JP3121520B2 - Local clean space - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a local clean space such as a clean booth or a clean bench formed by locally partitioning the inside of a clean room. The local clean space of the present invention can be used in a clean room for manufacturing an LCD (Liquid Crystal Display), for example, to perform various treatments while quickly removing static electricity generated in an insulating article represented by a glass substrate (LCD substrate) or the like. It is suitable as a space for performing.

[0002]

2. Description of the Related Art Today, an active matrix liquid crystal display (AM-LCD) using a TFT (thin film transistor) is used in a notebook personal computer and the like. The mass production of AM-LCD is based on the TFT process of depositing various thin films such as amorphous silicon, insulators, and conductors on a glass substrate, patterning them, and forming display electrodes and wiring for driving TFTs and liquid crystals. The method includes a panel process of aligning and overlaying a color filter (CF) substrate and injecting liquid crystal into a gap, and a module process of connecting a drive circuit IC around the panel and mounting a backlight or the like.

[0003] It is extremely important to eliminate static electricity in manufacturing LCDs. An LSI having a manufacturing process similar to that of an LCD is an LSI. However, the substrate material of the LCD is insulating glass, which is far less charged by static electricity than silicon single crystal (semiconductor), which is a substrate material of the LSI. This easily causes particles to be adsorbed and dielectric breakdown of the deposited film. Therefore, removing static electricity in manufacturing LCDs is much more important than in LSI manufacturing, and removing static electricity in LCD manufacturing has become the biggest issue for securing yield.

Further, LCD manufacturing has the following problems as compared with LSI manufacturing. That is, first,
Since the LCD substrate is rectangular, large, and heavy, batch processing is difficult and handling such as transportation is also difficult. Second, although pattern processing accuracy such as line width and line spacing is one order of magnitude less than that of LSI, uniformity of processing over a large area several times larger than that of a silicon substrate is required. Third, the concept of yield is different. That is, in a 10-inch class TFT-LCD corresponding to an LSI 1MDRAM, only two panels can be imposed on one glass substrate, and the yield can take only three values of 0%, 50%, and 100%. . This is in contrast to an LSI in which hundreds of chips can be arranged on one silicon substrate.

Various ionizers utilizing corona discharge have been conventionally disclosed as means for establishing countermeasures against static electricity in LCD manufacturing in consideration of the above-mentioned problems inherent in LCDs. Recently, a method has been developed in which air in the atmosphere around a charged object is irradiated with soft X-rays to ionize the air and neutralize the charge. The principle of these conventional static eliminations is to neutralize the charge by air ions generated by ionizing air (irrespective of corona or soft X-ray).

The present applicant has already filed an application for a liquid crystal ionizer utilizing corona discharge in Japanese Patent Application No. 5-88172. According to the ionizer disclosed in Japanese Patent Application No. 5-88172, charging of a large glass substrate carried on a transfer device is performed uniformly over the entire surface in three seconds without unevenness.
% Or more.

On the other hand, a recently-developed static eliminator using soft X-rays irradiates soft X-rays near a charged body to ionize air, and among the generated air ions, coulomb ions of opposite polarity to the charged ones. It is absorbed by a charged body by a force to remove the charge. Such a static eliminator has a characteristic that an air flow for transporting generated ions from a discharge electrode to a charged object is not required, which is indispensable for a corona discharge type ionizer. In addition, the corona discharge type ionizer combines and neutralizes positive and negative ions during transport until the ions reach the charged object, and the ion concentration is attenuated. Since air is directly ionized, high-concentration ions immediately after ionization reach the charged object without being attenuated, and thus have the characteristic that the charge elimination time is much shorter than in the corona discharge method.

[0008]

Since a corona discharge type ionizer carries air ions in an air stream, the ionizer disturbs the atmosphere around a charged object to be neutralized depending on the air flow speed, and is used in a clean room where the cleanliness is not very high. When used, there is a concern that dust deposited on the surrounding surface will fly up and stain the surface of the liquid crystal substrate.

On the other hand, a static eliminator using soft X-rays is a soft X-ray.
The lines are easily absorbed by the thin air layer,
In order to completely prevent exposure of the worker, it is necessary to cover the entire irradiation space with a 1 to 2 mm thick PVC plate or the like. Therefore, in the static eliminator using soft X-rays, since the liquid crystal panel is neutralized inside the closed space covered with the shielding plate, it is necessary to clean the closed space in addition to the clean room as a whole. For this reason, the static eliminator using soft X-rays loses the advantage of the conventional transport surface such that the liquid crystal substrate can be transported in an open state with respect to the clean air in the clean room.

[0010] Neither the corona discharge type ionizer nor the static eliminator using soft X-rays can prevent peeling charging and dielectric breakdown of the element occurring at that moment. Because, for example, in a large glass substrate transfer device, after the glass substrate is mounted on the conveyor belt and transferred, the glass substrate is lifted from the conveyor belt by the suction chuck of the transfer arm, but is mounted on the conveyor belt and transferred. If the glass surface and the belt surface slightly rub during the operation, the glass surface is positively charged and the belt surface is negatively charged. During transport, the oppositely charged surfaces are in close contact with each other, so they are apparently in a neutralized state.However, when the glass substrate is lifted from the conveyor belt by the suction chuck and both surfaces are separated, peeling charging occurs. An electric field due to positive charging appears instantaneously in the thickness direction of the glass substrate, and an element formed on the glass substrate causes dielectric breakdown. This dielectric breakdown cannot be prevented.

A corona discharge type ionizer and a soft X
A device that neutralizes the charge by air ions, such as a static eliminator using a wire, requires 0.5 seconds to several seconds to remove the charge generated on the glass substrate by the peeling charge, and prevents the dielectric breakdown of the element. Is useless. Then, in the case where the charge generated on the glass substrate is to be neutralized by using air ions, for example, when air ions are adsorbed on one surface of the glass substrate, the charge is generated on the other surface of the glass substrate by peeling charge. A charge having a polarity different from the charge is generated on one surface of the glass substrate. Since the electric field converges only inside the glass substrate, the charge is apparently neutralized, but it causes deterioration of elements inside the substrate and uneven alignment of liquid crystal molecules.

Furthermore, in both the corona discharge type ionizer and the static eliminator using soft X-rays, the range of static elimination per unit is limited, so that charging occurs in a clean room for manufacturing liquid crystal panels. When there are a plurality of places where there is a possibility of performing the operation, a static eliminator must be installed in all of them. Therefore, costs increase and maintenance becomes complicated.

An object of the present invention is to provide a means for easily and instantaneously removing static electricity generated in an insulating article such as a glass substrate required for manufacturing an LCD.

[0014]

In order to solve the above-mentioned problems, a local clean space constructed according to the present invention is a local clean space formed by partitioning the inside of a clean room using partitions. The partition is provided with an opening for bringing in the article into the local cleaning space and an opening for taking out the article from the local cleaning space, and humidifying means for humidifying the inside of the local cleaning space, and a pressure in the local cleaning space. It was evacuated from the local clean space outside so as locally clean space lower than the atmospheric pressure the clean room, the clean room
Exhaust means for allowing the air inside to flow into the local clean space through the opening .

This local clean space includes, for example, an LCD substrate.
The space to process. Further, a processing space may be formed in the local cleaning space, and an air supply means for circulating and supplying the air in the local cleaning space may be provided in the processing space. In this case, it is desirable that the air circulated and supplied into the processing space by the air supply means be rectified. In addition, filter
A filter may be provided.

[0016]

As a result of various studies and considerations, the present inventors have found that the resistance of the glass surface from which surface deposits (particularly organic substances) have been removed by ultraviolet / ozone cleaning is considerably lower than the resistance before cleaning. Further, it has been found that the surface resistance can be significantly reduced by increasing the relative humidity around the clean surface. Based on this finding, the applicant of the present application disclosed in Japanese Patent Application Nos. 5-240676 and 5-292683 that grounding a substrate supporting surface in contact with a clean glass substrate while maintaining a high relative humidity atmosphere. Means for removing the peeling charge by transporting the same substrate therein has been disclosed. The present invention also utilizes this finding as in the previous application, but in the present invention, the inside of the local clean space formed in the clean room is made to have a high relative humidity by using a humidifying means, so that an insulator article or the like can be obtained. It is characterized by easily and instantaneously removing static electricity generated in the device. When the humidity in the air is extremely large (relative humidity is 80% or more), a phenomenon of static charge decay due to so-called "air leakage" occurs, in which static charges on the surface of the object leak directly into the air. In the local clean space of the present invention, by setting the relative humidity inside to a high value of 80% or more, it is possible to reduce the surface resistance of an insulating article or the like by utilizing the air leakage.

The reason why the surface charge of an insulating article or the like can be remarkably attenuated by increasing the relative humidity in the air in the local clean space is that the surface resistance value increases when the amount of water adsorbed on the surface of the insulating article increases. Is reduced. For example, SiO ₂ atoms, which are the main components of a glass substrate, have a lone pair of electrons and easily form hydrogen bonds with H of water molecules, so that a water molecule layer is easily formed on the glass surface. In addition, ceramic materials such as SiO ₂ , SiN, and Al ₂ O ₃ that are often used for the contact surface of the substrate support portion contain O and N atoms having a lone pair of electrons. Also has the property of easily hydrogen bonding with H of water molecules to form a water molecule layer on its surface. In addition, TFT-LCD
In the manufacturing process, a thin-film electrode, an insulating film, etc. are formed on a glass substrate to protect a plurality of layers of electrodes with the insulating film, and the step of forming the insulating film in the TFT-LCD process is occupied. Although the ratio is large, these insulating films
N, SiO ₂ , Al ₂ O ₃ , Ta ₂ O _5, etc. These O and N atoms of the insulating film also have such a lone pair of electrons as the O atoms of SiO _2. When the relative humidity increases even for a glass substrate with an insulating film, the amount of water adsorbed on the surface increases, so that the surface resistance value can be reduced. Then, the charge of the glass substrate or the like instantaneously leaks to the ground side through the glass substrate surface whose surface resistance value has been lowered due to being placed in an atmosphere having a high relative humidity and the grounded substrate support. Furthermore, when the relative humidity of the local clean space is set to 80% or more, the charge on the glass substrate surface is effectively attenuated due to air leakage, and the charge on the glass substrate surface can be more effectively removed. Becomes As described above, according to the present invention, the local clean space formed in the clean room is made to have a high relative humidity, so that the static electricity generated on the insulating substrate or the like can be instantaneously removed.

The local clean space of the present invention is formed by partitioning the inside of the clean room using partitions. Then, the inside of the partitioned local clean space is humidified by the humidifying means. The partition may be made of a rigid material such as metal, plastic or glass, or a flexible material such as vinyl or woven fabric. In short,
What suffices as long as it can partition a local space partitioned from the surroundings in a clean room.

Further, the partition is provided with an opening for carrying articles into the local cleaning space and an opening for taking articles out of the local cleaning space. However, a configuration may be adopted in which the carry-in opening and the carry-out opening are used in common. An article such as a glass substrate is carried into the local cleaning space through these openings, and after performing predetermined processing in the local cleaning space, the article is carried out of the local cleaning space through the opening.

On the other hand, when an opening is provided in the partition,
There is a concern that moisture will leak out of the local clean space through the opening. Leakage of water will increase the relative humidity of the entire clean room. In order to prevent this, air is constantly exhausted from the local cleaning space so that the pressure in the local cleaning space is kept lower than the pressure in the clean room outside the local cleaning space. Then, air with high humidity does not leak out of the local clean space, and moisture does not leak.

Further, a processing space may be formed in the local cleaning space, and air supply means for circulating and supplying the air in the local cleaning space may be provided in the processing space. In this case, the air circulated and supplied into the processing space by the air supply means is preferably rectified. By setting the processing space in a rectifying state, problems such as accumulation of dust and dust generated when processing the articles in the processing space and re-floating can be solved, and the articles can be processed with high cleanliness. become. However, if the entire inside of the local clean space is configured to be in a rectified state, equipment costs increase. Therefore, it is preferable that a processing space for processing articles is formed in the local cleaning space, and only the processing space is set in a rectified state. By doing so, the facility cost can be made easier and the air volume can be made smaller, so that the operating cost can be made smaller. Note that the size, size, shape, and the like of the processing space may be appropriately changed according to the content of the processing.

Further, a filter may be provided in the air supply means. Then, in the processing space formed in the local cleaning space, the article can be processed in a clean atmosphere filtered by the filter. In particular, a ULPA filter (ultra
By incorporating a low penetration air filter), fine particles in the air supplied to the processing space can be removed with high accuracy, and contamination of the insulating substrate and the like can be more reliably prevented. However, the filter does not necessarily need to be built in the air supply means, and the mounting position of the filter can be freely set. For example, the air supply means and the filter may be separately arranged so that a clean atmosphere can be circulated and supplied into the processing space.

[0023] Further, the air volume supplied to the processing space by the air supply means is configured to be adjustable so that the amount of air supplied to the processing space and the temperature of the air can be adjusted according to the handling environment such as the insulating substrate. It is preferable that the temperature of the air be adjustable.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings.

A. First, when the humidity in the local space is
The influence on the leakage property of the charged charge of the glass substrate for CD was examined. The experimental results will be described.

1. Experimental method Measure the change over time of the surface potential of the glass substrate when the polyvinylidene chloride film is contacted and peeled to each of the grounded glass substrate and the grounded glass substrate. Examined.

(1) Experimental Materials The glass substrates used in the experiments were all alkali-free glass (Fusion 7059) manufactured by Corning.
Its relative dielectric constant is 5.84 [-], and its component is Si
O ₂ : 49%, BaO: 25%, B ₂ O ₃ : 15%, A
l ₂ O ₃ : 10%, others: 1%. The sizes of the glass substrate and the release material used in the experiment are as follows. Glass substrate: CORNING # 7059 300 mm x 400 mm x 1.1 ^t mm Release material: polyvinylidene chloride film Kureha Chemical (trade name: Kurerap) 100 mm x 100 mm

(2) Cleaning of Glass Substrate After rinsing the glass substrate with running ultrapure water, the front and rear surfaces were cleaned with ultraviolet / ozone (UV / O ₃ ) for 10 minutes.

(3) Measurement of Surface Potential In a constant temperature / humidity chamber, the glass substrate was placed at four locations with Teflon legs and placed. When the glass substrate was grounded, the lead was grounded to the side of the glass substrate supported by the Teflon legs, and the lead wire was grounded by crocodile clips. The probe of the surface electrometer was arranged on the lower surface of the glass substrate. Then, the time-dependent change in the surface potential of the glass substrate when the polyvinylidene chloride film was peeled off at the center of the upper surface of the glass substrate was recorded in 1/100 second increments. The measurement was performed under the condition that the temperature in the tank was 23 ° C. (constant) and the relative humidity was changed to 40%, 60%, 70%, and 80%.

2. Experimental Results (1) When not grounded As shown in FIG. 1, when the polyvinylidene chloride film was contact-peeled from a clean (immediately after UV / O ₃ cleaning) glass substrate, the surface potential reached the maximum value at the moment of peeling. (Hereinafter referred to as “instantaneous maximum surface potential”). After that, although the surface potential attenuated, the surface potential of 8 kV to 9 kV remained in any case without grounding, regardless of the value of the relative humidity. On the other hand, the instantaneous maximum surface potential tended to decrease as the relative humidity increased. In FIG. 1, the time at the moment of peeling is shown shifted in order to make it easy to distinguish the change over time of the surface potential at each relative humidity.

Clean (U) in an atmosphere having a relative humidity of 40%
When the polyvinylidene chloride film is contact-peeled from the glass substrate (immediately after the V / O ₃ cleaning), the instantaneous maximum surface potential of the glass substrate reaches about 23 kV at the moment of peeling, and then attenuates to about 9 kV within one second. To a steady state. On the other hand, when the contact peeling is performed in an atmosphere with a relative humidity of 80%, the instantaneous maximum surface potential is about 9 kV (40
% RH at 60%), but the surface potential was hardly attenuated after that, and a steady state was reached.

(2) Case of Grounding On the other hand, a clean (UV) grounded at one place with an alligator clip
When the polyvinylidene chloride film was contact-peeled from the glass substrate (immediately after / O ₃ cleaning), as shown in FIG.
The surface potential of the glass substrate became maximum at the moment of peeling, and gradually decreased with time thereafter. Also,
As the relative humidity increased, the instantaneous maximum surface potential decreased. For example, when the glass substrate is peeled off in an atmosphere of 40% relative humidity, the instantaneous maximum surface potential of the glass substrate is about 23 kV, and the time until the instantaneous maximum surface potential value attenuates to 1/10 (hereinafter “1/10 The decay time was about 5.1 seconds. On the other hand, when the polyvinylidene chloride film is contact-peeled from the grounded glass substrate in an atmosphere with a relative humidity of 80%, the instantaneous maximum surface potential is about 6 kV (4 kV).
75% at 0% RH), and the 1/10 decay time was about 0.4 seconds (93% decrease).

FIG. 3 shows how the potential decay rate changes when the number of grounding points is increased to a maximum of eight under the condition of 80% RH. When eight locations are grounded, the instantaneous maximum surface potential is reduced by 12% (approximately 5k) as compared with the case where only one location is grounded.
V), and the 1/10 decay time is reduced by 62% (about 0.14
Seconds).

Table 1 summarizes the experimental results of FIGS.

[0035]

[Table 1]

From the above, the following has become clear regarding the peeling and charging phenomenon of a clean grounded glass substrate. The high humidity atmosphere has the effect of reducing the instantaneous maximum surface potential and increasing the decay rate of the charged potential. Increase in the number of ground locations of the glass substrate has the effect of increasing the charge collecting position decay rate.

(3) Comparison with soft X-ray static elimination FIG. 4 shows that soft X-rays are irradiated in an atmosphere at a relative humidity of 40% and are not grounded and are clean (immediately after UV / O ₃ cleaning).
3 shows a change with time of the surface potential of the glass substrate when the polyvinylidene chloride film is peeled off from the glass substrate.
The instantaneous maximum surface potential value in FIG. 4 is about 12.5 kV, which is almost equal to the instantaneous maximum surface potential value (13.3 kV) at 60% RH of the single-ground glass substrate in FIG. Further, the 1/10 decay time in FIG. 4 is about 0.29 seconds, which is 80% R of the three-grounded glass substrate in FIG.
H is approximately equal to 1/10 decay time (0.22 seconds). That is, the performance when static electricity is removed in a humidified atmosphere with the clean glass substrate grounded is sufficiently higher than the soft X-ray static electricity removal performance.

B. Next, based on the above findings, a local clean space according to the present invention was constructed. The local clean space of the embodiment will be described below.

1. Configuration of local clean space (1) Local clean space using vaporizing humidifier FIG. 5 shows a local clean space 1 actually configured in the embodiment.
6 is a schematic front view, and FIG. 6 is a plan view thereof. As shown in the figure, a local clean space 1 was formed by partitioning the inside of a clean room 2 using a partition 3. The local clean space 1 created in the example is 1800 × 2
The size is 400 × 2050 ^h mm ³ and the internal volume is 8.2
It was m ^3. Partition 3 used a vinyl sheet. The partition 3 is provided with an opening 4 for carrying articles into the local clean space 1 and an opening 5 for carrying articles out of the local clean space 1 to form a transport line as shown in FIG.

Then, the inside of the local clean space 1 is further partitioned by a partition 7 to form a processing space 8 for processing articles.
Is formed, and the articles are conveyed in the order of the opening 4 → the processing space 8 → the opening 5 in the aforementioned conveying line. The processing space 8 created in the embodiment is 1200 × 240
The size was 0 × 1300 ^h mm ³ . In addition, partition 7
Used a vinyl sheet as in partition 3.

Above the processing space 8 in the local cleaning space 1, a fan filter unit (Fan Filter Unit: hereinafter referred to as “FFU”) as air supply means for circulating the air in the local cleaning space 1 into the processing space 8. ), And a processing space 8 was formed by partitioning immediately below the partition 6 with a partition 7 made of a vinyl sheet. In addition, FFU means a blower as an air supply means and a HEPA filter (High Eff) as an air filtration means.
civicity Particulate Air Filter). In this embodiment,
Four FFUs were used. The FFU used in the examples includes
There is an air volume adjustment means that can switch the tap of the blower (sirocco fan) to achieve four levels of air volume: fine, weak, medium, and strong. The main performance specifications per FFU are single-phase 2
At 00 V and an external static pressure of 10 mmAq, a breeze of 6 m ³ /
min.127W, weak wind 10m ³ /min.162W,
Medium wind 12m ³ / min ・ 182W, strong wind 15m ³ / min
・ It is 216W. In this embodiment, the HEPA filter contains 99.999% of fine particles having a particle diameter of 0.3 μm or more.
A material having a performance capable of removing the above was used.

The FFU 6 is attached to the entire upper part of the processing space 8 so that the flow of air circulated and supplied into the processing space 8 is rectified. If the inside of the processing space 8 is not rectified, turbulence and turbulence in the processing space 8 easily occur, and dust generated when processing articles inside the processing space 8 may circulate and accumulate in the processing space 8. There is. On the other hand, by setting the inside of the processing space 8 in a rectified state, generated dust and dust can be continuously removed by an air current, so that articles can be processed with a high degree of cleanliness. In this embodiment, since a series of handling such as loading, processing, and unloading of articles is performed in the vertical rectification space (processing space 8) immediately below the clean air blowout of the FFU 6, dust generated at the time of article handling is continuously reduced. It has the characteristic that it can be removed and the recovery from the contamination state is quick.

The humidifier 1 is located inside the local clean space 1.
The humidified air created at 0 was supplied using a humidifying fan 11 to humidify the inside of the local clean space 1. The humidifier 10 used in this embodiment is a vaporized humidifier as shown in FIG.
The inside of the local clean space 1 was configured to be humidified to a desired relative humidity. The evaporative humidifier is a method in which water is supplied from a water supply header 12 to a humidifying material 13, while water is vaporized and evaporated by passing air through the humidifying material 13 to produce humidified air. The size of the humidifying material 13 (media) is 375 × 400 × 150 ^t mm, and the humidifying capacity is 6.2 kg / h at maximum (inlet air 23 ° C./40% R).
H, wind speed 3 m / s), and steady at 2.0 kg / h (inlet air 23 ° C./80% RH, wind speed 3 m / s). The humidifying fan 11 is a single suction sirocco fan No. 1 1/2 (EBARA SMMII) and the motor of the humidifying fan 11
00 V and 0.5 kW.

As shown in FIG. 5, an electric signal of a humidity detector 15 arranged in the processing space 8 was taken into a PID indicating controller 16, and an inverter 17 controlled the number of revolutions (blowing amount) of the humidifying fan 11. Feedback control was performed while measuring the relative humidity with the humidity detector 15 to adjust the amount of humidified air to bring the humidity in the processing space 8 closer to the target value. In addition,
The humidity detector 15 is a capacitance type sensor (VAISALA).
133Y), and the PID indicating controller 16
4 (Tokimec), and the inverter 17
OL U100 (Mitsubishi Electric).

Further, the temperature-controlled air created by the temperature control means 20 is supplied into the local clean space 1 by using a fan 21 so that the inside of the local clean space 1 can be adjusted to a desired temperature. As shown in the figure, an electric signal from a temperature detector 22 disposed in the processing space 8 was taken into a PID indicating controller 23, and the amount of cooling water sent to a coil 25 in the temperature control means 20 was controlled by a motor valve 24. Feedback control was performed while measuring the temperature with the temperature detector 22 to adjust the amount of cooling water sent to the coil 25, thereby bringing the temperature in the processing space 8 closer to the target value. The temperature control means 20 was mainly used for removing the heat generated by the FFU 6 and preventing the temperature inside the processing space 8 from rising. The cooling capacity is 1100 kcal / hr,
The temperature detector 22 was a platinum resistance temperature detector. The PID indicating controller 23 is the RIS 24 (Tokimec) as before.

An exhaust fan 26 is provided below the local clean space 1 to exhaust air from the local clean space 1.

(2) Local clean space constructed by providing a water tank at the bottom In FIGS. 5 to 7 described above, an embodiment in which the inside of the local clean space 1 is humidified by using the vaporizing humidifier 10 is described. explained. FIG. 8 is different from the embodiment shown in FIG.
An embodiment in which the inside of the local clean space 1 is humidified by using steam in a water tank 30 provided at the bottom will be described.

Similarly, in the embodiment shown in FIG.
The inside of the clean room 2 is partitioned by partitions 3 to form a local clean space 1. Further, the inside of the local clean space 1 is further partitioned by a partition 7 and a processing space 8 is formed.
Is formed, and an FFU 6 is disposed above the above. The partition 3 has an opening 4 for carrying insulated articles into the local clean space 1 and an opening 5 for taking out the insulated articles from the local clean space 1.
As shown in FIG. 2, a transport line for transporting articles in the order of opening 4 → processing space 8 → opening 5 is formed. Further, by supplying the temperature-controlled air created by the temperature control means 20 to the inside of the local clean space 1 by the fan 21, the heat generation of the FFU 6 is removed and the temperature rise in the processing space 8 is prevented. The electric signal of the temperature detector 22 arranged in the controller 8 is taken into the PID indicating controller 23 and the motor valve 24
The point that the amount of cooling water sent to the coil 25 in the temperature control means 20 is controlled by the above-described method, and the point that an exhaust fan 26 is provided below the local clean space 1 to exhaust air from the local clean space 1 is also considered. Has the same configuration as that of the embodiment shown in FIG.

However, in the embodiment shown in FIG.
There is no equivalent of the humidifier 10 previously described in FIGS. 5 to 7, and instead, a water tank 30 is provided at the bottom of the local clean space 1. Therefore, the embodiment shown in FIG. 8 is configured to circulate the air humidified by the steam generated from the water tank 30 in the local clean space 1 to humidify the inside.

2. Next, the operation is actually performed in the local clean space 1 using the vaporizing humidifier 10 described with reference to FIGS.
The controllability of humidity in the room was investigated. The results are described below.

(1) Purpose of the Experiment The purpose of the experiment was to examine the humidity controllability of the local clean space 1. Specifically, the sizes of the openings 4 and 5 were variously changed, the humidity controllability in the processing space 8 under different ventilation conditions was examined, and the relationship between the opening size and the ventilation volume was examined.

(2) Experimental Conditions The openings 4 and 5 are formed as described with reference to FIGS.
In the partition 3 partitioning the local clean space 1, the partition 3 is formed at two places, that is, the carry-in side and the carry-out side. Opening 4
And the size of the opening 5 was as follows.

(3) Measurement Items The measurement items are the humidity controllability and the ventilation volume (the suction volume of the exhaust fan 26).

(4) Results [Humidity controllability] The measurement results are shown in FIG. 9 (opening size: fully closed), FIG. 10 (opening size: 500 × 500 mm ² ),
It is shown in FIG. 11 (opening size: 500 × 800 mm ² ). The temperature and humidity of the clean room 2 outside the local clean space 1 are maintained at 23 ° C. and 45% RH in each case, and the temperature and humidity in the local clean space 1 and the processing space 8 are also
At the start of operation, the temperature and humidity are the same. The target values of temperature and humidity in the processing space 8 are set to 23 ° C. and 80% R
When the operation was started at H, the local clean space 1 reached a range of 80 ± 0.3% RH within 15 minutes after the start of operation.

Various changes were made to the target value of the humidity (40% R
H to 90% RH), the following humidity controllability was obtained irrespective of the opening size and the set humidity. Rise time to set humidity: within 15 minutes Overshoot: within 3.5% RH Regular: Within ± 0.3% RH

It was found that the relative humidity in the processing space 8 reached the set value in a short time after the start of operation. After reaching the set value, the relative humidity is extremely stable, so that the insulating substrate can be continuously handled in the processing space 8.

[0057] the ventilation (suction amount of the exhaust fan 26) air volume of FFU6 shown in FIG. 5, middle (12m ³ / min ·
182 W), the air volume of the humidifying fan 11 is 1600 m ³ / h, 1000 m ³ / h, 400 m ³
/ H, the air in the local clean space 1 is changed to the air in the atmosphere (clean room 2) outside the local clean space 1 in a state of zero ventilation (zero suction volume of the exhaust fan 26). The amount (ventilation volume) to be replaced was examined. FIG. 12 shows the measurement results. That is, the amount of moisture contained in the humidified air in the local clean space 1 corresponding to the ventilation amount leaks to the atmosphere around the local clean space 1 (the clean room 2) through the openings 4 and 5. If left unchecked, the relative humidity of the clean room 2 will continue to increase. Therefore, in order to prevent such inconvenience, in the present invention, the inside of the local clean space 1 is exhausted by the exhaust fan 26 with an exhaust amount corresponding to the ventilation amount in FIG. By providing the exhaust fan 26, the pressure inside the local cleaning space 1 is kept slightly lower than the pressure of the atmosphere around the outside of the local cleaning space 1 (the clean room 2). In accordance with the pressure difference between the inside and outside of the local clean space 1, the air in the surrounding clean room 2 passes through the openings 4 and 5 and the local clean space 1
However, an amount corresponding to the amount of inflow air is exhausted to the outside of the local clean space 1 by the exhaust fan 26. Thus, a high humidity atmosphere (for example, 23 ° C., 80
% RH) is prevented from leaking into the low humidity atmosphere (for example, 23 ° C./45% RH) of the surrounding clean room 2.

C. Specific Application Example of the Present Invention Next, an example will be described in which the local clean space of the present invention is applied to a surface inspection line of a glass substrate in manufacturing a liquid crystal flat panel display and a rubbing step.

1. Surface Inspection Line In a surface inspection line of a glass substrate in the production of a liquid crystal flat panel display, a transfer robot, a cassette case containing the glass substrate, and a surface inspection device (dust inspection) are installed. The transfer of the glass substrate between the cassette case and the surface inspection device is performed by the arm of the transfer robot. The nominal cleanliness of the clean room in which such a surface inspection line is provided (directly below the ceiling HEPA filter) is usually class 10 (0.
Number concentration of particles larger than 3 μm in space is 10 particles / ft.
³ or less) and high. However, dust is generated due to sliding of parts in the transfer robot and friction when a glass substrate is loaded and unloaded from the cassette case, and the cleanliness of the surrounding atmosphere is locally deteriorated to a class of 1,000. When the glass substrate is taken out or carried in by the transfer robot, peeling charge is always generated on the glass substrate. If this situation is left unchecked, dust particles will be electrostatically adsorbed on the surface of the charged glass substrate. In this case, when the glass substrate is inspected for dust, new particle contamination occurs at the inspection stage, and an inspection failure occurs. Therefore, an example in which the present invention is applied to such a surface inspection line to prevent static electricity will be described while showing data on the charge of the glass substrate and the amount of dust attached thereto, in comparison with the prior art.

(1) Comparative Example In a normal clean room (23 ° C., 45% RH, class 10), a glass substrate (300 mm × 400 mm × 1.1 ^t mm) after wet cleaning is removed from a cassette case by a transfer robot. When the glass substrate was carried into the surface inspection apparatus, the glass substrate was charged to 5 kV and 80 particles having a size of 1 μm or more adhered. If at least one particle of 1 μm or more adheres, the glass substrate is determined to be defective.

(2) Example of the Present Invention FIG. 13 schematically shows an example in which a surface inspection line for the glass substrate 40 is installed in the local clean space 1 of the present invention. Inside the local cleaning space 1, a cassette case 41 for storing a predetermined number of glass substrates 40 carried through an opening 4 formed in the partition 3 is placed. The glass substrate 40 is taken out one by one from the cassette case 41 by the arm of the transfer robot 42, and the glass substrate 40 is carried into the surface inspection device 43 to perform dust inspection. Further, the glass substrate 40 after the inspection is taken out of the surface inspection device 43 and returned to the cassette case 41. Four FFUs 6 each having a built-in HEPA filter are installed on the ceiling of the local clean space 1.
Inside, clean air (class 10) adjusted to a predetermined humidity and temperature (23 ° C., 70% RH) is supplied, and the inside of the local clean space 1 is maintained in a rectified state.

In the local cleaning space 1, the transfer robot 42 performs the wet cleaning on the glass substrate 40 (3).
00 mm × 400 mm × 1.1 ^t mm) was taken out of the cassette case 41 and carried into the surface inspection device 43. As a result, the charging of the glass substrate 40 was suppressed to 50 V or less, and
No attachment of particles of μm or more was observed at all. In addition,
In the embodiment shown in FIG. 13, the loading and unloading of the glass substrate 40 into and from the local clean space 1 was performed through one opening 4 formed in the partition 3.

2. Rubbing Step The rubbing step is a step of aligning liquid crystal molecules,
It is used in almost all LCD mass production lines.
The rubbing method generally used is to rub the surface of the substrate with an alignment film while rotating a metal cylindrical roller having a cloth on which cotton and nylon fibers are planted adhered. Typical causes of the generation of static electricity in the rubbing step include frictional charging between the rubbing cloth and the substrate surface in the rubbing process, and contact separation charging that occurs when the substrate is peeled off from the table after the rubbing process. In both cases, the capacitance measured on the metal table is large, so the voltage measured on the spot is very low.However, when the substrate is peeled off from the table, the capacitance decreases sharply, and as a result, It generates voltages from 1,000V to tens of thousandsV. At this time, discharge occurs between the wiring on the board surface,
The alignment film is destroyed. The upper limit of the allowable static voltage value of the STN type is several hundred volts or less, whereas the upper limit of the allowable static voltage value of the active matrix LCD represented by the TFT type is 50 volts or less. If not, a serious problem has arisen in that the transistor is destroyed and becomes a fatal defect. Thus, an example in which the present invention is applied in such a rubbing step to prevent static electricity will be described while showing data of charging and failure inspection of a glass substrate and comparing with a conventional technique.

(1) Conventional example In a clean room (23 ° C., 45% RH, class 10)
Then, the glass substrate (3.
(00 mm × 400 mm × 1.1 ^t mm) was carried into the rubbing device from the cassette case, and rubbing was performed.
The charging of the glass substrate occurs at three places: (a) peeling from the robot hand, (b) friction by rubbing, and (c) peeling from the table. When the charging of the glass substrate was measured with a surface voltmeter, strong charging of 10 kV or more occurred at any point. When the glass substrate after the rubbing treatment was inspected, the alignment film and the transistor were broken. This glass substrate was completely defective.

(2) Example of the Present Invention FIG. 14 schematically shows an example in which the local cleaning space 1 of the present invention is applied to the case where a rubbing step is performed. Inside the local cleaning space 1, a cassette case 51 that stores a predetermined number of glass substrates 50 carried through the opening 4 formed in the partition 3 is placed. The glass substrate 50 is taken out one by one from the cassette case 51 by the arm of the transfer robot 52, and the glass substrate 50 is carried into a rubbing device 53 to perform a rubbing process. The processed glass substrate 50 is unloaded by the transfer robot 54 through the opening 5. A plurality of FFUs 6 with built-in HEPA filters are installed on the ceiling of the local cleaning space 1, and the cleaning of the local cleaning space 1 is controlled to a predetermined temperature and humidity (23 ° C., 70% RH) by operating the FFU 6. Air (class 10) is supplied, and the inside of the local clean space 1 is maintained in a rectified state.

In the local cleaning space 1, the transfer robot 52 performs the wet cleaning on the glass substrate 50 (3).
(00 mm × 400 mm × 1.1 ^t mm) is taken out of the cassette case 51 and carried into the rubbing device 53 to perform a rubbing process. In the figure, at (a), (b) and (c), (a) peeling from the robot hand, (b)
The electrification of the glass substrate 50 caused by the friction due to rubbing and (c) peeling from the table was measured by a surface voltmeter. In the embodiment to which the local cleaning space 1 of the present invention was applied, the electrification of the glass substrate 50 was (A), (b),
In each of (c), the voltage was 40 V or less. And
When the glass substrate after the rubbing treatment was inspected, no defect was observed in the alignment film and the transistor, and the glass substrate was a completely good product.

[0067]

According to the present invention, by handling (handling) an insulative article such as a glass substrate in a humidified local clean space, the generation of static electricity generated in the insulative article or the like can be reduced. In addition to the suppression, it is possible to easily and instantly remove the electrostatic charge once generated. According to the present invention, electrostatic discharge (ESD: Elec)
A high-quality glass substrate can be obtained without destruction or deterioration of the element due to Trostidischarge and no adhesion of dust particles due to electrostatic attraction, so that mass production of high-quality LCDs becomes possible.

[Brief description of the drawings]

FIG. 1 is a graph showing the change over time of the surface potential of a glass substrate when a film is in contact with and peeled off (without grounding), showing the results of an experiment for examining the leakage characteristics of charged charges on an LCD glass substrate.

FIG. 2 is a graph showing a change with time in the surface potential of a glass substrate when there is one grounding point.

FIG. 3 is a graph showing an increase in potential decay rate due to an increase in the number of grounding points (80% relative humidity).

FIG. 4 is a graph showing the change over time of the surface potential of a glass substrate when a film is peeled off in a soft X-ray irradiation atmosphere (relative humidity: 40%).

FIG. 5 is a schematic front view of a local cleaning space according to an embodiment of the present invention using a vaporizing humidifier.

FIG. 6 is a plan view of the same.

FIG. 7 is a perspective view of a vaporizing humidifier.

FIG. 8 is a schematic front view of a local cleaning space according to an embodiment in which a water tank is provided at the bottom.

9 is a graph showing measurement results of humidity controllability in the local clean space of FIG. 5 (opening size: fully closed).

FIG. 10 is a graph showing the measurement results of the humidity controllability when the opening size is 500 × 500 mm ² (two locations).

FIG. 11 is a graph showing measurement results of humidity controllability when the opening size is set to 500 × 800 mm ² (two locations).

FIG. 12 is a graph showing the results of measuring the amount of exhaust gas passing through an opening when the suction amount of the exhaust fan is zero.

FIG. 13 is an explanatory diagram of an embodiment in which the local cleaning space of the present invention is applied to a surface inspection line of a glass substrate.

FIG. 14 is an explanatory diagram of an embodiment in which the local cleaning space of the present invention is applied to a rubbing step of a glass substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Local clean space 2 Clean room 3 Partition 4, 5 opening 6 FFU 10 Humidifier 26 Exhaust fan

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-178315 (JP, A) JP-A-3-275150 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F24F 7/007 F24F 7/06

Claims (5)

(57) [Claims] 1. A local cleaning space formed by partitioning the inside of a clean room by using a partition, wherein an opening for carrying in an article into the local cleaning space and / or an article out of the local cleaning space. The partition is provided with an opening to humidify the inside of the local clean space, and exhaust from the local clean space so that the atmospheric pressure in the local clean space is lower than the atmospheric pressure in the clean room outside the local clean space.
Air in the clean room through the opening
A local clean space characterized by comprising: an exhaust means for flowing into the space. 2. The interior of a clean room is partitioned.
A local clean space formed by partitioning the local clean space, and an opening for carrying articles into the local clean space; and / or
Or an opening for taking out goods from the local clean space
Humidifying means installed in the local clean space, and a clean room outside the local clean space
Exhaust from the local clean space so that it is lower than the internal pressure
Air in the clean room through the opening
Exhaust means for flowing in between, the local clean space is a space for processing an LCD substrate
A local clean space characterized by the following. 3. The interior of the clean room is partitioned.
A local clean space formed by partitioning the local clean space, and an opening for carrying articles into the local clean space; and / or
Or an opening for taking out goods from the local clean space
Humidifying means installed in the local clean space, and a clean room outside the local clean space
Exhaust from the local clean space so that it is lower than the internal pressure
Air in the clean room through the opening
Exhaust means for flowing the gas into the space, a processing space is formed in the local clean space, and a station is provided in the processing space.
Air supply means for circulating and supplying air inside the
A local clean space characterized by: 4. The local clean space according to claim 3, wherein the air circulated and supplied into the processing space by the air supply means is rectified. 5. The method according to claim 1, wherein a filter is provided in the air supply means.
The local clean space according to claim 3 or 4, characterized in that it is characterized by: