Low-energy electron irradiation lithography method

Abstract

This invention discloses a low-energy electron irradiation photolithography method, comprising the following steps: providing a substrate with a polymer film covering its surface; placing the substrate with the polymer film covering its surface in the vacuum chamber of an electron cyclotron resonance plasma nanosurface processing system; covering the surface of the polymer film with a mask having a preset pattern; setting an aperture structure in front of the mask for electron irradiation treatment; developing the electron-irradiated substrate in a developing solution to obtain the desired pattern on the substrate; wherein the electron irradiation treatment uses remote plasma, the diameter of the central hole of the aperture structure is in the range of 0-35 mm, and the irradiation current of the electron irradiation treatment is 0.5-5 mA. This invention allows for precise control of the low-energy electron irradiation area and irradiation dose, resulting in a larger interaction area and higher processing efficiency compared to high-energy electron irradiation, thus solving the problem of low production efficiency in existing photolithography methods.

Description

Technical Field

[0001] This invention relates to the field of photolithography, and more particularly to a low-energy electron irradiation photolithography method. Background Technology

[0002] Photolithography is a critical step in semiconductor device manufacturing, used to create desired patterns on a target substrate. The photolithography process includes: substrate preparation, spin-coating of photoresist, pre-baking, exposure, post-baking, development, etching or thin film deposition, and photoresist removal. This process involves multiple steps, each requiring a single, specific piece of equipment, which increases the time and cost of device manufacturing.

[0003] Regarding the exposure process, existing ultraviolet lithography methods can achieve micro-machining, have a large working area, and a fast exposure rate. However, as the resolution of the equipment increases, its complexity and cost also increase. When polymethyl methacrylate (PMMA) is used for negative tone exposure, a crosslinking agent such as Irgacure 651 needs to be added. Existing electron beam lithography methods have the advantage of high resolution and do not require a mask, but their throughput is relatively low, which is not conducive to large-scale manufacturing, and the required equipment cost is high. If a large electron irradiation dose is applied, a large amount of charge accumulation may occur, or even electric spark discharge may occur, which cannot guarantee the accuracy of the pattern.

[0004] ECR (Electron Resonance Catalysis) is an advanced surface treatment technology based on the principle of electron cyclotron resonance, enabling precise control over specific nanostructures and morphologies. Methods for growing three-dimensional graphene films using ECR for physical vapor deposition (PVD) and chemical vapor deposition (CVD) have been reported in the literature. Existing PVD methods involve bombarding a target material with sputtered ions, with the bombarded particles depositing on the target to form a thin film. This deposition process typically uses a relatively high substrate current, ranging from 0.6 to 2 A. Existing CVD methods involve introducing a carbon source gas, generating carbon plasma under argon plasma activation, and depositing the carbon plasma onto a substrate to form a graphene carbon film. This deposition process also typically uses a relatively high substrate current, ranging from 0.2 to 2 A.

[0005] In the aforementioned literature reports, the current conditions are all much greater than the current required for PMMA lithography. Therefore, the existing technology does not meet the requirements for lithography, and it is necessary to develop a lithography method with a small dose and controllable irradiation current. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a low-energy electron irradiation lithography method, which aims to solve the problem that it is difficult to integrate multiple processes into one device and the production efficiency is low in existing lithography methods.

[0007] The technical solution of the present invention is as follows:

[0008] A first aspect of the present invention provides a low-energy electron irradiation lithography method, the low-energy electron irradiation lithography method comprising the following steps:

[0009] Provide a substrate with a polymer film coating on its surface;

[0010] A substrate with a polymer film on its surface is placed in the vacuum chamber of an electron cyclotron resonance plasma nanosurface processing system. A mask with a preset pattern is placed on the surface of the polymer film. An aperture structure is set in front of the mask for electron irradiation treatment.

[0011] The substrate after electron irradiation is developed in a developing solution to obtain the desired pattern on the substrate.

[0012] The electron irradiation treatment uses remote plasma, the diameter of the central hole of the aperture structure is in the range of 0-35mm, and the irradiation current of the electron irradiation treatment is 0.5-5mA.

[0013] Preferably, providing a substrate with a polymer film covering its surface specifically includes the following steps:

[0014] Provide substrate and polymer solution;

[0015] The polymer solution is transferred to the surface of the substrate, and then dried and heated to obtain a substrate with a polymer film covering the surface.

[0016] Preferably, the polymer solution comprises a polymer and a solvent, wherein the polymer is selected from one or more of polymethyl methacrylate, epoxy resin, cyclized polybutadiene, photosensitive resin, poly-α-methylstyrene, polyisobutylene, polymethyl methacrylate, and polyethyl α-cyanoacrylate.

[0017] Preferably, the heating treatment temperature is 180°C and the heating treatment time is 90 seconds.

[0018] Preferably, the steps of placing a substrate with a polymer film on its surface in the vacuum chamber of an electron cyclotron resonance plasma nanosurface processing system, covering the surface of the polymer film with a mask having a preset pattern, and setting an aperture structure in front of the mask for electron irradiation processing specifically include:

[0019] A substrate with a polymer film covering its surface is placed on a substrate holder in the vacuum chamber of an electron cyclotron resonance plasma nanosurface processing system. A mask with a preset pattern is placed on the surface of the polymer film. An aperture structure is set in front of the mask, and the vacuum is evacuated to a preset value.

[0020] Argon gas is introduced, and under the combined action of microwaves and a magnetic field, the argon gas is ionized into argon plasma;

[0021] The substrate is set to a positive bias voltage to attract electrons from the argon plasma to irradiate the polymer film on the substrate surface and the mask with a preset pattern on the polymer film.

[0022] Preferably, in the step of evacuating to a preset value, the preset value is 4×10. -4 Pa.

[0023] Preferably, the substrate bias voltage is 50-200V.

[0024] Preferably, the step of setting the substrate bias voltage to a positive bias voltage also includes setting the substrate current: the substrate current is 0.5-120mA.

[0025] Preferably, the electron irradiation treatment time is 1-30 seconds.

[0026] Preferably, the developing time is 40 seconds, and the developing solution is selected from one or more of methyl isobutyl ketone solution, isopropanol solution, and acetone solution.

[0027] Beneficial effects:

[0028] This invention provides a low-energy electron irradiation lithography method that can precisely control the low-energy electron irradiation area and irradiation dose. It has a larger effective area and higher processing efficiency than high-energy electron beams. It helps to integrate multiple processes such as lithography, etching, ion implantation, and coating into one device, and can solve the problem of low production efficiency in existing lithography methods. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a remote plasma low-energy electron irradiation photolithography experimental setup.

[0030] Figure 2 This is a general diagram of the photolithography aperture structure under low-energy electron irradiation.

[0031] Figure 3 This is a cross-sectional view of a photolithography aperture structure irradiated by low-energy electrons.

[0032] Figure 4 The flowcharts are for the PMMA positive photolithography process in Examples 1-5.

[0033] Figure 5 The image shows a photomicrograph of a circular pattern formed during PMMA lithography in Example 1, with a bias voltage of 100V, a current of 0.5mA, and a time of 1s on a P-type conductive silicon.

[0034] Figure 6The image shows a square pattern of P-type conductive silicon under a bias voltage of 100V, a current of 1.5mA, and a time of 1s during PMMA lithography in Example 2.

[0035] Figure 7 The image shows a rectangular pattern of P-type conductive silicon under a bias voltage of 100V, a current of 1.5mA, and a time of 1s during PMMA lithography in Example 3.

[0036] Figure 8 This is a photomicrograph of a circular pattern of 300nm SiO2 / Si under a bias voltage of 100V, a current of 1.5mA, and a time of 1s during PMMA lithography in Example 4.

[0037] Figure 9 The image shows a square pattern of SiO2 / Si at 300 nm under a bias of 100 V, a current of 1.5 mA, and a time of 1 s during PMMA lithography in Example 5.

[0038] Figure 10 The flowcharts for the PMMA negative lithography process in Examples 6-9 are shown.

[0039] Figure 11 The image shows a photomicrograph of a circular pattern formed during PMMA lithography in Example 6, with a bias voltage of 100V, a current of 30mA, and a time of 30s on a P-type conductive silicon.

[0040] Figure 12 The image shows a square pattern of P-type conductive silicon under a bias voltage of 100V, a current of 30mA, and a time of 30s during PMMA lithography in Example 7.

[0041] Figure 13 The image shows a rectangular pattern of P-type conductive silicon under a bias voltage of 100V, a current of 30mA, and a time of 30s during PMMA lithography in Example 8.

[0042] Figure 14 This is a photomicrograph of a circular pattern of 300nm SiO2 / Si under a bias voltage of 100V, a current of 20mA, and a time of 30s during PMMA lithography in Example 9. Detailed Implementation

[0043] This invention provides a low-energy electron irradiation lithography method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0044] This invention provides a low-energy electron irradiation lithography method, and the schematic diagram of the experimental setup used is shown below. Figure 1 As shown, the low-energy electron irradiation lithography method includes the following steps:

[0045] Provide a substrate with a polymer film coating on its surface;

[0046] A substrate with a polymer film on its surface is placed in the vacuum chamber of an electron cyclotron resonance plasma nanosurface processing system. A mask with a preset pattern is placed on the surface of the polymer film. An aperture structure is set in front of the mask for electron irradiation treatment.

[0047] The substrate after electron irradiation is developed in a developing solution to obtain the desired pattern on the substrate.

[0048] The electron irradiation treatment uses remote plasma, the diameter of the central hole of the aperture structure is in the range of 0-35mm, and the irradiation current of the electron irradiation treatment is 0.5-5mA.

[0049] Plasma contains unionized gas molecules, charged ions, electrons, and free radicals. Remote plasma separates the plasma generation chamber from the plasma processing chamber. To reduce and precisely control the irradiation current, this embodiment employs remote plasma for electron irradiation. A schematic diagram of the experimental setup is shown below. Figure 1 As shown, only the left coil is energized, generating plasma at the left magnetic coil. The target substrate is fixed on the substrate holder, approximately 42 cm away from the left coil, separating the plasma generation area from the electron irradiation area. A positive bias voltage is applied to the substrate holder to attract electrons from the distant plasma. Combined with the adjustment of the aperture structure, better and more uniform electron irradiation is achieved. The plasma density affects the electron content within the plasma; by controlling the plasma density, the irradiation current can be adjusted.

[0050] In this embodiment, the aperture structure restricts the amount of light beam passing through the optical system. By controlling the size of the aperture, the amount of light beam can be limited, thus precisely controlling the range of electron irradiation. The aperture structure is grounded at zero potential and does not attract or repel electrons. This property of allowing central electrons to pass through has two effects in low-energy electron lithography systems: firstly, after electrons separate from the plasma, the irradiation area can be adjusted according to the substrate position; secondly, the aperture can also shield electrons with excessively large incident angles. The aperture structure used in this embodiment is as follows... Figure 2 , 3As shown, this structure prevents electrons from passing through, while electrons in the center can pass through the central aperture of the aperture structure. The main structure of the aperture is a pupil-type structure, and there is an adjustment dial on the protective cover. By rotating the adjustment dial, the size of the central aperture is changed. Considering the size of the substrate area and processing efficiency, the diameter of the central aperture of the aperture structure is set in the range of 0-35mm in photolithography, preferably 15mm.

[0051] This invention generates ECR remote plasma through the combined action of a magnetic field generated by a magnetic coil and microwaves generated by a microwave generator. Electrons from the ECR remote plasma are used as the light source for photolithography. Simultaneously, an aperture structure is placed in front of the substrate (its structural diagram and cross-sectional view are shown below). Figure 2 , Figure 3 The range of electron irradiation is controlled by low-energy electron irradiation. The pattern on the photomask is transferred to the polymer film (photoresist) of the substrate through low-energy electron irradiation to achieve photolithography, thereby realizing low-energy electron irradiation controllable photolithography.

[0052] The low-energy electron irradiation lithography method provided in this invention can precisely control the electron motion state, resulting in high processing efficiency and facilitating the integration of multiple processes such as photolithography, etching, ion implantation, and deposition into a single device. Compared to the high current density commonly used in previous ECR low-energy electron irradiation thin film preparation processes, the low-energy electron irradiation lithography method provided in this invention uses a smaller irradiation current and achieves precise control over this small irradiation current. To meet the irradiation current required for photolithography, an adjustable aperture structure is designed and installed in front of the substrate. The diameter of the center hole of the aperture structure ranges from 0-35 mm. Combined with the use of remote plasma, the irradiation current can be controlled within the range of 0.5-5 mA by adjusting the current of the magnetic coil, the operating voltage, and the microwave current.

[0053] Furthermore, the low-energy electron irradiation lithography method provided in this invention has a larger effective area than the high-energy electron beam method. The specific reasons are as follows: 1. Due to the physical characteristics of low-energy electrons: Low-energy electrons typically refer to electrons with energies in the range of 0.5 keV to 5 keV. They are more prone to inelastic scattering in the resist (photoresist). Inelastic scattering causes electrons to lose energy, limiting their effective range to a smaller area. However, this scattering characteristic is an advantage in low-energy electron lithography because it can limit the energy distribution required for exposure to a smaller area, thereby improving the resolution of the lithography. 2. Due to the interaction between low-energy electrons and the photoresist: When low-energy electrons irradiate the photoresist, they interact with the atoms and molecules in the photoresist, causing chemical changes in the photoresist. Because low-energy electrons lose energy more easily, they can more effectively transfer energy to the photoresist when interacting with it, thereby triggering a chemical reaction. This efficient energy transfer method makes low-energy electrons more effective at acting on the photoresist with the same number of electrons. 3. Limitations of high-energy electron beams: In contrast, high-energy electron beams have strong penetrating power, easily passing through the photoresist to reach the substrate, where they lose most of their energy, generating heat. This strong penetrating power can lead to excessively large exposure areas, reducing the resolution of the lithography. Furthermore, if the electron quantity is large, the substrate may be damaged by excessive heat. Therefore, the application of high-energy electron beams in lithography is somewhat limited. 4. Advantages of low-energy electron irradiation lithography: Because low-energy electrons are more prone to inelastic scattering in the photoresist and can transfer energy to the photoresist more efficiently, low-energy electron irradiation lithography has an advantage in terms of the effective area. Specifically, low-energy electrons can achieve high-precision exposure in a smaller area, resulting in smaller feature sizes and higher resolution. This advantage makes low-energy electron irradiation lithography have enormous potential in the fabrication of nanoelectronics, nano-optical devices, and other nanotechnology applications.

[0054] In some embodiments, providing a substrate with a surface covered by a polymer film specifically includes the following steps:

[0055] Provide substrate and polymer solution;

[0056] The polymer solution is transferred to the surface of the substrate, and then dried and heated to obtain a substrate with a polymer film covering the surface.

[0057] In this embodiment of the invention, the substrate can be a silicon substrate, a silicon dioxide substrate, etc., but is not limited thereto.

[0058] In some embodiments, the polymer solution comprises a polymer and a solvent, wherein the polymer is selected from one or more of polymethyl methacrylate, epoxy resin, cyclized polybutadiene, photosensitive resin, poly-α-methylstyrene, polyisobutylene, polymethyl methacrylate, and polyethyl α-cyanoacrylate.

[0059] In some embodiments, the heat treatment temperature is 180°C and the heat treatment time is 90 seconds.

[0060] The heating treatment in this embodiment is a pre-baking process, also known as soft baking, which is an important step in the photolithography process. Its main purpose is to evaporate the solvent in the photoresist through heating, thereby enhancing the adhesion between the photoresist and the substrate, eliminating internal stress generated during homogenization, and reducing dust contamination. The high temperature of 180°C can rapidly remove residual moisture and solvent from the polymer in a short time (90 seconds), avoiding bubbles and cracks, thus improving the accuracy and quality of the photolithographic pattern. Simultaneously, it optimizes the photoresist performance, ensuring that the photolithographic pattern does not peel off or deform during development and etching, and forming a more uniform coating on the silicon wafer, thereby improving the uniformity and consistency of the photolithographic pattern. Moreover, the relatively short 90-second pre-baking time can shorten the overall photolithography process time, improve production efficiency, and reduce overall energy consumption, thus helping to lower production costs. Furthermore, stable pre-baking conditions can ensure consistent photoresist performance between different batches, reducing the impact of batch differences on the final product. By precisely controlling the pre-baking temperature and time, the drying degree and performance of the photoresist can be more accurately controlled, improving the controllability and stability of the process.

[0061] In some embodiments, the steps of placing a substrate with a polymer film coating on its surface in the vacuum chamber of an electron cyclotron resonance plasma nanosurface processing system, covering the surface of the polymer film with a mask having a preset pattern, and setting an aperture structure in front of the mask for electron irradiation processing specifically include:

[0062] A substrate with a polymer film covering its surface is placed on a substrate holder in the vacuum chamber of an electron cyclotron resonance plasma nanosurface processing system. A mask with a preset pattern is placed on the surface of the polymer film. An aperture structure is set in front of the mask, and the vacuum is evacuated to a preset value.

[0063] Argon gas is introduced, and under the combined action of microwaves and a magnetic field, the argon gas is ionized into argon plasma;

[0064] The substrate is set to a positive bias voltage to attract electrons from the argon plasma to irradiate the polymer film on the substrate surface and the mask with a preset pattern on the polymer film.

[0065] In some embodiments, in the step of evacuating to a preset value, the preset value is 4 × 10⁻⁶. -4 Pa.

[0066] Setting the vacuum preset value within this range can avoid the influence of impurity gases and ensure high purity during the photolithography process; therefore, the cavity must achieve a high degree of vacuum.

[0067] In some embodiments, the substrate bias voltage is 50-200V.

[0068] The substrate bias voltage affects the interaction depth between electrons and photoresist. To increase the interaction depth, the irradiation voltage can be increased. Under the above substrate bias voltage range, the area blocked by the mask has no pinholes or other defects, the pattern size is accurate and uniform, the steps of each pattern are neat, and the shape of the pattern after photolithography is slightly inverted trapezoidal, with no residual material in the center.

[0069] In some embodiments, setting the substrate bias voltage to a positive bias voltage also includes setting the substrate current: the substrate current is 0.5-120mA.

[0070] Different substrate currents affect the amount of electrons applied to the photoresist, but the irradiation time has a more significant effect on the photoresist and results in more residue. Therefore, setting the above-mentioned substrate current range to reduce the substrate current and make it highly controllable helps to control the irradiation time, which can meet the charge requirements of PMMA lithography and achieve low-energy electron irradiation lithography.

[0071] In some embodiments, the electron irradiation treatment lasts for 1-30 seconds.

[0072] In some embodiments, the developing process takes 40 seconds, and the developing solution is selected from one or more of methyl isobutyl ketone solution, isopropanol solution, and acetone solution.

[0073] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are merely some embodiments of the present invention, not all embodiments, and are intended only to illustrate the present invention and not to limit it. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0074] Example 1

[0075] With a resistivity less than 0.0015Ω .P-type cm <100> Oriented monocrystalline silicon was selected as the substrate and cut into 25mm × 25mm pieces using a diamond pen. It was first sonicated in acetone solution for 7 minutes, then transferred to ethanol solution and sonicated for 7 minutes, and finally sonicated in deionized water for 7 minutes. After cleaning, it was dried with a nitrogen gun. Figure 4 As shown, 495KPMMA A2 type photoresist was uniformly spin-coated onto the silicon substrate using a KW-4A spin coater: the spin coater parameters were set as follows: spin speed 4000rpm, initial spin speed 1000rpm, and spin time 45s.

[0076] The silicon substrate with the above-mentioned uniform adhesive was heated at 180°C for 90 seconds. This process was carried out in a clean room.

[0077] After placing the silicon substrate and the photomask made by deep silicon etching onto the substrate holder, a mechanical pump is used to pre-evacuate the pre-vacuum chamber until the chamber pressure reaches 10. -2 At Pa, the substrate holder is moved to the magnetic mirror position. The molecular pump continues to operate until the cavity pressure reaches the background vacuum of 4 × 10⁻⁶. -4 At Pa, argon gas is introduced into the cavity, and the gas flow rate is adjusted to 12 sccm. The microwave power is adjusted to 70W, and the left magnetic coil is 35.5A. At this time, remote argon plasma is generated in the cavity. Then, the substrate bias voltage is set to +100V, the substrate current is 0.5mA, the substrate holder baffle is opened, and a time relay is connected in the circuit. Before photolithography, the photolithography time is set to 1s for the relay. After the time relay is turned on, the circuit is turned on, and the relay is turned off after 1s.

[0078] The photolithographically etched substrate is placed in a developing solution for development. The developing solution used for PMMA as a positive photoresist is a mixture of methyl isobutyl ketone (MIBK) and isopropanol (IPA) solutions in a 1:3 ratio. The development time is 40 seconds. After development, the substrate is rinsed and soaked in deionized water for 1 minute to obtain the desired circular pattern. See [link to relevant documentation]. Figure 5 .

[0079] Example 2

[0080] With a resistivity less than 0.0015Ω . P-type cm <100> Oriented monocrystalline silicon was selected as the substrate and cut into 25mm × 25mm pieces using a diamond pen. It was first sonicated in acetone solution for 7 minutes, then transferred to ethanol solution and sonicated for 7 minutes, and finally sonicated in deionized water for 7 minutes. After cleaning, it was dried with a nitrogen gun. Figure 4As shown, 495KPMMA A2 type photoresist was uniformly spin-coated onto the silicon substrate using a KW-4A spin coater: the spin coater parameters were set as follows: spin speed 4000rpm, initial spin speed 1000rpm, and spin time 45s.

[0081] The silicon substrate with the above-mentioned uniform adhesive was heated at 180°C for 90 seconds. This process was carried out in a clean room.

[0082] After placing the silicon substrate and the photomask made by deep silicon etching onto the substrate holder, a mechanical pump is used to pre-evacuate the pre-vacuum chamber until the chamber pressure reaches 10. -2 At Pa, the substrate holder is moved to the magnetic mirror position. The molecular pump continues to operate until the cavity pressure reaches the background vacuum of 4 × 10⁻⁶. -4 At Pa, argon gas is introduced into the cavity, and the gas flow rate is adjusted to 12 sccm. The microwave power is adjusted to 100W, and the left magnetic coil is 35.5A. At this time, remote argon plasma is generated in the cavity. Then, the substrate bias voltage is set to +100V, the substrate current is 1.5mA, the substrate holder baffle is opened, and a time relay is connected in the circuit. Before photolithography, the photolithography time is set to 1s for the relay. After the time relay is turned on, the circuit is turned on, and the relay is turned off after 1s.

[0083] The photolithographically etched substrate is placed in a developing solution for development. The developing solution used for PMMA as a positive photoresist is a mixture of methyl isobutyl ketone (MIBK) and isopropanol (IPA) solutions in a 1:3 ratio. The development time is 40 seconds. After development, the substrate is rinsed and soaked in deionized water for 1 minute to obtain the desired square pattern. (See...) Figure 6 .

[0084] Example 3

[0085] With a resistivity less than 0.0015Ω . P-type cm <100> Oriented monocrystalline silicon was selected as the substrate and cut into 25mm × 25mm pieces using a diamond pen. It was first sonicated in acetone solution for 7 minutes, then transferred to ethanol solution and sonicated for 7 minutes, and finally sonicated in deionized water for 7 minutes. After cleaning, it was dried with a nitrogen gun. Figure 4 As shown, 495KPMMA A2 type photoresist was uniformly spin-coated onto the silicon substrate using a KW-4A spin coater: the spin coater parameters were set as follows: spin speed 4000rpm, initial spin speed 1000rpm, and spin time 45s.

[0086] The silicon substrate with the above-mentioned uniform adhesive was heated at 180°C for 90 seconds. This process was carried out in a clean room.

[0087] After placing the silicon substrate and the photomask made by deep silicon etching onto the substrate holder, a mechanical pump is used to pre-evacuate the pre-vacuum chamber until the chamber pressure reaches 10. -2 At Pa, the substrate holder is moved to the magnetic mirror position. The molecular pump continues to operate until the cavity pressure reaches the background vacuum of 4 × 10⁻⁶. -4 At Pa, argon gas is introduced into the cavity, and the gas flow rate is adjusted to 12 sccm. The microwave power is adjusted to 100W, and the left magnetic coil is 35.5A. At this time, remote argon plasma is generated in the cavity. Then, the substrate bias voltage is set to +100V, the substrate current is 1.5mA, the substrate holder baffle is opened, and a time relay is connected in the circuit. Before photolithography, the photolithography time is set to 1s for the relay. After the time relay is turned on, the circuit is turned on, and the relay is turned off after 1s.

[0088] The photolithographically etched substrate is placed in a developing solution for development. The developing solution used for PMMA as a positive photoresist is a mixture of methyl isobutyl ketone (MIBK) and isopropanol (IPA) solutions in a 1:3 ratio. The development time is 40 seconds. After development, the substrate is rinsed and soaked in deionized water for 1 minute to obtain the desired rectangular pattern. (See...) Figure 7 .

[0089] Example 4

[0090] Silica was selected as the substrate and cut into 25mm × 25mm pieces using a diamond pen. It was first sonicated in acetone solution for 7 minutes, then transferred to ethanol solution and sonicated for 7 minutes, and finally sonicated in deionized water for 7 minutes. After cleaning, it was dried with a nitrogen gun. Figure 4 As shown, 495K PMMA A2 photoresist was uniformly spin-coated onto the silicon dioxide substrate using a KW-4A spin coater: the spin coater parameters were set as follows: spin speed 4000 rpm, initial spin speed 1000 rpm, and spin time 45 s.

[0091] The silica substrate with the above-mentioned uniformly coated adhesive was heated at 180°C for 90 seconds. This process was carried out in a clean room.

[0092] After placing the silicon dioxide substrate and the photomask made by deep silicon etching onto the substrate holder, a mechanical pump is used to pre-evacuate the pre-vacuum chamber until the chamber pressure reaches 10. -2 At Pa, the substrate holder is moved to the magnetic mirror position. The molecular pump continues to operate until the cavity pressure reaches the background vacuum of 4 × 10⁻⁶. -4At Pa, argon gas is introduced into the cavity, and the gas flow rate is adjusted to 12 sccm. The microwave power is adjusted to 100W, and the left magnetic coil is 35.5A. At this time, remote argon plasma is generated in the cavity. Then, the substrate bias voltage is set to +100V, the substrate current is 1.5mA, the substrate holder baffle is opened, and a time relay is connected in the circuit. Before photolithography, the photolithography time is set to 1s for the relay. After the time relay is turned on, the circuit is turned on, and the relay is turned off after 1s.

[0093] The photolithographically etched substrate was placed in a developing solution for development. The developing solution used for PMMA as a positive photoresist was a mixture of methyl isobutyl ketone (MIBK) and isopropanol (IPA) solutions in a 1:3 ratio. The development time was 40 seconds. After development, the substrate was rinsed and soaked in deionized water for 1 minute to obtain a circular pattern with the desired diameter of 150 μm. (See...) Figure 8 .

[0094] Example 5

[0095] Silica was selected as the substrate and cut into 25mm × 25mm pieces using a diamond pen. It was first sonicated in acetone solution for 7 minutes, then transferred to ethanol solution and sonicated for 7 minutes, and finally sonicated in deionized water for 7 minutes. After cleaning, it was dried with a nitrogen gun. Figure 4 As shown, 495K PMMA A2 photoresist was uniformly spin-coated onto the silicon dioxide substrate using a KW-4A spin coater: the spin coater parameters were set as follows: spin speed 4000 rpm, initial spin speed 1000 rpm, and spin time 45 s.

[0096] The silica substrate with the above-mentioned uniformly coated adhesive was heated at 180°C for 90 seconds. This process was carried out in a clean room.

[0097] After placing the silicon dioxide substrate and the photomask made by deep silicon etching onto the substrate holder, a mechanical pump is used to pre-evacuate the pre-vacuum chamber until the chamber pressure reaches 10. -2 At Pa, the substrate holder is moved to the magnetic mirror position. The molecular pump continues to operate until the cavity pressure reaches the background vacuum of 4 × 10⁻⁶. -4 At Pa, argon gas is introduced into the cavity, and the gas flow rate is adjusted to 12 sccm. The microwave power is adjusted to 100W, and the left magnetic coil is 35.5A. At this time, remote argon plasma is generated in the cavity. Then, the substrate bias voltage is set to +100V, the substrate current is 1.5mA, the substrate holder baffle is opened, and a time relay is connected in the circuit. Before photolithography, the photolithography time is set to 1s for the relay. After the time relay is turned on, the circuit is turned on, and the relay is turned off after 1s.

[0098] The photolithographically etched substrate was placed in a developing solution for development. The developing solution used for PMMA as a positive photoresist was a mixture of methyl isobutyl ketone (MIBK) and isopropanol (IPA) solutions in a 1:3 ratio. The development time was 40 seconds. After development, the substrate was rinsed and soaked in deionized water for 1 minute to obtain a square pattern with the desired side length of 50 μm. (See...) Figure 9 .

[0099] Example 6

[0100] With a resistivity less than 0.0015Ω . P-type cm <100> Oriented monocrystalline silicon was selected as the substrate and cut into 25mm × 25mm pieces using a diamond pen. It was first sonicated in acetone solution for 7 minutes, then transferred to ethanol solution and sonicated for 7 minutes, and finally sonicated in deionized water for 7 minutes. After cleaning, it was dried with a nitrogen gun. Figure 10 As shown, 495KPMMA A2 type photoresist was uniformly spin-coated onto the silicon substrate using a KW-4A spin coater: the spin coater parameters were set as follows: spin speed 4000rpm, initial spin speed 1000rpm, and spin time 45s.

[0101] The substrate with the above-mentioned uniformly coated adhesive was heated at 180°C for 90 seconds. This process was carried out in a clean room for photoluminescence.

[0102] After placing the silicon substrate and the photomask made by deep silicon etching onto the substrate holder, a mechanical pump is used to pre-evacuate the pre-vacuum chamber until the chamber pressure reaches 10. -2 At Pa, the substrate holder is moved to the magnetic mirror position. The molecular pump continues to operate until the cavity pressure reaches the background vacuum of 4 × 10⁻⁶. -4 At Pa, argon gas is introduced into the cavity, and the gas flow rate is adjusted to 12 sccm. The microwave power is adjusted to 100W, and the left, middle, and right magnetic coils are 38A, 22A, and 23A respectively. At this time, remote argon plasma is generated in the cavity. Then, the substrate bias voltage is set to +100V, the substrate current is set to 30mA, the substrate holder baffle is opened, and a time relay is connected in the circuit. Before photolithography, the photolithography time is set to 30s for the relay. After the time relay is turned on, the circuit is turned on, and the relay is turned off after 30s.

[0103] The photolithographically etched substrate is then placed in a developing solution (acetone solution) for development. The PMMA transforms into a negative photoresist at this point. The development time is 40 seconds. After development, the substrate is rinsed and soaked in deionized water for 1 minute. The electron-irradiated areas are retained, while the areas blocked by the mask are washed away with acetone, thus obtaining the desired circular pattern. (See...) Figure 11 .

[0104] Example 7

[0105] With a resistivity less than 0.0015Ω . P-type cm <100> Oriented monocrystalline silicon was selected as the substrate and cut into 25mm × 25mm pieces using a diamond pen. It was first sonicated in acetone solution for 7 minutes, then transferred to ethanol solution and sonicated for 7 minutes, and finally sonicated in deionized water for 7 minutes. After cleaning, it was dried with a nitrogen gun. Figure 10 As shown, 495KPMMA A2 type photoresist was uniformly spin-coated onto the silicon substrate using a KW-4A spin coater: the spin coater parameters were set as follows: spin speed 4000rpm, initial spin speed 1000rpm, and spin time 45s.

[0106] The substrate with the above-mentioned uniformly coated adhesive was heated at 180°C for 90 seconds. This process was carried out in a clean room for photoluminescence.

[0107] After placing the silicon substrate and the photomask made by deep silicon etching onto the substrate holder, a mechanical pump is used to pre-evacuate the pre-vacuum chamber until the chamber pressure reaches 10. -2 At Pa, the substrate holder is moved to the magnetic mirror position. The molecular pump continues to operate until the cavity pressure reaches the background vacuum of 4 × 10⁻⁶. -4 At Pa, argon gas is introduced into the cavity, and the gas flow rate is adjusted to 12 sccm. The microwave power is adjusted to 100W, and the left, middle, and right magnetic coils are 38A, 22A, and 17A respectively. At this time, remote argon plasma is generated in the cavity. Then, the substrate bias voltage is set to +100V, the substrate current is set to 30mA, the substrate holder baffle is opened, and a time relay is connected in the circuit. Before photolithography, the photolithography time is set to 30s for the relay. After the time relay is turned on, the circuit is turned on, and the relay is turned off after 30s.

[0108] The photolithographically etched substrate is then placed in a developer solution for development. PMMA transforms into a negative photoresist at this point. The developer solution used is acetone. The development time is 40 seconds. After development, the substrate is rinsed and soaked in deionized water for 1 minute. The electron-irradiated areas are retained, while the areas blocked by the mask are washed away with acetone, thus obtaining the desired square pattern. See [link to documentation]. Figure 12 .

[0109] Example 8

[0110] With a resistivity less than 0.0015Ω . P-type cm <100> Oriented monocrystalline silicon was selected as the substrate and cut into 25mm × 25mm pieces using a diamond pen. It was first sonicated in acetone solution for 7 minutes, then transferred to ethanol solution and sonicated for 7 minutes, and finally sonicated in deionized water for 7 minutes. After cleaning, it was dried with a nitrogen gun. Figure 10As shown, 495KPMMA A2 type photoresist was uniformly spin-coated onto the silicon substrate using a KW-4A spin coater: the spin coater parameters were set as follows: spin speed 4000rpm, initial spin speed 1000rpm, and spin time 45s.

[0111] The substrate with the above-mentioned uniformly coated adhesive was heated at 180°C for 90 seconds. This process was carried out in a clean room for photoluminescence.

[0112] After placing the silicon substrate and the photomask made by deep silicon etching onto the substrate holder, a mechanical pump is used to pre-evacuate the pre-vacuum chamber until the chamber pressure reaches 10. -2 At Pa, the substrate holder is moved to the magnetic mirror position. The molecular pump continues to operate until the cavity pressure reaches the background vacuum of 4 × 10⁻⁶. -4 At Pa, argon gas is introduced into the cavity, and the gas flow rate is adjusted to 12 sccm. The microwave power is adjusted to 100W, and the left, middle, and right magnetic coils are 38A, 22A, and 17A respectively. At this time, remote argon plasma is generated in the cavity. Then, the substrate bias voltage is set to +100V, the substrate current is set to 30mA, the substrate holder baffle is opened, and a time relay is connected in the circuit. Before photolithography, the photolithography time is set to 30s for the relay. After the time relay is turned on, the circuit is turned on, and the relay is turned off after 30s.

[0113] The photolithographically etched substrate is then placed in a developing solution (acetone solution) for development. The PMMA transforms into a negative photoresist at this point. The development time is 40 seconds. After development, the substrate is rinsed and soaked in deionized water for 1 minute. The electron-irradiated areas are retained, while the areas blocked by the mask are washed away with acetone, thus obtaining the desired rectangular pattern. (See...) Figure 13 .

[0114] Example 9

[0115] Silica was selected as the substrate and cut into 25mm × 25mm pieces using a diamond pen. It was first sonicated in acetone solution for 7 minutes, then transferred to ethanol solution and sonicated for 7 minutes, and finally sonicated in deionized water for 7 minutes. After cleaning, it was dried with a nitrogen gun. Figure 10 As shown, 495K PMMA A2 photoresist was uniformly spin-coated onto the silicon dioxide substrate using a KW-4A spin coater: the spin coater parameters were set as follows: spin speed 4000 rpm, initial spin speed 1000 rpm, and spin time 45 s.

[0116] The silica substrate with the above-mentioned uniformly coated adhesive was heated at 180°C for 90 seconds. This process was carried out in a clean room.

[0117] After placing the silicon dioxide substrate and the photomask made by deep silicon etching onto the substrate holder, a mechanical pump is used to pre-evacuate the pre-vacuum chamber until the chamber pressure reaches 10. -2 At Pa, the substrate holder is moved to the magnetic mirror position. The molecular pump continues to operate until the cavity pressure reaches the background vacuum of 4 × 10⁻⁶. -4 At Pa, argon gas is introduced into the cavity, and the gas flow rate is adjusted to 12 sccm. The microwave power is adjusted to 100W, and the left, middle, and right magnetic coils are 38A, 22A, and 16A respectively. At this time, remote argon plasma is generated in the cavity. Then, the substrate bias voltage is set to +100V, the substrate current is set to 20mA, the substrate holder baffle is opened, and a time relay is connected in the circuit. Before photolithography, the photolithography time is set to 30s for the relay. After the time relay is turned on, the circuit is turned on, and the relay is turned off after 30s.

[0118] The photolithographically etched substrate is then placed in a developing solution (acetone solution) for development. The PMMA transforms into a negative photoresist at this point. The development time is 40 seconds. After development, the substrate is rinsed and soaked in deionized water for 1 minute. The electron-irradiated areas are retained, while the areas blocked by the mask are washed away with acetone, thus obtaining the desired circular pattern. (See...) Figure 14 .

[0119] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A low-energy electron irradiation photolithography method, characterized in that, The low-energy electron irradiation lithography method includes the following steps: Provide a substrate with a polymer film coated on its surface; A substrate with a polymer film on its surface is placed in the vacuum chamber of an electron cyclotron resonance plasma nanosurface processing system. A mask with a preset pattern is placed on the surface of the polymer film, and an aperture structure is set in front of the mask for electron irradiation treatment. The substrate after electron irradiation is developed in a developing solution to obtain the desired pattern on the substrate. The electron irradiation treatment uses remote plasma, the diameter of the central hole of the aperture structure is in the range of 0-35 mm, and the irradiation current of the electron irradiation treatment is 0.5-5 mA. The steps of placing a substrate covered with a polymer film in the vacuum chamber of an electron cyclotron resonance plasma nanosurface processing system, covering the surface of the polymer film with a mask having a predetermined pattern, and placing an aperture structure in front of the mask for electron irradiation processing specifically include: A substrate with a polymer film on its surface is placed on a substrate holder in the vacuum chamber of an electron cyclotron resonance plasma nanosurface processing system. A mask with a preset pattern is placed on the surface of the polymer film. An aperture structure is set in front of the mask, and the vacuum is evacuated to a preset value. Argon gas is introduced, and under the combined action of microwaves and a magnetic field, the argon gas is ionized into argon plasma; The substrate is set to a positive bias voltage to attract electrons from the argon plasma to irradiate the polymer film on the substrate surface and the mask with a preset pattern on the polymer film.

2. The low-energy electron irradiation lithography method according to claim 1, characterized in that, Providing a substrate with a polymer film covering its surface specifically includes the following steps: Provide substrate and polymer solution; The polymer solution is transferred to the surface of the substrate, and then dried and heated to obtain a substrate with a polymer film covering the surface.

3. The low-energy electron irradiation lithography method according to claim 2, characterized in that, The polymer solution comprises a polymer and a solvent, wherein the polymer is selected from one or more of polymethyl methacrylate, epoxy resin, cyclized polybutadiene, photosensitive resin, poly-α-methylstyrene, polyisobutylene, polymethyl methacrylate, and poly-α-cyanoacrylate.

4. The low-energy electron irradiation lithography method according to claim 2, characterized in that, The heat treatment temperature is 180℃, and the heat treatment time is 90 s.

5. The low-energy electron irradiation lithography method according to claim 1, characterized in that, In the step of evacuating to a preset value, the preset value is 4×10. -4 Pa.

6. The low-energy electron irradiation lithography method according to claim 1, characterized in that, The substrate bias voltage is 50-200V.

7. The low-energy electron irradiation lithography method according to claim 1, characterized in that, The step of setting the substrate bias voltage to a positive bias voltage also includes setting the substrate current: the substrate current is 0.5-120 mA.

8. The low-energy electron irradiation lithography method according to claim 1, characterized in that, The electron irradiation treatment time is 1-30 s.

9. The low-energy electron irradiation lithography method according to claim 1, characterized in that, The developing process takes 40 seconds, and the developing solution is selected from one or more of methyl isobutyl ketone solution, isopropanol solution, and acetone solution.

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