KR20030095365A - The process for cleaning a glass surface in manufacturing lcd - Google Patents

Abstract

PURPOSE: A method for cleaning an LCD substrate using ozone water is provided to optimize a degree of cleaning without adding chemicals, thereby improving the productivity and reducing the cost for the chemicals. CONSTITUTION: DIW(Deionized Water) is electrolyzed through an electrolyzed water generator(100) to be transferred to an agitator(300). An ozone water generator(200) generates ozone water by generating electric discharge in oxygen and the DIW, and transfers the ozone water to the agitator. The agitator mixes the electrolyzed water with the ozone water, and transfers the mixed ozone electrolyzed water to an ultrasonic wave generator(400). The ultrasonic wave generator activates the ozone electrolyzed water, and transfers the ozone electrolyzed water to an ozone water spray unit(500). The ozone water spray unit sprays the activated ozone electrolyzed water on a substrate of an LCD(Liquid Crystal Display). The ozone water used in the cleaning process is recovered and filtered through a filter(600) to be reused in the ozone water generating process.

Description

Method for cleaning LCD substrate using ozone water {THE PROCESS FOR CLEANING A GLASS SURFACE IN MANUFACTURING LCD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cleaning substrates during LCD manufacturing processes, and more particularly, to a method of cleaning substrates using ozone ionized water.

In general, LCD injects a liquid crystal, which is an intermediate between solid and liquid, between two thin glass plates, and changes the arrangement of liquid crystal molecules by the voltage difference between the electrodes on the upper and lower glass plates. Refers to the used device.

The passive matrix type and the active matrix type are classified according to the driving method. The passive matrix type includes TN (Twisted Nematic) and STN (Super Twisted Nematic), and the active matrix type includes a thin film transistor (TFT).

Recently, as the demand of TFT LCD increases, researches to improve the function of TFT LCD are being conducted. Therefore, since the 1990s, research on TFT LCD has been focused on large area, wide viewing angle, and high opening ratio, and this trend will continue in the future.

The LCD production process is largely classified into a cell process that produces the LCD panel itself and a module process that assembles the finished panel into a finished product.

In the cell process, on the original glass TFT glass and C / F glass are generated by repeating the cleaning, deposition, and etching process. Manufacture. Since the generated TFT and CF patterns are the result of the micro process that forms the core of the LCD, a cleaning process for removing foreign matter particles is required for each detailed step of the cell process.

The spacer is joined while putting the spacer between two pieces of glass completed by the above process. Inject the liquid crystal into the space between them.

Module process is the process of producing the finished TFT panel as one module. That is, the module is completed through the process of LCD driver driver IC and back light attachment.

The cleaning process required between the detailed processes of the LCD manufacturing process is an important process that influences the improvement of the LCD production yield. Currently used cleaning process is LCD Glass manufacturing and C / F process as above. It is used in each step, and it is performed repeatedly 7 to 8 times as a whole.

As the cleaning liquid used in the cleaning process, chemicals called TEM (TetraMethylAmmonium Hydride), which is a type of DIW (Deionized Water) or a surfactant, are generally used.

The main cleaning targets of the chemicals are organic matters such as oils and fats, such as oils and fats, which cause deterioration in adhesion force of thin films and particles, which cause short circuits and short circuit leakage in TFT-LCDs using a-Si. of It is a natural oxide film to damage.

Enough cleaning and removal of these contaminants If this is not done, pattern defects on the array substrate or malfunction of the transistor element frequently occur, which lowers the yield of the array substrate.

Therefore, it is very important to select a cleaning method, a cleaning facility or a cleaning process suitable for each cleaning purpose.

Currently, the cleaning process used in the TFT-LCD manufacturing process relies only on a simple cleaning method using several times using only ultrapure water, compared with semiconductor cleaning.

Therefore, development of cleaning technology suitable for each film quality used in TFT-LCD manufacturing and TFT-LCD There is an urgent need to develop a cleaning technology that can maximize performance.

Conventional cleaning process First, remove particles and metal impurities using chemical, and remain secondly Rinse process using DIW to remove chemicals, and UV process to remove the organic material in the third.

However, the cost of each process is enormous, and in the case of LCDs using low-temperature Poly-Si TFTs, semiconductor level cleaning is required. Therefore, development of an improved cleaning technology is urgently needed.

In addition, in actual process, SiO on the glass substrate₂When applying film formation, applying Poly-Si layer, or after laser heat treatment and lithography Radicals present interfere with the physical and chemical bonds between the thin films and reduce production yields.

Chemical and physical cleaning, which is used to remove this, creates crystallographic bonds and residual ions in the thin film, which degrades the performance It causes a decrease in production yield.

Therefore, the introduction of a wet cleaning method using electrolyzed water (EW), a new cleaning method that is environmentally friendly and does not generate ions, is required.

Due to the recent demand for environmental protection and low manufacturing costs, the reduction of chemical consumption is increasingly It is an important issue. In response to these environmental changes, chemical concentrations are reduced and new compounds are maintained while maintaining the ability to remove contaminants in conventional liquid cleaning processes. Development of cleaning solvents is required.

Therefore, several physical cleanings (Ultrasonic cleaning), wet cleaning and dry cleaning have been proposed since 1990, aiming at adding new functions and lowering the cleaning process cost.

Among these cleaning methods, a chemical called TMAH (Tetra Methyl Ammonium Hydro-oxide) There is a cleaning method to be used, and at present, the chemical is combined with ultrapure water and physical cleaning. Many methods of applying and washing are used.

While the cleaning method has been improved in its cleaning function, the cleaning method, the running cost of the cleaning process, or the cost generated after cleaning due to the problem of using a very large amount of ultrapure water in applying the cleaning method to the entire LCD manufacturing process. Problems such as wastewater treatment remain.

In addition, in the TFT-LCD surface treatment that is currently used, many kinds of chemicals As it is being used, there are always problems such as chemical cost, post-treatment cost, worker safety, and environmental pollution.

That is, due to the large number of chemicals and large amounts of water used in the cleaning process, Since a large amount of wastewater and waste is generated, problems such as cost increase, worker safety problems, and pollution generation occur.

Therefore, there is a strong demand for the development of a new process that does not generate pollutants in view of not generating pollutants at all, rather than treating the generated pollutants.

The United States has already embarked on specific actions to regulate the generation of pollutants, and through a joint research effort between the government and businesses through SEMATECH, It is in a state.

Japan is also actively pursuing joint development projects with the cooperation of the Ministry of Trade and Industry. It is showing.

The domestic industry is also weak, but review the data and data and conduct basic research. Although it is pushing forward, it is heavily dependent on foreign countries due to technical inferiority of materials and equipment companies. At the same time, there is a passive response through process optimization.

Domestic There is almost no development of alternative technology and process improvement technology to alleviate the emission of toxic substances generated in the TFT-LCD manufacturing process.

An object of the present invention is to provide an environmentally friendly cleaning method using little chemicals.

Still another object of the present invention is to provide a cleaning method having high economical efficiency by reducing the cost by not using chemicals and reducing the cost due to the simplification of the process.

Another object of the present invention is to provide a cleaning method that can significantly reduce the amount of ultrapure water by reusing water once used for cleaning.

Still another object of the present invention is to provide an ozone water generator that can be freely used anywhere using a commercial power source.

1 is a structural diagram of the ozone water generator of the present invention.

2 is a cross-sectional view of the ozone water injection device of the present invention.

3 is a view showing a process to which the cleaning process of the present invention can be applied among semiconductor manufacturing processes.

The present invention relates to a method for cleaning an LCD substrate, and more particularly, to a method for cleaning an LCD substrate with ozone ionized water activated using ozone ionized water and ultrasonic waves.

An LCD substrate cleaning method according to the present invention comprises: an ionizing water generating process for generating ionizing water by using an ionizing water generating device; An ozone water generating step of generating ozone water using an ozone water generating device; A stirring step of mixing and stirring the ionizing water and the ozone water to generate ozone ionizing water; An ozone ionization water activating step of activating the ozone ionization water using an ultrasonic generator; A cleaning step of cleaning the LCD substrate using the activated ozone ionizing water; And an ozone water recovery process for recovering the ozone ionized water used in the washing process, filtering and reusing it. It is made, including.

Hereinafter, the present invention will be described in detail for each process with reference to the drawings.

(1) ionizing water generation process

This process is a process of generating the ionizing water by using the ionizing water generating apparatus (100).

The ionized water is electrolyzed using an ion exchange membrane and separated into water ionized with ions of H ⁺ and oxidizing ability and ions of OH ⁻ and reducing ability.

Thus, the ionized water has a very wide range of pH and Oxidation Reduction Potnetial (ORP) without adding trace chemicals or adding chemicals. Therefore, the present invention is to optimize the cleaning degree by using the ionized water, so that the productivity of the LCD manufacturing is improved and environmentally friendly technology.

In addition, the ionized water has a strong cleaning power because the pH and redox power required for each process during LCD cleaning. In addition, the surface tension is small because H ⁺ and OH ^- made by the ionizing water molecules are smaller than those of ordinary water. Therefore, it is easy to penetrate even small micro holes, and can be cleaned up to the finer part than the existing method.

Therefore, the degree of integration of the LCD can be increased and the cleaning effect can be improved.

(2) ozone water generation process

This process is a process of generating ozone water using the ozone water generator 200.

Ozone is usually generated by electric discharge in oxygen. Ozone generators have already been developed and are commercially available. However, the conventional ozone generator has a problem of being expensive and bulky.

A typical example of the conventional ozone generation method is the dielectric barrier discharge method, which is a kind of krona discharge. In other words, dielectric barrier discharge refers to a method in which a dielectric is interposed between electrodes and causes an alternating current discharge. In the dielectric barrier discharge, the dielectric between the electrodes prevents the arc discharge from occurring so that the AC discharge continues.

However, the dielectric faces and facets create new capacitances, which cause new vibrations. Therefore, there is a problem that the plasma generated by the dielectric barrier discharge is not uniform and thus unreliable.

Accordingly, in the present invention, a resistive barrier discharge using a resistive material is used. Resistor barrier discharge is a method of inserting a resistor between electrodes. The resistor not only prevents arc discharge but also reduces unstable vibration during discharge. Thus, the discharge is stabilized and a uniform and stable plasma is generated.

In addition, the resistor barrier discharge has an advantage that can be used to select the direct current or alternating current for convenience.

The present invention can use a commercially available cheap transformer as a power device. For example, a neon ballast with a transformer specification of 15kV, 20kV, or 60kV may be used. The current obtained from the transformer can be rectified and used as a direct current or direct current.

The wide wire mesh electrode forms a stable discharge space and causes a uniform wide discharge.

In addition, most of the power is converted to heat during discharge, and the heat also increases the gas temperature in the discharge zone and the temperature of the barrier between the electrodes. However, the wide wire mesh electrode used in the present invention widens the discharge region, thereby efficiently dissipating heat generated during the discharge process so that the gas temperature is maintained at room temperature.

There are two ways to generate ozone water using the resistor barrier discharge system.

One method is as follows.

As a method of generating ozone in oxygen, a corona discharge generated in oxygen generates a large amount of ozone. The ozone generated in this way is delivered to the gas diffuser in the water through an exhaust pipe attached to the discharger, and ozone and oxygen molecules are released into the water as small bubbles through the diffuser. At this time, ozone molecules are dissolved in water and ozone water is produced.

Another method is as follows.

The discharge is carried out directly on the surface of the water. The ozone water generator that performs this method has a structure in which a high voltage power source is connected to a wire mesh electrode and a resistor is attached below the wire mesh electrode. In the ozone water generator, when oxygen passes between the water surface and the bottom surface of the resistor, corona discharge is generated between the wire mesh electrode through the resistor and the grounded water surface. Oxygen is decomposed and ozone is synthesized by the corona discharge. The ozone generated in this way is dissolved in water and ozone water is produced. At this time, the water beneath the resistor can continue to flow to generate a high concentration of ozone water, it can generate a large amount of ozone water.

The resistive barrier discharge system of the present invention has the advantage that the space can be efficiently used by stacking the discharge structure in multiple layers.

In addition, the ozone water generating device according to the present invention has a strong oxidizing power and sterilizing power because ozone gas is dissolved in water, and is almost harmless to human body because there is almost no ozone gas flowing into the atmosphere. It is also environmentally friendly with no secondary pollutants.

Therefore, by replacing the UV process to remove organic substances adsorbed on the surface of the wafer and impairing the performance of the semiconductor device or LCD substrate by the technology of the present invention, cleaning of various industrial equipment, disinfection, hospital laundry sterilization, residual Pesticide removal can be easily solved with ozone water.

(3) stirring process

This step is a step of mixing the ionized water and ozone water generated by the ionized water generator 100 and the ozone water generator 200 using the stirring device (300).

That is, alkaline water and ozone water generated in the cathode cell 110 of the ionizing water generator 100 are mixed, and acidic water generated in the Anode cell 120 of the ionizing water generator 100 is mixed. Each mixed solution is stirred using the stirring device 300 to generate ozone ionized water for each ionized water.

(4) ozone ionization water activation process

This step is to activate the ozone ionized water using ultrasonic waves.

That is, the ozone ionized water is irradiated with ultrasonic waves generated by magasonic, which is an ultrasonic generator 400, to give an applied vibration to the ozone ionized water. The ozone ionizer with applied vibration has strong cavitation or vibration acceleration and can remove contaminants.

At this time, the frequency of the ultrasonic wave irradiated to activate the synthesis of the fine organic or inorganic matter and ozone water attached to the substrate is adjusted to 20 to 100 Hz. However, it is necessary to be careful because the wavelength of vibration is long, which may cause cleaning stains caused by stationary waves, and damage the thin film pattern by strong cavitation.

(5) cleaning process

In this step, the activated ozone ionizing water is sprayed onto a substrate requiring cleaning to clean contaminants present on the substrate.

That is, the activated ozone ionizing water is sprayed onto the glass surface 700 by using the ozone ionizing water injector 500 to clean the contaminants. At this time, the activated ozone ionized water is injected through the injection nozzle 510 installed in the ozone ionized water injection device 500, the hole of the injection nozzle is preferably about 0.5mm to 3mm in diameter.

In addition, the injection nozzle 510 adjusts the distance between the nozzle end and the glass surface 700 to about 2 to 13 mm, and as shown in FIG. 2, the angle 520 formed between the center line of the injection nozzle and the LCD substrate is 90 degrees. It is preferable to adjust so that it may be from 85 to 85 degrees.

The mixture of alkaline and ozone water in ozone ionizing water replaces chemicals in the particle and metal impurity removal process.

In addition, the mixture of acidic water and ozone water is used to replace the UV process to remove organic substances that are adsorbed on the glass surface during the cleaning process and impair the performance of the LCD.

(6) ozone water recovery process

This process is to recover and filter the ozonized ionized water used to clean the glass surface 700 in the cleaning process, and to reuse it again in the ionized water generation process and ozone water generation process.

The ozone ionized water used once is consumed almost all of the electrolyte and ozone component during the cleaning process, and is similar to the original ultrapure water.

However, the recovered ozone ionized water contains contaminants and various foreign substances generated during the cleaning process and cannot be reused as they are. Therefore, the recovered ozone ionized water is filtered by using the filtration device 600 and then used again in the ionized water generation process and ozone water generation process. In this case, the ionization water generation process and the ozone water generation process use ultrapure water having a very high purity, so that the filtration process includes a filter that can remove fine particles and a deionization process that can also remove ions. I use it.

However, in the case of the present invention, even if the ionized water after the washing process is not reused, the salt is not generated when mixing the waste water (acidic water and alkaline water) generated after washing, so that neutral water is generated. There is a possible advantage.

Therefore, the present invention is a very environmentally friendly technology.

In addition, in the process of the present invention, a predetermined cleaning effect can be obtained by simply activating ozone water and the ultrasonic generator without using the ionizing water using the ionizing water generator.

5 and 6 show the overall LCD main process, the process that can be applied to the ozone ionizing water cleaning method of the present invention in the LCD cleaning process is indicated by hatched.

As can be seen in Figures 5 and 6 it can be seen that the cleaning method according to the present invention can be used efficiently in a very many processes of the LCD production process.

Best Example

The following presents the best embodiment of the present invention.

First, ultrapure water is electrolyzed through the ionizing water generator 100. At this time, the alkaline water and the acidic water are separated through the semipermeable membrane and then transferred to the stirring apparatus 300 through the Cathode cell 110 and the Anode cell 120.

In this case, the ozone water generator 200 generates ozone water by discharging the supplied oxygen and ultrapure water, and transfers the ozone water to the stirring device 300.

The ionized water and the ozone water transferred to the stirring apparatus 300 are mixed and stirred by the stirring apparatus 300. The mixed and stirred ozone ionized water is transferred to the ultrasonic generator 400.

In the ultrasonic generator 400, the frequency of ultrasonic waves is adjusted to 20 to 100 Hz. The ultrasonic wave activates the ozone ionized water. The activated ozone ionized water is sent to the ozone ionized water injector 500.

The activated ozone ionizer sent to the ozone ionizer spraying device 500 is sprayed onto the LCD substrate 700 of the LCD to be cleaned by the sprayer. In this case, it is most preferable that the diameter of the injection nozzle 510 of the injection device is 0.5 mm to 3 mm, and the injection nozzle 510 has a gap between the nozzle end and the glass surface 700 of about 2 mm to 13 mm. It is most preferably installed to be, and as shown in Figure 4 it is preferable to adjust the angle 520 formed between the center line of the injection nozzle and the LCD substrate to 90 ° to 85 °.

The ozone ionized water used in the washing process is recovered, filtered using the filtration device 600, and then supplied to the ionized water generator 100 and the ozone water generator 200 for reuse.

The ozone ionized water according to the present invention is a washing water produced by electrolyzing ultra pure water (DIW, Deionized Water), which uses almost no chemicals and uses less pure water than conventional methods.

Therefore, the present invention uses the washing water having a very wide range of pH and ORP (Oxidation Reduction Potnetial) without the addition of chemicals, so that the productivity can be improved by optimizing the cleaning degree, and the effect of performing environmentally friendly cleaning can be achieved. have.

In addition, according to the present invention Not only can it reduce the cost of chemicals, Significant reductions can also result in economic cost savings.

In addition, the cleaning method according to the present invention can give the washing water by applying the pH and the redox power required in each process during the LCD cleaning. In particular, since H ⁺ and OH ^- made by molecules of ionized water (EW) are smaller than ordinary water, penetration is easy even in small holes having a small surface tension. Therefore, it is possible to clean even the finer part than the prior art, and to increase the degree of integration of the LCD substrate.

In addition, the washing method according to the present invention can reduce the number of washing steps repeated several times, thereby simplifying the process and suppressing the amount of ultrapure water used.

In addition, the washing method according to the present invention can be used by recirculating the water used for washing can significantly reduce the amount of ultrapure water used. Therefore, by reducing the occurrence of environmental pollution in the LCD production process, it is possible to fundamentally respond to environmental regulations in developed countries by solving industrial environmental problems.

In addition, the ozone water generator according to the present invention has a great advantage that can be freely used anywhere using a commercial power source as a low-cost, high-efficiency equipment. Therefore, it is economical, so it can be widely used by small farmers and small and medium-sized enterprises without any big economic burden.

Claims (10)

Ozone water generation process of dissolving ozone generated in ozone water generating device in ultrapure water (DIW) to generate ozone water; An ozone water activation step of activating the ozone water by using an ultrasonic generator; And A cleaning step of cleaning the LCD substrate by spraying the activated ozone water onto the LCD substrate using an ozone water injection device; And An ozone water recovery / filtration process for recovering the ozone water used in the washing process, filtering and reusing it in the ozone water generating process; of LCD substrate cleaning method using ozone water, characterized in that it comprises. An ionizing water generating step of generating an ionizing water by electrolyzing ultra pure water (DIW) using an ionizing water generating device; Ozone water generation process in which ozone water is generated using an ozone water generator; A stirring step of mixing and stirring the ionized water and the ozone water to generate ozone ionized water; An ozone ionization water activating step of activating the ozone ionization water using an ultrasonic generator; And A cleaning step of cleaning the LCD substrate by spraying the activated ozone ionizer onto the LCD substrate using an ozone ionizer spray device; LCD substrate cleaning method using an ozone ionized water, characterized in that it comprises a. The method of claim 2, An ozone water recovery / filtration process for recovering the ozonized ionized water used in the washing process, filtering and reused in the ionized water generating process; of LCD substrate cleaning method using an ozone ionized water, characterized in that it further comprises. According to claim 2, The ozone ionizing water injection device, LCD substrate cleaning method using an ozone ionizer, characterized in that the diameter of the injection nozzle hole is 0.5 mm to 3 mm. The method of claim 2, And the ozone ionizing water spraying device is installed such that a distance between an injection nozzle end of the ozone ionizing water spraying device and the LCD substrate is between 2 mm and 13 mm. The method of claim 3, And cleaning the ozone ionizing water injector so that an angle formed between the center line of the spray nozzle and the LCD substrate is 90 ° to 85 °. The method of claim 2, The ionizing water is an alkaline water containing OH ^- ions or acidic water containing H ⁺ ions, the ozone ionizing water is an alkaline ozone ionizing water or an acidic ozone ionizing water, LCD substrate cleaning method using an ozone ionizing water, characterized in that . The method of claim 7, wherein The alkaline ozone ionized water is an LCD substrate cleaning method using ozone ionized water, characterized in that to remove particles or metal impurities present in the LCD substrate. The method of claim 7, wherein The acidic ozone ionizing water is adsorbed on the surface of glass (glass) LCD substrate cleaning method using an ozone ionizing water, characterized in that for replacing the UV process for removing organic substances that inhibit the performance of the LCD. The ionizer generator of claim 2, LCD substrate cleaning method using an ozone ionizer, characterized in that the variable resistor is installed.