JP6057370B2 - Coating method and coating apparatus - Google Patents

Description

  The present invention relates to a coating method and a coating apparatus for coating a coating liquid on a substrate such as glass and forming a coating film.

  A flat panel display such as a liquid crystal display or a plasma display uses a substrate coated with a resist solution (referred to as a coated substrate). In this coated substrate, a coating film is formed by uniformly coating a resist solution on the substrate by a coating apparatus as shown in Patent Document 1 below.

  An example of a coating apparatus is shown in FIG. The coating apparatus 90 includes a base 91 and a relative moving unit 92, and discharges the coating liquid from the base 91 in a strip shape while relatively moving the base 91 and the substrate W in one direction by the relative moving unit 92. A coating film having a substantially uniform film thickness is formed. However, it is difficult to apply uniformly to the application start portion and the application end portion, and the difference in film thickness is likely to occur at the application start portion as compared with other portions.

  Therefore, when the substrate W coated by the coating apparatus 90 is used for manufacturing a display or the like, the outer peripheral portion of the substrate W corresponding to the coating start portion and the coating end portion has a film thickness accuracy as shown by the width d in FIG. The non-required accuracy requirement exclusion region R1 is used. The portion inside the accuracy requirement exclusion region R1 is used as the accuracy requirement region R2 that requires the accuracy of the film thickness. In the subsequent process, the portion corresponding to the accuracy requirement exclusion region R2 is used. ing.

  In contrast to this operation method, in the conventional coating method, the time during which the base 91 is moving above the accuracy requirement exclusion region R1 after the coating device 90 starts coating above the accuracy requirement exclusion region R1 of the substrate W. In addition, the acceleration of the discharge speed of the coating liquid and the acceleration of the transport speed (relative movement speed) of the substrate W are completed at a stroke up to the final speed at the time of performing the coating, so that the accuracy-required region R2 has a constant discharge speed and transport speed. A uniform coating film can be formed.

JP 2002-66432 A

  However, the conventional coating method still has a problem that the film thickness may be nonuniform in the accuracy required region. Specifically, in recent years, in order to shorten the coating time, it has been demanded to increase the discharge speed of the coating liquid and the transport speed of the substrate W, and further, from the desire to increase the usage efficiency of the coated substrate, the accuracy requirement There has been a continuing demand for narrowing the width d of the exclusion region R1 and widening the accuracy requirement region R2. In this case, since the acceleration of the stage that transports the substrate W is limited, even if the discharge speed and the transport speed are accelerated to the final speed all at once, as shown in FIG. Before the transport speed reaches the final speeds Pa and Va, the boundary between the accuracy requirement exclusion region R1 and the accuracy requirement region R2 is reached at time tb (the moving distance of the substrate W represented by hatching in FIG. 8A). There is a possibility that the width of the accuracy requirement exclusion region R1 shown in FIG. That is, as shown in FIG. 8B, the acceleration cannot be completed within the time when the base 91 is located above the accuracy requirement exclusion region R1, and the acceleration may continue even above the accuracy requirement region R2. was there. As a result, since the uniformity of the film thickness deteriorates while the ejection speed and the conveyance speed are accelerated with a large acceleration, the film thickness accuracy in the accuracy required region R2 is insufficient.

  The present invention has been made in view of the above-described problems, and provides a coating method and a coating apparatus capable of coating a coating liquid with high accuracy and in a short time over the entire area where film thickness accuracy is required. It is an object.

In order to solve the above-described problems, the coating method of the present invention has a slit-like discharge port that is long in one direction, and a base that discharges the coating liquid from the discharge port, and the base and the substrate are short of the discharge port. The outer peripheral portion is coated by a coating device that includes a relative movement unit that relatively moves in the hand direction, and a control unit that controls a discharge speed of the coating liquid discharged from the discharge port and a relative movement speed by the relative movement unit. A base having an accuracy requirement exclusion region that does not require film thickness accuracy and having an accuracy requirement region that requires film thickness accuracy inside the accuracy requirement exclusion region is provided by the relative moving means. A coating method in which a coating film is formed by discharging a coating liquid from the discharge port while relatively moving, and the control unit is configured to remove the discharge port from the discharge port in a state where the discharge port is positioned above the accuracy requirement exclusion region. A starting step of starting the discharge of the cloth liquid and the relative movement, and the control means within a time during which the discharge port is positioned above the accuracy requirement exclusion region, and a discharge speed of the coating liquid from the discharge port; After the bead formation step, the bead formation step of accelerating the relative movement speed to a first discharge speed and a first movement speed capable of maintaining a bead by the coating liquid between the die and the substrate, An error in the film thickness of the coating film that is smaller than the ejection speed and the relative movement speed in the bead formation step and that occurs in the longitudinal direction of the ejection port due to the acceleration of the ejection speed. Is the acceleration within the range of the film thickness accuracy required for the coating film, and the discharge speed is set to the first discharge while keeping the application amount of the coating liquid per unit area on the substrate constant. Is accelerated to high speed second discharge speed than degrees, also the accelerating the relative moving speed to the high speed second moving speed than the first moving speed includes an acceleration step, and a said bead forming step Between the accelerating step, there is a stabilization step of performing application to the substrate while maintaining the discharge speed and the relative movement speed at the first discharge speed and the first movement speed for a predetermined time. Yes.

According to the coating method, by having the bead forming step and the accelerating step, the coating can be performed with high accuracy and in a short time over the entire region requiring accuracy. Specifically, the discharge port is positioned above the accuracy requirement exclusion area up to the first discharge speed and the first movement speed that are the minimum discharge speed and relative movement speed at which the bead can be maintained by the bead formation process. By accelerating in time, it is possible to prepare for applying the coating liquid so that the discharge port becomes a coating film having a predetermined film thickness before reaching the accuracy required region. In the acceleration step, the discharge speed and the relative movement speed can be accelerated while ensuring the film thickness accuracy, and then the high-speed application can be performed to complete the application in a short time. In addition, by having a stabilization process, even if an overshoot of the discharge amount of the coating liquid occurs at the end of the bead formation process, the overshoot can converge and the process can be shifted to the acceleration process. It is possible to keep the film thickness of the liquid constant.

  Further, in the acceleration step, the control means delays the timing of the ejection speed acceleration relative to the acceleration of the relative movement speed, so that the coating amount of the coating liquid per unit area on the substrate becomes constant. It is good to control.

  By doing so, it is possible to accelerate the discharge speed and the relative movement speed while keeping the film thickness of the coating solution in the acceleration step further constant.

  Moreover, the acceleration form of the discharge speed and the relative movement speed in the acceleration step may be S-shaped acceleration.

  In this way, by preventing a rapid change in acceleration, it is possible to prevent overshooting of the discharge amount of the coating liquid, thereby preventing the film thickness accuracy from deteriorating, and the discharge speed and transport speed without causing the bead to become unstable. Can be accelerated.

In order to solve the above-described problem, the coating apparatus of the present invention has a slit-like ejection port that is long in one direction, and a nozzle that discharges a coating liquid from the ejection port, and the nozzle and the substrate are connected to the ejection port. And a control means for controlling the discharge speed of the coating liquid discharged from the discharge port and the relative movement speed by the relative movement means. Relative movement of the die by the relative movement means with respect to a substrate having an accuracy requirement exclusion region that does not require film thickness accuracy, and an accuracy requirement region that requires film thickness accuracy inside the accuracy requirement exclusion region The coating device forms a coating film by discharging the coating liquid from the discharge port while the control unit is configured to apply the coating liquid from the discharge port in a state where the discharge port is located above the accuracy requirement exclusion region. Discharge And a start mode in which the relative movement is started, and the control means detects the discharge speed of the coating liquid from the discharge port and the relative movement speed within a time period during which the discharge port is located above the accuracy requirement exclusion region. Is accelerated to a first discharge speed and a first moving speed capable of maintaining a bead by the coating liquid between the die and the substrate, and after the bead formation mode, the control means An error in the film thickness of the coating film that is smaller than the acceleration of the discharge speed and the relative movement speed in the bead forming step and that occurs in the longitudinal direction of the discharge port due to the acceleration of the discharge speed. The discharge speed is equal to the first discharge speed while keeping the application amount of the coating liquid per unit area on the substrate constant at an acceleration within the range of the film thickness accuracy required for Also is accelerated to high speed second discharge speed, also the accelerating the relative moving speed to the high speed second moving speed than the first moving speed includes an acceleration mode, wherein the acceleration and the bead formation mode Between the modes, there is a stabilization mode in which coating is performed on the substrate while maintaining the discharge speed and the relative movement speed at the first discharge speed and the first movement speed for a predetermined time .

According to the coating apparatus, by having the bead formation mode and the acceleration mode, it is possible to perform the coating with high accuracy in the entire accuracy-required region. Specifically, the discharge port is positioned above the accuracy requirement exclusion area up to the first discharge speed and the first movement speed, which are the minimum discharge speed and relative movement speed at which the bead can be maintained in the bead formation mode. By accelerating in time, it is possible to prepare for applying the coating liquid so that the discharge port becomes a coating film having a predetermined film thickness before reaching the accuracy required region. In the acceleration mode, the discharge speed and the relative movement speed can be accelerated while ensuring the film thickness accuracy, and then the high-speed application can be performed to complete the application in a short time. In addition, by having the stabilization mode, even if an overshoot of the discharge amount of the coating liquid occurs at the end of the bead formation mode, the overshoot can converge and the mode can be shifted to the acceleration mode. It is possible to keep the film thickness of the liquid constant.

  According to the coating method and the coating apparatus of the present invention, it is possible to apply the coating solution with high accuracy and in a short time on the entire surface of the region where the film thickness accuracy is required.

It is the schematic of the coating device in one Embodiment of this invention, and is a perspective view. It is the schematic showing the coating film formation to the board | substrate by a coating device. It is the schematic showing the control method of the discharge speed of the coating liquid in the coating method of this embodiment, and the conveyance speed of a board | substrate. It is a graph showing the film thickness distribution of the coating film with respect to the longitudinal direction of a nozzle | cap | die. It is the schematic showing the control method of the discharge speed of the coating liquid and the conveyance speed of a board | substrate in the coating method of other embodiment. It is the schematic of the conventional coating device, and is a perspective view. It is an example of setting the accuracy requirement exclusion region and the accuracy requirement region on the substrate. It is the schematic showing the control method of the discharge speed of the coating liquid and the conveyance speed of a board | substrate in the conventional coating method.

  Embodiments according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view of a coating apparatus according to an embodiment of the present invention. The coating apparatus 1 includes a coating unit 2 that coats the substrate W with a coating solution, a relative movement unit 3 that relatively moves the base 11 and the substrate W included in the coating unit 2 (in this embodiment, a transport unit that transports the substrate W). And a coating film is formed on the substrate W by discharging the coating liquid from the discharge port 13 of the base 11 when the substrate W is being transported immediately below the base 11 by the relative movement means 3. .

  Further, the coating apparatus 1 further includes a control unit 4, which is a discharge speed when applying to the substrate W (discharge amount of the coating liquid per unit time), and a relative moving speed (conveying speed) of the base 11 and the substrate W Etc. are controlled.

  Here, the discharge speed in this description indicates the discharge amount of the coating liquid per unit time actually discharged from the discharge port 13. For example, when the viscosity of the coating liquid is high, there is a delay in the timing at which the discharge speed of the coating liquid actually discharged from the discharge port 13 is changed by the control with respect to the discharge speed control timing by the control means 4. In this case, it is assumed that the control means 4 performs the control early on the assumption of the delay.

  In the following description, the transport direction of the substrate W is the X-axis direction, the direction orthogonal to the X-axis direction on the horizontal plane (the longitudinal direction of the base) is the Y-axis direction, and the direction orthogonal to both the X-axis and Y-axis directions. The description will proceed with Z as the Z-axis direction.

  The coating means 2 includes a base 11. The base 11 is a metal block having a substantially rectangular parallelepiped shape, and has a slit having a longitudinal direction (Y-axis direction) in a direction perpendicular to the transporting direction of the substrate W by the relative movement means 3. . The base 11 has a lip 12 at the bottom.

  The lip 12 has a shape protruding in a bowl shape that tapers downward from the base 11, and a discharge port 13 that is an opening portion of the slit and whose longitudinal direction is the Y-axis direction is formed at the lower end. Yes. And the coating liquid supplied to the nozzle | cap | die 11 from the coating liquid supply apparatus which is not shown in figure is discharged downward from this discharge port 13 through the said slit.

  Further, the discharge port 13 is set at a position in the Z-axis direction so as to be separated from the substrate W by a predetermined distance when coating is performed. Here, the application means 2 is also provided with a drive mechanism (not shown) in the Z-axis direction so that the position of the discharge port 13 in the Z-axis direction can be adjusted.

  The relative moving means 3 is a linear motion mechanism constituted by a linear stage or the like, and moves the mounting portion 21 assembled to the relative moving means 3 in the X-axis direction. Then, the control unit 4 controls driving of the relative moving unit 3 in a state where the mounting unit 21 has mounted the substrate 11, whereby the base 11 and the substrate W are relatively moved in the X-axis direction. Then, the coating liquid can be applied to the substrate W by discharging the coating liquid from the discharge port 13 of the base 11 while relatively moving the substrate W below the base 11.

  The placement unit 21 has a mechanism for fixing the substrate W, and the coating operation on the substrate W is performed with the substrate W placed on the placement unit 21 and fixed. In the present embodiment, the mounting portion 21 has a suction mechanism, and by operating a vacuum pump (not shown) or the like, a suction force is generated on the surface in contact with the substrate W, and the substrate W is sucked and fixed. .

  In this embodiment, the relative moving means 3 is a form for moving the substrate W, but is a form for relatively moving the base 11 and the substrate W by moving the coating means 2 including the base 11. May be. Furthermore, the relative movement means 3 may be in a form in which the substrate W is lifted by air or the like and transported instead of transporting the substrate W fixed in the placement unit 21.

  The control unit 4 includes a computer, a sequencer, and the like, and controls the discharge speed of the coating liquid from the discharge port 13, the transport speed of the substrate W (moving speed of the placement unit 21), and the like. The control means 4 has a storage device for storing various information including a hard disk, a memory such as a RAM or a ROM, and the control data for the ejection speed and the transport speed at the time of application are stored in this storage device. Is done.

  Next, the form of application of the coating liquid from the base 11 to the substrate W is shown in FIG.

  As described above, when the substrate W is positioned below the base 11, the coating liquid supplied to the base 11 from a coating liquid supply device (not shown) is discharged from the discharge port 13 to the substrate W through the slit and applied. A film 14 is formed.

  Here, when the application to the substrate W is started, first, the base 11 and the substrate W are connected by the coating liquid discharged from the discharge port 13 of the base 11. The state in which the base 11 and the substrate W are thus connected by the coating liquid is referred to as “the state in which the beads 15 are formed” in the present invention. Then, by maintaining the discharge speed of the coating liquid and the transport speed of the substrate W at a predetermined speed or more, the substrate W can relatively move below the base 11 while maintaining the state where the beads 15 are formed. .

  In this way, the coating film 14 can be formed on the entire surface of the substrate W without interruption by applying the substrate W while moving relative to the lower side of the base 11 while maintaining the state where the beads 15 are formed. It is. In addition, application is performed with a uniform film thickness by applying the application liquid while controlling the discharge speed of the application liquid and the conveyance speed of the substrate W so that the amount of the application liquid applied per unit area of the substrate W is constant. A film 14 is formed.

  Next, a coating liquid coating method according to an embodiment of the present invention will be described.

  FIG. 3 is a schematic view showing a method for controlling the discharge speed of the coating liquid and the transport speed of the substrate in the coating method of the present embodiment, and FIG. 3A is a graph showing the change over time of the discharge speed and the transport speed. FIG. 3B is a schematic diagram showing the relative positions of the discharge port 13 of the base 11 and the substrate W at times t1, t2 and t4 in FIG.

  The substrate W to be coated in the present invention is provided with an accuracy requirement exclusion region R1 that does not require film thickness accuracy as shown in FIG. 7 at the outer periphery, and a portion inside the accuracy requirement exclusion region R1 is, This is the accuracy required region R2 that requires the accuracy of the film thickness. The width of the accuracy requirement exclusion region R1 is about 10 mm.

  Thus, in performing application | coating to the board | substrate W which has the precision requirement exclusion area | region R1 and the precision requirement exclusion area | region R2, first, the control means 4 from the state which the discharge port 13 of the nozzle | cap | die 11 is located above the precision requirement exclusion area | region R1 of the board | substrate W. Starts the discharge of the coating liquid from the discharge port 13 and the conveyance of the substrate W. This process is called a start process. Moreover, it is called start mode that the coating device 1 performs this start process.

  With regard to this starting step, in the present embodiment, the discharge of the coating liquid and the conveyance of the substrate W are started at the time t0 shown in FIG. 3A, but it is not always necessary. For example, the conveyance of the substrate W may be started after a predetermined amount of the coating liquid is discharged.

  In the present embodiment, in order to prevent the coating liquid from dripping down from the substrate W, the coating is started from the state where the discharge port 13 is located above a position several mm inside from the substrate end. The position of the discharge port 13 is above the accuracy requirement exclusion region R1.

  After this starting step, coating is performed while the discharge speed of the coating liquid from the discharge port 13 and the transport speed of the substrate W are accelerated. In the coating method of the present invention, at least the step of changing the discharge speed and the transport speed is performed. I have two.

  First, the control means 4 sets the discharge speed of the coating liquid from the discharge port 13 and the transport speed of the substrate W to the first discharge speed P1 and the first movement speed V1 shown in FIG. Accelerate the process. This process is called a bead formation process. Moreover, it is called bead formation mode that the coating device 1 performs this bead formation process.

  Here, the first discharge speed P1 and the first moving speed V1 maintain the state in which the beads 15 are formed between the base 11 and the substrate W, and the coating film 14 having a predetermined thickness is formed on the substrate W. It is the minimum necessary coating liquid discharge speed and the substrate W transport speed that can be applied, and is lower than the maximum discharge speed and the maximum transport speed that are reached to perform coating on the entire surface of the substrate W. is there.

  Here, as described above, in order to maintain the state in which the bead 15 is formed between the base 11 and the substrate W, a discharge speed and a transport speed that are equal to or higher than a predetermined speed are required. If these are less than the predetermined speed, the bead 15 cannot be maintained and the coating solution is torn off from the base 11, and as a result, the coating film 14 cannot be formed on the entire surface of the substrate W without interruption.

  Further, since the film thickness of the coating film 14 formed on the substrate W is determined by the amount of the coating liquid ejected per unit area of the substrate W, even when the ejection speed and the transport speed are changed, The control means 4 controls the discharge speed and the transport speed so that the ratio (discharge speed / transport speed) becomes a predetermined value, whereby the coating film 14 having a predetermined film thickness can be obtained.

  Therefore, in the bead formation process of the present embodiment, the control means 4 accelerates the discharge speed and the conveyance speed with a relatively large acceleration within the time when the discharge port 13 of the base 11 is located in the accuracy requirement exclusion region R1. Thus, a form that can be applied so as to maintain the bead 15 and form the coating film 14 having a predetermined film thickness is quickly formed.

  In the example of FIG. 3, the bead formation process is performed from time t0 to time t1, the discharge speed and the conveyance speed become the first discharge speed P1 and the first movement speed V1, respectively, the bead 15 is maintained, and a predetermined film thickness is obtained. The form which can be apply | coated so that the coating film 14 of this may be formed is formed.

  As shown in FIG. 3B, this bead formation process is performed within the time when the discharge port 13 is located in the accuracy requirement exclusion region R1, and then the discharge port 13 is at the accuracy requirement exclusion region at time t2. The boundary between R1 and the accuracy requirement region R2 is reached. That is, at time t2, the movement distance of the substrate W represented by hatching in FIG. 3A becomes the width d of the accuracy requirement exclusion region R1 shown in FIG. 3B.

  As a result, preparation for performing coating with a uniform film thickness on the entire surface of the accuracy requirement region R2 can be completed in the accuracy requirement exclusion region R1.

  Next, in the coating method according to the present embodiment, the control unit 4 performs a step of further accelerating the discharge speed of the coating liquid from the discharge port 13 and the transport speed of the substrate W. This process is called an acceleration process. Moreover, it is called acceleration mode that the coating device 1 performs this acceleration process.

  Here, if the application is performed while maintaining the discharge speed and the conveyance speed after the bead formation process is completed, it is possible to perform the application with a uniform film thickness on the entire surface of the accuracy required region R2. is there. However, since the operation is performed at a low speed, it takes time to complete the coating on the entire surface of the substrate W. Therefore, by providing this acceleration step and accelerating the discharge speed and the conveyance speed, it is possible to shorten the time until the application is completed.

  In this embodiment, from time t3 to time t4 in FIG. 3A, the discharge speed and the conveyance speed are accelerated from the first discharge speed P1 to the second discharge speed P2, and from the first movement speed V1 to the second movement speed V2. This operation corresponds to the acceleration process.

  Here, the second discharge speed P2 and the second movement speed V2 are the maximum speeds of the application operation in the present embodiment, respectively, and after the acceleration step, the second discharge speed P2 and the second movement speed V2 are maintained. Application to the entire surface of the substrate W is performed.

  In this acceleration step, the coating rate is accelerated while maintaining the film thickness uniform by accelerating the discharge speed and the transport speed while keeping the coating amount per unit area on the substrate W constant.

  Here, the control means 4 controls the discharge speed and the transport speed so as to keep the ratio of the discharge speed and the transport speed (discharge speed / transport speed) constant except for the influence of the volume change of the bead described later. It is possible to keep the coating amount per unit area almost constant.

  Further, in this acceleration step, the control means 4 performs the discharge speed in order to improve the film thickness uniformity and satisfy the film thickness accuracy (film thickness uniformity) of the coating film 14 required in the accuracy requirement region R2. It is necessary to reduce the acceleration. Accordingly, when the bead formation process is performed at a relatively large acceleration as described above, the film thickness accuracy may not be satisfied with the same acceleration as the acceleration in the bead formation process. Needs to be smaller than the acceleration of the discharge speed.

  Further, in order to keep the ratio between the discharge speed and the conveyance speed constant, it is necessary to reduce the acceleration of the conveyance speed together with the acceleration of the discharge speed.

  The reason why the acceleration of the discharge speed is reduced in the acceleration process will be described with reference to FIG.

  FIG. 4 is a graph showing the film thickness distribution of the coating film in the longitudinal direction of the die. The graph of FIG. 4A is a film when the acceleration is zero (the ejection speed is constant), the graph of FIG. 4B is the case where the acceleration is small, and the graph of FIG. 4C is the film when the acceleration is large. Thickness distribution.

  The base 11 is provided with a device such that the discharge amount from the discharge port 13 is uniform over the entire length of the discharge port 13. However, it is difficult to make it completely uniform, and the portion closer to the supply port of the coating liquid to the base 11 tends to have a larger discharge amount. This tendency becomes more prominent as the discharge speed is accelerated at a large acceleration.

  In this embodiment, since the supply port 16 for the coating liquid is provided in the center with respect to the longitudinal direction of the base 11, the discharge amount is the largest at the central portion in the longitudinal direction of the discharge port 13 and the discharge amount is the smallest at the end portion. Tend. This tendency also affects the film thickness distribution of the coating film 14, and when the coating liquid is discharged at a constant speed as shown in FIG. 4A, the difference Δt between the thickest part and the thin part is the smallest. As shown in FIGS. 4B and 4C, the Δt increases as the acceleration of the discharge amount increases.

  Accordingly, if the ejection speed is accelerated at an acceleration equivalent to the acceleration of the ejection speed in the bead formation process, the difference between the thickest part and the thin part becomes large, and the uniformity of the film thickness deteriorates. The same applies to the case where the ejection speed is accelerated in one stage with a large acceleration as shown in FIG. 8 and the vehicle enters above the accuracy required region R2 until the acceleration is completed.

  Therefore, in the acceleration step of this embodiment, the control means 4 controls the discharge speed to be such that Δt is smaller than the film thickness accuracy of the coating film 14 required in the accuracy required region R2. Accelerating.

  Here, in the present embodiment, as shown in FIG. 3B, the discharge port 13 of the base 11 is already located above the accuracy required region R2 at the time t4, which is the end time of the acceleration process. The film thickness accuracy of the coating film 14 applied in the acceleration process must satisfy the film thickness accuracy of the coating film 14 required in the accuracy request region R2. On the other hand, in the acceleration process of the present embodiment, the discharge speed and the transport speed are accelerated with a small acceleration as described above, so that the film thickness accuracy of the coating film 14 is the same as the film thickness accuracy required in the accuracy required region R2. Can be satisfied.

  Here, before the application to the substrate W is performed by the coating apparatus 1, data on the change in the film thickness accuracy in the longitudinal direction of the discharge port 13 with respect to the change in the acceleration of the discharge speed is collected in advance, and based on this data, It is desirable that the upper limit value of the ejection speed acceleration that can satisfy the predetermined film thickness accuracy is grasped in advance, and the ejection speed acceleration during the acceleration process is determined based on the upper limit value.

  Note that the data on the upper limit value of the acceleration of the discharge speed may be recorded in the control unit 4 in advance. And the control means 4 may determine automatically the acceleration of the discharge speed in an acceleration process so that it may become an acceleration below this upper limit. Further, when the user manually sets, the user may be guided to input a value equal to or lower than the upper limit value by outputting an error when the user tries to input an acceleration value exceeding the upper limit value.

  As described above, the bead formation process and the acceleration process are provided and the coating operation is performed, so that the required film thickness accuracy can be satisfied over the entire accuracy-required region R2.

  In the present embodiment, the discharge speed and the conveyance speed are set to the first time between time t1 and time t3 shown in FIG. 3A, that is, between the completion of the bead formation process and the start of the acceleration process. A step of maintaining the discharge speed P1 and the first moving speed for a predetermined time is provided. This process is called a stabilization process in the present invention.

  By providing this stabilization process, even if an overshoot occurs in the discharge amount of the coating liquid at the end of the bead formation process, the overshoot can converge and the process can proceed to the acceleration process. It is possible to keep the film thickness of the coating solution more constant.

  In addition, when there is no concern that an overshoot of the discharge amount of the coating liquid occurs at the end of the bead formation process, the stabilization process may be omitted and the acceleration process may be started immediately after the bead formation process is completed.

  Here, in the present embodiment, a stabilization process is provided as shown in FIG. 3A, and the acceleration process starts from time t3, which is a time after time t2. That is, the acceleration process is started after the discharge port 13 of the base 11 is located above the accuracy requirement region R2, but the acceleration process is performed within the time when the discharge port 13 is located above the accuracy requirement exclusion region R1. May start.

  In addition, it is desirable that the ejection speed and the transport speed in the acceleration process are S-shaped acceleration as shown in FIG. That is, it is desirable that the acceleration at the start of acceleration (near time t3 in FIG. 3 (a)) and at the end of acceleration (near time t4 in FIG. 3 (a)) is even smaller than the acceleration at the time between them. This prevents sudden changes in acceleration, prevents overshooting of the discharge rate of the coating liquid and prevents film thickness accuracy from deteriorating, and accelerates the discharge speed and transport speed without making the bead unstable. It is possible to make it.

  Similarly, the acceleration form of the discharge speed and the conveyance speed in the bead formation process may be S-shaped acceleration.

  Next, a method for controlling the ejection speed and the conveyance speed in another embodiment will be described.

  In the embodiment shown in FIG. 5, the control means 4 controls the application amount of the coating liquid per unit area on the substrate W to be constant by delaying the timing of the ejection speed acceleration with respect to the acceleration of the transport speed. This is an example.

  5 (a) and 5 (b) are schematic diagrams of the bead 15, and the ratio of the discharge speed and the transport speed (discharge speed / transport speed) is the same in both figures, but FIG. When the speed and the transport speed are low, FIG. 5B shows the case where the discharge speed and the transport speed are high.

  As shown in FIGS. 5A and 5B, the volume of the bead 15 decreases as the discharge speed (transport speed) increases even if the ratio between the discharge speed and the transport speed is the same. This is considered to be due to factors such as the force that the base 11 and the substrate W pull the bead 15 increases as the transport speed is accelerated.

  Here, when accelerating the discharge speed and the transport speed in the acceleration step, the volume of the bead 15 becomes smaller as described above along with the acceleration. Then, the coating liquid corresponding to the reduced volume of the bead 15 is reduced to the coating film 14. As the coating liquid is reduced to the coating film 14 in this way, the film thickness of the coating film 14 becomes thicker than the film thickness calculated from the ratio between the discharge speed and the transport speed.

  Therefore, in particular, when applying a coating solution in which the volume of the bead 15 changes significantly due to changes in the discharge speed and the transport speed, the application liquid is applied to the substrate per unit area after reflecting the reduction in the acceleration step. The control means 4 controls the discharge speed and the conveyance speed so that the amount becomes constant.

  Specifically, as shown in FIG. 5C, the control unit 4 sets the acceleration start time of the discharge speed to a time t3 that is slightly later than the acceleration start time t3 of the transport speed, and moves to the coating film 14 in the acceleration process. In consideration of the amount that the coating solution is reduced, the coating amount per unit area on the substrate W is reduced.

  According to the coating method and the coating apparatus described above, it is possible to apply the coating liquid with high accuracy and in a short time on the entire surface of the region where film thickness accuracy is required.

  In this embodiment, after performing the bead formation process, the discharge speed and the conveyance speed are accelerated to the maximum speed in one acceleration process, but the maximum speed is reached through a multi-stage acceleration process. Also good.

DESCRIPTION OF SYMBOLS 1 Application | coating apparatus 2 Application | coating means 3 Relative movement means 4 Control means 11 Base 12 Lip 13 Discharge port 14 Coating film 15 Bead 16 Supply port 21 Placement part 90 Coating apparatus 91 Base 92 Relative movement means R1 Accuracy requirement exclusion area | region R2 Accuracy requirement area | region W substrate

Claims (4)

A nozzle having a slit-like discharge port that is long in one direction, and discharging a coating liquid from the discharge port;
Relative moving means for relatively moving the base and the substrate in the short direction of the discharge port;
Control means for controlling the discharge speed of the coating liquid discharged from the discharge port and the relative movement speed by the relative movement means;
A substrate having an accuracy requirement exclusion region that does not require the film thickness accuracy of the coating film on the outer peripheral portion, and an accuracy requirement region that requires the film thickness accuracy inside the accuracy requirement exclusion region. On the other hand, a coating method for forming a coating film by discharging a coating liquid from the discharge port while relatively moving the base by the relative movement means,
A starting step in which the control means starts the discharge of the coating liquid from the discharge port and the relative movement in a state where the discharge port is located above the accuracy requirement exclusion region;
The control means determines the discharge speed and the relative movement speed of the coating liquid from the discharge port between the base and the substrate within the time when the discharge port is located above the accuracy requirement exclusion region. A bead forming step of accelerating to a first discharge speed and a first movement speed capable of maintaining the bead according to
After the bead forming step, the control means is smaller than the ejection speed and the relative movement speed acceleration in the bead forming step, and occurs in the longitudinal direction of the ejection port due to the acceleration of the ejection speed. The discharge speed is adjusted while maintaining the application amount of the coating liquid per unit area on the substrate at an acceleration at which the film thickness error is within the range of the film thickness accuracy required for the coating film. Accelerating to a second discharge speed higher than one discharge speed, and accelerating the relative movement speed to a second movement speed higher than the first movement speed , and
A stabilization step of performing application to the substrate between the bead formation step and the acceleration step while maintaining the discharge speed and the relative movement speed at the first discharge speed and the first movement speed for a predetermined time; A coating method, comprising: In the acceleration step, the control means controls the application amount of the coating liquid per unit area on the substrate to be constant by delaying the timing of the ejection speed acceleration with respect to the acceleration of the relative movement speed. The coating method according to claim 1, wherein: The acceleration mode of the discharge speed and the relative speed in the acceleration process is characterized by an S-curve acceleration, The coating method according to any one of claims 1 to 2. A nozzle having a slit-like discharge port that is long in one direction, and discharging a coating liquid from the discharge port;
Relative moving means for relatively moving the base and the substrate in the short direction of the discharge port;
Control means for controlling the discharge speed of the coating liquid discharged from the discharge port and the relative movement speed by the relative movement means;
A substrate having an accuracy requirement exclusion region that does not require film thickness accuracy of the coating film on the outer peripheral portion, and an accuracy requirement region that requires film thickness accuracy inside the accuracy requirement exclusion region. A coating apparatus that forms a coating film by discharging a coating liquid from the discharge port while relatively moving the base by a relative movement unit,
A start mode in which the control means starts discharge of the coating liquid from the discharge port and the relative movement in a state where the discharge port is positioned above the accuracy requirement exclusion region;
The control means determines the discharge speed and the relative movement speed of the coating liquid from the discharge port between the base and the substrate within the time when the discharge port is located above the accuracy requirement exclusion region. A bead formation mode for accelerating to a first discharge speed and a first movement speed capable of maintaining the bead according to
After the bead formation mode, the control means is smaller than the ejection speed and the relative movement speed in the bead formation process, and occurs in the longitudinal direction of the ejection port due to the acceleration of the ejection speed. The discharge speed is adjusted while maintaining the application amount of the coating liquid per unit area on the substrate at an acceleration at which the film thickness error is within the range of the film thickness accuracy required for the coating film. Accelerating to a second discharge speed that is faster than one discharge speed, and accelerating the relative movement speed to a second movement speed that is faster than the first movement speed ; and
Between the bead formation mode and the acceleration mode, a stabilization mode in which coating is performed on the substrate while maintaining the discharge speed and the relative movement speed at the first discharge speed and the first movement speed for a predetermined time. A coating apparatus, comprising:

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