A plasma atomic layer deposition apparatus and method based on a low-frequency hollow cathode

Abstract

The application discloses a kind of plasma atomic layer deposition device and method based on low-frequency hollow cathode, applied to semiconductor device manufacturing field, and deposition device includes reaction cavity, low-frequency power supply, hollow cathode module, deposition substrate, reaction gas supply system, precursor supply system and exhaust system, hollow cathode module includes hollow chamber and hollow cathode tube placed in hollow chamber, the bottom of hollow chamber is communicated with the top of reaction cavity, hole is opened in the wall of hollow cathode tube, low-frequency power supply is connected with hollow cathode tube, deposition substrate is placed in reaction cavity and is located directly below hollow cathode module, reaction gas supply system, precursor supply system, exhaust system are connected with reaction cavity respectively.The application simultaneously maintains high concentration chemical free radical generation ability under relatively high process pressure condition, and significantly reduces the direct bombardment influence of ion energy to deposition substrate.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device manufacturing technology, specifically a plasma atomic layer deposition apparatus and method based on a low-frequency hollow cathode. Background Technology

[0002] Currently, with the continuous miniaturization of advanced semiconductor device structures, such as FinFET, GAAFET, 3D NAND, and advanced packaging structures, higher demands are placed on high-quality thin film deposition technologies. Traditional physical vapor deposition (PVD) and chemical vapor deposition (CVD) methods struggle to achieve uniform coating coverage in complex structures. Plasma-atom layer deposition (PEALD) technology, by using specific precursors and plasmas, can precisely control reaction conditions to achieve uniform thin film growth, even in deep and narrow structures. In the semiconductor device manufacturing process, PEALD technology is widely used to form key functional thin films such as high-dielectric-constant gate dielectric layers, metal gate layers, diffusion barrier layers, passivation layers, and capacitor dielectric layers. , , , , Materials, etc.

[0003] Existing plasma atomic layer deposition technologies mainly include capacitively coupled plasma (CCP), inductively coupled plasma (ICP), and remote plasma. CCP and planar ICP plasma sources are typically located within the reaction chamber and close to the substrate surface. They generate plasma by directly exciting the reactive gas using a radio frequency electric field. During the process, high-energy ions can directly bombard the substrate, leading to surface defects, dielectric layer damage, or reliability degradation. Remote plasma, on the other hand, places the plasma generation area upstream of the substrate, allowing active species to be transported into the reaction area, thus reducing the impact of direct plasma bombardment. However, existing remote plasma sources have limited effective reaction area, failing to meet the requirements of large-size wafers or panel deposition. Multipolar ICP... To expand plasma coverage, plasma systems typically require multiple radio frequency (RF) power supplies connected in series. In addition to additional electromagnetic interference suppression devices, the plasma inhomogeneity caused by standing wave effects must also be addressed, resulting in complex system structure, significantly increased costs, and difficulty in controlling process stability. To obtain high concentrations of free radicals, ICP systems are limited to low-pressure operating conditions to maintain their ionization efficiency. However, the high flow rate associated with the low-pressure environment shortens the contact frequency between chemical particles and the substrate to be treated, resulting in limited chemisorption kinetics of reaction precursors on complex surface structures, making it difficult to achieve self-limiting saturated adsorption, thereby affecting the step coverage capability and reliability of the process. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a plasma atomic layer deposition apparatus and method based on a low-frequency hollow cathode, which maintains a high concentration of chemical free radical generation capability under relatively high process pressure conditions, and significantly reduces the direct bombardment effect of ion energy on the deposition substrate.

[0005] The technical solution of this invention is as follows: A plasma atomic layer deposition apparatus based on a low-frequency hollow cathode includes a reaction chamber, a low-frequency power supply, a hollow cathode module, a deposition substrate, a reaction gas supply system, a precursor supply system, an exhaust system, and a vacuum gauge. The bottom end of the hollow cathode module is connected to the top end of the reaction chamber, and the two are interconnected. The deposition substrate is placed inside the reaction chamber and located directly below the hollow cathode module. The output end of the reaction gas supply system is connected to the reaction gas inlet on the hollow cathode module, and the output end of the precursor supply system is connected to the precursor inlet on the reaction chamber. The exhaust system and the vacuum gauge are both connected to the reaction chamber. The hollow cathode module includes a hollow chamber and a hollow cathode tube placed inside the hollow chamber. The top of the hollow chamber is a closed structure, and the bottom is provided with a plasma outlet. The upper part of the side wall of the hollow chamber is provided with a reaction gas inlet. Multiple rings of evenly distributed holes are opened on the tube wall from top to bottom. The cathode potential end of the low-frequency power supply is connected to the hollow cathode tube, and the anode potential end of the low-frequency power supply is connected to the hollow chamber. The hollow chamber is electrically connected to the reaction chamber and grounded. The low-frequency power supply drives the hollow cathode module to generate plasma.

[0006] The low-frequency power supply has an output frequency range of 1kHz to 500kHz and an output power of 50W to 1500W.

[0007] The hollow cathode tube is a stainless steel hollow cathode tube or an aluminum alloy hollow cathode tube, and the distance between the bottom end of the hollow cathode tube and the top end of the deposition substrate is 10mm to 500mm.

[0008] There are multiple hollow cathode modules and low-frequency power supplies. Each hollow cathode module is connected to a corresponding low-frequency power supply, and the multiple hollow cathode modules are evenly arranged above the deposition substrate.

[0009] A heating plate is provided inside the reaction chamber, and the deposition substrate is placed on the heating plate.

[0010] The reaction gas supply system includes a reaction gas delivery pipe, a mass flow controller, and a normally closed valve. The input end of the reaction gas delivery pipe is connected to a reaction gas cylinder, and the output end of the reaction gas delivery pipe is connected to the reaction gas inlet on the hollow cathode module. The mass flow controller and the normally closed valve are both located on the reaction gas delivery pipe, with the normally closed valve adjacent to the output end of the reaction gas delivery pipe. The reaction gas cylinder is selected from oxygen cylinders, nitrogen cylinders, ammonia cylinders, hydrogen cylinders, or inert gas cylinders.

[0011] The precursor supply system includes a precursor delivery pipe and an ALD valve installed on the precursor delivery pipe. The input end of the precursor delivery pipe is a precursor gas inlet, and the output end of the precursor delivery pipe is connected to the precursor gas inlet on the reaction chamber.

[0012] The exhaust system includes an exhaust pipe, a butterfly valve and an angle valve installed on the exhaust pipe, and a vacuum pump connected to the exhaust pipe outlet. The exhaust pipe inlet is connected to the reaction chamber and communicates with the interior of the reaction chamber.

[0013] The deposition method using a plasma atomic layer deposition apparatus specifically includes the following steps: (1) Turn on the precursor supply system and heating plate. Set the heating temperature of the heating plate to 100℃~450℃. The precursor gas enters the reaction chamber and is adsorbed on the surface of the heated deposition substrate. (2) After the precursor adsorption is completed, the unadsorbed precursor gas is discharged using the exhaust system. Then, the pressure in the hollow cavity of the hollow cathode module is adjusted using the exhaust system, and the exhaust system is then closed. (3) Turn on the reaction gas supply system and the low frequency power supply. The reaction gas flows into the hollow cavity of the hollow cathode module and enters the hollow cathode tube through the hole on the hollow cathode tube. The low frequency power supply drives the hollow cathode tube to generate electrons. The electrons collide with the reaction gas to form a plasma of the reaction gas. The plasma of the reaction gas diffuses out through the hole on the hollow cathode tube and diffuses into the reaction cavity through the reaction gas inlet at the bottom of the hollow cavity. The plasma of the reaction gas reacts with the precursor adsorbed on the surface of the deposition substrate to form an atomic layer. (4) After the reaction is complete, the reaction byproducts can be discharged using the exhaust system.

[0014] The exhaust system adjusts the pressure inside the hollow cavity of the hollow cathode module to 0.01 to 10 Torr. The distance between the bottom end of the hollow cathode tube and the top end of the deposition substrate is adjusted according to the pressure inside the hollow cavity and decreases as the pressure inside the hollow cavity increases.

[0015] Advantages of this invention: (1) The present invention uses a low-frequency power supply to drive the hollow cathode module to generate plasma. Compared with radio frequency (RF) power supply, the low-frequency excitation method can effectively reduce the plasma sheath voltage and suppress the generation of high-energy ions, thereby reducing physical bombardment damage to the substrate surface.

[0016] (2) The hollow cathode module of the present invention is provided with a hollow cavity. Electrons are reflected multiple times on the inner wall of the hollow cavity, and the effective electron path length can be increased from a few millimeters of single sheath thickness to more than tens of millimeters, thereby increasing the collision frequency per unit volume by 3 to 10 times. Under low-frequency power supply driving conditions, stable discharge can be maintained in a relatively high pressure range of 0.1 to 5 Torr, and the electron density can reach about 1 × 10 11 ~5×10 12 cm -3 The electron temperature is about -5eV, and the dissociation rate of the reaction gas can reach 40-80%. Since the plasma is mainly confined inside the hollow cavity, the energy of the ions escaping into the reaction zone inside the reaction cavity is lower than 10-20eV. As a result, the plasma entering the deposition area of ​​the deposition substrate is mainly composed of neutral free radicals, thus significantly reducing the physical bombardment of the deposition substrate.

[0017] (3) In the hollow cathode module of the present invention, the cathode in the hollow cavity is a hollow cathode tube. The inner wall of the hollow cathode tube is at a negative potential. When electrons enter the cathode sheath region on the opposite side, they are reflected by the electric field and return to their original direction to continue moving. Therefore, electrons oscillate back and forth between the inner walls of the hollow cathode tube multiple times, instead of drifting in one direction and dissipating in the traditional flat plate electrode structure. This back and forth oscillation phenomenon further prolongs the effective movement path of electrons in the discharge area. The increase in the electron movement path significantly increases the probability of collision between electrons and reactive gas molecules. During the collision, gas ionization reaction occurs, generating new electrons and ions, which in turn forms an avalanche multiplication effect and increases the plasma density.

[0018] (4) The hollow cathode tube of the present invention has holes on its tube wall. The hole structure can realize the uniform introduction of reaction gas and release the active free radicals generated inside the hollow cathode tube to the outside. On the other hand, it can adjust the local electric field distribution and avoid local arc discharge or discharge instability caused by electric field concentration. At the same time, the porous structure is conducive to the outward diffusion of active plasma and is suitable for remote plasma process to reduce the damage caused by high-energy ions directly bombarding the deposition substrate.

[0019] (5) The present invention places the hollow cathode module upstream of the reaction zone of the deposition substrate, and by setting the distance between the hollow cathode tube and the deposition substrate, the generated plasma is mainly confined to the area where the hollow cathode module is located, so that the plasma generation area and the reaction zone of the deposition substrate are separated from each other, and the plasma is attenuated by collision scattering and recombination neutralization during the transmission process, thereby forming a reaction environment dominated by neutral free radicals at the deposition substrate, thus significantly reducing the physical bombardment of the deposition substrate.

[0020] (6) The hollow cathode module of the present invention can be modularly designed, with multiple hollow cathode modules evenly arranged above the deposition substrate. By increasing the number of hollow cathode modules, the effective coverage area of ​​the plasma can be expanded, without the need to configure multiple sets of radio frequency power supplies or complex impedance matching networks, thus making it suitable for the fabrication process of large-area deposition substrates of 12 inches or more.

[0021] The plasma atomic layer deposition apparatus disclosed in this invention is suitable for the deposition of critical functional thin films in the semiconductor device manufacturing process, including but not limited to: (1) high dielectric constant gate dielectric layers, such as , , (2) Metal gate material, such as TiN, TaN, WN; (3) Diffusion barrier layer of semiconductor device, such as TiN or TaN; (4) Passivation layer or insulating layer of semiconductor device, such as or (5) Dielectric thin film in semiconductor capacitor structure; Semiconductor devices include, but are not limited to, MOSFET, FinFET, GAAFET, DRAM capacitor, 3D NAND memory and advanced packaging structure. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0023] Figure 2 This is a cross-sectional view of the hollow cathode module in this invention, with arrows indicating the direction of the reaction gas flow.

[0024] Figure 3 This is a perspective view of the hollow cathode tube in this invention.

[0025] Figure 4 This is a schematic diagram of the modular hollow cathode module of the present invention connected to the reaction chamber.

[0026] Reference numerals: 1-Reaction chamber, 2-Low-frequency power supply, 21-Cathode potential terminal of low-frequency power supply, 22-Anode potential terminal of low-frequency power supply, 3-Hollow cathode module, 31-Hollow chamber, 32-Hollow cathode tube, 33-Pore, 4-Deposition substrate, 5-Heating plate, 6-Pirani vacuum gauge, 7-Reaction gas delivery pipe, 8-Mass flow controller, 9-Normally closed valve, 10-Precursor delivery pipe, 11-ALD valve, 12-Exhaust pipe, 13-Butterfly valve, 14-Angle valve, 15-Dry vacuum pump. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0028] See Figure 1 A plasma atomic layer deposition apparatus based on a low-frequency hollow cathode includes a reaction chamber 1, a low-frequency power supply 2, a hollow cathode module 3, a deposition substrate 4, a heating plate 5, a reaction gas supply system, a precursor supply system, an exhaust system, and a Pirani vacuum gauge 6. The bottom end of the hollow cathode module 3 is connected to the top end of the reaction chamber 1 and the two are interconnected. The deposition substrate 4 is placed on the heating plate 5. Both the deposition substrate 4 and the heating plate 5 are placed inside the reaction chamber 1 and located directly below the hollow cathode module 3. Hollow cathode module 3 (see) Figure 2The device includes a hollow chamber 31 and a hollow cathode tube 32 placed inside the hollow chamber 31. The top of the hollow chamber 31 is a closed structure, and the bottom is provided with a plasma outlet. The upper part of the side wall of the hollow chamber 31 is provided with a reaction gas inlet. The hollow cathode tube 32 (see...) Figure 3 The hollow cathode module 3 has multiple evenly distributed holes 33 on its tube wall from top to bottom. The cathode potential end 21 of the low-frequency power supply 2 is connected to the hollow cathode tube 32, and the anode potential end 22 of the low-frequency power supply 2 is connected to the hollow chamber 31. The hollow chamber 31 is electrically connected to the reaction chamber 1 and grounded. The low-frequency power supply 2 drives the hollow cathode module 3 to generate plasma. The output frequency range of the low-frequency power supply 2 is 1kHz to 500kHz, and the output power is 50W to 1500W. Preferably, the output frequency range is 10kHz to 400kHz. The hollow cathode tube 32 is a stainless steel hollow cathode tube or an aluminum alloy hollow cathode tube. The distance between the bottom end of the hollow cathode tube 32 and the top end of the deposition substrate 4 is 10mm to 500mm, preferably 50mm to 400mm. The reaction gas supply system includes a reaction gas delivery pipe 7, a mass flow controller 8, and a normally closed valve 9. The input end of the reaction gas delivery pipe 7 is connected to the reaction gas cylinder, and the output end of the reaction gas delivery pipe 7 is connected to the reaction gas inlet on the hollow cathode module 3. The mass flow controller 8 and the normally closed valve 9 are both installed on the reaction gas delivery pipe 7, and the normally closed valve 9 is adjacent to the output end of the reaction gas delivery pipe 7. The reaction gas cylinder is selected from oxygen cylinders, nitrogen cylinders, ammonia cylinders, hydrogen cylinders, or inert gas cylinders. The precursor supply system includes a precursor delivery pipe 10 and an ALD valve 11 installed on the precursor delivery pipe 10. The input end of the precursor delivery pipe 10 is a precursor gas inlet, and the output end of the precursor delivery pipe 10 is connected to the precursor gas inlet on the reaction chamber 1. The exhaust system includes an exhaust pipe 12, a butterfly valve 13 and an angle valve 14 installed on the exhaust pipe 12, and a dry vacuum pump 15 connected to the outlet of the exhaust pipe 12. The inlet of the exhaust pipe 12 is connected to the reaction chamber 1 and communicates with the interior of the reaction chamber 1. A Pirani vacuum gauge 6 is connected to the reaction chamber 1 and is used to collect the gas pressure inside the reaction chamber 1.

[0029] See Figure 4 When performing atomic layer deposition on a large-area deposition substrate, multiple hollow cathode modules 3 and low-frequency power supplies 2 are provided, with each hollow cathode module 3 connected to a corresponding low-frequency power supply 2. Figure 4 The seven hollow cathode modules 3 are all connected to the top of the reaction chamber 1 and are evenly arranged directly above the deposition substrate 4.

[0030] Example 1

[0031] one, The deposition method using a plasma atomic layer deposition apparatus specifically includes the following steps: (1) Turn on the precursor supply system and heating plate 5. The heating temperature of heating plate 5 is set to 200°C. The precursor trimethylaluminum (TMA) pulse enters the reaction chamber 1 and is adsorbed on the surface of the heated deposition substrate 4. The pulse time is 0.06s. (2) After the precursor adsorption is completed, the unadsorbed TMA is discharged using the exhaust system (time is 5s). Then, the pressure in the hollow chamber 31 of the hollow cathode module is adjusted to 0.1 Torr using the exhaust system and then the exhaust system is turned off. The distance between the bottom end of the hollow cathode tube 32 and the top end of the deposition substrate 4 is adjusted according to the pressure in the hollow chamber 31 and decreases as the pressure in the hollow chamber 31 increases. In this embodiment, the distance between the bottom end of the hollow cathode tube 32 and the top end of the deposition substrate 4 is 150 mm. (3) Turn on the reaction gas supply system and the low frequency power supply 2. The output frequency of the low frequency power supply 2 is 40kHz and the output power is 100W. The flow rate of the reaction gas oxygen is 100sccm. The oxygen flows into the hollow chamber 31 of the hollow cathode module 3 and enters the hollow cathode tube 32 through the hole 33 on the hollow cathode tube 32 (outer diameter is 30 mm and length is 100 mm). The low frequency power supply 2 drives the hollow cathode tube 32 to generate electrons. The electrons collide with the oxygen to form oxygen plasma. The oxygen plasma diffuses out through the hole 33 on the hollow cathode tube 32 and diffuses into the reaction chamber 1 through the reaction gas inlet at the bottom of the hollow chamber 31. The oxygen plasma reacts with the precursor adsorbed on the surface of the deposition substrate 4 to form an atomic layer. The reaction time is 5s. (4) After the reaction is complete, the reaction byproducts can be discharged using the exhaust system in 5 seconds; (5) Repeat steps (1)-(4) 300 times.

[0032] The atomic layer deposition results obtained under the above conditions are: growth rate of approximately 1.74 Å / cycle; atomic layer thickness uniformity on the 8-inch deposition substrate better than ±2%; and atomic layer refractive index of 1.64.

[0033] II. Performance Analysis: To verify the technical effectiveness of the hollow cathode module structure (HCD-type PEALD) of this invention, a comparative experiment was conducted with a traditional ICP-type PEALD structure under the same deposition conditions. Example 1 and the traditional ICP-type PEALD structure were prepared... The comparison results are shown in Table 1 below.

[0034] Table 1

[0035] As can be seen from the comparison of deposition results in Table 1 above: 1. Under the same number of cycles, HCD-type PEALD has a higher deposition thickness, indicating better deposition efficiency per unit cycle; 2. Under the same output power conditions, the growth rate of HCD-type PEALD is increased by about 6.1% compared with ICP-type PEALD, indicating that the HCD-type PEALD structure of the present invention improves gas dissociation efficiency and surface reaction efficiency. 3. The uniformity of the HCD-type PEALD structure improved by about 0.5% in this invention, indicating that the spatial distribution of free radicals is more uniform; 4. The refractive index of the HCD-type PEALD structure of this invention is improved, indicating that the compactness of the thin film is improved; 5. The HCD-type PEALD structure of this invention has a lower MSE, indicating better optical fitting quality and a more uniform and stable film structure.

[0036] In summary, the HCD-type PEALD structure of the present invention can improve the unit cycle deposition rate and enhance film uniformity and optical properties under the same deposition conditions, thereby improving deposition quality.

[0037] Example 2

[0038] one, The deposition method of the gate dielectric layer plasma atomic layer deposition apparatus is the same as that in Example 1, except that: The heating temperature of the heating plate 5 in step (1) is set to 250℃; the precursor used is tetrakis(dimethylamino)hafnium(IV), i.e., TDMAHf; the pulse time is 0.3s; The exhaust time of the exhaust system in step (2) is 3s, and the pressure in the hollow chamber 31 of the hollow cathode module is 0.2 Torr; In step (3), the low-frequency power supply 2 has an output frequency of 40kHz and an output power of 600W; the reaction gas supplied by the reaction gas supply system is oxygen, and the reaction time is 3s. The exhaust system in step (4) will discharge the reaction byproducts for 3 seconds; The cycle in step (5) is repeated 150 times to obtain a thickness of approximately 15 nm. film.

[0039] II. Performance Analysis: The deposited material was observed using an ellipsometry. Thickness and optical properties of the thin film were measured. The film thickness was determined to be 15.2 nm through optical model fitting. The refractive index n = 1.97 was measured at a wavelength of 633 nm. The model fitting error Fit Diff = 0.0006, indicating that the fitting results are reliable. The refractive index value is consistent with that of high-density ALD. The consistent typical range of the thin film indicates that the deposition... The film exhibits good density and uniformity.

[0040] To verify the chemical composition of the deposited thin film, X-ray photoelectron spectroscopy (XPS) testing of thin films: XPS survey spectrum showing the fabricated thin films. The main elements in the thin film sample were Hf and O, with no obvious peaks of impurity elements such as carbon or nitrogen detected. XPS quantitative analysis showed that the atomic percentages of Hf and O were 26.9% and 73.1%, respectively, close to... The stoichiometric ratio indicates that the deposited The thin film has high chemical purity and good oxidation state.

[0041] Experimental results show that the plasma atomic layer deposition apparatus of the present invention can achieve high-quality thin film deposition while reducing ion bombardment damage, and is suitable for advanced semiconductor device manufacturing.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A plasma atomic layer deposition device based on a low-frequency hollow cathode, characterized in that: The device includes a reaction chamber, a low-frequency power supply, a hollow cathode module, a deposition substrate, a reaction gas supply system, a precursor supply system, an exhaust system, and a vacuum gauge. The bottom end of the hollow cathode module is connected to the top end of the reaction chamber, and the two are interconnected. The deposition substrate is placed inside the reaction chamber and located directly below the hollow cathode module. The output end of the reaction gas supply system is connected to the reaction gas inlet on the hollow cathode module, and the output end of the precursor supply system is connected to the precursor inlet on the reaction chamber. The exhaust system and the vacuum gauge are both connected to the reaction chamber. The hollow cathode module includes a hollow chamber and a hollow cathode tube placed inside the hollow chamber. The top of the hollow chamber is a closed structure, and the bottom is provided with a plasma outlet. The upper part of the side wall of the hollow chamber is provided with a reaction gas inlet. Multiple rings of evenly distributed holes are opened on the tube wall from top to bottom. The cathode potential end of the low-frequency power supply is connected to the hollow cathode tube, and the anode potential end of the low-frequency power supply is connected to the hollow chamber. The hollow chamber is electrically connected to the reaction chamber and grounded. The low-frequency power supply drives the hollow cathode module to generate plasma.

2. The plasma atomic layer deposition apparatus based on a low-frequency hollow cathode according to claim 1, characterized in that: The low-frequency power supply has an output frequency range of 1kHz to 500kHz and an output power of 50W to 1500W.

3. The plasma atomic layer deposition apparatus based on a low-frequency hollow cathode according to claim 1, characterized in that: The hollow cathode tube is a stainless steel hollow cathode tube or an aluminum alloy hollow cathode tube, and the distance between the bottom end of the hollow cathode tube and the top end of the deposition substrate is 10mm to 500mm.

4. The plasma atomic layer deposition apparatus based on a low-frequency hollow cathode according to claim 1, characterized in that: There are multiple hollow cathode modules and low-frequency power supplies. Each hollow cathode module is connected to a corresponding low-frequency power supply, and the multiple hollow cathode modules are evenly arranged above the deposition substrate.

5. The plasma atomic layer deposition apparatus based on a low-frequency hollow cathode according to claim 1, characterized in that: A heating plate is provided inside the reaction chamber, and the deposition substrate is placed on the heating plate.

6. The plasma atomic layer deposition apparatus based on a low-frequency hollow cathode according to claim 1, characterized in that: The reaction gas supply system includes a reaction gas delivery pipe, a mass flow controller, and a normally closed valve. The input end of the reaction gas delivery pipe is connected to a reaction gas cylinder, and the output end of the reaction gas delivery pipe is connected to the reaction gas inlet on the hollow cathode module. The mass flow controller and the normally closed valve are both located on the reaction gas delivery pipe, with the normally closed valve adjacent to the output end of the reaction gas delivery pipe. The reaction gas cylinder is selected from oxygen cylinders, nitrogen cylinders, ammonia cylinders, hydrogen cylinders, or inert gas cylinders.

7. The plasma atomic layer deposition apparatus based on a low-frequency hollow cathode according to claim 1, characterized in that: The precursor supply system includes a precursor delivery pipe and an ALD valve installed on the precursor delivery pipe. The input end of the precursor delivery pipe is a precursor gas inlet, and the output end of the precursor delivery pipe is connected to the precursor gas inlet on the reaction chamber.

8. The plasma atomic layer deposition apparatus based on a low-frequency hollow cathode according to claim 1, characterized in that: The exhaust system includes an exhaust pipe, a butterfly valve and an angle valve installed on the exhaust pipe, and a vacuum pump connected to the exhaust pipe outlet. The exhaust pipe inlet is connected to the reaction chamber and communicates with the interior of the reaction chamber.

9. A deposition method based on the plasma atomic layer deposition apparatus of claim 1, characterized in that: Specifically, it includes the following steps: (1) Turn on the precursor supply system and heating plate. Set the heating temperature of the heating plate to 100℃~450℃. The precursor gas enters the reaction chamber and is adsorbed on the surface of the heated deposition substrate. (2) After the precursor adsorption is completed, the unadsorbed precursor gas is discharged using the exhaust system. Then, the pressure in the hollow cavity of the hollow cathode module is adjusted using the exhaust system, and the exhaust system is then closed. (3) Turn on the reaction gas supply system and the low frequency power supply. The reaction gas flows into the hollow cavity of the hollow cathode module and enters the hollow cathode tube through the hole on the hollow cathode tube. The low frequency power supply drives the hollow cathode tube to generate electrons. The electrons collide with the reaction gas to form a plasma of the reaction gas. The plasma of the reaction gas diffuses out through the hole on the hollow cathode tube and diffuses into the reaction cavity through the reaction gas inlet at the bottom of the hollow cavity. The plasma of the reaction gas reacts with the precursor adsorbed on the surface of the deposition substrate to form an atomic layer. (4) After the reaction is complete, the reaction byproducts can be discharged using the exhaust system.

10. The deposition method according to claim 9, characterized in that: The exhaust system adjusts the pressure inside the hollow cavity of the hollow cathode module to 0.01 to 10 Torr. The distance between the bottom end of the hollow cathode tube and the top end of the deposition substrate is adjusted according to the pressure inside the hollow cavity and decreases as the pressure inside the hollow cavity increases.

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