JPH05264942A - Method and device for washing substrate after rubbing treatment - Google Patents

Abstract

PURPOSE:To prevent generation of uneven washing on the surface of a substrate by covering lamellately the whole surface of the substrate with pure water flowing on the substrate until the time point when washing is started. CONSTITUTION:The substrate washing device is constituted by providing successively and continuously a pre-stage treating chamber 10, an ultrasonic chamber 12, a spray washing chamber 14 and a draining chamber 16. Also, in each chamber thereof, carrying rollers 18 for carrying a substrate W are provided in one line. When the substrate W subjected to rubbing treatment is fed in, first of all, to the substrate W, pure water 28 is supplied in a form of curtain from a high pressure spray tube 20 in the pre-stage treating chamber 10, and the whole surface is covered lamellately and quickly with pure water being in a flowing state and is wetted. The pure water 28 is supplied to the surface of the substrate W from the high pressure spray tube 20 in the direction reverse to the substrate carrying direction, therefore, it does not occur that mist of the pure water sticks to the part on the surface of the substrate W which had already past through a flowing down position of the pure water 28 to cause unevenness, and in a washing process of the substrate, the orientation performance of an oriented film is maintained, and an LCD having averaged display quality can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a liquid crystal display device (LC
In the alignment film forming process in the manufacturing process of D),
The present invention relates to a method for coating a surface of a liquid crystal substrate with a polymer film such as polyimide, rubbing the film surface, and then cleaning the substrate surface, and a substrate cleaning apparatus used for implementing the method.

[0002]

2. Description of the Related Art As an alignment film for LCD, a polymer film such as polyimide is applied to the surface of a substrate so as to cover an electrode surface formed on a glass substrate, and the film surface is fixed with a cloth such as nylon or polyester. After rubbing by rubbing in the direction, the substrate surface is washed to remove shavings generated in the rubbing treatment. In this case, the substrate surface is cleaned by a method that does not change the alignment performance caused by rubbing, and conventionally, the substrate is cleaned and dried using a solvent such as isopropyl alcohol (IPA) or Freon. Was there.

However, the cleaning method using a solvent such as IPA or chlorofluorocarbon is a batch type treatment, and therefore, physical cleaning means utilizing high frequency waves or ultrasonic waves cannot be effectively used, and the solvent is not used. , Especially the use of CFCs is regulated, and there is a high possibility that CFCs will no longer be usable. For these reasons, recently, the type of cleaning device is changing to a single-wafer processing type using an aqueous cleaning liquid or pure water as a cleaning agent. For example, JP-A-3-6201
Japanese Unexamined Patent Publication No. 8 discloses a method of ultrasonically cleaning the surface of the alignment film with pure water. Further, in Japanese Patent Application Laid-Open No. 3-81730, scrubbing is performed on the surface of the alignment film in the same direction as the rubbing direction (a treatment of rubbing the surface of the alignment film with a brush, cloth, sponge, etc.) while flowing water on the surface of the alignment film. A method is disclosed.

[0004]

However, when the substrate surface after the rubbing treatment is cleaned with a cleaning liquid such as water or pure water, uneven cleaning often occurs on the substrate surface when the substrate surface begins to get wet with pure water or the like. However, the cleaning unevenness may remain on the substrate surface without disappearing.
As a result, the alignment performance of the alignment film changes, and the manufactured LC
The display quality of D will be greatly adversely affected. As a cause of uneven cleaning on the surface of the substrate, a polymer film such as polyimide forming the alignment film is coated with a surfactant such as a silane coupling agent on the underlying surface to enhance adhesion to the substrate. It is conceivable that a part of the substance may be eluted when the substrate is washed with water, and the eluted drug may be instantly adhered to the substrate surface to cause uneven cleaning.
The cleaning unevenness due to the elution of the surfactant may be eliminated by cleaning the substrate surface with a neutral detergent, but in the STN (Super Twisted Nematic) type LCD with a large tilt angle, it may depend on the detergent component. Detergent changes in tilt angle or alignment performance affect display quality, so detergents cannot be used in many cases.

The present invention has been made to solve the above problems, and in the case of cleaning the substrate surface after the rubbing treatment by a single-wafer treatment method using a cleaning liquid such as water or pure water. Further, it is a technical object to provide a substrate cleaning method capable of preventing the occurrence of cleaning unevenness on the substrate surface, and a substrate cleaning apparatus for carrying out the method.

[0006]

According to the present invention, before the cleaning liquid is supplied to the surface of the substrate after the rubbing treatment to clean the surface of the substrate, the substrate is cleaned while flowing pure water in a curtain shape. The pure water was moved relative to the pure water flow-down position, and the entire surface of the substrate was covered in layers with pure water flowing on the substrate until the cleaning was started. As described above, before the substrate surface is wet with a cleaning liquid such as pure water, the entire substrate surface is quickly wet with pure water in advance, and the entire substrate surface is covered with pure water in a layered state so that the silane is wet. Even if the elution of the surfactant such as the coupling agent occurs, it is difficult to adhere to the substrate surface, and the pure water is always flowing without staying on the substrate. It will flow down from the substrate.

Further, the substrate cleaning apparatus for carrying out the above-mentioned method comprises a pre-stage water supply means on the front side of the substrate cleaning means for supplying a cleaning liquid to the surface of the substrate after the rubbing treatment to clean the substrate surface. Is arranged, and the pre-stage water supply means supplies pure water to the surface of the substrate conveyed by the substrate conveying means in a curtain shape in a direction opposite to the substrate conveying direction. In this case, if the substrate transfer means is controlled so that the substrate transfer speed in the pre-stage water supply means is higher than the substrate transfer speed in the substrate cleaning means, the entire surface of the substrate is covered by the pure water supplied by the pre-stage water supply means. Will be wetted more quickly, which is preferable. Further, in this substrate cleaning apparatus, since pure water is supplied to the surface of the substrate which is being transported in the direction opposite to the substrate transport direction, the portion of the substrate surface that has passed through the pure water flow-down position In addition, it is unlikely that mist generated due to the supply of pure water adheres to cause unevenness on the substrate surface.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view showing an example of a schematic configuration of an apparatus for carrying out the substrate cleaning method according to the present invention. This substrate cleaning apparatus is configured by sequentially connecting a pretreatment chamber 10, an ultrasonic cleaning chamber 12, a spray cleaning chamber 14 and a draining chamber 16. Then, in each of these chambers, the substrate W
Conveying rollers 18 for conveying the are provided in a line.

A high-pressure spray pipe 20 is disposed in the pretreatment chamber 10 above the substrate transfer path. This high-pressure spray pipe 20 is connected to a pure water tank 24 storing pure water 22 by piping, and by driving a high-pressure pump 26, pure water is fed from the pure water tank 24 to the high-pressure spray pipe 20, Pure water is ejected from the nozzle of the high-pressure spray pipe 20 onto the surface of the substrate W. A plurality of nozzles of the high-pressure spray tube 20 are provided in parallel in a direction orthogonal to the transport direction of the substrate W, and pure water is applied to the surface of the substrate W in a curtain-like high pressure, for example, 1.8 kg / cm ² Let it flow down at a moderate pressure.
The high-pressure spray pipe 20 is installed above the substrate transport path so that the curtain-shaped pure water 28 is supplied to the substrate W transported by the transport rollers 18 in the direction opposite to the transport direction. ..

In the ultrasonic cleaning chamber 12, a plurality of ultrasonic cleaning devices 30 each having an ultrasonic generator and a spray tube are arranged in parallel along the transfer direction of the substrate W. The spray pipe of each ultrasonic cleaning device 30 is connected to a cleaning water tank 34, which stores cleaning water 32, through a pump 36 so as to be connected by piping. And
Ultrasonic cleaning device 30 from wash water tank 34 by pump 36
Cleaning the surface of the substrate W by applying high-frequency (megahertz) ultrasonic waves to the cleaning water sent to the cleaning water and supplying the cleaning water 38 that has been ultrasonically applied to the surface of the substrate W from the ultrasonic cleaning device 30. Is performed.

Further, in the spray cleaning chamber 14, there are conveyance rollers.
A spray tube 40 for supplying pure water 42 to the surface of the substrate W conveyed by 18 is provided. This spray pipe 40 is connected to a pure water supply source by a flow path. Pure water is supplied from the pure water supply source to the spray pipe 40 and the pure water tank 24. The water used after being sprayed from the spray pipe 40 and used for cleaning the surface of the substrate W is fed to the cleaning water tank 34 and reused as the cleaning water 32 for ultrasonic cleaning. There is. An air knife 44 connected to a pressurized air source is arranged in the draining chamber 16 provided adjacent to the spray cleaning chamber 14. Then, the pressurized air is blown from the air knife 44 toward the surface of the cleaned substrate W which has been transported from the spray cleaning chamber 14 into the draining chamber 16 by the transport roller 18, whereby the substrate W
The surface of the substrate W is drained, and after the draining, the surface of the substrate W is completely dried.

In the case of cleaning the surface of the substrate after the rubbing treatment using the apparatus having the above-mentioned structure, when the substrate W after the rubbing treatment is sent from a rubbing device (not shown), first,
In the pre-treatment chamber 10, the substrate W is supplied with pure water 28 in a curtain shape from the high-pressure spray tube 20, and the entire surface thereof is quickly covered with the pure water in a layered state to be wet. Therefore, even if a chemical such as a silane coupling agent applied as a base of the alignment film is eluted on the substrate, the chemical still remains
It does not stick to the surface of the substrate and flows down along with pure water from the substrate. In this case, the substrate transfer device including a large number of transfer rollers 18 is controlled to control the speed at which the substrate W is transferred in the pre-stage processing chamber 10 so that the ultrasonic cleaning chamber 12, the spray cleaning chamber 14 and the draining chamber are arranged in the subsequent stage. It is preferable to make it faster than the substrate transfer speed within 16 and in that case, the substrate W
The entire surface of is instantly covered with pure water in layers, which is more effective. Further, since the pure water 28 is supplied from the high-pressure spray tube 20 to the surface of the substrate W in the direction opposite to the substrate transport direction, the pure water 28 is purely applied to the portion of the surface of the substrate W that has passed through the flow-down position of the pure water 28. No mist of water adheres to cause unevenness. Then, the surface of the substrate W is covered with the flowing pure water in a layered manner and remains wet in the ultrasonic cleaning chamber 12
Since it is sent to the substrate, smoke-like cleaning unevenness unlike the conventional case does not occur on the substrate surface during the ultrasonic cleaning process.

The substrate cleaning method and apparatus according to the present invention are configured as described above, but the scope of the present invention is not limited by the above description and the contents of the drawings, and various modifications are possible without departing from the scope of the invention. May be included. For example, in the above embodiment, the method of cleaning the substrate while being transported in the horizontal direction has been described, but the substrate may be cleaned while being transported in the vertical direction. Further, as the substrate transfer means, those having various mechanisms such as a conveyor system and a nip roller system can be used. Further, in the above-mentioned embodiment, the pure water is supplied to the substrate surface from the high-pressure spray fixed while transporting the substrate, but the substrate is stopped and the high-pressure spray is moved in parallel along the substrate surface while the substrate surface is being moved. Pure water may be supplied to the. Further, the substrate transfer speed in the pre-treatment chamber, the ultrasonic cleaning chamber, the spray cleaning chamber, and the draining chamber is kept constant at a low speed, and the high-pressure spray is moved in the pre-treatment chamber along the substrate surface in the direction opposite to the substrate transport direction. The pure water may be quickly supplied to the entire surface of the substrate.

[0015]

Since the present invention is constructed and operates as described above, according to the substrate cleaning method of the present invention and the substrate cleaning apparatus of the present invention,
By the single-wafer processing method using a cleaning liquid such as water or pure water,
The substrate after the rubbing treatment can be cleaned without causing uneven cleaning on the surface of the substrate, and the alignment performance of the alignment film can be maintained in the process of cleaning the substrate to obtain an LCD with an averaged display quality.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a schematic configuration of an apparatus for carrying out a substrate cleaning method according to the present invention.

[Explanation of symbols]

 10 Pretreatment chamber 12 Ultrasonic cleaning chamber 14 Spray cleaning chamber 16 Draining chamber 20 High pressure spray pipe 22 Pure water 28 Pure water flowing in a curtain shape 30 Ultrasonic cleaning device 32 Cleaning water 40 Spray pipe 44 Air knife W After rubbing treatment substrate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuaki Yoshiya 1 at 480 Takamiya-cho, Hikone-shi, Shiga Dai Nippon Screen Mfg. Co., Ltd. in Hikone area (72) Inventor Akio Tsuchiya 480, Takamiya-cho, Hikone-shi, Shiga 1 Dainippon Screen Mfg. Co., Ltd. Hikone District Office

Claims (3)

[Claims] 1. A method for cleaning a substrate surface by rubbing a film surface of a polymer film formed on a surface of a liquid crystal substrate and then supplying a cleaning liquid to the surface of the substrate, wherein the surface of the substrate is cleaned before cleaning. In contrast, the substrate is moved relative to the pure water flow position while flowing pure water in a curtain shape, and the entire surface of the substrate is layered with pure water flowing on the substrate until the cleaning is started. A method for cleaning a substrate after a rubbing treatment, which is characterized by covering the substrate. 2. A substrate cleaning means for supplying a cleaning liquid to the surface of the liquid crystal substrate after the film surface of the polymer film formed on the surface is rubbed to clean the substrate surface, and a substrate for transporting the substrate. In a cleaning device for a substrate after rubbing treatment, which comprises a transport means, pure water is supplied to the front side of the substrate cleaning means in a curtain shape in a direction opposite to the substrate transport direction with respect to the surface of the substrate. An apparatus for cleaning a substrate after a rubbing process, characterized in that a pre-stage water supply means is provided. 3. The apparatus for cleaning a substrate after the rubbing process according to claim 2, wherein the substrate transfer speed of the substrate transfer means is set so that the transfer speed of the pre-stage water supply means is higher than the transfer speed of the substrate cleaning means.