JP6860357B2 - 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 a substrate by moving a nozzle that conveys the substrate and discharges the coating liquid from a discharge port in the transport direction of the substrate.

In the manufacturing process of electronic parts such as semiconductor devices and liquid crystal display devices, a coating device for applying a resist liquid (corresponding to an example of the "coating liquid" of the present invention) to the surface of a substrate is used. For example, in the coating apparatus described in Patent Document 1, the substrate is conveyed in a state where the substrate is floated by spraying gas on the back surface of the substrate. Further, the long nozzle is moved in the transport direction of the substrate, and the substrate is transported relative to the long nozzle. Then, the resist liquid is discharged from the long nozzle to the surface of the substrate that moves relative to each other in this way, and the resist liquid is applied to almost the entire surface of the substrate.

Patent No. 4571525 Patent No. 5346643

In the coating device configured as described above, after positioning the long nozzle with respect to the stationary substrate, the resist liquid is started to be discharged from the long nozzle, and the substrate is conveyed and the long nozzle is ejected. And the movement of is started. Here, the substrate is conveyed relative to the long nozzle, and the relative moving speed of the substrate is the combined speed of the conveying speed of the substrate and the moving speed of the long nozzle. For example, when the transfer of a stationary substrate is started, the transfer speed of the substrate is accelerated immediately after the start of transfer, reaches the target transfer speed after a certain time from the start of movement, and then the constant speed transfer is performed (described later). (See column (a) of FIG. 7). The long nozzle also moves with the same profile. Therefore, their combined speeds change relatively sharply at the start of movement of the substrate and the long nozzle and at the time of reaching the target movement speed (see column (b) of the figure). On the other hand, the discharge rate of the resist liquid from the long nozzle changes relatively slowly (see column (c) in the figure). Therefore, the profile of the synthesis rate and the profile of the discharge rate may not partially match, and the film thickness of the resist liquid applied to the substrate may become non-uniform.

The present invention has been made in view of the above problems, and is used in a coating technique for applying a coating liquid to a substrate by moving a nozzle for transporting the substrate and discharging a coating liquid from a discharge port in the transport direction of the substrate. The purpose is to make the thickness of the coating liquid applied to the coating uniform.

The first aspect of the present invention is a coating device, which is a nozzle having a discharge port for discharging a coating liquid toward a substrate, a substrate transport portion for transporting the substrate, and nozzle movement for moving the nozzle in the transport direction of the substrate. A pump that discharges the coating liquid from the discharge port of the nozzle to the substrate, and a control that controls the transfer of the substrate by the substrate transport unit, the movement of the nozzle by the nozzle moving unit, and the discharge of the coating liquid from the discharge port by the pump. The control unit accelerates the transfer of the substrate after the start of the transfer of the stationary substrate, and accelerates the movement of the nozzle after the start of the movement of the stationary nozzle to move the substrate relative to the nozzle, and causes the substrate to move relative to the nozzle. to accelerate the discharge of the coating liquid after ejection start of the coating liquid from the substrate at the time by applying a coating solution to a substrate to move relative to the nozzle, the conveying speed of the substrate after the start transfer of the substrate reaches the target conveyance speed When the nozzle movement speed reaches the target movement speed after the nozzle movement starts, the nozzle movement acceleration is stopped, and the discharge speed reaches the target discharge speed after the coating liquid discharge starts. At that point, the acceleration of the coating liquid discharge is stopped, and at least the substrate is transported, the nozzle is moved, and the coating liquid is discharged according to the change characteristics of the discharge speed of the coating liquid discharged from the discharge port at the start of the coating liquid discharge. together to shifting relative to conveyance start timing and the moving start timing of the nozzle of the substrate by adjusting the one, conveying the substrate in accordance with the change characteristic of the discharge speed at the time of acceleration stop the discharge of the coating solution, the movement of the nozzle And by adjusting at least one of the discharges of the coating liquid, the acceleration stop timing of the substrate transfer and the acceleration stop timing of the nozzle movement are relatively shifted, so that the substrate transfer while the substrate transfer is accelerated. A relative movement curve that combines a transport speed curve showing a change in speed and a movement speed curve showing a change in nozzle movement speed while accelerating the movement of the nozzle, and a relative movement curve that shows the change in the nozzle movement while accelerating the discharge of the coating liquid. The feature is that the curve showing the change in the discharge rate of the coating liquid matches the discharge rate curve.

A second aspect of the present invention is a coating method, in which the first step of stopping the nozzle with the nozzle discharge port facing the stationary substrate and the movement of the stationary substrate in the transport direction. to accelerate the movement of the nozzle after the movement start in the transport direction of the nozzle stationary with accelerate transfer of the substrate after the start relatively moving the substrate relative to the nozzle, the transport speed of the substrate after the start of movement of the conveying direction of the substrate The substrate is moved relative to the nozzle so that the movement of the substrate is accelerated until the target transfer speed is reached, and the movement of the nozzle is accelerated until the movement speed of the nozzle reaches the target movement speed after the movement of the nozzle in the transfer direction is started. a second step of Ru is, moved relative to the nozzle to accelerate the discharge of the coating liquid to the discharge rate of the coating liquid from the discharge port after starting the discharge of the coating liquid from the discharge port reaches the target moving velocity The substrate is provided with a third step of applying the coating liquid to the substrate, and in the second step, the substrate is conveyed and the nozzle is transferred according to the change characteristics of the discharge rate of the coating liquid discharged from the discharge port at the start of discharging the coating liquid. movement and with Las not a relative movement start of the conveyance start a nozzle substrate by adjusting at least one of the discharge of the coating solution, the change characteristic of the discharge speed at the time of acceleration stop the discharge of the coating liquid By adjusting at least one of the transfer of the substrate, the movement of the nozzle, and the discharge of the coating liquid accordingly, the transfer of the substrate can be carried out by relatively shifting the acceleration / stop timing of the transfer of the substrate and the acceleration / stop timing of the movement of the nozzle. A relative movement curve that combines a transfer speed curve that shows the change in the transfer speed of the substrate during acceleration and a movement speed curve that shows the change in the movement speed of the nozzle while accelerating the movement of the nozzle, and a coating liquid. It is characterized in that the curve showing the change in the discharge rate of the coating liquid while accelerating the discharge of the coating liquid coincides with the discharge rate curve.

Further, a fourth aspect of the present invention is a coating method, in which the first step of stopping the nozzle with the nozzle discharge port facing the stationary substrate and after the start of movement of the substrate in the transport direction. For the nozzle, the movement of the substrate is accelerated until the transfer speed of the substrate reaches the target transfer speed, and the movement of the nozzle is accelerated until the movement speed of the nozzle reaches the target movement speed after the movement of the nozzle in the transfer direction is started. The coating liquid is applied to the substrate that moves relative to the nozzle by accelerating the discharge of the coating liquid until the discharge speed of the coating liquid from the discharge port reaches the target movement speed in the second step of relatively moving the substrate. The third step is provided, and in the second step, the acceleration stop timing of the substrate transfer and the acceleration stop timing of the nozzle movement are shifted from each other according to the change characteristic of the discharge speed when the discharge of the coating liquid is stopped. It is characterized by that.

In the third aspect and the fourth aspect configured as described above, in the initial stage of the coating process of applying the coating liquid discharged from the ejection port of the nozzle to the substrate, the stationary substrate starts moving in the transport direction. Later, the transfer of the substrate is accelerated until the target transfer speed is reached, and after the movement of the stationary nozzle in the transfer direction is started, the movement of the nozzle is accelerated until the target movement speed is reached. The relative moving speed of the substrate with respect to the nozzle at this time is the combined speed of the conveying speed of the substrate and the moving speed of the nozzle. Then, the coating liquid is applied to the substrate which is moved relative to the nozzle at the synthesis speed. Even in this initial stage, the acceleration of the coating liquid discharge speed from the nozzle is not constant but changes, that is, there is a change characteristic, especially in the vicinity of the acceleration stop of the coating liquid discharge speed. Therefore, in the inventions according to the third aspect and the fourth aspect, the synthesis speed is changed by relatively shifting the acceleration stop timing of the transfer of the substrate and the acceleration stop timing of the nozzle movement according to the change characteristic. The thickness of the coating liquid applied to the substrate is made uniform in the initial stage.

As described above, according to the present invention, in the initial stage of the coating process of applying the coating liquid discharged from the discharge port of the nozzle to the substrate, it corresponds to the change characteristic of the discharge speed of the coating liquid discharged from the discharge port. Timing control is performed. More specifically, the transfer start timing of the substrate and the movement start timing of the nozzle are relatively shifted, and / or the acceleration / stop timing of the transfer of the substrate and the acceleration / stop timing of the movement of the nozzle are relatively shifted. Therefore, in the initial stage, the relative movement speed of the substrate with respect to the nozzle and the discharge speed of the coating liquid can be well matched, and the thickness of the coating liquid applied to the substrate can be made uniform.

It is a figure which shows one Embodiment of the coating apparatus which concerns on this invention. It is a top view which removed the coating mechanism from FIG. 1A. It is a block diagram which shows the control mechanism which controls the coating apparatus shown in FIG. 1A. It is a top view of the levitation mechanism. It is a side view which shows typically the relationship between a levitation mechanism and a coating mechanism. It is a side view of the coating apparatus shown in FIG. 1A. It is a flowchart which shows the coating process executed by the coating apparatus shown in FIG. 1A. It is a figure which shows the positional relationship of each part in each stage during a coating process. It is a figure which shows an example of the operation when the operation start and acceleration stop of a substrate and a nozzle are performed at the same time. It is a figure which shows the operation in the initial stage of the coating process executed by the coating apparatus shown in FIG. It is a figure which shows the operation in the initial stage of the coating process in another embodiment of this invention.

FIG. 1A is a diagram showing an embodiment of the coating apparatus according to the present invention, is a plan view seen from above vertically, and FIG. 1B is a plan view in which the coating mechanism is removed from FIG. 1A. Further, FIG. 2 is a block diagram showing a control mechanism for controlling the coating apparatus shown in FIG. 1A. In addition, in FIGS. 1A, 1B and each drawing described later, in order to clarify the arrangement relationship of each part of the apparatus, the transport direction of the substrate S is set to "X direction", and the left-hand side to the right-hand side of FIGS. 1A and 1B. The horizontal direction toward the side is referred to as "+ X direction", and the opposite 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.

The coating device 1 is a slit coater that receives the rectangular substrate S in a horizontal posture conveyed from the roller conveyor 100 and applies the coating liquid to the surface Sf of the substrate S. In this coating device 1, a transfer mechanism 2 is provided adjacent to the roller conveyor 100. The transfer mechanism 2 receives the substrate S from the roller conveyor 100 and transfers it to the levitation mechanism 3.

The levitation mechanism 3 has three levitation units 3A to 3C. As shown in FIG. 1B, these levitation units 3A to 3C are arranged in the transport direction X of the substrate S. More specifically, the upstream levitation unit 3A is arranged adjacent to the transfer mechanism 2 on the most upstream side, that is, the (-X) direction side, and the downstream levitation unit 3C is arranged on the most downstream side, that is, the (+ X) direction side. ing. Further, the central levitation unit 3B is arranged between the upstream levitation unit 3A and the downstream levitation unit 3C.

FIG. 3A is a plan view of the levitation mechanism, and FIG. 3B is a side view schematically showing the relationship between the levitation mechanism and the coating mechanism. In these drawings, the entire central levitation unit 3B and a part of the upstream levitation unit 3A and the downstream levitation unit 3C are schematically shown.

Both the upstream levitation unit 3A and the downstream levitation unit 3C are formed by dispersing a large number of air ejection holes 31 in a matrix over the entire surface of one plate-shaped stage surface 32. Then, by applying compressed air to each of the ejection holes 31, the substrate S is floated by the gas pressure generated by the ejection of the compressed air from each of the ejection holes 31. As a result, in the upstream levitation unit 3A and the downstream levitation unit 3C, the substrate S floats from the stage surface 32 by a predetermined levitation height, for example, 10 to 500 micrometers. In addition, in order to supply compressed air to each ejection hole 31, for example, the configuration described in Patent Document 2 can be used.

Further, although not shown in FIGS. 3A and 3B, the downstream levitation unit 3C has a plurality of lift pins and a lift pin elevating mechanism in addition to the ejection hole 31. The plurality of lift pins are provided so as to face the entire back surface Sb of the substrate S at predetermined intervals by sewing between the ejection holes 31. Then, the lift pin is lifted and driven in the vertical direction (Z-axis direction) by the lift pin lifting mechanism installed below the stage surface 32. That is, when descending, the tip of the lift pin descends toward the (-Z) direction of the stage surface 32 of the downstream levitation unit 3C, and when ascending, the tip of the lift pin delivers the substrate S to the transfer robot (not shown). Ascend to. Since the lower surface of the substrate S is supported and lifted by the lift pin thus raised, the substrate S rises from the stage surface 32 of the downstream levitation unit 3C. This enables the transfer robot to unload the substrate S from the coating device 1.

On the other hand, the central levitation unit 3B is configured as follows and has higher levitation accuracy than the upstream levitation unit 3A and the downstream levitation unit 3C. That is, the central levitation unit 3B has a rectangular plate-shaped stage surface 33. The stage surface 33 is provided with a plurality of holes dispersed in a matrix at a pitch narrower than that of the ejection holes 31 provided in the upstream levitation unit 3A and the downstream levitation unit 3C. Further, unlike the upstream levitation unit 3A and the downstream levitation unit 3C, in the central levitation unit 3B, half of the holes function as compressed air ejection holes 34a, and the other half function as suction holes 34b. That is, the compressed air is ejected from the ejection hole 34a toward the back surface Sb of the substrate S, and the compressed air is sent into the space SP (FIG. 3B) between the stage surface 33 and the back surface Sb of the substrate S. On the other hand, it is configured to suck air from the space SP through the suction hole 34b. By ejecting and sucking air into the space SP in this way, in the space SP, the air flow of the compressed air ejected from each ejection hole 34a spreads in the horizontal direction, and then the ejection hole 34a The pressure balance in the air layer (pressure gas layer) spreading in the space SP becomes more stable, and the floating height of the substrate S is made highly accurate and stable. Can be controlled. In addition, in order to supply compressed air to each ejection hole 34a and suck air from the suction hole 34b, for example, the configuration described in Patent Document 2 can be used.

Further, when the arrangement structure of the ejection hole 34a and the suction hole 34b is viewed from another angle as described above, it can be defined as having the following structure. That is, the central levitation unit 3B has two types of levitation rows 35a and 35b that stably levate a part of the substrate S in a strip shape extending in the horizontal direction Y orthogonal to the transport direction X of the substrate S. .. In the levitation row 35a, the ejection holes 34a, the suction holes 34b, the ejection holes 34a, ..., The suction holes 34b and the ejection holes 34a are arranged in this order in the Y direction. On the other hand, in the levitation row 35b, the suction holes 34b, the ejection holes 34a, the suction holes 34b, ..., The ejection holes 34a and the suction holes 34b are arranged in this order in the Y direction. The central levitation unit 3B is formed by arranging these levitation rows 35a and 35b alternately in the X direction. Since the Y-direction size of each of the levitation rows 35a and 35b is the same as or slightly wider than the Y-direction size of the substrate S, the substrate S can be stably levitated in the Y-direction. On the other hand, since the X-direction size of each of the levitation rows 35a and 35b is significantly smaller than the X-direction size of the substrate S, it is difficult to stably levitate the substrate S in the X-direction by itself. Therefore, the region in which the substrate S is stably levitated in the X direction is the central region of the central levitation unit 3B. Therefore, in the present embodiment, as will be described later, the range in which the slit nozzle 511 is moved in the X direction (hereinafter referred to as “nozzle moving range”) is limited to the central region of the central levitation unit 3B. More specifically, as shown by the broken line in FIG. 3A, the nozzle sandwiched between the second levitation row 35a counting from the (-X) side and the second levitation row 35b counting from the (+ X) side. The slit nozzle 511 is movable within the moving range.

In the coating device 1, a transport mechanism 4 is provided in order to intermittently transport the substrate S in a state of being levitated by the levitation units 3A to 3C in the transport direction X. Hereinafter, the configuration of the transport mechanism 4 will be described with reference to FIGS. 1A, 1B, 3B, and 4.

FIG. 4 is a side view of the coating apparatus shown in FIG. 1A. The transport mechanism 4 has a function of sucking and holding both end portions of the substrate S supported by the levitation mechanism 3 in the Y direction in the Y direction while transporting the substrate S in the transport direction X while being levitated by the levitation mechanism 3. have. As shown in FIG. 1B, the transport mechanism 4 includes a plurality of chuck portions 41 that attract and hold the substrate S. Here, two chuck members 41a are arranged in the X direction, and one chuck portion 41 that can be integrally moved in the X direction is provided on the (+ Y) side and one on the (−Y) direction side, for a total of two. However, each chuck member 41a may be provided as a chuck portion 41. In the present embodiment, the two chuck portions 41 described above have a symmetrical structure (symmetrical on the + Y side and the −Y side), and the substrate S is adsorbed and held on each of the left and right sides. Further, the transport mechanism 4 includes a transport chuck traveling guide 42, a transport chuck linear motor 43, a transport chuck linear scale 44, and a chuck elevating cylinder 45. The chuck portion 41 can be raised and lowered by the operation of the chuck raising and lowering cylinder 45. Therefore, when the chuck elevating cylinder 45 operates in response to the holding command from the control unit 9 (FIG. 2) that controls the entire device, the chuck unit 41 rises to the (+ Y) side and the (−Y) side. The lower surfaces of both ends of the substrate S are supported and sucked and held. Further, the transport chuck traveling guide 42 extends in the X direction on the base 10 of the coating device 1, and the transport chuck linear motor 43 operates in response to a transport command from the control unit 9, so that the chuck portion 41 Is reciprocated in the transport direction X along the transport chuck travel guide 42. As a result, the substrate S held by the chuck portion 41 is transported in the transport direction X. In this embodiment, the position of the substrate S in the transport direction X can be detected by the transport chuck linear scale 44, and the control unit 9 sets the transport chuck linear motor 43 based on the detection result of the transport chuck linear scale 44. Drive control.

The substrate S is transported in the transport direction X in a so-called face-up state in which the surface Sf is directed vertically upward by the transport mechanism 4 described above. A coating mechanism 5 is provided. The coating mechanism 5 includes a nozzle unit 51 that can move in the transport direction X with respect to the base 10, and a nozzle fixed to the base 10 on the upstream side (left hand side in FIG. 1A) of the nozzle unit 51 in the transport direction X. It has a cleaning standby unit 52, a coating liquid supply unit 58 that supplies the coating liquid to the nozzle unit 51, and a coating liquid replenishment unit 59.

As shown in FIG. 4, the nozzle unit 51 includes a slit nozzle 511 extending in the Y direction facing the surface Sf of the substrate S, a nozzle support member 512 that supports the slit nozzle 511, and a transfer mechanism in the Y direction. It is provided with an elevating portion 513 having a symmetrical structure (symmetrical on the + Y side and the −Y side) provided on the outer side of No. 4. In this embodiment, the pair of elevating portions 513 is configured to elevate the slit nozzle 511 in the vertical direction Z via the nozzle support member 512. More specifically, each elevating part 513 includes a columnar member 514, a ball screw 515 attached to the columnar member 514 in a state of extending parallel to the vertical direction Z, and a rotary motor 516 connected to the upper end of the ball screw 515. It is provided with a bracket 517 screwed into a ball screw 515. Then, when the rotation motor 516 is operated in response to the rotation command from the control unit 9, the ball screw 515 rotates, and the bracket 517 moves up and down in the vertical direction Z according to the amount of rotation. Both ends of the nozzle support member 512 are attached to the brackets 517 on the (+ Y) direction side and the (-Y) direction side configured in this way, and are supported so as to be able to move up and down via the nozzle support member 512. ..

Further, as shown in FIG. 4, each elevating portion 513 is reciprocated in the transport direction X by the moving mechanism 518 of the coating mechanism 5. As shown in FIG. 4, the moving mechanism 518 includes a base portion 518a that supports the elevating portion 513 from below, a traveling guide 518b, and a linear motor 518c. As shown in FIGS. 1A and 1B, the traveling guide 518b extends in the X direction on the base 10 of the coating device 1, and the linear motor 518c operates in response to a movement command from the control unit 9. The elevating part 513 is reciprocated in the transport direction X along the traveling guide 518b, and the slit nozzle 511 can be positioned at the maintenance position and the discharge position together with the elevating part 513. Here, the "maintenance position" means a position where the nozzle cleaning standby unit 52 performs a maintenance operation including preliminary discharge, and the "discharge position" is a position where the coating liquid is discharged toward the substrate S, that is, It means the position directly above the central levitation unit 3B.

A slit nozzle 511 is attached to the lower end of the nozzle support member 512 with the discharge port 511a facing downward. Therefore, the slit nozzle 511 can be raised and lowered by the control of the rotary motor 516 by the control unit 9, and the discharge port 511a can be brought close to the surface Sf of the substrate S conveyed by the conveying mechanism 4, or conversely separated upward. It has become. Further, the control unit 9 controls the rotary motor 516 based on the output of the levitation height detection sensor (reference numeral 53 in FIG. 3B), which will be described later, thereby reducing the distance between the surface Sf of the substrate S and the discharge port 511a. It can be adjusted with high precision. Then, when the coating liquid is pressure-fed from the coating liquid supply unit 58 to the slit nozzle 511 with the discharge port 511a close to the surface Sf of the substrate S, the coating liquid is discharged from the discharge port 511a toward the surface Sf of the substrate S. .. The slit nozzle 511 includes a protective member for protecting the tip of the nozzle (reference numeral 6B1 in FIG. 3B), a levitation height detection sensor (reference numeral 53 in FIG. 3B), and a vibration sensor (reference numeral 6B2 in FIG. 3B). Is installed.

As shown in FIG. 4, the coating liquid supply unit 58 uses a pump 581, such as a tube pump or a bellows pump, for pumping the coating liquid to the slit nozzle 511 to feed the coating liquid by changing the volume. I am using it. One end of the pipe 582 is connected to the output side of the pump 581. Further, the other end of the pipe 582 is branched into two, and as shown in FIG. 4, one of the pipes 583 is connected to the end of the slit nozzle 511 on the (-Y) direction side, and the other end is connected. The pipe 584 is connected to the end of the slit nozzle 511 on the (+ Y) direction side. On-off valves 585 and 586 are inserted in these pipes 583 and 584, respectively, and open and close in response to an open / close command from the control unit 9, whereby the coating liquid is sent to the slit nozzle 511 and the liquid is sent. It is possible to switch the stop.

Further, the supply of the coating liquid to the slit nozzle 511 reduces the ratio of the coating liquid filled in the pump 581, that is, the pump filling rate. Therefore, a coating liquid replenishment unit 59 is provided. As shown in FIG. 3B, the coating liquid replenishment unit 59 includes a storage tank 591 for storing the coating liquid, a pipe 592 for connecting the storage tank 591 to the pump 581, and an on-off valve 593 inserted in the pipe 592. It has. The on-off valve 593 is opened from the control unit 9 in response to a replenishment command so that the coating liquid in the storage tank 591 can be replenished to the pump 581. On the contrary, the control unit 9 closes in response to the replenishment stop command to regulate the replenishment of the coating liquid from the storage tank 591 to the pump 581. In the present embodiment, not only the on-off valve 593 described above but also the on-off valves 585 and 586 of the coating liquid supply unit 58 are controlled to open and close, and the coating liquid is replenished. That is, the on-off valve 593 is closed while the replenishment operation is not performed, and the inflow of the coating liquid from the storage tank 591 to the pump 581 is restricted. On the other hand, while the on-off valve 585 and 586 are closed, the pump 581 is operated with the on-off valve 593 opened, so that the coating liquid in the storage tank 591 is drawn into the pump 581 and filled.

The nozzle cleaning standby unit 52 is a device that cleans and removes the coating liquid from the tip of the slit nozzle 511 that has supplied the coating liquid to the surface Sf of the substrate S. It is prepared in a state suitable for the coating process of. As shown in FIGS. 3B and 4, the nozzle cleaning standby unit 52 is mainly composed of a roller 521, a cleaning unit 522, a roller butt 523, and the like, and includes a cleaning standby unit 524 that performs nozzle cleaning and preliminary ejection. .. In the cleaning standby unit 524, the discharge port 511a of the slit nozzle 511 is cleaned after the coating process is performed. Further, when a constant coating liquid is discharged from the discharge port 511a with the slit nozzle 511 close to the outer peripheral surface of the roller 521, a pool of coating liquid is formed in the discharge port 511a (preliminary discharge operation). When the liquid pool is uniformly formed in the discharge port 511a in this way, the subsequent coating process can be performed with high accuracy. In this way, the discharge port 511a of the slit nozzle 511 is initialized to prepare for the next coating process. The rotation of the roller 521 is performed by driving a roller rotation motor (not shown) in response to a rotation command from the control unit 9. Further, the coating liquid adhering to the roller 521 is removed by immersing the lower end in the cleaning liquid stored in the roller bat 523 when the roller 521 rotates.

As described above, in the present embodiment, the slit nozzle 511 is brought close to the surface Sf of the substrate S to perform the coating process. Therefore, if a foreign substance is present on the surface Sf, the slit nozzle 511 collides with the foreign substance and the slit nozzle 511. May be damaged. Further, if an error occurs in the position of the slit nozzle 511 due to the collision, the subsequent coating process cannot be continued. Therefore, in the present embodiment, two types of foreign matter detecting mechanisms 6A and 6B are provided in order to detect foreign matter existing on the surface Sf of the substrate S.

The foreign matter detecting mechanism 6A detects the foreign matter in a non-contact manner on the upstream side of the slit nozzle 511 provided in the coating mechanism in the transport direction X, and has a light emitting unit 6A1 and a light receiving unit 6A2. As shown in FIG. 1B, the light emitting unit 6A1 and the light receiving unit 6A2 are arranged so as to sandwich the central levitation unit 3B from the outside in the Y direction. The light projecting unit 6A1 and the light receiving unit 6A2 are attached to the upper ends of support members (not shown) erected in the vertical direction Z from the upper surface of the base 10, respectively, and the height positions of the light emitting unit 6A1 and the light receiving unit 6A2 are set. It has been adjusted. More specifically, as shown in FIG. 3B, the light emitting unit 6A1 and the light receiving unit so that the laser light emitted from the light emitting unit 6A1 passes over the surface Sf of the substrate S and is incident on the light receiving unit 6A2. 6A2 is arranged. Then, the light emitting unit 6A1 irradiates the laser light toward the light receiving unit 6A2. On the other hand, the light receiving unit 6A2 receives the laser light emitted from the light projecting unit 6A1, measures the amount of the received light, and outputs it to the control unit 9. Then, the control unit 9 detects foreign matter based on the amount of received light.

The other foreign matter detecting mechanism 6B detects the foreign matter by a contact method, and is attached to the slit nozzle 511 of the coating mechanism 5 in the present embodiment. The foreign matter detecting mechanism 6B has a protective member 6B1 attached to the slit nozzle 511 on the upstream side of the discharge port 511a in the transport direction X, and a vibration sensor 6B2 for detecting the vibration of the slit nozzle 511. The protective member 6B1 is a plate member extended in the horizontal direction Y in order to protect the nozzle tip of the slit nozzle 511, and the plate surface is arranged so as to be orthogonal to the surface Sf of the substrate S. Therefore, when a foreign substance is present on the substrate S when the substrate S is conveyed directly below the nozzle unit 51, the protective member 6B1 is a slit nozzle 511 due to contact between the nozzle tip of the slit nozzle 511 and the foreign substance. Suppress damage. Further, when a foreign substance is present, the protective member 6B1 comes into contact with the foreign substance, and vibration is generated in the protective member 6B1 and transmitted to the slit nozzle 511. The vibration sensor 6B2 detects this vibration and outputs it to the control unit 9. Then, the control unit 9 detects foreign matter based on the vibration. In addition to the foreign matter detection mechanism 6B, the slit nozzle 511 has a levitation height for non-contact detection of the levitation height of the substrate S at a position where it enters the upper region of the substrate S before the protective member 6B1. A detection sensor 53 is installed. With this levitation height detection sensor 53, it is possible to measure the separation distance between the levitation substrate S and the upper surface of the stage surface 33 of the central levitation unit 3B, and according to the detected value, via the control unit 9. Therefore, the position where the slit nozzle 511 is lowered can be adjusted. As the levitation height detection sensor 53, an optical sensor, an ultrasonic sensor, or the like can be used.

As described above, in the present embodiment, the foreign matter can be reliably detected by providing the two types of foreign matter detecting mechanisms 6A and 6B. Moreover, when the foreign matter is detected, the control unit 9 forcibly stops the transport of the substrate S to prevent the slit nozzle 511 from being damaged or the substrate S from being damaged.

The control unit 9 has a function of controlling each unit of the coating device 1 as described above. The control unit 9 has a CPU 91 that executes a predetermined processing program to control the operation of each unit, and a memory 92 for storing and storing the processing program executed by the CPU 91 and the data generated during the processing. And a display unit 93 for notifying the user of the progress of processing, detection of foreign matter, and the like as needed. Then, in the coating device 1, the coating process is executed by the CPU 91 controlling each part of the device according to the processing program as follows.

FIG. 5 is a flowchart showing a coating process executed by the coating apparatus shown in FIG. 1A. Further, FIGS. 6A to 6D are diagrams showing the positional relationship of each part at each stage during the coating process. In the coating process shown in FIG. 5, after receiving the untreated substrate S from the roller conveyor 100, the coating liquid is discharged from the slit nozzle 511 to the surface Sf of the substrate S while floating and transporting the substrate S in the (+ X) direction. To form a coating layer. This coating process is performed by the CPU 91 executing a processing program stored in advance to control each part.

When a coating command is given to the control unit 9, the transfer mechanism 2 receives the substrate S from the roller conveyor 100 and transfers it to the levitation unit 3A (step S101). Further, the control unit 9 has various information related to the coating process included in the coating command, that is, coating conditions such as change characteristics of the ejection speed of the coating liquid discharged from the discharge port 511a, a substrate target speed, a nozzle target speed, and a coating liquid thickness. Is obtained, and the transfer timing of the substrate S and the movement timing of the slit nozzle 511 are calculated based on them (step S102). This is because, in the present embodiment, as will be described in detail later, in the initial stage of the coating process, uniform formation of the coating film is performed by timing control according to the change characteristic of the discharge rate of the coating liquid discharged from the discharge port 511a. To do.

In the next step S103, the nozzle cleaning standby unit 52 executes the preliminary discharge. This preliminary discharge is an operation of discharging a constant coating liquid from the discharge port 511a with the slit nozzle 511 close to the outer peripheral surface of the roller 521, whereby the coating liquid is applied to the discharge port 511a as shown in FIG. 6A. A puddle LD of liquid is formed. When the liquid pool LD is uniformly formed in the discharge port 511a in this way, the subsequent coating process can be performed with high accuracy. In this way, the discharge port 511a of the slit nozzle 511 is initialized, and the preparation for the next coating process is completed.

Following this, the elevating unit 513 and the moving mechanism 518 operate in response to the movement command from the control unit 9, move the slit nozzle 511 to the coating start position PS, and direct the discharge port 511a (FIG. 3B) vertically downward. And statically position (step S104). Further, at the same time as or before and after the movement of the slit nozzle 511, the transport mechanism 4 transports the substrate S in the (+ X) direction in response to a transport command from the control unit 9, and the surface Sf of the substrate S is applied first. When the region to be powered is located at the coating start position PS, the substrate transfer is stopped and stopped (step S105). In this way, as shown in FIG. 6B, when both the slit nozzle 511 and the substrate S are positioned at the coating start position PS, the coating process is executed as shown in FIGS. 5 and 6B to 6D (step S106). ). Further, in parallel with the coating process, the transfer mechanism 2 receives the next substrate S from the roller conveyor 100 and transfers it to the levitation unit 3A (step S107) to prepare for the next coating process.

Immediately before the start of the coating process, as shown in FIG. 6B, the discharge port 511a of the slit nozzle 511 and the (+ X) side end of the substrate S are stationary at the coating start position PS (that is, both the substrate transport speed and the nozzle moving speed are both. Zero), the slit nozzle 511 is located directly above the surface Sf of the substrate S. Further, the slit nozzle 511 is brought close to the substrate S by the elevating portion 513. In this way, with the discharge port 511a close to each other, the control unit 9 controls the coating liquid supply unit 58 to pump a constant amount of coating liquid to the slit nozzle 511 for a certain period of time to bead B (liquid on the substrate S). Puddle) is formed.

Then, the substrate S is conveyed in the (+ X) direction, the slit nozzle 511 is moved in the (−X) direction, and the coating liquid is discharged from the discharge port 511a. That is, when the transfer of the stationary substrate S is started, the transfer of the substrate S is accelerated until the target transfer speed (see FIGS. 7 and 8) is reached, and after the target transfer speed is maintained for a certain period of time. The speed is reduced, and the (−X) side end portion of the substrate S is stopped at the coating end position PE. Further, when the movement of the slit nozzle 511 that had been stationary was started, the movement of the slit nozzle 511 was accelerated until the target movement speed (see FIGS. 7 and 8) was reached, and the nozzle target speed was maintained for a certain period of time. The speed is reduced later, and the discharge port 511a of the slit nozzle 511 is stopped at the coating end position PE. In this way, while the substrate S moves relative to the slit nozzle 511, the coating liquid is started to be discharged from the discharge port 511a and accelerated until the discharge speed reaches the target discharge speed (see FIGS. 7 and 8). After maintaining the target discharge speed for a certain period of time, the speed is reduced and the discharge of the coating liquid is stopped. In this way, the coating process of applying the coating liquid layer having the desired thickness, that is, the coating layer CL to the surface of the substrate S is executed. Especially in the initial stage of the coating process, the substrate S is formed at the timing calculated in step S102. Conveyance and movement of the slit nozzle 511 are performed. This point will be described in detail later with reference to FIGS. 7 and 8.

When the above coating process (step S106) is completed, as shown in FIG. 6D, the last region to be coated and the slit nozzle 511 of the surface Sf of the substrate S are located at the coating end position PE. After that, the slit nozzle 511 is moved from the coating end position PE toward the nozzle cleaning standby unit 52 (step S108). On the other hand, the substrate S coated with the coating liquid is carried out as follows (step S109). That is, the substrate S is lifted by a lift pin (not shown) after being conveyed to the downstream levitation unit 3C, and is lifted from the stage surface 32 of the downstream levitation unit 3C. Further, the substrate S is carried out from the coating device 1 by a transfer robot (not shown).

Here, when the next unprocessed substrate S is transferred to the levitation unit 3A by the transfer mechanism 2 and is on standby (“YES” in step S110), the coating condition for the standby substrate S is the previous time. After confirming in step S111 whether or not the coating conditions are changed from the above, the above series of processes are repeated. That is, when the coating conditions are changed (“YES” in step S111), the process returns to step S102, while when the application conditions are not changed (“NO” in step S111), the process returns to step S103 and the above process is repeated.

Next, the initial stage of the coating process will be described with reference to FIGS. 7 and 8. The "initial stage of the coating process" in the present specification means a period from the start of discharging the coating liquid from the discharge port 511a to the discharge speed of the coating liquid reaching the target discharge speed. FIG. 7 is a diagram showing an example of the operation when the operation of the substrate and the slit nozzle is started and accelerated at the same time in the initial stage of the coating process. On the other hand, FIG. 8 is a diagram showing an operation in the initial stage of the coating process executed by the coating apparatus shown in FIG. 1, and is a diagram showing an example of the operation when the movement start and acceleration stop of the substrate and the nozzle are different. is there. In both FIGS. 7 and 8, the following profiles are illustrated in columns (a) to (c). That is, in column (a), the change in the transfer speed of the substrate S, that is, the change in the transfer speed curve (dashed line) and the change in the movement speed of the slit nozzle 511, that is, the movement speed curve (solid line) are shown. Further, in column (b), the change in the combined speed of the transport speed of the substrate S and the movement speed of the slit nozzle 511 (that is, the relative movement speed of the substrate S with respect to the slit nozzle 511) is shown as a relative movement curve (broken line). .. Further, in column (c), a change in the discharge speed of the coating liquid discharged from the discharge port 511a of the slit nozzle 511, that is, a discharge speed curve (solid line) and the relative movement curve are shown. When these discharge rate curves and relative movement curves partially deviate from each other, the thickness of the coating layer CL (see FIGS. 6C and 6D) becomes non-uniform. On the other hand, when the discharge rate curve and the relative movement curve are approximated, the coating layer CL can be formed with a uniform thickness.

Reference numerals “Ts1” and “Ts2” in FIGS. 7 and 8 indicate the transfer start timing of the substrate S and the acceleration / stop timing of the transfer of the substrate S, respectively, and the reference numerals “Tn1” and “Tn2” indicate the movement of the slit nozzle 511, respectively. The start timing and the acceleration / stop timing of the movement of the slit nozzle 511 are shown. In the conventional device, as shown in the column (a) of FIG. 7, the substrate S is conveyed and the slit nozzle 511 is moved at the same time. Therefore, as shown in the column (b) of FIG. 7, the combined speed of the transport speed of the substrate S and the moving speed of the slit nozzle 511 changes relatively sharply at the timings Ts1 (Tn1) and Ts2 (Tn2). On the other hand, the discharge rate of the coating liquid changes relatively slowly as shown in the column (c) of FIG. As a result, the discharge rate curve and the relative movement curve do not partially match between the discharge start time and the time when the target discharge speed is reached, and the thickness of the coating layer CL becomes non-uniform.

Therefore, in the present embodiment, as shown in FIG. 8, the transfer start timing Ts1 of the substrate S and the movement start timing Tn1 of the slit nozzle 511 are set according to the change characteristic of the discharge rate of the coating liquid at the discharge start time of the coating liquid. It is relatively shifted. More specifically, since the movement acceleration of the slit nozzle 511 is smaller than the transfer acceleration of the substrate S, that is, the movement speed curve rises more slowly than the transfer speed curve, the movement start timing Tn1 is set from the transfer start timing Ts1. Is relatively early.

On the other hand, the acceleration stop timing Ts2 of the transfer of the substrate S and the acceleration stop timing Tn2 of the movement of the slit nozzle 511 are relative to each other according to the change characteristic of the discharge rate of the coating liquid in the vicinity where the discharge speed of the coating liquid reaches the target discharge speed. The target is shifted. More specifically, for the same reason as described above, the acceleration stop timing Tn2 is set to be relatively later than the acceleration stop timing Ts2.

In order to perform such timing control, in the present embodiment, the control unit 9 calculates the transfer timing of the substrate S and the movement timing of the slit nozzle 511 in step S102, and transfers the substrate S and the slit nozzle 511 at those timings. Is moving. As a result, the change in the combined speed at the time when the coating liquid is started to be discharged and when the discharge speed reaches the target discharge speed becomes gradual, and the relative movement speed of the substrate S with respect to the slit nozzle 511 (the above-mentioned combined speed) is the discharge speed curve. Approximate to. As a result, the coating layer CL formed in the initial stage of the coating treatment can be formed with a uniform thickness.

As described above, in the present embodiment, the transfer start timing Ts1 of the substrate S and the movement start timing Tn1 of the slit nozzle 511 are relatively shifted according to the change characteristic of the discharge rate (profile of the discharge rate curve), and the synthesis speed is combined. Is adapted to the above change characteristics. Further, the acceleration / stop timing Ts2 of the transfer of the substrate S and the acceleration / stop timing Tn2 of the movement of the slit nozzle 511 are relatively shifted according to the change characteristics to match the synthesis speed with the change characteristics. Further, from the transfer start timing Ts1 to the acceleration stop timing Ts2, as shown in FIG. 8, the transfer speed and the moving speed are set so that the combined speed matches the discharge speed. Therefore, the change in the relative moving speed (the combined speed) of the substrate S with respect to the slit nozzle 511 approximates the discharge speed curve over the entire initial stage of the coating process. As a result, the coating layer CL formed at the initial stage of the coating treatment can be formed with a uniform thickness.

Further, after the discharge speed reaches the target discharge speed, the transport speed and the moving speed are set so that the combined speed matches the discharge speed. Therefore, the coating layer CL can be formed with a uniform thickness not only in the initial stage of the coating treatment but also in the entire coating treatment.

As described above, in the present embodiment, the transport mechanism 4 and the moving mechanism 518 correspond to an example of the "board transport portion" and the "nozzle moving portion" of the present invention, respectively.

By the way, as the film thickness of the coating layer CL increases, the timing is such that the amount of deviation ΔT1 between the transfer start timing Ts1 and the movement start timing Tn1 and the amount of deviation ΔT2 between the acceleration stop timing Ts2 and the acceleration stop timing Tn2 increase. It is desirable to control. The reason for this will be described below with reference to FIG.

FIG. 9 is a diagram showing an operation in an initial stage of a coating process according to another embodiment of the present invention. As shown in the figure, when the film thickness of the coating layer CL is relatively thin (film thickness t1), the discharging speed of the coating liquid is changed according to the profile shown by the discharge rate curve (dashed line) in the figure. Just do it. Here, when the target discharge speed is increased from the target discharge speed (t1) to the target discharge speed (t2) in order to form the coating layer CL having a relatively thick film thickness t2, the solid line in the column (a) of FIG. 8 shows. As shown, overshoot occurs when the discharge rate reaches the target discharge rate (t2), which causes non-uniformity of the film thickness. Therefore, in order to prevent the occurrence of overshoot, it is necessary to suppress the discharge acceleration of the coating liquid according to the increase in the film thickness, as shown by the solid line in the column (b) of FIG. As a result, the change in the discharge speed at the time of starting the discharge and at the time of reaching the target discharge speed becomes more gradual. In order to deal with this, it is necessary to set a large amount of deviation.

In order to form such a uniform coating layer CL, it is necessary to set an appropriate amount of deviation according to the film thickness. Therefore, for example, the correlation between the film thickness and the amount of deviation may be acquired in advance by an experiment or simulation, and the timing may be controlled based on the correlation.

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 timing control of shifting the transfer start timing Ts1 and the movement start timing Tn1 and the timing control of shifting the acceleration stop timing Ts2 and the acceleration stop timing Tn2 are performed. The same effect can be obtained when only the method is performed.

Further, in the above embodiment, the relative movement curve showing the change in the combined speed is approximated to the discharge speed curve by the timing control, but the discharge speed curve matches the relative movement curve by further controlling the discharge of the coating liquid. It may be configured to do so. Further, in order to make the discharge speed curve and the relative movement curve more highly matched, in addition to the above timing control, the transfer of the substrate S and the movement of the slit nozzle 511 may be controlled.

Further, in the above embodiment, the transfer of the substrate S is started after the movement of the slit nozzle 511 is started, but the movement mode of the slit nozzle 511 and the transfer mode of the substrate S are not limited to this. Absent. Further, the present invention is applied to the coating apparatus 1 in which the coating liquid is applied to the surface of the substrate S as a treatment liquid while the substrate S is floated and conveyed, but the application target of the present invention is limited to this. It's not a thing. In short, it can be applied to all coating devices that transport the substrate S and move the slit nozzle 511 in the transport direction X of the substrate S.

The present invention can be applied to all coating techniques for applying a coating liquid to a substrate by moving a nozzle that conveys the substrate and discharges the coating liquid from a discharge port in the transport direction of the substrate.

1 ... Coating device 4 ... Transfer mechanism (board transfer part)
5 ... Coating mechanism 9 ... Control unit 51 ... Nozzle unit 511 ... Slit nozzle 511a ... Discharge port 518 ... Moving mechanism (nozzle moving part)
S ... Substrate Tn1 ... (Slit nozzle) movement start timing Tn2 ... (Slit nozzle movement) acceleration stop timing Ts1 ... (Board) transfer start timing Ts2 ... (Substrate transfer) acceleration stop timing X ... Transfer direction ΔT1 … Amount of deviation (between transfer start timing and movement start timing) ΔT2… Amount of deviation (of acceleration stop timing)

Claims (4)

A nozzle having a discharge port for discharging the coating liquid toward the substrate,
A substrate transporting unit that transports the substrate and
A nozzle moving portion that moves the nozzle in the transport direction of the substrate, and a nozzle moving portion.
A pump that discharges the coating liquid from the discharge port of the nozzle toward the substrate, and
A control unit for controlling the transfer of the substrate by the substrate transfer unit, the movement of the nozzle by the nozzle moving unit, and the discharge of the coating liquid from the discharge port by the pump is provided.
The control unit
After the transfer of the stationary substrate is started, the transfer of the substrate is accelerated, and after the movement of the stationary nozzle is started, the movement of the nozzle is accelerated to move the substrate relative to the nozzle.
After the start of discharging the coating liquid from the discharge port, the coating liquid is applied to the substrate which accelerates the discharge of the coating liquid and moves relative to the nozzle.
When the transfer speed of the substrate reaches the target transfer speed after the transfer of the substrate is started, the acceleration of the transfer of the substrate is stopped.
When the movement speed of the nozzle reaches the target movement speed after the movement of the nozzle is started, the acceleration of the movement of the nozzle is stopped.
When the discharge speed reaches the target discharge speed after the start of discharge of the coating liquid, the acceleration of the discharge of the coating liquid is stopped.
At least one of the transfer of the substrate, the movement of the nozzle, and the discharge of the coating liquid is adjusted according to the change characteristic of the discharge speed of the coating liquid discharged from the discharge port at the start of discharging the coating liquid. together to shifting relatively in moving start timing of the transfer start timing and said nozzle of said substrate,
Acceleration stop of the transfer of the substrate by adjusting at least one of the transfer of the substrate, the movement of the nozzle, and the discharge of the coating liquid according to the change characteristic of the discharge rate when the discharge of the coating liquid is stopped. By relatively shifting the timing and the acceleration / stop timing of the movement of the nozzle.
A transfer speed curve showing a change in the transfer speed of the substrate while accelerating the transfer of the substrate and a movement speed curve showing a change in the movement speed of the nozzle while accelerating the movement of the nozzle are combined. The coating apparatus is characterized in that the relative movement curve is made to match the discharge speed curve with a curve showing a change in the discharge speed of the coating liquid while accelerating the discharge of the coating liquid. The coating device according to claim 1.
The control unit is a coating device that increases the amount of deviation between the transfer start timing of the substrate and the movement start timing of the nozzle as the thickness of the coating liquid applied to the substrate increases. The coating device according to claim 1 or 2.
The control unit is a coating device that increases the amount of deviation between the acceleration stop timing of the transfer of the substrate and the acceleration stop timing of the movement of the nozzle as the thickness of the coating liquid applied to the substrate increases. The first step of stopping the nozzle with the nozzle discharge port facing the stationary substrate, and
After the stationary movement of the substrate in the transport direction is started, the transport of the substrate is accelerated, and after the stationary nozzle starts to move in the transport direction, the movement of the nozzle is accelerated to move the substrate relative to the nozzle. Then , the transfer of the substrate is accelerated until the transfer speed of the substrate reaches the target transfer speed after the start of movement of the substrate in the transfer direction, and the movement speed of the nozzle is the target after the start of movement of the nozzle in the transfer direction. a second step of Ru by relatively moving the substrate relative to the nozzle as the movement of the nozzle is accelerated to reach the moving speed,
After starting the discharge of the coating liquid from the discharge port, the substrate that accelerates the discharge of the coating liquid and moves relative to the nozzle until the discharge speed of the coating liquid from the discharge port reaches the target moving speed. The third step of applying the coating liquid to the coating liquid is provided.
In the second step,
At the start of discharging the coating liquid, at least one of the transfer of the substrate, the movement of the nozzle, and the discharge of the coating liquid is adjusted according to the change characteristic of the discharge speed of the coating liquid discharged from the discharge port. with relatively not a las movement start of the conveyance start with the nozzle of the substrate in,
Acceleration stop of the transfer of the substrate by adjusting at least one of the transfer of the substrate, the movement of the nozzle, and the discharge of the coating liquid according to the change characteristic of the discharge rate when the discharge of the coating liquid is stopped. By relatively shifting the timing and the acceleration / stop timing of the movement of the nozzle.
A transfer speed curve showing a change in the transfer speed of the substrate while accelerating the transfer of the substrate and a movement speed curve showing a change in the movement speed of the nozzle while accelerating the movement of the nozzle are combined. The coating method is characterized in that the relative movement curve obtained and the curve showing the change in the discharge speed of the coating liquid while accelerating the discharge of the coating liquid coincide with the discharge speed curve. ..

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