  In this embodiment, it is determined whether or not it is time to acquire reference information in step S1. Examples of triggers for setting the timing include power-on, completion of maintenance, reaching the predetermined value of the cumulative number of substrates W that have been subjected to coating processing, or instructions from the user via an operation panel (not shown). It is. It should be noted that at the stage of executing Step S1, the application process is not performed, and the nozzle 71 is positioned at the standby position, and the discharge of the application liquid is stopped. Further, the substrate W is not present in the input transfer unit 2, the floating stage unit 3, and the output conveyor 110. Further, the chuck mechanism 51 is retracted in the (+ X) direction from the transfer start position (the position immediately below the substrate W sent to the floating stage unit 3 by the input transfer unit 2 as shown in the column (b) of FIG. 6). Is positioned.

  When it is determined in step S1 that the acquisition of the reference information is unnecessary (NO in step S1), the process proceeds to step S8 without executing the reference information acquisition process (steps S2 to S7). On the other hand, when it is determined that the acquisition of the reference information is necessary (YES in step S1), the process proceeds to step S8 after executing steps S2 to S7 described below.

  In step S2, the moving positioning of the nozzle 71 from the standby position to the application position is performed. As a result, the levitation measurement sensor 62 attached to the nozzle 71 is positioned immediately above the upper surface of the coating stage 32. At this stage, as shown in the column (a) of FIG. 6, the substrate W does not exist immediately below the nozzle 71, and the upper surface (hereinafter referred to as “stage upper surface”) 321 of the coating stage 32 is the detection surface of the sensor 62. Directly opposite. A light projector (not shown) and a light receiver (not shown) are provided on the detection surface of the sensor 62. Light is emitted from the light projecting unit, and light reflected by the suction surface 513a is received by the light receiving unit. The light is received, and the vertical position of the stage upper surface 321 is acquired (step S3). The sensor 61 is the same in that the sensor has a projector and a light receiver.

  A signal indicating the vertical position is output from the sensor 62 to the control unit 9, and vertical position data of the stage upper surface 321 is stored in the storage unit 91. After the vertical position of the stage upper surface 321 is acquired, the nozzle 71 is moved to the standby position (step S4). In the present embodiment, the detection surface of the levitation measurement sensor 62 in step S2 and the detection surface of the plate thickness measurement sensor 61 described below are set to the same height in the vertical direction Z. Thus, the distance from each detection surface corresponds to the vertical position, and for example, the vertical position of the stage upper surface 321 is the distance Lb.

  At the same time as or before or after the step of acquiring the vertical position of the stage upper surface 321 (steps S2 to S4), the step of acquiring the vertical position of the suction surface 513a (steps S5 to S7) is executed. That is, in step S5, the chuck mechanism 51 moves in the (−X) direction and moves to the conveyance start position. As a result, in the chuck mechanism 51, the chuck 51R on the (−X) direction side is positioned immediately below the sensor 61 for measuring the plate thickness. Also at this stage, as shown in the column (a) of FIG. 6, the substrate W does not exist above the chuck mechanism 51, and the upper surface of the chucking member 513 of the chuck 51 </ b> R, that is, the chucking surface 513 a is the sensor 61. Directly facing the detection surface. In the sensor 61, light is emitted from the light projecting unit, and the light reflected by the suction surface 513a is received by the light receiving unit, and the distance Lv from the detection surface to the suction surface 513a is acquired as the vertical position of the suction surface 513a. (Step S6). A signal indicating the vertical position is output from the sensor 61 to the control unit 9, and the vertical position data of the suction surface 513 a is stored in the storage unit 91. After acquiring the vertical position of the suction surface 513a, the chuck mechanism 51 retracts in the (+ X) direction from the transfer start position. When the vertical position (Lb) of the stage upper surface 321 and the vertical position (distance Lv) of the suction surface 513a are obtained as reference information for calculating the flying height, the process proceeds to step S8.

  In step S8, the nozzle 71 used for the coating process is moved to the preliminary discharge position to execute the preliminary discharge process. Moreover, the jet of compressed air in the levitation stage unit 3 is started, and preparation is made so that the substrate W to be carried in can be levitated. The nozzle 71 discharges a predetermined amount of the coating liquid toward the preliminary discharge roller 752 at the preliminary discharge position, so that the discharge amount of the coating liquid from the nozzle 71 can be stabilized. In addition, the cleaning process of the nozzle 71 may be performed prior to the preliminary discharge process.

  Next, the carrying-in of the substrate W to the coating apparatus 1 is started (step S9). A substrate W to be processed is placed on the input conveyor 100 by another upstream processing unit, a transport robot, and the like, and the roller conveyor 101 rotates to transport the substrate W in the (+ X) direction. At this time, the nozzle 71 performs the preliminary discharge process at the preliminary discharge position. Further, the chuck mechanism 51 is retracted and positioned downstream of the inlet levitation stage 31.

  When the input conveyor 100 and the input transfer unit 2 in which the upper surface of the roller conveyor 21 is positioned at the same height as the roller conveyor 101 of the input conveyor 100 cooperate with each other, the substrate W is ejected by compressed air. It is transported to the upper part of the entrance levitation stage 31 that gives buoyancy to the surface. At this time, the upper surface of the entrance levitation stage 31 is lower than the upper surface of the roller conveyor 21, and the substrate W is in a state where the upstream end (the rear end in the moving direction) rides on the roller conveyor 21. Therefore, the substrate W does not slide on the entrance levitation stage 31.

  When the substrate W is thus carried into the entrance levitation stage 31, the lift pins provided on the entrance levitation stage 31 are positioned by the lift pin drive mechanism 34 at an upper position where the upper end protrudes above the upper surface of the entrance levitation stage 31. . As a result, both ends in the Y direction of the substrate W, more specifically, the substrate W with which the lift pins abut are lifted.

  Then, the chuck mechanism 51 moves in the (−X) direction and moves to the transfer start position directly below the substrate W (step S10). Since both ends in the Y direction of the substrate W are lifted by the lift pins 311, it is possible to avoid the chuck mechanism 51 entering the lower side of the substrate W from coming into contact with the substrate W. From this state, the upper surface of the roller conveyor 21 and the lift pins descends below the upper surface of the chuck mechanism 51, whereby the substrate W is transferred to the chuck mechanism 51 (step S11). The chuck mechanism 51 sucks and holds the peripheral edge of the substrate W (step S12).

Thereafter, the substrate W is held at the periphery by the chuck mechanism 51 and is transported in a state where the central portion is maintained in a horizontal posture by the floating stage unit 3. Prior to that, the thickness of the substrate W is calculated. In the state where the chuck mechanism 51 holds the substrate W at the transfer start position, the upper surface region Wfa of the attracted portion Wc attracted by the attracting member 513 of the chuck 51R of the substrate W is shown in the column (b) of FIG. It faces the detection surface of the sensor 61 directly. Therefore, the sensor 61 detects the vertical position of the upper surface region Wfa of the attracted part Wc. That is, in the sensor 61, light is emitted from the light projecting unit, and light reflected by the upper surface region Wfa of the attracted part Wc is received by the light receiving unit, and from the detection surface to the upper surface of the attracted part Wc of the substrate W. Is obtained as the vertical position of the upper surface of the attracted part Wc (step S13). A signal indicating the vertical position is output from the sensor 61 to the control unit 9. Receiving this, the calculation means 92 reads the vertical position (distance Lv) of the suction surface 513a from the storage means 91 as the vertical position of the lower surface Wb of the substrate W. This is because the lower surface Wb of the substrate W is adsorbed on the adsorption surface 513a, and the vertical position thereof coincides with the vertical position of the adsorption surface 513a. Thus, since the vertical positions of the upper surface and the lower surface of the substrate W are obtained, the calculation means 92 calculates the plate thickness D of the substrate W as follows: D = Lv−La
(Step S14). The plate thickness D calculated in this way is stored in the storage means 91.

  Subsequently, the chuck mechanism 51 moves in the (+ X) direction, so that the substrate W is transported to the application start position (step S15). At the same time, the nozzle 71 is moved and positioned from the preliminary discharge position to the application position (step S16). As shown in the column (c) of FIG. 6, the application start position is such that the downstream end of the substrate W (the leading side in the movement direction) comes to a position immediately below the nozzle 71 positioned at the application position. The position of W. In many cases, the coating liquid is not applied to the end portion of the substrate W as a blank region. In such a case, the downstream end portion of the substrate W is advanced from the position directly below the nozzle 71 by the length of the blank region. Becomes the application start position.

When the nozzle 71 is positioned at the application position, the vertical position of the upper surface Wf of the substrate W is acquired (step S16) and the flying height is calculated (step S17) prior to the discharge of the application liquid. That is, when the nozzle 71 is positioned at the application position, the sensor 62 attached to the nozzle 71 is positioned immediately above the substrate W positioned at the application start position, as shown in the column (c) of FIG. In the sensor 62, light is emitted from the light projecting unit, and light reflected by the upper surface Wf of the substrate W is received by the light receiving unit, and a distance Ld from the detection surface to the upper surface Wf of the substrate W is lifted by the coating stage 32. This is acquired as the vertical position of the upper surface of the substrate W thus obtained (step S17). Then, a signal indicating the vertical position is output from the sensor 62 to the control unit 9. Receiving this, the calculation means 92 reads the vertical position (Lb) of the stage upper surface 321 and the plate thickness D of the substrate W from the storage means 91. Then, the calculation means 92 calculates the flying height Hb of the substrate W as follows: Hb = Lb−Ld−D
(Step S18). The flying height Hb calculated in this way is stored in the storage unit 91 and displayed on a display unit (liquid crystal display or the like) (not shown). As a result, the flying height Hb can be notified to the user.

  When the flying height calculation process is completed in this way, the coating process is executed as follows (step S19). That is, the coating liquid discharged from the discharge port of the nozzle 71 is deposited on the upper surface Wf of the substrate W. Further, when the chuck mechanism 51 transports the substrate W at a constant speed, the nozzle 71 performs a coating operation for coating the coating liquid on the upper surface Wf of the substrate W, and the substrate upper surface Wf is coated with a constant thickness by the coating liquid. A film is formed.

  The application operation is continued until the substrate W is transported to the end position where application should be completed (step S20). When the substrate W reaches the end position (YES in step S20), the nozzle 71 is separated from the application position and returned to the preliminary discharge position, and the preliminary discharge process is executed again. Further, when the chuck mechanism 51 reaches the conveyance end position where the downstream end of the substrate W is positioned on the output transfer unit 4, the movement of the chuck mechanism 51 is stopped and the suction holding is released. And the raising of the roller conveyor 41 of the output transfer part 4 and the raising of the exit floating stage 33 are sequentially started.

  Then, the roller conveyor 41 and the outlet floating stage 33 rise above the upper surface of the chuck mechanism 51, so that the substrate W is separated from the chuck mechanism 51. When the roller conveyor 41 rotates in this state, a propulsive force in the (+ X) direction is applied to the substrate W. Accordingly, when the substrate W moves in the (+ X) direction, the substrate W is further carried out in the (+ X) direction by the cooperation of the roller conveyor 41 and the roller conveyor 111 of the output conveyor 110 (step S21), and finally downstream. It is paid out to the side unit. If there is a next substrate to be processed, the same processing as described above is repeated (step S22), and if not, the processing ends. At this time, the nozzle 71 is returned to the standby position.

  As described above, in this embodiment, the vertical position (distance Lv) of the suction surface 513a of the suction member 513 that holds the lower surface Wb of the substrate W is the vertical position of the lower surface Wb of the substrate W sucked by the suction member 513. And the thickness D of the substrate W is calculated based on this and the vertical position (distance La) of the upper surface region Wfa of the attracted part Wc detected by the sensor 61. Therefore, the thickness D of the substrate W can be derived with high accuracy. Then, the floating amount of the substrate W based on the vertical position (distance Ld) of the upper surface of the substrate W levitated by the coating stage 32, the vertical position (distance Lb) of the stage upper surface 321 of the coating stage 32, and the plate thickness D. Hb is calculated. Therefore, regardless of whether the substrate W is transmissive to light used by the sensor 61 or non-transmissive, that is, regardless of the type of the substrate W, the substrate W The flying height can be obtained with high accuracy.

  In the above-described embodiment, the sensor 61 for measuring the plate thickness is disposed vertically above the substrate W transported by the chuck mechanism 51, and the vertical direction of the suction surface 513a is not contacted from above the chuck mechanism 51 and the substrate W. The position and the vertical position of the upper surface region Wfa of the attracted part Wc are detected. For this reason, not only can the interference between the sensor 61 and the chuck mechanism 51 and the substrate W be surely avoided, but also the substance released from the substrate W during the transfer of the substrate W adheres to the sensor 61 and the detection accuracy decreases. Can be reliably prevented.

  Further, in the above-described embodiment, the thickness measurement sensor 61 is disposed upstream of the flying height measurement sensor 62 in the transport direction X of the substrate W, so that the flying height Hb is accurately calculated before the coating process. can do.

  Further, in the above-described embodiment, the thickness measurement sensor 61 is disposed upstream of the flying height measurement sensor 62 in the transport direction X of the substrate W. For this reason, before execution of the coating process on the substrate W, the plate thickness and the flying height of the substrate W can be obtained, and the coating process can be favorably controlled based on them. For example, when the calculated plate thickness or flying height exceeds the allowable range of the coating process, the coating process can be stopped, and a useless coating process can be avoided.

  As described above, in this embodiment, the chuck mechanism 51 functions as the “conveying unit” of the present invention. The application stage 32 corresponds to an example of the “stage” of the present invention. The sensors 61 and 62 correspond to examples of the “plate thickness measuring sensor” and the “levitation measuring sensor” of the present invention, respectively, and the functions as the plate thickness calculating unit 921 and the flying height calculating unit 922. The “floating amount calculation device” according to the present invention is configured by the control unit 9 having Steps S3 and S6 correspond to an example of the “first step” of the present invention, and steps S13, S14, S17, and S18 are the “second step”, “third step”, and “fourth step” of the present invention, respectively. ”And“ fifth step ”.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the plate thickness measurement sensors 61 are arranged only corresponding to the chuck 51R on the (−X) direction side, but the number and arrangement positions of the sensors 61 are limited to this. The sensor 61 may be provided corresponding to at least one of the four chucks 51R, 51R, 51L, and 51L.

  In the above embodiment, the levitation measurement sensor 62 is attached to the nozzle 71, but may be provided separately from the nozzle 71.

  In the above embodiment, the sensors 61 and 62 are optical sensors, but other non-contact sensors can be used. Moreover, although the positions of the detection surfaces of the sensors 61 and 62 are made to coincide in the vertical direction, they may be made different.

  The present invention is applied to a coating apparatus and a coating method for applying a coating liquid on the upper surface of a substrate while being transported in a horizontal direction in a state where the substrate is lifted from a stage, and to a floating amount calculation apparatus for calculating a floating amount in the coating apparatus. be able to.

DESCRIPTION OF SYMBOLS 1 ... Coating apparatus 32 ... Coating stage (stage)
51 ... Chuck mechanism (conveyance unit)
DESCRIPTION OF SYMBOLS 61 ... Sensor for plate thickness measurement 62 ... Sensor for plate thickness measurement 71 ... Nozzle 92 ... Calculation means 321 ... Upper surface of stage 513 ... Adsorption member 513a ... Adsorption surface of (adsorption member) 921 ... Plate thickness calculation part 922 ... Flying amount Calculation unit W ... Substrate Wf ... Upper surface of substrate Wb ... Lower surface of (substrate) Wc ... Adsorption site (of substrate)

Claims (5)

The lower surface is partially held by the suction member of the transport unit and is transported to the stage by the transport unit. The substrate is floated upward from the stage by applying buoyancy to the substrate and the nozzle is lifted to the substrate in the lifted state. A flying height calculation device that calculates the flying height of the substrate from the stage in a coating apparatus that discharges and coats a coating liquid from
A plate thickness measurement sensor that detects a vertical position of an adsorption surface that adsorbs the lower surface of the substrate of the adsorption member and a vertical position of an upper surface region of the adsorption target portion adsorbed by the adsorption member of the substrate. When,
A levitation measurement sensor for detecting a vertical position of the upper surface of the stage and a vertical position of the upper surface of the substrate conveyed above the stage;
A plate thickness calculation unit that calculates the plate thickness of the substrate based on the vertical position of the suction surface detected by the plate thickness measurement sensor and the vertical position of the upper surface region of the attracted portion;
Based on the vertical position of the upper surface of the stage and the vertical position of the upper surface of the substrate detected by the levitation measurement sensor, and the plate thickness calculated by the plate thickness calculation unit, the flying height of the substrate is calculated. A flying height calculation apparatus comprising: a flying height calculation unit for calculating. The flying height calculation device according to claim 1,
The plate thickness measurement sensor is arranged vertically above the substrate conveyed by the conveyance unit, and is in a non-contact state from above the conveyance unit and the substrate, so that the vertical position of the adsorption surface and the adsorption site A flying height calculation device that is a non-contact sensor that detects a vertical position of an upper surface region. The flying height calculation device according to claim 1 or 2,
In the conveyance direction of the substrate by the conveyance unit, the plate thickness measurement sensor is disposed on the upstream side of the levitation measurement sensor. A suction unit that partially sucks and holds the lower surface of the substrate, and a transport unit that transports the substrate in a predetermined transport direction while holding the substrate by the suction member;
A stage for floating the substrate by applying buoyancy to the substrate conveyed by the conveyance unit from below;
A nozzle for discharging and applying a coating liquid onto the substrate that has been levitated from the stage;
A plate thickness measurement sensor that detects a vertical position of an adsorption surface that adsorbs the lower surface of the substrate of the adsorption member and a vertical position of an upper surface region of the adsorption target portion adsorbed by the adsorption member of the substrate. When,
A levitation measurement sensor for detecting a vertical position of the upper surface of the stage and a vertical position of the upper surface of the substrate conveyed above the stage;
A plate thickness calculation unit that calculates the plate thickness of the substrate based on the vertical position of the suction surface detected by the plate thickness measurement sensor and the vertical position of the upper surface region of the attracted portion;
Based on the vertical position of the upper surface of the stage and the vertical position of the upper surface of the substrate detected by the levitation measurement sensor, and the plate thickness calculated by the plate thickness calculation unit, the flying height of the substrate is calculated. A coating apparatus comprising: a flying height calculation unit for calculating. The lower surface is partially held by the suction member of the transport unit and is transported to the stage by the transport unit. The substrate is floated upward from the stage by applying buoyancy to the substrate and the nozzle is lifted to the substrate in the lifted state. A coating method in which a coating solution is discharged from a coating,
A first step of detecting a vertical position of an adsorption surface that adsorbs a lower surface of the substrate of the adsorption member and a vertical position of an upper surface of the stage before applying the coating liquid to the substrate;
A second step of detecting a vertical position of an upper surface region of an adsorbed part of the substrate adsorbed by the adsorbing member after the substrate is held by the adsorbing member;
A third step of calculating the thickness of the substrate based on the vertical position of the suction surface and the vertical position of the upper surface region of the attracted part;
A fourth step of detecting a vertical position of the upper surface of the substrate that is transported above the stage by the transport unit while being held by the suction member;
A fifth step of calculating the flying height of the substrate based on the vertical position of the upper surface of the stage and the vertical position of the upper surface of the substrate and the plate thickness calculated in the third step. A coating method characterized by the above.

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