KR101416155B1 - Apparatus for drying substrate - Google Patents

Abstract

The substrate drying apparatus according to the present patent application includes a chamber for accommodating a substrate coated with a coating liquid and providing a space in which a drying process of the coating liquid is performed, and an organic solvent contained in the coating liquid by vacuum sucking air in the chamber Wherein the vacuum section comprises: an exhaust pipe having one end connected to the outside of the chamber; A vacuum pump connected to the exhaust pipe so as to suck and exhaust the space inside the chamber; And a pipe cooling device installed on the pipe of the exhaust pipe for rapidly cooling the installation area of the pipe.

In the above-described patent, the cooling device is installed on the duct of the exhaust pipe, the exhaust performance can be improved by inducing a pressure drop in the exhaust pipe, thereby achieving the maximum efficiency by using a small capacity vacuum pump So that the equipment cost is reduced.

Chamber, substrate, vacuum, cooling system

Description

[0001] APPARATUS FOR DRYING SUBSTRATE [0002]

This patent relates to a liquid crystal display device, and more particularly, to a substrate drying apparatus for drying a substrate coated with a coating liquid and a substrate drying method using the same.

(CRT), a liquid crystal display (LCD), an electro luminescence display (ELD), a vacuum fluorescence display (VFD), a plasma display panel (PDP), and the like have been developed in recent years, (plasma display panel) have been actively studied.

Among them, liquid crystal display device is a typical technology of flat panel display, and it has features such as thin type, low cost and low power consumption driving, and is used for lap top computer and pocket computer, The use thereof is rapidly expanding.

A liquid crystal display having such characteristics has a structure in which a color filter substrate, which is an upper substrate, and a TFT (Thin Film Transistor) array substrate, which is a lower substrate, are arranged to face each other and a liquid crystal having dielectric anisotropy is formed therebetween (TFT) added to hundreds of thousands of pixels through a pixel selection address wiring, and is driven by a method of applying a voltage to the pixel.

The liquid crystal display element is composed of a first substrate and a second substrate bonded together with a certain space, and a liquid crystal layer injected between the first substrate and the second substrate.

At this time, a pixel region P is defined by a plurality of gate lines arranged at one side of the first substrate at regular intervals and a plurality of data lines arranged at regular intervals in a direction perpendicular to the gate lines , A pixel electrode and a thin film transistor are formed in each pixel region (P).

The thin film transistor is formed at a portion where each gate line and a data line cross each other and is turned on / off according to a driving signal of the gate line to apply / not apply a video signal of the data line to / from each pixel electrode.

The second substrate includes a black matrix layer formed on the edge of the pixel region in order to shield the light except the pixel region, and an R, G, and B color filter layers corresponding to the pixel regions, , And a common electrode for forming an electric field together with the pixel electrode to control the liquid crystal layer arrangement is formed.

An alignment film (not shown) is formed on each of the first and second substrates facing each other and rubbed to align the liquid crystal layer.

In order to form various patterns on the first and second substrates, a photolithography technique is generally applied.

The photolithography technique involves coating a photoresist, which is a photosensitive material, on a film formed on a substrate, drying the photoresist to volatilize the solvent of the photoresist, soft-baking the photoresist at a relatively low temperature, After the photoresist is coated with a photomask, the photoresist film is exposed according to a pattern formed on the photomask, the exposed photoresist film is developed, and the developed photoresist is hard-baked at a relatively high temperature ), And each process of patterning the film quality exposed between the photoresist films proceeds through each device.

In this case, a general photoresist coating apparatus includes a coating section for coating a photoresist, which is a polymer material, on a substrate, a transport section provided with a robot arm for transporting the substrate coated with the photoresist to a drying section, And a drying section for volatilizing the solvent of the photoresist.

In the coating portion, a photoresist is coated uniformly over the entire area of the transparent substrate. A photoresist is dropped in the vicinity of the center of rotation, and the substrate is rotated at a high speed so that the photoresist is coated on the entire substrate by centrifugal force. A spinless coating method may be used which can coat the photoresist with a desired thickness from the beginning on the substrate using a coating method and a slit coater.

On the other hand, the substrate coated with the photoresist as described above is conveyed to the drying unit through the conveying unit. In the drying unit, heat and vacuum are generally used.

A vacuum pump is operated to vacuum the inside of the chamber to dry a part of the solvent, and then the heat is heated through the hot wire inserted into the hot plate.

In this state, the solvent of the photoresist of the substrate accommodated in the process chamber is volatilized by heat and vacuum and gradually dried.

1 is a schematic view for explaining a structure of a conventional substrate drying apparatus.

The conventional substrate drying apparatus as shown in the figure includes a chamber 10 for accommodating a substrate 11 coated with a coating liquid and providing a space for the drying process of the coating liquid to proceed, And a vacuum 20 for vacuuming the air to volatilize the organic solvent contained in the coating liquid.

The vacuum chamber 20 has an exhaust pipe 21 having one end connected to the outside of the chamber 10 and a vacuum connected to the exhaust pipe 21 for sucking and exhausting the inner space of the chamber 10 And a pump 23.

The exhaust pipe 21 has a main exhaust pipe 21a which is directly connected between the chamber 10 and the vacuum pump 23 and has a main exhaust pipe 21a which is branched from the middle of the main exhaust pipe 21a and forms a bypass And a slow exhaust pipe 21b. The slow exhaust pipe 21b serves to pre-depressurize the chamber 10 at a low speed before exhausting the main exhaust pipe 21.

When the vacuum exhaust by the main exhaust pipe 21 is performed immediately without the low-speed depressurization step using the slow exhaust pipe 21b, an abrupt pressure drop phenomenon occurs in the chamber 10, and this abrupt pressure drop occurs in the chamber 10, Thereby generating water vapor.

In addition, the abrupt pressure drop in the chamber 11 causes the substrate 11 to rapidly adsorb the substrate 11 in the downward direction, thereby causing an adsorption shock, thereby damaging the substrate 11.

At this time, the diameter of the tube of the slow exhaust pipe 21b is set to be relatively smaller than the pipe diameter of the main exhaust pipe 21a, so that the exhaust flow rate of the chamber 10 is controlled. The load becomes maximum.

Therefore, the vacuum pump 23 of the substrate drying apparatus is selected according to the vacuum efficiency at the time of slow exhaust.

However, in the above-mentioned prior art, there is a problem that the capacity of the vacuum pump is increased or the vacuum pump is additionally installed in order to improve the exhaust performance, thereby increasing the facility cost.

In addition, there is a problem in that the exhaust efficiency is lowered and it takes much time to dry the substrate, thereby deteriorating the productivity.

It is an object of the present invention to solve the above problems of the prior art, and it is an object of the present invention to provide a substrate drying device for improving exhaust performance of a vacuum pump, thereby enabling a vacuum exhaust in a chamber to be smoothly performed, and a substrate drying method using the same.

In order to accomplish the above object, the substrate drying apparatus according to the present patent includes a chamber for accommodating a substrate coated with a coating liquid and providing a space in which a drying process of a coating liquid is performed, A substrate drying apparatus comprising a vacuum to volatilize an organic solvent contained in a liquid,

An exhaust pipe having one end connected to the outside of the chamber; A vacuum pump connected to the exhaust pipe so as to suck and exhaust the space inside the chamber; And a pipe cooling device installed on the pipe of the exhaust pipe for rapidly cooling the installation area of the pipe.

Here, the exhaust pipe may include a main exhaust pipe connecting the chamber and the vacuum pump; And a slow exhaust pipe branched to bypass a predetermined section of the main exhaust pipe.

A first shutoff valve is provided on the branched main exhaust pipe side to shut off the main exhaust pipe so that the flow of the fluid is bypassed to the slow exhaust pipe. A second shutoff valve, which blocks the supply of the fluid on the bypass of the slow exhaust pipe, Valves can be installed.

At this time, a variable valve may be provided at a branch point between the main exhaust pipe and the slow exhaust pipe to change the flow of the fluid to the main exhaust pipe or the slow exhaust pipe.

The cooling device is a small refrigerator using refrigerant gas.

In particular, a cooling device may be installed on the duct of the slow exhaust pipe.

According to another aspect of the present invention, there is provided a method of drying a substrate, comprising: sealing a chamber in which a substrate coated with a coating liquid is introduced; Evacuating the inside of the closed chamber using a vacuum pump connected to an exhaust pipe; And a cooling step of operating the cooling device installed in the duct of the exhaust pipe to rapidly cool the duct of the exhaust pipe to induce a pressure drop inside the duct.

At this time, it is preferable that the cooling step is performed before the vacuum evacuation step.

Here, the vacuum evacuation step may include a slow evacuation step of evacuating the interior of the chamber at a low velocity and a low vacuum; And a main evacuation step of evacuating the interior of the chamber at a high speed and high vacuum after the slow evacuation step.

Also, it is preferable to perform a cooling step of rapidly cooling the duct of the slow exhaust pipe before the slow exhaust step.

In the above-described patent, the cooling device is installed on the duct of the exhaust pipe, the exhaust performance can be improved by inducing a pressure drop in the exhaust pipe, thereby achieving the maximum efficiency by using a small capacity vacuum pump So that the equipment cost is reduced.

This patent also has the effect of shortening the drying time due to the improvement of the exhaust efficiency.

2 is a schematic view showing the structure of a substrate drying apparatus according to the present patent.

The substrate drying apparatus as shown in the drawing mainly includes a chamber 100 and a vacuum chamber 200.

The chamber 100 accommodates the substrate 110 coated with the coating liquid and provides a space in which the drying process of the coating liquid proceeds. The chamber 100 has an opening and an opening for opening and closing the substrate 110, And the like.

In addition, the substrate 110 is transported using a separate transport robot (not shown).

The vacuum 200 sucks in the air in the chamber 100 to volatilize the organic solvent (e.g., solvent) contained in the coating liquid. The exhaust 100 is connected to the exhaust pipe A vacuum pump 230 connected to the exhaust pipe 210 for sucking / exhausting the internal space of the chamber 100 and an exhaust pipe 210 installed on a pipe of the exhaust pipe 210, And a pipe cooling device 250 for rapidly cooling the pipe.

Here, the exhaust pipe 210 may include a main exhaust pipe 211 and a slow exhaust pipe 213. The main exhaust pipe 211 directly connects the chamber 100 and the vacuum pump 230, Respectively.

Also, the slow exhaust pipe 213 branches a certain section of the main exhaust pipe 211 to form a bypass of the fluid.

The slow exhaust pipe 213 has a relatively small diameter as compared with the diameter of the main exhaust pipe 211. The reason why the slow exhaust pipe 213 having a relatively small diameter is formed is that the inside of the chamber 100 When vacuum exhaust is performed using a single exhaust pipe, rapid pressure drop and temperature drop phenomenon occur in the vacuum initial chamber 100 to generate moisture in the chamber or adsorption shock is applied to the substrate 110, So that the vacuum exhaust atmosphere in the chamber 100 is stabilized by performing the slow exhaustion for a predetermined time before the exhaustion.

That is, when vacuum exhaust is performed by using a vacuum pump of the same capacity as a large-diameter exhaust pipe and a small-diameter exhaust pipe, the exhaust flow rate is increased or decreased in proportion to the size of the opening diameter. This means that by reducing the exhaust flow rate, the abrupt pressure drop inside the chamber 100 can be reduced.

The vacuum exhaust using the main exhaust pipe 211 and the slow exhaust pipe 213 is controlled through the first shutoff valve 215 and the second shutoff valve 217.

The first shutoff valve 215 is installed on the side of the main exhaust pipe 211 at the branching point to block the channel of the main exhaust pipe 211 so that the flow of the fluid is bypassed to the slow exhaust pipe 213.

The second cutoff valve 217 is installed on the bypass line of the slow exhaust pipe 213 to cut off the channel of the slow exhaust pipe 213 and to direct the flow of the fluid to the main exhaust pipe 211 side.

The above-described flow path changing action of the first shut-off valve 215 and the second shut-off valve 217 can be performed in the same manner by providing the flow path variable valve at the branch point.

The pipe cooling device 250 may be provided with a small refrigerator using a refrigerant gas. The refrigerator may be installed to surround the pipe outer diameter of the exhaust pipe 210 to rapidly cool the predetermined installation area of the exhaust pipe 210, So that a temperature drop in the piping is achieved.

The temperature drop in the pipe leads to a pressure drop, which improves the exhaust performance of the vacuum pump.

The principle of pressure drop can be explained by the relation of gas molecule motion and temperature as follows.

First, the relationship between gas molecule motion and temperature is defined as E_k = 3 / 2RT. Where E_K is the kinetic energy, R is the gas constant, and T is the absolute temperature.

When we look at the relationship between gas molecular motion and Charles's law, the gas molecule kinetic energy (E_k) becomes proportional to the absolute temperature (T), the kinetic energy decreases as the temperature decreases, and the force The pressure drop is reduced.

Due to the pressure drop in the exhaust pipe 210, the vacuum pump 230 can easily exhaust gas molecules with reduced momentum even with a small energy. That is, the vacuum pump having the same capacity can exhibit a higher exhaust efficiency.

Since the cost of the vacuum pump used in the present invention increases as the capacity increases, it is advantageous in that the facility cost can be greatly reduced when a high exhaust efficiency can be obtained by using a low-capacity vacuum pump.

When the slow exhaust and the main exhaust are performed stepwise, the pipe cooling apparatus 250 obtains a higher exhaust efficiency in the case of being installed in the slow exhaust pipe 213. This is because the atmospheric pressure (760 Torr) in the initial slow- Pressure drop to 225 to 375 Torr and a pressure drop of up to 0.5 Torr in the main exhaust process.

That is, when the engine is slowly exhausted, the most load is applied to the vacuum pump 230, and if the exhaust efficiency during the slow exhaust is improved, the capacity of the motor required for the entire process can be designed to be low.

Hereinafter, a method for drying a substrate according to the present invention will be described.

First, a step of sealing the inside of the chamber 100 in which the substrate 110 coated with the coating liquid is carried out is performed. At this time, the pressure inside the chamber 100 has the same pressure as the atmospheric pressure.

The inside of the closed chamber is evacuated using a vacuum pump 230 connected to the exhaust pipe 210. The pipe cooling device 250 installed in the pipe of the exhaust pipe 210 for improving the exhaust efficiency, So as to induce a pressure drop inside the pipe of the exhaust pipe 210. [

Here, it is preferable that the cooling step using the tube cooling apparatus 250 is performed before the step of evacuating the vacuum, so that the evacuation is performed while the evacuation tube is sufficiently cooled.

In addition, the vacuum evacuation step may include a slow evacuation step of evacuating the interior of the chamber 100 at a low velocity and a low vacuum; And a main evacuation step of evacuating the interior of the chamber 100 after the slow evacuation step. In particular, it is preferable to perform a cooling step of rapidly cooling the channel of the slow evacuation pipe before the slow evacuation step.

The slow evacuation step may be performed for 3 to 5 seconds, and the main evacuation step may be performed for 20 to 30 seconds depending on the size of the substrate.

1 is a schematic view for explaining a structure of a conventional substrate drying apparatus;

2 is a schematic view showing the structure of a substrate drying apparatus according to the present patent.

Description of the Related Art [0002]

100: chamber 110: substrate

200: Generator 210: Exhaust pipe

211: main exhaust pipe 213: slow exhaust pipe

215: first shutoff valve 217: second shutoff valve

230: Vacuum pump 250: tube cooling device

Claims (10)

A chamber 100 for accommodating a substrate coated with the coating liquid and providing a space in which the drying process of the coating liquid proceeds; A vacuum pump 230 and a main exhaust pipe 211 connected to the chamber 100 from the vacuum pump 230 and sucking and exhausting the internal space of the chamber 100 and a main exhaust pipe 211 An exhaust pipe 210 made of a slow exhaust pipe 213 bypassing the exhaust pipe 210;  A first shutoff valve 215 installed in the main exhaust pipe 211 so that the flow of the fluid is bypassed to the slow exhaust pipe 213 by shutting off the channel of the main exhaust pipe 211; A second shutoff valve 217 provided on a bypass line of the slow exhaust pipe 213 to shut off the supply of the fluid; A pipe cooling device 250 installed on the pipe of the slow exhaust pipe 213 for rapidly cooling the internal temperature of the slow exhaust pipe 213; The pipe cooling device 250 cools the duct of the slow exhaust pipe 213 to lower the pressure inside the pipe and then the inside of the chamber 100 is discharged through the slow exhaust pipe 213 to the low- And then the second shutoff valve 217 cuts off the slow exhaust pipe 213 and exhausts the inside of the chamber 100 through the main exhaust pipe 211 at high speed and high vacuum. The method according to claim 1, Wherein the tube cooling apparatus (250) is a small refrigerator using refrigerant gas. 3. The method according to claim 1 or 2, Wherein the tube cooling apparatus (250) is installed to surround the outer diameter of the slow exhaust pipe. 3. The method according to claim 1 or 2, Wherein a variable valve is provided at a branch point between the main exhaust pipe (211) and the slow exhaust pipe (213) so as to change the flow of the fluid toward the main exhaust pipe (211) or the slow exhaust pipe (213). Sealing the inside of the chamber into which the substrate coated with the coating liquid is introduced; A pipe cooling device 250 installed in a slow exhaust pipe 213 bypassing the main exhaust pipe 211 connecting the vacuum pump 230 and the chamber 100 is operated to cool the pipe of the slow exhaust pipe 213 A cooling step of inducing a pressure drop inside the pipe; The inside of the closed chamber is evacuated by using a vacuum pump 230 connected to the exhaust pipe 210 while the inside of the chamber 100 is exhausted through the slow exhaust pipe 213 to the low- A vacuum evacuation step of evacuating the interior of the chamber 100 through the main exhaust pipe 211 to a main evacuation step of evacuating the inside of the chamber 100 at high speed and high vacuum; And drying the substrate. delete delete delete delete delete

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