Method for preparing flexible film with adjustable wrinkle structure under high temperature conditions and its application
By using mica substrate and magnetron sputtering technology to grow and pre-stretch the film at high temperature, the problem of preparing flexible magnetic films at high temperatures in the prior art is solved, and a flexible film preparation with high growth temperature and stable performance is achieved at high temperatures. and the formation of large-area regular fold structures.
Patent Information
- Application Number
- CN202111391287.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-11-23
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2041-11-23
AI Technical Summary
The prior art is difficult to prepare flexible magnetic films with regular wrinkle structures under conditions of growth at high temperatures and mismatch between lattice parameters, and it is impossible to prepare and maintain properties of large-area flexible films.
The film is grown by using mica substrate for mechanical dissociation and magnetron sputtering technology, and the pre-stretching and wrinkle structure formation is achieved through tensile molds. The film is grown by direct transfer method, avoiding the requirement of sacrificial layer and high lattice matching. , using high temperature resistant mica substrate and magnetron sputtering technology.
A flexible film preparation with high growth temperature and stable performance at high temperatures is realized, and a relatively large area of regular wavy wrinkle structure film can be prepared, and the wavelength and amplitude of the wrinkle structure are regulated by regulating thickness and annealing, so that the film properties are kept intact.
Smart Images
Figure CN114351090B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of electronic technology, and in particular to a method and application for preparing a flexible film with an adjustable wrinkle structure under high temperature conditions, so as to prepare a flexible film with a high growth temperature and a regular wrinkle structure. Background Art
[0002] With the rise of flexible electronics, wearable and implantable technologies, there is a demand for flexible sensors. Magnetic sensors, as a very important type of sensor, also face the problem of flexibility. To make magnetic sensors flexible, it is necessary to make the magnetic film material of its functional layer flexible, and making the film stretchable by making a wrinkled structure is the main method to achieve flexibility.
[0003] At present, there are three main ways to prepare flexible films with wrinkled structures: (1) directly growing a film on a pre-stretched flexible substrate and then releasing the pre-stretching to obtain a wrinkled structure; (2) transferring the film to prepare a wrinkled structure by dissolving a sacrificial layer; (3) artificially designing a wrinkled structure. However, the above methods are only applicable to the preparation of flexible films grown at room temperature, and are not applicable to the preparation of flexible films grown at high temperatures whose lattice parameters do not match those of the sacrificial layer. Summary of the invention
[0004] In order to overcome the defects of the prior art, the present invention provides a film flexibility method suitable for growth at high temperature and with controllable wrinkle structure.
[0005] The present invention provides a method for preparing a flexible film with an adjustable wrinkle structure under high temperature conditions, comprising the following steps:
[0006] S1. Mechanically dissociate the mica substrate, and after the new surface is dissociated, use silver glue to stick the back of the mica substrate to the surface of the high-temperature sample holder, and place it on a heating table to dry;
[0007] S2. The dried high-temperature sample holder is sent into a magnetron sputtering chamber, and the mica substrate is magnetron sputtered to grow a thin film. The magnetron sputtering includes the following steps: vacuuming, annealing the mica substrate, adjusting the temperature to the sample growth temperature, passing argon gas, pre-sputtering, formally growing a thin film, annealing the thin film, cooling and sampling;
[0008] S3. Pre-stretching the flexible substrate by stretching the die;
[0009] S4. Lay the mica substrate with the film grown on one side onto the pre-stretched flexible substrate, put it into an oven for heating, take it out for cooling, and then mechanically peel off the mica substrate, control the stretching mold to release the pre-stretching, and obtain a flexible film with a pleated structure.
[0010] Compared with the prior art, the method for preparing a flexible film with an adjustable wrinkle structure under high temperature conditions of the present invention has the following advantages: (1) The present invention directly grows the film on the surface of a mica substrate by a direct transfer method. The method is simple, does not require high lattice matching, and does not require the preparation of a sacrificial layer; (2) The present invention adopts a mica substrate that is resistant to high temperatures of 1100°C, and can prepare a flexible film with a high growth temperature and stable performance. The growth temperature of the film is no longer limited by the flexible substrate; (3) Using the method of the present invention, a flexible film with a larger area can be prepared, and the film can remain intact after transfer, and the properties are basically the same as before transfer; (4) The flexible film prepared by the present invention has a regular wavy wrinkle structure. The wavelength and amplitude of the wavy wrinkle structure can be controlled by changing the film thickness, the cooling method after film annealing, and the pre-stretching ratio of the flexible substrate.
[0011] Preferably, the mechanical dissociation of the mica substrate in step S1 is carried out in a water bath. Since the mica substrate has a book-shaped structure, it can be peeled and completely cleaved. In order to produce a new surface with good flatness, the knife edge used in the dissociation should be kept parallel to the mica substrate.
[0012] Furthermore, in step S1, the center of the high temperature sample holder is a 10 mm×10 mm SiC block, and the mica substrate is pasted on the SiC surface with silver glue.
[0013] Furthermore, during magnetron sputtering in step S2, the back of SiC is heated by laser, and the good thermal conductivity of SiC and silver paste is utilized to keep the mica substrate at a high temperature during the film growth process.
[0014] Furthermore, the initial vacuum degree of the magnetron sputtering chamber in step S2 is 5×10 -8 torr~5×10 -9 torr, the heating source for mica substrate annealing and thin film annealing is laser heating, the substrate annealing temperature is 500℃~700℃, the thin film growth temperature is 500℃~600℃, the thin film annealing temperature is 600℃~800℃, the target material and the substrate are sputtered at an angle of 30°~60° during thin film growth, the high-temperature sample holder rotates at 10 rpm during thin film growth, and the high-temperature sample holder rotates at 1 rpm during thin film annealing, and the cooling rate is 0.2℃ / sec~0.6℃ / sec.
[0015] Furthermore, the cooling method in step S4 includes water cooling and air cooling.
[0016] Preferably, the pre-stretching in step S3 is performed by clamping both ends of the flexible substrate.
[0017] Furthermore, the mechanical stripping of the mica substrate in step S4 is to mechanically strip the mica substrate on the back of the film using an adhesive tape.
[0018] Furthermore, releasing the pre-stretching in step S4 refers to keeping one end of the flexible substrate fixed, slowly releasing the other end of the flexible substrate, and then removing the flexible film.
[0019] The present invention also provides an application of a flexible film with an adjustable corrugated structure in the field of electronics, that is, a method for preparing a flexible film with an adjustable corrugated structure under high temperature conditions is applied in the field of electronics. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 A schematic diagram of the transfer process for preparing a flexible FeRh film with an adjustable wrinkle structure according to the present invention;
[0021] Figure 2 The MT curve diagram of the flexible FeRh film with adjustable wrinkle structure prepared by the present invention;
[0022] Figure 3 Atomic force microscope surface morphology of the flexible FeRh film with an adjustable wrinkle structure prepared in the present invention. DETAILED DESCRIPTION
[0023] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.
[0024] Embodiment 1
[0025] The method for preparing a flexible FeRh film with an adjustable wrinkle structure under high temperature conditions comprises the following steps:
[0026] S1. Under an optical microscope, use a surgical blade to mechanically dissociate an artificial fluorine crystal mica substrate of 5mm×5mm×0.2mm in a water bath. The blade used during dissociation should be kept parallel to the mica substrate. After dissociating the new surface, use a nitrogen gun to blow dry the moisture on the surface of the mica substrate. Then use silver glue to stick the reverse side of the mica substrate to the surface of a 10mm×10mm SiC block in the center of the high-temperature sample holder. The newly dissociated surface faces upward for growing a thin film. Dry it on a heating table at a drying temperature of 120°C. After drying, use a nitrogen gun to clean the substrate surface again, and ensure that the mica substrate is firmly adhered.
[0027] S2. Place the dried high-temperature sample holder into the magnetron sputtering chamber and evacuate the magnetron sputtering chamber to a vacuum degree of 8×10 -8torr, and then turn on the laser heating source to heat the back of SiC. Using the good thermal conductivity of SiC and silver glue, the mica substrate is heated and maintained at a high temperature of 600℃ for annealing. After the annealing of the mica substrate is completed, the laser is adjusted to control the temperature of the mica substrate to be 550℃ for film growth. The argon valve is opened to introduce argon gas, and the power is turned on for pre-sputtering. During sputtering, the FeRh (iron rhodium) target is set at a 45° tilt with the mica substrate and the high-temperature sample holder is kept rotating at 10 rpm to formally grow the FeRh film. The gas flow rate and molecular pump speed are adjusted to keep the cavity pressure at 1.4 -2 torr; after the growth of the FeRh film is completed, the temperature of the mica substrate is adjusted to 700°C and the high-temperature sample holder is kept rotating at 1 rpm to anneal the FeRh film; after the annealing of the FeRh film is completed, the temperature is cooled to room temperature at a cooling rate of 0.4°C / s, and finally the FeRh film is sampled;
[0028] S3, by stretching the mold, clamping the two ends of the PDMS (polydimethylsiloxane) flexible substrate and pre-stretching it, so that the PDMS flexible substrate obtains pre-strain (such as Figure 1 shown);
[0029] S4. The mica substrate with the FeRh film grown on one side is attached to the pre-stretched PDMS flexible substrate, placed in an oven (OVEN) for heating and then taken out for cooling, and then the mica substrate and the FeRh film are mechanically peeled off using tape, the stretching mold is controlled to keep one end of the flexible substrate fixed, the other end of the flexible substrate is slowly released, and then the flexible FeRh film is removed to obtain a flexible FeRh film with a pleated structure.
[0030] In this embodiment, the FeRh film is directly grown on the surface of the artificial fluorphlogopite substrate by a direct transfer method. The method is simple, does not require high lattice matching, and does not require the preparation of a sacrificial layer. Fluorphlogopite is a silicate artificial mica crystal, which is a mica crystal melted in a platinum crucible at a high temperature of 1500°C under strict process conditions and material ratios. Its chemical formula is KMg3(AlSi3O 10)F2, does not contain (OH)ˉ, and uses Fˉ (fluorine) to replace the (OH)ˉ hydroxyl group, which has excellent electrical insulation properties and high temperature resistance, and can withstand high temperatures of 1100°C; and the fluorphlogopite mica has a book-shaped structure, can be peeled, and completely cleaved, and the thinnest can be peeled to 0.02 mm; the flatness is very good, reaching the atomic level; it is not easy to deform, can withstand greater pressure, and has higher tensile strength and compressive strength; it does not age, is not easy to break, and is not easy to absorb impurities; the present invention uses a mica substrate that is resistant to high temperatures of 1100°C to prepare a flexible film with high growth temperature and stable performance, and the growth temperature of the film is no longer limited by the flexible substrate. Using the method of the present invention, a flexible film of a larger area can be prepared, and the film can remain intact after transfer, and the properties are basically the same as before transfer; the flexible film prepared by the present invention is a regular wavy pleated structure, and the wavelength and amplitude of the wavy pleated structure can be adjusted by changing the film thickness, the cooling method after film annealing, and the pre-stretching ratio of the flexible substrate.
[0031] Test Example 1
[0032] The flexible FeRh film obtained in Example 1 was tested to obtain the MT curve, as shown in Figure 2 As shown, the flexible FeRh film exhibits a first-order phase transition near room temperature, which meets the usage requirements and realizes the flexibility of the film that needs to be grown at high temperature.
[0033] Test Example 2
[0034] Different types of flexible FeRh films were prepared according to the method of Example 1 to examine the flexibility effects of different cooling methods on FeRh films of different thicknesses in step S4, and the microscopic morphologies of the above-mentioned different types of flexible FeRh films were observed to obtain atomic force microscope surface morphology images. Figure 3 As shown, the wrinkle morphology of the FeRh film is a regular wave. Specifically, Figure 3-1 and Figure 3 -4 shows that the cooling method has a regulatory effect on the specific wrinkle morphology of the flexible FeRh film. The faster the cooling speed, the smaller the wavelength and amplitude of the wavy wrinkle morphology; Figure 3-1 , Figure 3-2 and Figure 3-3 It shows that the thicker the flexible FeRh film is, the larger the wavelength and amplitude of the wavy wrinkle morphology is. Figure 3 -4. Figure 3 -5 and Figure 3 -6 also shows this trend. In addition, the larger the pre-stretching ratio, the larger the wavelength and amplitude of the wavy wrinkle morphology.
[0035] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.
Claims
1. A method for preparing a flexible film with an adjustable wrinkle structure under high temperature conditions, comprising the following steps: S1. Under an optical microscope, use a surgical blade to mechanically dissociate an artificial fluorphlogopite mica substrate of 5mm×5mm×0.2mm in a water bath. The blade used during dissociation should be kept parallel to the mica substrate. After dissociating the new surface, use a nitrogen gun to blow dry the moisture on the surface of the mica substrate. Then use silver glue to stick the reverse side of the mica substrate to the surface of a 10mm×10mm SiC block in the center of the high-temperature sample holder. The newly dissociated surface faces upward for growing a thin film. Dry it on a heating table at a drying temperature of 120°C. After drying, use a nitrogen gun to clean the substrate surface again, and ensure that the mica substrate is firmly adhered. S2. Place the dried high-temperature sample holder into the magnetron sputtering chamber and evacuate the magnetron sputtering chamber to a vacuum degree of 8×10 -8 torr, and then turn on the laser heating source to heat the back of SiC. Using the good thermal conductivity of SiC and silver glue, the mica substrate is heated and maintained at a high temperature of 600℃ for annealing. After the mica substrate is annealed, the laser is adjusted to control the temperature of the mica substrate to be 550℃ for film growth. The argon valve is opened to introduce argon gas, and the power is turned on for pre-sputtering. During sputtering, the FeRh target and the mica substrate are kept tilted at 45° and the high-temperature sample holder is kept rotating at 10 rpm. The FeRh film is formally grown, and the gas flow rate and molecular pump speed are adjusted to keep the cavity pressure at 1.4 -2 torr; after the growth of the FeRh film is completed, the temperature of the mica substrate is adjusted to 700°C and the high-temperature sample holder is kept rotating at 1 rpm to anneal the FeRh film; after the annealing of the FeRh film is completed, the temperature is cooled to room temperature at a cooling rate of 0.4°C / s, and finally the FeRh film is sampled; S3, clamping the two ends of the PDMS flexible substrate by stretching the mold and then pre-stretching it, so that the PDMS flexible substrate obtains pre-strain; S4. Lay the mica substrate with one side of the FeRh film grown on the pre-stretched PDMS flexible substrate, put it into an oven for heating, and then take it out for cooling. The cooling method is water cooling or air cooling. The cooling method has a regulating effect on the wrinkle morphology of the flexible FeRh film. The faster the cooling speed, the smaller the wavelength and amplitude of the wavy wrinkle morphology. Then use tape to mechanically peel off the mica substrate and the FeRh film, control the stretching mold to keep one end of the flexible substrate fixed, slowly release the other end of the flexible substrate and then remove the flexible FeRh film to obtain a wrinkle structure flexible FeRh film.
2. Application of a flexible film with an adjustable pleated structure in the field of electronics, characterized in that: Flexible film with adjustable wrinkle structure Prepared according to the preparation method of claim 1.