TWI852531B - Wet membrane plate and a preparation method thereof - Google Patents

Abstract

The present invention discloses a wet membrane plate and a preparation method thereof. By applying plasma treatment on the polymer layer, the surface of the polymer layer forms multi-scales of millimeter, micron, and nanocomposite structures. The overall hydrophilicity of the wet membrane plate is effectively enhanced by plasma treatment, thereby prolonging the contact time of the airborne molecular contamination when the exhaust gas passing through the wet membrane plate.

Description

Wet membrane plate and preparation method thereof

The present invention relates to a wet membrane plate and a preparation method thereof, in particular to a wet membrane plate and a preparation method thereof which is used in a wet scrubber and increases the contact time between spray and exhaust gas.

In the ultra-large integrated circuit (ULSI) process, wafer cleaning technology and its cleanliness are often one of the important factors affecting the yield, component quality and reliability of the wafer process. Therefore, the wafer needs to be cleaned in the relevant process to meet the cleanliness requirements.

Wafer cleaning involves soaking a whole batch or a single wafer in chemicals or using pure water to clean the wafer surface, mainly to remove contaminants such as microparticles, organic pollutants, inorganic substances, metal ions and other impurities.

Currently, the industry is more likely to use wet cleaning methods, and the most accepted one is the RCA Clean method, which was developed by RCA in the 1960s. The cleaning principle is to use different chemical formulas for cleaning, such as Standard Cleaning Solution 1 (SC-1) and Standard Cleaning Solution 2 (SC-2).

When using chemical formulas such as SC-1 (APM), SC-2 (HPM), SPM, DHF and BHF for cleaning, a large amount of acid gas, alkaline gas and volatile organic matter are often discharged as mixed waste gas. Currently, the removal efficiency of volatile organic matter has not been able to achieve a good effect.

Volatile organic compounds (VOCs) are a general term for air pollutants that are organic compounds with a boiling point below 250°C under atmospheric pressure. The environmental pollution problems they cause are widely present in all types of industries.

The most common volatile organic compounds in industry are acetone (Acetone), isopropyl acetone (IPA), propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), dimethyl sulfoxide (DMSO), ethanolamine (MEA), nitrogen-methyl 2-tetrahydropyrrolidone (NMP), diethylene glycol monobutyl ether (BDG), tetramethylammonium hydroxide (TMAH) and other components.

In solving the problem of mixed exhaust gas, a wet scrubber is usually introduced to treat pollutants (acids, alkalis, and organic substances) in the exhaust gas. Wet scrubbers usually use scrubbing liquid as a water medium for mass transfer. Through the spray humidification system in the wet scrubber (using a pump to pressurize the scrubbing liquid to produce atomized particles of a specific diameter), the spray and the incoming exhaust gas undergo inertial collision, mass transfer, and dissolution to remove pollutants (acids, alkalis, and organic substances) in the exhaust gas.

However, the use of water spraying materials in wet scrubbers is limited by the size of the plant equipment. It is not possible to extend the contact time between atomized particles and exhaust gas by installing a large number of water spraying materials (which requires expanding the floor space).

Therefore, how to make the contact time between the atomized particles and the exhaust gas in the wet scrubber longer and achieve good purification under the condition of limited space in the factory equipment is a problem that researchers in this technical field want to solve.

The main purpose of the present invention is to provide a wet membrane and a preparation method thereof, wherein a polymer layer is subjected to plasma treatment to form a millimeter, micrometer and nanometer composite structure on the surface due to plasma. The plasma treatment is also used to improve the hydrophilicity of the wet membrane as a whole, thereby prolonging the contact time between the atomized particles and the exhaust gas when passing through the wet membrane.

In order to achieve the above-mentioned purpose, the present invention discloses a method for preparing a wet membrane plate, the steps of which include: taking a molded plate; coating a crystalline polymer solution on the surface of the molded plate, and then performing a hot pressing treatment to form a polymer layer on the molded plate with the crystalline polymer solution, wherein the polymer layer is a non-planar structure; and using a reactive gas to perform a plasma treatment on the polymer layer to make the polymer layer hydrophilic and rough, and form a wet membrane plate; wherein the surface of the wet membrane plate is a millimeter, micrometer and nanometer composite structure, and the crystalline polymer solution is selected from one of the group consisting of a polyethylene terephthalate, a nylon, a polybutylene terephthalate, a polyacetal and a polypropylene, or a combination thereof.

The present invention provides an embodiment, which is a method for preparing a wet film sheet, wherein before the step of taking a formed sheet, the method further comprises the step of: taking a plastic and performing a forming process at a temperature of 150°C to 200°C, wherein the forming process is a rolling forming process, a compression forming process or a hot pressing forming process, and the plastic is selected from one of the group consisting of polyethylene terephthalate, nylon, polybutylene terephthalate, polyacetal and polypropylene, or a combination thereof.

The present invention provides an embodiment, which is a method for preparing a wet membrane plate, wherein in the step of forming a polymer layer on the shaped plate from the crystalline polymer solution, the surface of the non-planar structure is a micron structure.

The present invention provides an embodiment, which is a method for preparing a wet membrane, wherein in a step of performing a hot pressing treatment, the temperature of the hot pressing treatment is between 60 and 70°C.

The present invention provides an embodiment, which is a method for preparing a wet membrane, wherein in the step of using a reactive gas to perform a plasma treatment on the polymer layer, the fixed frequency of the plasma treatment is 13.56 MHz, the pressure of the plasma treatment is 10 mTorr, the power of the plasma treatment is between 10 W and 100 W, and the etching time of the plasma treatment is between 1 and 5 minutes.

Furthermore, the present invention discloses a wet membrane plate, the structure of which includes: a molded plate; and a polymer layer, the polymer layer is a non-planar structure, which is arranged on the upper surface of the molded plate; wherein the upper surface of the wet membrane plate is a millimeter, micrometer and nanometer composite structure, and the steps of preparing the wet membrane plate include: taking a molded plate; after applying a crystalline polymer solution on the surface of the molded plate, performing a hot pressing treatment so that the crystalline polymer solution forms a polymer layer on the molded plate, the polymer layer is a non-planar structure; and using a reactive gas to perform a plasma treatment on the polymer layer to make the polymer layer hydrophilic and roughened, and form a wet membrane plate.

The present invention provides an embodiment, which is a wet film sheet, wherein the height of the formed sheet is between 1 mm and 10 mm.

The present invention provides an embodiment, which is a wet film plate, wherein the shaped plate is a corrugated plate, a sawtooth plate or an arc plate.

The present invention provides an embodiment, which is a wet film plate, wherein the polymer layer is formed by coating a crystalline polymer solution on the upper surface of the formed plate and then performing a heat pressing treatment.

The present invention provides an embodiment, which is a wet membrane, wherein the thickness of the polymer layer is between 2 and 3 microns.

In order to enable you to have a deeper understanding and knowledge of the features and effects of the present invention, we would like to provide practical examples and accompanying explanations as follows:

In view of the fact that the contact time between atomized particles and exhaust gas is too short, and thus the purification efficiency is low, the present invention proposes a wet membrane plate and a preparation method thereof to solve the problem caused by the prior art.

The following will further describe the characteristics, structure and method of preparing a wet membrane plate of the present invention:

Please refer to Figure 1, which is a flow chart of the steps of one embodiment of the present invention. As shown in Figure 1, a method for preparing a wet membrane plate comprises the following steps:

S1: Take the formed sheet;

S2: After applying the crystalline polymer solution on the surface of the formed sheet, a heat-pressing treatment is performed to make the crystalline polymer solution form a polymer layer on the formed sheet, and the polymer layer is a non-planar structure; and

S3: Use reactive gas to perform plasma treatment on the polymer layer to make it hydrophilic and rough, and form a wet membrane.

Before step S1, the method further includes step S0: taking the plastic and subjecting it to a molding process at a temperature of 150°C to 200°C.

As shown in step S0, a plastic is subjected to a molding process at a temperature of 150°C to 200°C to form a molded sheet 11 used in step S1. The molding process is a rolling molding process, a die molding process or a hot pressing process, and the plastic is selected from the group consisting of polyethylene terephthalate, nylon, polybutylene terephthalate, polyacetal and polypropylene, or a combination thereof.

The height of the formed plate 11 formed in step S0 is between 1 mm and 10 mm. In addition to a flat plate, the formed plate 11 can be a corrugated plate, a sawtooth plate, or an arc plate, etc. (please refer to FIGS. 2A to 2C, which are schematic structural diagrams of the formed plate of an embodiment of the present invention). The shape of the formed plate 11 can provide gas flow, and the shape of the formed plate 11 is not limited to this.

Next, as shown in step S2, after a crystalline polymer solution is coated on the surface of the molded plate 11, a heat pressing treatment is performed to form a polymer layer 12 on the molded plate 11 with the crystalline polymer solution. The crystalline polymer solution is selected from one of the group consisting of polyethylene terephthalate, nylon, polybutylene terephthalate, polyacetal and polypropylene, or a combination thereof.

The preparation example of the crystalline polymer solution is as follows: polymer particles such as polyethylene terephthalate are dissolved in 2-chlorophenol and stirred at 60°C until completely dissolved. The solution formula is a 7% by weight polymer particle/2-chlorophenol mixture. The thickness of the applied crystalline polymer solution is controlled to be 2-3 microns, and it is heated in an oven at 60°C for 3 hours and then cooled naturally.

In addition, the hot pressing treatment is to apply the crystalline polymer solution on the forming plate 11, and then take a PDMS (Polydimethylsiloxane) stamp with a hierarchical millimeter and micrometer structure to softly emboss the crystalline polymer solution on the forming plate 11 at a temperature of 60 to 70°C, and roll press the crystalline polymer solution by the rolling forming treatment, the molding treatment or the hot pressing treatment, and control it within 10 to 30 seconds, and the pressure is controlled within 2 to 10kg/ ^cm2 , and then it is heated in an oven at 60°C for 3 hours and then naturally cooled. At this time, the crystalline polymer solution forms the polymer layer 12 on the forming plate (the PDMS stamp can be peeled off).

Among them, the preparation of PDMS stamp: PDMS main agent and hardener are first mixed evenly in a beaker at a weight ratio of 10:1, and then poured on the mold (with a hierarchical millimeter and micrometer structure, prepared by laser etching). Because there is a large amount of gas in the process, and in order to be able to discharge the air in the solution, the culture dish is first moved to a vacuum tank for vacuuming, so that all the air in the entire system can be removed. Then move the culture dish to a heating plate and heat it at 60℃ for more than 12 hours to enable the PDMS stamp to cure completely. After the reaction is completed, the PDMS stamp with a hierarchical millimeter and micrometer structure can be torn off.

At this time, the polymer layer 12 formed by using the PDMS stamp is a non-planar structure (a hierarchical structure) with a thickness between 2 and 3 microns. The surface of the non-planar structure has a millimeter and micron structure.

Finally, as shown in step S3, a reactive gas is used to perform a plasma treatment on the polymer layer to make the polymer layer hydrophilic and rough, and form a wet membrane plate 1.

The plasma treatment is performed by using a radio frequency capacitively coupled plasma driven by a metal ring electrode, and the object to be treated with plasma is placed inside a plasma chamber, wherein the fixed frequency of the plasma treatment is 13.56 MHz, the pressure of the plasma treatment is 10 mTorr, the power of the plasma treatment is between 10 W and 100 W, preferably less than 100 W, and the etching time of the plasma treatment is between 1 and 5 minutes, preferably less than 5 minutes. Furthermore, the reactive gas (O ₂ ) is used when the distance between the metal ring and the substrate is 4.6 cm and the oxygen flow rate is 2.1 sccm. In addition to oxygen, the reactive gas may be ammonia or atmospheric air.

Moreover, the main advantages of RF capacitive coupled plasma are: there is no problem of electrode corrosion or contamination, the material of the electrode will not interfere with the plasma state, and because the wavelength intensity of the electric field is greater than the size of the container, a uniform plasma can be produced.

Furthermore, after the plasma treatment, the surface of the wet membrane 1 is roughened and hydrophilized, and in addition to the millimeter and micrometer structures, a nanometer structure is further formed. Therefore, the surface of the wet membrane 1 has a high roughness of millimeter, micrometer and nanometer composite structure. Because, during the plasma treatment process, the weaker bonds on the surface of the material will first be destroyed by the plasma active particles, and then replaced by the highly reactive functional groups generated by the dissociation of the reactive gas, so as to achieve the effect of activating the polymer surface. Common reactive functional groups include -O, -COOH and -NH2, etc., which can be used to change the reactivity of the material surface or improve the wettability, adhesion and other functions, thereby achieving the diffusibility of the washing liquid.

Please refer to Figure 3, which is a schematic diagram of the structure of a wet film sheet of an embodiment of the present invention. After the above steps, a wet film sheet 1 of the present invention comprises: the formed plate 11 (the height is between 1mm and 10mm, and a flat plate is used as an example) and the polymer layer 12 (the thickness is between 2 and 3 microns), the polymer layer is the non-planar structure (hierarchical), which is disposed on the upper surface of the formed plate through the hot pressing treatment (forming a millimeter and micron structure at this time), and the plasma treatment is performed to make the polymer layer have a roughened surface 121, and further form a nanostructure, wherein the upper surface of the wet film sheet is a millimeter, micron and nano composite structure with high roughness.

Furthermore, the experimental test of the wet film 1 of the present invention shows that after the plasma treatment (O ₂ ), the contact angle of the water drop on the wet film decreases with the increase of the plasma etching time. Table 1, experimental data table of water drop contact angle Plasma treated surface 0 minutes 1 minute 2 minutes 3 minutes 4 minutes 5 minutes Water drop contact angle 51∘ 32∘ 18∘ 3∘ 2∘ 2∘

The contact angle refers to the angle formed when the liquid/gas interface contacts the solid surface. The contact angle is a system of three different interfaces interacting with each other. Moreover, the contact angle is also an important indicator for measuring the hydrophilicity and hydrophobicity of the material itself. The smaller the contact angle between the material and the water droplet, the higher the hydrophilicity of the material. It shows that the present invention can indeed improve the hydrophilicity of the wet membrane plate 1 after plasma treatment.

Please refer to Figure 4: It is a scanning electron microscope image of an embodiment of the present invention. As shown in the figure, it can be seen from the observation of the scanning electron microscope that after the plasma treatment (O ₂ ), the hierarchical surface of the wet film 1 becomes rougher as the etching time of the plasma treatment ((a) 0, (b) 1, (c) 2, (d) 3, (e) 4, (f) 5 minutes) increases, indicating that the plasma treatment not only makes the wet film more hydrophilic as a whole (its water drop contact competition gradually decreases), but also further forms a roughened surface 121 to increase the contact time between the atomized washing particles and the exhaust gas.

For this purpose, compared with the conventional technology that requires sandblasting and is made of inorganic materials, the present invention uses crystalline organic polymer materials to prepare wet membranes with millimeter and micrometer structures, and the wet membranes are treated with plasma surface to achieve high roughness wet membranes with millimeter, micrometer and nanometer structures, and the hydrophilic properties that are quickly improved after plasma treatment are effectively improved to effectively enhance the diffusion of atomized particles when in contact with exhaust gas, thereby increasing the contact time and area.

Therefore, this invention is novel, progressive and can be used in the industry. It should undoubtedly meet the patent application requirements of the Patent Law of our country. Therefore, we have filed an invention patent application in accordance with the law and pray that the Bureau will approve the patent as soon as possible. I am deeply grateful.

However, the above is only a preferred embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. All equivalent changes and modifications made according to the shape, structure, features and spirit described in the patent application scope of the present invention should be included in the patent application scope of the present invention.

S1, S2, S3: Steps 1: Wet membrane sheet 11: Forming sheet 12: Polymer layer 121: Roughening surface

FIG. 1 is a flow chart of the steps of one embodiment of the present invention;

Figures 2A-2C: Schematic diagram of the structure of a formed plate of one embodiment of the present invention

FIG. 3 is a schematic structural diagram of a wet membrane plate according to an embodiment of the present invention; and

FIG. 4 is a scanning electron microscope image of an embodiment of the present invention.

S1, S2, S3: Step flow

Claims (10)

A method for preparing a wet film comprises the following steps: taking a shaped plate; applying a crystalline polymer solution on the surface of the shaped plate, taking a polydimethylsiloxane stamp having a hierarchical millimeter and micrometer structure and performing a heat-pressing treatment to make the crystalline polymer solution form a polymer layer on the shaped plate, wherein the polymer layer is a non-planar structure; and using a reactive gas to heat the polymer layer. The molecular layer is subjected to a plasma treatment to hydrophilize and roughen the polymer layer to form a nanostructure, and a wet membrane is formed; wherein the surface of the wet membrane is a composite structure of millimeters, micrometers and nanometers, and the crystalline polymer solution is selected from one of the group consisting of polyethylene terephthalate, nylon, polybutylene terephthalate, polyacetal and polypropylene, or a combination thereof. The method for preparing a wet film sheet as described in claim 1, wherein before the step of obtaining a formed sheet, further comprises the step of: obtaining a plastic and subjecting it to a forming process at a temperature of 150°C to 200°C, wherein the forming process is a rolling forming process, a compression forming process or a hot pressing forming process, and the plastic is selected from one of the group consisting of the polyethylene terephthalate, the nylon, the polybutylene terephthalate, the polyacetal and the polypropylene, or a combination thereof. The method for preparing a wet membrane sheet as described in claim 1, wherein in the step of forming a polymer layer on the shaped sheet from the crystalline polymer solution, the surface of the non-planar structure is a micron structure. A method for preparing a wet membrane sheet as described in claim 1, wherein in the step of performing a hot pressing treatment, the temperature of the hot pressing treatment is between 60 and 70°C. A method for preparing a wet membrane as described in claim 1, wherein in the step of using a reactive gas to perform a plasma treatment on the polymer layer, the fixed frequency of the plasma treatment is 13.56 MHz, the pressure of the plasma treatment is 10 mTorr, the power of the plasma treatment is between 10 W and 100 W, and the etching time of the plasma treatment is between 1 and 5 minutes. A wet film plate, the structure of which includes: a molded plate; and a polymer layer, the polymer layer is a non-planar structure, which is arranged on the upper surface of the molded plate; wherein the upper surface of the wet film plate is a millimeter, micrometer and nanometer composite structure, and the steps of preparing the wet film plate include: taking a molded plate; after applying a crystalline polymer solution on the surface of the molded plate, taking a polydimethylsiloxane stamp with a hierarchical millimeter and micrometer structure to perform a hot pressing treatment, so that the crystalline polymer solution forms a polymer layer on the molded plate, the polymer layer is a non-planar structure; and using a reactive gas to perform a plasma treatment on the polymer layer, so that the polymer layer is hydrophilized and roughened to form a nanostructure, and a wet film plate is formed. A wet film sheet as described in claim 6, wherein the height of the formed sheet is between 1 mm and 10 mm. A wet membrane sheet as described in claim 6, wherein the shaped sheet is a corrugated sheet, a sawtooth sheet or an arc-shaped sheet. The wet film sheet as described in claim 6, wherein the polymer layer is formed by applying a crystalline polymer solution on the upper surface of the formed sheet and then performing a heat pressing treatment. A wet membrane as described in claim 6, wherein the thickness of the polymer layer is between 2 and 3 microns.