Preparation method of mask dust prevention system for extreme ultraviolet lithography

Abstract

The present invention relates to a method for preparing a mask dustproof system for extreme ultraviolet lithography, comprising the following steps: preparing a ceramic frame; preparing an organic fluoropolymer film and testing its uniformity; bonding the ceramic frame and the organic fluoropolymer film; depositing a catalyst on the surface of the organic fluoropolymer film; forming a graphene-carbon nanotube composite film; thinning the graphene-carbon nanotube composite film; bonding a high-temperature-resistant rubber buffer layer to the lower end of the ceramic frame; and testing its strength and airtightness. Compared with traditional methods, this method is simpler for preparing large-area films with uniform thickness, does not require manipulation of carbon nanotube films 8 to 15 nm thick, thus avoiding film damage and achieving a high yield. The mask dustproof system prepared by the present invention has a transmittance of over 90% under irradiation with ultraviolet light of a wavelength of 13.5 nm. Compared with traditional nitrocellulose, organic fluororesin, and polycrystalline silicon films, this method has a higher transmittance and produces clearer images from the mask system.

Description

Technical Field

[0001] The present invention relates to the technical field of photolithography equipment, and in particular to a method for preparing a mask dust-proof system for extreme ultraviolet photolithography. Background Art

[0002] During the photolithography process, a dust protection system is typically installed on the mask or reticle to prevent dust from adhering to the mask. This system consists of a protective film stretched over one end of a frame that encloses the mask pattern. As chip patterns become increasingly refined, photolithography machines are using shorter-wavelength EUV light instead of DUV light. EUV mask dust protection systems must achieve a transmittance of at least 90% at a 13.5nm wavelength, be resistant to high temperatures, and have a uniform thickness.

[0003] Under 13.5nm wavelength light, if fluorine-based polymers or nitrocellulose are used to form the film, the transmittance is less than 50% and it cannot be used. If polycrystalline silicon material is used to form the film, the transmittance is between 80 and 90%, and a lot of heat is generated during use, which cannot meet high-demand usage scenarios. When the thickness of the graphene film is 8-15nm, the transmittance is more than 90%, but the strength and thermal oxidation resistance of the film are poor. When the thickness of the carbon nanotube film is 8-15nm, the transmittance is more than 90%, and the strength and thermal oxidation resistance are good, but it is difficult to prepare and the cost is very high.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the Invention

[0005] In response to the deficiencies of the prior art, an embodiment of the present invention discloses a method for preparing a dustproof system for a mask used in extreme ultraviolet lithography, so as to solve the problems of insufficient transmittance, complex process and high cost in preparing the protective film of the dustproof system.

[0006] The technical solutions adopted in the present invention are as follows:

[0007] A method for preparing a mask dust prevention system for extreme ultraviolet lithography comprises the following steps: preparing a ceramic frame; preparing an organic fluoropolymer film and testing its uniformity; bonding the ceramic frame and the organic fluoropolymer film; depositing a catalyst on the surface of the organic fluoropolymer film; forming a graphene-carbon nanotube composite film; thinning the graphene-carbon nanotube composite film; bonding a high-temperature resistant rubber buffer layer to the lower end of the ceramic frame; and testing its strength and airtightness.

[0008] A further technical solution is that the step of preparing the ceramic frame includes:

[0009] The following components are added in parts by weight in sequence: 1 to 10 parts of nano-zirconium oxide, 10 to 50 parts of zirconium carbonate, 1 to 10 parts of boric acid, 1 to 10 parts of phosphoric acid, 1 to 10 parts of vanadic acid, 1 to 10 parts of tungstic acid, and 1 to 10 parts of molybdic acid, mixed evenly, and a ceramic body is prepared according to the size.

[0010] The ceramic body is placed in a hot pressing sintering furnace, and the program is started: the sintering temperature is 1000-1500°C, the pressure is 100-200 MPa, a voltage of 2-10V and a pulse current of 1000-50000A are applied to the body to obtain a ceramic frame.

[0011] A further technical solution is that the steps of preparing the organic fluoropolymer film and testing its uniformity include:

[0012] Prepare an organic fluoropolymer film of any one of fluorocarbon polymers such as amorphous fluororesin film, polyperfluoroalkyl acrylate film, polytetrafluoroethylene, fluoroethylene propylene copolymer, polyperfluoropropylene and polytrifluoroethylene by any one of spin coating, turning stretching, vapor deposition, phase separation and electrospinning methods, wherein the thickness of the organic fluoropolymer film is 0.06 to 0.1 μm;

[0013] The transmittance and haze of multiple points on the organic fluoropolymer film were tested using a transmittance and haze tester. The light source band was 100nm to 300nm, and the transmittance range was 95.00% ± 0.5%. Films that exceeded the tolerance range were scrapped.

[0014] A further technical solution is to use a ceramic adhesive to bond the ceramic frame and the organic fluoropolymer film; the preparation method of the ceramic adhesive is: add the following components in parts by weight in sequence: 0.1 to 1 part of fluorosilicone resin, 10 to 50 parts of potassium silicate, 2 to 10 parts of zirconium oxide, 1 to 50 parts of aluminum phosphate, and 1 to 50 parts of calcium borate, mix them evenly, and obtain a ceramic adhesive.

[0015] A further technical solution is that the step of depositing a catalyst on the surface of the organic fluoropolymer film comprises:

[0016] The catalyst solution is used to prepare aerosol through an aerosol generator, with colloidal particle size of 5-50nm and concentration of 10-200ppm, and is deposited on the surface of the organic fluoropolymer film; and the organic fluoropolymer film is dried.

[0017] A further technical solution is that the method for preparing the catalyst solution comprises the following steps:

[0018] The following components in parts by weight are added in sequence: 1 part of fluorinated organic acid iron, 100-500 parts of water, 0.5-2 parts of fluorinated emulsifier, 0.1-1 part of fluorinated leveling agent, 0.1-1 part of fluorinated wetting agent, and 0.1-1 part of fluorinated atomizer; wherein the fluorinated organic acid iron is an organic acid iron compound containing at least one fluorine atom replacing a hydrogen atom; the fluorinated emulsifier is a mixture of one or more of perfluorohexanol, perfluorooctanol and perfluoroethanol; the fluorinated leveling agent is perfluorooctylpropyl acrylate, perfluoroalkylethanol polyoxyethylene ether, perfluorohexylethyltrimethoxysilane, perfluorobutylethyl acrylate, perfluorobutyl acrylate, perfluorooctylethanol ... A mixture of one or more of fluorohexyl ethyl acrylate, perfluorohexyl ethyl (meth) acrylate, perfluorooctyl ethyl acrylate, perfluorooctyl ethyl (meth) acrylate, perfluorodecyl ethyl acrylate and perfluoroalkyl ethyl acrylate; a fluorine-containing wetting agent is one or more of perfluorohexyl ethylene, perfluorooctyl ethylene, perfluorodecyl ethylene and perfluoroalkyl ethylene; a fluorine-containing atomizing agent is a mixture of one or more of pentafluoroethane iodide, perfluorobutyl iodide, perfluorohexyl iodide, perfluorooctyl iodide, perfluoroalkyl iodide, perfluorobutyl ethyl iodide, perfluorohexyl ethyl iodide, perfluorooctyl ethyl iodide and perfluoroalkyl iodide.

[0019] A further technical solution is that the steps of forming the graphene carbon nanotube composite film include:

[0020] An organic fluoropolymer film with a surface-deposited catalyst is placed in a furnace chamber, and vacuum is started to maintain a vacuum degree of 10-100 Pa; a temperature program is started: the furnace temperature is raised from room temperature to 1500-3000°C within 1-100 milliseconds and maintained for 1-20 seconds; and the temperature is cooled to room temperature at a cooling rate of 10-100°C / min.

[0021] A further technical solution is that the step of thinning the graphene carbon nanotube composite film includes:

[0022] The graphene carbon nanotube composite film is placed in a furnace chamber, vacuum is turned on, and the vacuum degree is maintained at 10-100 Pa; hydrogen is introduced and the hydrogen concentration is maintained at 0.01%-1%; the temperature is raised to 500-1500°C and maintained for 1-30 minutes; the temperature is lowered to room temperature, and the film thickness is optimal when it is 8-15 nm.

[0023] Under vacuum, at temperatures above 500°C, graphene or carbon nanotubes react with hydrogen to produce acetylene, with graphene reacting more quickly. By controlling the hydrogen concentration at a low concentration, the temperature at a moderate level, and the appropriate duration of the reaction, the graphene carbon atoms on the film surface react slowly with the hydrogen, achieving the desired film thickness reduction.

[0024] A further technical solution involves bonding a high-temperature resistant rubber buffer layer to the lower end of the ceramic frame using a high-temperature resistant organic adhesive. The rubber buffer layer mitigates stress and deformation between the dustproof system and the mask, ensuring the smoothness and light transmittance of the protective film.

[0025] A further technical solution is that the steps of testing strength and air tightness include:

[0026] After bonding the high-temperature-resistant rubber buffer layer, the mask dustproof system was installed on an aspirated air pressure pulse tester. The air pressure was set to 1 kPa, the pulse frequency was 1 Hz, the temperature was 30-80°C, and the number of pulses was 5000. The total aspirated air volume (L) was measured, and a value of <100 μL was considered acceptable. The air intake volume test under negative pressure pulses can be used to verify the membrane's integrity under pressure. A high air intake volume indicates membrane damage under negative pressure and insufficient strength.

[0027] The beneficial effects of the embodiments of the present invention are as follows:

[0028] (1) The present invention relates to a method for preparing a dust-proof mask system for extreme ultraviolet lithography. The prepared dust-proof mask system exhibits a light transmittance exceeding 90% under 13.5nm ultraviolet light. Compared to conventional nitrocellulose, organic fluorine resin, and polycrystalline silicon films, this higher light transmittance allows for clearer imaging.

[0029] (2) The traditional method for preparing carbon nanotube films involves first depositing a 10-100 nm carbon nanotube film on a substrate using chemical vapor deposition. The 10-100 nm carbon nanotube film is then peeled off from the substrate and transferred and bonded to an aluminum alloy frame. The chemical vapor deposition method is complex for preparing large-area films with uniform thickness, and subsequent peeling, transfer, and bonding operations are required for the 10-100 nm thick film, which can easily damage the film.

[0030] The method of the present invention first prepares a ceramic frame and an organic fluoropolymer film, then bonds them together. Joule flash evaporation is then used to react the organic fluoropolymer film into a graphene-carbon nanotube composite film. The Joule flash evaporation technique involves heating the furnace temperature from room temperature to above 1000°C within 100 milliseconds under vacuum and maintaining it for 1 to 20 seconds. This thermal decomposition of the polymer produces a mixture of graphene and carbon nanotubes. Compared to traditional methods, this method is simpler for preparing large-area films with uniform thickness, eliminates the need for handling the 10-100 nm thick carbon nanotube film, and reduces film damage, resulting in a high yield.

[0031] (3) Due to the low surface energy of organic fluoropolymer films, separation from the substrate is relatively easy. Organic fluoropolymers have strong cohesion, resulting in high film strength and excellent toughness. Therefore, compared to carbon nanotube films, organic fluoropolymer films are less susceptible to damage during transfer and bonding operations. Organic fluoropolymers have higher melting points than conventional organic films and do not deform or break during flash heating. The wide variety of organic fluoropolymers available and the numerous molding methods available make it easy to prepare large-area films with the required thickness.

[0032] (4) The transmittance and haze tester measures transmittance and haze at multiple points on the organic fluoropolymer film to assess the thickness and uniformity of the raw material film. By controlling the thickness and uniformity of the organic fluoropolymer film, raw materials with substandard thickness and uniformity are eliminated, thereby improving the thickness and uniformity of the subsequently prepared carbon nanotube film.

[0033] (5) A ceramic frame is used to replace the aluminum alloy frame used in traditional mask protection systems. Ceramics can withstand the high temperature conditions of 1500-3000℃ during the flash evaporation process. Nano-zirconia in the ceramic formula can increase the toughness of the ceramic frame. The combination of vanadic acid, tungstic acid and molybdenum acid used in the ceramic formula can control the phase change of the crystal structure during heating and reduce the thermal expansion coefficient. The high toughness and low thermal expansion coefficient ensure that the ceramic frame will not be broken by thermal shock during the rapid heating and cooling process during the flash evaporation process. Applying voltage and pulse current to the green body during hot pressing and sintering can increase the density and uniformity of the ceramic frame, and the subsequent flash evaporation process will not produce large stress concentration and breakage.

[0034] A ceramic adhesive is used to bond the ceramic frame to the organic fluoropolymer film. Unlike organic adhesives, ceramic adhesives do not decompose during the flash evaporation process, but instead sinter into a ceramic. Fluorosilicone resin is used in the ceramic adhesive formula to enhance the adhesive's adhesion to the organic fluoropolymer film.

[0035] (6) Fluorine-containing organic acid iron catalysts can catalyze the formation of carbon nanotubes. Without the use of a catalyst, higher temperatures and holding times are required, and the product contains less carbon nanotubes, the by-product graphene content is high, and the film strength is insufficient. Use a fluorine-containing emulsifier and a fluorine-containing atomizer, and use an aerosol generator to prepare the catalyst solution into an aerosol, which is evenly adsorbed on the surface of the film. Emulsifiers and atomizers can increase the stability of the aerosol and control the particle size. Fluorine-containing leveling agents and fluorine-containing wetting agents can promote the uniform adsorption of the catalyst aerosol on the fluorine-containing organic polymer film, avoiding poor adsorption and insufficient uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a flow chart of a method for preparing a mask dust prevention system for extreme ultraviolet lithography.

[0037] Figure 2 This is a front view structural diagram of the EUV lithography mask dust prevention system of the present invention.

[0038] Figure 3 Schematic diagram of the top view of the EUV lithography mask dust prevention system of the present invention.

[0039] In the picture:

[0040] 1. Graphene carbon nanotube composite film; 2. Ceramic frame; 3. High-temperature resistant rubber buffer layer. DETAILED DESCRIPTION

[0041] The specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0042] In order to make the purpose, technical solutions and advantages of the present invention clearer, the device proposed in the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the drawings are in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, please refer to the drawings. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical substantive significance. Any structural modification, change in proportional relationship or adjustment of size, without affecting the efficacy and purpose that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention.

[0043] First embodiment:

[0044] like Figure 1 As shown, the method for preparing a mask dust prevention system for extreme ultraviolet lithography comprises the following steps:

[0045] Step S1, preparing a ceramic frame 2.

[0046] Specifically, the preparation method of the ceramic frame 2 is: add the following components in parts by weight in sequence: 1 part of nano-zirconium oxide, 50 parts of zirconium carbonate, 5 parts of boric acid, 5 parts of phosphoric acid, 5 parts of vanadic acid, 10 parts of tungstic acid and 5 parts of molybdic acid, mix them evenly, prepare a ceramic body according to the size, and sinter it in a hot pressing furnace at a sintering temperature of 1000°C and a pressure of 100 MPa. Apply a voltage of 10 V and a pulse current of 50,000 A to the body to obtain the ceramic frame 2.

[0047] Step S2, preparing an organic fluorine polymer film.

[0048] Specifically, amorphous fluororesin films were prepared using a spin coating method. The amorphous fluororesin, a copolymer of perfluorodioxole and tetrafluoroethylene, was prepared with a 10% solution of Chemours Teflon AF 2400. The solution was dripped onto a spin coater disk, the spin speed increased to 3000 rpm, and the film was baked at 80°C for 10 minutes to evaporate the solvent, resulting in a 100 nm thick fluororesin film.

[0049] Step S3: performing film uniformity testing on the organic fluoropolymer film.

[0050] Specifically, a transmittance and haze tester is used to test the transmittance and haze at multiple points on the organic fluoropolymer film. The light source band is 193nm, and the transmittance range is 95.00%±0.15. If it exceeds the tolerance range, it will be scrapped.

[0051] Step S4: bonding the ceramic frame 2 and the organic fluorine polymer film.

[0052] Specifically, a ceramic adhesive is used to bond the ceramic frame 2 to the organic fluoropolymer film. The ceramic adhesive is prepared by sequentially adding the following components by weight: 1 part fluorosilicone resin, 50 parts potassium silicate, 10 parts zirconium oxide, 20 parts aluminum phosphate, and 20 parts calcium borate, and mixing them evenly to obtain a ceramic adhesive. The organic fluoropolymer film is flattened, and the ceramic frame 2 is directly placed upside down on the organic fluoropolymer film. The organic fluoropolymer film is then separated from the substrate. The organic fluoropolymer film can also be transferred together with the support film and then separated. The low surface energy of fluoroplastics makes separation easier.

[0053] Step S5: depositing a catalyst on the surface of the organic fluorine polymer film.

[0054] Specifically, the following steps are included:

[0055] The catalyst solution was prepared as an aerosol using an aerosol generator. The colloidal particles had a diameter of 10 nm and a concentration of 100 ppm and were then deposited on the surface of the organic fluoropolymer film for 20 seconds. The catalyst solution preparation method included the following steps: adding the following components in parts by weight: 1 part perfluorooctadecanoate iron, 200 parts water, 1 part perfluorooctanol, 0.5 part perfluorobutyl ethyl acrylate, 0.5 part perfluorooctyl ethylene, and 0.5 part perfluorobutyl iodide.

[0056] Then, the organic fluoropolymer film was dried in an oven at 80° C. for 2 minutes.

[0057] Step S6: forming the graphene-carbon nanotube composite film 1.

[0058] Specifically, an organic fluoropolymer film with a catalyst deposited on its surface was placed in a furnace chamber, and vacuum was applied, maintaining a vacuum of 90 Pa. The temperature was raised to 3000°C in 60 milliseconds, held for 10 seconds, and then cooled to room temperature at a rate of 100°C / min. The organic fluoropolymer film reacted to form a graphene-carbon nanotube composite film 1 with a thickness of 30 nm.

[0059] Step S7, thinning the graphene-carbon nanotube composite film 1.

[0060] Specifically, the graphene-carbon nanotube composite film 1 is placed in the furnace chamber, and the vacuum is turned on to maintain the vacuum degree at 90Pa.

[0061] Nitrogen and 1% hydrogen were introduced, and the temperature was raised to 500° C. for 30 minutes. The graphene carbon nanotube composite film 1 reacted with the hydrogen and its thickness was reduced to 12 nm.

[0062] Step S8 : bonding the high-temperature resistant rubber buffer layer 3 to the lower end of the ceramic frame 2 .

[0063] Specifically, a high temperature resistant organic adhesive is used to bond the high temperature resistant rubber buffer layer 3 and the ceramic frame 2. The high temperature resistant organic adhesive is SY-26M organic silicone adhesive, and the high temperature resistant rubber buffer layer 3 is made of Tecnoflon NH fluororubber.

[0064] Step S9: The mask dust protection system is installed on an aspirated air pressure pulse meter with the air pressure set to 1 kPa, the pulse frequency to 1 Hz, the temperature to 50°C, and the pulse count to 5000. The total aspirated volume is tested to be 30 μL. If the total aspirated volume L is less than 100 μL, the test is qualified.

[0065] Second embodiment:

[0066] like Figure 1 As shown, the method for preparing a mask dust prevention system for extreme ultraviolet lithography comprises the following steps:

[0067] Step S1, preparing a ceramic frame 2.

[0068] Specifically, the preparation method of the ceramic frame 2 is: add the following components in parts by weight in sequence: 1 part of nano-zirconium oxide, 10 parts of zirconium carbonate, 1 part of boric acid, 1 part of phosphoric acid, 10 parts of vanadic acid, 5 parts of tungstic acid and 1 part of molybdic acid, mix them evenly, prepare a ceramic green body according to the size, use a hot pressing sintering furnace to sinter, the sintering temperature is 1500°C, the pressure is 200MPa, and a voltage of 10V and a pulse current of 50000A are applied to the green body to obtain the ceramic frame 2.

[0069] Step S2, preparing an organic fluorine polymer film.

[0070] Specifically, hexafluoropropylene oxide was used as the front wheel driving gas, and a hot wire chemical vapor deposition method was used to obtain an organic fluorine polymer film with a thickness of 60 nm.

[0071] Step S3: performing film uniformity testing on the organic fluoropolymer film.

[0072] Specifically, a transmittance and haze tester is used to test the transmittance and haze at multiple points on the organic fluoropolymer film. The light source band is between 193nm and the transmittance range is 95.00%±0.15. If it exceeds the tolerance range, it will be scrapped.

[0073] Step S4: bonding the ceramic frame 2 and the organic fluorine polymer film.

[0074] Specifically, a ceramic adhesive is used to bond the ceramic frame 2 to the organic fluoropolymer film. The ceramic adhesive is prepared by adding the following components in parts by weight: 1 part fluorosilicone resin, 10 parts potassium silicate, 10 parts zirconium oxide, 1 part aluminum phosphate, and 10 parts calcium borate, and mixing them uniformly to form a ceramic adhesive. The ceramic frame 2 and the ceramic adhesive are capable of meeting the high-temperature processing conditions of Joule heat flash evaporation.

[0075] Step S5: depositing a catalyst on the surface of the organic fluorine polymer film.

[0076] Specifically, the following steps are included:

[0077] Catalyst solution preparation: Add the following components in order by weight: 1 part perfluorooctadecanoate iron, 200 parts water, 1 part perfluorooctanol, 0.5 part perfluorobutyl ethyl acrylate, 0.5 part perfluorooctyl ethylene, and 0.5 part perfluorobutyl iodide. The catalyst solution is generated by an aerosol generator to form an aerosol with a colloidal particle size of 10 nm and a concentration of 100 ppm. The aerosol is then deposited on the surface of the organic fluoropolymer film for 20 seconds.

[0078] Then, the organic fluoropolymer film was dried in an oven at 80° C. for 2 minutes.

[0079] Step S6: forming the graphene-carbon nanotube composite film 1.

[0080] Specifically, the organic fluoropolymer film with the catalyst deposited on the surface is placed in the furnace chamber, and the vacuum is turned on to maintain the vacuum degree at 25Pa.

[0081] The temperature was raised to 3000° C. in 100 milliseconds, maintained for 5 seconds, and then cooled to room temperature at a cooling rate of 20° C. / min. The organic fluorine polymer film reacted to form a graphene carbon nanotube composite film 1 with a thickness of 20 nm.

[0082] Step S7, thinning the graphene-carbon nanotube composite film 1.

[0083] Specifically, the graphene-carbon nanotube composite film 1 is placed in the furnace chamber, and the vacuum is turned on to maintain the vacuum degree at 25Pa.

[0084] Nitrogen and 0.01% hydrogen were introduced, and the temperature was raised to 1500° C. for 5 minutes. The graphene carbon nanotube composite film 1 reacted with the hydrogen and its thickness was reduced to 12 nm.

[0085] Step S8 : bonding the high-temperature resistant rubber buffer layer 3 to the lower end of the ceramic frame 2 .

[0086] Specifically, a high temperature resistant organic adhesive is used to bond the high temperature resistant rubber buffer layer 3 and the ceramic frame 2. The organic adhesive is a nitrile rubber adhesive, and the high temperature resistant rubber buffer layer 3 is made of silicone rubber.

[0087] Step S9: The mask dust protection system is installed on an aspirated air pressure pulse meter with the air pressure set to 1 kPa, the pulse frequency to 1 Hz, the temperature to 50°C, and the pulse count to 5000. The total aspirated volume is tested to be 30 μL. If the total aspirated volume L is less than 100 μL, the test is qualified.

[0088] First comparative example:

[0089] like Figure 1 As shown, the method for preparing a mask dust prevention system for extreme ultraviolet lithography comprises the following steps:

[0090] Step S1, preparing a ceramic frame 2.

[0091] Specifically, the preparation method of the ceramic frame 2 is: add the following components in parts by weight in sequence: 10 parts of zirconium carbonate, 1 part of boric acid and 1 part of phosphoric acid, mix them evenly, prepare a ceramic body according to the size, and sinter it in a hot pressing furnace at a sintering temperature of 1500°C and a pressure of 200 MPa to obtain the ceramic frame 2.

[0092] Step S2, preparing an organic fluorine polymer film.

[0093] Specifically, hexafluoropropylene oxide was used as the front wheel driving gas, and a hot wire chemical vapor deposition method was used to obtain an organic fluorine polymer film with a thickness of 60 nm.

[0094] Step S3: performing film uniformity testing on the organic fluoropolymer film.

[0095] Specifically, a transmittance and haze tester is used to test the transmittance and haze at multiple points on the organic fluoropolymer film. The light source band is between 193nm and the transmittance range is 95.00%±0.15. If it exceeds the tolerance range, it will be scrapped.

[0096] Step S4: bonding the ceramic frame 2 and the organic fluorine polymer film.

[0097] Specifically, a ceramic adhesive is used to bond the ceramic frame 2 to the organic fluoropolymer film. The ceramic adhesive is prepared by adding the following components in parts by weight: 1 part fluorosilicone resin, 60 parts zirconium oxide, 1 part aluminum phosphate, and 10 parts calcium borate, and mixing them uniformly to obtain a ceramic adhesive. The ceramic frame 2 and the ceramic adhesive are capable of meeting the high-temperature processing conditions of Joule heat flash evaporation.

[0098] Step S5: forming the graphene-carbon nanotube composite film 1.

[0099] Specifically, the organic fluoropolymer film is placed in a furnace chamber, vacuum is turned on, the temperature is raised to 3000° C. in 100 milliseconds, held for 5 seconds, and then cooled to room temperature. The organic fluoropolymer film reacts to form a graphene carbon nanotube composite film 1 with a thickness of 20 nm.

[0100] Step S6, thinning the graphene-carbon nanotube composite film 1.

[0101] Specifically, the graphene-carbon nanotube composite film 1 is placed in the furnace chamber, and the vacuum is turned on to maintain the vacuum degree at 60Pa.

[0102] Nitrogen and 0.01% hydrogen were introduced, and the temperature was raised to 1500° C. for 5 minutes. The graphene carbon nanotube composite film 1 reacted with the hydrogen and its thickness was reduced to 12 nm.

[0103] Step S7 : bonding the high-temperature resistant rubber buffer layer 3 to the lower end of the ceramic frame 2 .

[0104] Specifically, a high temperature resistant organic adhesive is used to bond the high temperature resistant rubber buffer layer 3 and the ceramic frame 2. The high temperature resistant organic adhesive is a nitrile rubber adhesive, and the high temperature resistant rubber buffer layer 3 is made of silicone rubber.

[0105] Step S8: The mask dust protection system is installed on an aspirated air pressure pulse meter with air pressure set to 1 kPa, pulse frequency 1 Hz, temperature 50°C, and pulse number 5000. The total aspirated volume is tested to be 9000 μL. If the total aspirated volume L>100 μL, it is unqualified.

[0106] Test example:

[0107] The mask dust protection systems prepared in the first embodiment, the second embodiment and the comparative example were tested, and the test results are shown in Table 1.

[0108] Table 1

[0109]

[0110] In the first example, the dust-proof system produced had a total air intake volume of 30 μL. The membrane was intact and the strength was acceptable. A scanning electron microscope was used to inspect the ceramic frame 2, which showed no cracks. A 13.5 nm wavelength transmittance meter was used to test the transmittance at 20 locations on the dust-proof system. The maximum transmittance was 92.7%, and the minimum was 92.6%. The transmittances were all above 90%, with the difference within 0.5%. The dust-proof system passed the test.

[0111] In the second example, a dust-proof system was prepared with a total air intake volume of 30 μL. The membrane was intact and the strength was acceptable. A scanning electron microscope was used to inspect the ceramic frame 2, which showed no cracks. A 13.5 nm wavelength transmittance meter was used to test the transmittance at 20 locations on the dust-proof system. The maximum transmittance was 91.3%, and the minimum was 91.1%. The transmittances were all above 90%, with the difference within 0.5%. The dust-proof system passed the test.

[0112] The first comparative example prepared a dust-proof system with a total air intake of 9000 μL, the membrane was damaged, and the strength was unqualified. A scanning electron microscope was used to inspect the ceramic frame 2. The frame had many cracks because the ceramic frame 2 formula did not use toughening and low thermal expansion coefficient components, which led to cracks during the processing. The transmittance of 20 positions of the dust-proof system was tested using a 13.5 nm wavelength transmittance tester. The maximum transmittance was 91.9% and the minimum was 88.5%. There are areas with a transmittance below 90%, and the difference is greater than 0.5%. The dust-proof system is unqualified. Because the catalyst system is not used, the carbon nanotube content is small, the membrane strength is insufficient, and the uniformity of the membrane after thinning is poor, and the membrane transmittance is uneven.

[0113] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0114] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for preparing a mask dust prevention system for extreme ultraviolet lithography, characterized in that: The following steps are involved: preparing a ceramic frame; Prepare organic fluoropolymer films and test their uniformity; Bonding ceramic frames to organic fluoropolymer films; A catalyst is deposited on the surface of an organic fluoropolymer film; the method for preparing the catalyst solution comprises the following steps: The following components are added in parts by weight in sequence: 1 part of fluorine-containing organic acid iron, 100-500 parts of water, 0.5-2 parts of fluorine-containing emulsifier, 0.1-1 part of fluorine-containing leveling agent, 0.1-1 part of fluorine-containing wetting agent, and 0.1-1 part of fluorine-containing atomizer; Graphene carbon nanotube composite film forming; the steps of graphene carbon nanotube composite film forming include: The organic fluoropolymer film with the catalyst deposited on the surface is placed in the furnace chamber, and the vacuum is turned on to maintain the vacuum degree at 10~100Pa; Open the temperature program: the furnace temperature rises from room temperature to 1500~3000℃ within 1~100 milliseconds, and lasts for 1~20 seconds; Cool down to room temperature at a cooling rate of 10~100℃ / min; Thinning of graphene-carbon nanotube composite films; The lower end of the ceramic frame is bonded with a high-temperature resistant rubber buffer layer; Test strength and airtightness.

2. The method for preparing a dust-proof system for an EUV lithography mask according to claim 1, wherein: The steps of preparing the ceramic frame include: The following components are added in parts by weight in sequence: 1-10 parts of nano-zirconium oxide, 10-50 parts of zirconium carbonate, 1-10 parts of boric acid, 1-10 parts of phosphoric acid, 1-10 parts of vanadic acid, 1-10 parts of tungstic acid, and 1-10 parts of molybdic acid, mixed evenly, and a ceramic body is prepared according to the size. The ceramic body is placed in a hot pressing sintering furnace and the program is turned on: the sintering temperature is 1000~1500℃, the pressure is 100~200MPa, a voltage of 2~10V and a pulse current of 1000~50000A are applied to the body to obtain a ceramic frame.

3. The method for preparing a dust-proof system for an EUV lithography mask according to claim 1, wherein: The steps of preparing the organic fluoropolymer film and testing the uniformity include: Prepare an organic fluoropolymer film of any fluorocarbon polymer such as an amorphous fluororesin film, a poly(perfluoroalkyl acrylate) film, polytetrafluoroethylene, a fluoroethylene-propylene copolymer, polyperfluoropropylene, and polytrifluoroethylene by any one of the methods selected from spin coating, turning and stretching, vapor deposition, phase separation, and electrospinning, wherein the thickness of the organic fluoropolymer film is 0.06 to 0.1 μm; The transmittance and haze tester were used to test the transmittance and haze at multiple points on the organic fluoropolymer film. The light source band was 100nm~300nm, and the transmittance range was 95.00%±0.5%. Films that exceeded the tolerance range were scrapped.

4. The method for preparing a dust-proof system for an EUV lithography mask according to claim 1, wherein: A ceramic adhesive is used to bond the ceramic frame and the organic fluoropolymer film. The ceramic adhesive is prepared by sequentially adding the following components in parts by weight: 0.1 to 1 part of fluorosilicone resin, 10 to 50 parts of potassium silicate, 2 to 10 parts of zirconium oxide, 1 to 50 parts of aluminum phosphate, and 1 to 50 parts of calcium borate, and mixing them evenly to obtain a ceramic adhesive.

5. The method for preparing a dust-proof system for an EUV lithography mask according to claim 1, wherein: The step of depositing a catalyst on the surface of the organic fluoropolymer film comprises: The catalyst solution is prepared into aerosol by an aerosol generator, with a colloidal particle size of 5-50 nm and a concentration of 10-200 ppm, and is deposited on the surface of the organic fluoropolymer film; Drying of organic fluoropolymer films.

6. The method for preparing a dust-proof system for an EUV lithography mask according to claim 5, wherein: in, The fluorine-containing organic acid iron is an organic acid iron compound containing at least one fluorine atom replacing a hydrogen atom; the fluorine-containing emulsifier is a mixture of one or more of perfluorohexanol, perfluorooctanol and perfluoroethanol; the fluorine-containing leveling agent is a mixture of one or more of perfluorooctylpropyl acrylate, perfluoroalkylethanol polyoxyethylene ether, perfluorohexylethyltrimethoxysilane, perfluorobutylethyl acrylate, perfluorohexylethyl acrylate, perfluorooctylethyl acrylate, perfluorooctylethyl acrylate, perfluorodecylethyl acrylate and perfluoroalkylethyl acrylate; the fluorine-containing wetting agent is one or more of perfluorohexylethylene, perfluorooctylethylene, perfluorodecylethylene and perfluoroalkylethylene; the fluorine-containing atomizer is a mixture of one or more of pentafluoroiodoethane, perfluorobutyl iodide, perfluorohexyl iodide, perfluorooctyl iodide, perfluoroalkyl iodide, perfluorobutylethyl iodide, perfluorohexylethyl iodide, perfluorooctylethyl iodide and perfluoroalkyl iodide.

7. The method for preparing a dust-proof system for an EUV lithography mask according to claim 1, wherein: The step of thinning the graphene carbon nanotube composite film comprises: The graphene carbon nanotube composite film is placed in the furnace chamber, and the vacuum is turned on to maintain the vacuum degree at 10~100Pa; Introduce hydrogen and maintain the hydrogen concentration at 0.01%~1%; Raise the temperature to 500~1500℃ and keep it for 1~30 minutes; Cool to room temperature.

8. The method for preparing a dust prevention system for an EUV lithography mask according to claim 1, wherein: The high-temperature resistant rubber buffer layer is bonded to the lower end of the ceramic frame by using a high-temperature resistant organic adhesive.

9. The method for preparing a dust prevention system for an EUV lithography mask according to claim 1, wherein: The steps of testing strength and air tightness include: installing the mask dustproof system after bonding the high-temperature resistant rubber buffer layer on an inhalation air pressure pulse instrument, setting the air pressure to 1KPa, the pulse frequency to 1Hz, the temperature to 30~80℃, and the number of pulses to 5000 times; testing the total inhalation volume L, and passing the test when the total inhalation volume L<100μL.

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