Low-energy electron irradiation photoetching method

Abstract

The invention discloses a low-energy electron irradiation photoetching method. The method comprises the following steps: providing a substrate of which the surface is covered with a polymer film; the substrate with the surface covered with the polymer film is placed in a vacuum chamber of an electron cyclotron resonance plasma nanometer surface processing system, the surface of the polymer film is covered with a mask plate with a preset pattern, a diaphragm structure is arranged in front of the mask plate, and electron irradiation treatment is carried out; carrying out developing treatment on the substrate subjected to electron irradiation treatment in a developing solution, and obtaining a required pattern on the substrate; wherein remote plasma is adopted in the electron irradiation treatment, the diameter range of a center hole of the diaphragm structure is 0-35 mm, and the irradiation current of the electron irradiation treatment is 0.5-5 mA. According to the method, the irradiation area and the irradiation dose of the low-energy electrons can be accurately regulated and controlled, the action area is larger than that of the high-energy electrons, the processing efficiency is high, and the problem that the production efficiency is low in an existing photoetching method can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of photolithography, and in particular to a low-energy electron irradiation photolithography method. Background Art

[0002] The photolithography process is a key step in the manufacture of semiconductor devices, which is used to form the desired pattern on the target substrate. The steps of the photolithography process include: substrate preparation, spin coating of photoresist, pre-bake, exposure, post-bake, development, etching or thin film deposition, and removal of photoresist. The process includes multiple steps, each of which requires a single specific equipment, which increases the time and cost of device manufacturing.

[0003] As far as the exposure process is concerned, the existing UV lithography method can achieve micro-fabrication, with a large active area and a fast exposure rate, but as the resolution of the equipment increases, its complexity and price also increase; when polymethyl methacrylate (PMMA) is used for negative tone exposure, a cross-linking agent such as Irgacure 651 needs to be added to achieve it. The existing electron beam lithography method has the advantages of high resolution and does not require a mask plate, but its throughput is small, which is not conducive to large-scale production and manufacturing, and the equipment cost required is high; if a large electron irradiation dose is used for exposure, a large amount of charge will accumulate, and even spark discharge will occur, which makes it impossible to guarantee the accuracy of the pattern.

[0004] ECR low-energy electron irradiation technology is an advanced surface treatment technology based on the principle of electron cyclotron resonance, which can achieve precise control of specific nanostructures and morphologies. The method of using ECR low-energy electron irradiation for physical vapor deposition (PVD) and chemical vapor deposition (CVD) to grow three-dimensional graphene films has been reported in the literature. The existing PVD method is to bombard the target material with sputtering ions, and the bombarded particles are deposited on the target material to form a thin film. The substrate current used in the coating process is usually relatively large, which is 0.6-2A. The existing CVD method is to generate carbon plasma on the substrate by introducing a carbon source gas under the activation of argon plasma, and deposit the carbon plasma on the substrate to generate a graphene carbon film. The substrate current used in the coating process is usually relatively large, which is 0.2-2A.

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

[0006] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a low-energy electron irradiation lithography method, aiming to solve the problem in the existing lithography method that it is difficult to integrate multiple processes on one device and the production efficiency is low.

[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] Providing a substrate having a surface covered with a polymer film;

[0010] Placing a substrate with a polymer film on its surface in a vacuum chamber of an electron cyclotron resonance plasma nano-surface processing system, covering the surface of the polymer film with a mask having a preset pattern, arranging an aperture structure in front of the mask, and performing electron irradiation treatment;

[0011] Performing a developing process on the substrate after the electron irradiation process in a developer to obtain a desired pattern on the substrate;

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

[0013] Preferably, the step of providing a substrate having a surface covered with a polymer film specifically comprises the following steps:

[0014] providing a substrate and a polymer solution;

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

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

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

[0018] Preferably, a substrate covered with a polymer film is placed in a vacuum chamber of an electron cyclotron resonance plasma nano-surface processing system, a mask having a preset pattern is covered on the surface of the polymer film, an aperture structure is arranged in front of the mask, and the steps of performing electron irradiation treatment specifically include:

[0019] Placing a substrate with a polymer film on its surface on a substrate rack in a vacuum chamber of an electron cyclotron resonance plasma nano-surface processing system, covering the surface of the polymer film with a mask having a preset pattern, providing an aperture structure in front of the mask, and evacuating the film to a preset value;

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

[0021] The substrate bias voltage is set to a positive bias voltage to attract electrons in the argon plasma to perform electron irradiation on the polymer film on the surface of the substrate 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 the step of setting the substrate current: the substrate current is 0.5-120 mA.

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

[0026] Preferably, the development treatment time is 40 seconds, and the developer is selected from one or more of methyl isobutyl (methyl) ketone solution, isopropyl alcohol solution, and acetone solution.

[0027] Beneficial effects:

[0028] The present invention provides a low-energy electron irradiation lithography method, which can accurately control the low-energy electron irradiation area and irradiation dose. Compared with a high-energy electron beam, the effective area is larger and the processing efficiency is high. It helps to integrate multiple processes such as lithography, etching, ion implantation, and coating on one device, and can solve the problem of low production efficiency in existing lithography methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the remote plasma low-energy electron irradiation lithography experimental device.

[0030] Figure 2 This is the overall diagram of the low-energy electron irradiation lithography aperture structure.

[0031] Figure 3 This is a cross-sectional view of the low-energy electron irradiation lithography aperture structure.

[0032] Figure 4 This is a flow chart of the PMMA positive photolithography process in Examples 1-5.

[0033] Figure 5 This is a light microscope photograph of a circular pattern during PMMA photolithography in Example 1: P-type conductive silicon under a bias of 100 V, a current of 0.5 mA, and a time of 1 s.

[0034] Figure 6This is a light microscope photograph of a square pattern during PMMA lithography in Example 2: P-type conductive silicon under a bias of 100 V, a current of 1.5 mA, and a time of 1 s.

[0035] Figure 7 This is a light microscope photograph of a rectangular pattern during PMMA photolithography in Example 3: P-type conductive silicon under a bias of 100 V, a current of 1.5 mA, and a time of 1 s.

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

[0037] Fig. 9 This is a light microscope photograph of a square pattern of 300nm SiO2 / Si under 100V bias, 1.5mA current and 1s time during PMMA lithography in Example 5.

[0038] Fig.10 This is a flow chart of the PMMA negative photolithography process in Examples 6-9.

[0039] Fig.11 This is a light microscope photograph of a circular pattern during PMMA photolithography in Example 6: P-type conductive silicon under a bias of 100 V, a current of 30 mA, and a time of 30 s.

[0040] Fig.12 This is a light microscope photograph of a square pattern during PMMA photolithography in Example 7: P-type conductive silicon under a bias of 100 V, a current of 30 mA, and a time of 30 s.

[0041] Fig.13 This is a light microscope photograph of a rectangular pattern during PMMA photolithography in Example 8: P-type conductive silicon under a bias of 100 V, a current of 30 mA, and a time of 30 s.

[0042] Fig.14 This is a light microscope photograph of a circular pattern during PMMA lithography in Example 9: 300nm SiO2 / Si under a bias of 100V, a current of 20mA, and a time of 30s. DETAILED DESCRIPTION

[0043] The present invention provides a low-energy electron irradiation lithography method. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] The embodiment of the present invention provides a low-energy electron irradiation lithography method, and the schematic diagram of the experimental device used is as follows: Figure 1 As shown, the low-energy electron irradiation lithography method comprises the following steps:

[0045] Providing a substrate having a surface covered with a polymer film;

[0046] Placing a substrate with a polymer film on its surface in a vacuum chamber of an electron cyclotron resonance plasma nano-surface processing system, covering the surface of the polymer film with a mask having a preset pattern, arranging an aperture structure in front of the mask, and performing electron irradiation treatment;

[0047] Performing a developing process on the substrate after the electron irradiation process in a developer to obtain a desired pattern on the substrate;

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

[0049] Plasma contains unionized gas molecules, charged ions, electrons and free radicals. Remote plasma is to separate the plasma generation chamber from the plasma processing area. In order to reduce and accurately control the irradiation current, this embodiment uses remote plasma during electron irradiation. The schematic diagram of the experimental device is shown in the figure. Figure 1 As shown, only the left coil is energized, plasma is generated at the left magnetic coil, the target substrate is fixed on the substrate rack, and the substrate position is about 42 cm away from the left coil, separating the plasma generation area from the electron irradiation area. By applying a positive bias voltage to the substrate rack to attract electrons in the remote plasma, combined with the regulation of the aperture structure, better and more uniform electron irradiation is formed. The density of the plasma affects the content of electrons in the plasma, and the irradiation current can be adjusted by regulating the plasma density.

[0050] The aperture structure in this embodiment limits the light beam in the optical system. The size of the aperture in the aperture structure is used to limit the amount of light beam passing through, thereby accurately 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 can have two effects in a low-energy electron lithography system. First, after the electrons are separated from the plasma, the electron irradiation site can be regulated according to the position of the substrate. Second, 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, the structure can prevent electrons from passing through, while the central electrons can pass through the central hole 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. The size of the central aperture is changed by turning the adjustment dial. Considering the size of the substrate area and the processing efficiency, the central hole diameter of the aperture structure is set in the range of 0-35mm in lithography, preferably 15mm.

[0051] In the embodiment of the present invention, the magnetic field generated by the magnetic coil and the microwave generated by the microwave generator jointly generate the ECR remote plasma, and the electrons in the ECR remote plasma are used as the light source for photolithography. At the same time, an aperture structure is placed in front of the substrate (its structure diagram and structure cross-sectional diagram are shown in FIG. Figure 2 , Figure 3 ) is used to regulate the range of electron irradiation, and the pattern on the mask is transferred to the polymer film (photoresist) of the substrate through low-energy electron irradiation to achieve photolithography, thereby realizing controllable photolithography by low-energy electron irradiation.

[0052] The low-energy electron irradiation lithography method provided by the embodiment of the present invention can accurately control the motion state of electrons, has high processing efficiency, and helps to integrate multiple processes such as lithography, etching, ion implantation, and coating into one device. Compared with the high current density commonly used in the previous ECR low-energy electron irradiation thin film preparation process, the low-energy electron irradiation lithography method provided by the embodiment of the present invention has a small irradiation current and realizes precise control of the small irradiation current. In order to meet the irradiation current required for lithography, the embodiment of the present invention designs and installs an aperture structure with an adjustable center diameter in front of the substrate. The center hole diameter of the aperture structure ranges from 0-35mm. Combined with the use of remote plasma, the irradiation current is regulated in the range of 0.5-5mA by adjusting the current, working voltage and microwave current of the magnetic coil.

[0053] Moreover, the low-energy electron irradiation lithography method provided by the embodiment of the present invention has a larger action area than the high-energy electron beam, and the specific reasons are as follows: 1. Because of the physical properties of low-energy electrons: low-energy electrons generally refer to electrons with energy in the range of 0.5keV to 5keV, which are more likely to be inelastically scattered in the resist (photoresist). Inelastic scattering causes electrons to lose energy and limits the action range of electrons 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 range, thereby improving the resolution of lithography. 2. Because of the interaction between low-energy electrons and photoresist: when low-energy electrons are irradiated onto the photoresist, they interact with the atoms and molecules in the photoresist, causing chemical changes in the photoresist. Since low-energy electrons are more likely to lose energy, they can more effectively transfer energy to the photoresist when interacting with the photoresist, thereby inducing a chemical reaction. This efficient energy transfer method makes the low-energy electrons more effective on the photoresist at the same number of electrons. 3. Because of the limitations of high-energy electron beams: In contrast, high-energy electron beams have strong penetrability. They can easily penetrate the photoresist to reach the substrate, and lose most of their energy on the substrate, generating heat. This strong penetrability will cause the exposure area to be too large, which will reduce the resolution of the lithography. In addition, if the amount of electrons is large, the substrate may be damaged by excessively high temperatures. Therefore, the application of high-energy electron beams in lithography is subject to certain restrictions. 4. Because of the advantages of low-energy electron irradiation lithography: Since low-energy electrons are more prone to inelastic scattering in photoresist and can transfer energy to photoresist more efficiently, low-energy electron irradiation lithography has an advantage in 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 great potential in nanoelectronics, nano-optical device manufacturing and other nanotechnology applications.

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

[0055] providing a substrate and a polymer solution;

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

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

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

[0059] In some embodiments, the heating treatment is performed at a temperature of 180° C. and for a time of 90 seconds.

[0060] The heating treatment in this embodiment is a pre-baking treatment, also known as soft baking, which is an important step in the photolithography process. Its main purpose is to volatilize the solvent in the photoresist by heating, thereby enhancing the adhesion between the photoresist and the substrate and eliminating the internal stress generated during the coating process, and reducing dust contamination. The high temperature of 180°C can quickly remove the residual moisture and solvent in the polymer in a short time (90s), avoid bubbles and cracks, thereby improving the accuracy and quality of the photolithography pattern. At the same time, it can optimize the performance of the photoresist, ensure that the photoresist pattern will not fall off or deform during the development and etching process, and make the photoresist form a more uniform coating on the silicon wafer, thereby improving the uniformity and consistency of the photolithography pattern. Moreover, the pre-baking time of 90 seconds is relatively short, which can shorten the time of the entire photolithography process and improve production efficiency. At the same time, the overall energy consumption is relatively low, which helps to reduce production costs. In addition, the stable pre-baking conditions can ensure that the photoresist performance between different batches is consistent, reduce the impact of batch differences on the final product, and by accurately controlling the pre-baking temperature and time, the dryness and performance of the photoresist can be more accurately controlled, and the controllability and stability of the process can be improved.

[0061] In some embodiments, a substrate covered with a polymer film is placed in a vacuum chamber of an electron cyclotron resonance plasma nano-surface processing system, a mask having a preset pattern is covered on the surface of the polymer film, and an aperture structure is arranged in front of the mask, and the steps of performing electron irradiation treatment specifically include:

[0062] Placing a substrate with a polymer film on its surface on a substrate rack in a vacuum chamber of an electron cyclotron resonance plasma nano-surface processing system, covering the surface of the polymer film with a mask having a preset pattern, providing an aperture structure in front of the mask, and evacuating the film to a preset value;

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

[0064] The substrate bias voltage is set to a positive bias voltage to attract electrons in the argon plasma to perform electron irradiation on the polymer film on the surface of the substrate 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 -4 Pa.

[0066] Setting the vacuum preset value in such a range can avoid the influence of impurity gases and ensure high purity during the photolithography process, so the cavity must reach a higher vacuum degree.

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

[0068] The substrate bias affects the depth of interaction between electrons and photoresist. If you want to make the depth of interaction of electrons greater, you can increase the irradiation voltage. Under the above substrate bias range, there are no defects such as pinholes in the area blocked by the mask, the size of the pattern is accurate and uniform, the step edges of each pattern are neat, the shape of the pattern after photolithography is slightly inverted trapezoidal, and there is no residual material in the center.

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

[0070] Different substrate currents will affect the dose of electrons acting on the photoresist, but the irradiation time has a more obvious effect on the photoresist and leaves more residues. Therefore, setting the above substrate current range to reduce the substrate current and make it highly controllable helps control the irradiation time, which can meet the charge amount for 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 development treatment time is 40 seconds, and the developer is selected from one or more of methyl isobutyl (methyl) ketone solution, isopropyl alcohol solution, and acetone solution.

[0073] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and are only for illustrating the present invention but not limiting the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0074] Example 1

[0075] The resistivity is less than 0.0015Ω .cm P type <100> Oriented single crystal silicon was selected as the substrate, and it was cut into 25mm×25mm size with a diamond pen, first ultrasonicated with acetone solution for 7min, then transferred to ethanol solution for ultrasonication for 7min, and finally ultrasonicated with deionized water for 7min. After cleaning, it was blown dry with a nitrogen gun; Figure 4 As shown, a KW-4A coating machine is used to evenly spin-coat 495KPMMA A2 photoresist on the silicon substrate: the parameters of the coating are set as a rotation speed of 4000 rpm, an initial rotation speed of 1000 rpm, and a rotation time of 45 s.

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

[0077] After the silicon substrate and the mask made by deep silicon etching process are placed on the substrate rack, a mechanical pump is used to pre-evacuate the pre-vacuum chamber. When the pressure in the chamber reaches 10 -2 Pa, the substrate holder is sent to the magnetic mirror position, and the molecular pump continues to work until the cavity pressure reaches the background vacuum degree of 4×10 -4 When the temperature is 0.045°C, argon gas is introduced into the cavity, the gas flow rate is adjusted to 12 sccm, the microwave power is adjusted to 70 W, and the left magnetic coil is 35.5 A. At this time, remote argon plasma is generated in the cavity. Then the substrate bias is set to +100 V, the substrate current is 0.5 mA, the baffle of the substrate rack is opened, and a time relay is connected in the passage. Before photolithography, the photolithography time is set to 1 s for the relay. After the time relay is turned on, the circuit is turned on. After the time reaches 1 s, the relay is disconnected.

[0078] The substrate after photolithography is placed in a developer for development. The developer used for PMMA as a positive photoresist is a mixed solution of methyl isobutyl ketone (MIBK) and isopropyl alcohol (IPA) solution, which is mixed in a ratio of 1:3. The development time is 40 seconds. After the development is completed, rinse with deionized water and soak for 1 minute to obtain the desired circular pattern. Figure 5 .

[0079] Example 2

[0080] The resistivity is less than 0.0015Ω . cm P type <100> Oriented single crystal silicon was selected as the substrate, and it was cut into 25mm×25mm size with a diamond pen, first ultrasonicated with acetone solution for 7min, then transferred to ethanol solution for ultrasonication for 7min, and finally ultrasonicated with deionized water for 7min. After cleaning, it was blown dry with a nitrogen gun; Figure 4As shown, a KW-4A coating machine is used to evenly spin-coat 495KPMMA A2 photoresist on the silicon substrate: the parameters of the coating are set as a rotation speed of 4000 rpm, an initial rotation speed of 1000 rpm, and a rotation time of 45 s.

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

[0082] After the silicon substrate and the mask made by deep silicon etching process are placed on the substrate rack, a mechanical pump is used to pre-evacuate the pre-vacuum chamber. When the pressure in the chamber reaches 10 -2 Pa, the substrate holder is sent to the magnetic mirror position, and the molecular pump continues to work until the cavity pressure reaches the background vacuum degree of 4×10 -4 When the temperature is 0.04 Pa, argon gas is introduced into the cavity, the gas flow rate is adjusted to 12 sccm, the microwave power is adjusted to 100 W, and the left magnetic coil is 35.5 A. At this time, remote argon plasma is generated in the cavity. Then the substrate bias is set to +100 V, the substrate current is 1.5 mA, the baffle of the substrate rack is opened, and a time relay is connected in the passage. Before photolithography, the photolithography time is set to 1 s for the relay. After the time relay is turned on, the circuit is turned on. After the time reaches 1 s, the relay is disconnected.

[0083] The substrate after photolithography is placed in a developer for development. The developer used for PMMA as a positive photoresist is a mixed solution of methyl isobutyl ketone (MIBK) and isopropyl alcohol (IPA) solution, which is mixed in a ratio of 1:3. The development time is 40 seconds. After the development is completed, it is rinsed with deionized water and soaked for 1 minute to obtain the desired square pattern. Figure 6 .

[0084] Example 3

[0085] The resistivity is less than 0.0015Ω . cm P type <100> Oriented single crystal silicon was selected as the substrate, and it was cut into 25mm×25mm size with a diamond pen, first ultrasonicated with acetone solution for 7min, then transferred to ethanol solution for ultrasonication for 7min, and finally ultrasonicated with deionized water for 7min. After cleaning, it was blown dry with a nitrogen gun; Figure 4 As shown, a KW-4A coating machine is used to evenly spin-coat 495KPMMA A2 photoresist on the silicon substrate: the parameters of the coating are set as a rotation speed of 4000 rpm, an initial rotation speed of 1000 rpm, and a rotation time of 45 s.

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

[0087] After the silicon substrate and the mask made by deep silicon etching process are placed on the substrate rack, a mechanical pump is used to pre-evacuate the pre-vacuum chamber. When the pressure in the chamber reaches 10 -2 Pa, the substrate holder is sent to the magnetic mirror position, and the molecular pump continues to work until the cavity pressure reaches the background vacuum degree of 4×10 -4 When the temperature is 0.04 Pa, argon gas is introduced into the cavity, the gas flow rate is adjusted to 12 sccm, the microwave power is adjusted to 100 W, and the left magnetic coil is 35.5 A. At this time, remote argon plasma is generated in the cavity. Then the substrate bias is set to +100 V, the substrate current is 1.5 mA, the baffle of the substrate rack is opened, and a time relay is connected in the passage. Before photolithography, the photolithography time is set to 1 s for the relay. After the time relay is turned on, the circuit is turned on. After the time reaches 1 s, the relay is disconnected.

[0088] The substrate after photolithography is placed in a developer for development. The developer used for PMMA as a positive photoresist is a mixed solution of methyl isobutyl ketone (MIBK) and isopropyl alcohol (IPA) solution, which is mixed in a ratio of 1:3. The development time is 40 seconds. After the development is completed, it is rinsed with deionized water and soaked for 1 minute to obtain the desired rectangular pattern. Figure 7 .

[0089] Example 4

[0090] Select silicon dioxide as the substrate, cut it into 25mm×25mm size with a diamond pen, first ultrasonicate it with acetone solution for 7min, then transfer it to ethanol solution for ultrasonicate for 7min, and finally ultrasonicate it with deionized water for 7min. After cleaning, blow dry it with a nitrogen gun; Figure 4 As shown, a KW-4A coating machine is used to evenly spin-coat 495K PMMA A2 photoresist on the above silicon dioxide substrate: the parameters of the coating are set as a rotation speed of 4000 rpm, an initial rotation speed of 1000 rpm, and a rotation time of 45 s.

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

[0092] After the silicon dioxide substrate and the mask made by deep silicon etching process are placed on the substrate rack, a mechanical pump is used to pre-evacuate the pre-vacuum chamber. When the chamber pressure reaches 10 -2 Pa, the substrate holder is sent to the magnetic mirror position, and the molecular pump continues to work until the cavity pressure reaches the background vacuum degree of 4×10 -4When the temperature is 0.04 Pa, argon gas is introduced into the cavity, the gas flow rate is adjusted to 12 sccm, the microwave power is adjusted to 100 W, and the left magnetic coil is 35.5 A. At this time, remote argon plasma is generated in the cavity. Then the substrate bias is set to +100 V, the substrate current is 1.5 mA, the baffle of the substrate rack is opened, and a time relay is connected in the passage. Before photolithography, the photolithography time is set to 1 s for the relay. After the time relay is turned on, the circuit is turned on. After the time reaches 1 s, the relay is disconnected.

[0093] The substrate after photolithography is placed in a developer for development. The developer used for PMMA as a positive photoresist is a mixed solution of methyl isobutyl ketone (MIBK) and isopropyl alcohol (IPA) solution, which is mixed in a ratio of 1:3. The development time is 40 seconds. After the development is completed, it is rinsed and soaked in deionized water for 1 minute to obtain the required circular pattern with a diameter of 150μm. Figure 8 .

[0094] Example 5

[0095] Select silicon dioxide as the substrate, cut it into 25mm×25mm size with a diamond pen, first ultrasonicate it with acetone solution for 7min, then transfer it to ethanol solution for ultrasonicate for 7min, and finally ultrasonicate it with deionized water for 7min. After cleaning, blow dry it with a nitrogen gun; Figure 4 As shown, a KW-4A coating machine is used to evenly spin-coat 495K PMMA A2 photoresist on the above silicon dioxide substrate: the parameters of the coating are set as a rotation speed of 4000 rpm, an initial rotation speed of 1000 rpm, and a rotation time of 45 s.

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

[0097] After the silicon dioxide substrate and the mask made by deep silicon etching process are placed on the substrate rack, a mechanical pump is used to pre-evacuate the pre-vacuum chamber. When the chamber pressure reaches 10 -2 Pa, the substrate holder is sent to the magnetic mirror position, and the molecular pump continues to work until the cavity pressure reaches the background vacuum degree of 4×10 -4 When the temperature is 0.04 Pa, argon gas is introduced into the cavity, the gas flow rate is adjusted to 12 sccm, the microwave power is adjusted to 100 W, and the left magnetic coil is 35.5 A. At this time, remote argon plasma is generated in the cavity. Then the substrate bias is set to +100 V, the substrate current is 1.5 mA, the baffle of the substrate rack is opened, and a time relay is connected in the passage. Before photolithography, the photolithography time is set to 1 s for the relay. After the time relay is turned on, the circuit is turned on. After the time reaches 1 s, the relay is disconnected.

[0098] The substrate after photolithography is placed in a developer for development. The developer used for PMMA as a positive photoresist is a mixed solution of methyl isobutyl ketone (MIBK) and isopropyl alcohol (IPA) solution, which is mixed in a ratio of 1:3. The development time is 40 seconds. After the development is completed, it is rinsed and soaked in deionized water for 1 minute to obtain the required square pattern with a side length of 50μm. Fig. 9 .

[0099] Example 6

[0100] The resistivity is less than 0.0015Ω . cm P type <100> Oriented single crystal silicon was selected as the substrate, and it was cut into 25mm×25mm size with a diamond pen, first ultrasonicated with acetone solution for 7min, then transferred to ethanol solution for ultrasonication for 7min, and finally ultrasonicated with deionized water for 7min. After cleaning, it was blown dry with a nitrogen gun; Fig.10 As shown, a KW-4A coating machine is used to evenly spin-coat 495KPMMA A2 photoresist on the silicon substrate: the parameters of the coating are set as a rotation speed of 4000 rpm, an initial rotation speed of 1000 rpm, and a rotation time of 45 s.

[0101] The above-mentioned substrate with glue was heated at 180°C for 90 seconds. This process was carried out in a yellow light clean room.

[0102] After the silicon substrate and the mask made by deep silicon etching process are placed on the substrate rack, a mechanical pump is used to pre-evacuate the pre-vacuum chamber. When the pressure in the chamber reaches 10 -2 Pa, the substrate holder is sent to the magnetic mirror position, and the molecular pump continues to work until the cavity pressure reaches the background vacuum degree of 4×10 -4 When Pa, argon gas is introduced into the cavity, the gas flow rate is adjusted to 12sccm, the microwave power is adjusted to 100W, the left, middle and right magnetic coils are 38A, 22A, and 23A respectively, and remote argon plasma is generated in the cavity. Then the substrate bias is set to +100V, the substrate current is 30mA, the baffle of the substrate rack is opened, and a time relay is connected in the passage. 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 after the time reaches 30s, the relay is disconnected.

[0103] The substrate after photolithography is placed in a developer for development. PMMA is then transformed into a negative photoresist. The developer used is an acetone solution. The development time is 40 seconds. After the development is completed, it is rinsed and soaked in deionized water for 1 minute. The electron irradiated area is retained, while the area blocked by the mask will be washed away by acetone, and the desired circular pattern can be obtained. Fig.11 .

[0104] Example 7

[0105] The resistivity is less than 0.0015Ω . cm P type <100> Oriented single crystal silicon was selected as the substrate, and it was cut into 25mm×25mm size with a diamond pen, first ultrasonicated with acetone solution for 7min, then transferred to ethanol solution for ultrasonication for 7min, and finally ultrasonicated with deionized water for 7min. After cleaning, it was blown dry with a nitrogen gun; Fig.10 As shown, a KW-4A coating machine is used to evenly spin-coat 495KPMMA A2 photoresist on the silicon substrate: the parameters of the coating are set as a rotation speed of 4000 rpm, an initial rotation speed of 1000 rpm, and a rotation time of 45 s.

[0106] The above-mentioned substrate with glue was heated at 180°C for 90 seconds. This process was carried out in a yellow light clean room.

[0107] After the silicon substrate and the mask made by deep silicon etching process are placed on the substrate rack, a mechanical pump is used to pre-evacuate the pre-vacuum chamber. When the pressure in the chamber reaches 10 -2 Pa, the substrate holder is sent to the magnetic mirror position, and the molecular pump continues to work until the cavity pressure reaches the background vacuum degree of 4×10 -4 When Pa, argon gas is introduced into the cavity, the gas flow rate is adjusted to 12sccm, the microwave power is adjusted to 100W, the left, middle and right magnetic coils are 38A, 22A and 17A respectively, and remote argon plasma is generated in the cavity. Then the substrate bias is set to +100V, the substrate current is 30mA, the baffle of the substrate rack is opened, and a time relay is connected in the passage. 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 after the time reaches 30s, the relay is disconnected.

[0108] The substrate after photolithography is placed in a developer for development. PMMA is then transformed into a negative photoresist. The developer used is an acetone solution. The development time is 40 seconds. After the development is completed, it is rinsed and soaked in deionized water for 1 minute. The electron irradiated area is retained, while the area blocked by the mask is washed away by acetone, and the desired square pattern can be obtained. Fig.12 .

[0109] Example 8

[0110] The resistivity is less than 0.0015Ω . cm P type <100> Oriented single crystal silicon was selected as the substrate, and it was cut into 25mm×25mm size with a diamond pen, first ultrasonicated with acetone solution for 7min, then transferred to ethanol solution for ultrasonication for 7min, and finally ultrasonicated with deionized water for 7min. After cleaning, it was blown dry with a nitrogen gun; Fig.10As shown, a KW-4A coating machine is used to evenly spin-coat 495KPMMA A2 photoresist on the silicon substrate: the parameters of the coating are set as a rotation speed of 4000 rpm, an initial rotation speed of 1000 rpm, and a rotation time of 45 s.

[0111] The above-mentioned substrate with glue was heated at 180°C for 90 seconds. This process was carried out in a yellow light clean room.

[0112] After the silicon substrate and the mask made by deep silicon etching process are placed on the substrate rack, a mechanical pump is used to pre-evacuate the pre-vacuum chamber. When the pressure in the chamber reaches 10 -2 Pa, the substrate holder is sent to the magnetic mirror position, and the molecular pump continues to work until the cavity pressure reaches the background vacuum degree of 4×10 -4 When Pa, argon gas is introduced into the cavity, the gas flow rate is adjusted to 12sccm, the microwave power is adjusted to 100W, the left, middle and right magnetic coils are 38A, 22A and 17A respectively, and remote argon plasma is generated in the cavity. Then the substrate bias is set to +100V, the substrate current is 30mA, the baffle of the substrate rack is opened, and a time relay is connected in the passage. 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 after the time reaches 30s, the relay is disconnected.

[0113] The substrate after photolithography is placed in a developer for development. PMMA is then transformed into a negative photoresist. The developer used is an acetone solution. The development time is 40 seconds. After the development is completed, it is rinsed with deionized water and soaked for 1 minute. The electron irradiated area is retained, while the area blocked by the mask will be washed away by acetone, and the desired rectangular pattern can be obtained. Fig.13 .

[0114] Example 9

[0115] Select silicon dioxide as the substrate, cut it into 25mm×25mm size with a diamond pen, first ultrasonicate it with acetone solution for 7min, then transfer it to ethanol solution for ultrasonicate for 7min, and finally ultrasonicate it with deionized water for 7min. After cleaning, blow dry it with a nitrogen gun; Fig.10 As shown, a KW-4A coating machine is used to evenly spin-coat 495K PMMA A2 photoresist on the above silicon dioxide substrate: the parameters of the coating are set as a rotation speed of 4000 rpm, an initial rotation speed of 1000 rpm, and a rotation time of 45 s.

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

[0117] After the silicon dioxide substrate and the mask made by deep silicon etching process are placed on the substrate rack, a mechanical pump is used to pre-evacuate the pre-vacuum chamber. When the chamber pressure reaches 10 -2 Pa, the substrate holder is sent to the magnetic mirror position, and the molecular pump continues to work until the cavity pressure reaches the background vacuum degree of 4×10 -4 When Pa, argon gas is introduced into the cavity, the gas flow rate is adjusted to 12sccm, the microwave power is adjusted to 100W, the left, middle and right magnetic coils are 38A, 22A and 16A respectively, and remote argon plasma is generated in the cavity. Then the substrate bias is set to +100V, the substrate current is 20mA, the baffle of the substrate rack is opened, and a time relay is connected in the passage. 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 after the time reaches 30s, the relay is disconnected.

[0118] The substrate after photolithography is placed in a developer for development. PMMA is then transformed into a negative photoresist. The developer used is an acetone solution. The development time is 40 seconds. After the development is completed, it is rinsed and soaked in deionized water for 1 minute. The electron irradiated area is retained, while the area blocked by the mask will be washed away by acetone, and the desired circular pattern can be obtained. Fig.14 .

[0119] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A low-energy electron irradiation lithography method, characterized in that: The low-energy electron irradiation lithography method comprises the following steps: Providing a substrate having a surface covered with a polymer film; Placing a substrate with a polymer film on its surface in a vacuum chamber of an electron cyclotron resonance plasma nano-surface processing system, covering the surface of the polymer film with a mask having a preset pattern, arranging an aperture structure in front of the mask, and performing electron irradiation treatment; Performing a developing process on the substrate after the electron irradiation process in a developer to obtain a desired pattern on the substrate; The electron irradiation treatment adopts remote plasma, the diameter range of the central hole of the aperture structure is 0-35 mm, and the irradiation current of the electron irradiation treatment is 0.5-5 mA.

2. The low-energy electron irradiation lithography method according to claim 1, characterized in that: The method of providing a substrate having a surface covered with a polymer film specifically comprises the following steps: providing a substrate and a polymer solution; The polymer solution is transferred to the surface of the substrate, and dried and heated to obtain the substrate with the surface covered with a polymer film.

3. The low-energy electron irradiation lithography method according to claim 1, characterized in that: The polymer solution comprises a polymer and a solvent, wherein the polymer is selected from one or more of polymethyl methacrylate, polymethyl methacrylate, epoxy resin, cyclized polybutadiene, photosensitive resin, poly-α-methylstyrene, polyisobutylene, polymethyl ethyl ketone, and poly-α-ethyl cyanoacrylate.

4. The low-energy electron irradiation lithography method according to claim 2, characterized in that: The temperature of the heating treatment is 180° C., and the time of the heating treatment is 90 seconds.

5. The low-energy electron irradiation lithography method according to claim 1, characterized in that: The steps of placing a substrate covered with a polymer film on the surface in a vacuum chamber of an electron cyclotron resonance plasma nano-surface processing system, covering the surface of the polymer film with a mask having a preset pattern, and providing an aperture structure in front of the mask, and performing electron irradiation treatment specifically include: Placing a substrate with a polymer film on its surface on a substrate rack in a vacuum chamber of an electron cyclotron resonance plasma nano-surface processing system, covering the surface of the polymer film with a mask having a preset pattern, providing an aperture structure in front of the mask, and evacuating the film to a preset value; Argon gas is introduced, and under the combined action of microwaves and magnetic fields, the argon gas is ionized into argon plasma; The substrate bias voltage is set to a positive bias voltage to attract electrons in the argon plasma to perform electron irradiation on the polymer film on the surface of the substrate and the mask with a preset pattern on the polymer film.

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

7. The low-energy electron irradiation lithography method according to claim 5, characterized in that: The substrate bias voltage is 50-200V.

8. The low-energy electron irradiation lithography method according to claim 5, characterized in that: The step of setting the substrate bias voltage to a positive bias voltage also includes the step of setting the substrate current: the substrate current is 0.5-120mA.

9. The low-energy electron irradiation lithography method according to claim 5, characterized in that: The time of the electron irradiation treatment is 1-30s.

10. The low-energy electron irradiation lithography method according to claim 1, characterized in that: The development treatment time is 40 seconds, and the developer is selected from one or more of methyl isobutyl ketone solution, isopropyl alcohol solution, and acetone solution.

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