Atomic layer deposition method

Abstract

The present invention is a method for achieving single-sided atomic layer deposition of a sample in each single cycle. By controlling the polarity of both sides of the sample and the charge carried by the precursor, the precursor can be selectively adsorbed to the specified side of the sample. In order to achieve single-sided atomic layer deposition on the specified side of the sample in a single cycle, the present invention does not require pasting, gluing, photolithography, etching, cleaning and other operations on the sample. The method of the present invention can well solve the problem of back-side plating of atomic layer deposition. During the atomic layer deposition process, single-sided atomic layer deposition of the sample is achieved, and the side of the sample to be deposited can be switched at any time during the reaction process. One deposition process can achieve deposition of different thicknesses and different materials on both sides of the sample according to the coating requirements.

Description

Technical Field

[0001] The invention belongs to the field of atomic layer deposition coating, and relates to a method for realizing single-side atomic layer deposition of a sample in each single cycle. Background Art

[0002] Atomic layer deposition (ALD) is a thin-film deposition technology that deposits uniform, controllable thickness, and adjustable composition ultra-thin films. With the advancement of nanotechnology and semiconductor microelectronics, device and material dimensions are continuously decreasing, while the aspect ratio of device structures is increasing, requiring material thicknesses to be reduced to tens to several nanometers. ALD has become an irreplaceable technology in related manufacturing fields. Its advantages guarantee enormous development potential and a broad range of applications.

[0003] This method has many advantages: for example, good uniformity, controllable thickness, dense film, good three-dimensional shape retention, etc. However, there is an insurmountable disadvantage, which is the problem of back-wrap plating. In many cases, we only need to deposit on one side of the sample, but ALD deposition will also deposit a thin film on the back of the sample, especially on the edge. The traditional solution is to place the sample tightly on a platform and glue all four sides tightly to prevent the reaction gas from diffusing in, or to place two samples that require single-sided atomic layer deposition tightly together back to back, with the surfaces to be deposited facing outward. Even so, the wrap-around plating phenomenon cannot be completely overcome. Affected by the roughness and morphology of the back of the sample, wrap-around plating of several millimeters to several centimeters will occur on the back. Or by adding processes such as coating, photolithography, etching, and cleaning, the coating time is longer, which greatly increases the process complexity and equipment cost of the deposition.

[0004] Compared with existing patent disclosures, the significant advantages of the patent application of the present invention are: First, there is no need to perform operations such as pasting, gluing, photolithography, etching, and cleaning on the sample, and the sample can be coated with atomic layer deposition on one side in each single cycle. Second, the method of the present invention can well solve the problem of back-side plating of atomic layer deposition. Third, the side of the sample to be deposited can be switched at any time during the reaction process. In one deposition process, different thicknesses and different materials can be deposited on both sides of the sample according to the coating requirements. Summary of the Invention

[0005] The present invention aims to address the issues of backside plating in existing atomic layer deposition (ALD) technology by providing a method for achieving single-sided ALD on a wafer in each single cycle. The wafer is polarized under the action of an electric field, resulting in a positive charge on one side (e.g., the S side) and a negative charge on the other side (e.g., the N side). A first precursor (e.g., positively charged) with the same charge is then introduced. The positively charged first precursor chemically adsorbs to the negatively charged N side of the wafer. After the unadsorbed first precursor is removed, a second precursor is introduced. The second precursor chemically reacts with the first precursor adsorbed on the N side, removing the second precursor and reaction byproducts, completing a single cycle. Because like charges repel each other, the positively charged first precursor will not adsorb to the positively charged S side of the wafer. This single cycle allows ALD on a single side of the wafer. The wafer is then polarized again under the action of an electric field, followed by the introduction of the first precursor with the same charge, followed by evacuation, the second precursor, and finally evacuation. These steps are repeated until the desired thin film is formed.

[0006] Specifically, the reaction chamber of the atomic layer deposition equipment is equipped with an initially uniform electric field. This field is generated using two parallel plates, each loaded with an adjustable DC voltage to adjust the field strength. The DC voltage range is 0-1000V, and the spacing between the plates is 1mm-500mm.

[0007] The sample is placed in the electric field perpendicular to the direction of the electric field. Before the first precursor pulse enters the reaction chamber, the distance between the two electrodes is adjusted and the DC voltage value of the electric field is set to polarize the sample. After the sample is polarized, one side of the sample is positively charged and the other side is negatively charged.

[0008] A first precursor with the same charge is introduced, and the first precursor with the same charge is chemically adsorbed on the oppositely charged side of the sample. The first precursor can be made to have the same charge by ionization; or the first precursor can be made to have the same charge by electric field polarization, electrostatic induction, etc. The first precursor can be treated in the precursor bottle or input pipeline before being introduced into the reaction chamber to have the same charge, or the first precursor can be introduced into the reaction chamber first and then quickly activated in the reaction chamber to have the same charge. Under the action of the electric field force, the first precursor with the same charge is chemically adsorbed on the oppositely charged side of the sample. For example, the first precursor A+ with a positive charge is chemically adsorbed on the negatively charged N side of the sample under the action of the electric field force, and the unadsorbed first precursor is drawn away. Similarly, the first precursor can also be processed to have a completely negative charge, that is, A-. Then, under the action of the electric field force, the negatively charged first precursor A- is chemically adsorbed on the positively charged S side of the sample, and the unadsorbed first precursor is removed. Since like charges repel each other, first precursors with the same charge will not be adsorbed to the side of the sample with the same charge. This ensures that first precursors with the same charge will only be chemically adsorbed on a certain side of the sample. According to the specific coating requirements of the sample, the charge of the first precursor can be selected and deposited on the specified side of the sample, while there will be no chemical adsorption on the other side, solving the plating bypass problem of existing atomic layer deposition technology.

[0009] The second precursor is introduced, and the second precursor reacts chemically with the first precursor adsorbed on the sample. The second precursor and the reaction by-products are extracted to complete a single cycle.

[0010] Furthermore, the electric field can be turned off before removing the unabsorbed first precursor and introducing the second precursor. At this point, some of the introduced second precursor chemically reacts with the first precursor adsorbed on the sample, while some is also adsorbed on the other side of the sample. However, this side of the sample is devoid of the first precursor. Therefore, throughout, the second precursor only has an atomically thin adsorption layer on this side of the sample, preventing any chemical reaction and depositing a nanofilm. The unabsorbed second precursor and reaction byproducts are then removed.

[0011] Furthermore, after the unadsorbed first precursor is extracted, the electric field is not turned off, and a second precursor with the same charge is introduced. For example, as mentioned above, if the electric field is not turned off, the side of the sample adsorbed with the first precursor A is the N side with a negative charge. Then, the second precursor needs to be processed into B+ with a positive charge. The second precursor can be converted into B+ with a complete positive charge by ionization; or the second precursor can be given a positive charge by electric field polarization, electrostatic induction, etc. In this way, under the action of the electric field force, the second precursor B+ with a positive charge reacts chemically with the first precursor A on the N side of the sample adsorbed with the first precursor A with a negative charge. Since like charges repel each other, the second precursor B+ with a positive charge will not be adsorbed to the S side of the sample with a positive charge.

[0012] Furthermore, after the unadsorbed first precursor is extracted, the electric field is not turned off, and a second precursor with the same charge is introduced. The electric field can change direction. Then, as mentioned above, after the direction of the electric field is changed, the N side of the sample adsorbed with the first precursor A is positively charged. Then, the second precursor needs to be treated to have a negative charge B-. In this way, under the action of the electric field force, the negatively charged second precursor B- reacts chemically with the first precursor A adsorbed on the positively charged N side of the sample. Since like charges repel each other, the negatively charged second precursor B- will not be adsorbed to the negatively charged S side of the sample. Similarly, the second precursor can be treated in the precursor bottle or input pipeline before being introduced into the reaction chamber to carry the same charge, or the second precursor can be introduced into the reaction chamber first and then quickly activated in the reaction chamber to carry the same charge.

[0013] That is, when the second precursor is introduced, the electric field can be turned off or on. The direction of the electric field can be changed, and the second precursor of the same charge can be introduced according to the different polarization conditions of the two surfaces of the sample caused by the direction of the electric field.

[0014] Furthermore, through the above method, the first precursor and the second precursor can be introduced and adsorbed to the N side of the sample, and after several cycles, the preset film thickness is reached. However, there is no nanofilm deposition on the S side of the sample from beginning to end. Subsequently, the third precursor and the fourth precursor are introduced, and the third precursor and the fourth precursor are adsorbed to the N side of the sample using the same method as above, to achieve the preset film thickness. Similarly, the fifth precursor and the sixth precursor are introduced, and the fifth precursor and the sixth precursor are adsorbed to the N side of the sample using the same method as above, to achieve the preset film thickness. Using this method, single-sided atomic layer deposition can be achieved on a specific single side of the sample, while there is no nanofilm deposition on the other side, which perfectly solves the problem of back-side plating of atomic layer deposition. Using this method, one or more nanofilm materials can be deposited on a specific deposition surface of the sample, while the nanofilm material will not be deposited on the other side.

[0015] Furthermore, the sample is provided with a grounding device for conducting away the charges accumulated on the surface of the sample.

[0016] This method can realize single-sided atomic layer deposition coating of the sample in each single cycle. The side of the sample that needs to be deposited can be switched at any time during the reaction process. A single deposition process can realize the deposition of different thicknesses and different materials on both sides of the sample according to the coating requirements. As mentioned above, by controlling the polarity of the two sides of the sample and the charge carried by the precursor, the precursor can be selectively adsorbed to the specified side of the sample. For example, the first precursor and the second precursor that are respectively introduced are adsorbed to the N side of the sample, and after several cycles, the preset film thickness is reached. By changing the direction of the electric field or changing the same charge carried by the precursors, the third precursor and the fourth precursor are adsorbed to the S side of the sample, and after several cycles, the preset film thickness is reached. The third precursor may be the same as or different from the first precursor, and the fourth precursor may be the same as or different from the second precursor.

[0017] Specifically, the reaction chamber of the atomic layer deposition equipment is equipped with an initially uniform electric field. This field is generated using two parallel plates, each loaded with an adjustable DC voltage to adjust the field strength. The DC voltage range is 0-1000V, and the spacing between the plates is 1mm-500mm.

[0018] The sample is placed in the electric field perpendicular to the direction of the electric field. Before the first precursor pulse enters the reaction chamber, the distance between the two electrodes is adjusted and the DC voltage value of the electric field is set to polarize the sample. After the sample is polarized, one side of the sample is positively charged and the other side is negatively charged.

[0019] A first precursor with the same charge is introduced, and the first precursor with the same charge is chemically adsorbed on the oppositely charged side of the sample. For example, the first precursor A+ with a positive charge is chemically adsorbed on the negatively charged N side of the sample, and the unadsorbed first precursor is removed. Since the same charges repel each other, the first precursor with the same charge will not be adsorbed on the side of the sample with the same charge. This ensures that the first precursor with the same charge will only be chemically adsorbed on a certain side of the sample. According to the specific coating requirements of the sample, the charge of the first precursor can be selected and deposited on the specified side of the sample, while there will be no chemical adsorption on the other side, which solves the bypass plating problem of the existing atomic layer deposition technology.

[0020] The second precursor is introduced, and the second precursor reacts chemically with the first precursor adsorbed on the sample. The second precursor and the reaction by-products are extracted to complete a single cycle.

[0021] Furthermore, the electric field can be turned off before removing the unabsorbed first precursor and introducing the second precursor. At this point, some of the introduced second precursor chemically reacts with the first precursor adsorbed on the sample, while some is also adsorbed on the other side of the sample. However, this side of the sample is devoid of the first precursor, so the second precursor only has an atomic-layer-thick adsorption layer on this side of the sample. The unabsorbed second precursor and reaction byproducts are then removed.

[0022] Furthermore, after the unadsorbed first precursor is extracted, the electric field is not turned off, and a second precursor with the same charge is introduced. For example, as mentioned above, if the electric field is not turned off, the side of the sample adsorbed with the first precursor A is the N side with a negative charge. Then, the second precursor needs to be processed into B+ with a positive charge. The positively charged second precursor B+ reacts chemically with the negatively charged first precursor A on the N side of the sample adsorbed with the first precursor A. Since like charges repel each other, the positively charged second precursor B+ will not be adsorbed to the positively charged S side of the sample.

[0023] Furthermore, after the unadsorbed first precursor is extracted, the electric field is not turned off, and a second precursor with the same charge is introduced. The electric field can change direction. As mentioned above, after the direction of the electric field is changed, the N side of the sample adsorbed with the first precursor A is now positively charged. Then, the second precursor needs to be treated to have a negative charge B-. In this way, under the action of the electric field force, the second precursor B- with a negative charge reacts chemically with the first precursor A adsorbed on the positively charged N side of the sample. Similarly, since like charges repel each other, the second precursor B- with a negative charge will not be adsorbed to the negatively charged S side of the sample. In other words, when the second precursor is introduced, you can choose to turn off the electric field or turn on the electric field. The direction of the electric field can be changed, and according to the different polarization conditions of the two surfaces of the sample caused by the direction of the electric field, second precursors of the same charge under different conditions are introduced.

[0024] Furthermore, the above method can achieve that the first and second precursors are adsorbed onto the N-side of the sample, and after several cycles, the predetermined film thickness is reached, while no nanofilm is deposited on the S-side of the sample.

[0025] Similarly, the third and fourth precursors are introduced and adsorbed onto the S-side of the sample using the same method described above, achieving the desired film thickness. During the deposition process, each single cycle achieves single-sided atomic layer deposition on the designated surface. Throughout the deposition process, one or more nanofilm materials can be deposited on both the N-side and S-side of the sample, depending on the desired coating requirements. The deposited materials on both sides can be the same or different.

[0026] Furthermore, the precursors can be charged with the same charge by ionization, electric field polarization, electrostatic induction, etc. The precursors can be treated in the precursor bottle or input pipeline before entering the reaction chamber to carry the same charge, or the precursors can be first introduced into the reaction chamber and then quickly activated in the reaction chamber to carry the same charge.

[0027] Furthermore, the sample is provided with a grounding device for conducting away the charges accumulated on the surface of the sample.

[0028] All features disclosed in this specification, or all steps in the disclosed methods or processes, except mutually exclusive features and / or steps, can be combined in any manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The single cycle single-sided atomic layer deposition process of the present invention Figure 1 .

[0030] Figure 2 The single cycle single-sided atomic layer deposition process of the present invention Figure 2 .

[0031] Figure 3 The single cycle single-sided atomic layer deposition process of the present invention Figure 3 .

[0032] Figure 4 The single cycle single-sided atomic layer deposition process of the present invention Figure 4 .

[0033] Description of the accompanying drawings.

[0034] 11—Electric field; 12—Sample; 121—N surface; 122—S surface. DETAILED DESCRIPTION

[0035] Figure 1-4 It is a complete single-cycle single-sided atomic layer deposition process. The details are as follows.

[0036] like Figure 1 As shown, a sample 12 is placed in the reaction chamber of an atomic layer deposition apparatus, which is provided with an initially uniform electric field 11. Sample 12 is placed in the electric field 11 perpendicular to the electric field. At this point, the N-side 121 of sample 12 carries a negative charge, while the S-side 122 carries a positive charge.

[0037] like Figure 2 As shown, a first precursor A+ with a positive charge is introduced into the reaction chamber, and the first precursor A+ is chemically adsorbed on the N-surface 121 of the sample 12 with a negative charge.

[0038] like Figure 3 As shown, the unadsorbed first precursor A is drawn away. Since like charges repel each other, the positively charged first precursor A+ will not be adsorbed to the positively charged S surface 122 of the sample 12. The first precursor A forms a chemical adsorption layer on the N surface 121 of the sample 12.

[0039] like Figure 4 As shown, the electric field 11 is turned off, and the second precursor B is introduced into the reaction chamber. The second precursor B reacts with the first precursor A, and the unadsorbed second precursor B and reaction by-products are extracted to form a nanofilm with an atomic layer thickness on the N surface 121 of the sample 12.

[0040] At this point, a complete single-cycle single-sided atomic layer deposition process is completed. The second precursor B can be charged or uncharged during the introduction process. The electric field 11 can be turned on or off when the second precursor B is introduced. The second precursor B needs to react chemically with the first precursor A adsorbed on the N-side 121 of the sample 12, so when the second precursor B is introduced, the charge it carries and the electric field direction of the electric field 11 need to ensure that the second precursor B is adsorbed on the N-side 121 of the sample 12. Deposit the nanofilm thickness as needed and repeat the above steps.

[0041] Similarly, the third and fourth precursors are introduced and adsorbed onto the S-side 122 of the sample 12 using the same method described above, achieving a predetermined film thickness. During the deposition process, each single cycle of the sample 12 achieves single-sided atomic layer deposition on a designated surface. Throughout the deposition process, one or more nanofilm materials can be deposited on the N-side 121 and S-side 122 of the sample 12, depending on the actual coating requirements. The deposited materials on both sides can be the same or different.

[0042] In order to enable a more detailed understanding of the features and technical contents of the present invention, the implementation of the present invention is described in detail below. These embodiments are only for illustrative purposes and in no way limit the scope of protection of the present invention.

[0043] Example 1

[0044] A 4-inch single-side polished silicon wafer is placed in the atomic layer deposition (ALD) chamber and evacuated. The 4-inch wafer is positioned perpendicular to the electric field. A 30nm silicon oxide nanofilm is deposited on the polished surface of the wafer, while the unpolished surface does not require deposition.

[0045] Specifically, the electric field DC voltage is set to 200V, and the distance between the two electrodes is 100mm. For the convenience of description, the two electrodes are respectively referred to as the upper electrode plate and the lower electrode plate, the upper electrode plate is positively charged, and the lower electrode plate is negatively charged. The silicon wafer is placed 50mm away from the upper electrode plate. The polished surface of the silicon wafer faces the upper electrode plate. At this time, the polished surface of the silicon wafer is negatively charged, and the unpolished surface is positively charged. The first precursor tetramethylaminosilane is positively charged after passing through the electric field polarization device of the transmission pipeline. After the positively charged tetramethylaminosilane enters the reaction chamber, it is chemically adsorbed to the negatively charged polished surface of the silicon wafer. Since the unpolished surface of the silicon wafer is positively charged, the positively charged tetramethylaminosilane will not be adsorbed on this surface. The unadsorbed tetramethylaminosilane is cleaned by vacuum. At this time, a layer of tetramethylaminosilane is adsorbed on the polished surface of the silicon wafer. The electric field DC voltage is adjusted to 0V, effectively turning off the electric field. Ozone is then pulsed in, reacting chemically with the tetradimethylaminosilane on the polished surface of the silicon wafer to form silicon oxide. Since the unpolished surface of the silicon wafer lacks any other precursors, the ozone does not react there. Excess ozone and reaction byproducts are removed by vacuuming. At this point, a silicon oxide nanofilm with a thickness of approximately 1.0 Å and a thickness of one atomic layer is deposited on the polished surface of the silicon wafer. The electric field DC voltage is adjusted to 150V, with the upper plate positively charged and the lower plate negatively charged. Without changing the spacing between the plates or the placement of the silicon wafer, the tetradimethylaminosilane acquires a positive charge after passing through the electric field polarization device in the transmission pipeline. When the positively charged tetradimethylaminosilane is introduced, it chemically adsorbs onto the negatively charged silicon oxide on the polished surface of the silicon wafer. Excess tetradimethylaminosilane is then removed by vacuuming. The ozone acquires a positive charge after passing through the electric field polarization device in the transmission pipeline. A pulse of positively charged ozone is then introduced, reacting with the negatively charged tetradimethylaminosilane on the polished surface of the silicon wafer to form a second layer of silicon oxide nanofilm. This process is repeated 300 times, ultimately depositing a 30nm silicon oxide nanofilm on the polished surface of the 4-inch silicon wafer.

[0046] During the experiment, the DC voltage of the electric field, the distance between the two plates and the placement of the silicon wafer can be adjusted according to the specific experimental results.

[0047] The 4-inch single-side polished silicon wafer fixture is connected to a grounding device to conduct away the charge accumulated on the surface of the silicon wafer.

[0048] Example 2

[0049] A 400mm x 400mm glass sheet was placed in the reaction chamber of the atomic layer deposition (ALD) equipment and evacuated. The glass sheet was positioned perpendicular to the electric field. For ease of description, the two surfaces of the glass sheet are referred to as the upper and lower surfaces. A conductive nanofilm of titanium nitride was deposited on the upper surface, while a water and oxygen barrier film of aluminum oxide was deposited on the lower surface.

[0050] Specifically, the electric field DC voltage is set to 1000V, and the distance between the two plates is 500mm. For the convenience of description, the two plates are respectively referred to as the upper plate and the lower plate, the upper plate is positively charged, and the lower plate is negatively charged. The glass sheet is placed 450mm away from the upper plate, with the upper surface of the glass sheet facing the upper plate of the electric field. At this time, the upper surface of the glass sheet is negatively charged, and the lower surface is positively charged. The first precursor, tetrakis(dimethylamino)titanium pulse enters the reaction chamber and is ionized by microwave plasma daughters, carrying a positive charge. The positively charged tetrakis(dimethylamino)titanium is chemically adsorbed onto the negatively charged upper surface of the glass, and the unadsorbed tetrakis(dimethylamino)titanium is cleaned by vacuum. The electric field DC voltage is adjusted to 500V, the upper plate is positively charged, and the lower plate is negatively charged. At this time, the upper surface of the glass sheet is negatively charged, and the lower surface is positively charged. The second precursor, ammonia gas pulse enters the reaction chamber and is ionized by microwave plasma daughters, carrying a positive charge. The positively charged ammonia reacts with the negatively charged titanium tetradimethylamino on the upper surface of the glass, forming a titanium nitride nanofilm. This process is repeated until a predetermined thickness of titanium nitride nanofilm is deposited. At this point, no nanofilm is deposited on the lower surface of the glass.

[0051] The electric field DC voltage is adjusted to 50V, the upper electrode plate is positively charged, and the lower electrode plate is negatively charged. The distance between the two electrodes is adjusted to 50mm, and the glass plate deposited with titanium nitride is placed 20mm away from the upper electrode plate. At this time, a titanium nitride nanofilm is deposited on the upper surface of the glass plate, which is negatively charged, and the lower surface of the glass plate is positively charged. The third precursor, trimethylaluminum, is negatively charged through electrostatic induction in the precursor cylinder and pulsed into the reaction chamber. The negatively charged trimethylaluminum is chemically adsorbed onto the lower surface of the positively charged glass plate, and the unadsorbed trimethylaluminum is cleaned by vacuum. The negatively charged trimethylaluminum will not adsorb onto the negatively charged upper surface of the glass plate deposited with the titanium nitride nanofilm. The electric field DC voltage remains unchanged at 50V, and the direction of the current is changed. At this time, the upper electrode plate is negatively charged, and the lower electrode plate is positively charged. At this time, the upper surface of the glass plate is positively charged, and the lower surface is negatively charged. After passing through the electric field polarization device in the transmission line, the fourth precursor, deionized water, becomes positively charged and pulses into the reaction chamber. The positively charged deionized water reacts with the negatively charged trimethylaluminum on the lower surface of the glass sheet, forming an aluminum oxide nanofilm. This step is repeated until the aluminum oxide nanofilm reaches a predetermined thickness. At this point, the upper surface of the glass sheet is free of the aluminum oxide film, in addition to the previously deposited titanium nitride conductive film.

Claims

1. An atomic layer deposition method, characterized in that: The method is applied in a reaction chamber of an atomic layer deposition device, wherein an electric field having a relatively uniform initial state is provided in the reaction chamber, and a sample is placed in the reaction chamber, wherein the sample is placed in the electric field in a direction perpendicular to the electric field. The method comprises: Step 1: The sample is polarized under the action of an electric field, so that the two sides of the sample have different charges, one side has a positive charge and the other side has a negative charge; Step 2: introducing a charged first precursor into the reaction chamber, and chemically adsorbing the charged first precursor onto the oppositely charged side of the sample; Step 3: extracting the unadsorbed first precursor; Step 4: introducing a second precursor having the same charge as the first precursor into the reaction chamber, or changing the direction of the electric field to introduce a second precursor having an opposite charge to the first precursor into the reaction chamber, or turning off the electric field to introduce the second precursor into the reaction chamber, so that the second precursor and the first precursor undergo a chemical reaction; Step 5: Remove the unadsorbed second precursor and reaction by-products; Steps 1 to 5 are a single cycle. During the deposition process, each single cycle can achieve single-sided atomic layer deposition. Steps 1 to 5 are repeated until a predetermined thin film is formed on a single side of the sample. After forming a predetermined thin film on one side of the sample, the direction of the electric field is changed so that the charges on both sides of the sample are opposite to the charges before the direction of the electric field is changed. The third precursor and the fourth precursor are introduced using the same method as above. The third precursor with the same charge as the first precursor is introduced in step 2 and chemically adsorbed on the other side of the sample. The fourth precursor is introduced in step 4 and chemically reacts with the third precursor. After several cycles, the predetermined film thickness is reached. Alternatively, after forming a predetermined thin film on one side of the sample, the electric field direction is maintained unchanged, and the third precursor and the fourth precursor are introduced using the same method as above. The third precursor with a charge opposite to that of the first precursor is introduced in step 2 and chemically adsorbed onto the other side of the sample. The fourth precursor is introduced in step 4 and chemically reacts with the third precursor. After several cycles, the predetermined film thickness is reached. The first precursor and the third precursor are charged by ionization, electric field polarization or electrostatic induction.

2. The atomic layer deposition method according to claim 1, wherein: The electric field uses two parallel plates, and an adjustable DC voltage is loaded on the two plates to adjust the electric field strength; the sample is placed in parallel between the two plates; the area of ​​the sample that needs to be deposited is placed within the range of the uniform electric field.

3. The atomic layer deposition method according to claim 2, wherein: The DC voltage range of the electric field is 50 to 1000 V, and the distance between the two electrode plates is 1 mm to 500 mm.

4. The atomic layer deposition method according to claim 1, wherein: The first precursor and the third precursor are charged before entering the reaction chamber, or are charged after entering the reaction chamber.

5. The atomic layer deposition method according to claim 1, wherein: The charge carried by the first precursor is positive or negative; the charge carried by the third precursor is positive or negative.

6. The atomic layer deposition method according to claim 1, characterized in that: The sample is provided with a grounding device.

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