Preparation method of film with composite microstructure surface state, film and application

Abstract

The invention discloses a preparation method of a film with a composite microstructure surface state, the film and application. The preparation method comprises the following steps: pretreating a substrate; the pretreated substrate is directly subjected to microstructure laser processing or thin film deposition; and carrying out thin film deposition on the substrate subjected to the laser processing of the microstructure, and carrying out laser processing of the microstructure on the substrate directly subjected to the thin film deposition, so that two different microstructures are formed. Two microstructures with different properties are formed on the surface of the component through the magnetron sputtering technology and the laser machining technology, the two technologies are combined to be suitable for various materials, machining can be conducted on the surfaces of the different materials so as to reduce the secondary electron yield, machining is not limited to specific material types, and the application range is widened.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of micro-structured surface film preparation, and particularly relates to a film preparation method with a composite micro-structured surface state, a film and application. BACKGROUND

[0002] The micro-discharge effect of a space high-power microwave component is the first problem to be solved. The space micro-discharge effect, also known as the secondary electron multiplication effect, refers to a resonant discharge phenomenon generated when a high-power microwave component transmits a high-power microwave signal at a pressure of 1×10 -3 Pa or lower. The micro-discharge effect is a very important factor affecting the reliability of aerospace electronic equipment. With the rapid development of space electronic equipment, how to effectively suppress the secondary electron multiplication has become a bottleneck problem restricting the development of space communication technology. The secondary electron multiplication effect can cause the standing wave ratio of a microwave transmission system to gradually increase, the reflected power to increase, and the noise level to rise, thereby causing the high-power microwave system to not work normally. The micro-discharge can also cause fluctuations in cavity tuning, parameter coupling, waveguide loss and phase constant, produce harmonics to cause out-of-band interference and passive intermodulation products, and cause erosion on the surface of the component.

[0003] At present, most of the suppression methods for the secondary electron emission are to change the surface topography to reduce the SEY (Secondary Electron Yield), thereby realizing the suppression of the micro-discharge effect. In recent years, the European Space Agency has continuously carried out in-depth and systematic research on the control technology of the surface topography in multiple projects. The main research content is various surface treatment technologies capable of effectively suppressing the secondary electron multiplication effect, including anti-electron multiplication coating, chemical corrosion, and trench structure construction.

[0004] In recent years, people have proposed plating a thin film of a material with a low secondary electron emission coefficient on the surface of a material to suppress the secondary electron emission. Compared with changing the surface topography of the material, the plating method has a relatively simple process and a small influence on the device itself. However, the surface defect structure cannot be ignored for its excellent suppression effect on the secondary electron emission. Compared with other SEY reduction technologies, it is relatively easy to use laser etching technology to prepare a micro-nano structure on the surface of the material, and the laser etching has the advantages of low environmental requirements and stable microstructure. However, the difference in the thermal expansion coefficient or chemical properties between the plating material and the substrate may cause interface stress and reduce the adhesion, and the plating film is prone to peeling after long-term use. Moreover, when the plating film is exposed to air or a complex environment, the SEY may rise due to oxidation, adsorption of gas or pollutants (such as water vapor and organic matter). At the same time, the surface defect structure formed is directly exposed on the surface and is prone to fracture or collapse in mechanical vibration, particle bombardment or daily maintenance, thereby causing the SEY suppression to fail. SUMMARY

[0005] The object of the present invention is to provide a method for preparing a film having a composite microstructure surface state, a film and its application to solve the above problems.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A method for preparing a thin film having a composite microstructure surface state, comprising: Pre-treating the substrate; Directly laser processing microstructures or directly performing thin film deposition on the pretreated substrate; The substrate that has been laser processed for microstructure is subjected to thin film deposition and then the substrate that has been directly subjected to thin film deposition is subjected to laser processing for microstructure, both of which form two different microstructures.

[0007] Furthermore, the pre-processing substrate comprises: The surface of one substrate was cleaned with isopropyl alcohol and deionized water and then dried with N2.

[0008] Furthermore, the laser processing of the microstructure directly on the pre-treated substrate includes: Microstructures are etched on the substrate surface by laser processing.

[0009] Furthermore, the step of directly depositing a thin film on the treated substrate comprises: The substrate fixed on the tray is sent into the chamber, and after the target material is installed, the chamber is vacuumed; inert gas is passed into the chamber, and pre-sputtering is performed without opening the baffle to keep the target surface clean; after pre-sputtering, the baffle is opened, sputtering officially begins, and the microstructure continues to grow.

[0010] Furthermore, the substrate was fixed on the tray of magnetron sputtering with Kapton tape, and then placed into the chamber. The C target was placed on the DC target and the Ag target was placed on the pulse target. The sputtering chamber was then closed and vacuumed to 5*10 -4 Below Pa.

[0011] Furthermore, argon gas was introduced into the chamber, the DC target and pulse target powers were set, and pre-sputtering was performed for 5 min without opening the baffle.

[0012] Furthermore, the argon pressure is 1-1.5 Pa, and the argon flow rate is 35-55 sccm.

[0013] Furthermore, the DC target power is 150 W, the pulse target power is 35~75 W, the baffle is opened, and sputtering officially begins, and the growth time continues for 30~60 minutes; the substrate on which the thin film is directly deposited is then laser processed into a microstructure, including: etching a microstructure on the surface of the component with the thin film deposited by laser processing.

[0014] A thin film prepared based on the method for preparing a thin film containing a composite microstructure surface state.

[0015] An application of a thin film for inhibiting secondary electron emission.

[0016] Compared with the prior art, the present application has the following technical effects: In the present application, two different microstructures are formed on the surface of the component by using two processes of magnetron sputtering and laser processing. The combination of the two processes is suitable for a variety of materials and can process the surfaces of different materials to reduce the secondary electron yield without being limited to specific material types, thereby increasing the application range. In terms of stability, the laser composite processing of the thin film may form a more stable structure on the surface of the component, which is not easily affected by the external environment, so that the effect of reducing the secondary electron yield is more persistent. In addition, from the synergistic effect, the combination of multiple ways may have an effect of 1+1>2 because different ways have different mechanisms and different energy ranges for reducing the yield, so that the overall reduction effect is more significant. From the long-term development, the combination of multiple ways also provides more excellent ideas for further exploring the optimization of the reduction yield technology in the future. Subsequent researchers can continuously tap the potential of improving the effect by adjusting the combination of different processing methods, parameters, etc. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is an ideal schematic diagram of a thin film structure.

[0018] Figure 2 is an ideal schematic diagram of laser-processed microstructure.

[0019] Figure 3 is an SEM diagram of the surface of the component after composite processing.

[0020] Figure 4 is the yield of secondary electrons escaping from the surface of the material. DETAILED DESCRIPTION

[0021] The present application is further described below in conjunction with the accompanying drawings: Real-time stream 1, the present application provides a method for preparing a thin film containing a composite microstructure surface state, comprising: pretreating a substrate; directly laser-processing microstructure on the pretreated substrate or directly depositing a thin film on the pretreated substrate; depositing a thin film on the substrate subjected to laser-processing microstructure, and laser-processing microstructure on the substrate directly deposited with a thin film, both of which form two different microstructures.

[0022] This invention combines thin films with microstructures to reduce the secondary electron emission coefficient of components. High-quality, low-secondary-emission C-Ag composite films are produced using magnetron sputtering, and surface microstructures are created using fiber lasers. Two possible sequences are available: laser processing followed by thin film deposition, or thin film deposition followed by laser processing.

[0023] Magnetron sputtering and laser processing are used to form two microstructures with different properties on the surface of the component. The combination of the two processes is applicable to a variety of materials. They can be used to process the surfaces of different materials to reduce the secondary electron yield, and are not limited to specific material types, thereby expanding the scope of application.

[0024] In Example 2, the present invention provides a method for preparing a film having a composite microstructure surface state, specifically comprising: Laser processing followed by thin film deposition: Step 1: Cleaning: clean the surface of a substrate using isopropyl alcohol and deionized water, and blow dry with N2.

[0025] Step 2: Set the laser processor power to 30 W and etch a microstructure on the surface of the component (the microstructure is a cylindrical hole with a depth of 400 μm, a diameter of 175 μm, and a hole spacing of 200 μm).

[0026] Step 3: Use Kapton tape to place the substrate on the tray of magnetron sputtering, put it into the chamber, and install the C target on the DC target and the Ag target on the pulse target. Then close the sputtering chamber and perform vacuum work. Vacuum to 5*10 -4 Below Pa.

[0027] Step 4: Supply argon gas into the chamber with an argon pressure of 1.5 Pa and an argon flow rate of 55 sccm. Set the DC target power to 150 W and the pulsed target power to 75 W. Perform pre-sputtering for 5 minutes without opening the baffle to keep the target surface clean.

[0028] Step 5: Open the baffle and officially start sputtering, and continue the growth time for 1 hour.

[0029] Thin film deposition first, laser processing later Step 1: Cleaning: clean the surface of a substrate using isopropyl alcohol and deionized water, and blow dry with N2.

[0030] Step 2: Use Kapton tape to place the substrate on the tray of magnetron sputtering, put it into the chamber, and install the C target on the DC target and the Ag target on the pulse target. Then close the sputtering chamber and perform vacuum work. Vacuum to 5*10 -4 Below Pa.

[0031] Step 3: Supply argon gas into the chamber with an argon pressure of 1.5 Pa and an argon flow rate of 55 sccm. Set the DC target power to 150 W and the pulsed target power to 75 W. Perform pre-sputtering for 5 minutes without opening the baffle to keep the target surface clean.

[0032] Step 4: Open the baffle and officially start sputtering, and continue the growth time for 1 hour.

[0033] Step 5: Set the laser processor power to 30 W and etch a microstructure on the surface of the component with the thin film deposited (the microstructure is a cylindrical hole with a depth of 400 μm, a diameter of 175 μm, and a hole spacing of 200 μm).

[0034] In Example 3, the present invention provides a film, which is prepared by using a method for preparing a film having a composite microstructure surface state.

[0035] In embodiment 4, the thin film is used to suppress secondary electron emission.

[0036] According to the existing literature, the secondary electron emission coefficient σ of the unprocessed component surface max =2.522. After surface modification using the micro-nano processing and coating process mentioned in this patent, the secondary electron emission coefficient σ max Significantly reduced. Among them, the parts processed by laser alone max =0.57, which is similar to the value of micro-nano processing followed by coating, with a decrease of about 77.6%; while the value of the sample coated first and then micro-nano processing dropped to 0.46, a decrease of 81.7%.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a thin film having a composite microstructure surface state, characterized in that: include: Pre-treating the substrate; Directly laser processing microstructures or directly performing thin film deposition on the pretreated substrate; The substrate that has been laser processed for microstructure is subjected to thin film deposition and then the substrate that has been directly subjected to thin film deposition is subjected to laser processing for microstructure, both of which form two different microstructures.

2. The method for preparing a thin film having a composite microstructure surface state according to claim 1, characterized in that: The pre-treated substrate comprises: The surface of one substrate was cleaned with isopropyl alcohol and deionized water and then dried with N2.

3. The method for preparing a thin film having a composite microstructure surface state according to claim 1, characterized in that: The method of directly laser processing a microstructure on the pretreated substrate comprises: Microstructures are etched on the substrate surface by laser processing.

4. The method for preparing a thin film having a composite microstructure surface state according to claim 1, wherein: The method of directly depositing a thin film on the treated substrate comprises: The substrate fixed on the tray is sent into the chamber, and after the target material is installed, the chamber is vacuumed; inert gas is passed into the chamber, and pre-sputtering is performed without opening the baffle to keep the target surface clean; after pre-sputtering, the baffle is opened, sputtering officially begins, and the microstructure continues to grow.

5. The method for preparing a thin film having a composite microstructure surface state according to claim 4, wherein: Use Kapton tape to fix the substrate on the tray of magnetron sputtering, put it into the chamber, and install the C target on the DC target and the Ag target on the pulse target. Then close the sputtering chamber and perform vacuum work. Vacuum to 5*10 -4 Below Pa.

6. The method for preparing a thin film having a composite microstructure surface state according to claim 4, wherein: Argon gas was introduced into the chamber, the DC target and pulse target powers were set, and pre-sputtering was performed for 5 min without opening the shutter.

7. The method for preparing a thin film having a composite microstructure surface state according to claim 4, wherein: The argon pressure is 1~1.5 Pa, and the argon flow rate is 35~55 sccm.

8. The method for preparing a thin film having a composite microstructure surface state according to claim 4, wherein: The DC target power is 150 W, the pulse target power is 35-75 W, the shutter is opened, and sputtering officially begins. The growth time is 30-60 minutes. The substrate directly subjected to thin film deposition is then laser processed into a microstructure, comprising: etching a microstructure on the surface of the component on which the thin film is deposited by laser processing.

9. A film, characterized in that The film is prepared based on the method for preparing a film containing a composite microstructure surface state according to any one of claims 1 to 8.

10. The use of a film according to claim 9, characterized in that: Used to suppress secondary electron emission.

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