Fabrication method of high-resolution display based on metal nanocolumn structure

Abstract

The present invention discloses a method for fabricating a high-resolution display based on a metal nanocolumn structure. The method includes the steps of: spin-coating a photoresist on a flat and smooth glass surface, and fabricating a periodically ordered ring structure by electron beam lithography; performing reactive ion etching on the ring structure to obtain an annular cavity structure, adding NOA into the annular cavity structure and then peeling it off to obtain periodic cylinders; coating an imprinting adhesive on the periodic cylinders, and tearing it off after the nanoimprinting adhesive is cured to obtain a periodic annular cavity structure on the imprinting adhesive; heating the periodic annular cavity structure, which will change the curvature of the upper edge of the annular cavity structure and the curvature of the cylinders, and generating different deformations at the edges by heating for different times, and then depositing an aluminum film on the periodic annular cavity structure; exciting surface plasmons on the surface of the periodic annular cavity structure, so as to display different colors at different degrees of deformation. The high-resolution display based on the metal annular cavity structure of the present invention improves the pixel resolution and solves the problems of color dye pollution and the size of dyed pixels.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a high-resolution display based on a metal nanocylinder structure, belonging to the technical field of optical displays. Background Art

[0002] Insects, butterflies, etc. in nature generate colors mainly through the interference of thin films or multilayer structures, grating diffraction, photonic crystals, light scattering and other effects. This method of generating colors has given rise to the field of structural color displays. However, for the further development of structural colors, an important challenge is the limitation of the optical diffraction limit. The development of micro-nano metal structure preparation technology provides a new way to break through the diffraction limit and achieve high resolution. The interaction between metal micro-nano structures and light can generate surface plasmon resonances (SPRs). SPRs can manipulate the polarization, phase and intensity of light, and its secondary diffraction localization effect can break through the diffraction limit, which enables metal micro-nano structures to have the ability to generate ultra-high resolution colors.

[0003] Traditional structural color displays have several limitations: they can only achieve static structural colors, lack the process for large-area preparation of nano-structures, can only achieve a single pixel with a narrow color range, and have low resolution, etc. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for manufacturing a high-resolution display based on a metal nanocylinder structure to solve the defects of the prior art.

[0005] A method for manufacturing a high-resolution display based on a metal nanocylinder structure, the method comprising the steps of:

[0006] Spin-coat a photoresist on a flat and smooth glass surface, and use electron beam lithography to fabricate a periodically ordered ring structure;

[0007] Perform reactive ion etching on the ring structure to obtain an annular cavity structure, add NOA into the annular cavity structure and then peel it off to obtain periodic cylinders;

[0008] Coat a nanoimprint resist on the periodic cylinders, and after the nanoimprint resist is cured, tear it off to obtain a periodic annular cavity structure on the imprint resist;

[0009] Heat the periodic annular cavity structure, and then deposit an aluminum film on the periodic annular cavity structure;

[0010] Excite the surface plasmon of the periodic annular cavity structure to display different colors.

[0011] Further, the method for heating the periodic annular cavity structure includes: heating the edge of the periodic annular cavity structure using a carbon dioxide laser.

[0012] Furthermore, the method for aluminizing the periodic ring cavity structure includes: depositing a layer of aluminum film on the surface of the heated imprinted glue using the magnetron sputtering method.

[0013] Furthermore, the photoresist is PMMA-A4 positive photoresist.

[0014] Furthermore, the photoresist on the surface of the ring structure is etched using RIE, and CHF3 is selected as the etching gas.

[0015] Furthermore, the method for removing the photoresist on the glass surface includes: removing the photoresist on the glass surface using ozone deionized water.

[0016] Furthermore, when removing the photoresist, ozone deionized water obtained by dissolving ozone in deionized water is used and atomized and sprayed on the glass surface.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: It demonstrates the advantages of the metal micro-nano structure display, such as vivid colors, high contrast, and insensitivity to external environmental changes. The high-resolution display based on the metal ring cavity structure improves the pixel resolution, solves the problems of color dye pollution, the size of the dyed pixels, and the durability under high temperature or ultraviolet irradiation. The metamaterial structural color can perfectly solve these problems, and it has important applications in surface plasmon ultra-high pixel imaging, surface plasmon liquid crystal display, surface plasmon luminescence, and structural color information coding in recent years. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1(a)(b) is a schematic diagram of magnetron sputtering a layer of aluminum on the structure of FIG. 10;

[0019] Figure 2 is a schematic diagram of coating photoresist on the smooth and flat silicon wafer surface of the present invention;

[0020] FIG. 3 is a schematic diagram of Figure 2 for electron beam exposure;

[0021] Figure 4 is a schematic diagram of the silicon wafer after CHF3 reactive ion etching using the ring structure obtained in FIG. 3 as a mask;

[0022] Figure 5 is Figure 4 a schematic diagram after removing the photoresist on the structure;

[0023] Figure 6 is Figure 5 a schematic diagram after coating NOA glue;

[0024] Figure 7 is Figure 6 a schematic diagram after tearing off the NOA glue of

[0025] Figure 8 It is a schematic diagram of spin - coating a nano - imprinting resist on a structure; Figure 7 It is a schematic diagram of spin - coating a nano - imprinting resist on a structure;

[0026] Figure 9 It is a schematic diagram after peeling off the imprinting resist of Figure 8 It is a schematic diagram after peeling off the imprinting resist of

[0027] Figures 10(a), (b), and (c) are respectively schematic diagrams of locally heating Figure 9 using an AFM probe for different times;

[0028] Figure 11 It is a manufacturing flow chart of the present invention. Detailed implementation manners

[0029] To make the technical means, creative features, achieved purposes, and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific implementation manners.

[0030] As shown in Figures 1 - 10, a manufacturing method of a high - resolution display based on a metal nanocolumn structure is disclosed, and its cross - sectional schematic diagram is shown in Figures 1(a) and (b). The structure of this display mainly includes metallic aluminum and a periodically ordered ring - cavity structure.

[0031] The specific manufacturing method includes the steps:

[0032] Spin - coat a layer of PMMA positive photoresist on a smooth glass surface, then perform electron - beam exposure to obtain a periodically ordered ring structure, and then use the RIE etching method to introduce gas to etch the periodically - hole structure formed on the silicon wafer, etch the silicon wafer surface not covered by the photoresist, obtain a periodically ordered ring - cavity structure on the glass surface, then use ozone deionized water to remove the photoresist on the glass surface, then drop NOA glue on the glass surface, and after the NOA glue is cured by ultraviolet light, separate it from the glass surface to obtain a cylindrical micro - nano structure on the NOA glue plane. After that, spin - coat a layer of nano - imprinting resist on the NOA glue, and after the nano - imprinting resist is cured, peel it off to obtain the ring - cavity structure on the imprinting resist;

[0033] Finally, after heating the edges of the ring - cavity in different regions using a carbon dioxide laser for different times, use magnetron sputtering to deposit a layer of aluminum film on the surface of the thermosetting glue to obtain an aluminum ring - cavity structure, and thus obtain different structural - color high - resolution displays; it should be noted that when removing the photoresist, ozone deionized water obtained by dissolving ozone in deionized water is used, and it is atomized and sprayed on the silicon wafer surface.

[0034] The specific heating method includes: using a carbon dioxide laser to heat the nanocolumns, changing the thickness of metallic aluminum, and changing the micro - nano structure.

[0035] The preparation flow chart of the metal ring cavity structure of the present invention is shown in Figure 1-10;

[0036] a) Take a small piece of silicon with a size of 1.5×1.5, ultrasonically clean it in ethanol, acetone, and deionized water for 15 minutes respectively, and then process it with a cleaning machine for 10 minutes.

[0037] b) Pre-bake the silicon wafer on a hot plate at 180 °C for 90 s. After pre-baking, spin-coat a layer of photoresist on the silicon wafer with a thickness of 200 nm, as Figure 2 shown;

[0038] c) Use an electron beam exposure system with a beam current of 100 μA and an applied voltage of 50 kV;

[0039] d) Develop using MIBK:IPA = 1:3 for 90 s; fix using IPA for 30 s. After the nanopore pattern is formed, as shown in Figure 3; dissolve ozone in deionized water to form ozone deionized water, atomize it and spray it on the surface of the silicon wafer to obtain a periodic nanopore array on the silicon wafer surface. As Figure 5 shown;

[0040] e) Using the nanopore array obtained in step d) as a mask, etch the surface of the uncovered silicon wafer with a reactive ion etcher with a radio frequency power of 300 W, a CHF3 flux of 40 sccm, a gas pressure of 5 Pa, and an etching time of 40 s. The etching depth is about 300 nm, as Figure 4 shown;

[0041] f) For the structure obtained in step e), dissolve ozone in deionized water to form ozone deionized water, atomize it and spray it on the surface of the silicon wafer to obtain a periodic nanopore array on the silicon wafer surface. As Figure 5 shown;

[0042] g) Coat a layer of NOA glue on the structure of step f) and cure it under ultraviolet light, as Figure 6 shown;

[0043] h) Dip a little industrial alcohol on the NOA glue in step g) to transfer the nanostructure on the NOA glue, as Figure 7 shown;

[0044] i) Spin-coat a layer of nanoimprint glue on the structure obtained in step h), as Figure 8 shown;

[0045] j) Cure the structure obtained in step i) and then tear off the nanoimprint glue, as Figure 9 shown;

[0046] K) For the structure obtained in step j), use a carbon dioxide laser to locally heat the nanocolumns for different times, as shown in Figures 10(a), (b), and (c) respectively;

[0047] l) Deposit a layer of aluminum with a thickness of about 100 nm on the structure obtained in step k) by magnetron sputtering, as shown in Figure 1.

[0048] In this embodiment, an electron beam lithography method is used to prepare a ring array as an etching mask. The photoresist used is PMMA-A4 positive photoresist, with a thickness of 200 nm, a circular hole diameter of 100 nm, and a spacing of about 50 nm.

[0049] In this embodiment, NOA glue is coated on the etched periodic nanohole array, and the nano-hollow column structure is obtained by tearing it off after the NOA glue is cured.

[0050] Furthermore, a layer of nanoimprinting glue is spin-coated on the nano-hollow column structure on the NOA glue, and the ring cavity structure is obtained by tearing it off after the imprinting glue is cured.

[0051] Traditional optical displays have problems such as being susceptible to interference in transmitted signals and distortion when viewed from different angles. Compared with them, the metal micro-nano structure display demonstrates the advantages of vivid colors, high contrast, and insensitivity to external environmental changes. The high-resolution display based on the metal ring cavity structure improves the pixel resolution, solves the problems of color dye pollution, the size of dyed pixels, and the durability under high temperature or ultraviolet irradiation. All these problems can be perfectly solved by the structural color of metamaterials. In recent years, it has important applications in surface plasmon ultra-high pixel imaging, surface plasmon liquid crystal display, surface plasmon luminescence, and structural color information encoding.

[0052] Main working principle: The present invention is based on the fact that light will excite the metal micro-nano structure to generate surface plasmon structural color. By changing the shape and periodic arrangement of the metal nanocolumn structure, the resonance frequency of the excited plasmon can be regulated to achieve different colors. By controlling the heating time, the curvature of the nanocolumn and the curvature of the upper edge are changed to generate deformation. After plating with metal, different colors will be produced according to different deformations, and the dip of the reflection spectrum will appear at different wavelengths, realizing the absorption of light in different wavelength bands. The reflected bands can display different colors, and different structural colors can be observed from an optical microscope, thereby realizing a high-resolution display.

[0053] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and deformations can still be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.

Claims

1. A method for fabricating a high-resolution display based on a metal nanocylinder structure, characterized in that, the method comprises the steps of: spin-coating a photoresist on a smooth glass surface and fabricating a periodically ordered ring structure by electron beam lithography; performing reactive ion etching on the ring structure to obtain an annular cavity structure, adding NOA into the annular cavity structure and then peeling it off to obtain periodic cylinders; coating a nanoimprint resist on the periodic cylinders, and peeling it off after the nanoimprint resist is cured to obtain a periodic annular cavity structure on the imprint resist; heating the periodic annular cavity structures in different regions for different times, and then depositing an aluminum film on the periodic annular cavity structures; exciting surface plasmons on the surface of the periodic annular cavity structures to display different colors.

2. The method for fabricating a high-resolution display based on a metal nanocylinder structure according to claim 1, characterized in that, the method for heating the periodic annular cavity structures comprises: heating at the edge of the periodic annular cavity structures using a carbon dioxide laser.

3. The method for fabricating a high-resolution display based on a metal nanocylinder structure according to claim 1, characterized in that, the method for depositing an aluminum film on the periodic annular cavity structures comprises: depositing an aluminum film on the surface of the heated imprint resist using a magnetron sputtering method.

4. The method for fabricating a high-resolution display based on a metal nanocylinder structure according to claim 1, characterized in that, the photoresist is a PMMA-A4 positive photoresist.

5. The method for fabricating a high-resolution display based on a metal nanocylinder structure according to claim 1, characterized in that, Use RIE etching on the photoresist on the surface of the ring structure, and select as the etching gas.

6. The method for fabricating a high-resolution display based on a metal nanocylinder structure according to claim 1, characterized in that, the method for removing the photoresist on the glass surface comprises: removing the photoresist on the glass surface using ozone deionized water.

7. The method for fabricating a high-resolution display based on a metal nanocylinder structure according to claim 6, characterized in that, when removing the photoresist, ozone deionized water obtained by dissolving ozone in deionized water is used and atomized and then sprayed on the glass surface.

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