Pretreatment method for improving growth self-limiting property of ALD (Atomic Layer Deposition) film
By using the ion implantation pretreatment method in the ALD process, the affinity between the ALD film and the matrix is improved, and the problem of poor surface quality of the ALD film in the matrix with poor wettability is solved, achieving higher film uniformity and quality.
Patent Information
- Application Number
- CN202411841269.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-13
- Publication Date
- 2025-03-18
AI Technical Summary
The atomic layer deposition (ALD) process is limited in the process of deposition of ALD films on the substrate surface with poor wetting properties, resulting in poor quality of ALD films.
By ion implantation pretreatment method, the affinity between the ALD film and the substrate is improved by performing ion implantation on the surface of the substrate, thereby improving the uniformity and quality of the ALD film.
Through ion implantation pretreatment, the growth self-limiting of ALD film is improved, the uniformity and quality of the film are improved, and the application range of ALD film is broadened.
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Abstract
Description
Technical Field
[0001] The invention relates to the field of material surface engineering. Background Art
[0002] Atomic layer deposition (ALD) is a new process for depositing thin films based on ordered, self-saturated surface reactions. It has the characteristic of self-limiting, that is, each layer of atoms will not continue to react after the surface reaction is completed. This results in the thin films deposited using this process being uniform, dense, continuous and well conformal. However, the thin films deposited by the ALD process are greatly affected by the substrate surface, and the uniformity and other properties of ALD films grown on different surfaces will vary, which will in turn affect the quality and performance of the ALD films.
[0003] At present, the more commonly used ALD substrate pretreatment method is chemical surface pretreatment, that is, regulating the structure, functional groups, and reactive sites on the substrate surface through chemical reactions. Chemical surface pretreatment has the disadvantages of limited total types of active groups introduced and the possible introduction of additional pollutants. There are few chemical surface pretreatment processes that can accurately regulate the substrate surface structure and the concentration of introduced surface functional groups and reactive sites. There is no commonly used pretreatment process that can meet the requirements of introducing multiple elements and reactive sites on the substrate at the same time. Summary of the invention
[0004] The purpose of the present invention is to provide a new and efficient pretreatment method that can improve the self-limitation of the ALD film growth process, broaden the application range of ALD films, and improve the film quality, in order to address the shortcomings and defects of the current atomic layer deposition (ALD) process, such as limited self-limitation of the ALD film deposition process on a substrate surface with poor wettability, resulting in poor quality of the ALD film.
[0005] To achieve the above object, the present invention provides a novel pretreatment method for improving the uniformity of ALD film, which is characterized by using ion implantation to improve the affinity between the ALD film and the substrate, thereby improving the uniformity of the ALD film deposited on the surface after pretreatment, and comprises the following steps:
[0006] Step 1: After cleaning the substrate surface, ion implantation is performed on the substrate surface under the working gas type, vacuum degree and other process parameters selected as needed; Step 2: The ion-implanted substrate is placed in the ALD reaction chamber to grow an ALD film on the substrate surface.
[0007] As a preferred embodiment, in the step 1, the cleaning includes ion cleaning.
[0008] As a preferred embodiment, the ion implantation type may be beam-line ion implantation or plasma immersion ion implantation; the implanted ions may be metal ions or non-metal ions.
[0009] As a preferred method, the ion source used in beam-line ion implantation can be a Kaufman ion source, a radio frequency ion source, or a MEVVA ion source; the ionization method of plasma immersion ion implantation can use an anode layer ion source or a Hall ion source, or can use magnetron sputtering discharge or vacuum cathode arc discharge to generate ions.
[0010] As a preferred embodiment, the energy range of the implanted ions in the ion implantation is 100 eV to 100 MeV.
[0011] As a preferred embodiment, the implanted ion element may be an element contained in the ALD film, or may be different from the element contained in the ALD film.
[0012] As a preferred embodiment, the aforementioned pretreatment method for improving the self-limitation of ALD film growth specifically comprises the following steps: step (1): cleaning the substrate with a solvent to remove macroscopic large particles or other impurities attached to the surface of the substrate; step (2): drying the substrate after surface cleaning and placing it in a vacuum chamber, and connecting the substrate to a glow cleaning power supply; step (3): evacuating the entire environment to a vacuum, and introducing a working gas to adjust the vacuum degree to 10 -1 Pa~10Pa; Step (4): Set the glow cleaning power supply voltage to 500V~1200V, turn on the glow power supply, and set the glow cleaning time to 1min~240min; Step (5): Turn off the glow cleaning power supply, adjust the air pressure to the pressure value required for ion implantation, and adjust the vacuum degree to 10 -1 Pa~10Pa; Step (6): Set the pulse width of the high-power pulse magnetron sputtering power supply connected to the cathode target to 3μs~1ms and the voltage to 200V~2000V; Set the pulse width of the high-voltage pulse power supply connected to the substrate to 10μs~400μs and the voltage to 5000V~150000V; Set the synchronization signal generator so that the frequencies of the two power supplies are the same, which is 5Hz~100kHz, and the high-voltage pulse power supply pulse delays the high-power pulse magnetron sputtering pulse by -200ms~200ms; Turn on the power supply and set the ion injection time according to the required injection dose; Step (7): Turn off all power supplies and the working gas, take out the sample from the vacuum chamber, and move it into the ALD reaction chamber to grow the ALD film.
[0013] As a preferred embodiment, the aforementioned pretreatment method for improving the self-limitation of ALD film growth specifically comprises the following steps: step (1): cleaning the substrate with a solvent to remove macroscopic large particles or other impurities attached to the surface of the substrate; step (2): drying the substrate after surface cleaning and placing it in a vacuum chamber, and connecting the substrate to a glow cleaning power supply; step (3): evacuating the entire environment to a vacuum, and introducing a working gas to adjust the vacuum degree to 10 -1 Pa~10Pa; Step (4): Set the glow cleaning power supply voltage to 500V~1200V, turn on the glow power supply, and set the glow cleaning time to 1min~240min; Step (5): Turn off the glow cleaning power supply, adjust the air pressure to the pressure value required for ion implantation, and adjust the vacuum degree to 10 -1 Pa~10Pa; Step (6): Start the Kaufman ion source, RF ion source, or MEVVA ion source for beam-line ion injection; Step (7): Turn off all power supplies and the working gas, take out the sample from the vacuum chamber, and move it into the ALD reaction chamber to grow the ALD film.
[0014] As a preferred embodiment, in the step (1), the cleaning of the substrate with a solvent is performed by ultrasonic cleaning using alcohol and then acetone as solvents.
[0015] As a preferred embodiment, in step (3), the vacuum is 10 -3 Pa level, and the working gas is argon.
[0016] Compared with the prior art, the present invention utilizes ion implantation pretreatment to perform surface modification pretreatment on the substrate surface. The core of the present invention is to use the ion implantation pretreatment method to improve the distribution of active sites on the substrate surface, thereby improving the performance of the substrate surface, promoting the self-limitation of the ALD process, and improving the quality of the ALD film.
[0017] The present invention mainly uses ion implantation to improve the affinity between the ALD film and the substrate, thereby improving the uniformity of the ALD film deposited on the surface after pretreatment. The present invention can also use ion cleaning as an auxiliary to further improve the affinity between the ALD film and the substrate, thereby making the uniformity of the ALD film deposited on the surface after pretreatment better.
[0018] Compared with the prior art, the ion implantation process used in the present invention can improve the surface performance of the substrate without introducing other contaminations and is not limited by materials.
[0019] The method of the present invention is simple, practical, easy to operate, can be applied to a wide range of materials, and can also accurately control the degree of improvement in substrate surface properties and break through the limitations of material element types, thus having broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only used to explain the concept of the present invention.
[0021] Figure 1 A schematic diagram of the process flow for implementing a pretreatment method for improving the self-limitation of ALD film growth.
[0022] Figure 2 Scanning electron microscope photos of the ALD film surface morphology comparison for the implementation of a pretreatment method to improve the self-limitation of ALD film growth.
[0023] Figure 3 ALD film thickness comparison chart for the implementation of a pretreatment method to improve the self-limitation of ALD film growth. DETAILED DESCRIPTION
[0024] Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.
[0025] The embodiments described herein are specific embodiments of the present invention, which are used to illustrate the concept of the present invention, are illustrative and exemplary, and should not be interpreted as limiting the embodiments of the present invention and the scope of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the claims and the contents disclosed in the specification of this application, including any obvious replacement and modification of the embodiments described herein.
[0026] The drawings of this specification are schematic diagrams, which assist in explaining the concept of the present invention and schematically show the shapes of various parts and their mutual relationships. Please note that in order to clearly show the structures of various parts of the embodiments of the present invention, the drawings are not necessarily drawn in the same proportion.
[0027] Figure 1 A schematic diagram of the process flow for implementing a pretreatment method for improving the self-limitation of ALD film growth.
[0028] Example 1: In this embodiment, the base material is powder metallurgy Re metal, the solvents selected for surface cleaning are alcohol and acetone, the ion cleaning method is glow cleaning, and the ion implantation method is plasma immersion ion implantation after high-power pulsed magnetron sputtering to generate ions, wherein high-purity Ir metal is the magnetron sputtering cathode.
[0029] In this example 1, the selected materials and process methods are only used as examples. Those skilled in the art can select specific materials, working gas types, vacuum degrees and other process parameters as needed. For example, the surface cleaning solvent can be other solvents such as tetrachloromethane, the ion cleaning process can also be chemical reaction ion cleaning, the ion implantation process can also be beam-line ion implantation, and so on.
[0030] Please note that in the present invention, ion implantation is mainly used to improve the affinity between the ALD film and the substrate, thereby improving the uniformity of the ALD film deposited on the surface after pretreatment. However, the present invention can also use ion cleaning as an auxiliary to further improve the affinity between the ALD film and the substrate, thereby making the uniformity of the ALD film deposited on the surface after pretreatment better.
[0031] The specific steps of Example 1 are as follows:
[0032] Step (1): using alcohol and acetone as solvents, ultrasonically cleaning the substrate to remove large macroscopic particles or other impurities attached to the surface of the substrate.
[0033] Step (2): After the surface of the cleaned substrate is dried, it is placed in a vacuum chamber and the substrate is connected to a glow cleaning power supply.
[0034] Step (3): Evacuate the entire environment to a vacuum (10 -3 Pa level), and introduced working gas argon (Ar) to adjust the vacuum degree to 10 -1 Pa~10Pa.
[0035] Step (4): Set the glow cleaning power supply voltage to 500V to 1200V, turn on the glow power supply, and set the glow cleaning time to 1min to 240min.
[0036] Step (5): Turn off the glow cleaning power supply, adjust the air pressure to the pressure required for ion implantation, and adjust the vacuum degree to 10 -1 Pa~10Pa.
[0037] Step (6): Set the pulse width of the high-power pulse magnetron sputtering power supply connected to the cathode target to 3μs to 1ms and the voltage to 200V to 2000V; set the pulse width of the high-voltage pulse power supply connected to the substrate to 10μs to 400μs and the voltage to 5000V to 150000V; set the synchronization signal generator so that the two power supplies have the same frequency of 5Hz to 100kHz, and the high-voltage pulse power supply pulse delays the high-power pulse magnetron sputtering pulse by -200ms to 200ms. Turn on the power supply and set the ion injection time according to the required injection dose.
[0038] Step (7): Turn off all power supplies and argon (Ar), remove the sample from the vacuum chamber, and move it into the ALD reaction chamber to grow an ALD film.
[0039] Please note that the above Example 1 is only for explaining an exemplary embodiment of the present invention. In the present invention, the ion implantation type can be beam-line ion implantation, plasma immersion ion implantation or other ion implantation types; the implanted ions can be metal ions or non-metal ions.
[0040] The implanted ion elements may be the elements contained in the ALD film, or may be different from the elements contained in the ALD film.
[0041] Regarding the type of ion implantation, the ion source used for beam-line ion implantation can be a Kaufman ion source, a radio frequency ion source, a MEVVA ion source or other types of ion sources; the ionization method of plasma immersion ion implantation can use an ion source such as an anode layer ion source, a Hall ion source or other types of ion sources, or it can use magnetron sputtering discharge, vacuum cathode arc discharge and other methods to generate ions.
[0042] The injection voltage range of ion implantation is 100eV to 100MeV.
[0043] Cleaning can be performed before ion implantation, and the cleaning type can be surface cleaning, ion cleaning or other cleaning methods.
[0044] Surface cleaning solvents include organic solvents such as acetone and alcohol, as well as inorganic solvents such as high-purity water.
[0045] The ion cleaning process may be as follows: placing the substrate in a vacuum chamber and evacuating the chamber, and performing ion cleaning on the surface of the substrate under appropriate working gas and working gas pressure.
[0046] The ion cleaning process can be chemical reaction ion cleaning, physical reaction ion cleaning or a mixed reaction cleaning of the two.
[0047] The ion cleaning process can generate ions using an ion source or by ionizing the gas by applying a negative voltage to the substrate (glow cleaning).
[0048] The working gas can be an inert gas or a reactive gas or a mixed gas of several gases.
[0049] Ion cleaning vacuum can be 10 -3 Pa~10 3 Pa.
[0050] The ion implantation vacuum can be 10 -3 Pa~10Pa.
[0051] Figure 2Scanning electron microscope photos of the ALD film surface morphology comparison for the implementation of a pretreatment method to improve the self-limitation of ALD film growth.
[0052] After implementing Example 1, a scanning electron microscope was used to characterize the effect of the comparative pretreatment method on the surface morphology of the ALD film. By observing the surface morphology of the deposited ALD film, it was found that the ALD film grown on the surface after ion implantation pretreatment had a higher nucleation density, a tighter grain arrangement, a more uniform grain size, and no obvious scratches running through the image. The ALD film had better growth uniformity and higher quality.
[0053] Figure 3 ALD film thickness comparison chart for the implementation of a pretreatment method to improve the self-limitation of ALD film growth.
[0054] After implementing Example 1, the effect of the pretreatment method on the thickness of the ALD film was characterized and compared using time-of-flight-secondary ion mass spectrometry. By observing the thickness of the deposited ALD film, it can be found that the film thickness is smaller after ion implantation pretreatment, while the ALD film grown on the unpretreated surface is thicker.
[0055] The above describes the pretreatment method and implementation method of the present invention, as well as the results after implementation. For the specific features of the method of the present invention, such as the pretreatment including two processes of ion cleaning and ion implantation, the use of ion implantation process to achieve the modification of the surface structure of the material and the introduction of other elements, specific designs can be made according to the effects of the above-disclosed features, and these designs are all achievable by those skilled in the art. Moreover, the above-disclosed technical features are not limited to the disclosed combinations with other features, and those skilled in the art can also make other combinations between the technical features according to the purpose of the present invention, so as to achieve the purpose of the present invention.
Claims
1. A pretreatment method for improving the self-limiting property of ALD film growth, characterized in that Ion implantation is used to improve the affinity between the ALD film and the substrate, thereby improving the uniformity of the ALD film deposited on the surface after pretreatment, including the following steps: Step 1: After cleaning the substrate surface, ion implantation is performed on the substrate surface under the working gas type, vacuum degree and other process parameters selected as required; Step 2: Place the ion-implanted substrate into the ALD reaction chamber and grow an ALD film on the surface of the substrate.
2. A pretreatment method for improving the self-limitation of ALD film growth according to claim 1, wherein: In the step 1, the cleaning includes ion cleaning.
3. According to a pretreatment method for improving the self-limitation of ALD film growth as described in claim 1 or 2, the ion implantation type can be beam-line ion implantation or plasma immersion ion implantation; the implanted ions can be metal ions or non-metal ions.
4. According to the pretreatment method for improving the self-limitation of ALD film growth described in claim 3, the ion source used in beam-line ion implantation can be a Kaufman ion source, a radio frequency ion source, or a MEVVA ion source; the ionization method of plasma immersion ion implantation can use an anode layer ion source or a Hall ion source, or can use magnetron sputtering discharge or vacuum cathode arc discharge to generate ions.
5. According to the pretreatment method for improving the self-limitation of ALD film growth according to claim 1 or 2, the energy range of the implanted ions in the ion implantation is 100eV to 100MeV.
6. According to the pretreatment method for improving the self-limitation of ALD film growth as described in claim 1 or 2, the implanted ion elements can be elements contained in the ALD film, and can also be different from the elements contained in the ALD film.
7. A pretreatment method for improving the self-limitation of ALD film growth according to claim 1, comprising the following steps: Step (1): cleaning the substrate with a solvent to remove macroscopic large particles or other impurities attached to the surface of the substrate; Step (2): drying the substrate after surface cleaning and placing it in a vacuum chamber, and connecting the substrate to a glow cleaning power supply; Step (3): Evacuate the entire environment and introduce working gas to adjust the vacuum degree to 10 -1 Pa~10Pa; Step (4): Set the glow cleaning power supply voltage to 500V to 1200V, turn on the glow power supply, and set the glow cleaning time to 1min to 240min; Step (5): Turn off the glow cleaning power supply, adjust the air pressure to the pressure required for ion implantation, and adjust the vacuum degree to 10 -1 Pa~10Pa; Step (6): setting the pulse width of the high-power pulse magnetron sputtering power supply connected to the cathode target to 3μs to 1ms and the voltage to 200V to 2000V; setting the pulse width of the high-voltage pulse power supply connected to the substrate to 10μs to 400μs and the voltage to 5000V to 150000V; setting the synchronization signal generator so that the two power supplies have the same frequency of 5Hz to 100kHz, and the high-voltage pulse power supply pulse delays the high-power pulse magnetron sputtering pulse by -200ms to 200ms; turning on the power supply, and setting the ion injection time according to the required injection dose; Step (7): Turn off all power supplies and the working gas, take out the sample from the vacuum chamber, and move it into the ALD reaction chamber to grow the ALD film.
8. The pretreatment method for improving the self-limitation of ALD film growth according to claim 1, comprising the following steps: Step (1): cleaning the substrate with a solvent to remove macroscopic large particles or other impurities attached to the surface of the substrate; Step (2): drying the substrate after surface cleaning and placing it in a vacuum chamber, and connecting the substrate to a glow cleaning power supply; Step (3): Evacuate the entire environment and introduce working gas to adjust the vacuum degree to 10 -1 Pa~10Pa; Step (4): Set the glow cleaning power supply voltage to 500V to 1200V, turn on the glow power supply, and set the glow cleaning time to 1min to 240min; Step (5): Turn off the glow cleaning power supply, adjust the air pressure to the pressure required for ion implantation, and adjust the vacuum degree to 10 -1 Pa~10Pa; Step (6): starting the Kaufman ion source, the radio frequency ion source, or the MEVVA ion source to perform beamline ion implantation; Step (7): Turn off all power supplies and the working gas, take out the sample from the vacuum chamber, and move it into the ALD reaction chamber to grow the ALD film.
9. A pretreatment method for improving the self-limitation of ALD film growth according to claim 7 or 8, wherein: In the step (1), the cleaning of the substrate with a solvent is performed by ultrasonic cleaning using alcohol and acetone as solvents in sequence.
10. A pretreatment method for improving the self-limitation of ALD film growth according to claim 7 or 8, wherein: In step (3), the vacuum is 10 -3 Pa level, and the working gas is argon.