JP7500992B2 - Coating device and coating method - Google Patents

Description

The present invention relates to a coating device and coating method for coating a substrate with a liquid.

For example, in the semiconductor manufacturing process, a liquid functional material (hereinafter simply referred to as "liquid") is applied to a semiconductor wafer. Spin coating is known as a technique for applying liquid to a semiconductor wafer. However, in the case of spin coating, the liquid is used inefficiently.
In recent years, a coating device equipped with a coater has been used as a device for coating a liquid on a substrate such as a semiconductor wafer. The coater has a long slit in one direction, and the opening of the slit serves as a liquid discharge port. While the coater and the semiconductor wafer are moved relative to each other, the liquid is discharged from the discharge port to form a coating film on the semiconductor wafer. Patent Document 1 discloses a coating device equipped with a coater.

JP 2017-148769 A

In a coating apparatus equipped with the above-mentioned applicator, the film thickness precision of the applied liquid is likely to decrease at the start (one end) and end (other end) of the coating on the semiconductor wafer.
Here, the coating area on the semiconductor wafer includes an effective area A1 where high film thickness accuracy is required to form components such as chips, and an excluded area A2 around it (the periphery of the semiconductor wafer), as shown in Fig. 9. In the case of the coating device, film thickness accuracy is likely to decrease between one end Wa of the substrate W where coating starts and the other end Wb where coating ends, but it is desirable to coat the liquid so that such one end Wa and other end Wb fall within the range of the excluded area A2.

Figures 10A, 10B, 10C, and 11 are diagrams illustrating a coating method using a coating device equipped with an applicator 90. As shown in Figure 10A, the applicator 90 is moved onto one end Wa of the substrate W, bringing the one end Wa close to the discharge port 91. When the pump 99 starts to operate, liquid L is supplied to the applicator 90, and discharge of the liquid L begins from the discharge port 91. At this time, the liquid L is discharged from the entire width B of the discharge port 91. Note that the substrate W in each of Figures 10A, 10B, and 10C is shown including a cross section (cross section as viewed from the X1-X1 arrow) passing through one end Wa of the substrate W shown in Figure 9.

As shown in FIG. 10B, a portion of the discharged liquid L adheres to one end Wa of the substrate W. The liquid L is discharged from the entire width B of the discharge port 91, but because the substrate W is circular, only a central portion of the discharged liquid La adheres to the one end Wa, and a bead LB of liquid L is formed between the tip surface 92 of the applicator 90 where the discharge port 91 opens and the one end Wa of the substrate W. In contrast, the remaining liquid Lb on both sides of the central portion of liquid La does not adhere to the substrate W. The operation of applying the liquid L to the one end Wa of the substrate W in this manner is called the liquid application operation, and the process of applying the liquid L to the one end Wa is called the liquid application process.

When the liquid L adheres to one end Wa, the pump 99 is stopped and the substrate W and the applicator 90 are moved relative to each other. Before that, the valve 96 of the flow path 98 connecting the applicator 90 and the tank 97 is opened (see FIG. 10C). The liquid L in the tank 97 is depressurized in advance. When the valve 96 is opened, the liquid L in the applicator 90 is also depressurized. When the pressure of the liquid L in the applicator 90 stabilizes at a predetermined value (slightly negative pressure relative to atmospheric pressure), the substrate W and the applicator 90 start to move relative to each other. As a result, the liquid L in the applicator 90 is drawn toward the substrate W by the liquid L in contact with the substrate W, and the liquid L is applied to the substrate W (see the upper diagram in FIG. 11). This application is called capillary application. The upper diagram in FIG. 11 is a diagram of the substrate W and the applicator 90 viewed along the coating progress direction, and the lower diagram is a plan view. The substrate W shown in the upper diagram of FIG. 11 is shown including a cross section (cross section taken along the X2-X2 arrows) passing through the middle part of the substrate W shown in FIG. 9.

10B, during the liquid application step, the liquid L tends to collect due to surface tension at the edges We on both sides of one end Wa of the substrate W. For this reason, a liquid pool Ls is formed near the edge We at the tip of the applicator 90. To be more specific, since the liquid L tends to collect near the edge We, the liquid L also adheres to the side surface 93 of the applicator 90, which is inclined beyond the tip surface 92 where the discharge port 91 opens (see the side view on the left in FIG. 10B).
Then, as described above, after the liquid landing process, as shown in FIG. 10C, the valve 96 is opened, and the relative movement is put on hold until the pressure of the liquid L in the applicator 90 stabilizes at a predetermined negative pressure value. However, since the valve 96 is in the open state, it is possible for the liquid L to flow between the tank 97 and the applicator 90. Therefore, until the relative movement begins, the surface tension of the liquid L acts strongly only on the edge We of the substrate W, drawing out the liquid L and causing the liquid puddle Ls to become larger (grow).

When the applicator 90 and the substrate W start to move relative to each other with the liquid puddle Ls large, the liquid in the liquid puddle Ls is applied to the substrate W together with the liquid L discharged from the discharge port 91. Then, as shown in the lower diagram of Fig. 11, a streak J is formed in the coating film of the liquid L formed on the substrate W at a position corresponding to the liquid puddle Ls. The film thickness is not constant in the portion where the streak J is formed, and the substrate W becomes a defective product.
Therefore, the invention of the present disclosure aims to make it possible to apply liquid while suppressing the effect of liquid gathering at the edge of a substrate when the substrate is applied with the liquid.

The coating device of the present disclosure includes an applicator having a long outlet at its tip in one direction, a movement mechanism for moving the applicator relative to the substrate in a direction intersecting the one direction, a tank for storing liquid, a flow path connecting the applicator and the tank, a valve provided in the flow path, and an adjustment path having a pressure adjustment means for reducing the pressure of the liquid in the tank, and a control device for controlling the movement mechanism, the valve, and the pressure adjustment means. The control device is capable of performing a liquid deposition control for discharging liquid from the outlet and depositing the liquid on the edge of the substrate, and a coating control for performing the relative movement to apply the liquid to the substrate while reducing the pressure of the liquid in the applicator by reducing the pressure of the liquid in the tank and opening the valve, and the coating control controls the valve to start opening after the relative movement begins.

According to the coating device, even if a liquid pool occurs near the edge of the substrate at the tip of the applicator after the liquid is discharged from the discharge port of the applicator and applied to the end of the substrate, the relative movement between the substrate and the applicator begins before the valve starts to open. Therefore, liquid is not supplied from the tank to the applicator when the relative movement is not occurring. The position of the edge of the substrate facing the discharge port gradually moves in a direction parallel to the longitudinal direction of the applicator as the relative movement occurs, so that when the relative movement begins, the liquid pool caused by the edge is pulled in the longitudinal direction and spreads, and the liquid pool does not become larger. As a result, the effect of the liquid pool occurring at the tip of the applicator when the liquid is applied is suppressed, and the liquid can be applied.

Also, preferably, when liquid adheres to the end of the substrate, the control device performs the relative movement at a first speed, and then changes the speed to a second speed higher than the first speed, as the coating control, and initiates an opening operation of the valve between when the relative movement starts at the first speed and when it is changed to the second speed.
In this case, the diffusion of the liquid pool can be started while the relative movement is performed at the first low speed. Therefore, the diffusion of the liquid pool can be promoted while the liquid is being applied to the edge of the substrate. Then, as the diffusion progresses, the application is continued at the second high speed, and the effect of the liquid pool is suppressed and the efficiency of the application work is improved.

Also preferably, the controller changes to the second speed when it detects that the pressure of the liquid in the applicator has stabilized.
According to the above configuration, when the valve is opened and the pressure of the liquid in the applicator is made negative, and the pressure stabilizes, it is possible to quickly change the speed of the relative movement to a second speed which is higher, thereby increasing the efficiency of the coating operation, and furthermore, since the pressure of the liquid in the applicator is stable, coating with high film thickness accuracy is possible.

In a preferred embodiment, the control device executes, as the liquid landing control, control for depositing liquid on the edge portion of the substrate in a state in which the relative movement is not being performed.
According to the above-mentioned configuration, the liquid is applied accurately.

In a preferred embodiment, the control device starts the relative movement when a liquid landing signal is obtained, which is generated by confirming that the liquid has adhered to the end portion of the base material.
With this configuration, it becomes possible to quickly and reliably apply the liquid to the substrate after the liquid has landed on the substrate.

In a preferred embodiment, the application device further includes an independent supply path that is provided separately from the adjustment path and is capable of supplying liquid to the applicator, and the control device controls the liquid delivery by supplying liquid through the supply path with the valve closed.
In this case, as a liquid landing control, by supplying liquid through the supply path with the valve closed, the liquid can be discharged from the discharge port of the applicator to adhere to the edge of the substrate. The liquid landing control is performed by the supply path, which is separate from the adjustment path, and after the liquid landing, it becomes easy to control the start of the opening operation of the valve after the start of the relative movement.

The coating method of the present disclosure comprises an applicator having a long outlet at its tip in one direction, a tank for storing liquid, a flow path connecting the applicator and the tank, a valve provided in the flow path, and an adjustment path having a pressure regulating means for reducing the pressure of the liquid in the tank, and is performed by discharging liquid from the outlet onto the substrate while moving the applicator and substrate relative to each other in a direction intersecting the one direction, and includes a liquid deposition process in which liquid is discharged from the outlet to adhere to an end of the substrate, and a coating process in which the liquid in the tank is reduced in pressure and the valve is opened to reduce the pressure of the liquid in the applicator while performing the relative movement to apply the liquid to the substrate, and during the coating process, the opening operation of the valve is started after the start of the relative movement.
The coating method can be performed by the coating device, and therefore, the liquid can be applied while suppressing the influence of liquid pooling that occurs at the tip of the applicator when the liquid is applied.

When applying liquid to the edge of a substrate, the liquid tends to collect at the edge of the substrate, but this effect can be reduced and the liquid can be applied.

FIG. 2 is a schematic diagram illustrating an example of a coating device. FIG. 2 is a perspective view of an applicator and a substrate. FIG. FIG. FIG. FIG. FIG. FIG. 2 is an illustration of a substrate and an applicator. FIG. 2 is an illustration of a substrate and an applicator. FIG. 4 is a flow diagram illustrating a coating method. FIG. 4 is a flow diagram illustrating a coating method. FIG. FIG. 1 is an explanatory diagram of a conventional coating method. FIG. 1 is an explanatory diagram of a conventional coating method. FIG. 1 is an explanatory diagram of a conventional coating method. 1A to 1C are diagrams illustrating problems with a conventional coating method.

[Configuration of Coating Apparatus]
FIG. 1 is a schematic diagram showing an example of a coating device. The coating device 10 shown in FIG. 1 is a device for coating a substrate W with a liquid L. As will be described later, the coating device 10 includes an applicator 11 having a discharge port 23 that is long in one direction, and discharges the liquid L from the discharge port 23 while moving the applicator 11 and the substrate W relative to each other. As a result, the liquid L is applied to a surface to be coated, which is one surface of the substrate W. To perform such coating, the coating device 10 includes the applicator 11, a moving mechanism 12, an adjustment path 13, and a control device 14. The coating device 10 of the present disclosure further includes a supply path 15, a stage 16, and a support unit 17.

Figure 2 is a perspective view of the applicator 11 and the substrate W. The applicator 11 is also called a slit die, and is a member that is long in one direction. This one direction, i.e., the longitudinal direction of the applicator 11, is defined as the "first direction." The "first direction" is indicated by arrow X in Figures 1 and 2. The applicator 11 is mounted on a support portion 17 (see Figure 1) provided in the coating device 10.

A liquid storage space 21 in which liquid is stored and a slit 22 are formed in the applicator 11. The liquid storage space 21 and the slit 22 are formed in a long straight line along the first direction. One side of the slit 22 (upper side in FIG. 1) opens into the liquid storage space 21 and is connected to the liquid storage space 21. The other side of the slit 22 (lower side in FIG. 1) opens at the tip surface 24 of the applicator 11. The opening of the slit 22 is the discharge port 23 that discharges the liquid L. The dimension of the discharge port 23 in the first direction is larger than the diameter (width dimension in the first direction) of the substrate W (see FIG. 2). The liquid L supplied to the applicator 11 and temporarily stored in the liquid storage space 21 is discharged from the discharge port 23 to the external space through the slit 22. The tip surface 24 of the applicator 11 faces the substrate W, and the liquid L discharged from the discharge port 23 is applied to the substrate W.

The movement mechanism 12 moves the applicator 11 and the substrate W relative to each other. In the present disclosure, the stage 16 holding the substrate W is moved relative to the applicator 11, which is in a stationary state. The direction of movement of the applicator 11 relative to the moving substrate W is the "coating progress direction", which is perpendicular to the first direction. The coating progress direction is defined as the "second direction", and the "second direction" is indicated by arrow Y in Figures 1 and 2, etc.

The direction perpendicular to both the first and second directions, from the liquid storage space 21 toward the opening of the slit 22 (discharge port 23), is defined as the "third direction." The "third direction" is indicated by arrow Z in Figures 1 and 2, etc. In the invention disclosed herein, the first and second directions are directions along a horizontal plane, and the third direction is a direction from top to bottom along a vertical line.

As shown in FIG. 2, the substrate W of the present disclosure is a circular plate like a typical semiconductor wafer. The substrate W may be other than circular, and the contour shape of the substrate W is such that in the first half of the second direction region of the substrate W, the dimension in the first direction (substrate width) gradually increases as it approaches the second direction. The contour shape of the substrate W is such that in the remaining second half of the second direction region, that is, from the middle of the second direction, the dimension in the first direction (substrate width) decreases as it approaches the second direction.

1, the stage 16 holds the substrate W, for example, by suction of air. When applying the liquid L to the substrate W, the applicator 11 is located above the substrate W. The moving mechanism 12 of the present disclosure has a configuration for moving the stage 16 with respect to the applicator 11, which is in a stationary state. Specifically, the stage 16 is provided so as to be movable back and forth along the second direction and the opposite direction, and the moving mechanism 12 has an actuator 26 for moving the stage 16. The actuator 26 is, for example, a linear actuator. The substrate W moves with the surface to be coated of the substrate W in a horizontal state. Note that, contrary to the configuration of the present disclosure, the stage 16 may be in a stationary state and the support part 17 on which the applicator 11 is mounted may move. In other words, the moving mechanism 12 may be configured to relatively move the substrate W and the applicator 11 in a direction intersecting the longitudinal direction of the applicator 11. The start of the relative movement by the moving mechanism 12, the stop of the movement, and the change in the speed of the movement are controlled by the control device 14.

As described above, while the substrate W moves relative to the applicator 11, the liquid L is discharged from the outlet 23 of the applicator 11, and capillary coating is performed, as will be explained later. In order to adjust the distance (gap) between the outlet 23 of the applicator 11 and the substrate W, the applicator 11 is mounted on the support part 17 and is movable in a direction perpendicular to the surface to be coated (the third direction and the opposite direction).

In FIG. 1, the adjustment path 13 includes a tank 31 for storing liquid L, a pipe 32 that constitutes a flow path connecting the applicator 11 and the tank 31, a valve 33 provided in the pipe 32, and a pressure adjusting means 34 that reduces the pressure of the liquid L in the tank 31 and adjusts the pressure of the liquid L. The valve 33 is a valve that opens and closes. When the valve 33 is in an open state, the liquid L can flow between the applicator 11 and the tank 31 through the pipe 32. When the valve 33 is in a closed state, the liquid L cannot flow between the applicator 11 and the tank 31 through the pipe 32. The valve 33 has a drive unit that operates the valve body for opening and closing operations. The drive unit operates based on the control performed by the control device 14. The control device 14 generates, for example, a signal (open operation signal) that opens the valve 33.

The pressure adjusting means 34 has a suction pump (vacuum pump) 35 and a regulator 36. The suction pump 35 can reduce the pressure inside the tank 31 to reduce the pressure of the liquid L stored in the tank 31, and the regulator 36 can adjust the pressure of the liquid L in the tank 31. The pressure adjusting means 34 makes the liquid L in the tank 31 negative relative to atmospheric pressure. In this state, when the valve 33 is opened, the liquid L in the applicator 11 also becomes negative relative to atmospheric pressure.
A pressure sensor 39 is provided in the applicator 11, and the pressure sensor 39 detects the pressure of the liquid L in the applicator 11. The control device 14 acquires the measurement value of the pressure sensor 39 and controls the regulator 36 based on the measurement value. The pressure of the liquid L stored in the tank 31 is adjusted by the pressure adjustment means 34 so that the pressure of the liquid L in the applicator 11 is maintained at a predetermined value (negative pressure) by the pressure sensor 39. The pressure adjustment means 34 can adjust the pressure of the liquid L in the applicator 11 to a negative pressure with respect to atmospheric pressure, thereby enabling capillary application by the applicator 11. Capillary application will be described later. In addition to the operation of the pressure adjustment means 34, the opening and closing operation of the valve 33 is controlled by the control device 14.

The supply path 15 has a supply pump 38 connected to the applicator 11 through a second flow path (piping 37). The supply pump 38 is a fixed-volume pump that can supply a fixed amount of liquid L to the applicator 11 per unit time. When the supply pump 38 starts to operate and supplies liquid L to the applicator 11, the liquid L begins to be discharged from the discharge port 23 of the applicator 11, and the liquid L can be attached to one end Wa of the substrate W. In addition, since the liquid L in the applicator 11 is consumed by applying the liquid L to the substrate W, the liquid L can be replenished to the applicator 11 by the supply pump 38. In this way, the supply path 15 is connected to the applicator 11 and can supply the liquid L to the applicator 11. Note that when the liquid L is applied to the substrate W, the liquid L may be replenished to the applicator 11 by the adjustment path 13. In other words, the liquid L in the tank 31 may be replenished to the applicator 11.

The control device 14 is called a control unit and includes a computer. A program stored in the computer is executed by the computer's processing unit (CPU), thereby controlling the operation and timing of each part of the coating device 10 and coating the liquid onto the substrate W. The control device 14 has a function of controlling the movement of the substrate W (stage 16) relative to the coater 11 by controlling the operation of the movement mechanism 12, i.e., the actuator 26. The control device 14 also has a function of controlling the operation of the supply pump 38, the valve 33, and the pressure adjustment means 34.

As will be described later, in order for the coating device 10 to coat the substrate W with the liquid L, the liquid L discharged from the coater 11 is adhered to one end Wa of the substrate W. The operation of adhering the liquid L to the one end Wa in this manner is referred to as a liquid landing operation, and the process of adhering the liquid L to the one end Wa is referred to as a liquid landing process.
The coating device 10 of the present disclosure further includes a liquid-landing detection means 18 that detects that the liquid L has been completely attached to the one end Wa. The liquid-landing detection means 18 includes at least one of, for example, a camera 40, the pressure sensor 39, and a measuring device 41 that determines the amount of liquid L supplied from the supply pump 38. When it is detected that the liquid L has been completely attached to the one end Wa, the liquid-landing detection means 18 generates a liquid-landing signal. The liquid-landing signal is a signal that is generated when the attachment of the liquid L to the one end Wa is confirmed. The control device 14 acquires the liquid-landing signal and proceeds to the next operation.

The camera 40 captures an image between one end Wa of the substrate W and the tip surface 24 of the applicator 11 approaching the one end Wa, and detects that the liquid L has adhered to the one end Wa by image analysis processing. The image analysis processing may be performed by the control device 14.
The pressure sensor 39 detects the pressure of the liquid L in the applicator 11 from moment to moment. When the liquid L adheres to one end Wa, the pressure of the liquid L in the applicator 11 changes, albeit slightly. This change is detected by the pressure sensor 39. In other words, in the liquid application process, the pressure sensor 39 detects the pressure of the liquid L in the applicator 11, and when the pressure changes beyond a predetermined threshold, it can be detected that the application of the liquid L to one end Wa has been completed.
In the liquid application step (liquid application operation), the supply pump 38 supplies the liquid L to the applicator 11. The path from the supply pump 38 through the applicator 11 to the one end Wa of the substrate W is known, and the length of the path does not change, so that the total amount of liquid L supplied by the supply pump 38 required for the liquid L to adhere to the one end Wa can be checked in advance. The amount of liquid L supplied by the supply pump 38 is calculated (integrated) by the measuring device 41, and when the amount of liquid L supplied by the supply pump 38 reaches a preset value, it can be detected (estimated) that the liquid L has been applied to the one end Wa.

[Coating method]
The coating method performed by the coating device 10 having the above configuration will be described with reference to Figures 3A to 6. Figures 7 and 8 are flow diagrams explaining the coating method, and "steps S1 to S5" described below are the steps shown in Figure 7, and "steps S11 to S18" are the steps shown in Figure 8.
The stage 16 carrying the substrate W is moved by the moving mechanism 12 (step S1), and when the discharge port 23 of the applicator 11 is positioned above one end Wa of the substrate W, the stage 16 is stopped (step S2). With the substrate W stationary and the one end Wa approaching the discharge port 23, the supply pump 38 starts to operate (step S3). The liquid L is supplied to the applicator 11, and discharge of the liquid L starts from the discharge port 23 (see FIG. 3A). At this time, the liquid L is discharged from the full width B of the discharge port 23. The substrate W in each of FIGS. 3A, 3B, and 3C is shown including a cross section (cross section of the X1-X1 arrow) passing through one end Wa of the substrate W shown in FIG. 2.

As shown in FIG. 3B, a portion of the ejected liquid L adheres to one end Wa of the substrate W. The liquid L is ejected from the entire width B of the ejection port 23, but because the substrate W is circular, only a central portion of the ejected liquid La adheres to the one end Wa, and a bead LB of liquid L is formed between the tip surface 24 of the applicator 11 where the ejection port 23 opens and the one end Wa. In contrast, the remaining liquid Lb on either side of the central portion of the liquid La does not adhere to the substrate W.

When the liquid L adheres to the one end Wa (see FIG. 3B), the liquid arrival detection means 18 (see FIG. 1) detects the completion of the adhesion of the liquid L to the one end Wa (step S4). The control device 14 acquires the liquid arrival signal generated by the liquid arrival detection means 18 and outputs a command signal to stop the supply pump 38 and terminate the supply of the liquid L (see FIG. 3C, step S5).

The supply of the liquid L by the supply pump 38 is started and ended based on a command signal from the control device 14. That is, as the liquid deposition control, the control device 14 performs control for discharging the liquid L from the discharge port 23 of the applicator 11 and attaching the liquid L to one end Wa of the substrate W. As shown in Figures 3A and 3B, as the liquid deposition control, the control device 14 performs the supply of the liquid L through the supply path 15 having the supply pump 38 with the valve 33 closed.
Furthermore, in the present disclosure, the control device 14 executes control for performing the liquid L adhesion to the one end Wa in a state where there is no relative movement between the substrate W and the applicator 11, as the liquid arrival control. This allows the liquid L to be accurately applied to the one end Wa. This is the liquid arrival process.

As shown in FIG. 3B, during the liquid application process, the liquid L is likely to collect due to surface tension at the edges We on both sides of one end Wa of the substrate W. For this reason, a liquid pool Ls is formed near the edge We at the tip of the applicator 11. To be more specific, since the liquid L is likely to collect near the edge We, the liquid L also adheres to the side surface 25 of the applicator 11, which is inclined beyond the tip surface 24 where the discharge port 23 opens (see the side view on the left side in FIG. 3B). In this way, a liquid pool Ls is formed at the tip of the applicator 11 at a position corresponding to the edge We. The liquid pool Ls is generated due to the edge We of the substrate W.
3C, when the liquid application operation is completed, the supply pump 38 is stopped and the valve 33 is closed. Therefore, the liquid L is not supplied to the applicator 11, and the liquid pool Ls, even if it has been generated, is maintained as it is without increasing in size.

As shown in FIG. 3C, during the liquid application process (FIG. 7) and when the subsequent application process is started, the valve 33 is in a closed state (step S11 in FIG. 8). In addition, the pressure of the liquid L in the tank 31 is reduced to a predetermined value that is a negative pressure relative to atmospheric pressure by the pressure adjusting means 34 (step S12).

As described above, when the liquid landing is completed, the liquid landing detection means 18 outputs a liquid landing signal. When the control device 14 obtains the liquid landing signal (step S13), it outputs an operation signal to the movement mechanism 12 to start the relative movement between the substrate W and the applicator 11 (step S14). As shown in FIG. 4A, the valve 33 remains closed, and the movement mechanism 12 starts the relative movement between the substrate W and the applicator 11. The start of the relative movement is the start of the coating process. The speed of this relative movement is a first speed V1, which is slower than a second speed V2 described later (V1<V2). The relative movement at the first speed V1 is a slight movement, and the first speed V1 is extremely slow.
In the present disclosure, the relative movement starts after the supply pump 38 has completely stopped, but if the liquid arrival signal has been acquired, the relative movement may start before the supply pump 38 has stopped.

Here, FIG. 5 and FIG. 6 are explanatory views of the substrate W and the applicator 11. As shown in FIG.
(A) in FIG. 5 is a plan view showing a state where the discharge port 23 of the applicator 11 and the center C of the substrate W are separated by a distance y1 in the second direction, and (B) in FIG. 5 is a view of the substrate W and the applicator 11 shown in (A) in FIG. 5 viewed along the second direction. (A) and (B) in FIG. 5 show the state immediately after the liquid landing operation is completed. (A) in FIG. 6 is a plan view showing a state where the discharge port 23 of the applicator 11 and the center C of the substrate W are separated by a distance y2 (y1>y2) in the second direction, and (B) in FIG. 6 is a view of the substrate W and the applicator 11 shown in (A) in FIG. 6 viewed along the second direction. (A) and (B) in FIG. 6 show a state where the relative movement is slightly performed at the first speed V1 from the state shown in (A) and (B) in FIG. 5.

As is clear from a comparison of the states shown in (A) and (B) in FIG. 5 with the states shown in (A) and (B) in FIG. 6, when the substrate W and the applicator 11 move relative to each other, the position of the edge We of the substrate W facing the discharge port 23 gradually moves in the second direction. The width of the range in which the liquid L adheres to the substrate W is from one edge We facing the discharge port 23 to the other edge We. As shown in FIG. 5, immediately after the liquid landing operation is completed, the edge We is in a position where the width is narrow "K1", but as shown in FIG. 6, as the relative movement progresses, the edge We is in a position where the width is wide "K2". Since the substrate W is circular, as described above, when the relative movement is performed, the position of the edge We of the substrate W facing the discharge port 23 gradually moves in the second direction.
3C to 4A, since the liquid pool Ls is generated due to the edge We as described above, the liquid pool Ls is pulled and diffused by the moving edge We in the longitudinal direction (first direction) of the applicator 11 as the relative movement occurs. Then, it is possible to make the liquid pool Ls disappear in due course.

Returning to the description of the coating step of the coating method (see FIG. 8 ).
As described above, when the relative movement starts at the first speed V1 after the liquid has landed (step S14), the valve 33 opens (step S15), and the valve 33 remains open during the relative movement (see FIG. 4B). Before the valve 33 starts to open, that is, when the valve 33 is closed (step S11), the liquid L in the tank 31 is previously depressurized (step S12). Therefore, when the valve 33 starts to open after the relative movement starts, the liquid L in the applicator 11 is depressurized and stabilized at a predetermined pressure (negative pressure).
In this way, after the liquid is landed, the control device 14 performs control to start the opening operation of the valve 33 after the start of the relative movement between the substrate W and the applicator 11 at the first speed V1 (step S15). The opening operation of the valve 33 may start simultaneously with the start of the relative movement, but in the present disclosure, the opening operation is performed with a slight delay after the start of the relative movement.

When the relative movement is started at the first velocity V1, it is soon changed to a second velocity V2. The timing of this change and the control of the change will be described.
As described above, the pressure of the liquid L in the applicator 11 is detected by the pressure sensor 39 (step S16), and the control device 14 acquires the detection result. The control device 14 can detect that the pressure of the liquid L in the applicator 11 has stabilized (step S17) on the condition that the detection result of the pressure sensor 39 continues to fall between the upper threshold and the lower threshold. When the control device 14 detects that the pressure of the liquid L in the applicator 11 has stabilized, it changes the speed of the relative movement between the substrate W and the applicator 11 to a second speed V2 that is faster than the first speed V1 (step S18). In this way, by changing the speed to the second speed V2 and continuing the application while the pressure of the liquid L in the applicator 11 is stable, application with high film thickness accuracy is possible.

As described above, when the liquid adheres to one end Wa of the substrate W, the control device 14 performs the relative movement at a first speed V1 (step S14), and then changes the speed to a second speed V2 higher than the first speed V1 (step S18). In the present disclosure, the opening operation of the valve 33 is started during the period from when the relative movement starts at the first speed V1 to when it is changed to the second speed V2 (step S15).
While keeping the relative movement constant at the second speed V2, the relative movement is continued until the liquid L is applied up to the other end Wb of the substrate W (end of the application process).

Here, the area of the surface to be coated on the substrate W will be described. As shown in Figures 5 and 6, the surface to be coated on the substrate W has an effective area A1 where high film thickness accuracy is required, and an excluded area A2 around it (the periphery of the substrate W). The boundary between the effective area A1 and the excluded area A2 is indicated by a virtual line (two-dot chain line). The width dimension Q of the excluded area A2 is, for example, 2 millimeters or more and 10 millimeters or less.
In the present disclosure, the change from the first speed V1 to the second speed V2 is performed while a part of the discharge port 23 of the applicator 11 faces the exclusion area A2. That is, in the state shown in FIG. 6, the speed of the relative movement is changed to the second speed V2. More specifically, when the liquid landing operation is performed in the exclusion area A2, the relative movement between the substrate W and the applicator 11 is started, and at the beginning of the relative movement, the speed is set to a low speed (first speed V1), and while the relative movement is performed at the low speed, the opening operation of the valve 33 is started to stabilize the pressure of the liquid L in the applicator 11, and when it is detected that the pressure has stabilized, the speed is changed to the second speed V2, which is a high speed, while the discharge port 23 is passing directly above the exclusion area A2.

By controlling the moving speed in this manner by the control device 14, the liquid puddle Ls spreads due to the relative movement as described above, but the influence of the spreading liquid puddle Ls on the coating accuracy can be contained within the excluded area A2. To achieve this, the first speed V1 may be set to an extremely low speed.
This speed control allows the liquid pool Ls to be dispersed while the discharge port 23 of the applicator 11 passes directly above the exclusion area A2, and the liquid pool Ls is eliminated during that time. As a result, it becomes possible to make it difficult for the liquid pool Ls to affect the film thickness accuracy in the effective area A1.

[About capillary coating]
The liquid L is applied from one end Wa to the other end Wb of the substrate W by the relative movement between the substrate W and the applicator 11. The application of the liquid L by the coating device 10 of the present disclosure is capillary coating.
In order to perform capillary coating, before the start of coating, the pressure of the liquid L in the tank 31 is adjusted by the pressure adjusting means 34 to be lower than atmospheric pressure. As described above, the liquid application process is performed, and a bead LB of the liquid L is formed between one end Wa of the substrate W and the tip surface 24 of the applicator 11. Thereafter, when the relative movement between the substrate W and the applicator 11 is started, the valve 33 is opened, and the pressure of the liquid L in the applicator 11 becomes negative.

To continuously form a bead LB of liquid L with the relative movement, liquid L is drawn out from the applicator 11 so that the liquid L fills the gap between the substrate W and the tip surface 24 of the applicator 11, and the liquid L is continuously applied to the substrate W. This allows the liquid to be continuously applied to the substrate W. In this type of capillary application, liquid is discharged from the discharge port 23 only to the area where the substrate W is located directly below, and liquid is not discharged to the area where the substrate W is not located directly below.

As described above, in capillary coating, the liquid L ejected from the applicator 11 is attached to the substrate W, and in this state, the applicator 11 and the substrate W are moved relative to each other. Then, the liquid L attached to the substrate W generates a force that further draws the liquid L from the applicator 11, and the drawn liquid L is applied to the substrate W. In other words, when the substrate W and the applicator 11 move relative to each other while the liquid L is in contact with the substrate W, a force that draws the liquid L from the applicator 11 is generated, and thus the liquid L is applied to the substrate W. Such a force that draws the liquid L is generated by the shear force (viscous force) of the liquid generated by the movement of the substrate W.

[Coating device 10 and coating method performed by the coating device 10 according to the present disclosure]
The coating device 10 of the present disclosure includes a coater 11, a movement mechanism 12 that moves the coater 11 and the substrate W relative to each other, an adjustment path 13, and a control device 14. The adjustment path 13 has a tank 31 that stores the liquid L, a valve 33 provided in a pipe 32 that connects the coater 11 and the tank 31, and a pressure adjustment means 34 that reduces the pressure of the liquid L in the tank 31 and adjusts the pressure (reduced pressure adjustment). The control device 14 controls the movement mechanism 12, the valve 33, and the pressure adjustment means 34. The control device 14 is capable of executing liquid arrival control and coating control. The liquid arrival control is performed in a liquid arrival process, and the coating control is performed in a coating process.

The coating method performed by this coating device 10 is a coating method in which the substrate W and the applicator 11 are moved relative to each other while liquid L is ejected from the outlet 23 of the applicator 11 onto the substrate W, and includes a liquid deposition process and a coating process (see Figure 7).
In the liquid landing step, the liquid L is discharged from the discharge port 23 to adhere to one end Wa of the substrate W. When the liquid L has landed, the supply of the liquid L to the applicator 11 is stopped.
In the coating step, the liquid L in the tank 31 is depressurized and the valve 33 is opened to reduce the pressure of the liquid L in the applicator 11, while the relative movement is performed to coat the liquid L on the substrate W. Then, in the coating step, the opening operation of the valve 33 is started after the start of the relative movement (steps S14 and S15 in FIG. 8).

According to this coating device 10 and coating method, even if a liquid pool Ls occurs near the edge We (see FIG. 3B) of one end Wa of the substrate W at the tip of the applicator 11 after the liquid landing operation, the relative movement between the substrate W and the applicator 11 is started before the opening operation of the valve 33 begins. Therefore, liquid L is not supplied from the tank 31 to the applicator 11 when the relative movement is not performed. As described with reference to FIGS. 5 and 6, the position of the edge We of the substrate W facing the discharge port 23 gradually moves in a direction parallel to the longitudinal direction of the applicator 11 with the relative movement, so when the relative movement is started, the liquid pool Ls caused by the edge We is pulled in its longitudinal direction and spreads, and the liquid pool Ls does not become large. As a result, the effect of the liquid pool Ls generated at the tip of the applicator 11 when the liquid L is attached is suppressed, and the liquid can be applied.

In the coating device 10 of the present disclosure, the direction of the relative movement is unidirectional from the start to the end. Therefore, when the relative movement starts, the width of the substrate W at the position facing the discharge port 23 gradually increases, and the liquid in the liquid pool Ls is quickly consumed for coating the substrate W. Therefore, the liquid pool Ls is diffused (eliminated) immediately after the start of the relative movement.
In the present disclosure, the coating device 10 further includes an independent supply path 15 that is provided separately from the adjustment path 13 and is capable of supplying the liquid L to the applicator 11. In the liquid application step, the liquid L is applied to one end Wa of the substrate W by supplying the liquid L through the supply path 15 with the valve 33 closed.

The liquid landing process (liquid landing control) may be performed by supplying liquid L from the adjustment path 13, rather than by supplying liquid L from the supply path 15. In this case, the liquid landing process is controlled as follows: the pressure of liquid L in the tank 31 is set to atmospheric pressure, the valve 33 included in the adjustment path 13 is temporarily opened, and when the liquid is landed, the valve 33 is closed. Then, the application process is controlled as follows: after the start of the relative movement, the valve 33, which was closed, is opened. When the liquid landing process is performed by the adjustment path 13, the supply path 15 can be omitted.

In the present disclosure, the control device 14 performs the relative movement at a first speed V1, which is a low speed, and then changes the speed to a second speed V2, which is a high speed. Then, as shown in steps S14 to S18 in FIG. 8, the opening operation of the valve 33 is started during the period from when the relative movement starts at the first speed V1 to when it is changed to the second speed V2.
Therefore, the diffusion of the liquid pool Ls can be started while the relative movement is performed at the first speed V1, which is a low speed. Therefore, it is possible to advance the diffusion of the liquid pool Ls while the liquid L is being applied to the exclusion area A2 (see Figs. 5 and 6) which is the edge of the substrate W. In other words, it is possible to diffuse the liquid pool Ls in the exclusion area A2 around the substrate W, and to make the liquid pool Ls disappear at the stage of applying the liquid L to the effective area A1 inside the exclusion area A2. Then, as the diffusion advances (as the diffusion advances and the liquid pool Ls is eliminated), the application is continued at the second speed V2, which is a high speed, and the work efficiency of the application is improved while suppressing the influence of the liquid pool Ls.

〔others〕
In the present disclosure, after the liquid L is applied to one end Wa of the substrate W, the direction of the relative movement is unidirectional from the start to the end. As a modified example, the direction of the relative movement may be changed midway during the stage of eliminating the liquid pool Ls. That is, first, the relative positions of the applicator 11 and the substrate W are set to the state shown in FIG. 6, and the liquid application operation is performed in that state. Thereafter, the substrate W is moved in the opposite direction to the second direction (upward in FIG. 6), and when the relative positions of the applicator 11 and the substrate W are set to the state shown in FIG. 5, the direction of the relative movement is reversed. That is, the substrate W is moved in the second direction (downward in FIG. 6). Even in this case, it is possible to diffuse the liquid pool Ls by the relative movement between the substrate W and the applicator 11.
In the above embodiment, the case where the speed of the relative movement is changed from the first speed V1 to the second speed V2, which is faster, has been described, but the first speed V1 and the second speed V2 may be the same (V1=V2). In other words, the speed of the relative movement may be controlled so as not to change in appearance.

The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is not limited to the above-described embodiments, but includes all modifications within the scope of the claims that are equivalent to the configurations described therein.

10: Coating device 11: Applicator 12: Movement mechanism 13: Adjustment path 14: Control device 15: Supply path 23: Discharge port 31: Tank 32: Pipe (flow path)
33: Valve 34: Pressure adjusting means W: Substrate Wa: One end (end) L: Liquid

Claims (6)

an applicator having a discharge port at a tip end that is long in one direction;
a movement mechanism for moving the applicator and the substrate relative to each other in a direction intersecting the one direction;
a tank for storing liquid, a flow path connecting the applicator and the tank, a valve provided in the flow path, and an adjustment path having a pressure adjustment means for reducing and adjusting the pressure of the liquid in the tank;
a control device for controlling the moving mechanism, the valve, and the pressure adjusting means;
an independent supply path that is provided separately from the adjustment path and is capable of supplying liquid to the applicator;
Equipped with
The control device includes:
a liquid delivery control for supplying the liquid through the supply path while the valve is closed, and discharging the liquid from the discharge port to cause the liquid to adhere to the edge of the substrate;
a coating control for applying the liquid to the substrate by performing the relative movement while reducing the pressure of the liquid in the applicator by keeping the liquid in the tank in a reduced pressure state and the valve in an open state;
It is possible to execute
In the coating control, control is performed to start an opening operation of the valve after the start of the relative movement. When the liquid adheres to the end portion of the base material, the control device performs the relative movement at a first speed, and then changes the speed to a second speed higher than the first speed, as the coating control;
The coating apparatus according to claim 1 , wherein an opening operation of the valve is started during a period from when the relative movement is started at the first speed to when the relative movement is changed to the second speed. The applicator of claim 2, wherein the control device changes to the second speed when it detects that the pressure of the liquid in the applicator has stabilized. The coating device according to any one of claims 1 to 3, wherein the control device executes control for depositing liquid on the edge of the substrate when the relative movement is not being performed, as the liquid deposition control. The coating device according to any one of claims 1 to 4, wherein the control device starts the relative movement when a liquid landing signal is obtained, which is generated by confirming that the liquid has adhered to the end of the substrate. an applicator having a discharge port at a tip end that is long in one direction;
a tank for storing liquid, a flow path connecting the applicator and the tank, a valve provided in the flow path, and an adjustment path having a pressure adjusting means for reducing and adjusting the pressure of the liquid in the tank; and an independent supply path provided separately from the adjustment path and capable of supplying liquid to the applicator,
A coating method in which a liquid is discharged from the discharge port onto the substrate while the applicator and the substrate are moved relative to each other in a direction intersecting the one direction,
a liquid application step of supplying liquid through the supply path with the valve closed and discharging the liquid from the discharge port to adhere the liquid to the end of the substrate;
a coating step of applying the liquid to the base material by performing the relative movement while reducing the pressure of the liquid in the applicator by reducing the pressure of the liquid in the tank and opening the valve;
Including,
In the coating step, an opening operation of the valve is started after the relative movement is started.

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