Atomic layer deposition method and thin film prepared by atomic layer deposition method

Abstract

The invention belongs to the field of thin films, and particularly discloses an atomic layer deposition method and a thin film prepared through the atomic layer deposition method. According to the deposition method, the reaction cavity, the two input pipeline systems, the outlet valve and the vacuum pump in the atomic layer deposition system are used for controlling precursor pulse deposition and inert gas purging conditions in the atomic deposition process, and the film deposition state is improved; the efficiency of purging and removing substances and impurity residues such as a precursor and a reaction product thereof is improved, the problem that the quality of a deposited film is affected by the impurity residues in a reaction system or on the surface of a sample in the film deposition process is avoided, the uniformity and compactness of film deposition and the coverage rate and conformal rate of a film on the surface of a base material hole are improved, the defects of the film are reduced, and the yield is improved. And the method can be applied to a substrate with a high aspect ratio structure to deposit the film, so that the purpose of manufacturing a large-size complicated special-shaped structure device is achieved.

Description

Technical Field

[0001] This invention belongs to the field of thin films, specifically relating to an atomic layer deposition method and the thin films obtained therefrom. Background Technology

[0002] Atomic layer deposition (ALD) is a chemical reaction-based thin film deposition technique. Its basic principle is to deposit thin films layer by layer by utilizing the chemical reaction of a gaseous precursor on a substrate surface. Specifically, the basic ALD process includes four steps: a first precursor pulse, purging, a second precursor pulse, and purging, repeated cyclically until the desired film thickness is achieved. ALD technology features a layer-by-layer saturation reaction characteristic; this surface reaction is self-limiting, allowing for precise control of the target film thickness and the acquisition of highly dense films.

[0003] In the field of integrated circuits, aspect ratio is defined as the ratio of etching depth to the critical dimension (CD). With the continuous reduction in feature size of high-density integrated circuits, uniform and void-free filling deposition processes for high aspect ratio gaps are crucial. Traditional thin film deposition techniques such as evaporation, sputtering, and chemical vapor deposition (CVD) face numerous challenges in fabricating high aspect ratio structures, including uneven deposition, porosity, and surface layer defects, making it difficult to meet the manufacturing requirements of high aspect ratio devices. ALD technology, due to its layer-by-layer saturation reaction characteristics, controllable deposition parameters, and excellent deposition uniformity, exhibits irreplaceable advantages in the fabrication of high aspect ratio devices. However, in the deposition of thin films on high aspect ratio materials, especially on substrates with irregular or non-uniform porous structures, ALD technology suffers from defects such as low and uneven coverage of the sidewalls or steps of the substrate's pores, resulting in incomplete deposited films with poor conformability. Furthermore, due to the uneven and incomplete deposition of thin films on substrates with irregular or non-uniform pore structures, and the high probability of pore blockage caused by residual particulate impurities during the deposition process, the performance and application of the deposited thin film are affected, resulting in a decrease in product qualification rate and an increase in production costs.

[0004] Therefore, improving the thin film preparation quality of ALD on high aspect ratio structural materials has become a challenging technical problem in order to further improve the performance of high aspect ratio device manufacturing. Summary of the Invention

[0005] In view of the problems of uneven, incomplete and easily clogged films obtained by depositing thin films on porous materials using ALD technology, the present invention will provide an atomic layer deposition method and the thin film obtained therefrom.

[0006] To achieve the above objectives, the following technical solutions are specifically included: On the one hand, the present invention provides an atomic layer deposition method, which uses an atomic layer deposition system to perform atomic layer deposition; The atomic layer deposition system includes a reaction chamber, an air inlet and an air outlet disposed on the reaction chamber. The air inlet is provided with a first input pipeline system and a second input pipeline system connected to the air inlet. The air outlet is provided with an outlet valve and an output pipeline system connected to the air outlet. The output pipeline system includes a vacuum pump. The first input pipeline system includes a first inert gas branch pipeline and a first precursor source branch pipeline. One end of the first inert gas branch pipeline is connected to an inert gas, and one end of the first precursor source branch pipeline is connected to a first precursor. The second input pipeline system includes a second inert gas branch pipeline and a second precursor source branch pipeline; one end of the second inert gas branch pipeline is connected to an inert gas, and one end of the second precursor source branch pipeline is connected to a second precursor. The atomic layer deposition process specifically includes the following steps: S1. Sample pretreatment: Pretreatment of the sample substrate to be deposited; S2, First precursor deposition: The pretreated sample substrate to be deposited is placed in the reaction chamber, the outlet valve is closed, the first precursor is introduced into the reaction chamber through the first input pipeline system and deposited on the sample substrate. After the reaction is completed, the introduction of the first precursor is stopped. S3. Purging: Open the outlet valve and purge the reaction chamber with inert gas through the first input pipeline system until the gas pressure in the reaction chamber is P1; then close the outlet valve and stop the inert gas supply. Use a vacuum pump to evacuate the reaction chamber until the gas pressure in the reaction chamber is P2. After the evacuation is completed, stop the inert gas supply; P1 is greater than P2. S4. Second precursor deposition: The second precursor is introduced into the reaction chamber through the second input pipeline system and deposited on the sample substrate. After the reaction is completed, the introduction of the second precursor is stopped. S5. Purging: Open the outlet valve and purge the reaction chamber with inert gas through the second input pipeline system until the gas pressure in the reaction chamber is P3; then close the outlet valve and stop the inert gas supply. Use a vacuum pump to evacuate the reaction chamber until the gas pressure in the reaction chamber is P4. After the evacuation is completed, stop the inert gas supply; P3 is greater than P4. S6. Repeat steps S2-S5 above to obtain a thin film on the sample substrate surface.

[0007] In the deposition method of this invention, the reaction chamber, two input pipeline systems, an outlet valve, and a vacuum pump in the atomic layer deposition system are used to control the precursor pulse deposition and inert gas purging conditions during the atomic deposition process. This improves the state of the thin film deposition, increases the efficiency of purging to remove impurities such as precursors and reaction products, and avoids the quality of the deposited thin film being affected by impurities on the reaction system or sample surface. It also improves the uniformity, density, coverage of substrate pores, and conformability of the deposited thin film, reduces film defects, and prevents substrate pore blockage caused by film inhomogeneity or impurities. This method is more suitable for deposition on substrates with high aspect ratio structures, enabling the fabrication of large-size, complex, irregularly shaped devices. Specifically, during the precursor pulse stage, the outlet valve is closed to allow the precursor to fully penetrate into the microporous structure. During the purging stage, the pressure in the reaction chamber is constantly changed (by switching between pressures P1 and P2 or between pressures P3 and P4) to remove the residual precursor and byproducts in the pores in a timely manner, so as to avoid affecting the next half-reaction. At the same time, it avoids the discontinuity of the film caused by some small particles remaining in the reaction and avoids pore blockage.

[0008] The atomic deposition method of the present invention includes, but is not limited to, the preparation of oxide films including Al2O3, TiO2, HfO2, ZrO2, SiO2, SnO2, etc. Precursor A and precursor B are used to distinguish the two precursors for preparing the film. Precursor A corresponding to the aforementioned oxide films includes halides and organometallic compounds, namely TMA (trimethylaluminum), TiCl4, TDMAHf / TEMAHf (tetra(dimethylamino)hafnium / tetra(ethylmethylamino)hafnium), TDMAZr / TEMAZr (tetra(dimethylamino)zirconium / tetra(ethylmethylamino)zirconium), DBEASi (di-tert-butoxysilane), and TDMASn (tetra(dimethylamino)tin). Precursor B commonly used is H2O, O3, O2, etc. Nitrides such as AlN and TiN can also be prepared, with corresponding precursor A being TMA and TiCl4, and precursor B generally being NH3.

[0009] Preferably, the first input pipeline system further includes a first main pipeline, wherein the first inert gas branch pipeline and the first precursor source branch pipeline intersect and converge before the air inlet to form the first main pipeline.

[0010] Preferably, the second input pipeline system further includes a second main pipeline, wherein the second inert gas branch pipeline and the second precursor source branch pipeline intersect and converge before the air inlet to form the second main pipeline.

[0011] In the first and second input pipeline systems, one end of the main pipeline is directly connected to the air inlet of the reaction chamber, and the other end is connected to the precursors of two branches. One branch is connected to inert gas, and the other branch is connected to the precursor. The fluid is switched by valves installed on the pipeline, which effectively improves the efficiency of gas delivery and reduces the laying of pipelines.

[0012] Preferably, in the atomic layer deposition system, the outlet valve includes at least one of an angle valve and a butterfly valve; when the butterfly valve is open, its opening degree is 10°-90°, and when the butterfly valve is closed, its opening degree is 0°. The reaction between the two precursors (precursor A and precursor B) is rapid, requiring a fast valve response to meet the reaction time requirements and achieve efficient deposition. By changing its opening degree, the butterfly valve can better regulate the gas pressure in the pipeline and the pressure in the reaction chamber, resulting in more efficient and stable film deposition and a longer equipment lifespan.

[0013] Preferably, the first inert gas branch pipeline, along the direction of gas entering the reaction chamber, includes, in sequence, a first flow meter, a first pipeline pressure gauge, and a first pneumatic valve.

[0014] Preferably, the first precursor source branch pipeline, along the direction of gas inflow into the reaction chamber, sequentially includes a precursor A source bottle, a precursor A source bottle manual valve, a second pneumatic valve, and a third pneumatic valve. The precursor A and inert gas are switched by controlling the first to third pneumatic valves.

[0015] Preferably, the second inert gas branch pipeline, along the direction of gas entering the reaction chamber, includes, in sequence, a second flow meter, a second pipeline pressure gauge, and a fourth pneumatic valve.

[0016] Preferably, the second precursor source branch pipeline, along the direction of gas inflow into the reaction chamber, sequentially includes a precursor B source bottle, a precursor B source bottle manual valve, a fifth pneumatic valve, and a sixth pneumatic valve. Precursor B and inert gas are switched by controlling the fourth to sixth pneumatic valves.

[0017] More preferably, the temperatures of the precursor A source bottle and the precursor B source bottle are independently selected from 20-300℃.

[0018] Preferably, in step S1, the pretreatment includes washing and drying.

[0019] Preferably, in step S1, the sample substrate to be deposited has a porous structure.

[0020] Preferably, in step S1, the substrate material of the sample to be deposited includes at least one of metals (e.g., aluminum) and oxides (alumina, silicon oxide, etc.).

[0021] More preferably, the hole structure includes an irregularly shaped hole structure, wherein the upper and lower hole diameters of the irregularly shaped hole structure are not the same, and the hole centers are not on the same vertical line. The upper hole diameter is 1-3 mm, and the lower hole diameter is 0.05-1 mm; the depth-to-width ratio of the hole structure is (20-50):1. This structure is mainly used in semiconductor showerheads for CVD processes. By utilizing the change in hole diameter size of this type of structure, the airflow velocity through the hole is buffered, and the airflow distribution is made more uniform. Due to the characteristics of this irregular structure, existing technologies often encounter problems such as pore blockage, uneven film formation, or no film formation when depositing thin films on its surface. The deposition method of this invention can set different valve actions during the precursor pulse and purging stages to improve the process results. In particular, during the precursor pulse stage, the outlet valve is closed to allow the precursor to fully penetrate into the microporous structure. During the purging stage, pressure changes in the reaction chamber (switching between pressures P1 and P2 or between pressures P3 and P4) promptly remove residual precursors and byproducts from the pores, avoiding their impact on the next half-reaction. This also prevents the film from becoming discontinuous due to residual microparticles and avoids pore blockage.

[0022] Preferably, in steps S2 and S4, the deposition reaction time is independently selected from 1-10 s; and the deposition reaction temperature is independently selected from 100-300 °C.

[0023] Preferably, the deposition reaction is repeated two or more times in accordance with step S2. More specifically, the deposition reaction is repeated 2 to 10 times in accordance with step S2, the time of each deposition reaction is independently selected from 1 to 10 seconds, and the temperature of each deposition reaction is independently selected from 100 to 300°C.

[0024] Preferably, in step S2, when the first precursor is introduced into the reaction chamber, the temperature of the first precursor source branch pipe in the atomic layer deposition system is 50-200°C.

[0025] Preferably, the deposition reaction is repeated two or more times in the manner of step S4. More specifically, the deposition reaction is repeated 2 to 10 times in the manner of step S4, with the time of each deposition reaction independently selected from 1 to 10 seconds and the temperature of each deposition reaction independently selected from 100 to 300°C.

[0026] Preferably, in steps S3 and S5, P1 and P3 are each independently selected from 5-20 torr, P2 and P4 are each independently selected from 0.1-3 torr, and the flow rate of the inert gas is 5-2000 sccm.

[0027] Preferably, the purging is performed twice or more in accordance with step S3. More specifically, the purging is performed 2 to 10 times in accordance with step S3. During each purging, P1 is independently selected from 5 to 20 torr and P2 is independently selected from 0.1 to 3 torr.

[0028] Preferably, in step S4, when the second precursor is introduced into the reaction chamber, the temperature of the second precursor source branch pipe in the atomic layer deposition system is 50-200°C.

[0029] Preferably, the purging is performed twice or more in accordance with step S5. More specifically, the purging is performed 2 to 10 times in accordance with step S5. During each purging, P3 is independently selected from 5 to 20 torr and P4 is independently selected from 0.1 to 3 torr.

[0030] In the deposition method of this invention, multiple purging and deposition cycles are preferably performed in combination. This allows for more precise control of film thickness and enables the deposition of more uniform films with high step coverage on the sample substrate surface. Regardless of the shape and size of the sample substrate, uniform film coverage can be obtained. Specifically, the film thickness deposited on the top, sides, and bottom of the device sample pattern is essentially the same. This method can prepare films with good sidewall and step coverage and good conformal properties in large-sized samples with irregular pores. This characteristic is crucial for protecting sensitive areas and maintaining structural integrity, and is key to forming surface deposition film coverage for high aspect ratio and 3D structures, such as gate insulating layers and nanowire encapsulation in semiconductor manufacturing, all of which require specific film deposition techniques. Furthermore, the combination of multiple purging and deposition cycles effectively fills the grooves and pores on the substrate surface, resulting in a void-free film that avoids the formation of voids or gaps, thereby achieving tight encapsulation and good durability. Furthermore, the deposition method of the present invention has wide applicability and is suitable for substrates of various shapes and materials. It can form films uniformly over large areas and is particularly suitable for preparing thin films with high aspect ratios, such as 3D NAND and other devices with complex structures, microelectromechanical systems (MEMS), sensors and biochips. This makes it have broad application prospects and important research value in the fields of nanoelectronics, nano-optics, sensor manufacturing and materials science.

[0031] On the other hand, the present invention provides a thin film prepared by the atomic layer deposition method described above.

[0032] Preferably, the thickness of the film is 1-500 nm, and more preferably 10-50 nm.

[0033] Compared with the prior art, the present invention has the following beneficial effects: In the deposition method of the present invention, the reaction chamber, two input pipeline systems, outlet valve and vacuum pump in the atomic layer deposition system are used to control the precursor pulse deposition and inert gas purging conditions in the atomic deposition process, improve the state of film deposition, improve the efficiency of purging to remove precursors and their reaction products and other substances and impurities, avoid the quality of the deposited film affected by impurities in the reaction system or sample surface, improve the uniformity, density, coverage of the film on the surface of substrate pores and conformability of film deposition, reduce film defects, avoid the blockage of substrate pores caused by film inhomogeneity or impurities, and are more conducive to its application on substrates with high aspect ratio structures to deposit films, so as to achieve the purpose of manufacturing large-size complex irregular structure devices. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of an atomic layer deposition system. Figure 2 This is a schematic diagram of the irregular-shaped hole structure of the sample in Example 1; Reference numerals: 100-Reaction chamber, 200-Inlet, 300-Outlet, 301-Outlet valve, 400-Output piping system, 401-Vacuum pump, 500-First input piping system, 501-First main pipeline, 502-First inert gas branch pipeline, 503-First flow meter, 504-First pipeline pressure gauge, 505-First pneumatic valve, 506-First precursor source branch pipeline, 507-Precursor A source bottle, 508-Precursor 509 - Second pneumatic valve for source bottle A; 510 - Third pneumatic valve; 600 - Second input pipeline system; 601 - Second main pipeline; 602 - Second inert gas branch pipeline; 603 - Second flow meter; 604 - Second pipeline pressure gauge; 605 - Fourth pneumatic valve; 606 - Second precursor source branch pipeline; 607 - Precursor B source bottle; 608 - Precursor B source bottle hand valve; 609 - Fifth pneumatic valve; 610 - Sixth pneumatic valve. Detailed Implementation

[0035] To better illustrate the purpose, technical solution, and advantages of this invention, specific embodiments will be used to further explain the invention below. Unless otherwise specified, the test methods used in the embodiments and / or comparative examples are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available.

[0036] A schematic diagram of an atomic layer deposition system is shown below. Figure 1As shown, the system includes a reaction chamber 100, an inlet 200 on the reaction chamber, and an outlet 300 on the reaction chamber 100. The outlet 300 is equipped with an outlet valve 301 and an output piping system 400. The outlet valve 301 controls the gas inlet and outlet; the output piping system 400 is equipped with a vacuum pump 401 that provides the power for evacuation. The outlet valve 301 is a component that connects (through piping) the vacuum pump 401 to the reaction chamber 100, so that the reaction chamber 100 and the vacuum piping are in a state of communication when the reaction chamber 100 is evacuated, and prevents the vacuum pump 401 from evacuating the reaction chamber 100 when the vacuum is broken. The outlet valve 301 includes two types: angle valve and butterfly valve, which are labeled 301-a and 301-b for easy distinction. The valve body of the angle valve 301-a is at a right angle, and its valve core (such as a piston or valve stem) usually moves in a straight line to open or close the flow channel; the butterfly valve 301-b controls the partial opening (0° < rotation angle < 90°), full opening (rotation angle 90°), and closing (rotation angle 0°) of the flow channel and the flow rate by rotating the disc (butterfly plate) at different angles within the range of 0-90°.

[0037] The air inlet 200 is equipped with a first input pipeline system 500 and a second input pipeline system 600. Each pipeline system has a main pipeline and two parallel branch pipelines. The two branch pipelines converge to form the main pipeline before reaching the air inlet 200. The two branch pipelines are used to input inert gas and precursor, respectively, and are therefore designated as the inert gas branch pipeline and the precursor source branch pipeline. Valves installed on the branch pipelines switch their opening and closing. A flow meter and a pressure gauge are installed on the inert gas branch pipeline to control the gas flow rate and pressure.

[0038] Specifically, the first input pipeline system 500 includes a first main pipeline 501, a first inert gas branch pipeline 502, and a first precursor source branch pipeline 506. Along the direction of gas flow into the reaction chamber 100, one end of the first inert gas branch pipeline 502 of the first input pipeline system 500 inputs inert gas, and the other end is connected to the first main pipeline 501. The first main pipeline 501 is connected to the air inlet 200, allowing inert gas to be input into the reaction chamber 100. Along the direction of gas flow into the reaction chamber 100, the first inert gas branch pipeline 502 sequentially includes a first flow meter 503, a first pipeline pressure gauge 504, and a first pneumatic valve 505. Along the direction of gas flow into the reaction chamber 100, the first precursor source branch pipeline 506 sequentially includes a precursor A source bottle 507, a precursor A source bottle hand valve 508, a second pneumatic valve 509 (safety valve), and a third pneumatic valve 510. The first inert gas branch pipeline 502 and the first precursor source branch pipeline 506 on the first input pipeline system 500 intersect at the section after the first pneumatic valve 505 and the third pneumatic valve 510 and before the air inlet 200, and converge to form the first main pipeline 501.

[0039] Specifically, the second input pipeline system 600 includes a second main pipeline 601, a second inert gas branch pipeline 602, and a second precursor source branch pipeline 606. Along the direction of gas flow into the reaction chamber 100, one end of the second inert gas branch pipeline 602 of the second input pipeline system 600 inputs inert gas, and the other end is connected to the second main pipeline 601. The second main pipeline 601 is connected to the inlet 200, allowing inert gas to be input into the reaction chamber 100. Along the direction of gas flow into the reaction chamber 100, the second inert gas branch pipeline 602 sequentially includes a second flow meter 603, a second pipeline pressure gauge 604, and a fourth pneumatic valve 605. Along the direction of gas flow into the reaction chamber 100, the second precursor source branch pipeline 606 sequentially includes a precursor B source bottle 607, a precursor B source bottle hand valve 608, a fifth pneumatic valve 609, and a sixth pneumatic valve 610. The second inert gas branch pipeline 602 and the second precursor source branch pipeline 606 on the second input pipeline system 600 intersect after the fourth pneumatic valve 605 and the sixth pneumatic valve 610 and before the air inlet 200, and converge to form the second main pipeline 601.

[0040] Example 1 An atomic layer deposition method includes the following steps: S1. Sample Pretreatment: Take the sample substrate to be deposited. The sample substrate is aluminum and has irregularly shaped pores (through holes). The schematic diagram of its pore structure is shown in the figure. Figure 2As shown, the upper and lower diameters of the holes are inconsistent, and the centers of the holes are not on the same vertical line. The diameter of the upper hole is 2 mm, and the diameter of the lower hole is 0.6 mm. The ratio of the depth of the sample hole to the diameter of the lower hole is defined as the depth-to-width ratio. In this embodiment, the depth-to-width ratio of the sample substrate is 30:1. The sample is cleaned and dried in an oven or treated with an air knife to remove impurities such as particles and moisture remaining on the surface and inside the holes.

[0041] S2. Equipment preparation before deposition: using... Figure 1 The atomic layer deposition system shown performs atomic deposition, placing a sample with irregularly shaped pores as the deposition substrate in the reaction chamber 100. The temperatures of the reaction chamber 100, the precursor source bottle, and the precursor piping sections are set accordingly. The temperature of the reaction chamber 100 is 200°C. Trimethylaluminum (MA) and H₂O are used as precursor sources in precursor source bottle A 507 and precursor source bottle B 607, respectively. The temperature of precursor source bottle A 507 is set to 35°C, and the temperature of precursor source bottle B 607 is set to 30°C. The temperatures of the first inert gas branch pipe 502, the second inert gas branch pipe 602, the first precursor source branch pipe 506, and the second precursor source branch pipe 606 are all set to 80°C. In this embodiment, the inert gas is N₂.

[0042] S3, Thin Film Deposition: S3-1. Perform precursor A (TMA) pulse: Close angle valve 301-a, open precursor A source bottle hand valve 508, open second pneumatic valve 509 and third pneumatic valve 510 to allow precursor A (TMA) gas to enter reaction chamber 100, and set the opening time of third pneumatic valve 510 to 3s, that is, the precursor A pulse deposition time is 3s, so that precursor A is deposited on the sample (including the inner surface of the pore); close third pneumatic valve 510 to stop the introduction of precursor A.

[0043] S3-2. Perform precursor A purging: In this stage, to ensure that all reaction byproducts and unreacted precursors on the sample are completely purged, cyclic purging is performed by opening and closing the valve. The specific operation is as follows: Open angle valve 301-a and set its opening time to 5 seconds. Simultaneously, open the first pneumatic valve 505 on the first inert gas branch line 502 and set the flow rate on the first flow meter 503 to 1000 sccm. Introduce nitrogen gas as a purging gas through the first input pipeline system 500 and into the reaction chamber 100, bringing the pressure inside the reaction chamber 100 to 15 torr. Close angle valve 301-a and set its closing time to 15 seconds. Close the first pneumatic valve 505 on the first inert gas branch line 502 to stop the nitrogen supply. Start the vacuum pump 401 to evacuate the reaction chamber 100 to 1 torr. The above process of introducing nitrogen gas for purging and evacuating is considered one cycle. Perform five cycles of purging according to the above steps. After the cycle is completed, close the first pneumatic valve 505 to stop the nitrogen supply.

[0044] S3-3, Precursor B (H2O) Pulse: Open the manual valve 608 of the precursor B source bottle, close the angle valve 301-a, and open the fifth pneumatic valve 609 and the sixth pneumatic valve 610, so that the precursor B (H2O) enters the reaction chamber 100 and is deposited on the sample surface, so that the precursor B (H2O) reacts with the precursor A (TMA) deposited on the sample surface to generate an alumina film. The opening time of the sixth pneumatic valve 610 is set to 2s, that is, the pulse time of the precursor B (H2O) is 2s. After the pulse ends, the sixth pneumatic valve 610 is closed to stop the introduction of precursor B (H2O).

[0045] S3-4, Precursor B (H2O) Purging: In this stage, to ensure that all reaction byproducts and unreacted precursors on the sample are completely purged, cyclic purging is performed by opening and closing the valve. The specific operation is as follows: Open angle valve 301-a and set its opening time to 5 seconds. Simultaneously, open the fourth pneumatic valve 605 on the second inert gas branch line 602 and set the flow rate on the second flow meter 603 to 1300 sccm. Introduce nitrogen gas as a purging gas through the second input pipeline system 600 and into the reaction chamber 100, bringing the pressure inside the reaction chamber 100 to 20 torr. Close angle valve 301-a and set its closing time to 15 seconds. Close the fourth pneumatic valve 605 on the second inert gas branch line 602 to stop the nitrogen supply. Start the vacuum pump 401 to evacuate the reaction chamber 100 to 1.5 torr. The above nitrogen purging and evacuation process is considered one cycle of purging. Perform five cycles of purging according to the above steps. After the cycle is completed, close the fourth pneumatic valve 605 to stop the nitrogen supply.

[0046] S4. Cyclic deposition: Consider step S3 above as a cyclic deposition. Perform 3 cyclic depositions according to the above operation steps. After the cycle is completed, open angle valve 301-a and close all pneumatic valves to obtain a product containing an alumina film.

[0047] Example 2 Compared with Example 1, this embodiment replaces angle valve 301-a with butterfly valve 301-b. The opening degree of this butterfly valve is 0~90°. When the butterfly valve is at 0°, it is closed; when it is greater than 0°, it is partially or fully open. The rest are the same. Specifically, the steps are as follows: S1. Sample Pretreatment: Take the sample substrate to be deposited. The sample substrate is aluminum and has irregularly shaped pores (through holes). The schematic diagram of its pore structure is shown in the figure. Figure 2 As shown, the upper and lower diameters of the holes are inconsistent, and the centers of the holes are not on the same vertical line. The diameter of the upper hole is 2 mm, and the diameter of the lower hole is 0.6 mm. The ratio of the depth of the sample hole to the diameter of the lower hole is defined as the depth-to-width ratio. In this embodiment, the depth-to-width ratio of the sample substrate is 30:1. The sample is cleaned and dried in an oven or treated with an air knife to remove impurities such as particles and moisture remaining on the surface and inside the holes.

[0048] S2. Equipment preparation before deposition: using... Figure 1 The atomic layer deposition system shown performs atomic deposition, placing a sample with irregularly shaped pores as the deposition substrate in the reaction chamber 100. The temperatures of the reaction chamber 100, the precursor source bottle, and the precursor piping sections are set as follows: the temperature of the reaction chamber 100 is 200°C; the precursor source bottles A and B are respectively set with trimethylaluminum (MA) and H₂O as precursor sources; the temperature of precursor source bottle A is set to 35°C; the temperature of precursor source bottle B is set to 30°C; and the temperatures of the first inert gas branch pipe 502, the second inert gas branch pipe 602, the first precursor source branch pipe 506, and the second precursor source branch pipe 606 are all set to 80°C. In this embodiment, the inert gas is N₂.

[0049] S3, Thin Film Deposition: S3-1, Precursor A (TMA) Pulse: Set butterfly valve 301-b to 0° closed state, open precursor A source bottle hand valve 508, open second pneumatic valve 509 and third pneumatic valve 510 to allow precursor A (TMA) gas to enter reaction chamber 100, and set the opening time of third pneumatic valve 510 to 3s, that is, the precursor A pulse time is 3s, so that precursor A is deposited on the sample (including the inner surface of the pores); close third pneumatic valve 510 to stop the introduction of precursor A.

[0050] S3-2. Perform precursor A purging: In this stage, to ensure that all reaction byproducts and unreacted precursors on the sample are completely purged, cyclic purging is performed by opening and closing the valve. The specific operation is as follows: Set butterfly valve 301-b to the 90° open position and set its opening time to 5 seconds. Simultaneously, open the first pneumatic valve 505 on the first inert gas branch line 502 and set the flow rate on the first flow meter 503 to 1000 sccm. Introduce nitrogen gas as a purging gas through the first input pipeline system 500 and into the reaction chamber 100, bringing the pressure inside the reaction chamber 100 to 15 torr. Close butterfly valve 301-b (set to 0°) and set its closing time to 15 seconds. Close the first pneumatic valve 505 on the first inert gas branch line 502 to stop the nitrogen supply. Start vacuum pump 401 to evacuate the reaction chamber 100 to 1 torr. The above nitrogen purging and evacuation process is considered one cycle. Perform five cycles of purging according to the above steps. After the cycle, close the first pneumatic valve 505 to stop the nitrogen supply.

[0051] S3-3, Precursor B (H2O) Pulse: Open the manual valve 608 of the precursor B source bottle, close the butterfly valve 301-b (set to 0°), open the fifth pneumatic valve 609 and the sixth pneumatic valve 610, so that the precursor B (H2O) enters the reaction chamber 100 and is deposited on the sample surface, so that the precursor B (H2O) reacts with the precursor A (TMA) deposited on the sample surface to generate an alumina film. The opening time of the sixth pneumatic valve 610 is set to 2s, that is, the pulse time of the precursor B (H2O) is 2s. After the pulse ends, close the sixth pneumatic valve 610 to stop the introduction of precursor B (H2O).

[0052] S3-4, Precursor B (H2O) Purging: In this stage, to ensure that all reaction byproducts and unreacted precursors on the sample are completely purged, cyclic purging is performed by opening and closing the valve. The specific operation is as follows: Open butterfly valve 301-b (set to 90°), and set the opening time of butterfly valve 301-b to 5 seconds; simultaneously open the fourth pneumatic valve 605 on the second inert gas branch line 602, and set the flow rate on the second flow meter 603 to 1300 sccm. Introduce nitrogen gas as purging gas through the second input pipeline system 600 and into the reaction chamber 100, so that the pressure inside the reaction chamber 100 reaches 20 torr. Close butterfly valve 301-b (set to 0°), set the closing time of butterfly valve 301-b to 15 seconds, and close the fourth pneumatic valve 605 on the second inert gas branch line 602 to stop the nitrogen supply; start vacuum pump 401 to evacuate the inside of the reaction chamber 100 to 1.5 torr. The above process of introducing nitrogen gas for purging and evacuating the vacuum is considered as one cycle of purging. Perform a total of 5 cycles of purging according to the above operating steps. After the cycle is completed, close the fourth pneumatic valve 605 to stop the nitrogen supply.

[0053] S4. Cyclic deposition: Treat step S3 as a cyclic deposition and perform 3 cyclic depositions according to the above operation steps. After the cycle is completed, open butterfly valve 301-b (set to 90°) and close all pneumatic valves to obtain a product containing an alumina film.

[0054] Example 3 The difference between this embodiment and embodiment 2 lies in steps S3-2 and S3-4; the rest are the same. Specifically, steps S3-2 and S3-4 in this embodiment are as follows: S3-2. Precursor A Purging: In this stage, to ensure that all reaction byproducts and unreacted precursors on the sample are completely purged, cyclic purging is performed by opening and closing valves. The specific operation is as follows: Set butterfly valve 301-b to the 75° open position and set the opening time of butterfly valve 301-b to 5s; simultaneously open the first pneumatic valve 505 on the first inert gas branch pipeline 502 and set the flow rate on the first flow meter 503 to 700sccm. Introduce nitrogen gas as purging gas through the first input pipeline system 500 and into the reaction chamber 100, so that the pressure inside the reaction chamber 100 reaches 13 torr. Set the opening degree of butterfly valve 301-b to 10° and maintain this opening degree for 15s. Close the first pneumatic valve 505 on the first inert gas branch pipeline 502 to stop the introduction of nitrogen gas; start vacuum pump 401 to evacuate the inside of the reaction chamber 100 to 2.5 torr. The process of introducing nitrogen gas for purging and vacuuming is considered as one cycle. The above operation steps are followed for a total of 5 cycles of purging. After the cycle is completed, the first pneumatic valve 505 is closed to stop the introduction of nitrogen gas.

[0055] S3-4, Precursor B (H2O) Purging: In this stage, to ensure that all reaction byproducts and unreacted precursors on the sample are completely purged, cyclic purging is performed by opening and closing valves. The specific operation is as follows: Set butterfly valve 301-b to the 75° open position and set the opening time of butterfly valve 301-b to 5s; simultaneously open the fourth pneumatic valve 605 on the second inert gas branch line 602 and set the flow rate on the second flow meter 603 to 1100sccm. Nitrogen gas is introduced through the second input pipeline system 600 as the purging gas and enters the reaction chamber 100, so that the pressure inside the reaction chamber 100 reaches 17 torr. Set the opening degree of butterfly valve 301-b to 10° and maintain this opening degree for 15s. Close the fourth pneumatic valve 605 on the second inert gas branch line 602 to stop the introduction of nitrogen gas; simultaneously start the vacuum pump 401 to evacuate the inside of the reaction chamber 100 to 3.5 torr. The process of introducing nitrogen gas for purging and vacuuming is defined as one cycle of purging. A total of 5 cycles of purging are performed according to the above operating steps. After the cycle is completed, the fourth pneumatic valve 605 is closed to stop the introduction of nitrogen gas.

[0056] Example 4 Compared with Example 2, the difference in this embodiment is that the number of cyclic purgings in steps S3-2 and S3-4 is changed from 5 times to 1 time, while the rest are the same.

[0057] Example 5 Compared with Example 2, the difference in this embodiment is that the number of cyclic purgings in steps S3-2 and S3-4 is changed from 5 times to 10 times, while the rest are the same.

[0058] Example 6 The difference between this embodiment and embodiment 2 lies in steps S3-1 and S3-3; the rest are the same. Specifically, steps S3-1 and S3-3 in this embodiment are as follows: S3-1, Precursor A (TMA) stepped program pulse: Set butterfly valve 301-b to 0° closed state, and open precursor A source bottle hand valve 508.

[0059] The second pneumatic valve 509 and the third pneumatic valve 510 are opened to allow gas of precursor A (TMA) to enter the reaction chamber 100. The opening time of the third pneumatic valve 510 is set to 0.5s, meaning the precursor A pulse time is 0.5s, allowing precursor A to deposit on the sample (including the inner surface of the pores). Then, the second pneumatic valve 509 and the third pneumatic valve 510 are closed for 1.5s to stop the flow of precursor A. The above process of controlling the opening and closing of the second pneumatic valve 509 and the third pneumatic valve 510 completes one cycle of precursor A pulses. This cycle is repeated for a total of 5 cycles.

[0060] S3-3, Precursor B (H2O) stepped program pulse: Open the manual valve 608 of the precursor B source bottle and close the butterfly valve 301-b (set to 0°).

[0061] The fifth pneumatic valve 609 and the sixth pneumatic valve 610 are opened, with an opening time set to 0.3 s, allowing precursor B (H2O) to enter the reaction chamber 100 and deposit on the sample surface. Precursor B (H2O) reacts with the precursor A (TMA) deposited on the sample surface to generate an alumina film; the precursor B (H2O) pulse duration is 0.3 s. Then, the fifth pneumatic valve 609 and the sixth pneumatic valve 610 are closed, stopping the flow of precursor B (H2O), with a closing time set to 1.5 s. This process of controlling the opening and closing of the fifth pneumatic valve 609 and the sixth pneumatic valve 610 completes one cycle of the precursor B pulse. This cycle is repeated for a total of 6 cycles.

[0062] Comparative Example 1 This comparative example uses a conventional deposition method, specifically including the following steps: S1. Sample Pretreatment: Take the sample substrate to be deposited. The sample substrate is aluminum and has irregularly shaped pores (through holes). The schematic diagram of its pore structure is shown in the figure. Figure 2 As shown, the upper and lower diameters of the holes are inconsistent, and the centers of the holes are not on the same vertical line. The diameter of the upper hole is 2 mm, and the diameter of the lower hole is 0.6 mm. The ratio of the depth of the sample hole to the diameter of the lower hole is defined as the depth-to-width ratio. In this embodiment, the depth-to-width ratio of the sample substrate is 30:1. The sample is cleaned and dried in an oven or treated with an air knife to remove impurities such as particles and moisture remaining on the surface and inside the holes.

[0063] S2. Equipment preparation before deposition: using... Figure 1 The atomic layer deposition system shown performs atomic deposition, and the angle valve remains open throughout the pulse deposition and purging processes. A sample with irregularly shaped pores is placed in the reaction chamber 100 as the deposition substrate, and the temperatures of the reaction chamber 100, the precursor source bottle, and the precursor piping sections are set accordingly. The temperature of the reaction chamber 100 is 200°C. Trimethylaluminum (MA) and H₂O are used as precursor sources in precursor source bottle A 507 and precursor source bottle B 607, respectively. The temperature of precursor source bottle A 507 is set to 35°C, and the temperature of precursor source bottle B 607 is set to 30°C. The temperatures of the first inert gas branch pipe 502, the second inert gas branch pipe 602, the first precursor source branch pipe 506, and the second precursor source branch pipe 606 are all set to 80°C. In this embodiment, the inert gas is N₂.

[0064] S3, Thin Film Deposition: S3-1. Perform precursor A (TMA) pulse: Keep the angle valve in the open position, open the precursor A source bottle hand valve 508, open the second pneumatic valve 509 and the third pneumatic valve 510 to allow the precursor A (TMA) gas to enter the reaction chamber 100, and set the opening time of the third pneumatic valve 510 to 3s, that is, the precursor A pulse time is 3s, so that the precursor A is deposited on the sample (including the inner surface of the pore); close the third pneumatic valve 510 to stop the introduction of precursor A.

[0065] S3-2. Perform precursor A purging: Keep the angle valve in the open position, open the first pneumatic valve 505 on the first inert gas branch pipeline 502 for 50 seconds, and set the flow rate on the first flow meter 503 to 1000 sccm. Introduce nitrogen gas as purging gas through the first input pipeline system 500 and purge it into the reaction chamber 100 for 50 seconds. After the purging is completed, close the first pneumatic valve 505 to stop the nitrogen gas supply.

[0066] S3-3, Precursor B (H2O) Pulse: Keep the angle valve in the open state, open the manual valve 608 of the precursor B source bottle, open the fifth pneumatic valve 609 and the sixth pneumatic valve 610, so that the precursor B (H2O) enters the reaction chamber 100 and is deposited on the sample surface, so that the precursor B (H2O) reacts with the precursor A (TMA) deposited on the sample surface to generate an alumina film. The opening time of the sixth pneumatic valve 610 is set to 2s, that is, the pulse time of the precursor B (H2O) is 2s. After the pulse ends, the sixth pneumatic valve 610 is closed to stop the introduction of precursor B (H2O).

[0067] S3-4, Precursor B (H2O) purging: Keep the angle valve in the open position, open the fourth pneumatic valve 605 on the second inert gas branch line 602, set the opening time to 40s, and set the flow rate on the second flow meter 603 to 1500sccm. Introduce nitrogen gas as purging gas through the second input pipeline system 600 and purge it into the reaction chamber 100 for 40s. After the purging is completed, close the fourth pneumatic valve 605 to stop the nitrogen gas supply.

[0068] S4. Cyclic deposition: Consider step S3 above as one cyclic deposition. Perform 3 cyclic depositions according to the above operation steps. After the cycle is completed, close all pneumatic valves to obtain a product containing an alumina film.

[0069] The above embodiments and comparative examples deposited alumina films with a target thickness of 20 nm, and evaluated the performance of the alumina films deposited on irregularly shaped samples using the following test methods.

[0070] (1) Statistics on the probability of blockage in the product: If light is seen passing through the through hole on the product when illuminated with a flashlight, the blockage has not occurred. If the light weakens or there is no light, the blockage has occurred. The percentage of the number of blocked holes to the total number of holes in each of the above embodiments and comparative examples is calculated. This percentage is the probability of blockage. The product size is 450×450mm during the test.

[0071] (2) The difference between the maximum thickness of the film at the top of the hole and the inner wall of the hole in the product: Test samples were obtained by laser cutting the holes of the product. Each test sample was 100×100mm in size. The film thickness in the test sample of the product was tested by TEM. The difference between the maximum thickness of the film at the top of the hole and the maximum thickness of the film on the inner wall of the hole was calculated. The number of test samples for each embodiment and comparative example was 10. The average value of the difference between the maximum thickness of the film at the top of the hole and the inner wall of the hole in all samples was statistically calculated.

[0072] (3) The proportion of defects such as roughness or pores on the surface of the thin film in the product: Small test samples were cut from the products obtained in the above embodiments and comparative examples to count the proportion of defects such as roughness or pores on the surface of the thin film. Each sample was 100×100mm in size, and the total number of test samples was n0=10. The roughness of each test sample was tested by a 3D surface profiler, and the number of thin film roughness Ra>0.5nm in the test samples was counted as n1. Then, the number of holes or foreign objects on the thin film of the test samples was observed by a microscope as n2. The proportion of defects was calculated as follows: (n1+n2) / n0×100%.

[0073] (4) Surface film thickness non-uniformity in the product: The film thickness at different locations in the product was measured using an ellipsometry. The formula for calculating the surface film thickness non-uniformity of the sample is: (d max -d min ) / (d max +d min ) × 100%, where d max To determine the maximum film thickness in a batch, d min To determine the minimum film thickness in a batch, calculations were performed on 10 batches, and the maximum value was taken.

[0074] The test results are shown in Table 1.

[0075] Table 1 The reaction between precursor A and precursor B is rapid, requiring a fast valve response to meet the reaction time and achieve the deposition objective. In Example 1, the angle valve used experiences reduced lifespan due to prolonged rapid opening and closing. Therefore, considering both cost and effectiveness, in Example 2, the angle valve is replaced with a butterfly valve. The gas pressure in the pipeline can be adjusted by setting the butterfly valve's opening degree, and the pressure in the reaction chamber can also be controlled by adjusting the flow meter and the butterfly valve's opening degree.

[0076] Furthermore, as can be seen from Examples 1-6 and Comparative Example 1 above, compared with traditional deposition methods, the method of the present invention can reduce the probability of pore blockage in the product to less than 10%, the difference in maximum film thickness between the top of the pore and the inner sidewall to less than 2 mm, the proportion of defects such as roughness or pores on the film surface to less than 16%, and the film thickness non-uniformity of the surface film to less than 10%. The deposition method of the present invention can effectively improve the uniformity and integrity of the film in the product, reduce the number of pores in the film, and effectively reduce the probability of pore blockage, the proportion of defects, and the difference in film thickness between the top of the pore and the inner sidewall in porous substrates.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An atomic layer deposition method, characterized in that, Atomic layer deposition was performed using an atomic layer deposition system; The atomic layer deposition system includes a reaction chamber, an air inlet and an air outlet disposed on the reaction chamber. The air inlet is provided with a first input pipeline system and a second input pipeline system connected to the air inlet. The air outlet is provided with an outlet valve and an output pipeline system connected to the air outlet. The output pipeline system includes a vacuum pump. The first input pipeline system includes a first inert gas branch pipeline and a first precursor source branch pipeline. One end of the first inert gas branch pipeline is connected to an inert gas, and one end of the first precursor source branch pipeline is connected to a first precursor. The second input pipeline system includes a second inert gas branch pipeline and a second precursor source branch pipeline; one end of the second inert gas branch pipeline is connected to an inert gas, and one end of the second precursor source branch pipeline is connected to a second precursor. The atomic layer deposition process specifically includes the following steps: S1. Sample pretreatment: Pretreatment of the sample substrate to be deposited; S2, First precursor deposition: The pretreated sample substrate to be deposited is placed in the reaction chamber, the outlet valve is closed, the first precursor is introduced into the reaction chamber through the first input pipeline system and deposited on the sample substrate. After the reaction is completed, the introduction of the first precursor is stopped. S3. Purging: Open the outlet valve and purge the reaction chamber with inert gas through the first input pipeline system until the gas pressure in the reaction chamber is P1; then close the outlet valve and stop the inert gas supply. Use a vacuum pump to evacuate the reaction chamber until the gas pressure in the reaction chamber is P2. After the evacuation is completed, stop the inert gas supply; P1 is greater than P2. S4. Second precursor deposition: The second precursor is introduced into the reaction chamber through the second input pipeline system and deposited on the sample substrate. After the reaction is completed, the introduction of the second precursor is stopped. S5. Purging: Open the outlet valve and purge the reaction chamber with inert gas through the second input pipeline system until the gas pressure in the reaction chamber is P3; then close the outlet valve and stop the inert gas supply. Use a vacuum pump to evacuate the reaction chamber until the gas pressure in the reaction chamber is P4. After the evacuation is completed, stop the inert gas supply; P3 is greater than P4. S6. Repeat steps S2-S5 above to obtain a thin film on the sample substrate surface.

2. The atomic layer deposition method as described in claim 1, characterized in that, The first input pipeline system also includes a first main pipeline, wherein the first inert gas branch pipeline and the first precursor source branch pipeline intersect and converge before the air inlet to form the first main pipeline; And / or, the second input piping system further includes a second main pipeline, wherein the second inert gas branch pipeline intersects and converges with the second precursor source branch pipeline before the air inlet to form the second main pipeline.

3. The atomic layer deposition method as described in claim 1, characterized in that, In the atomic layer deposition system, the outlet valve includes at least one of an angle valve and a butterfly valve; when the butterfly valve is open, the opening degree of the butterfly valve is 10°-90°, and when the butterfly valve is closed, the opening degree of the butterfly valve is 0°.

4. The atomic layer deposition method as described in claim 1, characterized in that, In step S1, the sample substrate to be deposited has a porous structure; the porous structure includes an irregular porous structure, wherein the upper and lower pore diameters of the irregular porous structure are not the same, and the pore centers are not on the same vertical line, the upper pore diameter is 1-3 mm, and the lower pore diameter is 0.05-1 mm; and / or, the depth-to-width ratio of the porous structure is (20-50):

1.

5. The atomic layer deposition method as described in claim 1, characterized in that, In steps S2 and S4, the deposition reaction time is independently selected from 1-10s; the deposition reaction temperature is independently selected from 100-300℃.

6. The atomic layer deposition method as described in claim 1, characterized in that, In step S2, when the first precursor is introduced into the reaction chamber, the temperature of the first precursor source branch pipe in the atomic layer deposition system is 50-200°C; and / or, in step S4, when the second precursor is introduced into the reaction chamber, the temperature of the second precursor source branch pipe in the atomic layer deposition system is 50-200°C.

7. The atomic layer deposition method as described in claim 1, characterized in that, In steps S3 and S5, P1 and P3 are each independently selected from 5-20 torr, P2 and P4 are each independently selected from 0.1-3 torr, and the flow rate of the inert gas is 5-2000 sccm.

8. The atomic layer deposition method as described in claim 1, characterized in that, The deposition reaction may be repeated two or more times in accordance with step S2, and / or, the deposition reaction may be repeated two or more times in accordance with step S4.

9. The atomic layer deposition method as described in claim 1, characterized in that, Perform the purging process two or more times in accordance with step S3, and / or perform the purging process two or more times in accordance with step S5.

10. A thin film, characterized in that, It is prepared by the atomic layer deposition method according to any one of claims 1-9.

Images