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NL2039587A - A method for fabricating a nanolens array - Google Patents

A method for fabricating a nanolens array Download PDF

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Publication number
NL2039587A
NL2039587A NL2039587A NL2039587A NL2039587A NL 2039587 A NL2039587 A NL 2039587A NL 2039587 A NL2039587 A NL 2039587A NL 2039587 A NL2039587 A NL 2039587A NL 2039587 A NL2039587 A NL 2039587A
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NL
Netherlands
Prior art keywords
grayscale
electron beam
nanolens
array
nanolens array
Prior art date
Application number
NL2039587A
Other languages
Dutch (nl)
Inventor
Xia Liangping
Yang Zengbao
Du Chunlei
Dang Suihu
Zhang Man
Tu Hong
Wang Shuai
Lan Jingtian
Original Assignee
Univ Yangtze Normal
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Univ Yangtze Normal filed Critical Univ Yangtze Normal
Publication of NL2039587A publication Critical patent/NL2039587A/en

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    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00Simple or compound lenses
    • G02B3/0006Arrays
    • G02B3/0012Arrays characterised by the manufacturing method
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00Simple or compound lenses
    • G02B3/0006Arrays
    • G02B3/0037Arrays characterized by the distribution or form of lenses
    • G02B3/0056Arrays characterized by the distribution or form of lenses arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Electron Beam Exposure (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)

Abstract

The invention discloses a method for fabricating a nanolens array, comprising the following steps: Sl: Sequentially spin-coating thermoplastic adhesive and electron beam photoresist on a substrate. SZ: Processing the electron beam photoresist into nanoscale sub-aperture grayscale structures. S3: Transferring the grayscale structures from the electron beam photoresist onto the thermoplastic adhesive. S4: Melting the grayscale structures on the thermoplastic adhesive to form a nanolens array with continuous surface features. By adopting the technical solution of the invention, the problem of hi gh- lO precision surface profile processing for nanolens arrays is effectively resolved.

Description

A method for fabricating a nanolens array
TECHNICAL FIELD
This invention belongs to the field of optical lens technology, particularly relating to a method for fabricating a nanolens array.
BACKGROUND
Optical lenses are the most fundamental components of the majority of optical systems. With the development of miniaturization and chip-based technologies, the demand for miniaturized and integrated optical lenses has grown significantly. For instance, microlens arrays have found wide applications in fields such as digital optical communication coupling, collimation, industrial laser beam shaping, semiconductor shaping, flat-panel displays, and miniature cameras. These applications have driven the miniaturization and integration of modern optical systems.
However, existing fabrication technologies for microlens arrays can only achieve sub-apertures at the micron scale, making it difficult to break through to the nanoscale.
This limitation hinders the further chip-level development of optical lenses.
SUMMARY
The technical problem to be solved by the present invention is to provide a method for manufacturing a nanolens array, addressing the issue of high-precision surface shape processing of nanolens arrays.
To achieve the above objective, the present invention adopts the following technical solution:
A method for producing a nanolens array, comprising the following steps:
Step S1: Spin-coat a layer of hot-melt adhesive and electron beam (e-beam) resist on a substrate sequentially; wherein the substrate is a silicon wafer, glass, or an optical lens.
Step S2: Process the e-beam resist into a grayscale structure with sub-nanometer aperture at the nanoscale.
Step S3: Transfer the grayscale structure from the e-beam resist to the hot-melt adhesive.
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Step S4: Melt the grayscale structure on the hot-melt adhesive to form a nanolens array with continuous surface shape features.
As a preferred embodiment, Step S2 uses e-beam grayscale exposure technology to process the e-beam resist into a grayscale structure with sub-nanometer aperture at the nanoscale.
As a preferred embodiment, Step S3 uses dry etching technology to transfer the grayscale structure from the e-beam resist to the hot-melt adhesive.
As a preferred embodiment, Step S4 uses a hot-melt process to melt the grayscale structure on the hot-melt adhesive to form a nanolens array with continuous surface shape features.
As a preferred embodiment, the surface shape of each unit of the nanolens array is a smooth optical surface shape with a continuous three-dimensional distribution within a single sub-nanometer aperture.
As a preferred embodiment, the distribution of the continuous three-dimensional surface shape of the nanolens array’s sub-aperture units is controlled by the distribution of the e-beam grayscale exposure.
As a preferred embodiment, the substrate is a silicon wafer, glass, or an optical lens.
As a preferred embodiment, the dry etching is oxygen plasma etching.
The present invention combines e-beam grayscale exposure, dry etching transfer, and hot-melt processes to achieve nanoscale sub-apertures for the nanolens array, with controllable optical surface shape precision. Compared to traditional micro-optical lens arrays and their manufacturing methods, the present invention reduces the sub-aperture scale of the optical lens array to the nanoscale, and the lens surface shape precision can be precisely controlled by e-beam grayscale exposure.
BRIEF DESCRIPTION OF THE FIGURES
In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without creative work.
Figure 1 is a flow chart of the method for making a nano lens array in an embodiment of the present invention;
Figure 2 is a schematic diagram of the distribution of electron beam grayscale exposure in a single sub-aperture in an embodiment of the present invention, wherein different rings represent different electron beam exposure doses, and the numbers in the rings represent the ratio of the exposure doses in the ring;
Figure 3 is a schematic diagram of a cross-section of a unit structure after electron beam grayscale exposure in an embodiment of the present invention, wherein 21 is a supporting substrate, 22 is hot melt adhesive, 23 is a grayscale structure formed after electron beam adhesive exposure, and 24 is a continuous surface shape of the nano lens unit to be processed,
Figure 4 is a schematic diagram of a cross-section of a unit structure on hot melt adhesive after dry transfer in an embodiment of the present invention, wherein 32 is
Grayscale structure transferred from electron beam glue to hot melt glue after etching;
Figure 5 is a schematic cross-sectional view of the structure of the nano lens unit after hot melting according to an embodiment of the present invention, wherein 42 is the smooth surface of the continuous surface nano lens obtained after hot melting;
Figure 6 is a three-dimensional structure diagram of the nano lens array arranged in a quadrilateral manner after electron beam grayscale exposure according to an embodiment of the present invention;
Figure 7 is a three-dimensional structure diagram of the nano lens array arranged in a quadrilateral manner after hot melting according to an embodiment of the present invention,
Figure 8 1s a three-dimensional structure diagram of the nano lens array arranged in a hexagonal manner after electron beam grayscale exposure according to an embodiment of the present invention;
Figure 9 is a three-dimensional structure diagram of the nano lens array arranged in a hexagonal manner after hot melting according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail in combination with the drawings and specific implementation methods.
Embodiment 1
As shown in Figure 1, the embodiment of the present invention provides a method for manufacturing a nanolens array, which includes the following steps:
Step S1: Spin-coat a layer of hot-melt adhesive and electron beam (e-beam) resist sequentially on the substrate; wherein the substrate is a silicon water, glass, or optical lens.
Step S2: Process the e-beam resist into a grayscale structure with sub-nanometer apertures at the nanoscale.
Step S3: Transfer the grayscale structure from the e-beam resist to the hot-melt adhesive.
Step S4: Melt the grayscale structure on the hot-melt adhesive to form a nanolens array with continuous surface shape features; wherein the nanolens array consists of lenses with sub-aperture sizes at the nanoscale. The surface shape of each unit of the nanolens array is a smooth optical surface with a continuous three-dimensional distribution within a single sub-nanometer aperture.
As one embodiment of the present invention, Step S2 uses an electron beam exposure system. Silicon is preferably used as the supporting substrate, as shown in
Figure 3 (21). Hot-melt adhesive AZ1500 is spin-coated on the polished surface of the silicon substrate using a spin-coating process, with a thickness of 1-2 microns, preferably 1.5 microns. Then, electron beam positive resist PMMA is further spin-coated on the surface of the AZ1500 hot-melt adhesive, with a coating thickness of 400-600 nm,
preferably 500 nm. The desired nanolens surface shape (shown in Figure 3, 24) is discretized into 2°N step-like distributions, as shown in Figure 3 (23), where N is an integer. Here, N=4 is preferred, resulting in 16 steps. The steps are then stacked and combined in 2*N to form N exposure patterns. The distribution of the exposure patterns is shown in the ring bands in Figure 2, with each ring band corresponding to a different exposure energy, as indicated by the energy ratio values in the different ring bands of
Figure 2. The N exposure patterns are then exposed sequentially based on the exposure dose ratio in the ring bands of Figure 2. During the exposure process, the entire substrate is not removed to ensure that the starting position for all N exposures remains the same.
The diameter of the largest exposure ring corresponds to the final aperture size of the nanolens to be fabricated, with a range from 200-1000 nm, and 660 nm is used as an example here. After N exposures and development, the grayscale distribution structure in the e-beam resist layer, as shown in Figure 3 (23), 1s obtained.
As another embodiment of the present invention, Step S3 employs an ICP or RIE dry etching technique, with ICP dry etching being preferred. Oxygen is used as the etching gas, with an oxygen flow rate of 40 sccm and etching power of 50-100 W, preferably 80 W. In this process, the grayscale structure on the e-beam resist PMMA, as shown in Figure 3 (23), is transferred onto the hot-melt adhesive AZ1500, as shown in
Figure 4 (32).
As one embodiment of the present invention, Step S4 uses a hot-melt process, where the grayscale structure of AZ1500, as shown in Figure 4 (32), is thermally melted on a hot plate. The melting temperature is set between 100-130" C, with 120° C being preferred, and the melting time is 1-5 minutes, preferably 2 minutes. This process causes the step-like distribution structure on the hot-melt adhesive to transform from a solid state into a nanocolloid with a certain flow state when the temperature exceeds its softening point. After the colloid flows at the nanoscale, the step-like structure on the hot-melt adhesive deforms into a structure with a continuous surface shape feature distribution and a smooth surface morphology, as shown in Figure 5 (42), thus obtaining the desired nanolens with nanoscale apertures. The aperture size of the nanolens is the same as the outer diameter of the outermost ring set during the electron beam exposure process. The continuous surface shape distribution resulting from the hot-melt deformation is directly related to the step structure distribution on the hot-melt adhesive.
The larger the lateral size interval between adjacent height step structures or the smaller the height difference between adjacent steps, the larger the curvature radius of the surface shape after melting. By controlling the inner and outer radii of the exposure rings and the exposure doses in the N exposures during Step S2, the step distribution of the e-beam resist can be controlled, which in turn controls the step distribution on the hot-melt adhesive and ultimately the surface shape distribution of the nanolens formed on the hot- melt adhesive. The method in this embodiment of the invention solves the difficulty of precise control of the surface shape of nanolenses during processing.
Embodiment 2
This embodiment of the invention also provides a method for fabricating a nanolens array, which includes:
Using a spin-coating process to sequentially spin-coat UV photoresist hot-melt adhesive and positive electron beam photoresist onto a glass substrate.
Using the gradient grayscale distribution shown in Figure 2, where the numbers inside the rings in Figure 2 represent the unit doses of electron beam exposure within the respective nanorings. For example, “0” indicates that the electron beam exposure dose within the central circle is 0 units. After development, the stepped structure shown in
Figure 3 (23) 1s formed, which rises step by step from low to high. The height of the steps is related to the unit dose of exposure in Figure 2: the larger the exposure dose units, the lower the corresponding step height in Figure 3.
Using a reactive ion etcher with oxygen plasma to transfer the step structure from the electron beam photoresist to the UV photoresist hot-melt adhesive, as shown in
Figure 4 (32). The distribution of the step heights is consistent with the distribution of the electron beam resist layer in Figure 3.
Using a hot-melt process to heat-melt the step structure of the UV photoresist into a continuous smooth nanolens structure, as shown in Figure 5 (42), on a hot plate at 120°C.
As one embodiment of the present invention, during the electron beam grayscale exposure process, the nanoscale grayscale subunits are arranged in a quadrilateral layout, as shown in Figure 6. The final nanolens array obtained after the hot-melt process is consistent with the grayscale subunit distribution during the electron beam exposure process, as shown in Figure 7. The side length of the nanolens sub-aperture is 333 nm, and the sub-aperture unit surface shape is a smooth spherical cap.
Embodiment 3
This embodiment of the invention provides a method for fabricating a nanolens array, which includes:
Using a spin-coating process to sequentially spin-coat UV photoresist hot-melt adhesive and positive electron beam photoresist onto a silicon wafer.
Using a gradient grayscale distribution to perform grayscale exposure on the electron beam resist with an electron beam lithography system. The structure formed after development.
Using an inductively coupled plasma (ICP) etcher with oxygen plasma to transfer the stepped structure from the electron beam resist to the UV photoresist hot-melt adhesive.
Using a hot-melt process to heat-melt the stepped structure of the UV photoresist into a continuous smooth nanolens structure on a hot plate at 130°C.
As one embodiment of the present invention, during the electron beam grayscale exposure process, the nanoscale grayscale subunits are arranged in a hexagonal layout, as shown in Figure 8 The final nanolens array obtained after the hot-melt process, as shown in Figure 9, has a distribution consistent with the grayscale subunit distribution during the electron beam exposure process. The nanolens sub-aperture diameter is 714 nm, and the sub-aperture unit surface shape is aspheric. The surface shape distribution is controlled by the gradient grayscale distribution during the electron beam grayscale exposure process.
The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims (8)

ConclusiesConclusions 1. Werkwijze voor het vervaardigen van een nanolens-array, gekenmerkt door de volgende stappen: S1: sequentieel spincoaten van thermoplastische lijm en elektronenbundelfotoresist op een substraat, waarbij het substraat een siliciumwafer, glasplaat of optische lens is; S2: verwerken van de elektronenbundelfotoresist tot nanoschaal sub-apertuur grijswaardenstructuren; S3: overbrengen van de grijswaardenstructuren van de elektronenbundelfotoresist op de thermoplastische lijm; S4: smelten van de grijswaardenstructuren op de thermoplastische lijm tot een nanolens- array met continue oppervlaktekenmerken.1. A method for manufacturing a nanolens array, characterized by the following steps: S1: sequentially spin coating thermoplastic adhesive and electron beam photoresist onto a substrate, the substrate being a silicon wafer, glass plate or optical lens; S2: processing the electron beam photoresist into nanoscale sub-aperture grayscale structures; S3: transferring the grayscale structures of the electron beam photoresist onto the thermoplastic adhesive; S4: melting the grayscale structures onto the thermoplastic adhesive into a nanolens array having continuous surface features. 2. Werkwijze voor het vervaardigen van een nanolens-array zoals beschreven in conclusie 1, gekenmerkt doordat stap S2 gebruikmaakt van elektronenbundelgrijswaardenbelichtingstechnologie om de elektronenbundelfotoresist te verwerken tot nanoschaal sub-apertuur grijswaardenstructuren.2. A method for manufacturing a nanolens array as set forth in claim 1, characterized in that step S2 uses electron beam grayscale exposure technology to process the electron beam photoresist into nanoscale sub-aperture grayscale structures. 3. Werkwijze voor het vervaardigen van een nanolens-array zoals beschreven in conclusie 2, gekenmerkt doordat stap S3 gebruikmaakt van droge etstechnologie om de grijswaardenstructuren van de elektronenbundelfotoresist over te brengen op de thermoplastische lijm.3. A method for manufacturing a nanolens array as described in claim 2, characterized in that step S3 uses dry etching technology to transfer the grayscale structures of the electron beam photoresist to the thermoplastic adhesive. 4. Werkwijze voor het vervaardigen van een nanolens-array zoals beschreven in conclusie 3, gekenmerkt doordat stap S4 gebruikmaakt van een thermisch smeltproces om de grijswaardenstructuren op de thermoplastische lijm te smelten tot een nanolens- array met continue oppervlaktekenmerken.4. A method for manufacturing a nanolens array as described in claim 3, characterized in that step S4 uses a thermal melting process to melt the grayscale structures on the thermoplastic adhesive into a nanolens array having continuous surface features. 5. Werkwijze voor het vervaardigen van een nanolensarray zoals beschreven in conclusie 4, gekenmerkt doordat het oppervlakteprofiel van de nanolensarray een glad optisch oppervlak is met een continue driedimensionale verdeling binnen een enkele nanoschaal sub-apertuur.5. A method of manufacturing a nanolens array as described in claim 4, characterized in that the surface profile of the nanolens array is a smooth optical surface with a continuous three-dimensional distribution within a single nanoscale sub-aperture. 6. Werkwijze voor het vervaardigen van een nanolensarray zoals beschreven in conclusie 5, gekenmerkt doordat de continue driedimensionale oppervlakteprofielverdeling van de nanoschaal sub-apertuur-eenheden in de nanolensarray wordt geregeld door de verdeling van de elektronenbundel grijswaardenbelichting.6. A method for manufacturing a nanolens array as described in claim 5, characterized in that the continuous three-dimensional surface profile distribution of the nanoscale sub-aperture units in the nanolens array is controlled by the distribution of the electron beam grayscale illumination. 7. Werkwijze voor het vervaardigen van een nanolensarray zoals beschreven in conclusie 6, gekenmerkt doordat het substraat een siliciumwafer, glasplaat of optische lens is.7. A method for manufacturing a nanolens array as described in claim 6, characterized in that the substrate is a silicon wafer, glass plate or optical lens. 8. Werkwijze voor het vervaardigen van een nanolensarray zoals beschreven in conclusie 7, gekenmerkt doordat het droge etsen zuurstofplasma-etsen is.8. A method for manufacturing a nanolens array as described in claim 7, characterized in that the dry etching is oxygen plasma etching.
NL2039587A 2024-02-01 2025-01-13 A method for fabricating a nanolens array NL2039587A (en)

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Application Number Priority Date Filing Date Title
CN202410142295.XA CN118112698A (en) 2024-02-01 2024-02-01 Method for manufacturing nano lens array

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NL2039587A true NL2039587A (en) 2025-02-17

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