Processing method of period-adjustable micro-nano oxidation periodic structure

Abstract

The embodiment of the invention relates to the technical field of semiconductor material processing, in particular to a processing method of a period-adjustable micro-nano oxidation periodic structure, which comprises the following steps: sequentially preparing a substrate, a metal layer and a semiconductor layer from bottom to top by using a physical deposition method to form a substrate-metal layer-semiconductor layer structure film from bottom to top; a light path composed of a femtosecond laser, an optical half-wave plate, a polarization beam splitter prism and a cylindrical lens is built; a femtosecond laser device is used for emitting femtosecond laser in a pulse string mode, after the femtosecond laser sequentially passes through an optical half-wave plate, a polarization beam splitter prism and a cylindrical lens, linear light spots are formed and focused on the surface of a structural film, and a micro-nano oxidation periodic structure is obtained; by changing the number of sub-pulses of the femtosecond laser, regulation and control of the period of the processed micro-nano oxidation periodic structure are realized. According to the method, efficient, economical, batch and accurate preparation of the micro-nano oxidation periodic structure is realized, and the method has a wide industrial application prospect.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of semiconductor material processing technology, and in particular to a method for processing a periodically adjustable micro-nano oxidation periodic structure. Background Art

[0002] With the widespread application of micro-nano processing technology in materials science, biomedicine, optoelectronics and other fields, the demand for precise control of material surface properties is growing. Laser-induced periodic surface structure technology has attracted attention due to its ability to form a controllable periodic stripe structure on the surface of materials. This structure can significantly change the optical, mechanical and chemical properties of materials, such as reflectivity, roughness and wettability, to meet the needs of specific applications.

[0003] However, the inventors of this application have found that traditional micro-nanostructure processing technologies, such as electron beam exposure, focused ion beam etching, electron beam lithography and nanoimprinting, although with high precision, have problems such as high cost, complex operation and low efficiency. These technologies often require the use of expensive equipment and complex operating processes, which greatly limits their application in large-scale industrial production. In addition, these methods also face challenges in efficiency and uniformity when processing large-area materials. Summary of the invention

[0004] In view of this, the embodiments of the present application propose a processing method for a periodically adjustable micro-nano oxidation periodic structure. Through innovative structural design and laser parameter control, efficient, economical, batch and precise preparation of micro-nano oxidation periodic structures is achieved, which has broad industrial application prospects.

[0005] In the first aspect, an embodiment of the present application proposes a processing method for a periodically adjustable micro-nano oxidation periodic structure, comprising the following steps: using a physical deposition method to sequentially prepare a substrate, a metal layer and a semiconductor layer from bottom to top to form a substrate-metal layer-semiconductor layer structural film from bottom to top; constructing an optical path consisting of a femtosecond laser, an optical half-wave plate, a polarization beam splitter prism and a cylindrical lens; using a femtosecond laser to emit a pulse train mode of a femtosecond laser, which sequentially passes through an optical half-wave plate, a polarization beam splitter prism and a cylindrical lens to form a line spot focused on the surface of the structural film to obtain a micro-nano oxidation periodic structure; by changing the number of sub-pulses of the femtosecond laser, the period of the processed micro-nano oxidation periodic structure is regulated, and the period of the micro-nano oxidation periodic structure increases with the increase in the number of sub-pulses of the femtosecond laser.

[0006] In some optional embodiments, the metal material selected for the metal layer is one of platinum, gold, silver, titanium, copper, aluminum, nickel, or an alloy of any combination.

[0007] In some optional embodiments, the thickness of the metal layer is greater than 50 mm.

[0008] In some optional embodiments, the semiconductor material selected for the semiconductor layer is a highly absorbing semiconductor material.

[0009] In some optional embodiments, the semiconductor layer has a thickness of 10 nm to 150 nm.

[0010] In some optional embodiments, the femtosecond laser in pulse train mode emitted by the femtosecond laser is linearly polarized light, the pulse width is adjustable from 750fs to 10ps, the repetition frequency is adjustable from 1KHz to 200KHz, the laser power is adjustable from 0W to 50W, the number of sub-pulses is adjustable from 1 to 10, the central wavelength is 1030nm, and the focal length of the cylindrical lens is 20mm.

[0011] In some optional embodiments, during the processing, the oxidation threshold is determined by the real-time changes of the film surface of the industrial camera structure, and the laser energy of the femtosecond laser is gradually increased by rotating the half-wave plate and adjusting the polarization beam splitter prism until it is slightly higher than the oxidation threshold.

[0012] In some optional embodiments, a femtosecond laser is emitted in a pulse train mode by a femtosecond laser, which passes through an optical half-wave plate, a polarization beam splitter prism, and a cylindrical lens in sequence to form a line spot of 2000 μm × 50 μm to focus vertically on the surface of the structural film, thereby obtaining a micro-nano oxidized periodic structure perpendicular to the laser polarization.

[0013] In some optional embodiments, the physical deposition method is used to prepare a substrate, a metal layer and a semiconductor layer in sequence from bottom to top to form a substrate-metal layer-semiconductor layer bottom-up structural film, including: using a magnetron sputtering coating device to deposit 100nm of metallic copper on a silicon substrate to form a metal layer, and then depositing 40nm of amorphous silicon on the metal layer to form a semiconductor layer, and finally forming a substrate-metal layer-semiconductor layer bottom-up structural film.

[0014] In the above manner, the present application uses a physical deposition method to make a substrate-metal layer-semiconductor layer bottom-up structural film, and then uses a femtosecond laser to directly write the surface of the structural film to obtain a micro-nano oxidation periodic structure. The main part of the micro-nano oxidation periodic structure is a double-layer film structure, including a metal layer and a semiconductor layer, which forms a substrate-metal layer-semiconductor layer bottom-up structural film with the bottom substrate, effectively ensuring the high uniformity and regularity of the processed structure. During laser processing, it is only necessary to build a simple optical path consisting of a femtosecond laser, an optical half-wave plate, a polarization beam splitter prism and a cylindrical lens, without the need for complex structures and expensive equipment. When the formed line spot is focused on the surface of the structural film, the free electrons in the metal layer under the semiconductor layer interact with the laser, increase the semiconductor layer's absorption of laser energy, and reduce the oxidation threshold, thereby forming a micro-nano oxidation periodic structure with high uniformity and regularity. By changing the number of sub-pulses of the femtosecond laser, the period of the micro-nano oxidation periodic structure can be accurately adjusted without complex and cumbersome spatial light modulation, and has a high period tuning sensitivity. In addition, the use of cylindrical lenses to focus the laser to form a linear spot greatly improves processing efficiency. It is very suitable for large-area processing scenarios and has high commercial application value.

[0015] In a second aspect, an embodiment of the present application proposes a computer-readable storage medium storing a computer program, which, when executed by a processor, can implement a method for processing a periodically adjustable micro-nano oxidation periodic structure as described in the first aspect above.

[0016] It can be understood that the beneficial effects of the second aspect mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the related technologies, the drawings required for use in the embodiments of the present application or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a flow chart of a method for processing a periodically adjustable micro-nano oxidation periodic structure provided in one embodiment of the present application;

[0019] Figure 2 It is a schematic structural diagram of a bottom-up structure film of a substrate-metal layer-semiconductor layer provided in one embodiment of the present application;

[0020] Figure 3is a schematic diagram of a light path provided in one embodiment of the present application;

[0021] Figure 4 It is provided in one embodiment of the present application, wherein 100nm of metallic copper is deposited on a silicon substrate as a metal layer, and then 40nm of amorphous silicon is deposited on the metal layer as a semiconductor layer, and finally a scanning electron microscope image and an energy spectrum analysis image of a micro-nano oxidation periodic structure formed after laser processing are used;

[0022] Figure 5 An optical microscope image of a micro-nano periodic oxidation structure formed by depositing 100 nm of copper as a metal layer on a silicon substrate, depositing 40 nm of amorphous silicon as a semiconductor layer on the metal layer, and finally using laser processing is provided in one embodiment of the present application;

[0023] Figure 6 It is a schematic diagram of the corresponding relationship between the period of the micro-nano oxidation periodic structure and the number of sub-pulses of the femtosecond laser provided in one embodiment of the present application. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the embodiments of the present application will be described in detail below in conjunction with the accompanying drawings. In the various embodiments of the present application, many technical details are proposed in order to make the reader better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can also be implemented. The division of the following embodiments is only for the convenience of description, and the specific implementation mode of the present application should not constitute any limitation. The various embodiments can be combined with each other and referenced to each other under the premise of no contradiction.

[0025] An embodiment of the present application proposes a method for processing a periodically adjustable micro-nano oxidation periodic structure. The implementation details of the method for processing a periodically adjustable micro-nano oxidation periodic structure proposed in this embodiment are specifically described below. The following content is only the implementation details provided for the convenience of understanding and is not necessary for the implementation of this solution.

[0026] The specific process of the method for processing a periodically adjustable micro-nano oxidation periodic structure proposed in this embodiment can be as follows: Figure 1 As shown, including:

[0027] Step 101, using a physical deposition method to sequentially prepare a substrate, a metal layer and a semiconductor layer from bottom to top, to form a bottom-up structural film of substrate-metal layer-semiconductor layer.

[0028] In the specific implementation, the first step in preparing the micro-nano periodic structure is to prepare its basic structure. This step requires the use of physical deposition method to prepare the substrate, metal layer and semiconductor layer from bottom to top, so as to form Figure 2 The substrate-metal layer-semiconductor layer structure film from bottom to top is shown.

[0029] In one example, the substrate may be a silicon substrate.

[0030] In one example, the metal material selected for the metal layer is a metal material with balanced reflectivity over the entire visible light band. For example, one or any combination of platinum, gold, silver, titanium, copper, aluminum, and nickel alloys can be deposited on a silicon substrate to form a metal layer, and the thickness of the metal layer must be greater than 50 mm.

[0031] In one example, the semiconductor material selected for the semiconductor layer is a high absorption semiconductor material. For example, amorphous silicon may be deposited on the surface of the metal layer to form a semiconductor layer. The thickness of the semiconductor layer is 10 nm to 150 nm.

[0032] In one example, when preparing the base structure, a magnetron sputtering coating device can be used to deposit 100nm of metallic copper on a silicon substrate to form a metal layer, and then 40nm of amorphous silicon is deposited on the metal layer to form a semiconductor layer, ultimately forming a substrate-metal layer-semiconductor layer structural film from bottom to top.

[0033] Step 102, constructing an optical path consisting of a femtosecond laser, an optical half-wave plate, a polarization beam splitter prism and a cylindrical lens.

[0034] In the specific implementation, after completing the preparation of the structural film (basic structure), the optical path required for laser processing can be built, that is, the optical path composed of a femtosecond laser, an optical half-wave plate, a polarization beam splitter prism and a cylindrical lens.

[0035] In one example, the optical path is constructed as follows Figure 3 As shown, an industrial camera is also set between the structural film and the cylindrical lens to observe the changes on the surface of the structural film.

[0036] In one example, a femtosecond laser is used to emit a femtosecond laser in a pulse train mode, which is specifically linearly polarized light, with a pulse width adjustable from 750fs to 10ps, a repetition frequency adjustable from 1KHz to 200KHz, a laser power adjustable from 0W to 50W, the number of sub-pulses adjustable from 1 to 10, and a central wavelength of 1030nm.

[0037] In one example, the focal length of the cylindrical lens is 20 mm.

[0038] Step 103, using a femtosecond laser to emit a pulse train mode of femtosecond laser, which passes through an optical half-wave plate, a polarization beam splitter prism and a cylindrical lens in sequence to form a line spot focused on the surface of the structural film to obtain a micro-nano oxidation periodic structure.

[0039] In the specific implementation, after completing the preparation of the structural film and the construction of the optical path, a femtosecond laser can be used to emit a femtosecond laser in a pulse train mode. After passing through an optical half-wave plate, a polarization beam splitter prism and a cylindrical lens in sequence, a line spot is formed and focused on the surface of the structural film to obtain a micro-nano oxidation periodic structure.

[0040] In one example, during laser processing, a femtosecond laser (linearly polarized light) in a pulse train mode is emitted by a femtosecond laser with a pulse width of 750fs and a repetition frequency of 25KHz. After the femtosecond laser passes through an optical half-wave plate, a polarization beam splitter prism, and a cylindrical lens in sequence, a 2000μm×50μm line spot is formed to focus vertically on the surface of the structural film, thereby obtaining a micro-nano oxidation periodic structure perpendicular to the laser polarization.

[0041] Considering that a high-quality regular oxidized periodic structure can only be formed when the energy of the incident laser is slightly greater than the oxidation threshold of the material (structural film) surface, during the processing, the real-time changes of the structural film surface are monitored by an industrial camera to determine the oxidation threshold, and the laser energy of the femtosecond laser is gradually increased by rotating the half-wave plate and adjusting the polarization beam splitter prism until it is slightly higher than the oxidation threshold.

[0042] Step 104, by changing the number of sub-pulses of the femtosecond laser, the period of the processed micro-nano oxidation periodic structure is regulated, and the period of the micro-nano oxidation periodic structure increases with the increase in the number of sub-pulses of the femtosecond laser.

[0043] In the specific implementation, when it is necessary to adjust the period time of the micro-nano oxidation periodic structure, it is only necessary to change the number of sub-pulses of the femtosecond laser to achieve the regulation of the period of the processed micro-nano oxidation periodic structure. The period of the micro-nano oxidation periodic structure increases with the increase in the number of sub-pulses of the femtosecond laser, but saturation will occur. Generally speaking, when the number of sub-pulses reaches 6, further increasing the number of sub-pulses will no longer be able to continue to adjust the period of the micro-nano oxidation periodic structure.

[0044] In an example, Figure 4 As shown, through scanning electron microscopy, it can be observed that the formed stripes are composed of nanoparticles, and the stripes are highly uniform and regular. At the same time, using an energy dispersive X-ray spectrometer to analyze the elements after laser irradiation on the surface of the material, it can be clearly seen that there is obvious oxygen element where the stripes are formed, but not at other positions. This further proves that the periodic structure formed is due to nanoparticles formed by oxidation of the material surface, rather than periodic stripes formed by ablation.

[0045] Figure 5 The large-area micro-nano oxidation periodic structure formed under an optical microscope is demonstrated. The micro-nano oxidation periodic structure processed by the 2000μm×50μm line spot formed by the femtosecond laser through the cylindrical lens shows a high degree of regularity and uniformity.

[0046] Figure 6 This is a two-dimensional relationship diagram between the number of sub-pulses of the femtosecond laser emitted by the femtosecond laser and the period of the corresponding micro-nano oxidation periodic structure. The period of the micro-nano oxidation periodic structure can be controlled by simply adjusting the number of sub-pulses of the pulse train of the femtosecond laser. Figure 6 It can be seen that as the number of sub-pulses increases from 1 to 6, the period of the micro-nano oxidation periodic structure also increases accordingly, from 650nm to 850nm. However, such regulation will appear saturated to a certain extent. When the number of sub-pulses reaches 6, further increasing the number of sub-pulses will no longer be able to adjust the period of the micro-nano oxidation periodic structure.

[0047] In this embodiment, a substrate-metal layer-semiconductor layer bottom-up structural film is made by physical deposition method, and then a femtosecond laser is used to directly write the surface of the structural film to obtain a micro-nano oxidation periodic structure. The main part of the micro-nano oxidation periodic structure is a double-layer film structure, including a metal layer and a semiconductor layer. The double-layer film structure and the bottom substrate together form a substrate-metal layer-semiconductor layer bottom-up structural film, which effectively ensures the high uniformity and regularity of the processed structure. During laser processing, it is only necessary to build a simple optical path consisting of a femtosecond laser, an optical half-wave plate, a polarization beam splitter prism and a cylindrical lens, without the need for complex structures and expensive equipment. When the formed line spot is focused on the surface of the structural film, the free electrons in the metal layer under the semiconductor layer will interact with the laser, increase the semiconductor layer's absorption of laser energy, and reduce the oxidation threshold, thereby forming a micro-nano oxidation periodic structure with high uniformity and regularity. By changing the number of sub-pulses of the femtosecond laser, the period of the micro-nano oxidation periodic structure can be accurately adjusted without complex and cumbersome spatial light modulation, and has a high period tuning sensitivity. In addition, the use of cylindrical lenses to focus the laser to form a linear spot greatly improves processing efficiency. It is very suitable for large-area processing scenarios and has high commercial application value.

[0048] The step division of the above methods is only for clear description. When implemented, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this application; adding insignificant modifications to the algorithm or process or introducing insignificant designs without changing the core design of the algorithm and process are all within the scope of protection of this application.

[0049] Another embodiment of the present application proposes a processing system for a periodically adjustable micro-nano oxidation periodic structure. The implementation details of the processing system for a periodically adjustable micro-nano oxidation periodic structure proposed in this embodiment are described in detail below. The following content is only the implementation details provided for the convenience of understanding and is not necessary for the implementation of this example.

[0050] The processing system is mainly composed of a magnetron sputtering coating device, a femtosecond laser, an optical half-wave plate, a polarization beam splitter prism, an industrial camera and a cylindrical lens. In the preparation process, a magnetron sputtering coating device is used, and a physical deposition method is adopted to sequentially prepare a substrate, a metal layer and a semiconductor layer from bottom to top, forming a bottom-up structural film of a substrate-metal layer-semiconductor layer, and a femtosecond laser is used to emit a femtosecond laser in a pulse train mode, and the femtosecond laser passes through an optical half-wave plate, a polarization beam splitter prism and a cylindrical lens in sequence, and the oxidation threshold is determined by the real-time change of the surface of the structural film of the industrial camera, and the laser energy of the femtosecond laser is gradually increased by rotating the half-wave plate and adjusting the polarization beam splitter prism until it is slightly higher than the oxidation threshold, and finally a line spot is formed to focus on the surface of the structural film, and a micro-nano oxidation periodic structure is obtained, and the processing of the micro-nano oxidation periodic structure is completed.

[0051] If the period of the micro-nano oxidation periodic structure needs to be regulated, the number of sub-pulses of the femtosecond laser needs to be changed. The period of the micro-nano oxidation periodic structure increases with the increase in the number of sub-pulses of the femtosecond laser, but saturation will occur.

[0052] It is worth mentioning that all modules involved in this embodiment are logic modules. In practical applications, a logic unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. In addition, in order to highlight the innovative part of this application, this embodiment does not introduce units that are not closely related to solving the technical problems proposed by this application, but this does not mean that there are no other units in this embodiment.

[0053] It is not difficult to find that this embodiment is a system embodiment corresponding to the above method embodiment, and this embodiment can be implemented in conjunction with the above method embodiment. The relevant technical details and technical effects mentioned in the above embodiments are still valid in this embodiment, and in order to reduce repetition, they are not repeated here. Accordingly, the relevant technical details mentioned in this embodiment can also be applied in the above embodiments.

[0054] Another embodiment of the present application provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it can implement a method for processing a periodically adjustable micro-nano oxidation periodic structure as described in the above method embodiments.

[0055] That is, those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including a number of instructions to enable a device (which can be a single-chip microcomputer, chip, etc.) or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, ROM (Read-Only Memory), RAM (Random Access Memory), disk or optical disk and other media that can store program codes.

[0056] Those skilled in the art will appreciate that the above embodiments are specific embodiments for implementing the present application, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present application.

Claims

1. A method for processing a periodically adjustable micro-nano oxidation periodic structure, characterized in that: include: A substrate, a metal layer and a semiconductor layer are sequentially prepared from bottom to top using a physical deposition method to form a bottom-up structural film of substrate-metal layer-semiconductor layer; Build an optical path consisting of a femtosecond laser, an optical half-wave plate, a polarization beam splitter prism, and a cylindrical lens; A femtosecond laser is used to emit a pulse train mode of femtosecond laser, which passes through an optical half-wave plate, a polarization beam splitter prism and a cylindrical lens in sequence to form a line spot focused on the surface of the structured film to obtain a micro-nano periodic oxidation structure. By changing the number of sub-pulses of the femtosecond laser, the period of the processed micro-nano oxidation periodic structure can be regulated, and the period of the micro-nano oxidation periodic structure increases with the increase in the number of sub-pulses of the femtosecond laser.

2. The method for processing a periodically adjustable micro-nano oxidation periodic structure according to claim 1, characterized in that: The metal material selected for the metal layer is one of platinum, gold, silver, titanium, copper, aluminum, nickel or an alloy of any combination.

3. The method for processing a periodically adjustable micro-nano oxidation periodic structure according to claim 2, characterized in that: The thickness of the metal layer is greater than 50 mm.

4. The method for processing a periodically adjustable micro-nano oxidation periodic structure according to claim 1, characterized in that: The semiconductor material selected for the semiconductor layer is a highly absorbing semiconductor material.

5. The method for processing a periodically adjustable micro-nano oxidation periodic structure according to claim 4, characterized in that: The thickness of the semiconductor layer is 10 nm to 150 nm.

6. The method for processing a periodically adjustable micro-nano oxidation periodic structure according to claim 1, characterized in that: The femtosecond laser in pulse train mode emitted by the femtosecond laser is linearly polarized light, with a pulse width adjustable from 750fs to 10ps, a repetition frequency adjustable from 1KHz to 200KHz, a laser power adjustable from 0W to 50W, an adjustable number of sub-pulses from 1 to 10, a central wavelength of 1030nm, and a focal length of the cylindrical lens of 20mm.

7. The method for processing a periodically adjustable micro-nano oxidation periodic structure according to claim 6, characterized in that: During the processing, the real-time changes on the surface of the film structured by an industrial camera are used to determine the oxidation threshold, and the laser energy of the femtosecond laser is gradually increased by rotating the half-wave plate and adjusting the polarization beam splitter prism until it is slightly above the oxidation threshold.

8. The method for processing a periodically adjustable micro-nano oxidation periodic structure according to claim 7, characterized in that: A femtosecond laser is used to emit a pulse train mode of femtosecond laser, which passes through an optical half-wave plate, a polarization beam splitter prism and a cylindrical lens in sequence to form a 2000μm×50μm line spot that is vertically focused on the surface of the structural film to obtain a micro-nano oxidized periodic structure perpendicular to the laser polarization.

9. A method for processing a periodically adjustable micro-nano oxidation periodic structure according to any one of claims 1 to 8, characterized in that: The substrate, metal layer and semiconductor layer are prepared sequentially from bottom to top using a physical deposition method to form a substrate-metal layer-semiconductor layer bottom-up structure film, including: Using a magnetron sputtering coating device, 100nm of metallic copper is deposited on a silicon substrate to form a metal layer, and then 40nm of amorphous silicon is deposited on the metal layer to form a semiconductor layer, ultimately forming a substrate-metal layer-semiconductor layer bottom-up structural film.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, it can implement a method for processing a periodically adjustable micro-nano oxidation periodic structure as claimed in any one of claims 1 to 9.

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