JP2009166002A - Apparatus and method for applying solution - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for applying a solution which can discharge the solution from a nozzle formed in a head without being affected by bubbles contained in the solution. <P>SOLUTION: The apparatus for spraying/applying the solution on a substrate includes the head 7 having the nozzle for spraying the solution by an ink-jet method, a second solution tank 32 for storing the solution, solution supply tubes 21 and 34 which supply the solution to the second solution tank and supply the solution of the second solution tank to the head, and nano-bubble generators 51 which are installed in the solution supply tubes, give centrifugal force to the solution to be supplied, and smash the bubbles contained in the solution into nano-bubbles. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solution coating apparatus and a coating method in which a solution is ejected from a nozzle provided in a head by an inkjet method to be applied to a substrate.

  Generally, in a manufacturing process of a liquid crystal display device or a semiconductor device, there is a film forming process for forming a circuit pattern on a substrate such as a glass substrate or a semiconductor wafer. In this film forming process, a functional thin film such as an alignment film or a resist is formed on the plate surface of the substrate.

  In the case of forming a functional thin film on a substrate, an ink jet type coating apparatus that sprays a solution for forming the functional thin film from a nozzle and coats it on the plate surface of the substrate may be used.

  As shown in Patent Document 1, this coating apparatus has a transport table for transporting a substrate. Above the transport table, a plurality of heads with the nozzles formed in the transport direction of the substrate. In contrast, they are juxtaposed along a direction that is substantially orthogonal. Each head is supplied with a solution from a solution tank connected via a supply pipe. Thereby, the solution is ejected from the plurality of nozzles at a predetermined interval onto the upper surface of the substrate to be transported.

  When applying a solution to a substrate using an inkjet type coating device, if bubbles remain in the solution supply pipe or nozzle, the nozzle is clogged with bubbles and the solution is properly applied from the nozzle to the substrate. May not be injected.

  Therefore, before using the coating device, the inside of the solution tank is pressurized with gas, the solution is supplied to the supply pipe at a high pressure, and the nozzle is ejected vigorously from the nozzle. Thereby, the bubbles accumulated in the supply pipe and the nozzle are discharged together with the solution to fill the supply pipe and the head with the solution.

  On the other hand, in the solution stored in the solution tank, bubbles may be included in the solution due to, for example, air being involved when supplying the solution to the solution tank. If air bubbles are included in the solution, even if the air bubbles are removed from the supply pipe or nozzle, the bubbles are suitable for the solution from the nozzle to the substrate as if bubbles remained in the supply pipe or nozzle. May not be injected.

  In particular, since the diameter of the nozzle formed in the head used in the ink jet type coating apparatus is as fine as about several tens of μm, it is likely that bubbles are not generated in the nozzle, that is, the solution is not discharged. is there.

Therefore, when operating the coating apparatus, as described above, bubbles remaining in the supply pipe and the nozzle are removed, and at the same time, bubbles contained in the solution stored in the solution tank are removed.
JP 2004-223356 A

  By the way, in order to remove bubbles from a solution stored in a solution tank, bubbles contained in the solution are lifted by buoyancy and diffused to the atmosphere. Bubbles contained in the solution are usually several hundred to several millimeters in diameter, and have a buoyancy that floats in the solution. Therefore, the bubbles are removed by being diffused into the atmosphere using the buoyancy. It is possible.

  However, when removing bubbles in a solution using buoyancy, it takes a considerable amount of time to dissipate and remove bubbles contained in the solution in the atmosphere, which hinders improvement in productivity. In some cases, even if the solution is left for a long time, some of the bubbles remain in the solution. In such a case, the discharge of the solution from the nozzle may be adversely affected.

  The present invention relates to a solution coating apparatus and a coating method that can finely jet bubbles contained in a solution into nanobubbles so that the solution can be well jetted from the nozzle of the head without removing the bubbles from the solution. Is to provide.

The present invention is a coating apparatus for spray-coating a solution on a substrate,
A head having a nozzle for ejecting the solution by an inkjet method;
A solution tank for storing the solution;
A solution supply pipe for supplying a solution to the solution tank and supplying the solution in the solution tank to the head;
There is provided a solution coating apparatus, comprising: a bubble refining unit which is provided in the solution supply pipe and which makes bubbles contained in the solution supplied to the nozzle into nanobubbles.

The bubble refinement means
A liquid supply pump provided in the solution supply pipe;
A container having a shearing chamber that is provided in the solution supply pipe and swirls the solution supplied from the liquid supply pump to apply a centrifugal force, shears bubbles contained in the solution by the centrifugal force, and refines the bubbles into nanobubbles; It is preferable that it is comprised.

The solution supply pipe is provided with a plurality of solution tanks in series with respect to the flow direction of the solution,
It is preferable that the bubble refining means is provided so as to supply a solution in which the bubbles are refined into nanobubbles to a solution tank other than the solution tank located on the most downstream side in the solution flow direction closest to the head.

The present invention is a coating method in which a solution is sprayed from a nozzle and applied to a substrate,
Micronizing bubbles contained in the solution supplied to the nozzle into nanobubbles;
And a step of spraying and applying a solution containing fine bubbles to the substrate from the nozzle.

  According to the present invention, the bubbles contained in the solution are refined into nanobubbles without removing the bubbles, so that it is possible not only to prevent the bubbles from clogging the nozzle and the solution from being discharged but also the solution discharged from the nozzle. Since the bubbles contained in the substrate are fine, the solution can be uniformly applied to the substrate.

  An embodiment of the present invention will be described below with reference to the drawings.

  The solution coating apparatus according to the present invention shown in FIGS. A pair of rails 2 spaced apart from each other at a predetermined interval are laid along the longitudinal direction of the base 1 on the upper surface of the base 1. A table 3 is provided on the rail 2 so as to be able to travel, and is driven to travel by a drive source (not shown). A large number of support pins 4 are provided on the upper surface of the table 3, and a glass substrate W used for, for example, a liquid crystal display device is supplied and supported on these support pins 4.

  Above the substrate W driven together with the table 3, a plurality of heads for spraying and applying a solution for forming a functional thin film on the substrate W by an ink jet method, in this embodiment, three heads 7 are provided on the substrate W. Are arranged in a row along a direction intersecting the traveling direction.

  Each head 7 includes a head body 8 as shown in FIG. The head body 8 is formed in a cylindrical shape, and its lower surface opening is closed by a flexible plate 9. The flexible plate 9 is covered with a nozzle plate 11, and a plurality of liquid chambers 12 are formed between the nozzle plate 11 and the flexible plate 9.

  Each liquid chamber 12 communicates with a main pipe line 11A formed in the nozzle plate 11 via a branch pipe (not shown), and a solution is transferred from the main pipe line 11A via the branch pipe line to each liquid chamber 12. To be supplied. One end of the main pipeline 11A is connected to a liquid supply hole 13 described later, and the other end is connected to a recovery hole 17 described later.

  The liquid supply hole 13 that communicates with the liquid chamber 12 is formed at one longitudinal end of the head body 8. A solution for forming a functional thin film such as an alignment film or a resist is supplied from the liquid supply hole 13 to the liquid chamber 12. Thereby, the inside of the liquid chamber 12 is filled with the solution.

  As shown in FIG. 4, a plurality of, in this embodiment, 37 nozzles 14 are formed in a staggered pattern in the nozzle plate 11 along a direction orthogonal to the transport direction of the substrate W. As shown in FIG. 3, a plurality of piezoelectric elements 15 facing the nozzles 14 are provided on the upper surface of the flexible plate 9.

Each piezoelectric element 15 is supplied with a drive voltage by a drive circuit unit 16 provided in the head body 8 as will be described later. As a result, the piezoelectric element 15 expands and contracts and partially deforms the flexible plate 9, so that the solution is sprayed and applied to the upper surface of the substrate W to which the solution is conveyed from the nozzle 14 facing the piezoelectric element 15.
In addition, if the operation amount of the piezoelectric element 15 is controlled by changing the strength of the voltage applied to the piezoelectric element 15 or the pulse width, the discharge amount of the solution from the nozzle 14 facing each piezoelectric element 15 can be changed.

As shown in FIG. 3, the recovery hole 17 communicating with the liquid chamber 12 is formed at the other longitudinal end of the head body 8. The solution supplied from the liquid supply hole 13 to the liquid chamber 12 can be recovered from the recovery hole 17. That is, each head 7 can recover not only the solution supplied to the liquid chamber 12 from the nozzle 14 but also the recovery hole 17 through the liquid chamber 12.
A supply branch pipe 22 branched from the first solution supply pipe 21 is connected to the liquid supply hole 13 of each cloth head 7, and a recovery branch pipe 24 branched from the solution recovery pipe 23 is connected to the recovery hole 17. It is connected.

  As shown in FIG. 1, a first solution supply pipe 21 is connected to the liquid supply hole 13 of each head 7, and a supply branch pipe 22 branched from a solution recovery pipe 23 is branched to the recovery hole 17. A branch pipe 24 is connected. The supply branch pipe 22 is provided with a supply on / off valve 25, and the recovery branch pipe 24 is provided with a recovery on / off valve 26. The tips of the first solution supply pipe 21 and the solution recovery pipe 23 are connected via a communication valve 27. Further, the recovery pipe 23 is provided with a main recovery valve 28 at a portion closer to the base end than the recovery branch pipe 24.

  The base end of the first solution supply pipe 21 is connected to the bottom of the first solution tank 31 in which the solution L is stored. The proximal end of the recovery tube 23 is connected to a second solution tank 32 that stores the solution L to be supplied to the first solution tank 31.

  A second solution supply pipe 34 having a supply valve 33 is branched from the base end portion of the recovery pipe 23, and the second solution supply pipe 34 is connected to the bottom of the first solution tank 31. That is, the second solution supply pipe 34 is connected to the second solution tank 32 through a part of the solution recovery pipe 23.

  An air release pipe 35 is connected to the upper part of the first solution tank 31. The atmosphere opening pipe 35 is provided with a first opening / closing control valve 36. When the first opening / closing control valve 36 is opened, the inside of the first solution tank 31 is communicated with the atmosphere.

  Note that the atmosphere release pipe 35 communicates with the atmosphere through a processing device (not shown) for treating the vaporized solvent contained in the gas diffused into the atmosphere from the atmosphere release pipe 35 as described later. Therefore, the gas flowing through the atmosphere release pipe 35 receives resistance.

  A gas supply pipe 38 provided with a second opening / closing control valve 37 is connected to the upper part of the first solution tank 31. The gas supply pipe 38 is supplied with an inert gas such as nitrogen from a gas supply source (not shown).

  A filter 39 and a third opening / closing control valve 40 are sequentially connected to the gas supply pipe 38 upstream of the second opening / closing control valve 37. The third open / close control valve 40 is provided with a flow restrictor 41 in parallel. This flow restrictor 41 and the third on-off control valve 40 constitute gas flow control means.

  Similar to the first solution tank 31, an atmosphere release pipe 44 having a fourth open / close control valve 43 is connected to the upper part of the second solution tank 32. Further, the second solution tank 32 is connected to the third solution tank 47 by a third solution supply pipe 46 provided with a filter 45 in the middle.

  Although not shown, a gas supply pipe for supplying an inert gas such as nitrogen from a gas supply source (not shown) is connected to the second solution tank 32 as well as the first solution tank 31. Yes.

  The third solution tank 47 contains a solution L supplied from a solution supply source (not shown). The solution L is supplied by the liquid supply pump 48 provided in the third solution supply pipe 46. The second solution tank 32 is supplied.

  Further, the third solution supply pipe 46 is provided with a fourth open / close control valve 49 on the downstream side of the filter 45 so that the supply and supply stop of the solution L can be switched. Further, the third solution supply pipe 46 extends to a position where the tip thereof is close to the bottom of the second solution tank 32. Therefore, when the solution L is in the second solution tank 32, the tip of the third solution supply pipe 46 is immersed in the solution L, so that the solution L supplied from the third solution supply pipe 46 is the second solution L. Since it directly enters the solution L stored in the solution tank 32, no gas is involved.

Further, even when there is no solution L in the second solution tank 32, the solution L is suppressed from jumping when the solution L is supplied from the third solution supply pipe 46 to the second solution tank 32. It is possible to prevent gas from being entrained in L.
In this embodiment, the first solution supply pipe 21, the second common supply pipe 34, and the third solution supply pipe 46 constitute a solution supply pipe.

  On the discharge side of the liquid supply pump 48, a nanobubble generator 51 is provided as a bubble refining means. The nanobubble generator 51 includes a hollow container 53 having a shear chamber 52 therein as shown in FIGS. A supply port body 54 that supplies the solution L discharged from the supply pump 48 to the shear chamber 52 through the third solution supply pipe 46 is provided at one axial end portion of the outer peripheral surface of the container 53. .

  The supply port body 54 is inclined at an angle α toward the one axial end of the container 53 as shown in FIG. 5, and is inclined at an angle β with respect to the radial direction as shown in FIG. Thus, the solution discharged from the liquid supply pump 48 at a predetermined pressure and supplied from the supply port body 54 to the shear chamber 52 is swung along the inner peripheral surface of the shear chamber 52 while the container 53 It progresses from one axial direction to the other end.

  When the solution L advances in the axial direction while turning the shear chamber 52 in the direction indicated by the arrow, bubbles contained in the solution L are divided and refined by the shearing force generated by the turning. In this embodiment, the pressure and angle at which the solution L is discharged into the shear chamber 52 are set so that the bubbles contained in the solution L are refined into nanobubbles having a diameter of 1 μm or less.

  The solution L in which the bubbles are refined into nanobubbles flows out from the outlet body 55 connected to the radial center of the other axial end surface of the container 53, and the second solution is supplied through the third solution supply pipe 46. It is supplied to the solution tank 32.

  The shear chamber 52 is formed in a conical shape whose sectional shape gradually decreases from one end where the supply port body 54 is connected to the other end where the outlet body 55 is connected. As a result, the solution L supplied from the supply port body 54 to the shear chamber 52 by the liquid supply pump 48 at a predetermined pressure gradually decreases in cross-sectional area of the shear chamber 52 toward the outlet body 55. The shear chamber 52 is swirled with almost no decrease in swirling speed. As a result, since the shearing force having almost the same strength acts on the bubbles contained in the solution L until the solution L flows out from the outlet body 55, the bubbles contained in the solution L are surely miniaturized. become.

  Depending on the pressure of the solution L supplied to the shear chamber 52 and the setting of the conical inclination angle of the shear chamber 52, it is possible to increase the swirl speed of the solution L and cause it to flow out from the outlet body 55. .

  The solution L containing nanobubbles supplied to the second solution tank 32 has a low surface tension and high permeability. The diameter of nanobubbles contained in the solution L is about 1 μm, which is sufficiently smaller than the diameter of the nozzle 14 provided in the head 7, which is several tens of μm.

  Therefore, the solution L containing nanobubbles is smoothly discharged onto the substrate W without clogging the nozzles 14 of the head 7 due to the pressure generated by the expansion and contraction of the piezoelectric element 15. Then, the solution L containing nanobubbles is surely and uniformly applied to the plate surface of the substrate W by a small surface tension and high permeability.

  The supply on / off valve 25, the recovery on / off valve 26, the main recovery valve 28, the supply valve 33, and the first to fourth on / off control valves 36, 37, 40, and 43 are controlled to open and close by a control device (not shown). The feed pump 48 is controlled to be started and stopped by the control device.

  Further, the level of the solution L in the first solution tank 31 is detected by the level sensor 60. When the level sensor 60 detects that the liquid level of the solution L in the first solution tank 31 is below a predetermined level, an inert gas is supplied from a gas supply pipe (not shown) based on the detection. The solution L in the second solution tank 32 passes through the pressure and is supplied to the first solution tank 31.

  That is, the solution L is stored in the third solution tank 47, the bubbles contained in the solution L are refined into nanobubbles, the solution L is supplied to the second solution tank 32, and then the closest to the head 7. The first solution tank 31 was supplied. Therefore, the supply pressure of the solution L by the inert gas supplied from a gas supply pipe (not shown) is set to be smaller than the supply pressure of the solution L by the supply pump 48, and the solution L is supplied from the second solution tank 32 to the first. Since it can supply to the solution tank 31, the pressure fluctuation of the solution L in the 1st solution tank 31 can be made small. Accordingly, the solution L can be supplied from the first solution tank 31 to the nozzles 14 of the heads 7 at a stable pressure.

  As shown in FIG. 2, one end surface of the table 3 is provided with an attachment member 61 having an L-shaped side surface with a vertical side fixed to the end surface of the table 3. An upper and lower cylinder 62 is provided on the other horizontal side of the mounting member 61 with the axis line vertical.

  A mounting plate 64 is attached to the rod of the upper and lower cylinders 62 via an elastic member 63. Three holding members 65 made of an elastic material such as blade-like rubber having a length corresponding to each head 7 are held on the upper surface of the mounting plate 64 by the holding members 66 so as to be displaced in the vertical direction. Each presser member 65 is elastically biased in the upward direction by a spring 67 provided on the holding member 66.

  The placement plate 64 is provided with a wiping member 68 formed of an elastic material such as a blade-like rubber in parallel with the pressing member 65. The wiping member 68 is formed taller than the pressing member 65.

  The mounting plate 64 described above is provided at the inner bottom of the collection tank 71. A guide plate 72 is provided on one side of the collection tank 71, and a guide member 73 is provided on the guide plate 72. The guide member 73 is guided by a guide rail 74 provided on the end surface of the table 3 along the vertical direction and can move up and down.

  Accordingly, when the upper and lower cylinders 62 are driven, the mounting plate 64 is driven and the guide plate 72 is moved up and down along the guide rail 74, so that the mounting plate 64 is swung in the front-rear and left-right directions. Is regulated and moves up and down.

  A collection tank 75 shown in FIG. 1 is connected to the collection tank 71. The recovery tank 75 recovers the solution sprayed from the nozzle 14 to the recovery tank 71 when the bubbles of the nozzle 14 of the head 7 are removed.

  When the mounting plate 64 is raised and the nozzle 14 of each head 7 is closed by the pressing member 65, the solution L in the first solution tank 31 is transferred from the liquid supply hole 13 of each head 7 to the liquid chamber 12 and the recovery hole. 17 can be circulated. Thereby, the first solution supply pipe 21, the head 7, and the recovery pipe 23 can be degassed.

  If the solution L is supplied to each head 7 in a state in which the nozzle 14 is opened and the solution L in the first solution tank 31 does not return to the recovery pipe 23, the solution L is ejected from the nozzle 14, so Can be removed.

  When the solution L is applied to the substrate W, if the wiping member 68 is set to a height at which the wiping member 68 comes into contact with the nozzle surface where the nozzles 14 of the head 7 are opened, the nozzles are moved when the substrate W reciprocates below the head 7. The solution L remaining on the surface can be wiped off.

Next, a case where the solution L is applied to the substrate W by the coating apparatus having the above configuration will be described.
The liquid level of the solution L in the first solution tank 31 is maintained at a level lower than the nozzle surface of the head 7 by a predetermined dimension, and the level, that is, the water head h between the nozzle surface and the liquid surface shown in FIG. It is controlled by the level sensor 60.

  When the solution L is not applied to the substrate W, a small amount of inert gas is supplied into the first solution tank 31 through the flow restrictor 41 and the second open / close control valve 37, and the first open / close control valve 36. The air is released from the open air pipe 35 through the air.

  As a result, the solution L in the first solution tank 31 is prevented from coming into contact with the atmosphere, so that the solution L is prevented from deteriorating due to reaction with oxygen and moisture in the atmosphere. Since the flow rate of the inert gas supplied to the first solution tank 31 is set to a very small amount by the flow restrictor 41, the evaporation amount of the solvent contained in the solution L in the first solution tank 31 is suppressed. Thereby, it is possible to suppress the concentration of the solution L in the first solution tank 31 from changing with time.

  If the substrate W has been transported below the head 7 by the table 3, the piezoelectric element 15 is energized by the drive circuit unit 16 and the solution L supplied to the liquid chamber 12 of the head 7 is ejected from the nozzle 14 onto the substrate W. To do. Thereby, the solution can be spray-coated on the substrate W.

  Further, since the liquid level of the solution L in the first solution tank 31 is controlled by the level sensor 60 so as to be constant, it is possible to prevent the water head h between the liquid level and the nozzle surface of the head 7 from fluctuating. The

  That is, the solution L is ejected from the nozzle 14 by the operation of the piezoelectric element 15 under a preset water head h. Therefore, since a predetermined amount of the solution L can be precisely ejected from each nozzle 14, the solution L can be applied to the substrate W in a uniform amount.

  In the solution L supplied to the substrate W, bubbles contained in the solution L are refined into nanobubbles by the nanobubble generator 51. If the bubbles are miniaturized into nanobubbles, the size of the bubbles is much smaller than that of the nozzle 14 system. Therefore, when the solution L is discharged from the nozzle 14 of the head 7, the bubbles are clogged in the nozzle 14. The solution L is not reliably discharged from the nozzle 14.

  In addition, the solution L containing fine bubbles in nanobubbles has low surface tension, high permeability, and improved wettability. Therefore, the solution L discharged from the nozzle 14 to the substrate W is surely adhered to a desired portion of the plate surface of the substrate W, so that the application of the solution L to the substrate W can be performed uniformly and reliably. Can be done.

  Further, since the solution L containing nanobubbles easily spreads on the substrate due to the improved wettability, the uniformity of the film thickness of the alignment film formed by integrating the solutions L attached on the substrate W is improved. Therefore, the quality of the functional film to be formed can be improved.

  The shear chamber 52 of the nanobubble generator 51 is formed in a conical shape in which the cross-sectional area gradually decreases toward the outlet body 55 from which the solution L flows out from the supply port body 54 to which the solution L is supplied. Therefore, the swirling speed of the solution L swirling through the shear chamber 52 is hardly decelerated while flowing toward the outlet body 55, so that the bubbles contained in the solution L can be refined efficiently and reliably. It becomes possible.

  The solution L in the third solution tank 47 is forcibly supplied to the nanobubble generator 51 by the supply pump 48 to refine the bubbles contained in the solution L, and the solution L is supplied to the head 7 and discharged from the nozzle 14. I tried to make it.

  Therefore, the solution L can be quickly supplied to the head 7 as compared with the conventional case where the solution L containing bubbles is left and the bubbles are removed from the solution L, so that productivity can be improved. It has the advantage of being able to.

  A plurality of, in this embodiment, first to third three solution tanks 31, 32, 47 are provided in the pipe for supplying the solution L to the head 7, and the solution L is supplied to the third solution tank by the liquid supply pump 48. When being supplied from 47 to the second solution tank 32, the bubbles contained in the solution L are refined into nanobubbles by the nanobubble generator 51 provided in the third solution supply pipe 46.

  Therefore, the pressure of the solution L in the first solution tank 31 supplied from the second solution tank 32 hardly fluctuates, and the liquid surface of the first solution tank 31 and the nozzle surface of the head 7 are not changed. Therefore, the solution L can be discharged from the nozzle 14 in a precise amount with the pressure generated by the expansion and contraction of the piezoelectric element 15.

  In the one embodiment, the three solution tanks are provided in series in the solution supply pipe. However, only two of the first solution tank and the second solution tank may be provided. A liquid supply pump and a nanobubble generator may be provided in the second solution supply pipe connecting the one solution tank and the second solution tank.

  Further, the solution returned from the recovery hole of each head through the solution recovery tube is returned to the second solution tank, but may be returned to the third solution tank.

The schematic block diagram which shows the coating device of one Embodiment of this invention. The side view which shows the table provided in the base. The longitudinal cross-sectional view of a head. The figure which shows the lower surface which the nozzle of the head opened. The figure which cut | disconnected the container of the nano bubble generator along the axial direction. The figure which cut | disconnected the said container along the radial direction at the one end part of the axial direction.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 7 ... Head, 14 ... Nozzle, 21 ... 1st solution supply pipe, 31 ... 1st solution tank, 32 ... 2nd solution tank, 34 ... 2nd solution supply pipe, 46 ... 3rd solution supply pipe , 47 ... third solution tank, 48 ... liquid feed pump, 51 ... nanobubble generator (bubble refinement means), 53 ... container, 52 ... shear chamber.

Claims (5)

A coating apparatus for spraying and applying a solution to a substrate,
A head having a nozzle for ejecting the solution by an inkjet method;
A solution tank for storing the solution;
A solution supply pipe for supplying a solution to the solution tank and supplying the solution in the solution tank to the head;
A solution coating apparatus, comprising: a bubble refining unit which is provided in the solution supply pipe and which makes bubbles contained in the solution supplied to the nozzle into nanobubbles. The bubble refinement means
A liquid supply pump provided in the solution supply pipe;
A container having a shearing chamber that is provided in the solution supply pipe and swirls the solution supplied from the liquid supply pump to apply a centrifugal force, shears bubbles contained in the solution by the centrifugal force, and refines the bubbles into nanobubbles; The solution coating apparatus according to claim 1, comprising:   3. The solution coating apparatus according to claim 2, wherein the shear chamber is formed in a conical shape in which a cross-sectional area gradually decreases from the solution supply side to the outflow side. The solution supply pipe is provided with a plurality of solution tanks in series with respect to the flow direction of the solution,
The bubble miniaturization means is provided so as to supply a solution in which bubbles have been refined into nanobubbles to a solution tank other than the solution tank located on the most downstream side in the flow direction of the solution closest to the head. The solution coating apparatus according to claim 1. An application method in which a solution is sprayed from a nozzle and applied to a substrate,
Micronizing bubbles contained in the solution supplied to the nozzle into nanobubbles;
And a step of spray-coating a solution containing micronized bubbles from the nozzle onto the substrate.

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