Method for preventing photoresist denaturation in process of etching graphene by oxygen plasma based on isolating layer

Abstract

The invention belongs to the field of semiconductor processes and devices, and particularly relates to a method for preventing photoresist denaturation in the process of etching graphene by oxygen plasma based on an isolating layer. The method comprises the following steps: transferring graphene to a substrate through a mechanical stripping and transferring technology; exposing the two ends of the graphene in the environment through photoetching, and evaporating Se serving as an isolating layer onto the developed graphene pattern; covering photoresist to protect Se from being influenced by subsequent etching, and performing photoetching to form a graphene channel; processing the graphene substrate covered by the photoresist by adopting oxygen plasma, and etching a graphene channel; and annealing to remove Se. The method is suitable for manufacturing semiconductor devices, and has wide application prospects in the fields of micromachining, patterning and functionalization treatment of graphene-based materials. The method can be used for preparation processes of graphene integrated circuits, graphene sensors, photoelectric devices and other microelectronic devices, and especially has a promotion effect on high-precision graphene processing.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor technology and devices, and in particular relates to a method for preventing photoresist denaturation in the process of etching graphene with oxygen plasma based on an isolation layer. Background Art

[0002] Graphene is a new type of carbon structure discovered after fullerene and carbon nanotubes. 2 Hybridized carbon atoms are arranged in a hexagonal lattice to form a honeycomb lattice structure, which is a two-dimensional material in the strict sense. Since it was first reported in 2004, graphene has rapidly emerged in the fields of physics and materials science, becoming an important material for basic scientific research and emerging technology development. Its unique two-dimensional quantum system characteristics have overturned the traditional theory that two-dimensional crystals cannot exist stably. In particular, the transport characteristics of zero-mass Dirac fermions enable it to have extremely high carrier mobility, room temperature quantum Hall effect and micrometer-scale electron coherence, which has brought revolutionary breakthroughs to the development of condensed matter physics. At the same time, it has shown broad application prospects in the fields of micro-nanoelectronic devices, high-performance batteries, gas sensors and terahertz technology.

[0003] However, the intrinsic zero bandgap characteristics of graphene limit its application in logic circuits and transistor devices, so introducing a bandgap and regulating its physical properties have become the focus of scientific research. To solve this problem, scientists have proposed a variety of methods: using an external electric field or chemical potential field to achieve Landau level splitting in double-layer graphene to introduce symmetry breaking, which is an effective means of regulating the bandgap; constructing structures such as graphene nanoribbons through quantum confinement effects, and using bandwidth adjustment to achieve precise control of the bandgap; using chemical vapor deposition technology, through the doping of elements such as B and N, introducing an energy gap in graphene and adjusting its size; using epitaxial growth on silicon carbide substrates, achieving energy gap modulation through substrate-induced effects. These methods provide a variety of possibilities for overcoming the limitations of graphene in logic devices, but to achieve high-quality graphene patterning, the processing process needs to have size controllability, specific directionality, and atomically smooth edges, which places higher requirements on the etching and cutting of graphene.

[0004] At present, there are three common processing methods for graphene surface etching and patterning: graphic exposure etching, chemical cutting and probe technology. Among them, graphic exposure etching of graphene uses PMMA mask for electron beam exposure and oxygen plasma etching, but the etching edge roughness is large (>5nm); chemical cutting is to prepare graphene nanoribbons by chemical methods, which can achieve the effect of edge roughness less than 5nm. Although the edge is smoother, the size is difficult to control and impurities may be introduced. Although in 2009, researchers from the Institute of Metal Research, Chinese Academy of Sciences proposed a method for chemical cutting of graphene to prepare graphene ribbons in large quantities, the cutting accuracy is still limited due to its reliance on ultrasonic shearing and chemical reduction. Removing large pieces of graphene that have not been completely cut may face problems of low efficiency and high cost, and may cause some graphene ribbons that do not meet the requirements to be mistakenly retained. In comparison, the probe technology uses scanning tunneling microscope probes or atomic force microscope anodizing technology for etching, which has high precision but low efficiency and is not suitable for large-scale applications. For example, in 2018, Chen Jianmei of Soochow University published a paper on polymer surface patterning and application based on atomic force probe etching technology. The scanning probe processing technology optimizes the etching accuracy, but large-scale integrated production is affected by cost.

[0005] In summary, although the surface etching processing methods of graphene have their own characteristics, they generally have limitations. In contrast, the graphic exposure etching method can achieve precise size control and highly customizable pattern processing, and has greater potential in high-precision and large-scale processing, and has significant advantages. However, oxygen plasma etching can easily denature the photoresist, and the denatured photoresist will remain in the etching channel and is difficult to wash off. If this problem can be solved, the application range of graphic exposure etching in semiconductor process manufacturing will be wider. Summary of the invention

[0006] During the process of etching graphene with oxygen plasma, the photoresist is exposed to high-energy ions and active oxygen atoms, which can easily cause chemical reactions and lead to the denaturation of the photoresist. The denaturation and degradation of the photoresist will affect the etching accuracy, edge quality and surface cleanliness of graphene.

[0007] In order to solve the above-mentioned technical problems, this application provides the following technical solutions:

[0008] In order to solve the problem of denaturation of photoresist during plasma etching, the present invention introduces an isolation layer between photoresist and graphene, and combines a mild plasma etching technology to propose a new method. The method effectively controls the contact between photoresist and graphene to prevent the photoresist from being damaged during the etching process, thereby improving the patterning quality of graphene. The special feature is that by using an isolation layer to protect the photoresist, the denaturation of the photoresist is avoided, and the integrity of the graphene during the etching process is ensured. The method is simple to operate, low in cost, and can achieve high-precision graphene processing, and is widely used in the preparation of high-performance graphene devices.

[0009] The present invention provides a method for preventing photoresist denaturation during graphene etching by oxygen plasma based on an isolation layer, comprising the following steps:

[0010] S11: transferring the graphene film to the surface of the substrate to obtain a substrate with graphene;

[0011] S12: coating a photoresist on the substrate with graphene, baking, photolithography and developing, to form a photoresist mask containing a pattern;

[0012] S13: vapor-depositing selenium (Se) at the pattern of the photoresist mask and then washing away the photoresist to form a sample; the sample includes a groove I not covered by selenium and a selenium isolation layer for protecting graphene;

[0013] S14: coating the surface of the sample in step S13 with photoresist, baking, photolithography and developing, forming groove II, and obtaining graphene after secondary development; the groove II includes the groove I not covered by selenium;

[0014] S15: etching the graphene after the secondary development using oxygen plasma to obtain graphene after plasma etching;

[0015] S16: washing the photoresist from the graphene after the plasma etching and then annealing to obtain the graphene channel based on the isolation layer to prevent the photoresist from being denatured during the oxygen plasma etching process.

[0016] Preferably, in step S11, the substrate is a silicon-based substrate, and before the transfer, it is ultrasonically cleaned in acetone, ethanol and water, dried and baked in sequence to remove residues such as acetone and ethanol.

[0017] Furthermore, the frequency of the ultrasonic cleaning is 20-25kHz.

[0018] Specifically, in step S11, before the substrate is transferred, the silicon-based substrate is first placed in acetone and ultrasonically cleaned for 4 to 6 minutes; then the silicon-based substrate is placed in ethanol and ultrasonically cleaned for 4 to 6 minutes; then, the silicon-based substrate is ultrasonically cleaned in deionized water for 4 to 6 minutes, then blown dry with a nitrogen gun, and finally baked on a heating platform at 300±10°C for 9 to 10 minutes.

[0019] Preferably, the model of the photoresist is AZ5214E.

[0020] Preferably, the thickness of the graphene film is 5-10 nm.

[0021] Preferably, in step S11, the graphene film is transferred by a PDMS dry transfer method.

[0022] Preferably, in step S12, the method of coating the photoresist is: spin coating at a rotation speed of 580-620 rpm for 9-10 s, and spin coating at a rotation speed of 2970-3030 rpm for 25-35 s.

[0023] Preferably, in step S12, the baking temperature is 100° C. and the baking time is 90 seconds.

[0024] Preferably, in step S12, the method of photolithography and development is: placing the graphene on a maskless lithography machine stage, aligning the groove I to be protected under a microscope, blocking it, and exposing the remaining areas of the sample to ensure that the photoresist can be removed from these areas in a subsequent development step, thereby forming a photoresist mask on the graphene sample to protect the channel area, and the remaining areas are exposed.

[0025] Preferably, the width of the groove I is 9.5-10.5 μm.

[0026] Preferably, in step S13, the method for evaporating selenium is thermal evaporation; during thermal evaporation, the vacuum condition of the evaporator is 1×10 -4 Pa below, the evaporation rate is The time is 30 min, and the obtained material thickness is 50 nm, so the part not protected by the photoresist mask in the step is covered with Se to act as a protective layer.

[0027] Preferably, in step S14, the developer used in the photolithography development is a mixture of an aqueous solution containing 25 wt % tetramethylammonium hydroxide and water, with a volume ratio of 25:3.

[0028] Preferably, in step S15, the purity of oxygen in the oxygen plasma is 5N and the gas flow rate is 20 sccm.

[0029] Preferably, in step S16, the annealing temperature is 250-300° C., the time is 5-6 hours, and the Se isolation layer disappears after annealing.

[0030] The present invention also provides a graphene channel prepared by the above method.

[0031] Preferably, a thin layer of In2Se3 is transferred onto the graphene channel, and a gold electrode is evaporated onto the graphene to obtain a complete device and test the output characteristic curve.

[0032] Furthermore, the method for transferring the In2Se3 thin layer is dry transfer; when thermally evaporating gold, the vacuum condition of the evaporator is 1×10 -4 Pa below, the evaporation rate is The time is 30 minutes, and the obtained material thickness is 50nm, so as to obtain a complete device in order to test the output characteristic curve and verify the feasibility of the method.

[0033] The technical solution of the present invention has the following advantages compared with the prior art:

[0034] (1) The present invention can accurately form grooves and isolation layers on the graphene surface through a multi-step process combining photolithography, evaporation and plasma etching, effectively preventing damage or denaturation of the graphene during oxygen plasma etching and ensuring the structural integrity of the graphene.

[0035] (2) The present invention adopts a design of a photoresist mask and evaporated selenium as a protective layer, which can accurately control the area to be etched and avoid the denaturation of the photoresist in subsequent steps, thereby ensuring high-precision processing of the graphene channel area and being suitable for the preparation of high-performance devices.

[0036] (3) The present invention avoids the adverse degeneration of the photoresist during plasma etching by precisely controlling the processing conditions of the photoresist and adopting appropriate annealing and etching processes, thereby ensuring the protective effect of the photoresist on graphene and enhancing the selectivity and stability of the photoresist.

[0037] (4) The present invention can effectively protect the edge structure of graphene during the etching process by introducing steps such as a Se protective layer and oxygen plasma etching, so that the groove area of ​​the graphene maintains atomic-level flatness, avoids edge contamination and damage, and improves the quality of the graphene material.

[0038] (5) The method of the present invention has a simple process and is easy to operate, and can complete the processing and patterning of graphene in a relatively short time. It is suitable for large-scale production and practical applications, thereby improving production efficiency and reducing processing costs.

[0039] (6) The present invention can be used to effectively prevent photoresist denaturation in graphene etching, and can also be used for other two-dimensional materials that are etched using oxygen plasma. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The figure is a schematic diagram of the process and application of oxygen plasma etching graphene based on the Se isolation layer prepared in Example 1;

[0041] Figure 2 This is a light microscope image of graphene being evaporated with Se and etched with oxygen plasma in Example 1;

[0042] Figure 3 is a light microscope schematic diagram of graphene after annealing in Example 1;

[0043] Figure 4 This is a graph showing the output characteristics of the etched graphene after the gold electrode is evaporated and In2Se3 is transferred;

[0044] Figure 5 This is an optical microscopy image of the result of oxygen plasma etching graphene without isolation layer prepared in Comparative Example 1. DETAILED DESCRIPTION

[0045] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0046] The graphene film is prepared by a mechanical stripping method. The specific steps are: first use blue glue to stick part of the sample on the surface of the graphene crystal, and then tear the tapes apart from each other. Repeat this process about ten times. When the sample left on the tape turns gray, the graphene film is obtained.

[0047] PDMS dry transfer technology: stick the tape containing graphene on the PDMS surface, let it stand for 1 hour and then peel off the tape, leaving the graphene sample on the surface of polydimethylsiloxane (PDMS); then stick the treated silicon-based substrate on the PDMS surface, let it stand for another 30 minutes and then peel off the silicon-based substrate, and the graphene sample will be transferred to the substrate surface;

[0048] The PDMS substrate used was self-prepared. When preparing, Dow Corning SYLGARD 184 silicone rubber and curing agent were first mixed in a weight ratio of 10:1, stirred evenly, and then placed in a refrigerator (4°C) for 48 hours to solidify into a transparent film.

[0049] The selenium prepared by thermal evaporation; the vacuum condition of the evaporation machine must meet 1×10 -3 Pa below, the evaporation rate used is The time is about 25 minutes, and the thickness of the obtained electrode material is 50 nm.

[0050] The In2Se3 film was prepared by mechanical stripping. The specific steps were as follows: first, use blue glue to stick part of the sample on the surface of the In2Se3 crystal, then tear the tapes apart from each other, and repeat this process about ten times. When the sample left on the tapes appears gray, the In2Se3 film is obtained.

[0051] In2Se3 dry transfer operation: stick the tape containing In2Se3 on the PDMS surface, let it stand for 1 hour, then peel off the tape, leaving the graphene sample on the polydimethylsiloxane (PDMS) surface; accurately observe the PDMS surface and the graphene sample on the silicon substrate through an optical microscope to ensure that the thin layer of In2Se3 is accurately aligned with the graphene surface. After alignment, heat the PDMS sample and the graphene sample to 70°C together, so that the In2Se3 thin layer is fully in contact and fit with the graphene surface, and gently apply pressure to make the thin layer firmly adhere to the graphene to complete the transfer.

[0052] The gold prepared by thermal evaporation; the vacuum condition of the evaporator must meet 1×10 -3 Pa below, the evaporation rate used is The time is about 25 minutes, and the thickness of the obtained electrode material is 50 nm.

[0053] Example 1

[0054] This embodiment provides a method for preventing photoresist from being denatured during the process of etching graphene with oxygen plasma based on an isolation layer. The process is as follows: Figure 1 , the steps are as follows:

[0055] (1) First, the silicon-based substrate was placed in acetone and ultrasonically cleaned for 5 minutes; then, the silicon-based substrate was placed in ethanol and ultrasonically cleaned for 5 minutes; then, the silicon-based substrate was ultrasonically cleaned in deionized water for 5 minutes, then dried with a nitrogen gun, and finally baked on a heating platform at 300° C. for 10 minutes;

[0056] (2) obtaining a few-layer graphene film by mechanical exfoliation technology, and transferring it to the surface of the substrate cleaned in step (1) by PDMS dry transfer technology to obtain a substrate with graphene;

[0057] (3) Spin-coat the photoresist uniformly on the substrate with graphene prepared in step (2) at a spin-coating speed of 600 rpm for 10 s and 3000 rpm for 30 s, then bake, place the graphene on a maskless photolithography stage, align the channel area to be protected under a microscope, block it, and keep its width at 10±0.5 μm. Expose the remaining areas of the sample to ensure that the photoresist can be removed in the subsequent development step, thereby forming a photoresist mask protecting the channel area on the graphene sample, and leaving the remaining areas bare.

[0058] (4) Placing the graphene developed in step (3) in a vapor deposition machine to vapor deposit Se under a vacuum condition of 1×10 - 3 Pa below, the evaporation rate used is The time is 30 minutes, and the thickness of the obtained electrode material is 50 nm. The photoresist is washed away to obtain the groove not covered by selenium. The groove is the area to be etched later, and the remaining area covered by selenium is the isolation layer to protect the graphene;

[0059] (5) Spin-coating the graphene after the evaporation treatment in step (4) with photoresist again and baking, the grooves obtained after the photolithography and development are exposed to the environment (Se is on the grooves), and the remaining parts are isolated from the environment with photoresist;

[0060] (6) placing the photolithographic graphene with Se as a buffer layer in step (5) into a mild plasma reaction chamber, and etching the exposed graphene channel using O2 plasma. The area covered by the photoresist will not change, and the Se on the channel will also be etched away by oxygen plasma, thereby obtaining plasma-etched graphene;

[0061] (7) After the graphene etched in step (6) is washed to remove the photoresist, it is annealed at 275° C. for 5 h to remove the Se layer, thereby obtaining an O2 plasma-etched graphene channel without any denatured photoresist residue.

[0062] (8) Transferring an In2Se3 thin layer onto the graphene channel after annealing in step (7), evaporating a gold electrode on the graphene, obtaining a complete device and testing the output characteristic curve.

[0063] The etched graphene obtained in step (6) is observed under a light microscope, and the results are as follows: Figure 2 The annealed graphene obtained in step (7) is observed under a light microscope, and the results are as follows: Figure 3 The result obtained in step (8) is as follows: Figure 4 shown.

[0064] Example 2

[0065] This embodiment provides a method for preventing photoresist from being denatured during the process of etching graphene with oxygen plasma based on an isolation layer. The process is as follows: Figure 1 , the steps are as follows:

[0066] (1) First, the silicon-based substrate was placed in acetone and ultrasonically cleaned for 4 minutes; then, the silicon-based substrate was placed in ethanol and ultrasonically cleaned for 4 minutes; then, the silicon-based substrate was ultrasonically cleaned in deionized water for 4 minutes, then dried with a nitrogen gun, and finally baked on a heating platform at 290° C. for 9 minutes;

[0067] (2) obtaining a few-layer graphene film by mechanical exfoliation technology, and transferring it to the surface of the substrate cleaned in step (1) by PDMS dry transfer technology to obtain a substrate with graphene;

[0068] (3) Spin-coat the photoresist uniformly on the substrate with graphene prepared in step (2) at a spin-coating speed of 580 rpm for 9 s and 2970 rpm for 25 s, then bake, place the graphene on the stage of the maskless photolithography machine, align the channel area to be protected under a microscope, block it, and keep its width at 10±0.5 μm. Expose the remaining areas of the sample to ensure that the photoresist can be removed in the subsequent development step, thereby forming a photoresist mask protecting the channel area on the graphene sample, and leaving the remaining areas bare.

[0069] (4) Placing the graphene developed in step (3) in a vapor deposition machine to vapor deposit Se under a vacuum condition of 1×10 - 3 Pa below, the evaporation rate used is The time is 30 minutes, and the thickness of the obtained electrode material is 50 nm. The photoresist is washed away to obtain the groove not covered by selenium. The groove is the area to be etched later, and the remaining area covered by selenium is the isolation layer to protect the graphene;

[0070] (5) Spin-coating the graphene after the evaporation treatment in step (4) with photoresist again and baking, the grooves obtained after the photolithography and development are exposed to the environment (Se is on the grooves), and the remaining parts are isolated from the environment with photoresist;

[0071] (6) placing the photolithographic graphene with Se as a buffer layer in step (5) into a mild plasma reaction chamber, and etching the exposed graphene channel using O2 plasma. The area covered by the photoresist will not change, and the Se on the channel will also be etched away by oxygen plasma, thereby obtaining plasma-etched graphene;

[0072] (7) After the graphene etched in step (6) is washed to remove the photoresist, it is annealed at 250° C. for 5 h to remove the Se layer, thereby obtaining an O2 plasma-etched graphene channel without any denatured photoresist residue.

[0073] Example 3

[0074] This embodiment provides a method for preventing photoresist from being denatured during the process of etching graphene with oxygen plasma based on an isolation layer. The process is as follows: Figure 1 , the steps are as follows:

[0075] (1) First, the silicon-based substrate was placed in acetone and ultrasonically cleaned for 6 minutes; then, the silicon-based substrate was placed in ethanol and ultrasonically cleaned for 6 minutes; then, the silicon-based substrate was ultrasonically cleaned in deionized water for 6 minutes, then dried with a nitrogen gun, and finally baked on a heating platform at 310° C. for 10 minutes;

[0076] (2) obtaining a few-layer graphene film by mechanical exfoliation technology, and transferring it to the surface of the substrate cleaned in step (1) by PDMS dry transfer technology to obtain a substrate with graphene;

[0077] (3) Spin-coat the photoresist uniformly on the substrate with graphene prepared in step (2) at a spin-coating speed of 620 rpm for 10 s and 3030 rpm for 35 s, then bake, place the graphene on the stage of the maskless photolithography machine, align the channel area to be protected under a microscope, block it, and keep its width at 10±0.5 μm. Expose the remaining areas of the sample to ensure that the photoresist can be removed in the subsequent development step, thereby forming a photoresist mask protecting the channel area on the graphene sample, and leaving the remaining areas bare.

[0078] (4) Placing the graphene developed in step (3) in a vapor deposition machine to vapor deposit Se under a vacuum condition of 1×10 - 3 Pa below, the evaporation rate used is The time is 30 minutes, and the thickness of the obtained electrode material is 50 nm. The photoresist is washed away to obtain the groove not covered by selenium. The groove is the area to be etched later, and the remaining area covered by selenium is the isolation layer to protect the graphene;

[0079] (5) Spin-coating the graphene after the evaporation treatment in step (4) with photoresist again and baking, the grooves obtained after the photolithography and development are exposed to the environment (Se is on the grooves), and the remaining parts are isolated from the environment with photoresist;

[0080] (6) placing the photolithographic graphene with Se as a buffer layer in step (5) into a mild plasma reaction chamber, and etching the exposed graphene channel using O2 plasma. The area covered by the photoresist will not change, and the Se on the channel will also be etched away by oxygen plasma, thereby obtaining plasma-etched graphene;

[0081] (7) After the graphene etched in step (6) is washed to remove the photoresist, it is annealed at 300° C. for 6 h to remove the Se layer, thereby obtaining an O2 plasma-etched graphene channel without any denatured photoresist residue.

[0082] Comparative Example 1

[0083] Referring to Example 1, the steps of preparing the Se isolation layer in the example are omitted, that is, Se is not evaporated before etching the channel, and the rest is consistent with the example, and the graphene after the original etching method is obtained. Figure 5 As shown in the figure, it can be seen that after the oxygen plasma etching of graphene without isolation layer, the denatured photoresist will remain in the etched channel, especially when the parameters are not accurately controlled during the etching process, it will cover the entire material. Figure 5 As shown in FIG. 1 , the quality and performance of the final product are affected, while the graphene with an isolation layer to prevent the photoresist from being denatured during the oxygen plasma etching process can still be made into Figure 4 A complete device with good output characteristics.

[0084] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A method for preventing photoresist denaturation during graphene etching by oxygen plasma based on an isolation layer, characterized in that: The steps include: S11: transferring the graphene film to the surface of the substrate to obtain a substrate with graphene; S12: coating a photoresist on the substrate with graphene, baking, photolithography and developing, to form a photoresist mask containing a pattern; S13: vapor-depositing selenium at the pattern of the photoresist mask and then washing away the photoresist to form a sample; The sample comprises a groove I not covered by selenium and a selenium isolation layer protecting graphene; S14: coating the surface of the sample in step S13 with photoresist, baking, photolithography and developing, forming groove II, and obtaining graphene after secondary development; the groove II includes the groove I not covered by selenium; S15: etching the graphene after the secondary development using oxygen plasma to obtain graphene after plasma etching; S16: washing the photoresist off the graphene after the plasma etching and then annealing to obtain a graphene channel based on the isolation layer to prevent the photoresist from being denatured during the oxygen plasma etching process.

2. The method for preventing photoresist denaturation during graphene etching by oxygen plasma based on an isolation layer as claimed in claim 1, characterized in that: In the step S11, the substrate is a silicon-based substrate, which is ultrasonically cleaned in acetone, ethanol and water, dried and baked in sequence before transfer.

3. The method for preventing photoresist denaturation during graphene etching by oxygen plasma based on an isolation layer as claimed in claim 1, characterized in that: In the step S11, the graphene film is transferred by a PDMS dry transfer method.

4. The method for preventing photoresist denaturation during graphene etching by oxygen plasma based on an isolation layer as claimed in claim 1, characterized in that: In the step S12, the method of coating the photoresist is: spin coating at a rotation speed of 580-620 rpm for 9-10 s, and spin coating at a rotation speed of 2970-3030 rpm for 25-35 s.

5. The method for preventing photoresist denaturation during graphene etching by oxygen plasma based on an isolation layer as claimed in claim 1, characterized in that: In the step S12, the method of photolithography development is: placing the graphene on a maskless photolithography stage, aligning the groove I to be protected under a microscope, shielding it, and exposing the remaining areas of the sample.

6. The method for preventing photoresist denaturation during graphene etching by oxygen plasma based on an isolation layer as claimed in claim 1, characterized in that: The width of the groove I is 9.5-10.5 μm.

7. The method for preventing photoresist denaturation during graphene etching by oxygen plasma based on an isolation layer as claimed in claim 1, characterized in that: In step S13, the method for evaporating selenium is thermal evaporation; during thermal evaporation, the vacuum condition of the evaporator is 1×10 -4 Pa below, the evaporation rate is The time was 30 min and the obtained material thickness was 50 nm.

8. The method for preventing photoresist denaturation during graphene etching by oxygen plasma based on an isolation layer as claimed in claim 1, characterized in that: In the step S14, the developer used in the photolithography development is a mixture of an aqueous solution containing 25 wt % tetramethylammonium hydroxide and water, and the volume ratio of the two is 25:

3.

9. The method for preventing photoresist denaturation during graphene etching by oxygen plasma based on an isolation layer as claimed in claim 1, characterized in that: In the step S16, the annealing temperature is 250-300° C. and the annealing time is 5-6 hours.

10. A graphene channel prepared by the method according to any one of claims 1 to 9 based on an isolation layer preventing photoresist denaturation during the process of etching graphene with oxygen plasma.

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