JP4742511B2 - Coating method, coating apparatus, and display member manufacturing method - Google Patents

Description

  The present invention is used in the field of manufacturing color filters for color liquid crystal displays, array substrates for TFTs, optical filters, printed circuit boards, integrated circuits, semiconductors, and the like. The present invention relates to an improvement of a coating apparatus and a coating method for forming a coating film while discharging a coating liquid, and a method for manufacturing a display member such as a color filter or a TFT array substrate using these apparatuses and methods.

  A color filter for a color liquid crystal display has a fine lattice pattern of three primary colors on a glass substrate. Such a lattice pattern forms red, blue and green after forming a black coating on the glass substrate. In this way, the coating film is formed in three primary colors on the glass substrate.

  Therefore, for the production of a color filter, a forming process is required in which black, red, blue, and green coating liquids are sequentially applied onto a glass substrate to form the coating film. In this type of forming process, spinners can be used to form uniform coatings easily, and recently they have been used. However, recently, the consumption of expensive coating solutions has been reduced, and glass with a width exceeding 1 m. Along with the increase in size of the device corresponding to the substrate, a large number of die coaters have been introduced.

  As an example of this type of die coater, a reciprocable table and a coating head (die) having a downward discharge port are provided, and after the glass substrate is adsorbed and held on the table, the glass substrate is used together with the table. However, there is a technique in which a coating liquid is discharged from a discharge port of a coating head as the coating head moves directly below, and a coating film is continuously formed on a glass substrate (for example, Patent Document 1).

  In recent years, as the quality of products has improved, the accuracy of film thickness distribution required for die coaters to be applied to substrates has been increasing. For example, film thickness unevenness of ± 3% or less excluding the 10 mm edge. It is hoped to do.

  In general, large film thickness fluctuation occurs not in the coating direction and the substrate width direction, which is the longitudinal direction of the die, but in the end portion, not the central portion. For the end in the width direction, since the film thickness profile of the coating film is determined by the characteristics of the coating liquid, the adjustment of the characteristics of the coating liquid is the main improvement means. On the other hand, regarding the end portion in the coating direction, the quality control of the coating start portion and the coating end portion greatly affects the film thickness profile formation that minimizes the defective film thickness section that does not reach the target film thickness range. Therefore, many improvement means for shortening the defective film thickness section and increasing the uniform film thickness section have been proposed.

For the coating start part, in order to prevent the film from becoming thicker, a clearance between the substrate and the die is controlled in conjunction with the discharge of the coating liquid and the horizontal movement of the die with respect to the substrate (for example, a patent) Reference 2), there is a method (for example, Patent Document 3 ) in which the substrate is kept stationary, and the movement of the substrate is started after a predetermined time after the pump is driven to start discharging.
JP-A-6-339656 (5th column 18th line to 7th column 25th line, 10th column 9th line to 43rd line, FIG. 1) JP 2002-113411 A (column 4, line 48 to column 5, line 24, column 9, line 3 to line 31, FIGS. 1 and 5) JP-A-8-229482 (column 13, line 46 to column 15, line 48, FIG. 3)

  The film thickness profile control means at the application start part can change the film thickness profile by changing the parameters. However, even if the parameters are changed in the smallest unit possible on the apparatus, the change in the film thickness profile is so large that the desired film thickness profile cannot be adjusted sufficiently. There is a problem that a defective film thickness section that does not reach the film thickness range is lengthened and a uniform film thickness section is shortened.

  The present invention has been made based on the above-mentioned circumstances, and its object is to indicate means capable of finely adjusting the film thickness profile of the coating film at the coating start part, and to provide a target film thickness generated at the coating start part. Minimizing the defective film thickness section that does not reach the range, thereby making the uniform film thickness section the longest and maximizing the effective product area on a single coated material at low cost and easily Another object of the present invention is to provide a coating apparatus and method that can be used, and a method for manufacturing a display member using this method.

  The above object is achieved by the means described below.

In the coating method of the present invention, an applicator having a discharge port extending in one direction is brought close to a member to be coated, and a coating liquid having a viscosity of 1 to 50 mPaS is supplied from the constant capacity pump to the coating device. In the coating method in which the coating liquid is discharged from the coating member and the coated member is moved relative to the coating device to form a coating film on the coated member, the constant-capacity pump is applied to the coating device under the same conditions as in the coating. Repeat the preliminary test to detect the pressure at the time of application in the route to reach, and obtain the film thickness that targets the operating speed of the mechanical drive part of the constant capacity pump so that the detected pressure waveform shape becomes the desired shape when launching to reach operating speed for, for each short arbitrary time intervals than the startup time of the pressure waveform, defining the parameters by performing varied to reach the operating speed undershooting In, characterized in that the actual application by controlling the pressure.

Here, the control of the pressure is preferably performed by providing an orifice having a variable shape between the constant capacity pump and the applicator and changing the shape of the orifice.

The coating apparatus of the present invention holds a coating member having a discharge port extending in one direction for discharging a coating solution, a constant capacity pump for supplying a coating solution having a viscosity of 1 to 50 mPaS to the coating device, and a member to be coated. And a moving means for relatively moving at least one of the applicator and the mounting table, and a proximity means for bringing the applicator close to the member to be coated to form a coating film on the member to be coated. In addition, a pressure detector is provided in a path from the constant-capacity pump to the applicator, and a pressure waveform shape detected by the pressure detector in a preliminary test under the same conditions as in the application is desired. Every time interval shorter than the rise time of the pressure waveform when starting up to reach the operating speed to obtain the target film thickness, so that the operating speed of the mechanical drive part of the constant capacity pump becomes a shape In addition, By performing varied to reach the operation speed undershoot defining the parameters, characterized by comprising a pressure controller for controlling the pressure of the actual coating.

Here, it is preferable to provide an orifice having a variable shape between the constant capacity pump and the applicator as the pressure control device .

The manufacturing method of the display member of the present invention is characterized in that the display member is manufactured using the coating method of the present invention .

If the coating method and the coating apparatus according to the present invention are used, the preliminary test for detecting the pressure at the time of application in the path from the constant-capacity pump to the applicator in advance under the same conditions as at the time of application is repeated, and the detected pressure waveform shape After determining each parameter by changing the operation speed of the mechanical drive unit of the constant displacement pump at an arbitrary time interval shorter than the rise time of the pressure waveform so that the pressure becomes the desired shape, By controlling and actually applying, the film thickness profile of the application start portion can be finely adjusted . Therefore, it is possible to easily obtain a film thickness profile shape that minimizes the defective film thickness section that does not reach the target film thickness range generated in the coating start portion, and thereby maximizes the uniform film thickness section. As a result, a coating film having high film thickness distribution accuracy can be obtained, and the effective product area on one coated member can be maximized.

  According to the method for manufacturing a display member according to the present invention, the display member is manufactured using the above-described excellent coating method. Can be manufactured.

  Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

  The application method of the present invention detects the pressure at the time of application in the path from the constant capacity pump to the applicator so that the detected pressure waveform shape becomes a desired shape at least at the application start part. Application is carried out by controlling the pressure. Here, the application start portion refers to a transition interval from the start of application until the coating film thickness reaches a target constant film thickness from zero, that is, the above-described defective film thickness interval. Moreover, the desired pressure waveform shape at the application start portion indicates that the pressure has reached a predetermined value from zero within a predetermined start-up time. Furthermore, it is preferable to shorten the startup time in order to minimize the defective film thickness section.

  Therefore, when carrying out the method of the present invention, after repeating the preliminary test to detect the pressure waveform shape under the same conditions as the application in advance, and after determining each parameter so that the pressure waveform shape becomes a desired one, The actual application is performed.

  FIG. 1 is a schematic front sectional view of a die coater 1 which is a coating apparatus for performing a coating method according to the present invention, and FIG. 2 is a time line diagram showing a relationship among a film thickness, a syringe pump coating liquid supply speed, and a substrate A moving speed. FIG. 3 is a time diagram showing the relationship between the pressure at the application start portion and the piston operating speed, FIG. 6 is a time diagram of another pressure and piston machine operating speed, and FIG. 7 is still another pressure and piston machine operating speed. FIG.

  Referring first to FIG. 1, a die coater 1 of the present invention is shown. The die coater 1 includes a base 2, and a pair of guide rails 4 are provided on the base 2. On the guide rail 4, a mounting table for the substrate A as a member to be coated, that is, a stage 6 is arranged. The stage 6 is driven by a linear motor (not shown) and reciprocates freely in the X direction indicated by an arrow in FIG. The upper surface of the stage 6 is a vacuum suction surface made of suction holes, and can hold the substrate A by suction.

  Looking at the center of the base 2, there is a gate-shaped column 10. On both sides of the support column 10, an up-and-down lift unit 70 is provided, and a die 20 that performs coating is attached to the up-and-down lift unit 70.

  The die 20 includes a front lip 22 and a rear lip 24 that extend in a direction perpendicular to the X direction (a direction perpendicular to the paper surface), overlapped in the X direction via shims 32, and are integrally formed by a plurality of connection bolts (not shown). Are combined. A manifold 26 is formed at the center of the die 20, and this manifold 26 also extends in the longitudinal direction of the die 20 (direction orthogonal to the X direction). A slit 28 is formed below the manifold 26 so as to communicate therewith. The slit 28 also extends in the longitudinal direction of the die 20, and the lower end thereof becomes an opening at the discharge port surface 36 that is the lowest end surface of the die 20, thereby forming the discharge port 34. Since the slit 28 is formed by the shim 32, the slit gap (measured in the X direction) is equal to the thickness of the shim 32.

  The vertical lifting / lowering device unit 70 that lifts and lowers the die 20 includes a suspension holding base 80 that holds the die 20 in a suspended form, a lifting base 78 that lifts and lowers the suspension holding base 80, and a guide that guides the lifting base 78 in the vertical direction. 74, and a ball screw 76 that converts the rotational motion of the motor 72 into the linear motion of the lifting platform 78. The vertical lift unit 70 has a pair of left and right so as to support both ends of the die 20 in the longitudinal direction, and each can be lifted and lowered independently, so that the tilt angle with respect to the horizontal in the longitudinal direction of the die 20 can be arbitrarily set. Thereby, the discharge port surface 36 of the die 20 and the substrate A can be made substantially parallel over the longitudinal direction of the die 20. Further, the vertical lift unit 70 can provide a clearance, that is, a clearance of any size between the substrate A on the stage 6 and the discharge port surface 36 of the die 20.

  Further, when the right end portion of the base 2 is viewed in FIG. 1, the wiping unit 90 is mounted on the guide rail 4 so as to be movable in the X direction. In the wiping unit 90, a wiping head 92 having a shape that engages with the periphery of the discharge port 34 of the die 20 is attached to the slider 96 via a bracket 94. The slider 96 is freely moved by the drive unit 98 in the longitudinal direction of the die 20, that is, in a direction orthogonal to the X direction. The drive unit 98 and the tray 100 are fixed on the carriage 102. Since the carriage 102 is on the guide rail 4 and is guided by the guide rail 4 and can freely reciprocate in the X direction by a linear motor (not shown), the entire wiping unit 90 can reciprocate in the X direction. When wiping is performed, the entire wiping unit 90 is moved in the X direction to a position where the wiping head 92 is engaged with the die 20, and the die 20 is lowered and engaged with the wiping head 92. When the driving unit 98 is driven to slide the wiping head 92 in the longitudinal direction of the die 20, the coating liquid and other contaminants remaining in the vicinity of the discharge port 34 of the die 20 can be removed and cleaned. . The removed coating liquid and the like are collected in the tray 100. The tray 100 is connected to a discharge line (not shown) and can discharge and collect a liquid such as a coating liquid accumulated inside. The tray 100 can also be used for collecting a coating solution discharged from the die 20 by air bleeding or the like. The wiping head 92 is preferably an elastic body such as rubber or a synthetic resin so that it can be engaged with the die 20 evenly.

  Further, when viewing the left side of the base 2, a thickness sensor 120 for measuring the thickness of the substrate A is attached to the support base 122. The thickness sensor 120 preferably uses a laser. By measuring the thickness of the substrate A with the thickness sensor 120, the clearance that is the gap between the discharge port surface 36 of the die 20 and the substrate A is always constant for the substrate A of any thickness. be able to.

  Looking again at the die 20, the upstream side of the manifold 26 of the die 20 is always connected to a supply hose 60 connected to the coating liquid supply device 40 via an internal passage (not shown). The coating liquid can be supplied from the coating liquid supply apparatus 40. The coating liquid that has entered the manifold 26 is uniformly widened in the longitudinal direction of the die 20 and is discharged from the discharge port 34 through the slit 28. A bead B that is a liquid pool is formed between the discharge port surface 36 and the substrate A, and then a coating film C is formed on the substrate A.

  In addition, the coating liquid supply device 40 has a filter 46, a throttle valve 47, a pressure gauge 48 as a pressure detector, a supply valve 42, a syringe pump 50, a suction valve 44, a suction hose 62, and a tank upstream of the supply hose 60. 64. The throttle valve 47 may be any needle type, ball type, diaphragm type, bellows type or the like that can form an orifice and generate a pressure difference, and the orifice shape is variable depending on the opening and the pressure difference can be arbitrarily set. It may be a thing. That is, if the orifice opening is reduced, the orifice shape, that is, the cross-sectional area is reduced, so the pressure difference increases. Conversely, if the orifice opening is increased, the orifice shape, that is, the cross-sectional area, is increased, so the pressure difference is reduced. Become. Now, a coating liquid 66 is stored in the tank 64, and it can be connected to a pressurized air source 68 to apply a back pressure of any size to the coating liquid 66. The coating liquid 66 in the tank 64 is supplied to the syringe pump 50 through the suction hose 62. In the syringe pump 50, a syringe 52 and a piston 54 are attached to a pump main body 56. Here, the piston 54 can reciprocate freely in the vertical direction by a drive source (not shown). The syringe pump 50 is a constant capacity type pump that fills a syringe 52 having a constant inner diameter with a coating liquid, pushes it out by a piston 54, and supplies a single substrate A to the die 20. Although the syringe 52 of the syringe pump 50 is stationary, the piston 54 moves up and down, so that it becomes a mechanical drive unit. The application liquid supply speed from the syringe pump 50 to the die 20 is determined by the operation speed of the piston 54 that is the machine drive unit, that is, the rising movement speed that is the machine operation speed. Then, when filling the application liquid 66 into the syringe 52, the suction valve 44 is opened, the supply valve 42 is closed, and the piston 54 is moved downward. When supplying the coating liquid filled in the syringe 52 toward the die 20, the suction valve 44 is closed, the supply valve 42 is opened, and the piston 54 is moved upward so that the piston 54 moves inside the syringe 52. The coating liquid is pushed up and discharged. In the syringe pump 50, it is preferable that an O-ring (not shown) is attached to the piston 54 or the syringe 52 as a sealing material in order to provide airtightness between the male-side piston 54 and the female-side syringe 52. The pressure when the coating liquid is supplied to the die 20 from the syringe pump 50 is measured by the pressure gauge 48. The pressure gauge may be installed at any position as long as it is in the path from the constant capacity pump to the applicator, that is, in the path from the syringe pump 50 to the die 20. Since the magnitude of the pressure acting on the syringe pump 50 when supplying the coating liquid from the syringe pump 50 to the die 20 can be adjusted by adjusting the opening of the orifice of the throttle valve 47, the throttle valve 47 is used as a pressure control device. Has the role of As described above, when the opening degree of the orifice of the throttle valve 47 is decreased, the shape of the orifice, that is, the cross-sectional area is decreased. Therefore, the pressure difference when the coating liquid passes through the orifice is increased, and the pressure acting on the syringe pump 50 is growing. On the contrary, when the opening of the orifice is increased, the shape of the orifice, that is, the cross-sectional area is increased. Therefore, the pressure difference when the coating liquid passes through the orifice is decreased, and the pressure acting on the syringe pump 50 is decreased. When the supply hose 60 from the syringe pump 50 to the die 20 is made of resin, if the pressure is large, the supply hose 60 expands and elastically deforms, and the coating liquid is accumulated there until the deformation is completed. Therefore, when the supply of the coating liquid from the syringe pump 50 to the die 20 is started, the pressure gradually increases and the supply hose 60 expands and deforms, and the coating liquid is accumulated in the supply hose 60 by the amount of expansion deformation. However, since the coating liquid is not supplied to the die 20 until the accumulation is completed, the startup time until the coating liquid supply speed from the syringe pump 50 to the die 20 reaches a predetermined value from zero becomes longer. Become. That is, if the pressure acting on the syringe pump 50 by the throttle valve 47 is changed, the startup time also changes accordingly. Therefore, it can be said that the startup time of the application liquid supply speed of the syringe pump 50 can be adjusted by the throttle valve 47.

  Note that the linear motor, the motor 72, the coating liquid supply device 40, and the like that are operated by the control signal are all electrically connected to the control device 130. Then, a control command signal is transmitted to each device in accordance with an automatic operation program incorporated in the control device, and a predetermined operation is performed. When changing the conditions, if an appropriate change parameter is input to the operation panel 132, the change parameter is transmitted to the control device 130, and the change of the driving operation can be realized. In particular, in the coating liquid supply device 40, the pressure gauge 48, the syringe pump 50, the supply valve 42, and the suction valve 44 are electrically connected, and the control device 130 receives the electrical signals and measurement values, An arbitrary operation can be performed in accordance with a command from the control device 130. By using the control device 130, the operations of the coating liquid supply device 40, the up / down lifting unit 70, and the stage 6 can be freely controlled, so that the coating film profile at the coating start portion and the coating end portion can be arbitrarily set. The operation of the part can be controlled.

  An example of control of the actual application start part is shown. FIG. 2 is a time diagram showing the relationship between the coating liquid supply speed of the syringe pump 50, the moving speed of the substrate A adsorbed to the stage 6, and the film thickness of the coating film C applied to the substrate A. As shown in FIG. 2A, the application is performed by first supplying the application liquid from the syringe pump to the stationary substrate A and starting the movement of the substrate A, that is, the stage 6 after a predetermined time t0 seconds. The fixed time t0 seconds is a time spent for supplying the coating liquid between the die 20 and the substrate A to form the bead B. After the substrate A starts moving, a coating film is formed on the substrate A. The thickness, that is, the film thickness, is derived from the moving speed of the substrate A and the coating liquid supply speed from the syringe pump 50. Determined by material balance. When the moving speed of the substrate A and the coating liquid supply speed from the syringe pump 50 reach predetermined constant values Vs and Vp, a coating film having a target film thickness TH is formed on the substrate A. In FIG. 2, the section from the start of application to the target film thickness TH is named the defective film thickness section, and the section reaching the target film thickness TH is named the uniform film thickness section. It is desirable to perform control to maximize the uniform film thickness section. For that purpose, both the time ts until the moving speed of the substrate A reaches a predetermined value Vs determined from zero, and the time tp until the coating liquid supply speed from the syringe pump 50 reaches a predetermined value Vp determined from zero. Minimal control is required. For example, as shown in FIGS. 2B and 2C, it takes time until the coating liquid supply speed from the syringe pump 50 is overshooted and stabilized even when the start-up time ts of the substrate A is short. If the start-up time becomes longer due to slow acceleration, the defective film thickness section becomes longer.

  Next, the coating method of the present invention using the die coater 1 will be described in detail.

  In the coating method of the present invention, in order to minimize the defective film thickness section of the coating start portion shown in FIG. 2A, the coating liquid supply speed from the syringe pump 50 that is a constant capacity pump to the die 20 that is a coating device. Presents means for minimizing the time from when the syringe pump 50 starts to reach a predetermined constant value Vp, that is, the startup time tp.

  The coating liquid supply speed from the syringe pump 50 is proportional to the pressure detected by the pressure gauge 48. That is, measuring the pressure with the pressure gauge 48 is synonymous with measuring the coating liquid supply speed from the syringe pump 50. FIG. 6 is a time diagram of the mechanical operating speed of the piston 54 and the pressure measured at that time. In FIG. 6, the ascending operation speed of the piston 54 of the syringe pump 50, that is, the mechanical operation speed Vpi is obtained so as to obtain a desired application liquid supply speed from the syringe pump 50, and the piston 54 is driven at a constant start-up time tpi. Yes. At this time, the pressure waveform generated by the coating liquid supplied from the syringe pump 50 is measured by the pressure gauge 48, but does not correspond to the mechanical operation speed waveform of the piston 54. That is, the piston 54 reaches a predetermined constant speed Vsi at time tpi, whereas the pressure, that is, the actual coating liquid supply speed reaches a constant value P at a longer time tpr. . In other words, the pressure rise time tpr is longer than the piston 54 rise time tpi. This is due to the internal pressure of the supply hose 60 made of a resin tube between the syringe pump 50 and the die 20 even if the coating liquid is sent from the syringe pump 50 at a coating liquid supply speed corresponding to the operating speed of the piston 54. This is because the coating liquid is accumulated therein due to deformation, compression deformation of the mixed air, etc., and the coating liquid is temporarily not supplied to the die 20, causing a delay.

  Therefore, in the coating method of the present invention, the coating liquid is supplied from the syringe pump 50 to the die 20 under the same conditions as in the coating in advance, the pressure is measured by the pressure gauge 48, and the pressure waveform becomes a desired shape. The operating conditions of the piston 54 are determined.

  Here, the desired pressure waveform shape means that the pressure has risen from the start of application at a predetermined rising time, that is, reaches a predetermined pressure value. The pressure rising time tpr is made the same as or shorter than the rising time ts of the stage 6. As shown in FIG. 2, when the rise time tp of the coating liquid supply speed from the syringe pump 50 is made shorter than the rise time ts of the substrate A, that is, the stage 6, the time to reach the target film thickness TH. This is because it does not become longer than the startup time of the stage 6, that is, the defective film thickness section can be minimized.

  A method for determining the operating condition of the piston 54 so that the pressure waveform measured by the pressure gauge 48 has a desired shape will be described with reference to FIG.

  First, the piston 54 of the syringe pump 50 is operated under the same conditions as in actual application, that is, as shown by the broken line in FIG. 3A, at the rising time tpi and the arrival speed Vpi2, and the pressure waveform is as shown by the broken line. Suppose that it was measured. The pressure rises at a time tpr1 much longer than the mechanical operating speed tpi of the piston 54. Therefore, as shown by the solid line, the piston 54 reaches the speeds Vpi1 and Vpi2 at time intervals t1 and t2 shorter than the start-up time tpi, and Vpi1> Vpi2 is set so that the pressure rises in a short time. Here, Vpi2 is the piston 54 machine operating speed for obtaining the target film thickness. By the operation of the piston 54 shown by the solid line, the pressure rises at the target rise time tpi as shown by the solid line and becomes a desired one. Further, as shown by a broken line in FIG. 3B, when the mechanical operation speed of the piston 54 of the syringe pump 50 is increased at the time tpi, the pressure overshoots, and the time tpr1 longer than the mechanical operation speed tpi of the piston 54. As shown by the solid line, the machine operation speeds Vpi1 and Vpi2 of the piston 54 are reached at time intervals t1 and t2. In addition, Vpi1 <Vpi2 is set so as to cancel the pressure overshoot so as to undershoot intentionally. As a result, the pressure rises at the target rise time tpi as shown by a solid line and becomes a desired one.

  In FIG. 3, only two combinations of time intervals t1 and t2 and arrival speeds Vpi1 and Vpi2 are shown, but both may be values exceeding 2. The time intervals may be the same or different, but for ease of adjustment, it is preferable to set the time intervals to two and to have the same value. The actual size of the time interval is preferably 20 to 300 ms, more preferably 50 to 200 ms, since the rise is shortened to reduce the defective film thickness region. Further, when correcting undershoot, Vpi1 / Vpi2 is preferably 1.01 to 5, more preferably 1.1 to 3, and when correcting overshoot, Vpi2 / Vpi1 is preferably 1.01 to 1. 5, more preferably 1.1 to 3. The mechanical operating speeds Vpi1 and Vpi2 of the piston 54 may be derived by giving film thicknesses TH1 and TH2 and converting them.

  Further, as shown by the solid line in FIG. 7, when the piston 54 mechanical operation speed of the syringe pump 50 is raised at the rise time tpi, the pressure overshoots, and when a time tpr1 longer than tpi until reaching a constant is required. This can also be dealt with by appropriately reducing the opening of the orifice of the throttle valve 47, that is, by reducing the shape of the orifice and increasing the pressure acting on the syringe pump 50 from P1 to P2. As a result, the pressure overshoot can be eliminated as shown by the broken line in FIG. 7, and the pressure can be raised to the constant value P2 in the same short time as the rise time tpi of the piston 54 machine operating speed Vpi. The fact that the pressure reaches a constant value P2 at time tpi means that the coating liquid supply speed from the syringe pump 54 to the die 20 reaches a constant value and rises at the same time tpi. The throttle valve 47 can perform such adjustment, that is, control, because the pressure increases as the orifice opening of the throttle valve 47 decreases, so that the supply hose 60, the supply valve 42, the suction valve 44, and the syringe pump made of a resin tube are used. This is due to the effect that the elastic deformation element existing in the coating liquid contact part such as 50 is deformed to act as a buffer, and the coating liquid is accumulated by the amount of deformation, so that the rate of pressure increase is alleviated. In order to eliminate the pressure overshoot using the throttle valve 47, it is important to adjust the opening of the orifice of the throttle valve 47 appropriately while checking the pressure waveform with the pressure gauge 47.

  Next, the coating method when applying the above coating method to the single wafer coating in the die coater 1 will be described in detail.

  First, when the origin return of each operation unit of the die coater 1 is performed, each moving unit moves to the standby position. That is, the stage 6 moves to the left end of FIG. 1 (a position indicated by a broken line), the die 20 moves to the top, and the wiping unit 90 moves so that the tray 100 is positioned below the die 20. Here, the coating liquid 66 is already filled from the tank 64 to the die 20, and the operation of discharging the residual air inside the die 20 has already been completed. The state of the coating liquid supply device 40 at this time is such that the syringe 52 is filled with the coating liquid 66, the suction valve 44 is closed, the supply valve 42 is opened, and the piston 54 is at the lowermost position. 20 can be supplied. In this state, the piston 54 of the syringe pump 50 is raised at the same machine operating speed as that for application, and the application liquid 66 is supplied to the die 20 and discharged from the die 20 toward the tray 100. Measure. Then, the starting machine operating speed of the piston 54 as shown by the solid line in FIG. 3 is determined so that the measured pressure rising time tp becomes a predetermined value. Until the optimum starting machine operating speed of the piston 54 is obtained, filling of the coating liquid 66 into the syringe pump 50 and supply of the coating liquid 66 to the die 20 are repeated.

  After the above preparatory operation is completed, lift pins (not shown) are raised on the surface of the stage 6, and the substrate A is placed on the lift pins from a loader (not shown). Next, the lift pins are lowered to place the substrate A on the upper surface of the stage 6 and simultaneously hold it by suction. At the same time, the coating liquid supply device 40 is operated to discharge a small amount of the coating liquid 66 toward the tray 100, and then the wiping unit 90 is moved so that the wiping head 92 is positioned just below the discharge port 34 of the die 20. Let Then, the die 20 is lowered and the discharge port surface 36 of the die 20 is engaged with the wiping head 92, and then the wiping head is slid in the longitudinal direction of the die 20 so that the vicinity of the discharge port 34 of the die 20 extends in the longitudinal direction of the die 20 to clean up. After the cleaning is completed, the wiping unit 90 returns to the original place (the right end in FIG. 1).

  When it is confirmed that the wiping unit 90 has moved to the right end of the base 2, the stage 6 on which the substrate A is placed starts to move. At this time, the die 20 is in a wiping position far above the position where the application is performed, while the syringe pump 50 is stopped and waiting. Then, the substrate thickness is measured when the substrate A passes under the thickness sensor 120, and the stage 6 is stopped when the coating start portion of the substrate A reaches just below the discharge port 34 of the die 20. At this time, using the measured thickness data of the substrate A, the vertical lift unit 70 is driven so that the clearance between the discharge port surface 36 of the die 20 and the substrate A, that is, the clearance becomes a predetermined value. Lower. Then, the syringe pump 50 is driven at the machine operating speed of the piston 54 optimized in advance, and the discharge of the coating liquid 66 from the die 20 is started. Then, after the waiting time t seconds, the bead grows to a predetermined size, and then the stage 6 starts to move at a predetermined start-up time ts and a speed Vs, and the application of the coating liquid 66 to the substrate A is started. C is formed. Here, by changing the size of the waiting time t, the film thickness profile of the coating start portion can be adjusted.

  When the position slightly before the application end position of the substrate A comes to the position of the discharge port 34 of the die 20, the piston 54 is stopped and the supply of the application liquid 66 is stopped. At this time, since the stage 6 continues to move at the same speed as in the application, a part of the application liquid remaining between the discharge port surface of the die 20 and the substrate A reaches the application end position on the stage 6. Is transferred to the substrate A as the substrate A moves. When the application end position of the substrate A comes directly below the discharge port 34 of the die 20, the vertical lift unit 70 is driven to raise the die 20. As a result, the bead formed between the substrate A and the die 20 is cut off, and the application is completed.

  In the meantime, the stage 6 continues to operate, stops when it reaches the end point position, releases the suction of the substrate A, raises the lift pins, and lifts the substrate A. At this time, the lower surface of the substrate A is held by an unloader (not shown), and the substrate A is transported to the next step. When the substrate A is delivered to the unloader, the stage 6 lowers the lift pins and returns to the origin position. After returning to the origin position of the stage 6, the wiping unit 90 is moved so that the tray 100 is disposed below the discharge port 34 of the die 20.

  Thereafter, the syringe pump 50 is actuated to feed a small amount of 10 to 500 μL of coating solution into the die 20 and fill the voids remaining inside the die 20 with the coating solution.

  After completion, the suction valve 44 is opened, the supply valve 42 is closed, the piston 54 is lowered, and the application liquid 66 is filled into the syringe 52. After the filling is completed, the piston 54 is stopped, the suction valve 44 is closed, the supply valve 42 is opened, the next substrate A is waited for, and the same operation is repeated.

  In order to obtain a desired pressure waveform shape, the rise time of the pressure, the mechanical operation speed of the piston 54, and the coating liquid supply speed of the syringe pump 50 is preferably 40 to 500 msec, more preferably 100 to 300 msec. In the above-described embodiment, the start-up time is the time from zero to a predetermined value, but may be the time from zero to a range including the predetermined value. The range here is preferably a predetermined value of 0.5 to 10%, more preferably 1 to 5%.

In addition, it is important that the coating liquid applicable to the method and apparatus of the present invention has a viscosity of 1 to 50 mPaS, and a Newtonian is preferable from the viewpoint of coating properties, but it can also be applied to a coating liquid having thixotropy. . In particular, it is effective when a coating solution using a solvent having high volatility such as PGMEA, butyl acetate, ethyl lactate or the like is applied. Specific examples of the coating solution that can be applied include a black matrix for a color filter and a coating solution for forming a color pixel, a resist solution, an overcoat material, and the like. As a member to be coated which is a substrate, a metal plate such as aluminum, a ceramic plate, a silicon wafer or the like may be used in addition to glass. Further, the coating state and coating speed to be used are 0.1 m / min to 10 m / min, more preferably 0.5 m / min to 6 m / min, the die lip gap is 50 to 1000 μm, more preferably 80 to 200 μm, and the coating thickness. Is 1 to 50 μm, more preferably 2 to 20 μm in a wet state.

Example 1
A non-alkali glass substrate having a thickness of 370 × 470 mm and a thickness of 0.7 mm was washed and then coated using the die coater 1. The die has a discharge port length of 370 mm, a discharge port surface length of 0.5 mm, a slit gap of 100 μm, and can form a coating film having a width of 370 mm on a substrate, with a coating speed of 100 mm. / S. A syringe pump 50 having an inner diameter of φ16 mm was used. The coating solution was a positive resist used in the production of liquid crystal TFTs, and had a solid content concentration of 23% and a viscosity of 10 mPaS. The operating speed of the piston 52 of the syringe pump 50 was set to 1.2 mm / s so that the thickness after vacuum drying was 1.5 μm. First, the die 20 was brought close to the application start portion of the stopped substrate, and the clearance between the discharge port surface 36 of the die 20 and the substrate was set to 100 μm. After the clearance was set, the piston 54 started to operate at 1.2 mm / s. Then, after the waiting time t = 0.1 seconds from the start of the piston operation, the operation of the stage 6 is also started to perform coating, and the discharge port 34 of the die 20 comes to the position of the 465 mm glass substrate from the substrate end (coating start position). The syringe pump 50 was stopped. Thereafter, when the glass substrate position of 470 mm from the edge of the substrate came directly below the discharge port 34, the die 20 was pulled up to finish coating. After the above application, vacuum drying with an ultimate vacuum of 65 Pa was performed in 27 seconds. The film thickness distribution in the coating direction was measured with a light interference type film thickness meter, and the film thickness distribution indicated by the broken line in FIG. 4 was obtained. The film thickness accuracy U at this time was calculated by U = (maximum value−minimum value) / (2 × average value) in a region excluding the end 10 mm, and a value of 3.4% was obtained. The target is less than 3%, and when the film thickness distribution is viewed, the coating start portion has a considerable undershoot as shown by the broken line in FIG. When the pressure at the start of application was measured with the pressure gauge 48, as shown by the broken line in FIG. 5 (a), the start portion had an undershoot similar to the film thickness distribution. The operating speed of the piston of the syringe pump 50 was controlled as shown by the broken line in FIG. 5B, but in order to eliminate the undershoot at the start of the pressure, as shown by the solid line in FIG. The piston speed is set to 1.8 mm / s, which is 1.5 times larger than the piston speed of 1.2 mm / s when the target film thickness is applied, after 0.1 second from the start of the operation. After 2 seconds, the piston speed was adjusted to 1.2 mm / s when applying the target film thickness. First, when the pressure was measured, it became as shown by the solid line in FIG. 5A, and the undershoot was eliminated. The coating was applied again with the same piston operating speed pattern, and the film thickness distribution was measured in the same manner as in Example 1 after vacuum drying. As a result, the undershoot was eliminated and the film thickness accuracy U was shown in FIG. Also, excluding the end 10mm, it was 2.5%, achieving the target of 3% or less.
Example 2
A color filter was manufactured using the die coater 1.

  The die had a length in the longitudinal direction of the ejection port of 360 mm, a length in the coating direction of the ejection port surface of 0.5 mm, a gap of the slit of 100 μm, and a coating film having a width of 360 mm could be formed on the substrate.

  First, after cleaning an alkali-free glass substrate having a thickness of 360 mm × 465 mm and a thickness of 0.7 mm, a black matrix coating solution was applied at a thickness of 10 μm and a clearance of 100 μm between the die and the substrate at 3 m / min. Coating is performed by wiping the vicinity of the die discharge port with silicon rubber having the same shape as the discharge port shape, and then bringing the die close to the coating start portion of the substrate with 100 μm clearance, and a coating solution corresponding to a wet thickness of 10 μm. Was sent from a syringe pump, and the movement of the substrate A was started 0.08 seconds after the start of pumping. In addition, when the application liquid was supplied from the syringe pump to the die under the same conditions as the application in advance and the pressure was measured with the pressure gauge 48, it was 10 kPa, and further, an overshoot of pressure was observed at the discharge start part. The opening of the 47 orifice was reduced so that the pressure was 100 kPa. This eliminated the pressure overshoot and confirmed that the pressure reached a constant value in 0.2 seconds, so application to the product was started. In order to finish the application, when the die reaches a position 5 mm from the application end position, the discharge of the application liquid from the syringe pump is ended, and when the die reaches the application end position, the die is moved at a speed of 3 m / min. We also raised it. At this time, the coated black matrix coating solution was made of a photosensitive material in which titanic acid nitride was used as a light shielding material, acrylic resin was used as a binder, and PGMEA was used as a solvent, and the solid content concentration was adjusted to 10% and the viscosity was adjusted to 10 mPaS. A thing was used. The tact time for coating was 30 seconds. The coated substrate was vacuum dried to reach 65 Pa in 30 seconds for 60 seconds, and further dried on a 100 ° C. hot plate for 10 minutes. Next, after performing exposure, development, and peeling, the substrate is heated on a hot plate at 260 degrees for 30 minutes to cure, and the pitch is 254 μm in the width direction of the substrate, the pitch is 85 μm in the longitudinal direction of the substrate, the line width is 20 μm, The number of RGB pixels is 4800 (substrate longitudinal direction) × 1200 (substrate width direction), the diagonal length is 20 inches (305 mm in the substrate width direction, 406 mm in the substrate longitudinal direction), and the thickness is 1 μm. A black matrix film was prepared. In addition, when the coating thickness was measured before forming the lattice pattern of the substrate coated on the first sheet, it was unevenness of ± 3% or less in both the substrate running direction and the width direction except for 10 mm at the end.

  Next, after wet cleaning, an R color coating solution was applied at a thickness of 20 μm, a clearance between the die and the substrate of 100 μm, a discharge speed of 360 mCC / s, and a stage moving speed of 3 m / min. The coating solution for R color was a photosensitive solution prepared by mixing an acrylic resin as a binder, PGMEA as a solvent, and Pigment Red 177 as a pigment, mixing them at a solid concentration of 10%, and adjusting the viscosity to 5 mPaS. The coated substrate was vacuum-dried to reach 65 Pa in 30 seconds for 60 seconds, and further dried on a 90 ° C. hot plate for 10 minutes. Next, exposure, development, and peeling were performed to leave an R-color coating film having a thickness of 2 μm only in the R pixel portion, and curing was performed by heating on a 260 ° C. hot plate for 30 minutes. Subsequently, on the substrate on which the black matrix and the R color coating film are formed, the coating solution for G color is 20 μm thick, the clearance between the die and the substrate is 100 μm, the discharge speed is 360 mCC / s, and the stage moving speed is 3 m / min. After coating, vacuum drying was performed to reach 65 Pa in 30 seconds for 60 seconds, followed by further drying for 10 minutes on a 100 ° C. hot plate. Next, exposure, development, and peeling were performed to leave a G-color coating film having a thickness of 2 μm only on the G-color pixel portion, and curing was performed by heating on a 260-degree hot plate for 30 minutes. Furthermore, on the substrate on which the black matrix, R color, and G color coating films are formed, the coating solution for B color is 20 μm thick, the clearance between the die and the substrate is 100 μm, the pump discharge speed is 360 mCC / s, and the stage moving speed is 3 m. The coating was applied at a rate of 50 minutes per minute, and vacuum drying was performed for 60 seconds to reach 65 Pa in 30 seconds, followed by further drying for 10 minutes on a hot plate at 100 ° C. Next, exposure, development, and peeling were performed to leave a 2 μm-thick B-color coating film only on the B-color pixel portion, and curing was performed by heating on a 260 ° C. hot plate for 30 minutes. The G-color coating solution is an R-color coating solution and the pigment is Pigment Green 36 and the viscosity is adjusted to 10 mPaS at a solid content concentration of 10%. The B-color coating solution is an R-color coating solution. Pigment Blue 15 having a solid concentration of 10% and a viscosity adjusted to 10 mPaS. All of the R, G, and B color coating solutions are applied by wiping the vicinity of the die outlet with silicon rubber, and then approaching the coating start portion of the substrate where the die is stopped with a clearance of 100 μm, and a wet thickness of 20 μm. The coating solution corresponding to was sent from the syringe pump, and the movement of the substrate A was started 0.13 seconds after the pumping was started. In both cases, the discharge of the coating liquid was finished 6 mm before the application end position, and the die was raised at the application end position to complete the application. The tact time for coating was 30 seconds. The coating quality was satisfactory. The film thickness distribution was also measured for each color after drying. The film thickness distribution was good with a variation of ± 3% or less in the coating direction and width direction excluding the edge of 10 mm.

  Finally, ITO was deposited by sputtering. With this manufacturing method, 1000 color filters were produced. The obtained color filter had no coating unevenness, the chromaticity was uniform over the entire surface of the substrate, and the quality was satisfactory.

  For example, in the manufacturing field of color filters for color liquid crystal displays, array substrates for TFTs, optical filters, printed boards, integrated circuits, semiconductors, etc. Can be used greatly when making adjustments to obtain a more accurate film thickness distribution. Further, it is used for manufacturing display members such as color filters and TFT array substrates that require such a highly accurate film thickness distribution.

1 is a schematic front sectional view schematically showing a die coater 1 according to an embodiment of the present invention. It is a time line figure which shows the relationship between the film thickness in one Example of this invention, a syringe pump coating liquid supply speed, and the board | substrate A movement speed. It is a time diagram which shows the relationship between the pressure in the application | coating start part in one Example of this invention, and piston machine operating speed. It is a diagram which shows the film thickness distribution with respect to the board | substrate position in one Example of this invention. FIG. 4 is a time diagram of pressure and piston machine operating speed in one embodiment of the present invention. FIG. 4 is a time diagram of pressure and piston machine operating speed in another embodiment of the present invention. FIG. 6 is a time diagram of pressure and piston machine operating speed in yet another embodiment of the present invention.

Explanation of symbols

1 Die coater 2 Base 4 Guide rail 6 Stage 10 Prop 20 Die (applicator)
22 Front lip 24 Rear lip 26 Manifold 28 Slit 32 Shim 34 Discharge port 36 Discharge port surface 40 Coating liquid supply device 42 Supply valve 44 Suction valve 46 Filter 47 Throttle valve 48 Pressure gauge 50 Syringe pump 52 Syringe 54 Piston 56 Main body 60 Supply hose 62 Suction hose 64 Tank 66 Coating liquid 68 Air pressure source 70 Vertical lift unit 72 Motor 74 Guide 78 Lift base 80 Suspension holding base 90 Wipe unit 92 Wipe head 94 Bracket 96 Slider 98 Drive unit 100 Tray 102 Car 120 Thickness sensor 122 Support base 130 Controller 132 Operation Panel A Substrate (Coating Member)
B Bead C Coating film

Claims (3)

An applicator having a discharge port extending in one direction is brought close to the member to be coated, a coating liquid having a viscosity of 1 to 50 mPaS is supplied from the constant capacity pump to the coating device, and the coating liquid is discharged from the applicator to the member to be coated. In the coating method of forming a coating film on the coated member by moving the coated member relative to the coating device, the coating member is applied in the path from the constant-capacity pump to the coating device under the same conditions as the coating in advance. The preliminary test for detecting pressure is repeated, and the operation speed for obtaining the target film thickness is reached so that the operation speed of the mechanical drive unit of the constant capacity pump becomes the desired shape so that the detected pressure waveform shape becomes a desired shape. when launching, each start-up any time interval shorter than the time of the pressure waveform, after defining the parameters by performing varied to reach the operation speed undershoot, by controlling the pressure A coating method characterized by the application of time. An applicator having a discharge port extending in one direction for discharging the coating liquid, a constant capacity pump for supplying the coating liquid with a viscosity of 1 to 50 mPaS to the applicator, a mounting table for holding a member to be coated, and the coating A coating device for forming a coating film on a member to be coated, comprising: a moving unit that relatively moves at least one of the container and the mounting table; and a proximity unit that brings the coating device close to the member to be coated, In addition, a pressure detector is provided in the path from the constant capacity pump to the applicator, and the pressure waveform detected by the pressure detector in the preliminary test under the same conditions as in the application is set to a desired shape. when launching to reach the operating speed for obtaining the thickness of the operating speed of the mechanical drive portion of the fixed displacement pump and the target, for each short arbitrary time intervals than the startup time of the pressure waveform, undershoots Defining the parameters by performing varied to reach the work rate, the actual coating apparatus characterized by comprising a pressure controller for controlling the pressure of the coating.   A display member is manufactured using the coating method according to claim 1, wherein the display member is manufactured.

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