Method for preparing high-resolution pattern based on gas cluster etching

Abstract

The invention provides a method for preparing a high-resolution pattern based on gas cluster etching, and relates to the technical field of photoetching, and the method comprises the following steps: preparing a block copolymer film layer with a vertical structure epitaxial pattern on the surface of a substrate by adopting a block copolymer; preparing a gas cluster ion beam by using the etching gas; and bombarding the segmented copolymer film layer with the epitaxial pattern of the vertical structure by using a gas cluster ion beam, and selectively etching the segmented copolymer film layer to form a high-resolution pattern. By reasonably regulating and controlling gas cluster etching parameters, a high-resolution pattern with a flat and smooth surface, small line edge roughness and excellent contrast can be prepared.

Description

Technical Field

[0001] The present disclosure relates to the field of lithography technology, and particularly to a method for preparing high-resolution patterns based on gas cluster etching. Background Art

[0002] Based on the Directed Self-Assembly (DSA) technology of Block Copolymers (BCPs), without the need for a light source and a mask, high-resolution patterns can be obtained through molecular self-assembly, which can break through the diffraction limit of traditional lithography. BCPs are polymerized from two monomers with different chemical properties. Due to the thermodynamic incompatibility between different polymer segments, microphase separation occurs. After annealing, nano-scale patterns can be obtained, and finally, the patterns can be induced into periodic nano gratings or nanohole arrays through controllable adjustment. This DSA technology can achieve sub-10 nm lithography process and is expected to be widely applied in the next-generation lithography technology.

[0003] Although high-resolution patterns can be obtained after the induction of BCPs, selective etching is still required to form an etching template, and then the template pattern is transferred to the substrate through subsequent etching technology to prepare ultra-high-resolution nanostructures and related micro-nano devices. Common etching technologies such as Reactive Ion Etching (RIE), Inductively Coupled Plasma (ICP) etching, and Ion Beam Etching (IBE) have poor etching selectivity between organic substances and organic substances, and the Low Frequency Line Width Roughness (LWR) and Line Edge Roughness (LER) of the patterns after etching are large, and even contrast patterns cannot be etched. In the process of DSA etching transfer, Sequential Infiltration Synthesis (SIS) can be used as an etching transfer option, which requires one of the polymer segments in BCPs to be selectively Atomic Layer Deposition (ALD) and generate the corresponding metal oxide. Subsequently, a Reactive Ion Beam Etching (RIE) system is used to selectively etch the organic-inorganic combination generated in BCPs to obtain the required pattern. However, the introduction of inorganic metal elements will cause difficulties in subsequent removal and device contamination problems. Therefore, in order to ensure the quality of pattern transfer and the requirements of subsequent device processing, it is extremely important to develop an etching scheme with high selectivity between different block polymers of BCPs and without introducing pollutants. Summary of the Invention

[0004] In view of this, embodiments of the present disclosure provide a method for preparing a high-resolution pattern based on gas cluster etching.

[0005] Embodiments of the present disclosure provide a method for preparing a high-resolution pattern based on gas cluster etching, including: preparing a block copolymer film layer with a vertically structured epitaxial pattern on a substrate surface using a block copolymer; preparing a gas cluster ion beam using an etching gas; bombarding the block copolymer film layer with the vertically structured epitaxial pattern with the gas cluster ion beam to selectively etch the block copolymer film layer to form a high-resolution pattern.

[0006] According to an embodiment of the present disclosure, preparing a gas cluster ion beam using an etching gas includes: condensing and ultrasonically expanding a high-pressure gas containing at least one etching gas to form clusters having a size within an initial size range; accelerating particles of the clusters having a size within the initial size range through ionization, and filtering out clusters having a size smaller than a size threshold using a magnetic separator to obtain clusters having a size within a target size range.

[0007] According to an embodiment of the present disclosure, the etching gas includes Ar, O 2 , F 2 , Cl 2 , Br 2 and at least one of the corresponding halides and haloalkanes of Ar, O 2 , F 2 , Cl 2 , Br 2 ; the initial size range is 50 atoms / ion to 5000 atoms / ion, the size threshold is 1000 atoms / ion, and the initial size range is 1000 atoms / ion to 5000 atoms / ion.

[0008] According to an embodiment of the present disclosure, bombarding the block copolymer film layer with the vertically structured epitaxial pattern perpendicularly with the gas cluster ion beam, wherein the pressure of the high-pressure gas is 1 MPa to 100 MPa, the acceleration voltage is 500 V to 30 kV, and the ionization energy of a single atom is 0.5 eV to 10 eV.

[0009] According to an embodiment of the present disclosure, the vertically structured epitaxial pattern of the block copolymer film layer includes a physical epitaxial pattern. Preparing a block copolymer film layer with a vertically structured epitaxial pattern on a substrate surface using a block copolymer includes: coating the block copolymer on a substrate with undulations composed of a photoresist or an etched pattern, and annealing to form a physical epitaxial pattern.

[0010] According to an embodiment of the present disclosure, the vertical structure epitaxial pattern of the block copolymer film layer includes a chemical epitaxial pattern. The method for preparing a block copolymer film layer with a vertical structure epitaxial pattern on a substrate surface using a block copolymer includes: coating the block copolymer on a flat patterned substrate composed of alternating chemical components, and annealing to form a chemical epitaxial pattern.

[0011] According to an embodiment of the present disclosure, the vertical structure epitaxial pattern of the block copolymer film layer includes a self-assembled pattern without orientation. The method for preparing a block copolymer film layer with a vertical structure epitaxial pattern on a substrate surface using a block copolymer includes: coating the block copolymer on a flat patterned substrate composed of a single chemical component, and annealing to form a self-assembled pattern without orientation.

[0012] According to an embodiment of the present disclosure, the annealing temperature corresponding to the block copolymer film layer is 50 °C to 250 °C, the annealing time is 0.5 h to 48 h, and the annealing of the block copolymer film layer is carried out in a nitrogen atmosphere or an organic solvent vapor atmosphere. The organic solvent includes at least one of acetone, tetrahydrofuran, and N,N-dimethylformamide; the thickness of the block copolymer film layer is 10 nm to 50 nm.

[0013] According to an embodiment of the present disclosure, the block copolymer includes one of polystyrene-b-polymethyl methacrylate, polystyrene-b-polyisoprene, polystyrene-b-polylactic acid, polystyrene-b-poly(dimethylsiloxane), polystyrene-b-poly(trimethylene carbonate), polystyrene-b-poly(2-vinylpyridine), polystyrene-b-poly(propylene carbonate), poly(4-tert-butylstyrene)-b-polymethyl methacrylate, polystyrene-b-poly(acetone glycerol acrylate), polystyrene-b-poly(lactic-co-glycolic acid), polystyrene-b-poly(methyl acrylate), polystyrene-b-poly(acetone glycerol methacrylate), polystyrene-b-poly(4-hydroxystyrene), polystyrene-b-poly(4-vinylpyridine), polystyrene-b-poly(2,2,2-trifluoroethyl acrylate), poly(4-tert-butylstyrene)-b-poly(2-vinylpyridine), poly(vinylcyclohexane)-b-polymethyl methacrylate, poly(dimethylsiloxane)-b-polymethyl methacrylate, polystyrene-b-poly(pentafluorooctyl methacrylate), polystyrene-b-poly(hydroxyisobutene), polystyrene-b-poly(acrylic acid), polystyrene-b-poly(3,4-dihydroxystyrene), poly(4-(trimethylsilyl)styrene)-b-polylactic acid, polystyrene-b-poly(2,3-dihydroxypropyl methacrylate), poly(2-vinylpyridine)-b-poly(heptafluorobutyl-2-methylprop-2-enoate), poly(3-hydroxystyrene)-b-poly(dimethylsiloxane).

[0014] The method for preparing high-resolution patterns based on gas cluster etching provided by an embodiment of the present disclosure has at least the following technical effects:

[0015] This method directly uses gas clusters to act on the BCPs layer for selective etching. The operation is simple, without the need to use ALD deposition to enhance the etching selectivity between polymer segments, simplifies the preparation process, and avoids the introduction of contaminating elements.

[0016] The selectivity of gas clusters for block copolymers is based on the chemical bonds inside their structures. By reasonably designing the copolymer segment composition and chemical structure, a high etching selectivity can be achieved between organic segments. The quality of the patterns obtained after etching is high, and the LWR and LER are small.

[0017] Each particle in the gas cluster has a similar velocity and low average energy, and will not damage the deep-layer atoms of the material being etched during the etching process.

[0018] By regulating parameters such as gas cluster size, gas source pressure, acceleration voltage, ionization energy, etc., precise control of etching parameters such as etching depth, rate, roughness, etc. can be achieved, and high-resolution patterns with a flat and smooth surface, small line-edge roughness, and excellent contrast can be prepared. This method can also be combined with processes such as continuous infiltration deposition, wet etching, and stripping for pattern transfer. Description of the Drawings

[0019] Through the following description of the embodiments of the present disclosure with reference to the drawings, the above and other objects, features, and advantages of the present disclosure will become clearer. In the drawings:

[0020] Figure 1 Schematically shows a flowchart of the method for preparing high-resolution patterns based on gas cluster etching according to an embodiment of the present disclosure.

[0021] Figure 2 Schematically shows an implementation process diagram of the method for preparing high-resolution patterns based on gas cluster etching.

[0022] Figure 3 Schematically shows a morphology diagram of the self-assembled pattern of the block copolymer after etching according to Embodiment 1 of the present disclosure.

[0023] Figure 4 Schematically shows a morphology diagram of the self-assembled pattern of the block copolymer after etching according to Embodiment 2 of the present disclosure.

[0024] Figure 5 Schematically shows a morphology diagram of the self-assembled pattern of the block copolymer after etching according to Comparative Example 1 of the present disclosure. Detailed Embodiments

[0025] To make the objectives, technical solutions, and advantages of the present disclosure more clearly understood, the following further elaborates on the present disclosure in detail with reference to specific embodiments and the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without creative efforts fall within the scope of protection of the present disclosure.

[0026] The terms used herein are merely for describing specific embodiments and are not intended to limit the present disclosure. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Therefore, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present disclosure, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0027] Since BCPs are composed of an organic-organic structure and the polymer blocks are mostly distinguished by chemical bonds or functional groups, it is difficult for RIE and ICP to form highly selective etching for the organic blocks in BCPs, resulting in greater damage to the surface, causing contamination, and making it difficult to obtain high-resolution patterns. IBE is a physical etching method with a slow etching rate, lower efficiency than RIE and ICP, and almost no selectivity between different organic materials, so it is also not suitable for etching between polymer blocks. Regarding the problem of difficult selective etching of different polymers, although the SIS technology can ensure a high etching selectivity ratio between different polymer blocks, the introduced metal elements are difficult to remove and will contaminate the subsequent device processing. In view of this, the embodiments of the present disclosure provide a method for preparing high-resolution patterns based on gas cluster etching.

[0028] Figure 1 A flowchart of a method for preparing high-resolution patterns based on gas cluster etching according to an embodiment of the present disclosure is schematically shown. Figure 2 An implementation process diagram of a method for preparing high-resolution patterns based on gas cluster etching is schematically shown.

[0029] As Figure 1 and Figure 2 shown, the method for preparing high-resolution patterns based on gas cluster etching provided in this embodiment may include operation S110 to operation S130.

[0030] In operation S110, a block copolymer film layer with a vertically structured epitaxial pattern is prepared on the substrate surface using a block copolymer.

[0031] In operation S120, a gas cluster ion beam is prepared using an etching gas.

[0032] In operation S130, the block copolymer film layer with a vertical structure epitaxial pattern is bombarded with the gas cluster ion beam to perform selective etching on the block copolymer film layer, thereby forming a high-resolution pattern.

[0033] According to an embodiment of the present disclosure, gas cluster ion beam (GCIB) etching has a series of characteristics that are not possessed by a series of conventional plasma etching. A gas cluster is a relatively stable aggregate formed by several to tens of thousands of atoms or molecules under physical or chemical action. In a GBIC etching device, a very high energy can be obtained through an acceleration electrode for GCIB, a high energy density can be formed in a local area, and various physical and chemical reactions can be excited near the surface of the etched material. Each particle in the gas cluster has a similar velocity and a low average energy, and will not damage the deep-layer atoms of the acting material during the etching process. In addition, the organic structure is relatively loose and the bond energy is low. GCIB can break the chemical bonds of organic substances at a relatively low kinetic energy. Since different chemical bonds can withstand different energies of cluster ions, when the chemical structures of different blocks of the copolymer are reasonably designed to have an obvious distribution contrast in chemical bonds, by adjusting the etching process parameters (such as cluster size, energy) to ensure that the low energy density of the cluster ions can break the weak bonds in the organic substances without damaging the bonds with stronger bond energies, selective etching of BCPs by GCIB can be achieved. Therefore, using GCIB to selectively etch organic substances with different structures in BCPs is the most effective method to achieve high-resolution pattern transfer of DSA.

[0034] In some embodiments, before preparing the block copolymer film layer on the substrate surface, the substrate surface can be cleaned. The substrate can be ultrasonically cleaned in acetone, ethanol, and deionized water in sequence for 30 min to 60 min. After the cleaning is completed, the substrate is removed and the liquid on the substrate surface is blown dry with nitrogen, and then placed in an oven for drying to remove the residual liquid on the substrate surface.

[0035] According to an embodiment of the present disclosure, according to the difference in the guiding manner of the block copolymer, the vertical structure epitaxial pattern of the block copolymer film layer can include one of a physical epitaxial pattern, a chemical epitaxial pattern, and a non-directed self-assembly pattern.

[0036] Based on the physical epitaxial pattern, the phase domains in the block copolymer thin film layer can self-assemble into a long-range ordered structure according to the pattern designed by the physical epitaxial pattern. Based on the chemical epitaxial pattern, the phase domains in the block copolymer thin film layer can self-assemble into a long-range ordered structure according to the pattern designed by the chemical epitaxial pattern. Based on the non-directed self-assembly pattern, a non-directed fingerprint-like pattern can be formed in the block copolymer thin film layer.

[0037] In some embodiments, to prepare a block copolymer film layer with a vertically structured epitaxial pattern on a substrate surface using a block copolymer may include: coating the block copolymer on a substrate with undulations composed of a photoresist or an etched pattern, and annealing to form a physical epitaxial pattern.

[0038] In some other embodiments, to prepare a block copolymer film layer with a vertically structured epitaxial pattern on a substrate surface using a block copolymer includes: coating the block copolymer on a flat patterned substrate composed of alternating chemical components, and annealing to form a chemical epitaxial pattern

[0039] In some other embodiments, to prepare a block copolymer film layer with a vertically structured epitaxial pattern on a substrate surface using a block copolymer may include: coating the block copolymer on a flat patterned substrate composed of a single chemical component, and annealing to form a directed self-assembly pattern. In some embodiments, the annealing temperature corresponding to the block copolymer film layer is 50 °C to 250 °C, the annealing time is 0.5 h to 48 h, the annealing of the block copolymer film layer is carried out in a nitrogen atmosphere or an organic solvent vapor atmosphere, and the organic solvent includes but is not limited to at least one of acetone, tetrahydrofuran, and N,N-dimethylformamide; the thickness of the block copolymer film layer is 10 nm to 50 nm.

[0040] In some embodiments, as shown in Table 1 and Table 2, the block copolymer may include one of polystyrene-b-polymethyl methacrylate, polystyrene-b-polyisoprene, polystyrene-b-polylactic acid, polystyrene-b-polydimethylsiloxane, polystyrene-b-polytrimethylene carbonate, polystyrene-b-poly(2-vinylpyridine), polystyrene-b-polypropylene carbonate, poly(4-tert-butylstyrene)-b-polymethyl methacrylate, polystyrene-b-poly(acetone glycerol acrylate), polystyrene-b-poly(lactic-co-glycolic acid), polystyrene-b-poly(methyl acrylate), polystyrene-b-poly(acetone glycerol methacrylate), polystyrene-b-poly(4-hydroxystyrene), polystyrene-b-poly(4-vinylpyridine), polystyrene-b-poly(2,2,2-trifluoroethyl acrylate), poly(4-tert-butylstyrene)-b-poly(2-vinylpyridine), poly(vinylcyclohexane)-b-polymethyl methacrylate, polydimethylsiloxane-b-polymethyl methacrylate, polystyrene-b-poly(pentafluorooctyl methacrylate), polystyrene-b-poly(hydroxyisobutene), polystyrene-b-poly(acrylic acid), polystyrene-b-poly(3,4-dihydroxystyrene), poly(4-trimethylsilylstyrene)-b-polylactic acid, polystyrene-b-poly(2,3-dihydroxypropyl methacrylate), poly(2-vinylpyridine)-b-poly(heptafluorobutyl-2-methylprop-2-enoate), poly(3-hydroxystyrene)-b-polydimethylsiloxane.

[0041] Table 1 Chinese and English names and abbreviations of block copolymers

[0042]

[0043] Table 2 Chinese and English names and abbreviations of block copolymers

[0044]

[0045] In some embodiments, preparing a gas cluster ion beam using an etching gas may include:

[0046] Condensing and ultrasonically expanding a high-pressure gas containing at least one etching gas to form clusters with a size within an initial size range.

[0047] Accelerating particles of the clusters with a size within the initial size range through ionization, and filtering out clusters with a size smaller than a size threshold using a magnetic separator to obtain clusters with a size within a target size range.

[0048] In some embodiments, the etching gas may include Ar, O 2 , F 2 , Cl 2 , Br 2and Ar, O 2 , F 2 , Cl 2 , Br 2 At least one of the corresponding halides and haloalkanes. High-pressure gas containing at least one etching gas can be condensed and ultrasonically expanded to form clusters of 50 atoms / ion to 5000 atoms / ion. The cluster ions are accelerated by ionization, and clusters with a size less than 1000 atoms / ion are filtered out using a magnetic mass separator. After screening, clusters with a size between 50 atoms / ion and 5000 atoms / ion are selected for subsequent selective etching. The sample to be etched is placed on the sample stage, and the cluster ion beam is adjusted to vertically bombard the BCPs film layer. The pressure of the high-pressure gas is set to 1 MPa to 100 MPa, the acceleration voltage value is 500 V to 30 kV, and the energy of a single atom is 0.5 eV to 10 eV.

[0049] In some embodiments, after the selective etching using GCIB is completed, a scanning electron microscope (SEM) and an atomic force microscope (AFM) can be used to measure the morphologies of the original BCPs film layer and the film layer after GCIB selective etching within an area range of 1 μm × 1 μm. For example, by observing the morphological changes and etching depth of the PS-b-PMMA film layer, the etching selectivity ratio of GCIB for the PS and PMMA phases can be obtained. The etching selectivity ratio is the ratio of the etching rates of the PS and PMMA phases. The higher the etching selectivity ratio, the better the etching selectivity of GCIB.

[0050] To further clearly illustrate the method for preparing high-resolution patterns based on gas cluster etching provided by the embodiments of the present disclosure, some embodiments and comparative examples are provided below for description.

[0051] Example 1:

[0052] In Example 1, the method for preparing high-resolution patterns based on gas cluster etching can be as follows:

[0053] (1) Substrate cleaning: In an ultrasonic cleaning machine, the Si substrate is sequentially placed in acetone, ethanol, and deionized water and ultrasonically cleaned for 30 min to remove contaminants on the wafer surface. After cleaning, the Si substrate is taken out and the surface liquid is blown dry with nitrogen, and finally placed in an oven for drying to completely remove the residual surface liquid;

[0054] (2) Growth of BCPs film layer: PS-b-PMMA is spin-coated on the PS-r-PMMA-OH modified Si substrate to form a 20-nm-thick block copolymer film layer. After thermal annealing, a non-directed self-assembled pattern is obtained;

[0055] (3)GCIB etching: Condense high-pressure Ar gas and expand it ultrasonically to form gas clusters with sizes ranging from 50 atoms / ion to 5000 atoms / ion. Accelerate the gas cluster ions through ionization, and use a magnetic mass separator to filter out clusters with sizes less than 1000 atoms / ion. After screening, adjust the acceleration voltage to 500 V, the high-pressure Ar gas pressure to 10 MPa, the single atomic energy to 0.5 eV, and select clusters with an average size of 1500 atoms / ion to vertically bombard the Si substrate after the self-assembly of BCPs;

[0056] (4)Morphology observation: Use AFM to measure the morphology of the BCPs film layer after GCIB etching within an area range of 1 μm × 1 μm, and observe the morphological changes and etching depth of the BCPs film layer.

[0057] Figure 3 Schematically shows the morphology diagram of the self-assembled pattern of the block copolymer after etching according to Embodiment 1 of the present disclosure.

[0058] As Figure 3 shown, a is the SEM image, b is the AFM image, c is the size measurement image. It can be seen from Figure 4 this that at this time, the height difference between the two-phase interfaces of PS and PMMA is greater than 3 nm, the surface of the etched pattern is smooth, and the contrast of the two-phase pattern is excellent. The etching selectivity ratio of GCIB for the two phases of PS and PMMA = 1:3.5.

[0059] Example 2:

[0060] In Example 2, the method for preparing high-resolution patterns based on gas cluster etching can be as follows:

[0061] (1)Substrate cleaning: In an ultrasonic cleaning machine, place the FTO substrate in acetone, ethanol, and deionized water in sequence and ultrasonically clean for 45 min to remove contaminants on the substrate surface. After cleaning, take out the FTO substrate and blow dry the surface liquid with nitrogen, and finally put it into an oven for drying to completely remove the residual surface liquid;

[0062] (2)Growth of BCPs film layer: Spin-coat a 10-nm-thick crosslinkable PS-r-PMMA neutral layer on the FTO substrate and fully cure it. Subsequently, spin-coat the PS-b-PLA solution on the neutral layer to form a block copolymer film layer with a thickness of about 15 nm. After thermal annealing, an unoriented self-assembled pattern is obtained;

[0063] (3)GCIB etching: Condense high-pressure O 2The gas condenses and expands ultrasonically to form gas clusters with sizes ranging from 50 atoms / ion to 5000 atoms / ion. The gas cluster ions are accelerated through ionization, and clusters with sizes less than 1000 atoms / ion are filtered out using a magnetic mass separator. After screening, the acceleration voltage is adjusted to 30 kV, and the high-pressure O 2 The pressure of the gas is 30 MPa, the single-atom energy is 10 eV, and clusters with an average size of 3000 atoms / ion are selected to vertically bombard the FTO substrate after the self-assembly of BCPs;

[0064] (4)Morphology observation: The morphology of the BCPs film layer after GCIB etching within an area range of 1 μm × 1 μm is measured using AFM to observe the morphological changes and etching depth of the BCPs film layer.

[0065] Figure 4 Schematically shows the morphology diagram of the self-assembled pattern of the block copolymer after etching according to Embodiment 2 of the present disclosure.

[0066] As Figure 4 shown, a is the SEM image, b is the AFM image, c is the size measurement diagram. It can be seen from Figure 5 this that at this time, the height difference between the two-phase interfaces of PS and PLA is less than or equal to 2 nm, the surface of the etched pattern is smooth, and the contrast between the two-phase patterns is good. The etching selectivity ratio of GCIB for the two phases of PS and PLA = 1:2.

[0067] Example 3:

[0068] In Example 3, the method for preparing high-resolution patterns based on gas cluster etching can be as follows:

[0069] (1)Substrate cleaning: In an ultrasonic cleaner, the ITO substrate is successively placed in acetone, ethanol, and deionized water and ultrasonically cleaned for 60 min to remove contaminants on the substrate surface. After cleaning, the substrate is taken out, and the surface liquid is blown dry with nitrogen. Finally, it is placed in an oven for drying to completely remove the residual ITO liquid on the surface;

[0070] (2)Growth of the BCPs film layer: A layer of crosslinkable PS-r-PMMA is spin-coated on the ITO substrate and fully cured to obtain a 5-nm-thick crosslinked film layer. Subsequently, a photoresist is spin-coated and baked to remove the excess solvent. After exposure and development, a grating pattern with a period of 500 nm is obtained. The area not covered by the photoresist is modified using O 2 plasma, and after removing the photoresist, a chemical guiding template is obtained. Subsequently, 25 nm thick PS-b-PDMS is spin-coated on this template, and after thermal annealing, a chemically guided self-assembled pattern is obtained;

[0071] (3)GCIB etching: The high-pressure F 2The gas condenses and expands ultrasonically to form gas clusters with sizes ranging from 50 atoms / ion to 5000 atoms / ion. The gas cluster ions are accelerated through ionization, and the gas clusters with sizes less than 1000 atoms / ion are filtered out using a magnetic mass separator. After screening, the acceleration voltage is adjusted to 20 kV, and high voltage F 2 The pressure of the gas is 5 MPa, the single atomic energy is 4 eV, and clusters with an average size of 5000 atoms / ion are selected to vertically bombard the substrate after BCPs self-assembly;

[0072] (4)Morphology observation: The morphology of the BCPs film layer after GCIB etching within an area range of 1 μm × 1 μm is measured using AFM to observe the morphological changes and etching depth of the BCPs film layer.

[0073] At this time, the height difference between the two-phase interfaces of PS and PDMS is less than or equal to 5 nm, the surface of the etched pattern is smooth, and the contrast between the two-phase patterns is good. The etching selectivity ratio of GCIB for the two phases of PS and PDMS = 1:2.5.

[0074] Example 4:

[0075] In Example 4, the method for preparing high-resolution patterns based on gas cluster etching can be as follows:

[0076] (1)Substrate cleaning: In an ultrasonic cleaning machine, the Si wafer substrate is successively placed in acetone, ethanol, and deionized water and ultrasonically cleaned for 50 min to remove contaminants on the wafer surface. After cleaning, the Si wafer substrate is taken out and the surface liquid is blown dry with nitrogen, and finally placed in an oven for drying to completely remove the residual liquid on the surface;

[0077] (2)Growth of BCPs film layer: A photoresist that preferentially wets the PMMA phase is spin-coated on the PtBS-r-PMMA-OH modified Si wafer. After baking to remove the excess solvent, a physical guiding template with a period of 800 nm is obtained through exposure and development. Subsequently, 15 nm thick PtBS-b-PMMA is spin-coated on this template, and a physical epitaxial pattern is obtained after solvent annealing;

[0078] (3)GCIB etching: The high-pressure Ar gas condenses and expands ultrasonically to form gas clusters with sizes ranging from 50 atoms / ion to 5000 atoms / ion. The gas cluster ions are accelerated through ionization, and the clusters with sizes less than 1000 atoms / ion are filtered out using a magnetic mass separator. After screening, the acceleration voltage is adjusted to 1500 V, the pressure of the high-pressure Ar gas is 20 MPa, the single atomic energy is 1 eV, and clusters with an average size of 1500 atoms / ion are selected to vertically bombard the substrate after BCPs self-assembly;

[0079] (4)Morphology observation: The AFM was used to measure the morphology of the BCPs film after GCIB etching within an area range of 1 μm × 1 μm, and the morphological changes and etching depth of the BCPs film were observed.

[0080] At this time, the height difference between the two-phase interfaces of PtBS and PMMA ≥ 5 nm. After etching, the surface of the pattern was smooth, and the contrast of the two-phase pattern was excellent. The etching selectivity ratio of GCIB for the two phases of PtBS and PMMA = 1:5.

[0081] Example 5:

[0082] In Example 5, the method for preparing high-resolution patterns based on gas cluster etching can be as follows:

[0083] (1)Substrate cleaning: In an ultrasonic cleaning machine, the Si wafer substrate was successively placed in acetone, ethanol, and deionized water and ultrasonically cleaned for 30 min to remove the contaminants on the wafer surface. After cleaning, the Si wafer substrate was taken out, and the surface liquid was blown dry with nitrogen. Finally, it was put into an oven for drying to completely remove the residual liquid on the surface;

[0084] (2)Growth of BCPs film layer: A layer of crosslinkable polystyrene was spin-coated on the wafer with Si-BARC deposited on the surface and fully cured to obtain a 5-nm-thick crosslinked film layer. Subsequently, a photoresist was spin-coated and baked to remove the excess solvent. After exposure and development, a grating pattern with a period of 500 nm was obtained. The area not covered by the photoresist was transferred to the Si-BARC layer by O 2 plasma. The residual photoresist was washed off, and a chemical guiding template was obtained after PS-r-PMMA-OH modification. Subsequently, 25 nm thick PS-b-PLGA was spin-coated on this template, and a chemically epitaxial pattern was obtained after thermal annealing;

[0085] (3)GCIB etching: The high-pressure O 2 gas was condensed and ultrasonically expanded to form gas clusters with a size between 50 atoms / ion and 5000 atoms / ion. The gas cluster ions were accelerated by ionization, and the clusters with a size less than 1000 atoms / ion were filtered out by a magnetic mass separator. After screening, the acceleration voltage was adjusted to 4 kV, the pressure of the high-pressure O 2 gas was 1 MPa, the single atomic energy was 2 eV, and the clusters with an average size of 2000 atoms / ion were selected to vertically bombard the substrate after BCPs self-assembly;

[0086] (4)Morphology observation: AFM was used to measure the morphology of the BCPs film after GCIB etching within an area range of 1 μm × 1 μm, and the morphological changes and etching depth of the BCPs film were observed. At this time, the height difference between the PS and PLGA two-phase interfaces was ≥5 nm, the surface of the etched pattern was smooth, and the contrast of the two-phase pattern was good. The etching selectivity ratio of GCIB for the PS and PLGA two phases was 1:3.

[0087] Comparative Example 1:

[0088] In Comparative Example 1, the method for preparing a high-resolution pattern can be as follows:

[0089] (1)Substrate cleaning: In an ultrasonic cleaning machine, the Si wafer substrate was successively placed in acetone, ethanol, and deionized water for ultrasonic cleaning for 30 min to remove the contaminants on the wafer surface. After the cleaning was completed, the Si wafer substrate was taken out, and the surface liquid was blown dry with nitrogen. Finally, it was placed in an oven for drying to completely remove the residual surface liquid;

[0090] (2)Growth of BCPs film layer: PS-b-PMMA was spin-coated on the PS-r-PMMA-OH modified Si wafer to form a 20-nm-thick block copolymer film layer. After thermal annealing, an unoriented self-assembled pattern was obtained;

[0091] (3)Morphology observation: AFM was used to measure the morphology of the unetched BCPs film within an area range of 1 μm × 1 μm, and the morphology of the BCPs film was observed.

[0092] Figure 5 Schematically shows the morphology diagram of the etched block copolymer self-assembled pattern according to Comparative Example 1 of the present disclosure.

[0093] As Figure 5 shown, a is the SEM image, b is the AFM image, and c is the size measurement image. It can be seen from Figure 5 that at this time, the height difference between the PS and PMMA two-phase interfaces was less than or equal to 1 nm, the surface of the original BCPs pattern was rough, and the contrast of the two-phase pattern was poor.

[0094] Comparative Example 2:

[0095] In Comparative Example 2, the method for preparing a high-resolution pattern can be as follows:

[0096] (1)Substrate cleaning: In an ultrasonic cleaning machine, the Si wafer substrate was successively placed in acetone, ethanol, and deionized water for ultrasonic cleaning for 50 min to remove the contaminants on the wafer surface. After the cleaning was completed, the Si wafer substrate was taken out, and the surface liquid was blown dry with nitrogen. Finally, it was placed in an oven for drying to completely remove the residual surface liquid;

[0097] (2)BCP film growth: Spin-coat a layer of crosslinkable polystyrene on the wafer with an SOC layer deposited on its surface and fully cure it to obtain a 5-nm-thick crosslinked polystyrene film layer. Subsequently, spin-coat a photoresist and bake it to remove the excess solvent. After exposure and development, a grating pattern with a period of 400 nm is obtained. Modify the area not covered by the photoresist with O 2 plasma. After removing the photoresist, a chemical guiding template is obtained. Spin-coat 30 nm thick PMOST-b-PTMSS on this template and obtain a chemically epitaxial pattern after solvent annealing;

[0098] (3)GCIB etching: Condense high-pressure Ar gas and ultrasonically expand it to form gas clusters with a size between 50 atoms / ion and 5000 atoms / ion. Accelerate the cluster ions by ionization and filter out the clusters with a size less than 1000 atoms / ion using a magnetic mass separator. After screening, adjust the acceleration voltage to 60 kV, the pressure of high-pressure Ar gas to 100 MPa, the single atomic energy to 6 eV, and select clusters with an average size of 10000 atoms / ion to vertically bombard the substrate after BCPs self-assembly;

[0099] (4)Morphology observation: Use AFM to measure the morphology of the BCP film layer after GCIB etching within an area range of 1 μm × 1 μm, and observe the morphological changes and etching depth of the BCP film layer. At this time, the height difference between the PMOST and PTMSS two-phase interfaces ≤ 1 nm, the surface of the etched pattern is smooth, and the contrast of the two-phase pattern is average. The etching selectivity ratio of GCIB for the PMOST and PTMSS two phases = 1:1.2.

[0100] Comparative example 3:

[0101] In Comparative example 3, the method for preparing a high-resolution pattern can be as follows:

[0102] (1)Substrate cleaning: In an ultrasonic cleaning machine, place the SiO 2 substrate in acetone, ethanol, and deionized water in sequence and ultrasonically clean it for 40 min to remove the contaminants on the substrate surface. After cleaning, take out the SiO 2 substrate and dry the surface liquid with nitrogen. Finally, put it in an oven for drying to completely remove the residual liquid on the surface;

[0103] (2)BCP film growth: Spin-coat a photoresist that preferentially wets the PS phase on the SiO 2 substrate modified with PS-r-PGM-OH. After baking to remove the excess solvent, obtain a physical guiding template with a period of 200 nm through exposure and development. Subsequently, spin-coat 30 nm thick PS-b-PGM on this template and obtain a physically epitaxial pattern after solvent annealing;

[0104] (3)GCIB etching: High-pressure Br 2 gas condenses and undergoes ultrasonic expansion to form gas clusters with sizes ranging from 50 to 5000 atoms / ion. The cluster ions are accelerated through ionization, and clusters with sizes less than 1000 atoms / ion are filtered out using a magnetic mass separator. After screening, the acceleration voltage is adjusted to 60 kV, and the high-pressure Br 2 gas has a pressure of 5 MPa, a single atomic energy of 30 eV, and clusters with an average size of 2000 atoms / ion are selected to vertically bombard the substrate after the self-assembly of BCPs;

[0105] (4)Morphology observation: AFM is used to measure the morphology of the BCPs film layer after GCIB etching within an area range of 1 μm × 1 μm, and the morphological changes and etching depth of the BCPs film layer are observed. At this time, the height difference between the two-phase interfaces of PS and PGM is less than or equal to 1 nm, the surface of the etched pattern is smooth, and the contrast of the two-phase pattern is average. The etching selectivity ratio of GCIB for the two phases of PS and PGM = 1:1.

[0106] Table 3 Comparison of the preparation processes and results corresponding to the examples and comparative examples

[0107]

[0108] Based on Table 3, combined with the foregoing examples and comparative examples, it can be intuitively seen that by using the method for preparing high-resolution patterns based on gas cluster etching in the embodiments of the present disclosure, the pattern contrast of the obtained high-resolution images is better than that of the resolution images prepared by the existing methods.

[0109] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present disclosure. It should be understood that the above are only the preferred embodiments of the present disclosure and the technical principles applied. Those skilled in the art will understand that the present disclosure is not limited to the specific embodiments described herein. Various obvious changes, re-adjustments, and substitutions can be made by those skilled in the art without departing from the protection scope of the present disclosure. Therefore, although the present disclosure has been described in more detail through the above embodiments, the present disclosure is not limited to the above embodiments. Without departing from the concept of the present disclosure, more other equivalent embodiments can be included, all of which fall within the protection scope of the present disclosure.

Claims

1. A method for preparing high-resolution patterns based on gas cluster etching, characterized in that: include: A block copolymer film layer having a vertical structure epitaxial pattern is prepared on the surface of a substrate by using a block copolymer; Using etching gas to prepare gas cluster ion beam; The gas cluster ion beam is used to bombard the block copolymer film layer with the vertical structure epitaxial pattern, and the block copolymer film layer is selectively etched to form a high-resolution pattern.

2. The method according to claim 1, characterized in that The method of preparing a gas cluster ion beam by using an etching gas comprises: Condensing and ultrasonically expanding a high-pressure gas containing at least one etching gas to form clusters having a size within an initial size range; The clusters with a size within the initial size range are accelerated by ionization, and clusters with a size smaller than a size threshold are filtered out by a magnetic mass separator to obtain clusters with a size within the target size range.

3. The method according to claim 2, characterized in that The etching gas includes at least one of Ar, O2, F2, Cl2, Br2 and halides and alkyl halides corresponding to Ar, O2, F2, Cl2 and Br2; The initial size range is 50 atoms / ion to 5000 atoms / ion, the size threshold is 1000 atoms / ion, and the initial size range is 1000 atoms / ion to 5000 atoms / ion.

4. The method according to any one of claims 2 or 3, characterized in that: The gas cluster ion beam is used to vertically bombard the block copolymer film layer having a vertical structure epitaxial pattern, wherein the pressure of the high-pressure gas is 1 MPa to 100 MPa, the acceleration voltage is 500 V to 30 kV, and the ionization energy of a single atom is 0.5 eV to 10 eV.

5. The method according to claim 1, characterized in that The vertical structure epitaxial pattern of the block copolymer film layer includes a physical epitaxial pattern, and the block copolymer film layer having a vertical structure epitaxial pattern is prepared on the surface of the substrate using the block copolymer, comprising: The block copolymer is coated on a substrate having undulations and composed of a photoresist or an etching pattern, and annealed to form the physical epitaxial pattern.

6. The method according to claim 1, characterized in that The vertical structure epitaxial pattern of the block copolymer film layer includes a chemical epitaxial pattern, and the block copolymer film layer having a vertical structure epitaxial pattern is prepared on the surface of the substrate using the block copolymer, comprising: The block copolymer is coated on a flat pattern substrate composed of alternating chemical components and annealed to form the chemical epitaxial pattern.

7. The method according to claim 1, characterized in that The vertical structure epitaxial pattern of the block copolymer film layer includes an unguided self-assembly pattern, and the block copolymer film layer having the vertical structure epitaxial pattern is prepared on the surface of the substrate using the block copolymer, comprising: The block copolymer is coated on a flat pattern substrate composed of a single chemical component and annealed to form the unguided self-assembly pattern.

8. The method according to claim 5 or 6, characterized in that: The annealing temperature corresponding to the block copolymer film layer is 50°C~250°C, the annealing time is 0.5 h~48 h, the annealing corresponding to the block copolymer film layer is carried out in a nitrogen atmosphere or an organic solvent vapor atmosphere, and the organic solvent includes at least one of acetone, tetrahydrofuran, and N,N-dimethylformamide; the thickness of the block copolymer film layer is 10 nm~50 nm.

9. The method according to claim 1, characterized in that: The block copolymers include polystyrene-b-polymethyl methacrylate, polystyrene-b-polyisoprene, polystyrene-b-polylactic acid, polystyrene-b-polydimethylsiloxane, polystyrene-b-polytrimethylene carbonate, polystyrene-b-poly(2-vinylpyridine), polystyrene-b-polypropylene carbonate, poly(4-tert-butylstyrene)-b-polymethyl methacrylate, polystyrene-b-polyacrylic acid acetonate, polystyrene-b-polylactic acid glycolate, polystyrene-b-polymethyl acrylate, polystyrene-b-polymethacrylic acid acetonate, polystyrene-b-poly(4-hydroxystyrene), polystyrene-b-poly(4-vinylpyridine), polystyrene-b-poly(ethyl 2,2,2-trifluoroacrylate), poly(4-tert-butylstyrene) -b-poly(2-vinylpyridine), polyvinylcyclohexane-b-polymethyl methacrylate, polydimethylsiloxane-b-polymethyl methacrylate, polystyrene-b-polypentadecafluorooctyl methacrylate, polystyrene-b-polyhydroxyisobutylene, polystyrene-b-polyacrylic acid, polystyrene-b-poly(3,4-dihydroxystyrene), poly(4-trimethylsilylstyrene)-b-polylactic acid, polystyrene-b-poly(2,3-dihydroxypropyl methacrylate), poly(2-vinylpyridine)-b-poly(heptafluorobutyl-2-methylprop-2-enoate), poly(3-hydroxystyrene)-b-polydimethylsiloxane.

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