A nanobelt array film and a method for preparing the same

Abstract

The application discloses a nanobelt array film and a preparation method thereof, relates to nanometer film technology, and aims at the uncontrollable nanometer domain sample in the prior art. The nanobelt array film is prepared by providing physical confinement to diblock copolymer by using nanometer grooves arranged in a periodic array, making the diblock copolymer generate first block molecules and second block molecules arranged at intervals in a directional manner, etching one of the block molecules of the diblock copolymer by using the difference between the etching properties of the first block molecules and the second block molecules, and etching a film layer by using the residual block molecules as a mask. The nanobelt array film has the advantages that the preparation of sub-10-nanometer lines with large area, high uniformity, controllable position and orientation is realized, and the residual block molecules are used as a mask to efficiently and accurately complete deep patterning of an underlying film. The nanobelt array film can provide a solution with high resolution, low cost and good process expandability for nanoelectronic, optoelectronic devices and advanced integrated circuit manufacturing.

Description

Technical Field

[0001] This invention relates to nanofilm technology, and more particularly to a nanobelt array thin film and its preparation method. Background Technology

[0002] As the feature size of semiconductor devices continues to shrink, nanoscale patterning processes face extremely high demands in terms of resolution, uniformity, and cost control. Currently, mainstream technologies in this field still have significant limitations: advanced lithography equipment such as extreme ultraviolet (EUV) lithography is complex and expensive; while technologies such as deep ultraviolet lithography still face significant technical difficulties in achieving sub-20 nanometer resolution. Electron beam and ion beam lithography offer extremely high resolution as research tools, but their serial writing mode results in extremely low throughput and high cost, making them unsuitable for large-scale production.

[0003] Block copolymer self-assembly is a promising mask patterning method that can form periodic structures of 5–50 nm through microphase separation. However, the orientation and position of the self-assembled domains are random, lacking long-range order. Although "chemical epitaxy" or "pattern epitaxy" can be used for guidance, the process is complex, and the resulting polymer domains are relatively thin (typically <50 nm), limiting their etching resistance and pattern transfer capabilities as etching masks, making it difficult to achieve high aspect ratio structures.

[0004] In summary, existing technologies fail to achieve a good balance between controllability, resolution, process simplicity, and pattern transfer capability. Therefore, there is an urgent need for a novel hybrid nanofabrication strategy that can precisely guide the formation of ultrafine nanomasks and achieve efficient pattern transfer. Summary of the Invention

[0005] The purpose of this invention is to provide a nanobelt array thin film and its preparation method to solve the problems existing in the prior art.

[0006] The method for preparing a nanoribbon array thin film described in this invention utilizes periodically arrayed nanogrooves to provide physical confinement for a diblock copolymer, causing the diblock copolymer to directionally generate spaced first and second block molecules. Taking advantage of the difference in etching properties between the first and second block molecules, one block molecule of the diblock copolymer is etched. Using the other block molecule of the diblock copolymer as a mask, the thin film layer is etched to obtain the nanoribbon array thin film.

[0007] The nanoribbon array thin film described in this invention is prepared using the method described above.

[0008] The nanoribbon array thin film and its fabrication method described in this invention have the advantages of enabling the fabrication of large-area, highly uniform, and positionally and orientably controllable sub-10 nanometer lines. These lines can then be used as masks to efficiently and precisely perform deep patterning of the underlying thin film. This provides a solution for the manufacturing of nanoelectronics, optoelectronic devices, and advanced integrated circuits that combines high resolution, low cost, and good process scalability. Attached Figure Description

[0009] Figure 1 This is a flowchart illustrating the preparation method described in this invention. Figure 1 .

[0010] Figure 2 This is a flowchart illustrating the preparation method described in this invention. Figure 2 .

[0011] Figure 3 yes Figure 2 A magnified view of a portion of point A in the middle.

[0012] Figure 4 This is a flowchart illustrating the preparation method described in this invention. Figure 3 .

[0013] Figure 5 This is a flowchart illustrating the preparation method described in this invention. Figure 4 .

[0014] Figure 6 This is a flowchart illustrating the preparation method described in this invention. Figure 5 .

[0015] Figure 7 This is a flowchart illustrating the preparation method described in this invention. Figure 6 .

[0016] Figure 8 This is a schematic diagram of the structure of a nanoribbon array thin film described in this invention.

[0017] Figure label: 100-substrate; 200 - thin film layer, 201 - nanometer array; 300 - hard mask, 301 - nanogroove; 400 - Photoresist mask; 401 - Pattern; 501 - First block molecule, 502 - Second block molecule; W - width of the nanogroove, D - depth of the nanogroove. Detailed Implementation

[0018] Binary block copolymer films consist of periodic nanostructures formed by alternating horizontal arrangements of two types of blocks. However, on flat substrates without regular patterns, the nanowires formed are typically curved, making them difficult to use directly as highly regular nanowire masks required in integrated circuit manufacturing. To address this issue, this invention proposes a method for preparing nanoribbon array films, specifically including the following steps: A stacked sample with a substrate 100 / thin film layer 200 / hard mask 300 sandwich structure is prepared. The substrate 100 can be silicon, glass, or a flexible substrate, etc. The thin film layer 200 can be a semiconductor, oxide dielectric, metal, or two-dimensional material, etc. The hard mask 300 can be SiO2. x SiN x wait.

[0019] Photoresist is coated onto the surface of a hard mask 300 / thin film layer 200 stack using deep ultraviolet lithography, electron beam lithography, or nanoimprint lithography. After exposure and development, a photoresist mask 400 with a linear array pattern 401 is formed. Figure 1 As shown. The photoresist pattern is transferred to the underlying hard mask 300 via reactive ion etching or wet etching, forming a series of parallel-extending nanogrooves 301. The width W of the nanogrooves 301 is designed to be 100 nm to 500 nm, and the depth D is 20 nm to 200 nm. Subsequently, any remaining photoresist is thoroughly removed, as shown... Figure 2 , Figure 3 As shown. Compared to existing technologies where polymer nanodomains are generally below 50 nm and their thinness makes them unsuitable for subsequent masking, the thickness of the nanodomains prepared in this invention is controlled by the depth D, offering a wide controllable range. This allows for the preparation of both thin and thick masks, making it more adaptable to subsequent processes.

[0020] A solution is prepared by dissolving the diblock copolymer in a suitable solvent using a spin coater or drop coater. The diblock copolymer can be polystyrene-polydimethylsiloxane PS-b-PDMS, polystyrene-polymethyl methacrylate PS-b-PMMA, polybutyl acrylate-polyethylene oxide PBA-b-PEO, or polytrimethylsilyl styrene-polylactic acid PTMSS-b-PLA, where b represents a block structure. The solvent can be toluene, chlorobenzene, etc. The solution is coated onto the sample surface with nanogrooves 301, and centrifugal force or capillary action is used to fill the nanogrooves 301. Subsequently, thermal annealing or solvent annealing is performed, causing the diblock copolymer to undergo directional assembly under the physical confinement of the nanogrooves 301, whereby one block molecule forms periodically arranged nanodomains within the matrix of the other block molecule. Without loss of generality, in this embodiment, the second block molecule 502 is described as forming the nanodomains within the matrix of the first block molecule 501, such as... Figure 4As shown. The first block molecule 501 can be selected from polystyrene PS, polybutyl acrylate PBA, or polytrimethylsilyl styrene PTMSS, etc.; the second block molecule 502 can be selected from polydimethylsiloxane PDMS, polymethyl methacrylate PMMA, polyethylene oxide PEO, or polylactic acid PLA, etc.

[0021] If thermal annealing is used, the annealing temperature is 80°C to 250°C, and the time is 10 minutes to 24 hours. If solvent annealing is used, it is carried out in a solvent vapor atmosphere. The type of solvent is selected according to the block copolymer material, and the annealing temperature can be 25°C to 80°C, and the annealing time can be 10 minutes to 24 hours. During the annealing process, the nanodomains are uniformly arranged with a width and spacing of sub-10 nanometers and in a long-range ordered manner along the 301 direction of the nanogrooves. Under the technical guidance of this invention, those skilled in the art, combined with common knowledge, can achieve adjustable nanodomain width and spacing from 5 nanometers to 30 nanometers by controlling the molecular weight of each block during the synthesis process through a limited number of experiments.

[0022] Oxygen plasma etching is performed using an oxygen plasma etching machine under specific process conditions, such as a power of 50-300W, a gas pressure of 10-100 mTorr, and a time of 10-300 seconds. Due to the different chemical compositions of the two blocks, their resistance to oxygen plasma etching varies significantly. For example, PS is easily oxidized and volatilized, while PDMS or PMMA oxidizes to form a more resistant layer. In this embodiment, after etching, the resistant first block molecule 501 is completely removed, while the resistant second block molecule 502 is retained. This results in a sub-10 nanometer width array of nanolines composed of a single resistant molecular material within each nanogroove 301. This array serves as an ultra-narrow molecular mask for subsequent etching. Figure 5 As shown.

[0023] The lower thin film region not covered by the ultranarrow molecular mask is removed using reactive ion etching equipment or wet etching tank, thereby transferring the sub-10 nanometer line pattern to the target thin film with high fidelity, forming a nanoarray 201, such as... Figure 6As shown. If dry etching is used, a gas chemical system with an extremely low etching rate for the molecular mask material but a high etching rate for the underlying target film should be selected. For example, SF6 / CF4 plasma can be used for silicon thin films and two-dimensional material thin films; CHF3 / BCl3 plasma can be used for oxide media (such as SiO2, Al2O3, IGZO, and other metal oxides); and Cl2 / BC3 zero plasma can be used for metals. During etching, the RF power is controlled at 50-500 W, the chamber pressure is maintained at 5-100 mTorr, and the etching time is adjusted according to the required patterning depth, typically from 10 seconds to 5 minutes. If wet etching is used, a chemical solution that can specifically dissolve the target film without damaging the molecular mask should be selected. For example: using a potassium hydroxide solution with a mass fraction of 10%-30% to etch single-crystal silicon or polycrystalline silicon thin films; using dilute hydrochloric acid or phosphoric acid-based solutions to etch metal oxide semiconductor layers such as IGZO; using appropriate metal etching solutions (such as potassium iodide-iodine solution for gold, and a mixture of phosphoric acid-nitric acid-acetic acid for aluminum) to etch metal thin layers; using hydrogen peroxide-based solutions or oxidizing acid mixtures to etch two-dimensional transition metal sulfide materials such as MoS2.

[0024] The ultra-narrow molecular mask is removed using oxygen plasma ashing or wet cleaning. If using strong oxygen plasma ashing: plasma treatment is performed for 1-10 minutes at 100-500 W in an oxygen atmosphere to completely oxidize and volatilize the residual organic mask material. If using wet cleaning: an appropriate solvent is selected based on the properties of the mask material. For example, dilute hydrofluoric acid solution is used to remove oxidized organic mask residue, or organic solvents such as acetone or N-methylpyrrolidone are used to clean polymer residue. After cleaning, rinsing with deionized water and drying with nitrogen gas yields a clean, structurally intact nanopatterned thin film, such as... Figure 7 As shown. The final result is as follows. Figure 8 The nanoribbon array thin film shown.

[0025] The nanoribbon array thin film described in this invention is prepared using the method described above, and its structure is as follows: Figure 8 As shown.

[0026] This invention has the following advantages: Ultra-high resolution and precise control: Utilizing the physical confinement effect of nanogrooves 301, the self-assembly of diblock copolymers is precisely guided, enabling the fabrication of large-area, long-range ordered nanoline nanowires with sub-10 nm widths, with controllable position and orientation. This breaks through the resolution limits and randomness limitations of traditional photolithography. Specifically, a single process can cover 4-inch wafers and can be expanded to 6-8 inches, with ordered domain sizes exceeding 10 micrometers.

[0027] Lower process costs: The core patterning steps rely on self-assembly and conventional plasma etching, avoiding the use of expensive, high-end lithography equipment throughout the process, which significantly reduces manufacturing costs.

[0028] Superior mask performance: Molecular line masks obtained through selective etching typically have excellent etching selectivity, allowing thinner masks to be directly used for high-fidelity pattern transfer in subsequent processes.

[0029] High compatibility and flexibility: Applicable to a variety of substrates (silicon, glass, flexible substrates, etc.) and thin film materials (semiconductors, oxide media, metals, two-dimensional materials). By adjusting the design of the nanogroove 301, the co-embedded molecular structure and the etching process, nanostructures of different sizes, shapes and materials can be flexibly prepared, with broad application prospects.

[0030] For those skilled in the art, various other corresponding changes and modifications can be made based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of this invention.

Claims

1. A method for preparing a nanoribbon array thin film, characterized in that, The diblock copolymer is physically confined by periodically arrayed nanogrooves (301), causing the diblock copolymer to directionally generate spaced first block molecules (501) and second block molecules (502). The difference in etching properties between the first block molecules (501) and the second block molecules (502) is used to etch one block molecule of the diblock copolymer. The other block molecule of the diblock copolymer is used as a mask to etch the thin film layer (200) to obtain the nanobelt array thin film.

2. The method for preparing a nanoribbon array thin film according to claim 1, characterized in that, The preparation steps of the nanogroove (301) are as follows: A photoresist mask (400) with a pattern (401) is disposed on a hard mask (300); the pattern (401) is periodically arrayed on the photoresist mask (400); The photoresist mask (400) is developed and etched to transfer the pattern (401) to the hard mask (300); nanogrooves (301) are periodically arrayed in the hard mask (300).

3. The method for preparing a nanoribbon array thin film according to claim 2, characterized in that, The width W of the nanogroove (301) is 100nm to 500nm; the depth D of the nanogroove (301) is 20nm to 200nm.

4. The method for preparing a nanoribbon array thin film according to claim 3, characterized in that, The steps for generating the first block molecule (501) and the second block molecule (502) are as follows: A diblock copolymer solution is prepared; the diblock copolymer solution is filled into the nanogroove (301) and annealed; one block molecule of the diblock copolymer forms a periodically arranged nanodomain in the matrix of the other block molecule, and the nanodomain is directionally generated under the physical confinement of the nanogroove (301).

5. The method for preparing a nanoribbon array thin film according to claim 4, characterized in that, The width and spacing of the nanodomains are in the sub-10 nanometer range.

6. The method for preparing a nanoribbon array thin film according to claim 5, characterized in that, By utilizing the difference in oxygen plasma etching resistance, the non-etchable block molecules in the diblock copolymer are etched away, while the other etchable block molecule is retained in the nanogroove (301).

7. The method for preparing a nanoribbon array thin film according to claim 6, characterized in that, After obtaining the nanobelt array film, the block molecules used as the mask are removed by oxygen plasma ashing or wet cleaning.

8. The method for preparing a nanoribbon array thin film according to claim 7, characterized in that, Polystyrene-dimethylsiloxane, or polystyrene-polymethyl methacrylate, or polybutyl acrylate-polyethylene oxide, or polytrimethylsilylstyrene-polylactic acid.

9. The method for preparing a nanoribbon array thin film according to claim 8, characterized in that, The annealing process is either thermal annealing or solvent annealing; The annealing temperature for hot annealing is 80°C to 250°C, and the time is 10 minutes to 24 hours. Solvent annealing is carried out in a solvent vapor atmosphere at a temperature of 25°C to 80°C for 10 minutes to 24 hours.

10. A nanoribbon array thin film, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.

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