A method for manufacturing a photolithography mask based on a nanoparticle monolayer array

Abstract

A method for manufacturing photolithographic masks based on nanoparticle arrays is disclosed. This method utilizes inkjet printing to create a controllable array of water droplets. Nanoparticle arrays of different diameters are then sprayed onto the surface of the water droplets. The nanoparticle dispersion is immiscible with the water droplets, forming a nanoparticle monolayer film on the droplet surface. After heating and drying, a nanoparticle monolayer array is formed, which is then transferred to a flexible transparent substrate. By controlling the nanoparticle colloidal material and diameter printed on the surface of water droplets at different locations, photolithographic masks based on nanoparticle monolayer arrays of various sizes can be formed to manufacture complex micro / nano structure arrays. This invention overcomes the limitation of nanoparticle array masks, which can only manufacture single-morphological structures, by using inkjet printing to locally manufacture combinations of nanoparticle monolayer arrays of different diameters. This results in a simple, efficient, and controllable nanoparticle monolayer array manufacturing technology.

Description

Technical Field

[0001] This invention belongs to the field of micro-nano structure photolithography technology, specifically relating to a method for manufacturing photolithographic masks based on a single-layer array of nanoparticles. Background Technology

[0002] Arrayed nanostructures are widely used in the fabrication of functional devices such as data storage, photovoltaics, energy storage, piezoelectrics, and sensors. Fabrication methods for nanoarray structures include laser processing, electron beam etching, focused ion beam etching, microcontact imprinting, and photolithography. Among these, photolithography is the most widely used due to its high manufacturing efficiency, good stability, and low cost. In photolithography, incident light is projected onto photoresist using a mask, and after development, nanostructures are formed on the photoresist. However, the constraint of the mask's projection of incident light makes it difficult to fabricate nanoarray structures with three-dimensional morphology.

[0003] Scientists have developed a photolithography technique using a monolayer array of dielectric nanoparticles as a mask, leveraging the light field manipulation capabilities of nanoparticles (ACS Appl. Mater. Interfaces 2014, 6, 20837-20841, doi.org / 10.1021 / am505221g). This technique enables the direct fabrication of complex three-dimensional nanostructures from photoresist layers. However, current methods for fabricating nanoparticle masks are limited to large-area monolayer arrays of single nanoparticles, making it difficult to fabricate complex photolithography masks composed of combinations of multiple nanoparticle monolayer arrays. This restricts the widespread application of nanoparticle monolayer array masks in the fabrication of nanodevices. Therefore, there is a need to develop a simple and controllable method for fabricating complex masks that can achieve localized arrangements of multiple nanoparticle monolayer arrays, facilitating the efficient fabrication of three-dimensional nanoarray structures. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention aims to provide a photolithographic mask manufacturing method based on a nanoparticle monolayer array. By using inkjet printing to localize the fabrication of nanoparticle monolayer array combinations of different diameters, the invention breaks through the limitation that nanoparticle array masks can only manufacture single morphological structures, thus forming a simple, efficient, and controllable nanoparticle monolayer array manufacturing technology.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for manufacturing a photolithographic mask based on a nanoparticle array is disclosed. This method utilizes inkjet printing to create a controllable array of water droplets. Nanoparticle arrays of different diameters are then sprayed onto the surface of the water droplets. The nanoparticle dispersion is immiscible with the water droplets, forming a nanoparticle monolayer film on the droplet surface. After heating and drying, a nanoparticle monolayer array is formed. This nanoparticle monolayer array is then transferred to a flexible transparent substrate. By controlling the nanoparticle colloidal material and diameter printed on the surface of water droplets at different locations, a photolithographic mask based on a nanoparticle monolayer array of various sizes can be formed to manufacture complex micro / nano structure arrays.

[0007] A method for fabricating a photolithographic mask based on a nanoparticle array includes the following steps:

[0008] 1) Preparation of dielectric nanoparticle colloidal ink;

[0009] 2) Clean the substrate thoroughly and perform hydrophobic treatment on the substrate surface;

[0010] 3) Perform hydrophilic treatment on the array patterned area on the hydrophobic surface of the substrate;

[0011] 4) Using ultrapure water as printing ink, water droplets are printed on the hydrophilic array pattern area on the substrate surface using an inkjet printer.

[0012] 5) Using the dielectric nanoparticle colloidal ink prepared in step 1) as the printing ink, inkjet print the dielectric nanoparticle colloidal ink on the surface of the water droplet to form a nanoparticle monolayer film on the surface of the water droplet.

[0013] 6) Heat the substrate until the water droplets and the dispersion in the dielectric nanoparticle colloidal ink completely evaporate to form a nanoparticle monolayer array;

[0014] 7) Transfer the nanoparticle monolayer array to the surface of a flexible thin film to form a photolithographic mask based on the nanoparticle monolayer array.

[0015] In step 1), the nanoparticles are made of materials such as silica, polystyrene, and polymethyl methacrylate. The nanoparticles are spherical or have a spherical core-shell structure. The dispersion of the particle colloid is made of materials such as n-butanol, cyclohexane, n-hexane, benzene, toluene, n-heptane, and isooctane. The diameter of the nanoparticles is 300–1200 nm, and the particle mass fraction is 8–20%.

[0016] In step 2), the substrate material is a smooth glass, metal, or plastic polymer, and the contact angle θ1 of the hydrophobically treated substrate surface satisfies θ1≥100°.

[0017] In step 3), the contact angle θ2 of the hydrophilically treated array pattern area surface satisfies θ2≤60°;

[0018] In step 4) of the water droplet printing process, the area S after the water droplet fills the hydrophilic array pattern area unit is ≥ 5mm × 5mm.

[0019] In step 5), the inkjet printer's multiple printheads spray dielectric nanoparticle colloidal inks of different materials and diameters onto the surface of water droplets at different positions in the water droplet array. The ratio K of the total area of ​​the nanoparticle monolayer film to the bottom area of ​​the droplets satisfies 0.8≤K≤1.2.

[0020] In step 6), the substrate is heated using a hot plate for 2 to 6 minutes, and the temperature of the hot plate is 50 to 90°C.

[0021] In step 7), polydimethylsiloxane (PDMS) is coated on the surface of the nanoparticle monolayer array and cured to form a thin film with a thickness of 3-8 mm as a uniform and stable transparent flexible substrate. The nanoparticle monolayer array is then transferred into the PDMS thin film to form a photomask.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] Conventional photolithography processes can only replicate the quasi-three-dimensional structure of the mask, making it difficult to fabricate three-dimensional structures with structural variations perpendicular to the mask direction. This invention utilizes inkjet printing to locally fabricate multi-sized monolayer arrays of nanoparticles, and then transfers these arrays to a flexible transparent substrate to form a photolithography mask. This nanoparticle monolayer array mask can control the energy distribution of the transmitted light field, enabling the direct fabrication of complex three-dimensional structures within the photoresist layer. Furthermore, it holds promise for creating resolvable photolithographic structures that can overcome the diffraction limit. In addition, because the nanoparticle monolayer array photolithography mask is based on a flexible thin film, it easily forms a tight bond with the photoresist surface, especially on micro-curved substrates, improving the uniformity and stability of the photolithography process. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the smooth and flat substrate of the present invention.

[0025] Figure 2 This is a schematic diagram of the hydrophobic treatment of the substrate surface according to the present invention.

[0026] Figure 3 This is a schematic diagram of the substrate for the hydrophilic surface patterning treatment of the present invention.

[0027] Figure 4 This is a schematic diagram of the water droplet array printed in the hydrophilic region of the substrate of the present invention.

[0028] Figure 5 This is a schematic diagram of the process of aligning and printing nanoparticle colloids on the surface of a water droplet according to the present invention.

[0029] Figure 6This is a schematic diagram illustrating the formation of different nanoparticle monolayer film arrays on the surface of water droplets according to the present invention.

[0030] Figure 7 This is a schematic diagram of a localized multi-size nanoparticle monolayer array according to the present invention.

[0031] Figure 8 This is a schematic diagram of the flexible mask based on a single-layer array of nanoparticles according to the present invention.

[0032] Figure 9 The electric field distribution on the surface of an EPG533 photoresist substrate after incident 365nm ultraviolet light passes through a 400nm diameter polystyrene spherical particle array mask.

[0033] Figure 10 This is a photolithographic structure of an incident 365nm ultraviolet light passing through a 400nm diameter polystyrene spherical particle array mask on an EPG533 photoresist layer. Detailed Implementation

[0034] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] A method for fabricating a photolithographic mask based on a nanoparticle array includes the following steps:

[0036] 1) Select polystyrene spherical particles with a diameter of 400 nm and disperse them in n-butanol at a mass fraction of 11% to form a uniform and stable nanoparticle colloidal ink.

[0037] 2)Reference Figure 1 Using a 1mm thick glass slide as substrate 1, the slide was ultrasonically cleaned sequentially with acetone, ethanol, and deionized water, dried with nitrogen, and then dried in a 150℃ forced-air drying oven for 1 hour; (Refer to...) Figure 2 A C4F8 film was deposited on the surface of substrate 1 using plasma chemical deposition to obtain hydrophobic surface 2. The contact angle θ1 of the hydrophobically treated substrate surface is 128°.

[0038] 3)Reference Figure 3 A mask is covered on the hydrophobic surface 2, and then a hydrophilic array pattern region 3 is created on the hydrophobic surface 2 using an oxygen plasma cleaner; the surface contact angle θ2 of the hydrophilic array pattern region 3 is 50°.

[0039] 4)Reference Figure 4Using ultrapure water as printing ink, water droplets are sequentially printed in the hydrophilic array pattern area 3 using the printhead 4 of the inkjet printer to form a water droplet array 5; the water droplets cover an area S = 7mm × 7mm within the unit of the hydrophilic array pattern area 3.

[0040] 5)Reference Figure 5 , Figure 6 Using the nanoparticle colloidal ink prepared in step 1) as the printing ink, nanoparticles 6 and 7 of different materials and diameters are aligned and printed on the surface of the water droplet array 5 to form a nanoparticle monolayer film 8 on the surface of the water droplet. The ratio of the total area of ​​the nanoparticle monolayer film 8 to the bottom area of ​​the droplet is K = 1.

[0041] 6)Reference Figure 7 The substrate 1 is heated by a hot plate for 5 minutes at a temperature of 80°C. After heating, the nanoparticle monolayer film 8 yields a variety of different nanoparticle monolayer arrays 9.

[0042] 7)Reference Figure 8 Multiple different nanoparticle monolayer arrays 9 were transferred to the surface of polydimethylsiloxane (PDMS) to obtain a 5 mm thick mask 10 based on nanoparticle arrays.

[0043] The electric field distribution calculated by FDTD simulation of the transmission field of the polystyrene particle array in this embodiment is as follows: Figure 9 As shown, a thermally enhanced electric field region, up to 10 times stronger, can be formed in the photoresist layer at the bottom of the particle array. After exposure and development, the resulting image is obtained from the photoresist layer. Figure 10 The spatial three-dimensional array structure shown.

[0044] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for fabricating a photolithographic mask based on a nanoparticle array, characterized in that: By using inkjet printing to controllable water droplet arrays, nanoparticle arrays of different diameters are sprayed onto the surface of the water droplet arrays. The nanoparticle dispersion is immiscible with the water droplets, forming a nanoparticle monolayer film on the water droplet surface. After heating and drying, a nanoparticle monolayer array is formed, and then the nanoparticle monolayer array is transferred to a flexible transparent substrate. By controlling the nanoparticle colloidal material and diameter of the inkjet-printed water droplet surface at different positions, a photolithographic mask based on a nanoparticle monolayer array can be formed to manufacture complex micro-nano structure arrays of multiple sizes. The method for manufacturing a photolithographic mask based on a nanoparticle array includes the following steps: 1) Preparation of dielectric nanoparticle colloidal ink; 2) Clean the substrate thoroughly and perform hydrophobic treatment on the substrate surface; 3) Cover the hydrophobic surface of the substrate with a mask and perform hydrophilic treatment to form a hydrophilic array pattern region; 4) Using ultrapure water as printing ink, water droplets are sequentially printed on the hydrophilic array pattern area on the substrate surface using an inkjet printer to form a water droplet array; 5) Using the dielectric nanoparticle colloidal ink prepared in step 1) as the printing ink, inkjet print the dielectric nanoparticle colloidal ink on the surface of the water droplet to form a nanoparticle monolayer film on the surface of the water droplet. 6) Heat the substrate until the water droplets and the dispersion in the dielectric nanoparticle colloidal ink completely evaporate, forming a nanoparticle monolayer array; 7) Transfer the nanoparticle monolayer array to the surface of a flexible thin film to form a photolithographic mask based on the nanoparticle monolayer array.

2. The method according to claim 1, characterized in that: In step 1), the nanoparticles are made of silica, polystyrene, or polymethyl methacrylate. The nanoparticles are spherical or have a spherical core-shell structure. The dispersion of the particle colloid is made of n-butanol, cyclohexane, n-hexane, benzene, toluene, n-heptane, or isooctane. The diameter of the nanoparticles is 300-1200 nm, and the particle mass fraction is 8-20%.

3. The method according to claim 1, characterized in that: In step 2), the substrate material is glass, metal, or plastic polymer, and the contact angle of the hydrophobically treated substrate surface is... satisfy ≥100°.

4. The method according to claim 1, characterized in that: The contact angle of the surface of the hydrophilically treated array patterned region in step 3) satisfy ≤60°.

5. The method according to claim 1, characterized in that: Step 4) The area after the water droplets fill the hydrophilic array pattern area unit during water droplet printing. S ≥5mm×5mm.

6. The method according to claim 1, characterized in that: In step 5), the inkjet printer's multiple printheads spray dielectric nanoparticle colloidal inks of different materials and diameters onto the surface of water droplets at different positions in the water droplet array. The ratio of the total area of ​​the nanoparticle monolayer film on the water droplet surface to the bottom area of ​​the water droplet... K Satisfying 0.8≤ K ≤1.

2.

7. The method according to claim 1, characterized in that: In step 6), the substrate is heated using a hot plate for 2-6 minutes, and the temperature of the hot plate is 50-90 °C.

8. The method according to claim 1, characterized in that: In step 7), polydimethylsiloxane (PDMS) is coated on the surface of the nanoparticle monolayer array and cured to form a thin film with a thickness of 3-8 mm as a transparent flexible substrate. The nanoparticle monolayer array is then transferred into the PDMS film to form a photomask.

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