JP6890438B2 - Floating amount calculation device, coating device and coating method - Google Patents

Description

The present invention relates to a coating device and a coating method for applying a coating liquid to the upper surface of a substrate while being transported in a horizontal direction while floating the substrate from the stage, and a levitation amount calculation device for calculating a levitation amount in the coating device. .. The above-mentioned substrates include a semiconductor substrate, a photomask substrate, a liquid crystal display substrate, an organic EL display substrate, a plasma display substrate, a FED (Field Emission Display) substrate, an optical disk substrate, a magnetic disk substrate, and an optical disk. Includes magnetic disk substrates and the like.

In the manufacturing process of electronic parts such as semiconductor devices and liquid crystal display devices, a coating device is used in which a coating liquid is discharged onto the upper surface of a substrate and applied to the upper surface of the substrate. For example, in the coating apparatus described in Patent Document 1, a coating liquid is sent to a slit nozzle by a pump while transporting the substrate in a state where gas is blown onto the lower surface of the substrate to raise the substrate from the stage, and the coating liquid is discharged from the slit nozzle. The coating liquid is applied to almost the entire surface of the substrate by discharging it from the outlet to the surface of the substrate.

Patent No. 5346643

In the device described in Patent Document 1, an optical sensor for detecting the floating amount of the substrate with respect to the slit nozzle in a non-contact manner is installed. Then, the position of the slit nozzle in the vertical direction (hereinafter referred to as "vertical position") is adjusted based on the detection result by the optical sensor. Here, when the substrate is made of a transparent material, three types of vertical positions (the vertical position of the upper surface of the surfaced substrate, the vertical position of the lower surface of the substrate, and the vertical position of the upper surface of the stage) are performed by the sensor. It is possible to detect the directional position), and it is possible to calculate the plate thickness of the substrate and the amount of levitation from the stage based on these vertical positions.

However, it is difficult to detect the vertical position of the lower surface of the substrate on a substrate containing a light-shielding material, for example, a substrate on which metal is vapor-deposited. Therefore, in the above apparatus, the coating process is performed on the premise that the substrate is levitated with a gas spraying condition on the lower surface of the substrate, for example, a floating amount corresponding to the gas flow rate. Therefore, for example, if the floating amount is small or becomes zero due to fluctuations in the gas flow rate, the substrate can not be conveyed satisfactorily, and as a result, the accuracy of the coating process may be lowered. As described above, although the levitation amount is an important physical quantity for performing a high-precision coating process satisfactorily, a fixed value may be used as described above. Therefore, conventionally, in a coating technique for performing a coating process while floating a substrate, there has been a demand for a technique for accurately obtaining a floating amount regardless of the type of substrate.

The present invention has been made in view of the above problems, and in a coating apparatus for applying a coating liquid to a substrate while transporting the substrate while floating it from the stage, the amount of levitation 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 suction member of the transport portion and transported to the stage by the transport portion. A buoyancy force is applied to the substrate from below to float the substrate upward from the stage and in a floating state. It is a floating amount calculation device that calculates the floating amount of the substrate from the stage in the coating device that discharges the coating liquid from the nozzle to the substrate of the above, and is the vertical position of the suction surface that sucks the lower surface of the substrate among the suction members. And the plate thickness measurement sensor that detects the vertical position of the upper surface region of the suctioned part of the substrate that is attracted by the suction member, the vertical position of the upper surface of the stage, and the substrate conveyed above the stage. The plate thickness of the substrate is calculated based on the levitation measurement sensor that detects the vertical position of the upper surface, 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 suctioned part. The amount of levitation of the substrate based on the plate thickness calculation unit, 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. It is characterized in that the plate thickness measurement sensor is arranged on the upstream side of the levitation measurement sensor in the transfer direction of the substrate by the transfer unit .

A second aspect of the present invention is a coating device, which has a suction member that partially sucks 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 stage that gives buoyancy to the substrate transported by the transport unit from below to levitate the substrate, a nozzle that discharges and applies the coating liquid to the substrate levitated from the stage, and the lower surface of the substrate among the suction members. A plate thickness measurement sensor that detects the vertical position of the suction surface to be sucked and the vertical position of the upper surface region of the suctioned part of the substrate that is sucked by the suction member, the vertical position of the upper surface of the stage, and the stage. The levitation measurement sensor that detects the vertical position of the upper surface of the substrate conveyed above, and the vertical position of the suction surface and the vertical position of the upper surface region of the suctioned part detected by the plate thickness measurement sensor. The plate thickness calculation unit that calculates the plate thickness of the substrate based on it, 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. A levitation amount calculation unit that calculates the levitation amount of the substrate based on the above is provided , and the plate thickness measurement sensor is arranged on the upstream side of the levitation measurement sensor in the transfer direction of the substrate by the transfer unit. There is.

Further, in the third aspect of the present invention, the lower surface is partially held by the suction member of the transport portion and transported to the stage by the transport portion. The substrate is fed with buoyancy from below to float the substrate upward from the stage. This is a coating method in which a coating liquid is discharged from a nozzle onto a floating substrate, and a suction surface that sucks the lower surface of the substrate among the suction members by a plate thickness measurement sensor before the coating liquid is applied to the substrate. It detects the vertical position, a first step of detecting the vertical position location of the upper surface of the stage from the floating measurement sensor, of the adsorption sites adsorbed by the adsorption member of the substrate after the substrate has been held by the suction member The second step of detecting the vertical position of the upper surface region with the plate thickness measurement sensor, and the third step of calculating the plate thickness of the substrate based on the vertical position of the suction surface and the vertical position of the upper surface region of the suctioned portion. The fourth step of detecting the vertical position of the upper surface of the substrate, which is held by the suction member and conveyed above the stage by the transport unit, from the levitation measurement sensor, and the vertical position of the upper surface of the stage and the upper surface of the substrate. It is provided with a fifth step of calculating the floating amount of the substrate based on the vertical position and the plate thickness calculated in the third step, and the plate thickness measuring sensor is for levitation measurement in the transport direction of the substrate by the transport unit. The feature is that it is located on the upstream side of the sensor.

In the invention configured in this way, a part of the lower surface of the substrate (the lower surface of the suctioned portion) is attracted to the suction member of the transport portion and held by the transport portion, so that the vertical position of the lower surface of the substrate is the suction member. Of these, it coincides with the vertical position of the suction surface that sucks the lower surface of the substrate. Therefore, the vertical position of the suction surface is detected before the substrate is held by the suction member, so that the vertical position of the lower surface of the suctioned portion is substantially detected. Then, by detecting the vertical position of the upper surface region of the portion to be adsorbed after holding the substrate, the vertical positions of the upper surface and the lower surface of the substrate are aligned, and the plate thickness of the substrate can be calculated accurately. On the other hand, when the vertical position of the upper surface of the stage is detected before the substrate is conveyed and the vertical position of the upper surface of the substrate conveyed above the stage is detected, the vertical position and the thickness of the substrate are determined. The floating amount of the substrate is calculated with high accuracy based on.

As described above, according to the present invention, the plate thickness of the substrate is calculated based on the vertical position of the adsorption surface that adsorbs the lower surface of the substrate and the vertical position of the upper surface region of the portion to be adsorbed, and the plate thickness is calculated. Since the floating amount 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 floating amount from the stage can be obtained with high accuracy.

It is a figure which shows typically the whole structure of the coating apparatus which is equipped with one Embodiment of the levitation amount calculation apparatus which concerns on this invention. It is a top view of the coating apparatus seen from the vertical direction. It is a top view which removed the coating mechanism from FIG. FIG. 2 is a cross-sectional view taken along the line AA of FIG. It is a flowchart which shows the flow of the floating amount calculation process and coating process by this coating apparatus. It is a figure which shows typically the positional relationship of each part in a processing process.

FIG. 1 is a diagram schematically showing an overall configuration of a coating device equipped with an embodiment of a levitation amount calculation device according to the present invention. The coating device 1 is a slit coater that applies a coating liquid to the upper surface Wf of the substrate W that is conveyed in a horizontal posture from the left-hand side to the right-hand side in FIG. In each of the following figures, in order to clarify the arrangement relationship of each part of the device, 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 of FIG. 1 is referred to as "+ X direction". , The reverse direction is referred to as "-X direction". Further, of the horizontal directions Y orthogonal to the X direction, the front side of the device is referred to as the "-Y direction", and the back side of the device is referred to as the "+ 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, an outline of the configuration and operation of the coating device 1 will be described with reference to FIG. 1, and then a more detailed structure of each part will be described. The basic configuration and operating principle of the coating device 1 are the same as those described in Japanese Patent No. 5346643 (Patent Document 1) previously disclosed by the applicant of the present application. Therefore, in the present specification, among the respective configurations of the coating apparatus 1, those to which the same configurations as those described in these publicly known documents can be applied, and those whose structures can be easily understood from the descriptions in these documents. The detailed description will be omitted, and the characteristic parts of the present embodiment will be mainly described.

In the coating device 1, the input conveyor 100, the input transfer unit 2, the levitation 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. As will be described in detail below, a transport path for the substrate W extending in a substantially horizontal direction is formed by these. In the following description, when the positional relationship is shown in relation to 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". The "side" may be simply abbreviated as the "downstream side". In this example, the (−X) side corresponds to the “upstream side” and the (+ X) side corresponds to the “downstream side” relative to 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 drive mechanism 102 that rotationally drives the roller conveyor 101, and the rotation of the roller conveyor 101 causes the substrate W to be conveyed in a horizontal posture on the downstream side, that is, in the (+ X) direction. 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 raising and lowering the roller conveyor 21. As the roller conveyor 21 rotates, the substrate W is further conveyed in the (+ X) direction. Further, the vertical position of the substrate W is changed by moving the roller conveyor 21 up and down. The substrate W is transferred from the input conveyor 100 to the levitation stage unit 3 by the input transfer unit 2 configured in this way.

The levitation stage portion 3 includes a flat plate-shaped stage divided into three along the transport direction Dt of the substrate. That is, the levitation stage portion 3 includes an inlet levitation stage 31, a coating stage 32, and an outlet levitation stage 33, and the upper surfaces of each of these stages form a part of the same plane. A large number of ejection holes for ejecting compressed air supplied from the levitation control mechanism 35 are provided in a matrix on the upper surfaces of the inlet levitation stage 31 and the outlet levitation stage 33, and the buoyancy applied from the ejected airflow causes the buoyancy. The substrate W floats. In this way, 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 levitation amount 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 levitation control mechanism 35 controls the amount of compressed air ejected from the ejection hole and the amount of suction from the suction hole, so that the distance between the lower surface Wb of the substrate W and the upper surface of the coating stage 32 is precisely controlled. As a result, the vertical position of the upper surface Wf of the substrate W passing above the coating stage 32 is controlled to a specified value. As a specific configuration of the levitation stage portion 3, for example, the one described in Japanese Patent No. 5346643 (Patent Document 1) can be applied. The amount of levitation at the coating stage 32 is calculated by the control unit 9 based on the detection results by the sensors 61 and 62, which will be described in detail later, and can be adjusted with high accuracy by airflow control.

The inlet levitation stage 31 is provided with a lift pin 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 pin.

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 entrance levitation stage 31. The inlet levitation stage 31, the coating stage 32, and the outlet levitation stage 33 support the substrate W in a levitation state, but do not have a function of moving the substrate W in the horizontal direction. The substrate W in the levitation stage portion 3 is conveyed by the substrate transport portion 5 arranged below the inlet levitation stage 31, the coating stage 32, and the outlet levitation stage 33.

The substrate transport portion 5 includes a chuck mechanism 51 that supports the substrate W from below by partially abutting the lower peripheral edge portion of the substrate W, and a suction member at the upper end of the chuck mechanism 51 (later shown in FIGS. 3, 4, and 6). A suction / running control mechanism 52 having a function of applying a negative pressure to a suction pad (not shown) provided in reference numeral 513) to suck and hold the substrate W and a function of reciprocating the chuck mechanism 51 in the X direction. I have. When the chuck mechanism 51 holds the substrate W, the lower surface Wb of the substrate W is located higher than the upper surface of each stage of the levitation stage portion 3. Therefore, the substrate W maintains the horizontal posture as a whole by the buoyancy applied from the buoyancy stage portion 3 while the peripheral portion is attracted and held by the chuck mechanism 51. A sensor 61 for measuring the plate thickness is arranged near the roller conveyor 21 in order to detect the vertical position of the upper surface of the substrate W at the stage where the lower surface Wb of the substrate W is partially held by the chuck mechanism 51. .. By locating the chuck (see reference numeral 51R in FIGS. 3, 4, and 6 later) in a state where the substrate W is not held, the sensor 61 is positioned on the upper surface of the suction member, that is, the suction member. The vertical position of the surface (see reference numeral 513a in FIG. 6 later) can be detected.

The chuck mechanism 51 holds the substrate W carried from the input transfer unit 2 to the levitation stage unit 3, and the chuck mechanism 51 moves in the (+ X) direction in this state, so that the substrate W is moved above the inlet levitation stage 31. Is conveyed above the outlet levitation stage 33 via above the coating stage 32. The conveyed substrate W is delivered to the output transfer unit 4 arranged on the (+ X) side of the outlet levitation stage 33.

The output transfer unit 4 includes a roller conveyor 41 and a rotation / elevating drive mechanism 42 having a function of rotationally driving the roller conveyor 41 and a function of raising and lowering the roller conveyor 41. By rotating the roller conveyor 41, a propulsive force is applied to the substrate W in the (+ X) direction, and the substrate W is further conveyed along the transfer 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 output transfer unit 4 transfers the substrate W to the output conveyor 110 from above the outlet levitation stage 33.

The output conveyor 110 includes a roller conveyor 111 and a rotation drive mechanism 112 that rotationally drives the roller conveyor 111. The rotation of the roller conveyor 111 further conveys the substrate W in the (+ X) direction, and finally outside the coating device 1. Will be paid out to. The input conveyor 100 and the output conveyor 110 may be provided as part of the configuration of the coating device 1, but may be separate from the coating device 1. Further, for example, a substrate dispensing mechanism of another unit provided on the upstream side of the coating device 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 device 1 may be used as the output conveyor 110.

A coating mechanism 7 for applying the coating liquid to the upper surface Wf of the substrate W is arranged on the transport path of the substrate W transported in this way. The coating mechanism 7 includes a nozzle 71, which is a slit nozzle, and a maintenance unit 75 for performing maintenance on the nozzle 71. The 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 to the lower part of the nozzle.

The nozzle 71 can be moved and positioned in the X direction and the Z direction by the positioning mechanism 73. The positioning mechanism 73 positions the nozzle 71 at the coating position (the position indicated by the dotted line) above the coating stage 32. The coating liquid is discharged from the nozzle positioned at the coating position and coated on the substrate W conveyed between the coating liquid and the coating stage 32. In this way, the coating liquid is applied to the substrate W. The nozzle 71 is provided with 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 levitation amount as described in detail later. It is attached.

The maintenance unit 75 includes a butt 751 for storing a cleaning liquid for cleaning the nozzle 71, a preliminary discharge roller 752, a nozzle cleaner 753, and a maintenance control mechanism 754 that controls the operation of the preliminary discharge roller 752 and the nozzle cleaner 753. I have. As a specific configuration of the maintenance unit 75, for example, the configuration described in Japanese Patent Application Laid-Open No. 2010-240550 can be applied.

At a 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 to the upper surface of the preliminary discharge roller 752. Nozzle. The nozzle 71 is positioned at the preliminary discharge position prior to being positioned at the coating position, and discharges a predetermined amount of the coating liquid from the discharge port to execute the preliminary discharge process. By causing the nozzle 71 before being moved to the coating position to perform the preliminary ejection process in this way, the ejection of the coating liquid at the coating position can be stabilized from the initial stage.

When the maintenance control mechanism 754 rotates the preliminary discharge roller 752, the discharged coating liquid is mixed with the cleaning liquid stored in the vat 751 and recovered. Further, when the nozzle 71 is in the upper position (first cleaning position) of the nozzle cleaner 753, the nozzle cleaner 753 moves in the Y direction while discharging the cleaning liquid, so that the nozzle 71 adheres to the discharge port of the nozzle 71 and its surroundings. The coating liquid is washed away.

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

In addition, the coating device 1 is provided with a control unit 9 for controlling the operation of each part of the device. The control unit 9 is a storage means 91 that stores a predetermined control program and various data, a calculation means 92 such as a CPU that causes each part of the device to execute a predetermined operation by executing this control program, and information exchange with a user or an external device. The interface means 93 and the like are provided. In the present embodiment, as will be described later, the calculation means 92 calculates the plate thickness and the levitation amount 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 levitation amount calculation unit 922.

FIG. 2 is a plan view of the coating apparatus viewed from above vertically. Further, FIG. 3 is a plan view of FIG. 2 with the coating mechanism removed. Further, FIG. 4 is a cross-sectional view taken along the line AA of FIG. Hereinafter, a specific mechanical configuration of the coating device 1 will be described with reference to these figures. For some mechanisms, a more detailed structure can be understood by referring to the description of Japanese Patent No. 5346643 (Patent Document 1). In addition, in FIGS. 2 and 3, the description of the rollers included in the input conveyor 100 and the like is omitted.

The nozzle unit 70 of the coating mechanism 7 has a crosslinked structure as shown in FIGS. 2 and 4. Specifically, the nozzle unit 70 is a pair of column members 732 and 733 erected above the base 10 at both ends of the beam member 731 extending in the Y direction above the levitation stage portion 3 in the Y direction. 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 movably supported by the elevating mechanism 734. 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 movably supported by the elevating mechanism 735. By interlocking the elevating mechanisms 734 and 735 in response to the control command from the control unit 9, the beam member 731 moves in the vertical direction (Z direction) while maintaining the horizontal posture.

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

The pillar members 732 and 733 are configured to be movable in the X direction on the base 10. Specifically, a pair of traveling guides 81L and 81R extending in the X direction are attached to the upper surfaces of the (+ Y) side and (-Y) side ends of the base 10, respectively, and the pillar member 732 is attached. Is engaged with the traveling guide 81L on the (+ Y) side via a slider 736 attached to the lower portion thereof. The slider 736 is movable in the X direction along the traveling guide 81L. Similarly, the pillar member 733 is engaged with the traveling guide 81R on the (-Y) side via the slider 737 attached to the lower portion thereof, and is movable in the X direction.

Further, the pillar 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 as stators to the base 10 along the X direction, and the coil modules are attached to the lower parts of the column members 732 and 733 as movers. By operating the linear motors 82L and 82R in response to the control command from the control unit 9, the entire nozzle unit 70 moves along the X direction. As a result, the nozzle 71 can be moved in the X direction. The positions of the column members 732 and 733 in the X direction can be detected by the linear scales 83L and 83R provided in the vicinity of the sliders 736 and 737.

In this way, 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, by controlling these mechanisms by the control unit 9, positioning of the nozzle 71 at each stop position (coating position, preliminary discharge position, etc.) is realized. Therefore, the elevating mechanism 734, 735, the linear motors 82L, 82R, the control unit 9 for controlling these, and the like are integrally functioning as the positioning mechanism 73 of FIG.

The maintenance unit 75 has a structure in which a preliminary discharge roller 752 and a nozzle cleaner 753 are housed 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. A 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.

Below both ends of the plate 764 in the Y direction, a pair of traveling guides 84L and 84R extend in the X direction on the base 10. Both ends of the plate 764 in the Y direction are engaged with the traveling guides 84L and 84R via the sliders 766 and 767. Therefore, the maintenance unit 75 can move in the X direction along the traveling guides 84L and 84R. A linear motor 85 is provided below the end of the plate 764 in the (−Y) direction. The linear motor 85 may be provided below the (+ Y) direction ends of the plate 764, or may be provided below both ends in the Y direction.

In the linear motor 85, a magnet module is extended as a stator to 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 in response to the 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. 3 and 4. The chuck mechanism 51 includes a pair of chucks 51L and 51R having shapes symmetrical with respect to the XZ plane and arranged apart from each other in the Y direction. Of these, the chuck 51L arranged on the (+ Y) side is supported by a traveling guide 87L extending in the X direction on the base 10 so as 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 connecting portion connecting these plate portions. Sliders 511 are provided at the lower portions of the two plate portions of the base portion 512, and the slider 511 is engaged with the traveling guide 87L so that the base portion 512 can travel in the X direction along the traveling guide 87L. ing.

Above the two plate portions of the base portion 512, suction members 513 and 513 are provided which extend upward and are provided with suction pads (not shown) at the upper ends thereof. When the base portion 512 moves in the X direction along the traveling guide 87L, the two suction members 513 and 513 move in the X direction integrally with the base portion 512. The two plate portions of the base portion 512 may be separated from each other, and the plate portions may move in the X direction while maintaining a certain distance to apparently function as an integral base portion. If this distance is set according to the length of the substrate, it becomes possible to correspond to substrates of various lengths.

The chuck 51L can be moved in the X direction by the linear motor 88L. That is, the magnet module of the linear motor 88L extends in the X direction to the base 10 as a stator, and the coil module is attached to the lower part of the chuck 51L as a mover. When the linear motor 88L operates in response to the control command from the control unit 9, 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 51R provided on the (-Y) side also includes a base portion 512 having two plate portions and a connecting portion, and suction members 513 and 513. However, its shape is symmetrical with respect to the chuck 51L with respect to the XZ plane. Each plate portion is engaged with the traveling guide 87R by the slider 511. Further, the chuck 51R can be moved in the X direction by the linear motor 88R. That is, the magnet module of the linear motor 88R extends in the X direction to the base 10 as a stator, and the coil module is attached to the lower part of the chuck 51R as a mover. By operating the linear motor 88R in response to the control command from the control unit 9, the chuck 51R moves along the X direction. The position of the chuck 51R in the X direction can be detected by the linear scale 89R.

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

As shown in FIG. 3, each of the four suction members 513 is 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 (+ Y) side peripheral edge portion of the substrate W and the upstream side end portion and the downstream side end portion in the transport direction Dt, respectively. On the other hand, the two suction members 513 and 513 of the chuck 51R hold the (−Y) side peripheral edge portion of the substrate W and the upstream side end portion and the downstream side end portion in the transport direction Dt, respectively. Negative pressure is supplied to the suction pads of each suction member 513 as needed, so that the four corners of the substrate W are suction-held from below by the chuck mechanism 51.

The substrate W is conveyed by the chuck mechanism 51 moving in the X direction while holding the substrate W. In this way, the linear motors 88L and 88R, the mechanism for supplying negative pressure to each suction member 513 (not shown), 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 each stage of the levitation stage portion 3, that is, the inlet levitation stage 31, the coating stage 32, and the outlet levitation stage 33. The substrate W is conveyed in this state. Since the chuck mechanism 51 only holds a part of the outer peripheral edge portion of the substrate W in the Y direction from the central portion facing each stage 31, 32, 33, the central portion of the substrate W is located on the peripheral edge portion. On the other hand, it will bend downward. The levitation stage portion 3 has a function of controlling the vertical position of the substrate W and maintaining the horizontal posture by applying buoyancy to the central portion of the substrate W.

Of the stages of the levitation stage portion 3, the outlet levitation stage 33 has a lower position in which the upper surface position is lower than the upper surface position of the chuck mechanism 51 and an upper position in which the upper surface position is higher than the upper surface position of the chuck mechanism 51. It is possible to go up and down between. For this purpose, the outlet levitation stage 33 is supported by an elevating drive mechanism 36.

Next, the floating amount 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 floating amount calculation process and the coating process in this coating device. Further, FIG. 6 is a diagram schematically showing the positional relationship of each part in the levitation amount calculation process, and the positional relationship of the chuck mechanism 51, the nozzle 71 and the substrate W in the levitation amount calculation process is schematically shown in the central region of the figure. In the left region, the positional relationship between the chuck mechanism 51 and the substrate W at a position directly below the sensor 61 is enlarged and shown, and in the right region, the sensor 62 when the nozzle 71 is positioned at the coating position. The positional relationship between the nozzle 71 and the substrate W at the position directly below is enlarged and shown. Based on the detection results of these sensors 61 and 62, the floating amount calculation is executed as one operation during the coating process.

In the coating device 1, the thickness of the substrate W and the amount of floating of the substrate W from the coating stage 32 are calculated during the execution of the coating process. For these calculations, 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 (hereinafter referred to as "reference information") is required. The reference information is not necessary for the coating process for each substrate, but it is necessary to acquire an appropriate timing and store it in the storage means 91. Therefore, in the present embodiment, the calculation means 92 appropriately acquires the reference information by controlling each part of the device according to the control program stored in advance in the storage means 91, and is conveyed by the input conveyor 100. The coating process for the substrate W is executed while measuring the thickness and the floating amount of the substrate W.

In the present embodiment, it is determined in step S1 whether or not it is the timing to acquire the reference information. Triggers for setting the timing include, for example, power-on, maintenance completion, reaching a predetermined value of the cumulative number of coated substrates W, or instructions from the user via an operation panel (not shown). Is done. At the stage of executing the step S1, the coating process has not been performed, the nozzle 71 is positioned at the standby position, and the discharge of the coating liquid is stopped. Further, the substrate W does not exist in the input transfer unit 2, the levitation stage unit 3, and the output conveyor 110. Further, the chuck mechanism 51 is retracted in the (+ X) direction from the transport start position (the position directly below the substrate W fed to the levitation stage portion 3 by the input transfer portion 2 as shown in the column (b) of FIG. 6). Is positioned at.

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 steps (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 movement positioning of the nozzle 71 from the standby position to the coating position is performed. As a result, the levitation measurement sensor 62 attached to the nozzle 71 is located directly above the upper surface of the coating stage 32. At this stage, as shown in column (a) of FIG. 6, the substrate W does not exist at a position directly below the nozzle 71, and the upper surface of the coating stage 32 (hereinafter referred to as “stage upper surface”) 321 is the detection surface of the sensor 62. Is directly facing. A floodlight (not shown) and a light receiver (not shown) are provided on the detection surface of the sensor 62, and light is emitted from the light projecting unit and the light reflected by the suction surface 513a is emitted from the light receiving unit. The light is received and the vertical position of the upper surface 321 of the stage is acquired (step S3). The same applies to the sensor 61 in that the sensor has a floodlight and a receiver in this way.

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

The step of acquiring the vertical position of the suction surface 513a (steps S5 to S7) is executed at the same time as or before and after the step of acquiring the vertical position of the stage upper surface 321 (steps S2 to S4). That is, in step S5, the chuck mechanism 51 moves in the (−X) direction and moves to the transfer start position. As a result, in the chuck mechanism 51, the chuck 51R on the (−X) direction side is located directly below the sensor 61 for measuring the plate thickness. Further, even 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 suction member 513 of the chuck 51R, that is, the suction surface 513a is the sensor 61. It faces the detection surface directly. In the sensor 61, light is emitted from the light projecting portion, light reflected by the suction surface 513a is received by the light receiving portion, 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). Then, 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 513a is stored in the storage means 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 levitation amount in this way, 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. Further, the compressed air is started to be ejected from the levitation stage portion 3 to prepare the substrate W to be carried in so that the substrate W can be levitation. When the nozzle 71 discharges a predetermined amount of the coating liquid toward the preliminary discharge roller 752 at the preliminary discharge position, the discharge amount of the coating liquid from the nozzle 71 can be stabilized. The nozzle 71 may be cleaned prior to the preliminary discharge process.

Next, the loading of the substrate W into the coating device 1 is started (step S9). The substrate W to be processed is placed on the input conveyor 100 by another processing unit on the upstream side, a transfer robot, or the like, and the substrate W is conveyed in the (+ X) direction by rotating the roller conveyor 101. At this time, the nozzle 71 executes the preliminary discharge process at the preliminary discharge position. Further, the chuck mechanism 51 is retracted and positioned on the downstream side of the inlet levitation stage 31.

When the input conveyor 100 and the input transfer unit 2 whose 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 becomes the substrate W by ejecting compressed air. It is conveyed to the upper part of the entrance levitation stage 31 that gives buoyancy to the conveyor. At this time, the upper surface of the entrance levitation stage 31 is below the upper surface of the roller conveyor 21, and the substrate W is in a state where the upstream end portion (rear end portion in the moving direction) rides on the roller conveyor 21. Therefore, the substrate W does not slide and move on the entrance levitation stage 31.

When the substrate W is carried into the inlet levitation stage 31 in this way, the lift pin provided on the inlet levitation stage 31 is positioned above the upper end of the lift pin drive mechanism 34 so as to protrude upward from the upper surface of the inlet levitation stage 31. .. As a result, both ends of the substrate W, more specifically, the substrate W with which the lift pin abuts, are lifted in the Y direction.

Then, the chuck mechanism 51 moves in the (−X) direction and moves to the transfer start position directly under the substrate W (step S10). Since both ends of the substrate W in the Y direction are lifted by the lift pins 311, it is possible to prevent the chuck mechanism 51 entering below 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 pin is lowered below the upper surface of the chuck mechanism 51, so that 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).

After that, the peripheral portion of the substrate W is held by the chuck mechanism 51, and the substrate W is conveyed in a state where the central portion is maintained in the horizontal posture by the levitation stage portion 3, but the plate thickness of the substrate W is calculated prior to that. When the chuck mechanism 51 holds the substrate W at the transfer start position, as shown in the column (b) of FIG. 6, the upper surface region Wfa of the suctioned portion Wc sucked by the suction member 513 of the chuck 51R in the substrate W It directly faces the detection surface of the sensor 61. Therefore, the vertical position of the upper surface region Wfa of the adsorbed portion Wc is detected by the sensor 61. That is, in the sensor 61, light is emitted from the light projecting portion, and the light reflected by the upper surface region Wfa of the adsorbed portion Wc is received by the light receiving portion, from the detection surface to the upper surface of the adsorbed portion Wc of the substrate W. The distance La is acquired as the vertical position of the upper surface of the adsorbed portion Wc (step S13). Then, a signal indicating the vertical position is output from the sensor 61 to the control unit 9. Upon receiving this, the calculation means 92 reads out 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 suction surface 513a, and its vertical position coincides with the vertical position of the suction surface 513a. In this way, since the vertical positions of the upper surface and the lower surface of the substrate W were obtained, the calculation means 92 calculated the plate thickness D of the substrate W by the following equation D = Lv-La.
Calculate according to (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 conveyed to the coating start position (step S15). In parallel with this, the movement positioning of the nozzle 71 from the preliminary discharge position to the coating position is performed (step S16). As shown in column (c) of FIG. 6, the coating start position is a substrate such that the end portion on the downstream side (head side in the moving direction) of the substrate W comes directly below the nozzle 71 positioned at the coating position. It is the position of W. In many cases, the coating liquid is not applied to the end portion of the substrate W as a margin region. In such a case, the downstream end portion of the substrate W is a position advanced by the length of the margin region from the position directly below the nozzle 71. Is the coating start position.

When the nozzle 71 is positioned at the coating position, the vertical position of the upper surface Wf of the substrate W is acquired (step S16) and the floating amount is calculated (step S17) prior to the discharge of the coating liquid. That is, when the nozzle 71 is positioned at the coating position, the sensor 62 attached to the nozzle 71 is located directly above the substrate W positioned at the coating start position as shown in the column (c) of FIG. In the sensor 62, light is emitted from the light projecting portion, light reflected by the upper surface Wf of the substrate W is received by the light receiving portion, and the distance Ld from the detection surface to the upper surface Wf of the substrate W rises by the coating stage 32. It is acquired as a vertical position on the upper surface of the board W (step S17). Then, a signal indicating the vertical position is output from the sensor 62 to the control unit 9. Upon receiving this, the calculation means 92 reads out 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 floating amount Hb of the substrate W by the following equation Hb = Lb-Ld-D.
Calculate according to (step S18). The levitation amount Hb calculated in this way is stored in the storage means 91 and displayed on a display means (such as a liquid crystal display) for which illustration is omitted. As a result, the user can be notified of the floating amount Hb.

When the floating amount 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 lands on the upper surface Wf of the substrate W. Further, when the chuck mechanism 51 conveys the substrate W at a constant speed, the nozzle 71 executes a coating operation of applying the coating liquid to the upper surface Wf of the substrate W, and the upper surface Wf of the substrate is coated with a constant thickness by the coating liquid. A film is formed.

The coating operation is continued until the substrate W is conveyed to the end position where the coating should be completed (step S20). When the substrate W reaches the end position (YES in step S20), the nozzle 71 is separated from the coating position and returned to the preliminary discharge position, and the preliminary discharge process is executed again. Further, when the chuck mechanism 51 reaches the transfer end position where the downstream end of the substrate W is located on the output transfer portion 4, the movement of the chuck mechanism 51 is stopped and the suction holding is released. Then, the ascent of the roller conveyor 41 of the output transfer unit 4 and the ascent of the outlet levitation stage 33 are sequentially started.

Then, the roller conveyor 41 and the outlet levitation stage 33 rise above the upper surface of the chuck mechanism 51, so that the substrate W is separated from the chuck mechanism 51. By rotating the roller conveyor 41 in this state, a propulsive force in the (+ X) direction is applied to the substrate W. As a result, when the substrate W moves in the (+ X) direction, the substrate W is further carried out in the (+ X) direction by the cooperation between 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 process as above is repeated (step S22), otherwise the process ends. At this time, the nozzle 71 is returned to the standby position.

As described above, in the present embodiment, the vertical position (distance Lv) of the suction surface 513a of the suction member 513 holding 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. The plate 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 adsorbed portion Wc detected by the sensor 61. Therefore, the plate thickness D of the substrate W can be derived with high accuracy. Then, the floating amount of the substrate W is based on the vertical position (distance Ld) of the upper surface of the substrate W floated 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 transparent or non-transparent to the light used by the sensor 61, that is, regardless of the type of the substrate W, the coating stage 32 is used. The amount of levitation can be obtained with high accuracy.

Further, in the above embodiment, the sensor 61 for measuring the plate thickness is arranged vertically above the substrate W conveyed by the chuck mechanism 51, and is in the vertical direction of the suction surface 513a from above the chuck mechanism 51 and the substrate W in a non-contact manner. The position and the vertical position of the upper surface region Wfa of the adsorbed portion Wc are detected. Therefore, not only the interference between the sensor 61 and the chuck mechanism 51 and the substrate W can be reliably avoided, but also the substance released from the substrate W during the transportation of the substrate W adheres to the sensor 61 and the detection accuracy is lowered. Can be reliably prevented.

Further, in the above embodiment, since the sensor 61 for measuring the plate thickness is arranged on the upstream side of the sensor 62 for levitation measurement in the transport direction X of the substrate W, the levitation amount Hb is accurately calculated before the coating process. can do.

Further, in the above embodiment, the sensor 61 for measuring the plate thickness is arranged on the upstream side of the sensor 62 for levitation measurement in the transport direction X of the substrate W. Therefore, the plate thickness and the floating amount of the substrate W can be obtained before the coating process is executed on the substrate W, and the coating process can be satisfactorily controlled based on these. For example, when the calculated plate thickness or floating amount exceeds the allowable range of the coating process, the coating process can be stopped, and unnecessary coating process can be avoided.

As described above, in this embodiment, the chuck mechanism 51 functions as the "conveying unit" of the present invention. Further, the coating stage 32 corresponds to an example of the "stage" of the present invention. Further, the sensors 61 and 62 correspond to examples of the "plate thickness measurement sensor" and the "levitation measurement sensor" of the present invention, respectively, and function as a plate thickness calculation unit 921 and a levitation amount calculation unit 922, respectively. The "floating amount calculation device" according to the present invention is configured by the control unit 9 having the above. Further, 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. It corresponds to an example of "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 embodiment, the sensor 61 for measuring the plate thickness is 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.

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

Further, in the above embodiment, the sensors 61 and 62 are both optical sensors, but other non-contact sensors can be used. Further, although the positions of the detection surfaces of the sensors 61 and 62 are matched in the vertical direction, they may be different.

The present invention is applied to a coating device and a coating method for applying a coating liquid to the upper surface of a substrate while being transported in a horizontal direction while being floated from a stage, and a floating amount calculating device for calculating a floating amount in the coating device in general. be able to.

1 ... Coating device 32 ... Coating stage (stage)
51 ... Chuck mechanism (conveyor)
61 ... Sensor for plate thickness measurement 62 ... Sensor for plate thickness measurement 71 ... Nozzle 92 ... Calculation means 321 ... Stage top surface 513 ... Adsorption member 513a ... Adsorption surface (of adsorption member) 921 ... Plate thickness calculation unit 922 ... Floating amount Calculation unit W ... Substrate Wf ... Upper surface (of the substrate) Wb ... Lower surface (of the substrate) Wc ...

Claims (4)

While the lower surface is partially held by the suction member of the transport unit, the substrate is transported to the stage by the transport unit. A buoyancy is applied to the substrate from below to float the substrate upward from the stage, and a nozzle is applied to the substrate in the floating state. It is a buoyancy amount calculation device that calculates the buoyancy amount of the substrate from the stage in the coating device that discharges and applies the coating liquid from the stage.
A sensor for measuring plate thickness that detects the vertical position of the suction surface that sucks the lower surface of the substrate among the suction members and the vertical position of the upper surface region of the suctioned portion that is sucked by the suction member of the substrate. When,
A levitation measurement sensor that detects the vertical position of the upper surface of the stage and the 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 and the vertical position of the upper surface region of the suctioned portion detected by the plate thickness measurement sensor.
The levitation amount of the substrate is determined 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. and a flying height calculation unit calculating,
A levitation amount calculation device, characterized in that the plate thickness measurement sensor is arranged on the upstream side of the levitation measurement sensor in the transfer direction of the substrate by the transfer unit. The levitation amount calculation device according to claim 1.
The plate thickness measurement sensor is arranged vertically above the substrate transported by the transport unit, and is a non-contact position of the suction surface in the vertical direction and the suctioned portion from above the transport unit and the substrate. A levitation amount calculation device that is a non-contact sensor that detects the vertical position of the upper surface region. A transport unit having a suction member that partially sucks 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 stage that gives buoyancy to the substrate transported by the transport unit from below to levitate the substrate.
A nozzle for discharging and applying a coating liquid to the substrate surfaced from the stage, and a nozzle for applying the coating liquid.
A sensor for measuring plate thickness that detects the vertical position of the suction surface that sucks the lower surface of the substrate among the suction members and the vertical position of the upper surface region of the suctioned portion that is sucked by the suction member of the substrate. When,
A levitation measurement sensor that detects the vertical position of the upper surface of the stage and the 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 and the vertical position of the upper surface region of the suctioned portion detected by the plate thickness measurement sensor.
The levitation amount of the substrate is determined 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. and a flying height calculation unit calculating,
A coating device characterized in that the plate thickness measurement sensor is arranged on the upstream side of the levitation measurement sensor in the transfer direction of the substrate by the transfer unit. While the lower surface is partially held by the suction member of the transport unit, the substrate is transported to the stage by the transport unit. A buoyancy is applied to the substrate from below to float the substrate upward from the stage, and a nozzle is applied to the substrate in the floating state. It is a coating method in which the coating liquid is discharged from the surface and applied.
Prior to coating the coating liquid on the substrate, the plate thickness measurement sensor detects the vertical position of the suction surface that sucks the lower surface of the substrate among the suction members , and the levitation measurement sensor detects the upper surface of the stage. a first step of detecting the vertical position location of,
A second step of detecting the vertical position of the upper surface region of the suctioned portion of the substrate, which is sucked by the suction member, after holding the substrate by the suction member by the plate thickness measuring sensor.
A third step of calculating the plate thickness of the substrate based on the vertical position of the suction surface and the vertical position of the upper surface region of the suctioned portion.
A fourth step of detecting the vertical position of the upper surface of the substrate, which is held by the suction member and transported above the stage by the transport unit, from the levitation measurement sensor.
A fifth step of calculating the floating amount of the substrate based on 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 third step is provided .
A coating method characterized in that the plate thickness measurement sensor is arranged on the upstream side of the levitation measurement sensor in the transfer direction of the substrate by the transfer unit.

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