JP2005103453A - Solution application apparatus and degassing method for application apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an application apparatus capable of reliably and efficiently removing gas in a head having a nozzle. <P>SOLUTION: The application apparatus comprises a head 7 having a nozzle 14 for jetting a solution by ink-jet method, a supply pipe 21 connecting a storage tank 32 and the head 7, the supply tank 31 installed in the supply pipe for setting the height of the solution surface, a gas supply pipe 46 for pressurizing the solution in the storage tank and supplying the solution to the head via the supply tank at the time of degassing in the head, an aspirator 33 installed in the portion between the storage tank of the supply pipe and the supply tank, and a recovery pipe 23 connecting the head and a suction port of the aspirator so as to pass the solution, which is supplied to the head but is not jetted by the nozzle, therein by the suction by the aspirator. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a coating apparatus for spraying a solution onto a substrate by an ink jet method and a degassing method for the coating apparatus.

  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 may be used in which a solution for forming the functional thin film is sprayed from a nozzle and applied to the plate surface of the substrate.

  This coating apparatus has a transport table for transporting a substrate, and above the transport table, a plurality of heads in which the nozzles are formed are along a direction substantially perpendicular to the transport direction of the substrate. For example, they are arranged in a staggered pattern. Thereby, the solution is spray-applied on the upper surface of the substrate to be transported at a predetermined interval in a direction intersecting the transport direction from a plurality of nozzles.

  When a solution is applied to a substrate using an ink jet type coating apparatus, if bubbles remain in a head or a pipe for supplying the solution, bubbles are included in droplets ejected from the nozzle. As a result, ejection failure may occur, and thus the solution may not be uniformly applied to the substrate.

  Therefore, before using the coating apparatus, the solution is pressurized and supplied to the head, and bubbles remaining in the head are discharged together with the solution, thereby degassing the head.

  The coating device has a storage tank in which a clean solution is stored. A supply tank is connected to the storage tank by piping. When a solution is ejected from a nozzle by an ink jet method, a certain amount of solution is ejected onto a substrate by expansion and contraction of a piezoelectric element provided facing the nozzle. The liquid level is almost equal to or slightly lower than the tip surface of the nozzle.

  The supply tank is provided for setting the height of the liquid level of the solution. By setting the liquid level of the solution to a predetermined height, it is possible to prevent the amount of solution ejected from the nozzle from fluctuating due to a water head difference between the tip surface of the nozzle and the liquid level of the solution stored in the supply tank. I am doing so.

  Conventionally, when degassing the inside of the head, a clean solution stored in a storage tank is supplied to a supply tank by a first pressurizing means. When a predetermined amount of solution is stored in the supply tank, pressurization of the storage tank by the first pressurizing means is stopped, and the solution stored in the supply tank is pressurized by the second pressurizing means to the head. Supply.

  Most of the solution supplied to the head, that is, the solution other than the solution flowing out from the nozzle, flows in the head, flows out into the recovery pipe together with the bubbles in the head, and is recovered in the storage tank through the recovery pipe. ing. That is, since the inside of the supply tank is pressurized when the head is deaerated, the solution flowing through the head cannot be returned to the supply tank, but is returned to the storage tank.

  In order to degas the head as described above, the solution stored in the storage tank must be stored in the supply tank. For this reason, it takes time to store the solution in the supply tank, and deaeration cannot be performed efficiently.

  In addition, in order to perform deaeration, a pressurizing means for pressurizing the solution in the supply tank is required exclusively for degassing. In some cases, the cost increases. Furthermore, if the number of heads is large, all the heads need to have enough solution to deaerate at the same time, so the supply tank must be sized to store that much, The size of the apparatus will be increased.

  On the other hand, since the pipe for supplying the solution to the head is bent, it is inevitable that the pressure of the solution flowing through the pipe fluctuates. When the pressure of the solution fluctuates, bubbles are generated thereby, so that bubbles are included in the solution supplied to the head.

  Therefore, a deaeration means for separating and removing the gas contained in the solution is provided on the upstream side of the head so that a solution containing no bubbles is supplied to the head. When a deaeration unit is provided on the upstream side of the head, an exhaust pipe is connected to the deaeration unit, and the gas separated by the deaeration unit is discharged through the exhaust pipe.

  However, when an exhaust pipe is connected to the deaeration means, when a solution is pressurized and supplied to the head when the head is deaerated, the solution is supplied to the exhaust pipe having a smaller flow resistance than the head. Since it becomes difficult to flow to the head side, the head may not be surely degassed.

  According to the present invention, the time required for deaeration in the head can be shortened by allowing the solution to continuously flow from the storage tank to the head through the supply tank to perform the deaeration of the head. An object of the present invention is to provide a coating apparatus and a deaeration method.

  In the present invention, even if a deaeration means for removing bubbles contained in the solution supplied to the head is provided on the upstream side of the head, the solution supplied from the supply tank when the head is deaerated An object of the present invention is to provide a coating apparatus and a coating method capable of reliably flowing to a head.

The present invention provides a solution coating apparatus for spray-coating a solution on a substrate.
A head having a nozzle for ejecting the solution by an inkjet method;
A storage tank storing the solution;
A supply pipe connecting the storage tank and the head;
A supply tank that is provided in the middle of the supply pipe and sets the height of the liquid level of the solution when spraying the solution onto the substrate;
Pressurizing means for pressurizing the solution stored in the storage tank when degassing the head and supplying the solution to the head through the supply tank;
An aspirator having an inflow port, an outflow port, and a suction port, and provided in the portion of the supply pipe between the storage tank and the supply tank via the inflow port and the outflow port;
A recovery pipe connected to the head and the suction port of the aspirator and supplied to the head and flowing through the head without being ejected from the nozzle; In the solution applicator.

  It is preferable that a bubble separating means for separating bubbles contained in the solution flowing through the aspirator and flowing into the supply tank is provided in the supply tank.

In the present invention, when a head having a nozzle for spraying a solution applied to a substrate by an ink jet method is depressurized, a solution stored in a storage tank is pressurized, and the solution is sprayed and applied to the substrate on the substrate. In the deaeration method performed by flowing to the head through a supply tank for setting the liquid level of
Pressurizing the solution stored in the storage tank and supplying it to the head through the supply tank;
Allowing the bubbles in the head to flow out together with the solution by flowing the solution through the head;
And a step of sucking the solution containing bubbles flowing out of the head by the flow of the solution supplied under pressure to the head and returning it to the supply tank.

The present invention provides a solution coating apparatus for spray-coating a solution on a substrate.
A head having a nozzle for ejecting the solution by an inkjet method;
A storage tank storing the solution;
A supply pipe connecting the storage tank and the head;
A supply tank that is provided in the middle of the supply pipe and sets the height of the liquid level of the solution when spraying the solution onto the substrate;
Pressurizing means for pressurizing the solution stored in the storage tank when degassing the head and supplying the solution to the head through the supply tank;
A deaeration means provided between the supply tank and the head for removing bubbles contained in the solution flowing from the supply tank to the head;
A recovery pipe that is pressurized by the pressurizing means and flows from the degassing means through the head and from which the degassed solution flows out;
The degassing means and the recovery pipe are connected to discharge air bubbles degassed by the degassing means to the recovery pipe, and the solution pressurized by the pressurization means is passed to the head through the degassing means. And an exhaust pipe having an inner diameter dimension so that only a part of the solution flows into the recovery pipe and most of the remaining solution flows into the head when degassing the head. It is in a solution coating apparatus.

The present invention relates to a degassing method for degassing a head having a nozzle that ejects a solution applied to a substrate by an ink jet method.
Degassing the pressurized solution with degassing means and supplying it to the head;
A step of degassing the inside of the head by flowing the solution supplied to the head through the head and outflowing into the collection tube;
Flowing the gas degassed by the degassing means through the exhaust pipe to the recovery pipe;
Applying only a part of the solution pressurized and supplied to the deaeration means to the exhaust pipe, and flowing most of the remaining solution to the head through the deaeration means. It is in the deaeration method of the device.

  According to the present invention, since the solution stored in the storage tank can be pressurized and supplied to the head through the supply tank and returned from the head to the supply tank, the solution in the storage tank can be used when degassing the head. Can be done without changing to the supply tank.

  According to the present invention, when the pressurized solution is supplied to the head through the degassing means and the head is degassed, the solution flows into the exhaust pipe that discharges the bubbles connected to the degassing means. Since the solution is allowed to flow through the head, the head can be surely degassed.

  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 as dropping portions for spraying and applying a solution for forming a functional thin film such as a polyimide film on the substrate W by an ink jet method, In the embodiment, the three heads 7 are arranged in a line along the direction intersecting the traveling direction of the substrate W.

  The 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 liquid chamber 12 is formed between the nozzle plate 11 and the flexible plate 9.

  A liquid supply hole 13 communicating with the liquid chamber 12 is formed at one longitudinal end of the head body 8. From the liquid supply hole 13, a solution as a liquid for forming a functional thin film such as an alignment film or a resist is supplied 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 nozzles 14 are formed in the nozzle plate 11 in a zigzag pattern along a direction orthogonal to the transport direction of the substrate W. A plurality of piezoelectric elements 15 are provided on the upper surface of the flexible plate 9 so as to face the nozzles 14 as shown in FIG.

  A driving voltage is supplied to each piezoelectric element 15 by a driving unit 16 provided in the head body 8. As a result, the piezoelectric element 15 expands and contracts, and the flexible plate 9 is partially deformed, so that the solution is sprayed and applied to the upper surface of the substrate W from the nozzle 14 facing the piezoelectric element 15.

  As shown in FIG. 3, a 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, the head 7 can not only eject the solution supplied to the liquid chamber 12 from the nozzle 14 but also collect the solution from the recovery hole 17 through the liquid chamber 12.

  As shown in FIGS. 1 and 3, a supply branch pipe 22 branched from a solution supply pipe 21 is connected to the liquid supply hole 13 of each head 7, and a recovery branch branched from a recovery pipe 23 is connected to the recovery hole 17. A branch pipe 24 is connected. The supply branch pipe 22 is sequentially provided with a supply opening / closing valve 25 and a deaeration device 71 having a configuration described later, and the recovery branch pipe 24 is provided with a recovery opening / closing valve 26. The tips of the supply pipe 21 and the 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 supply pipe 21 is connected to the bottom of a supply tank 31 having a configuration described later as a liquid storage device in which the solution L is stored. One end of a supply branch pipe 34 provided with an aspirator 33 is connected to the upper part of the supply tank 31. The other end of the supply branch pipe 34 is connected to a storage tank 32 that stores the solution L supplied to the supply tank 31.

  An air release pipe 35 is connected to the upper part of the supply 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 supply tank 31 communicates 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.

  The aspirator 33 has an inflow port 33a, an outflow port 33b, and a suction port 33c, and is provided by connecting the inflow port 33a and the outflow port 33b to the supply branch pipe 34. A base end of the recovery pipe 23 is connected to the suction port 33c. When the solution flows into the supply branch pipe 34 and flows out from the outlet 33b through the inlet 33a of the aspirator 33, the suction port 33c becomes negative pressure. With the negative pressure, the solution flows through the collection tube 23 connected to the suction port 33c.

  An atmosphere release pipe 44 having a second opening / closing control valve 43 is connected to the upper portion of the storage tank 32, similarly to the supply tank 31. Further, a gas supply pipe 46 having a third opening / closing control valve 45 is connected. A filter 47 and a fourth open / close control valve 48 are sequentially connected to the gas supply pipe 46. The fourth open / close control valve 48 is provided with a flow restrictor 49 in parallel.

  The supply on / off valve 25, the recovery on / off valve 26, the main recovery valve 28, and the first to fourth on / off control valves 36, 43, 45, and 48 are controlled to open / close by a control device (not shown). . Furthermore, the level of the solution L in the supply tank 31 is detected by the level sensor 50. When the level sensor 50 detects that the liquid level of the solution L has become below a predetermined level, the solution L is replenished from the storage tank 32 based on the detection. That is, the solution L in the storage tank 32 is pressurized by the inert gas supplied through the third opening / closing control valve 45, so that the solution L is supplied to the supply tank 31.

  As shown in FIG. 2, one end surface of the table 3 is provided with an attachment member 51 having an L-shaped side surface with a vertical side fixed to the end surface of the table 3. On the other horizontal side of the mounting member 51, an upper and lower cylinder 52 is provided with the axis line vertical.

  A mounting plate 54 is attached to the rod of the upper and lower cylinders 52 via an elastic member 53. Three wiping members 58 made of an elastic material such as blade-like rubber having a length corresponding to each head 7 are provided on the upper surface of the mounting plate 54.

  The placement plate 54 is provided on the inner bottom of the collection tank 61. A guide plate 62 is provided on one side of the collection tank 61, and a guide member 63 is provided on the guide plate 62. The guide member 63 is guided by a guide rail 64 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 52 are driven, the mounting plate 54 is driven and the guide plate 62 moves up and down along the guide rails 64, so that the mounting plate 54 swings in the front-rear and left-right directions. Is regulated and moves up and down.

  A collection tank 65 shown in FIG. 1 is connected to the collection tank 61. The recovery tank 65 recovers the solution sprayed from the nozzle 14 to the recovery tank 61 when the bubbles of the head 7 and the nozzle 14 are removed.

  When the solution L is applied to the substrate W, if the wiping member 58 is set to a height at which the wiping member 58 comes into contact with the nozzle surface where the nozzle 14 of the head 7 is opened, the nozzle is moved when the substrate W reciprocates below the head 7. The solution L remaining on the surface can be wiped off.

  The deaeration device 71 is interposed in a portion of the supply branch pipe 22 branched from the supply pipe 21 between the supply on / off valve 25 and the head body 8 (this portion is an interposed portion). ing. That is, this deaeration device 71 has a cylindrical container 72 as shown in FIG. A first connection portion 71 a as a supply portion is formed on the upper portion of the peripheral wall of the container 72. The upstream part 22a of the interposition part of the supply branch pipe 22 is connected to the first connection part 71a. Thereby, the solution L from the supply tank 31 is supplied into the container 72.

  A second connection part 71b as an outflow part to which the downstream part 22b of the interposed part of the supply branch pipe 22 is connected is formed at the bottom of the container 72. Thereby, the solution L supplied into the container 72 is supplied to the liquid supply hole 13 of the head body 8 from the bottom.

  A gas separation member 73 is provided on the inner bottom of the container 72. This gas separation member 73 is formed in a mesh shape with a material that easily adheres to bubbles, that is, a material having a contact angle with the solution L of greater than 10 °, for example, a polyimide resin. Has been. Thereby, when the solution L supplied into the container 72 flows out from the downstream portion 22b of the intervening portion of the supply branch pipe 22 connected to the bottom through the mesh of the gas-liquid separation member 73, to the head body 8. Bubbles contained in the solution adhere to the gas-liquid separation member 73 and remain in the container 72.

  The small bubbles b adhering and remaining on the gas-liquid separation member 73 gather together and grow into large bubbles B, and rise inside the container 72 when the buoyancy increases. A third connection portion 71c as an exhaust portion is formed on the upper portion of the container 72, to which one end of an exhaust pipe 74 serving as an exhaust portion of the present invention is connected. The other end of the exhaust pipe 74 is connected to the recovery pipe 23 via the recovery branch pipe 24. Thereby, the bubbles B floating in the container 72 flow into the storage tank 32 from the exhaust pipe 74 through the recovery pipe 23, and are diffused into the atmosphere from the atmosphere open pipe 44 connected to the storage tank 32.

The diameter of the container 72 is D, the flow rate of the solution L supplied into the container 72 is Q, the diameter of bubbles rising in the container 72 is a, the viscosity of the solution L is ζ, the bubble density is ρ ₁ , and the solution density is If ρ ₂ and the gravitational acceleration is g,
D> [(4Q / π) × {6πaζ / (4πa ³ ρ ₁ g / 3)
− (4πa ³ ρ ₂ g / 3)} ^1/2 ... Solution that causes bubbles B grown in the container 72 to flow into the container 72 by setting D so as to satisfy the relationship of the expression (1) It is possible to ascend against the speed of L.

  In addition, the container 72 is formed of a material that does not easily adhere to bubbles, that is, a material having a contact angle with the solution L of less than 10 °, for example, glass or the like when the solution L is polyimide. Alternatively, it may be formed of a material that is relatively difficult to attach bubbles, such as ceramic or ceramic. The gas separation member 74 is entirely formed in a mesh shape with a synthetic resin, but it may be formed by coating a synthetic mesh on a metal mesh such as stainless steel. In short, bubbles are likely to adhere to at least the surface. What is necessary is just to form with a synthetic resin.

  When the solution L in the storage tank 32 is pressurized by the inert gas supplied through the third opening / closing control valve 45, the solution L is supplied to the supply tank 31. When the supply of the solution to the supply tank 31 is continued and the pressure in the supply tank 31 rises, the solution flows out of the supply tank 31 and into the container 72 of the deaeration device 71 upstream of the supply branch pipe 22. Flows in through 22a.

  Connected to the container 72 are a downstream portion 22b of the supply branch pipe 22 communicating with the liquid supply hole 13 of the head 7 and an exhaust pipe through which bubbles B from which bubbles removed from the solution flow out. For this reason, the solution flowing into the container 72 from the upstream portion 22a may not flow to the head 7 through the downstream portion 22b but may flow to the exhaust pipe 74.

Therefore, the resistance of the solution flowing through the exhaust pipe 74 is reduced from the upstream section 22a by making the inner diameter dimension of the exhaust pipe 74 smaller than the inner diameter dimension of the downstream section 22b and sufficiently larger than the downstream section 22b. It is set so that most of the solution flowing into the container 72 flows to the downstream portion 22b. That is, the exhaust pipe 74 is a flow rate distribution conditional expression.
^{Σh = ΣkQ 2 = 0 ... (} 2) is set to a pipe shape that satisfies the equation.

For example, if the pressure loss of the exhaust pipe 74 is h and the inner diameter is D, from Manning's formula,
h = ^kQ 2 ... (3) equation Here, k is the ^{k = 10.20n 2 L / D 16/3} , L is the length of the exhaust pipe 74, Q is the flow rate, n represents at roughness coefficient, the exhaust pipe If 74 is vinyl chloride, glass or lead, it is 0.009 to 0.012.

FIG. 7 is a schematic diagram of the piping system of the deaerator 71, and the upstream portion 22a has an inner diameter of 4 mm and is supplied with a solution having a flow rate Q. The inner diameter of the exhaust pipe 74 is D ₁ , the length is L ₁ , the flow rate of the solution flowing through the exhaust pipe is Q ₁ , the inner diameter dimension of the recovery branch pipe 24 is D ₂ , the length is L ₂ , and the flow rate of the solution is Q _2. And

Then, 100 mm to _{L 1,} the _{L 2} 200 mm, the flow rate _{Q 2} of the solution flowing through the recovery branch pipe 24 when varied as shown in FIG. 8 the inner diameter of the exhaust pipe 74 by setting the _{D 2} to 4mm As a result, 80% of the solution supplied to the upstream portion 22a flowed when the inner diameter of the exhaust pipe 74 was 1 mm, and about 70% at 2 mm, and about 40% at 4 mm.

That is, by setting the lengths and inner diameter dimensions of the exhaust pipe 74 and the recovery branch pipe 24, the ratio of the solution supplied from the upstream portion 22a to the container 72 to the head 7 and the exhaust pipe 74 can be set. In this embodiment, Q ₁ : Q ₂ = 2: 8, preferably 1: 9. Thereby, since the solution from the upstream part 22a can be reliably flowed to the head 7, the head 7 can be surely degassed with the liquid for use.

  The supply tank 31 includes a tank body 81 as shown in FIG. The tank body 81 is formed in a cylindrical shape by a material such as glass that is difficult to attach bubbles or a material such as metal or ceramic that is relatively difficult to attach bubbles, that is, a material whose contact angle with the solution L is less than 10 °. In addition, an inverted conical funnel portion 82 that gradually becomes smaller in diameter and a small-diameter cylindrical portion 83 that continues to the funnel portion 82 are connected to the lower end. The material forming the tank body 81 is not limited.

  In the tank main body 81, a separation container 85 as a bubble separation means having a separation chamber 84 therein is accommodated and held by a holding member (not shown). The separation container 85 has an upper end surface and a front end surface opened by a material such as glass that does not easily attach bubbles, or a material such as metal or ceramic that does not easily attach bubbles, that is, a material having a contact angle with the solution L of less than 10 °. It is formed in an inverted cone shape. The lower end portion of the separation container 85 is inserted into the small diameter cylindrical portion 83 of the tank body 81 with a gap. The distal end portion of the separation container 85 is bent sideways, and the opened distal end surface 85 a is close to the inner peripheral surface of the small diameter cylindrical portion 83.

  The distal end of the supply branch pipe 34 penetrates the peripheral wall of the tank body 81 in an airtight manner and is connected to the inner peripheral surface of the upper part of the peripheral wall of the separation container 85 along the tangential direction. The proximal end of the solution supply pipe 21 is connected to the distal end of the small diameter cylindrical portion 83 of the tank body 81.

  The solution L supplied along the tangential direction from the supply branch pipe 34 into the separation container 85 falls while turning on the inner peripheral surface of the separation container 85 as indicated by an arrow in FIG. When the solution L swirls along the inner peripheral surface of the separation container 85, a centrifugal force acts on the solution L. Therefore, when the bubble L is included in the solution L, the bubble b is separated from the solution L due to the density difference between the bubble b and the solution L, gathers at the center of rotation, and floats in the separation container 85. If the atmosphere release pipe 35 connected to the upper surface of the tank body 81 is opened, the bubbles b floating in the separation container 85 can be diffused from the atmosphere release pipe 35 to the atmosphere.

  The solution L that falls while turning in the separation container 85 flows out of the front end surface 85 a and accumulates in the tank body 81. The liquid level of the solution L in the tank body 81 is controlled by the level sensor 50 so that the water head h (shown in FIG. 1) formed by the liquid level and the nozzle surface of the head 7 is constant.

  When the solution L flows out from the front end surface 85 a of the separation container 85, the solution L collides with the inner peripheral surface of the small diameter cylindrical portion 83 of the tank body 81. Therefore, even if the bubbles b remain in the solution L falling from the separation container 85, the bubbles b are separated from the solution L by causing the bubbles b to follow the inner wall of the tank body 81 at the time of collision, and the bubbles b float up in the tank body 81. Discharged.

In the coating apparatus configured as described above, the head 7 is deaerated before the solution is applied to the substrate W. In order to perform deaeration, an inert gas is supplied to the storage tank 32 through the gas supply pipe 46, and the solution stored in the storage tank 32 is pressurized. Thereby, the solution flows into the supply tank 31.

  When the pressure in the supply tank 31 is increased by continuing to supply the solution, the solution flows from the supply pipe 21 through the upstream portion 22a of the branch supply pipe 22 into the container 72 of the deaeration device 71. The solution flowing into the container 72 flows out from the downstream portion 22b and flows into the liquid chamber 12 of the head 7, and flows from the liquid chamber 12 through the branch recovery tube 24 to the recovery tube 23 together with bubbles remaining in the liquid chamber 12. . A part of the solution flowing into the liquid chamber 12 of the head 7 flows out from the nozzle 14. As a part of the solution flows out of the nozzle 14, a flow rate corresponding to the outflow amount is continuously supplied from the storage tank 32 to the supply tank 31.

  The proximal end of the recovery tube 23 is connected to the suction port 33 c of the aspirator 33. As the solution flows from the storage tank 32 to the supply tank 31, the suction port 33c of the aspirator 33 becomes negative pressure. As a result, the liquid chamber 12 of the head 7 is degassed, and the solution that has flowed into the recovery pipe 23 returns to the supply tank 31 through the aspirator 33. The solution returned to the supply tank 31 is supplied to the head 7 after being deaerated in the separation container 85 provided therein.

  If bubbles deaerated from the solution accumulate in the supply tank 31, they are dissipated into the atmosphere by opening the first opening / closing control valve 36 provided in the atmosphere opening pipe 35.

  In this way, the head 7 can be degassed while pressurizing and supplying the solution in the storage tank 32 to the supply tank 31, so that a predetermined amount of solution in the storage tank 32 is stored in the supply tank 31. Compared with the case where deaeration is performed by supplying the head 7, the time required for deaeration can be shortened. In addition, since a piping system as a pressurizing unit that pressurizes the solution in the supply tank 31 is not necessary, the configuration can be simplified.

Further, since the inside of the head 7 is deaerated while supplying the solution from the storage tank 32 to the supply tank 31, the volume of the supply tank 31 is sufficiently reduced, and the amount of the solution stored in the supply tank 31 is reduced. However, the deaeration in the head 7 is not hindered. That is, the supply tank 31 can be reduced in size.
If the inside of the head 7 is deaerated, at the same time, the piping through which the solution flows is also deaerated.

  On the other hand, the solution is supplied to the head 7 through the deaeration device 71. An exhaust pipe 74 is connected to the container 72 of the deaeration device 71. Therefore, the solution supplied to the deaeration device 71 may flow into the recovery pipe 23 through the exhaust pipe 74 without flowing into the head 7.

  However, the resistance of the solution flowing through the exhaust pipe 74 is sufficiently larger than the resistance of the solution flowing through the downstream portion 22 b of the supply branch pipe 22 to the head 7, for example, depending on the inner diameter size and length of the exhaust pipe 74. Set.

  Therefore, most of the solution supplied to the container 72 does not flow to the exhaust pipe 74 but flows to the head 7, so that the degassing in the head 7 can be reliably performed. That is, even if the solution supplied to the head 7 is degassed by the deaeration device 71 provided on the upstream side of the head 7, the degassing device 71 can surely degas the head 7. It can be prevented from disappearing.

  When the head 7 and the piping are degassed, the recovery on-off valve 26 provided on the outflow side of the head is closed, and the solution supplied to the head 7 is caused to flow out from the nozzle 14. Thereby, bubbles adhering to the nozzle 14 can be removed.

  Thus, if each part is deaerated, the liquid level of the solution in the supply tank 31 will be set so that it may become predetermined | prescribed water head h with respect to the surface in which the nozzle 14 of the head 7 was formed. Next, if the substrate W is transported by the table 3 and transported below the head 7, the drive unit 16 energizes the piezoelectric element 15, and the solution L supplied to the liquid chamber 12 of the head 7 is supplied from the nozzle 14. Spray onto the substrate W. Thereby, the solution L can be spray-coated on the substrate W.

  In the above embodiment, the case where the degassing apparatus of the present invention is applied to a coating apparatus for forming a polyimide film on a substrate has been described. The coating apparatus of the present invention can be used even in the case of supplying dropwise.

The side view which shows schematic structure of the coating device of the solution which concerns on one embodiment of this invention. The front view of the coating device which abbreviate | omitted the supply pipeline of the solution. Sectional drawing of a nozzle head. The bottom view of a nozzle head. Sectional drawing of a deaeration apparatus. Sectional drawing of a supply tank. The schematic diagram which shows each piping connected to the deaeration apparatus. The graph which measured the relationship between the quantity of the solution which flows into a collection pipe through a collection branch pipe, and the quantity of the solution which flows into an exhaust pipe, when the internal-diameter dimension and length of each piping shown in FIG. 7 are set.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 7 ... Head, 14 ... Nozzle, 21 ... Supply pipe, 23 ... Collection pipe, 31 ... Supply tank, 32 ... Storage tank, 33 ... Aspirator, 34 ... Supply branch pipe, 35 ... Atmospheric release pipe, 45 ... Third opening / closing Valve (pressurizing means), 46 ... gas supply pipe (pressurizing means), 71 ... deaeration device (deaeration means), 74 ... exhaust pipe.

Claims (5)

In a solution coating apparatus that sprays a solution onto a substrate,
A head having a nozzle for ejecting the solution by an inkjet method;
A storage tank storing the solution;
A supply pipe connecting the storage tank and the head;
A supply tank that is provided in the middle of the supply pipe and sets the height of the liquid level of the solution when spraying the solution onto the substrate;
Pressurizing means for pressurizing the solution stored in the storage tank when degassing the head and supplying the solution to the head through the supply tank;
An aspirator having an inflow port, an outflow port, and a suction port, and provided in the portion of the supply pipe between the storage tank and the supply tank via the inflow port and the outflow port;
A recovery pipe connected to the head and the suction port of the aspirator and supplied to the head and flowing through the head without being ejected from the nozzle; Application device for solution.   2. The solution coating apparatus according to claim 1, wherein bubble supply means for separating bubbles contained in the solution flowing through the supply tank through the aspirator is provided in the supply tank. Degassing of a head having a nozzle that ejects a solution to be applied to a substrate by an ink jet method, pressurizing the solution stored in a storage tank, and spraying the solution onto the substrate, the liquid level of the solution In the deaeration method performed by flowing the head through the supply tank that sets the height,
Pressurizing the solution stored in the storage tank and supplying it to the head through the supply tank;
Allowing the bubbles in the head to flow out together with the solution by flowing the solution through the head;
And a step of sucking the solution containing bubbles flowing out from the head by the flow of the solution supplied under pressure to the head and returning the solution to the supply tank. In a solution coating apparatus that sprays a solution onto a substrate,
A head having a nozzle for ejecting the solution by an inkjet method;
A storage tank storing the solution;
A supply pipe connecting the storage tank and the head;
A supply tank that is provided in the middle of the supply pipe and sets the height of the liquid level of the solution when spraying the solution onto the substrate;
Pressurizing means for pressurizing the solution stored in the storage tank when degassing the head and supplying the solution to the head through the supply tank;
A deaeration means provided between the supply tank and the head for removing bubbles contained in the solution flowing from the supply tank to the head;
A recovery pipe that is pressurized by the pressurizing means and flows from the degassing means through the head and from which the degassed solution flows out;
The degassing means and the recovery pipe are connected to discharge air bubbles degassed by the degassing means to the recovery pipe, and the solution pressurized by the pressurization means is passed to the head through the degassing means. An exhaust pipe having an inner diameter set so that only a part of the solution flows into the recovery pipe and most of the remaining solution flows into the head when the head is deaerated. A solution coating apparatus. In a degassing method for degassing a head having a nozzle that ejects a solution applied to a substrate by an inkjet method,
Degassing the pressurized solution with degassing means and supplying it to the head;
A step of degassing the inside of the head by flowing the solution supplied to the head through the head and outflowing into the collection tube;
Flowing the gas degassed by the degassing means through the exhaust pipe to the recovery pipe;
Applying only a part of the solution pressurized and supplied to the deaeration means to the exhaust pipe, and flowing most of the remaining solution to the head through the deaeration means. How to deaerate the device.

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