JP3507590B2 - Wet processing method and processing apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet treatment method and treatment apparatus for an object to be treated such as a glass substrate for a liquid crystal display which is required to have an extremely clean surface.

[0002]

2. Description of the Related Art For the wet treatment of an object to be treated such as an electronic component which is required to obtain an extremely clean surface, LS
I Wet processing of a silicon wafer used for manufacturing will be described below as an example.

In the LSI manufacturing process, an insulating film such as SiO ₂ is formed on a silicon wafer, a predetermined pattern of windows is opened in the insulating film to expose metallic silicon under the insulating film, and then wet processing is performed. In response to the,
The element is formed by repeating the step of introducing a p ⁻ type or n ⁻ type element and embedding a metal wiring such as Al.

During the process of introducing the p ^- type or n ^- type element or the step of burying the metal wiring, foreign matter such as fine particles, metal, organic matter, etc. are exposed on the exposed metal silicon surface.
If impurities such as a natural oxide film are attached, defective element characteristics such as a metal-silicon wiring failure and an increase in contact resistance occur. Therefore, in the LSI manufacturing process, the surface wet treatment step is a very important step for manufacturing a high-performance element, and it is necessary to remove the adhered impurities on the wafer surface as much as possible.

Conventionally, the wet processing of a semiconductor wafer has been performed by using, for example, the following technique. That is, a mixture of sulfuric acid / hydrogen peroxide water mixed solution, hydrochloric acid / hydrogen peroxide water mixed solution, ammonia / hydrogen peroxide water mixed solution, hydrofluoric acid solution, solution such as ammonium fluoride solution, and ultrapure water are used in combination,
Without compromising the flatness of the semiconductor surface at the atomic level,
The step of removing organic substances, fine particles, metals, and natural oxides adhering to the semiconductor surface, for example, the steps shown below as examples.

(1) Sulfuric acid / hydrogen peroxide cleaning (sulfuric acid: hydrogen peroxide solution = 4: 1, volume ratio) 130 ° C. 10 minutes (2) Ultrapure water cleaning 10 minutes (3) Hydrofluoric acid cleaning (hydrofluoric acid 5%) 1 minute (4) Ultrapure water cleaning 10 minutes (5) Ammonia hydrogen peroxide cleaning (ammonia water: hydrogen peroxide solution: ultrapure water = 0.05 : 1: 5, volume ratio) 80 ° C 10 minutes (6) Ultrapure water cleaning 10 minutes (7) Hydrofluoric acid cleaning (hydrofluoric acid 0.5%) 1 minute (8) Ultrapure water cleaning 10 minutes (9) Hydrochloric acid hydrogen peroxide cleaning (hydrochloric acid: hydrogen peroxide solution: Ultrapure water = 1: 1: 6, volume ratio) 80 ° C. 10 minutes (10) Ultrapure water cleaning 10 minutes (11) Hydrofluoric acid cleaning (hydrofluoric acid 0.5%) 1 minute (12) Ultrapure water cleaning 10 Min (13) Spin Drying or IPA (Isopropyl Alcohol) Vapor Drying Here, the multiple stages of the wet treatment described as an example above. The role of each wet processing step, which is divided into, will be described. The (1) cleaning with sulfuric acid / hydrogen peroxide is a process mainly for removing organic substances adhering to the surface. Further, the step (5) of cleaning with ammonia hydrogen peroxide is mainly a step for removing fine particles adhering to the surface, and the step (9) of cleaning with hydrochloric acid hydrogen peroxide is mainly for removing metallic impurities adhering to the surface. Process of
The hydrofluoric acid cleaning described in (3), (7), and (11) is a process for removing the natural oxide film on the surface.

Further, the wet treatment of an object to be treated such as an electronic component required to obtain an extremely clean surface will be described below by taking the wet treatment of a glass substrate used for manufacturing a liquid crystal display device as an example.

In the liquid crystal display manufacturing process, a gate metal wiring such as Cr is formed on a glass substrate, a gate insulating film such as silicon nitride is further formed, and an amorphous silicon i layer and an amorphous silicon n ⁺ layer are further formed. Further, metal wiring such as Al / Cr is formed. After that, a window having a predetermined pattern is opened in the metal wiring and the amorphous silicon n ⁺ layer to expose the amorphous silicon i layer, and then an interlayer insulating film such as silicon nitride is repeatedly formed to form a liquid crystal driving element. To do.

At the interface between the gate metal wiring and the gate insulating film and the interface between the gate insulating film and the amorphous silicon i layer,
For example, when foreign matter such as fine particles, impurities such as metal, organic matter, and natural oxide film are attached, defective element characteristics such as wiring failure of metal-silicon and increase of contact resistance occur.

Therefore, in the liquid crystal display device manufacturing process, the surface wet treatment step after thin film formation is a very important step for manufacturing a high-performance element, and it is necessary to remove adhered impurities on the surface as much as possible. There is.

Conventionally, the wet treatment of a glass substrate for manufacturing a liquid crystal display device has been performed by using, for example, the following technique.

That is, by using a combination of an organic solvent, a water-soluble surfactant solution, and ultrapure water, a step of removing mainly organic substances and fine particles adhering to the substrate surface, for example, by the steps shown below as an example: Done.

(1) Ultrapure water cleaning / immersion cleaning / 5 minutes (2) Surfactant cleaning / ultrasonic (40 kHz) / immersion cleaning / 5 minutes (3) Ultrapure water cleaning / ultrasonic (40 kHz) / immersion Washing/
5 minutes (4) Ultrapure water cleaning / ultrasonic wave (950 kHz) / immersion cleaning / 5 minutes (5) Drying / IPA vapor drying In the above, ultrapure water is generally a primary pure water treatment system. High-purity water (secondary pure water) produced by a pure water producing apparatus provided with a secondary pure water treatment system next to the second pure water treatment system is not always defined by the treatment procedure, and the object of the present invention is The water for wet treatment (high-purity water) for electronic parts and the like which is required to obtain an extremely clean surface such as a semiconductor substrate is sufficient.

As a method for bringing the surface of a semiconductor wafer substrate or a glass substrate for a liquid crystal display device into contact with wet treatment chemicals or ultrapure water as described above, a chemical generally called a batch cleaning method (or Ultrapure water)
A method of immersing a plurality of substrates together in a wet processing tank in which a plurality of substrates are stored is often used. In this batch cleaning method, the chemicals in the wet treatment tank are circulated and filtered in order to prevent contamination of the chemicals during the wet treatment. In addition, rinse (rinse)
As for the method, when rinsing with ultrapure water, overflow rinse is used to supply ultrapure water from the bottom of the tank to overflow it from the top of the tank. Some ideas such as quick dump rinses have been made.

Recently, in addition to the batch cleaning method,
A method of showering chemicals or ultrapure water on the substrate surface,
A so-called single-wafer processing method such as a method in which a substrate is rotated at a high speed and a chemical treatment or ultrapure water is applied to the center of the substrate to perform a wet processing is also used. The main purpose of each wet treatment step is as described above, but each wet treatment solution often has a contaminant removal ability other than the main purpose. For example, the sulfuric acid hydrogen peroxide solution of (1) above. Has a strong ability to remove metal deposits in addition to removing organic deposits.
In addition to the above-described exemplary wet treatment system, a method is also used in which one wet treatment liquid is used to remove a plurality of contaminants.

By the way, the rinsing treatment with ultrapure water, which is carried out after the chemical substance removing step in the above-mentioned wet treatment method, is for rinsing the chemical substance remaining on the substrate surface. For this rinse water, it is usual to use ultrapure water produced by an ultrapure water producing apparatus as rinse water. This is because the contaminants may adhere to the substrate surface again after the step of removing the deposits by chemicals, that is, after the substrate surface is already in a clean state with no attached impurities, and the significance of the wet treatment is lost. Because it will be seen. Therefore, as the rinse water for removing chemicals, high-purity ultrapure water, that is, high-purity water from which fine particles, colloidal substances, organic substances, metals, anions, dissolved oxygen, etc. are removed to an extremely low concentration is used. It is being done.

High-purity pure water called ultrapure water is conventionally manufactured by the following method.

That is, a primary pure water treatment system such as a coagulating sedimentation device for raw water, a sand filtration device, an activated carbon filtration device, a reverse osmosis membrane device, a two-bed three-column ion exchange device, a mixed-bed ion exchange device, and a precision filter. Is produced by an ultrapure water production system in which the pure water is further treated in a secondary pure water treatment system immediately before the point of use where the primary pure water is obtained by treating the pure water after treatment with the above-mentioned apparatus. ing.

The ultrapure water producing apparatus as described above is essentially 1
The secondary pure water is stored in the primary pure water tank and sequentially subjected to secondary treatment using an ultraviolet irradiation device, a mixed bed polisher, a membrane treatment device such as an ultrafiltration membrane device or a reverse osmosis membrane device, The ultrapure water (secondary pure water) suitable for the wet treatment of the object to be treated is obtained by removing as much as possible fine particles, colloidal substances, organic substances, metals, anions and the like remaining in water. In addition,
The ultrapure water, which is the permeated water of the membrane treatment device of the secondary pure water treatment system, is generally branched from the middle of the circulation line to the point of use for water supply, and the remaining ultrapure water is supplied to this circulation line. Normally, the water is returned to the primary pure water tank through the return pipe (return pipe), and the amount of water returned to the primary pure water tank through the return pipe is usually the amount of water sent from the membrane treatment device. It is often about 10 to 30%. In the current state of the art, the LS of the submicron design rule
The ultrapure water produced by a general ultrapure water production apparatus for producing I has, for example, the water quality shown in Table 1 below. If such ultrapure water quality is achieved, It is said that contaminants derived from ultrapure water will not adhere to the surface during the rinse step with pure water.

[0020]

[Table 1]

However, the above conventional technique has the following problems. Price competition in the manufacturing field of electronic parts has become severe,
Manufacturing lower cost and higher performance products has become an important issue. In particular, the ratio of the wet processing steps in the LSI manufacturing step and the liquid crystal manufacturing step is large, and there is a strong demand for cost reduction of the wet processing steps while further improving the performance of products. From the technical and economic viewpoints, the following problems in the above-mentioned conventional art are pointed out.

That is, in the case of cleaning the surface of a silicon substrate according to the above conventional technique, most of the solution is still used at the composition and concentration used since the 1970s or before.

For example, since the hydrochloric acid-hydrogen peroxide cleaning solution used to remove adhered metal impurities is a mixed solution of halogen acid and an oxidizing agent, chemical species other than hydrochloric acid and hydrogen peroxide, which are the raw materials, are generated in the solution by the reaction. However, the cleaning effect of these individual chemical species has not been revealed. Since it is not possible to scientifically optimize the composition / ratio, it is the actual situation to rely on the preceding example to add a margin and wash with chemicals that use hydrochloric acid and hydrogen peroxide at concentrations higher than necessary.

As a result, not only is the cost of purchasing the used chemicals wasteful, but also the amount of ultrapure water used as rinsing water after cleaning with a chemical of unnecessarily high concentration becomes unnecessarily large,
Increase ultrapure water production costs. An increase in the amount of chemicals used leads to an increase in the amount of rinsing water, raising the cost of wastewater treatment.

Further, the above-mentioned conventional liquid crystal device has a much smaller degree of integration of elements than an LSI, and requirements for surface impurity control and surface flatness for preventing deterioration of device characteristics are far less strict than those for an LSI process. Therefore, in the case of cleaning the surface of the glass substrate for liquid crystal according to the above-mentioned conventional technique, it is not as complicated as the LSI process and the kind and amount of chemicals used are very small. However, in recent years, in order to develop a higher performance liquid crystal display device, it is necessary to control surface impurities and surface flatness to the same level or more as in the LSI process. On the other hand, it is necessary to fully consider the manufacturing cost reduction and wastewater treatment measures as in the LSI process.

As a technique for improving the cleaning effect by reducing the kinds and amounts of chemicals used, there is a technique described in JP-A-6-260480. In this technique, H ⁺ ion water or OH ⁻ ion water generated by electrolyzing water is constantly supplied to the object to be cleaned, etched, or post-treated.

However, even if this technique is used, the surface cleanliness required in the next-generation liquid crystal display device manufacturing process cannot be satisfied.

[0028]

SUMMARY OF THE INVENTION The present invention uses a minimum amount of chemicals when cleaning an object to be processed such as an electronic component which is required to have an extremely clean surface such as a substrate for a liquid crystal display device. It is an object of the present invention to provide a wet processing method and a processing apparatus capable of further increasing the surface cleanliness compared to the conventional method with a small amount and a minimum number of steps.

[0029]

The wet treatment method of the present invention uses an anode water or a cathode water obtained by electrolyzing an object to be treated by introducing pure water or ultrapure water into a predetermined electrolyzer. A method of wet treatment, in which a predetermined electrolyte is used
Is added to the anode water, or a predetermined electrolyte is added to the cathode water.
While adding water , irradiate ultrasonic waves of 30kHz or more
A feature is that wet processing is performed.

The wet treatment apparatus of the present invention comprises an electrolyzer for electrolyzing water, an introducing pipe system for introducing water into the electrolyzer, and an anode chamber formed in the electrolyzer via a diaphragm. And an electrode pair of an anode electrode and a cathode electrode provided in each of the cathode chamber, a DC power supply for supplying a DC current to the electrode pair, and an anode water and a cathode water obtained by the electrolyzer separately. A lead-out pipe system that can be taken out, a means for adding an electrolyte to the anode water and / or the cathode water obtained by the electrolyzer, and 30 kHz connected downstream of the lead-out pipe system
An ultrasonic wave irradiation unit capable of irradiating the above ultrasonic waves, and a wet processing unit for wet-processing an object to be processed while irradiating the anode water and / or the cathode water with ultrasonic waves are provided. Is characterized by.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of the present invention will be described below along with its operation.

(Claim 1) The invention according to claim 1 is a method in which pure water or ultrapure water is introduced into a predetermined electrolyzer and electrolysis is performed to perform wet treatment using anode water or cathode water. The wet treatment is performed at 30 kHz after adding a predetermined electrolyte to the anode water or the cathode water.
Since it is performed while irradiating the above ultrasonic waves, the amount of chemicals and pure water used and the drainage load from the cleaning process are dramatically reduced. Further, for example, in the surface wet treatment process for a glass substrate for a liquid crystal display device or the like, the treatment effect can be improved much more than in the conventional technique, and therefore, a large amount of chemicals such as the conventional semiconductor surface wet treatment process is required. It is not necessary to use it, and it is possible to reduce the amount of pure water used. In particular, since the electrolyte is added after electrolysis, it is possible to prevent the deterioration of the electrode due to the electrolyte. That is, when an electrolyte is added before electrolysis, the electrolyte causes deterioration of the electrode, and some products are generated with the deterioration, which is considered to cause deterioration of the quality of electrolytic anode water or cathode water. In the invention, such addition can be prevented because the addition of the electrolyte is after the electrolysis. An electrolyte is added to the anode water and cathode water obtained by the electrolyzer, and when the electrolyte is added before the introduction of the electrolyzer, there is no deterioration of the anode electrode caused by the electrolyte and the cleaning effect is excellent. There is.

Further, for example, for the purpose of removing fine particles on the surface of a semiconductor thin film in a liquid crystal display device, if wet treatment is performed while ultrasonically irradiating electrolytic cathode water instead of ammonia hydrogen peroxide, the nitrogen load on the waste water treatment device is reduced. It can be significantly reduced, the wastewater treatment equipment can be downsized, and the wastewater treatment cost can be reduced. Also, for the purpose of removing metallic impurities, if the wet treatment is performed while ultrasonically irradiating the electrolytic anode water instead of chlorine hydrogen peroxide water, the chloride ion load on the wastewater treatment equipment can be significantly reduced, and similarly the wastewater treatment can be performed. Miniaturization of equipment,
Wastewater treatment costs can be reduced.

For the purpose of removing fine particles on the surface of the glass substrate for a liquid crystal display device, a wet treatment may be performed while irradiating the electrolytic cathode water with ultrasonic waves instead of the surfactant brush cleaning and the ultrapure water ultrasonic cleaning. At least, the effect of removing fine particles can be enhanced without increasing the load on the wastewater treatment device. Further, in the conventional glass substrate surface wet treatment process for liquid crystal display devices, there was no particular process for the purpose of removing metal impurities, but if the wet treatment is performed while irradiating the electrolytic anode water with ultrasonic waves, at least the load on the wastewater treatment device will be reduced. The metal removal effect can be enhanced without increasing the value.

Examples of the object to be cleaned in the present invention include various materials and parts used in the field of manufacturing electronic parts, and specifically, semiconductor wafers (silicon wafers, compounds, etc.). Semiconductor wafer), a substrate on which a semiconductor thin film is formed, a thin film magnetic substrate,
Substrate materials such as a superconductor substrate, a liquid crystal display device substrate (eg, a substrate on which a glass substrate, a conductive thin film, an insulating thin film, a semiconductor thin film, etc. are formed), electronic components such as a memory device, a CPU, a sensor device, etc. Examples include finished products and semi-finished products, or metal chambers for various film forming apparatuses, valves, pipes, quartz reaction tubes, cleaning tanks, film forming apparatuses, parts for manufacturing apparatuses such as substrate carriers, and the like.

The washing method is not particularly limited,
For example, any known method such as a batch cleaning method, a flow cleaning method, a showering method, and a single wafer cleaning method can be adopted. In particular, by combining ultrasonic waves in the megahertz band with electrolytic ionized water, the effect of removing submicron-sized particles becomes extremely high.

If the frequency is less than 30 kHz, the cleaning effect is extremely deteriorated, so that the frequency of ultrasonic waves must be 30 kHz or higher.

It should be noted that 1 MHz to 3 MHz is preferable for removing small particles having a size of 1 μm or less.

Further, 30 kHz to 1 MHz is preferable for removing particles having a relatively large particle size of 1 μm or more.

Further, since the metal adhered to the solid surface is often adhered as fine particles, 1 MHz to 3 MHz
Is preferable for removing the metal fine particles.

In order to remove organic substances such as resist or adsorbed organic substances adhering to the solid surface, 30 kHz to
1 MHz is preferred.

In the cleaning process, while changing the frequency, for example, gradually increasing the frequency from 30 kHz to 3 MHz, or from 3 MHz to 30 kHz.
It is preferable to perform cleaning while gradually lowering the frequency.

In the invention according to claim 1, in comparison with the above-mentioned technology (technology described in JP-A-6-260480), which is proposed as a technology in which the kind and amount of chemicals used are reduced and the cleaning effect is improved. Even in this case, a higher cleaning effect can be obtained, the amount of ultrapure water used and the amount of chemicals used can be further reduced, and the amount of waste water or waste chemicals can be reduced. Further, it has a high oxidation potential and is excellent in the ability to remove Ce metal that is difficult to remove.

(Claim 2) The present invention is capable of cleaning the entire surface even in a large area substrate, and is therefore particularly effective when applied to a liquid crystal display substrate. Further, the present invention can be applied without depending on the conductivity of the substrate and does not cause electrostatic charging. Therefore, it can be suitably applied to a liquid crystal display device substrate in which an insulating film and a conductive film are mixed. Further, the present invention is
Since it has an excellent ability to remove Ce, it is particularly suitably used for cleaning after etching the Cr film using a Ce compound as an etching solution.

(Claim 3) In the invention according to claim 3, the treatment is carried out in a state where the material to be treated is immersed in anode water or cathode water.

The number of treatments per unit time can be increased by immersing a large number of treatment objects at once. Further, it is possible to enhance the effect of removing the contamination of the object having poor wettability.

It is preferable that the surface of the object to be processed is vertical and the ultrasonic wave is applied from below in order to further enhance the cleaning effect.

(Claim 4) In the invention according to claim 4, the anode water or the cathode water is continuously jetted or dropped from a predetermined nozzle toward the object to be treated. In this method, the object to be treated is always washed with a fresh cleaning liquid, so that recontamination is extremely small and the object to be treated can be brought into a highly cleaned state.

(Claims 5 and 6) In the invention according to Claim 5, the liquid introduced into the electrolyzer is at least one of an ion exchange device, a membrane treatment device and a distillation device. Pure water or ultrapure water obtained by the production apparatus or ultrapure water production apparatus, or an aqueous solution of an electrolyte obtained by adding a predetermined electrolyte to the pure water or ultrapure water, so that anode water or cathode water with extremely few impurities Obtained,
By irradiating this with ultrasonic waves and treating the object to be treated, the object to be treated can be made in an extremely highly clean state.

In particular, when an electrolyzer of water composed of three intermediate chambers divided by a pair of diaphragms between the anode chamber and the cathode chamber is used, the effect is remarkably improved (claim 6). ).

(Claim 7) Since the diaphragm that separates the anode chamber and / or the cathode chamber from the intermediate chamber is an ion-exchange membrane that is a conductive membrane, the electrical resistance between the anode electrode and the cathode electrode can be reduced. It is possible to obtain electrolytic ionized water at a low voltage.

(Claim 8) Since the intermediate chamber is filled with the conductive solid electrolyte, the electric resistance between the anode electrode and the cathode electrode can be reduced, and electrolytic ion water can be obtained at a low voltage.

(Claim 9) With such a device configuration, the anode water and the electrolyte capable of stably controlling the ionic species, the ion concentration, the redox potential, and the PH (hydrogen ion concentration) with extremely few unnecessary impurities. It is possible to create a mixed solution of the above and a mixed solution of the cathode water and the electrolyte, and to irradiate the anode water and the cathode water with ultrasonic waves for processing, and thus it is possible to obtain a high particle removal property or a high metal content. Shows removability.

(Claim 10) Since the electrolyzer of water is composed of the three chambers of the intermediate chamber divided by the pair of diaphragms between the anode chamber and the cathode chamber, the anode water or the cathode water containing extremely few impurities. Is obtained, and the object to be processed can be treated in an extremely highly clean state by irradiating it with ultrasonic waves.

(Claim 10) Since the electrolyzer of water is composed of the three chambers of the intermediate chamber divided by the pair of diaphragms between the anode chamber and the cathode chamber, the anode water or the cathode water containing very few impurities. Is obtained, and the object to be processed can be treated in an extremely highly clean state by irradiating it with ultrasonic waves.

(Claim 11) Since the diaphragm that separates the anode chamber and / or the cathode chamber and the intermediate chamber is an ion-exchange membrane that is a conductive film, the electrical resistance between the anode electrode and the cathode electrode can be reduced. It is possible to obtain electrolytic ionized water at a low voltage.

(Claim 12) Since the intermediate chamber is filled with the conductive solid electrolyte, the electric resistance between the anode electrode and the cathode electrode can be reduced, and electrolytic ionized water can be obtained at a low voltage.

[0058]

[0059] By degassing thoroughly (claims 1-3) dissolved gas, by which can be transmitted effectively to the treatment object of the ultrasonic wave irradiation,
It is possible to remove organic substances and pollutants with lower energy. If not degassed, the dissolved gas is vaporized by ultrasonic waves and bubbles are generated. When bubbles are generated, the bubbles act as a cushion, and the irradiated ultrasonic waves do not work effectively on the object to be processed. By degassing to 10 ppm, such a problem can be prevented.

[0060]

EXAMPLES The present invention will be described below based on examples. Naturally, the scope of the present invention is not limited to the following examples.

(Embodiment 1) FIG. 1 shows a wet processing apparatus for electronic parts and the like according to this embodiment.

This apparatus comprises an electrolyzer 102 for electrolyzing water, an introducing pipe system 101 for introducing water into the electrolyzer 102, and an anode chamber 103 formed in the electrolyzer 102 via a diaphragm 114. And an electrode pair of an anode electrode 104 and a cathode electrode 107 provided in each of the cathode chambers 106, and electrode pairs 104 and 107.
DC power supply 113 for supplying a DC current to the outlet, and derivation piping systems 105 and 108 capable of separately taking out the anode water and the cathode water obtained in the electrolyzer 102, respectively.
And means 130, 131 for adding an electrolyte to the anode water and the cathode water obtained in the electrolyzer 102,
It is connected to the downstream of the lead-out piping systems 105 and 108, and the anode water 115 and the cathode water 116 are separately separated by 30 k.
Ultrasonic wave irradiating means 109, 111 capable of continuously irradiating ultrasonic waves of Hz or higher, and for wet-treating an object with a treatment liquid obtained by irradiating the anode water and the cathode water with ultrasonic waves. A wet treatment unit and a measuring unit for measuring the ultrasonic irradiation intensity, for controlling the ionic species in the treatment liquid, the ion concentration and the redox potential by adjusting the direct current intensity and the ultrasonic irradiation intensity. It has a control system.

Reference numerals 110 and 112 are objects to be processed.
The wet processing apparatus shown in this embodiment is of a type that performs wet processing by immersing an object to be processed in a liquid.

A glass substrate for a liquid crystal display device was wet-processed by using the wet-process device shown in FIG. The details will be described below together with a comparative example.

An amorphous silicon i-layer was formed on the surface of a glass substrate for a liquid crystal display device, and copper was contaminated on the amorphous silicon i-layer by the contamination method shown in Table 2.

[0066]

[Table 2]

This substrate was subjected to wet treatment by each wet treatment method shown in Table 3. Ultrapure water, hydrochloric acid / hydrogen peroxide solution, sulfuric acid / hydrogen peroxide solution, hydrofluoric acid / hydrogen peroxide solution, electrolytic anode water (pH 2), ultrapure water sonicated water, electrolytic pre-added electrolytic anodic water sonicated water, Electrolyte anode water after electrolyte addition and electrolyte anode water after electrolyte addition were treated with ultrasonic waves.

In Table 3, is a comparative example and is an example.

The electrolytic anode water (pH 2) used in the wet treatment method shown in Table 3 was produced by using the wet treatment apparatus shown in FIG.

FIG. 3 mainly shows the part of the electrolyzer of the wet processing apparatus. The electrolyzer 301 includes an anode chamber 302 having an anode electrode 305, a cathode chamber 304 having a cathode electrode 306, and a pair of diaphragms 30 between the anode chamber 302 and the cathode chamber 304.
It is composed of three chambers, an intermediate chamber 303 divided by 7. The three chambers 302, 303 of the electrolyzer 301,
Introduction piping system 309 (31 for introducing raw water into 304 respectively)
0,311,312) and these three chambers 302,303,
Derivation piping systems 315 and 3 for deriving the processing liquid from 304, respectively.
16 and 317.

In this example, the anode chamber 302 and / or
Alternatively, the diaphragm 307 that separates the cathode chamber 304 and the intermediate chamber 303 is an ion exchange membrane, and the intermediate chamber 303 is filled with a solid electrolyte.

That is, first, ultrapure water is introduced into the piping 309,
Anode chamber 302 via 310, 311 and 312, intermediate chamber 3 filled with a solid electrolyte (ion exchange resin)
03, introduced into the cathode chamber 304 and circulated. that time,
Introducing pipes 310, 3 from the electrolyte adding devices 313, 314
12, HCl and NH ₄ OH were continuously injected respectively in the introduction pipes, pH was 2 in the anode chamber and pH was in the cathode chamber.
The current is adjusted to 8 and a current is directly applied to the electrodes 305 and 306 to continuously generate an electrolysis reaction, and electrolysis anode water (pH 2) and electrolysis cathode water (pH 8) are continuously produced.
Got Then, regarding 130 and 131, the electrolyte was added.

Table 3 also shows the results of the wet treatment.

[0074]

[Table 3]

From the results of the wet treatment shown in Table 3, electrolysis was performed.
It was found that the anode water ultrasonic treated water has a high copper removal effect and the treatment of waste water of the treatment liquid is easy, but when electrolytically obtained anode water obtained by electrolysis after adding hydrochloric acid () is also used. It was found that almost the same cleaning was obtained when the electrolytic anode water obtained by electrolyzing ultrapure water and hydrochloric acid was added ().

In the actual liquid crystal display device manufacturing process, hydrochloric acid hydrogen peroxide solution, sulfuric acid hydrogen peroxide solution,
The hydrofluoric acid / hydrogen peroxide solution cannot be used because of the problems shown in the remarks column of Table 3.

Therefore, only electrolytic anode water and ultrasonically treated water (, (Example)) can be used as a treatment method having a high copper removing effect in an actual process.

(Example 2) An amorphous silicon i layer was formed on the surface of a glass substrate for a liquid crystal display device, and the substrate on which the silica (SiO ₂ ) particles were contaminated on the amorphous silicon i layer was treated with ultrapure water or ammonia gas. As a result of single-wafer treatment with hydrogen oxide solution, electrolytic cathode water (pH 8), ultrapure water ultrasonic treatment water, electrolytic cathode water ultrasonic treatment water, electrolytic cathode water ultrasonic treatment water has the effect of removing particles only electrolytic cathode water Or
It was found that the ultrasonic treatment water of ultrapure water and the effect obtained by continuous treatment of these two treatments were extremely higher than those expected and the treatment of wastewater of the treatment liquid was easy.

The electrolytic cathode water (pH 8) used in the wet treatment method shown in Table 5 was produced by the following method using the electrolyzer shown in FIG.

That is, first, ultrapure water is introduced into the piping 309,
It was introduced and circulated through the anode chamber 302, the intermediate chamber 303, and the cathode chamber 304 via 310, 311, and 312. At that time, from the electrolyte addition devices 313 and 314 to the introduction pipe 31
0, 312, HCl and NH ₄ respectively in the introduction pipe.
Continuously injecting OH, adjusting the pH to 2 in the anode chamber and adjusting the pH to 8 in the cathode chamber, and applying a direct current to the electrodes 305 and 306 to continuously generate an electrolysis reaction,
Electrolytic anode water (pH 2) and electrolytic cathode water (pH 8) were continuously obtained.

Further, the wet treatment apparatus shown in FIGS. 1 and 5 is used to carry out the same method as described above (however, the electrolyte addition is performed from the electrolyte addition apparatuses 130 and 131 to the introduction pipe 31).
5, 317) to obtain electrolytic anode water (pH
2), electrolytic cathode water (pH 8) and electrolytic cathode water (pH 6.8) were irradiated with ultrasonic waves, or the surface of the object to be treated was processed through a process without ultrasonic waves.

[0082]

[Table 4]

[0083]

[Table 5] Wet processing results In Table 5, is an example and the others (-) are comparative examples. Among the comparative examples, ~ is a comparative example in which ultrasonic irradiation is not performed, and, is a comparative example in which ultrasonic irradiation is performed but chemicals and the like are different. Further, is a comparative example in which an electrolyte was added before electrolysis.

As can be seen from Table 5, the removal efficiency is better when the ultrasonic wave is irradiated than when the ultrasonic wave is not irradiated. However, when viewed in terms of the absolute number of remaining particles, 300 particles / 100 cm
It is not possible to reduce the number of survivors from level ² (see ,,). However, it is possible to reduce the remaining number from the level of 100/100 cm ² only when electrolyzed water is used. In particular, adding ammonia,
It can be seen that when pH is set to (8), the achieved cleanliness is significantly improved. It was also found that even when the electrolyte was added after being electrolyzed, the same cleaning effect as in the case where the electrolyte was added before () was achieved. (Example 3) In this example, the contamination method was changed. That is, in Example 1, copper was the pollution source, but in this Example, Ce was the pollution source. Note that Ce has a large oxidation potential and is a metal that is more difficult to remove than copper.

[Table 6]

This substrate was subjected to wet treatment by the wet treatment methods shown in Table 7 as in Example 1. The results of wet treatment are also shown in Table 7.

[0086]

[Table 7] * 1 Anode water obtained by electrolysis after adding hydrochloric acid * 2 Anode water obtained by electrolysis of ultrapure water with electrolyte added * 3 Anode water obtained by electrolytic decomposition after adding hydrochloric acid With additional hydrofluoric acid

From the results of the wet treatment shown in Table 7, it can be seen that the one to which the electrolyte was added exhibited a cleaning effect superior to that to which the electrolyte was not added. Further, it can be seen that the cleaning effect is higher when hydrofluoric acid is added together with hydrochloric acid than when hydrochloric acid is added alone.

(Example 4) A glass substrate for a liquid crystal display, the surface of which was contaminated with alumina (Al ₂ O ₃ ) particles, was prepared.
As a result of single-wafer treatment with ultrapure water, ammonia hydrogen peroxide solution, electrolytic cathodic water (pH 8), ultrapure water ultrasonic treated water, electrolytic cathodic water ultrasonic treated water, electrolytic cathodic water ultrasonic treated water removes particles It was found that the effect is extremely higher than the effect expected by treating electrolytic cathodic water alone, ultrapure water ultrasonically treated water and continuous treatment of these two treatments, and that the treatment liquid wastewater treatment is easy. .

The wet treatment method shown in Table 7,
The electrolyzed cathode water (pH 8) used in Examples 1 and 2 was produced by the following method using the electrolyzer shown in FIG.

That is, first, ultrapure water is introduced into the pipe 309,
It was introduced and circulated through the anode chamber 302, the intermediate chamber 303, and the cathode chamber 304 via 310, 311, and 312. At that time, from the electrolyte addition devices 313 and 314 to the introduction pipe 31
0, 312, HCl and NH ₄ respectively in the introduction pipe.
Continuously injecting OH, adjusting the pH to 2 in the anode chamber and adjusting the pH to 8 in the cathode chamber, a direct current is passed through the electrodes 305 and 306 to continuously generate an electrolysis reaction, and to continuously generate electrolytic anode water. (PH 2) and electrolytic cathode water (pH 8) were obtained.

Further, the wet treatment apparatus shown in FIGS. 1 and 5 is used to carry out the same method as described above (however, the electrolyte is added from the electrolyte addition apparatuses 130 and 131 to the introduction pipe 3).
15, 317) to obtain electrolyzed anode water (pH
2), the surface of the object to be treated was treated through the steps of irradiating the electrolytic catholyte (pH 8) with ultrasonic waves or without ultrasonic wave irradiation.

[0092]

[Table 8]

[0093]

[Table 9]

In Table 9, is the example and the others are comparative examples. Among the comparative examples, ~ is a comparative example in which ultrasonic irradiation is not performed, and, is a comparative example in which ultrasonic irradiation is performed but chemicals and the like are different. Further, is a comparative example in which the electrolyte was added before electrolysis.

As can be seen from Table 9, when the ultrasonic wave is irradiated, the removal efficiency is better than in the case where the ultrasonic wave is not irradiated.
It is not possible to reduce the residual number below the level of 100 cm ² (see,). However, it is possible to reduce the remaining number from the level of 500 pieces / 100 cm ² only when electrolyzed water is used. In particular, when ammonia is added and the pH is adjusted to (8), the cleanliness achieved is significantly improved. And, when the electrolyte is added, the cleaning effect is superior to that when the electrolyte is not added.

(Example 5) In this example, the influence of the frequency of ultrasonic waves was investigated.

That is, the contamination method and the wet treatment method were the same as in Example 2, but various frequencies were examined.

The results are shown in Table 10.

[0099]

[Table 10] Unit: Number / 100 cm ²

As shown in Table 10, removal of less than 5 μm or more than 5 μm is not sufficient below 30 kHz. Therefore, it is understood that the irradiation of ultrasonic waves of 30 kHz or higher is necessary.

Particularly, it can be seen that the particles of 5 μm or less are drastically reduced at 1 MHz or more.

Both large particles and small particles can be reliably removed by performing cleaning while changing the frequency from 3 MHz to 32 kHz (from high frequency to low frequency) and from 32 kHz to 3 MHz (from low frequency to high frequency). Is.
The latter is more preferred.

Example 6 In this example, the apparatus shown in FIG. 4 was used to remove the dissolved gas in the anode water and cathode water, and the effect of the amount of dissolved gas was investigated.

The apparatus shown in FIG. 4 is the same as the apparatus shown in FIG.
The amount of dissolved oxygen in the treated water (1) 115 was changed by interposing a deaerator 410 between 0 and 0. An exhaust pump 411 is connected to the deaerator 410, and a gas permeable film 412 is formed inside the deaerator 410, whereby deaeration is performed.

The amount of dissolved oxygen in the treated water (1) 115 was measured by sound pressure. In other words, the treated water (1) 115 of the wet treatment unit 120 is attached to the probe 413 (HUS made by Honda Electronics).
-5-PS) is soaked in the probe 413 and the sound pressure gauge 414
(HUS-5 manufactured by Honda Electronics) was connected.

The results are shown in Table 11.

[0107]

[Table 11] * SiO ₂ particles on a-Si (0.5 μm or more) * Unit: number / 100 cm ²

As shown in Table 11, at 10 ppm or less, the number of residual particles sharply decreases and the cleanliness is remarkably improved.

[0109]

【The invention's effect】

(Claim 1) The amounts of chemicals and pure water used, and the drainage load from the cleaning process are dramatically reduced. The metal removal effect can be enhanced without increasing the load on the wastewater treatment device.

Further, it is possible to obtain an even higher cleaning effect than before, and it is possible to further reduce the amount of ultrapure water used and the amount of chemicals used, thereby reducing the amount of waste water or waste chemicals. In particular, it has a high ability to remove Ce, which has a high oxidation potential and is difficult to remove. As in the case of adding an electrolyte before electrolysis, the ability to remove Ce is excellent.

(Claim 2) It is possible to clean the entire surface of a large area substrate, and therefore it is particularly effective when applied to a substrate for a liquid crystal display device.

(Claim 3) The number of treatments per unit time can be increased by immersing a large number of treatment objects at one time. Further, it is possible to enhance the effect of removing the contamination of the object having poor wettability.

(Claim 4) Since the object to be processed is always cleaned with a fresh cleaning liquid, recontamination is extremely small and the object to be processed can be brought into a highly cleaned state.

(Claims 5 and 6) The object to be treated can be kept in a more highly clean state.

(Claim 7) The electric resistance between the anode electrode and the cathode electrode can be reduced, and electrolytic ionic water can be obtained at a low voltage.

(Claim 8) Since the intermediate chamber is filled with the conductive solid electrolyte, the electric resistance between the anode electrode and the cathode electrode can be reduced, and electrolytic ionized water can be obtained at a low voltage.

(Claim 9) A high particle removability or a high metal removability is exhibited.

(Claim 10) The object to be treated can be kept in a much higher clean state.

(Claim 11) The electric resistance between the anode electrode and the cathode electrode can be reduced, and electrolytic ionic water can be obtained at a low voltage.

(Claim 12) The electric resistance between the anode electrode and the cathode electrode can be reduced, and electrolytic ionic water can be obtained at a low voltage.

[0121]

[0122] In (claims 1-3) low energy, can be removed organics, contaminants. (Others) In the present invention, ultrasonic irradiation intensity, ion species,
It is always stable by controlling the ON concentration and redox potential.
Cleaning can be realized, resulting in stable and highly clean processing
can do.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a wet processing apparatus according to an embodiment.

FIG. 2 is a conceptual diagram of a wet processing apparatus according to another embodiment.

FIG. 3 is a conceptual diagram of an electrolyzer in the wet processing apparatus according to the first embodiment.

FIG. 4 is a conceptual diagram of an apparatus used in Example 5.

FIG. 5 is a conceptual diagram of a wet processing apparatus according to a fourth embodiment.

[Explanation of symbols]

101 Introduction piping system, 102 electrolyzer, 103 Anode chamber, 104 anode electrode, 105 Anode water derivation piping system, 106 cathode chamber, 107 cathode electrode, 108 Cathode water derivation piping system, 109 ultrasonic irradiation device (1), 110 Object to be processed (1), 111 Ultrasonic irradiation device (2), 112 Processing object (2), 113 DC power supply, 114 septa, 115 Treated water (1), 116 treated water (2), 117, 118 oscillators, 120, 121 wet processing section, 130, 131 Electrolyte addition means, 201 Introduction piping system, 202 electrolyzer, 203 Anode chamber, 204 anode electrode, 205 Anode water derivation piping system, 206 cathode chamber, 207 cathode electrode, 208 Cathode water derivation piping system, 209 Ultrasonic irradiation device (1), 210 Processing object (1), 211 Ultrasonic irradiation device (2), 212 Object to be processed (2), 213 DC power supply, 214 diaphragm, 215 Object holding and rotating device (1), 216 Workpiece holding and rotating device (2), 217 Treated water (1), 218 Treated water (2), 301 electrolyzer, 302 Anode chamber, 303 Intermediate room, 304 cathode chamber, 305 anode electrode, 306 cathode electrode, 307 diaphragm (ion exchange membrane), 308 Solid electrolyte (ion exchange resin), 309 Introduction piping system, 310 Anode chamber introduction pipe, 311 Intermediate room introduction piping, 312 cathode chamber introduction pipe, 313 Anode side electrolyte addition device, 314 cathode side electrolyte addition device, 315 Anode chamber outlet pipe, 316 Intermediate chamber outlet piping, 317 cathode chamber outlet pipe, 318 Anode water side filter, 319 Cathode water side filter, 410 deaerator, 411 exhaust pump, 412 gas permeable membrane, 413 probe, 414 Sound pressure gauge.

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-6-91271 (JP, A) JP-A-5-269450 (JP, A) JP-A-4-256473 (JP, A) JP-A-60- 51582 (JP, A) JP 6-97141 (JP, A) JP 7-142395 (JP, A) JP 9-17765 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B08B 3/12 B08B 3/10 B08B 3/02 B08B 3/08

Claims (13)

(57) [Claims] 1. A method of wet-treating an object to be treated with anode water or cathode water obtained by introducing pure water or ultrapure water into a predetermined electrolyzer and electrolyzing the same. Add to the anode water or
A wet treatment method characterized in that a wet treatment is performed by adding a denatured substance to the cathode water and irradiating an ultrasonic wave of 30 kHz or more. 2. The wet processing method according to claim 1, wherein the object to be processed is a semiconductor substrate, a magnetic substrate or a liquid crystal display substrate. 3. The wet treatment method is a wet treatment method carried out in a state in which a material to be wet-treated is immersed in a container for storing or circulating the anode water or the cathode water, wherein the ultrasonic wave irradiating means is the anode. Irradiation is performed while the object to be treated is immersed in a container for storing or circulating water or cathode water.
The wet treatment method described. 4. The wet treatment method is a wet treatment method in which the anode water or the cathode water is continuously jetted or dropped toward a workpiece from a predetermined nozzle, and the ultrasonic wave irradiating means comprises: 3. The anode water or the cathode water is irradiated to at least a part of a liquid feeding piping system of the anode water or the cathode water in an upstream portion of the predetermined nozzle. Wet treatment method. 5. The pure water obtained by a pure water producing apparatus or an ultrapure water producing apparatus equipped with at least one of an ion exchange apparatus, a membrane processing apparatus, and a distillation apparatus, or a liquid introduced into the electrolyzer. The wet treatment method according to any one of claims 1 to 4, wherein the wet treatment method is ultrapure water or an aqueous solution of an electrolyte obtained by adding a predetermined electrolyte to the pure water or ultrapure water. 6. The electrolyzer comprises three chambers: an anode chamber having an anode electrode, a cathode chamber having a cathode electrode, and an intermediate chamber partitioned by a pair of diaphragms between the anode chamber and the cathode chamber. The wet treatment method according to any one of claims 1 to 5, wherein raw water is introduced into each of the three chambers of the electrolyzer, and the treatment liquid is discharged from each of the three chambers. 7. The electrolyzer comprises an anode chamber and / or
Alternatively, the diaphragm that separates the cathode chamber and the intermediate chamber is an electrolysis device that is an ion exchange membrane.
7. The wet treatment method according to any one of 6 to 6. 8. The wet treatment method according to claim 7, wherein the electrolyzer is an electrolyzer in which an intermediate chamber is filled with a solid electrolyte. 9. An electrolyzer for electrolyzing water, an introducing pipe system for introducing water into the electrolyzer, and an anode chamber and a cathode chamber formed in the electrolyzer via a diaphragm, respectively. An electrode pair of an anode electrode and a cathode electrode provided, a DC power source for supplying a DC current to the electrode pair, and an anode water and a cathode water, which are treatment liquids obtained by the electrolyzer, are taken out separately. And a means for adding an electrolyte to the anode water and / or the cathode water obtained in the electrolyzer,
Ultrasonic wave irradiating means connected to the downstream of the outlet piping system and capable of irradiating ultrasonic waves of 30 kHz or more, and for irradiating the anode water and / or the cathode water with ultrasonic waves to wet-treat the object to be treated. Wet processing part of the above. 10. The electrolyzer comprises an anode chamber having an anode electrode, a cathode chamber having a cathode electrode,
It is composed of three chambers, an intermediate chamber, which is divided by a pair of diaphragms between the anode chamber and the cathode chamber, and an introducing piping system for introducing raw water into each of the three chambers of this electrolyzer, and a treatment liquid from each of these three chambers. The wet processing apparatus according to claim 9, further comprising: 11. The electrolysis device according to claim 9, wherein the electrolysis device is an electrolysis device in which the diaphragm that separates the anode chamber and / or the cathode chamber from the intermediate chamber is an ion exchange membrane. Wet processing equipment. 12. The wet treatment apparatus according to claim 11, wherein the electrolysis apparatus is an electrolysis apparatus in which an intermediate chamber is filled with a solid electrolyte. The upstream portion of wherein said ultrasonic irradiation means, to 9 claims, characterized in that it comprises a deaerator for the dissolved gas in the anode water and 10ppm or less in the derivation pipeline 1 2 The wet processing apparatus according to any one of 1 .