Deposition device and deposition method for preparing layered wrinkle structure and obtained wrinkle structure

Abstract

The invention discloses a movable mask device for preparing a layered wrinkle structure, a deposition method and the obtained wrinkle structure. The device comprises a chassis, a substrate mounting module, a mask movement assembly, a replaceable mask library and a control module. The mask motion assembly is composed of a plurality of linear motion driving modules and a plurality of rotary driving modules, and can realize programmable compound motion of the mask in translation and rotation directions; the mask library is detachably installed in the mask frame, and spatial selective control over the deposition area is achieved through adjustment and control over the motion trail and the retention time. According to the method, by selecting different mask patterns and setting a mask movement track and deposition time, metal is deposited on the surface of a flexible substrate to construct adjustable area thickness distribution; then, in the liquid polymer curing or substrate cooling process, due to the spatial gradient of the rigid layer thickness and the stress, non-uniform strain occurs on the interface, so that a layered wrinkle microstructure with directivity and hierarchy is spontaneously formed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of flexible electronics, micro-nano manufacturing and thin film deposition control, and particularly relates to a regionally selective deposition device based on a movable mask, a method for constructing a layered wrinkle structure thin film and a wrinkle structure obtained , belonging to the technical field of flexible electronics manufacturing, surface microstructure engineering and programmable materials. BACKGROUND

[0002] Flexible electronic devices, smart electronic skin, stretchable sensors and tunable optical elements have an increasing demand for flexible thin films with directionality, layering and tunable structures. Wrinkle structure materials are widely used in strain sensing, surface coding, friction control, and electrical stability enhancement due to their good mechanical sensitivity, optical modulation ability and multi-scale response characteristics. In particular, when the wrinkle structure has multi-level stacking, periodic gradient or regional directional difference, its application value in flexible sensors, smart interfaces, photonics and encrypted displays is more significant.

[0003] Currently, the preparation of controllable wrinkle structures still mainly relies on overall stress induction methods, such as pre-stretching-release method, thermal expansion / cooling contraction driving method, solvent induction method and multi-layer film interface mismatch method. For example, CN103789741A forms self-induced wrinkles by heating or stretching the polymer thin film as a whole; CN114496398B realizes the corrugated structure by depositing metal on PDMS and stretching mechanically; CN115124751B utilizes the difference in thermal expansion coefficients of different materials to generate spontaneous stress during the cooling process, forming a wrinkle microstructure.

[0004] The above methods can form wrinkle structures, but have the following significant limitations: (1) The preparation process relies on overall external field (heating / stretching), making it difficult to achieve controllable wrinkles in local regions; (2) The direction, period and level of the wrinkles are difficult to program and control through design; (3) It is impossible to realize multi-level structures on curved or complex substrates; (4) The cost is high, the repeatability is poor, and it is difficult to realize spatially controllable patterning and functionalization in large-area preparation.

[0005] In the field of display devices and OLED preparation, existing technologies have disclosed schemes for moving the mask or producing relative displacement with the substrate during the deposition process, for realizing the patterned deposition of thin films such as electrode layers and light-emitting layers on rigid or semi-rigid planar substrates. Although such technologies introduce a movable mask, they mainly have the following deficiencies: First, mask motion is usually only used for scanning or alignment, lacking a coordinated control mechanism with substrate rotation, making it difficult to construct thickness and stress gradients with preset rules on curved surfaces or flexible substrates with primary microstructures. Secondly, the existing movable mask devices mainly aim to obtain stable patterned films, but do not address the construction needs of layered wrinkled structures. They have not disclosed a technical solution for forming directional and layered wrinkled films by coupling mask movement, substrate rotation and multilayer liquid-solid structure. Third, the deposited objects are mostly solidified single-layer or multi-layer thin film structures. No liquid or semi-solidified polymer intermediate layer is introduced on the surface of the flexible substrate, nor is the volume shrinkage difference and thermal expansion coefficient difference in the subsequent curing or cooling process used to actively design and control the stress field. Summary of the Invention

[0006] To address the technical problems existing in the prior art, the present invention provides a deposition apparatus, deposition method, and obtained folded structure for the preparation of layered folded structures. By programmably controlling the position, orientation, and exposure time of the mask during the deposition process, a rigid layer with regional thickness differences is constructed on the surface of a flexible multilayer substrate, thereby inducing the formation of directional and hierarchical layered folded microstructures during subsequent curing or cooling.

[0007] To achieve the above objectives, the specific technical solution adopted by the present invention is as follows: The present invention provides a deposition system for fabricating layered folded structures, comprising a chassis, a substrate mounting module, a mask motion assembly, a mask, a deposition module, and a control module; The base mounting module is installed in the middle of the top of the chassis; mounting brackets are set at both ends of the top of the chassis, and a linear motion drive module is set on one of the mounting brackets. A rotary drive module is connected to the linear motion drive module. The linear motion drive module is used to drive the mask to move linearly along a preset direction, and the rotary drive module is used to drive the mask to rotate around the normal axis; a guide support module is set on the other mounting bracket; the rotary drive module and the guide support module are connected to the mask, and the mask is located above the base mounting module. The substrate mounting module includes a magnetic base, a rotating turntable, and a sample fixing stage, which are used to fix a flexible multilayer substrate. The magnetic base is connected to the chassis, the chassis is connected to the rotating turntable, and the sample fixing stage is set on the rotating turntable. The linear motion drive module, rotation drive module, rotating turntable, deposition module and control module are connected to set the motion trajectory, linear velocity, rotation angle, dwell time at each position and deposition time of the mask during the deposition process, so as to obtain a deposition thickness and stress field with spatial distribution differences on the surface of the flexible multilayer substrate.

[0008] As a further technical solution, multiple sets of the linear motion drive module, rotary drive module, and guide support module are provided, which are arranged along the height direction of the mounting frame, and different sets are connected to different masks.

[0009] As a further technical solution, the mask includes a detachable mask with multiple patterns. The mask is installed in a mask frame, and the pattern of the mask can be one or more of the following: a rectangular stripe mask, a round hole mask, and a square hole mask. As a further technical solution, the deposition module is disposed above the mask assembly and is used to provide directional deposition flux to the surface of the flexible multilayer substrate through the opening area of ​​the mask to form a rigid metal layer or other rigid layer material.

[0010] As a further technical solution, the deposition module can be a magnetron sputtering source, a thermal evaporation source, or an electron beam evaporation source for depositing metal thin films, alloy thin films, or inorganic rigid layers.

[0011] As a further technical solution, the linear motion drive module can be one of a lead screw slide, a guide rail slider, a stepper motor linear module, or a pneumatic slide rail; As a further technical solution, the mask is detachably installed in the mask frame by means of positioning holes, snaps, magnetic attraction or elastic pressure plates; As a further technical solution, there is a gap between the mask and the substrate, the gap being 0.1 to 5 mm.

[0012] Secondly, the present invention also provides a method for preparing a regionally differentiated layered wrinkled film using the above-described apparatus, comprising the following steps: A structural array with periodic first-order microstructures is prepared on the surface of a flexible substrate to obtain a flexible substrate layer; A liquid polymer layer is spin-coated onto the surface of the flexible substrate to form a flexible multilayer substrate, and the liquid polymer layer is kept in a liquid or semi-cured state. A sample fixing stage is fixed to a rotating turntable, so that the flexible multilayer substrate can rotate around its axis with the rotating turntable. Select a mask with a predetermined pattern from the mask library, install it in the mask frame, and connect it to the linear motion drive module and the rotary drive module; The control module simultaneously sets the motion trajectory of the mask and the rotation parameters of the flexible multilayer substrate, including the linear movement mode of the mask, the change of the mask's rotation angle, and the rotation speed and angle of the rotating disk. When the deposition module is in operation, selective deposition is carried out on the surface of the flexible multilayer substrate under the combined effect of dynamic masking and rotation of the flexible multilayer substrate, so that different areas form different deposition thicknesses or deposition rates. After deposition, the flexible multilayer substrate is cured or cooled. During the curing or cooling process, the regional stress gradient generated by the thickness difference of the rigid metal layer and the difference in thermal expansion coefficient between the layers of the flexible multilayer substrate is used to form a directional and hierarchical layered fold structure.

[0013] As a further technical solution, the mask can move in the following ways: unidirectional scanning, reciprocating scanning, stationary scanning, or a combination of translation and rotation.

[0014] As a further technical solution, by changing different mask patterns and repeating the deposition steps, multi-level ordered folded structures of different directions or scales can be constructed on the same substrate.

[0015] Thirdly, this invention proposes a layered wrinkled film based on regional difference regulation. The film surface is formed by the superposition of the primary microstructure of the flexible substrate and the secondary wrinkled structure caused by the thickness difference of the metal layer, which has a directional and layered wrinkled morphology and can be used for flexible electronic skin, strain or pressure sensing, optical regulation or information encryption display.

[0016] Compared with existing techniques for constructing folded structures through pre-stretching, thermal expansion, or solvent induction, this invention has the following significant advantages: 1. This invention simultaneously controls a linear motion drive module, a rotation drive module, and a rotating turntable of the substrate via a control module. During the deposition process, the motion trajectory, linear velocity, rotation angle, dwell time at each position, and rotation mode of the substrate are set, achieving coordinated movement between the mask and the flexible multilayer substrate. This results in a deposition thickness and stress field with spatially varying distribution on the surface of the flexible multilayer substrate. Using this device, spontaneous wrinkle formation can be induced solely through differences in metal deposition in localized areas, without requiring overall pre-stretching, overall heating, or solvent treatment, significantly simplifying the fabrication process. Furthermore, by changing different mask patterns and repeating the deposition steps, multi-level ordered wrinkle structures with different directions or scales can be constructed on the same substrate.

[0017] 2. The present invention has strong programmability of wrinkle morphology. Relying on a movable and rotatable mask assembly and a rotatable substrate mounting module, the mask pattern, mask movement trajectory, metal deposition thickness and deposition process parameters can all be freely set in the control module. By changing the mask scanning method (unidirectional, reciprocating, fixed-point dwell, translation and rotation combination) and the coordination relationship with the substrate rotation, a predetermined two-dimensional thickness field and stress field can be constructed on the surface of a flexible multilayer liquid-solid structure, so as to achieve precise control of wrinkle direction, period and layer, rather than just obtaining static patterned electrodes or thin films.

[0018] 3. This invention employs a combination structure of a rotating turntable and a sample fixing stage, enabling the flexible multilayer substrate to rotate around its central axis during the deposition process. Combined with a movable and rotatable mask, it is possible to achieve spatially controllable distribution of deposition thickness and stress field on substrates with primary microstructures (such as microcylindrical arrays and microlens arrays) or even curved surfaces. This allows for the creation of directional and hierarchical layered wrinkled structures on complex curved and microstructured surfaces, a feature not found in traditional planar substrate deposition devices and movable mask systems.

[0019] 4. This invention is based on a multilayer liquid-solid system deposition process consisting of a flexible substrate layer, a liquid or semi-solid polymer layer, and a rigid metal layer formed by subsequent deposition. The device has a simple structure and a high degree of modularity, and can be adapted to a variety of flexible substrate materials (such as polydimethylsiloxane, polyimide, polyurethane, etc.) and a variety of deposition methods (magnetron sputtering, thermal evaporation, electron beam evaporation, etc.). The motion and process parameters can be digitally set and repeatedly called through the control module, thus having the advantages of good process versatility, high repeatability of wrinkle morphology, and suitability for large-area and batch preparation. Attached Figure Description

[0020] Figure 1 Schematic diagram of a movable mask deposition apparatus Figure 1 ; Figure 2 Schematic diagram of a movable mask deposition apparatus Figure 2 ; Figure 3 A schematic diagram illustrating the fabrication of a curved, layered, wrinkled thin film based on regional variation control; Figure 4 A top view of a curved, layered, wrinkled thin film; Figure 5 A top view of a mask; Figures 6(a) and 6(b) show the morphology of a curved layered structure with a primary microstructure of a microcylindrical array. Figure 1 ; Figures 7(a) and 7(b) show the morphology of a curved layered structure with a microlens array as its primary microstructure. Figure 2 ; In the diagram: 1 is the chassis, 2 is the magnetic base, 3 is the rotating turntable, 4 is the sample fixing stage, 5 is the fastening bolt, 6 is the linear motion drive module; 7 and 8 are linear motion drive modules, 9 is the rotation drive module, 10 is the rectangular mask, 11 is the circular hole mask, 12 is the square hole mask, 13 is the guide support module, 14 is the guide support module, 15 is the guide support module, and 16 is the deposition module. 110 is a vacuum chamber, 120 is a deposition film formation method, 130 is a mask opening area, 140 is a mask, 150 is a curved layered fold, 160 is a primary microstructure, 170 is a planar region, 180 is a flexible substrate, and 190 is a liquid polymer. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the embodiments, but it is not limited thereto. Equivalent substitutions or modifications to specific structural forms, process parameters, etc., without departing from the spirit and scope of the technical solution of the present invention, should all be covered within the protection scope of the present invention.

[0022] To address the technical problems existing in the prior art, this invention discloses a movable mask device, deposition method, and obtained wrinkled structure for the fabrication of layered wrinkled structures. The device includes a chassis, a substrate mounting module, a mask motion assembly, a replaceable mask library, and a control module. The mask motion assembly consists of multiple linear motion drive modules and rotation drive modules, enabling programmable composite motion of the mask in translational and rotational directions. The mask library includes various patterns such as rectangular stripe masks, circular hole masks, and square hole masks, which are detachably installed in the mask frame. Spatial selective control of the deposition area is achieved by adjusting the motion trajectory and dwell time. The deposition module is located above the mask assembly and is used for directional deposition on the surface of a flexible multilayer substrate to form a rigid metal layer with varying thickness. The method of this invention, by selecting different mask patterns, setting the mask motion trajectory, and the deposition time, allows metal deposition on the surface of a flexible substrate to construct an adjustable regional thickness distribution. Subsequently, during the solidification of the liquid polymer or the cooling of the substrate, the spatial gradient between the rigid layer thickness and stress causes non-uniform strain at the interface, thereby spontaneously forming a layered wrinkled microstructure with directionality and hierarchy. This invention enables the programmable construction of folded structures without the need for traditional overall pre-stretching or external field loading. It has advantages such as simple structure, strong pattern adjustability, and good repeatability, and is suitable for fields such as flexible sensors, electronic skin, optical control, and information encryption.

[0023] Example 1 like Figure 1 As shown, this embodiment provides a deposition system for preparing layered wrinkled structures, including a chassis 1, a magnetic base 2 at the bottom of the chassis 1 for fixing the entire device, and a rotating turntable 3 in the middle of the chassis 1. A sample fixing stage 4 is installed on the rotating turntable 3 by fastening bolts 5 for supporting a flexible substrate 180 and the liquid polymer 190 coated thereon. Mounting brackets are installed at both ends of the top of chassis 1. A linear motion drive module is mounted on one of the mounting brackets, and a rotary drive module is connected to the linear motion drive module. The linear motion drive module drives the mask to move linearly along a preset direction, and the rotary drive module drives the mask to rotate around the normal axis. A guide support module is installed on the other mounting bracket. The rotary drive module and the guide support module are connected to the mask, and the mask is located above the substrate mounting module. The linear motion drive module and the rotary drive module are connected to a control module, which is used to set the motion trajectory, linear velocity, rotation angle, dwell time at each position, and deposition time of the mask during the deposition process, thereby obtaining a deposition thickness and stress field with spatial distribution differences on the surface of the flexible multilayer substrate. The control module simultaneously controls the linear motion drive module, the rotary drive module, and the rotating turntable of the substrate. During the deposition process, the motion trajectory, linear velocity, rotation angle, dwell time at each position, and rotation mode of the substrate are set to achieve coordinated movement of the mask and the flexible multilayer substrate, thereby obtaining a deposition thickness and stress field with spatial distribution differences on the surface of the flexible multilayer substrate. With the help of this device, spontaneous wrinkle formation can be induced by the difference in metal deposition film formation in local areas without the need for overall pre-stretching, overall heating or solvent treatment, which significantly simplifies the preparation process. At the same time, by changing different mask patterns and repeating the deposition steps, multi-level ordered wrinkle structures of different directions or scales can be constructed on the same substrate.

[0024] The aforementioned fold morphology is highly programmable. Relying on a movable and rotatable mask assembly and a rotatable substrate mounting module, the mask pattern, mask movement trajectory, metal deposition thickness, and deposition process parameters can all be freely set in the control module. By changing the mask scanning method (unidirectional, reciprocating, fixed-point dwell, translation and rotation combination) and its coordination with the substrate rotation, a predetermined two-dimensional thickness field and stress field can be constructed on the surface of a flexible multilayer liquid-solid structure, achieving precise control of the fold direction, period, and layer, rather than simply obtaining static patterned electrodes or thin films.

[0025] Specifically, in this embodiment, linear motion drive modules 6, 7, and 8 are provided on one of the mounting brackets to drive the rectangular mask 10, the circular hole mask 11, and the square hole mask 12 to move linearly along a preset direction. Specifically, linear motion drive module 6 drives the square hole mask 12, linear motion drive module 7 drives the circular hole mask 11, and linear motion drive module 8 drives the rectangular mask 10. Guide support modules 13, 14, and 15 are provided on the other mounting bracket. The other end of the rectangular mask 10, the circular hole mask 11, and the square hole mask 12 is supported and guided by the corresponding guide support modules 13, 14, and 15. In this embodiment, the rectangular mask 10, the circular hole mask 11, and the square hole mask 12 are arranged sequentially from top to bottom; the corresponding driving devices, the linear motion driving module 8, the linear motion driving module 7, and the linear motion driving module 6, are also arranged sequentially from top to bottom. Furthermore, a rotation drive module 9 is provided between the linear motion drive module 6, linear motion drive module 7, linear motion drive module 8 and the rectangular mask 10, the circular hole mask 11, and the square hole mask 12. The rotation drive module 9 is used to drive the mask to rotate around an axis perpendicular to the sample plane.

[0026] Select a rectangular mask 10, a circular hole mask 11, or a square hole mask 12 from the mask library, install them in the mask frame to form a mask 140, and connect it to the rotary drive module 9. Control the linear motion drive module 6, linear motion drive module 7, linear motion drive module 8, and rotary drive module 9 through a control system (not shown). This allows setting the motion trajectory, linear velocity, rotation angle, and dwell time of the mask 140 at each position during the deposition process, thereby achieving spatial and temporal selective control of the deposition area.

[0027] In use, the entire device is placed inside the vacuum chamber 110, with the flexible substrate 180 on the sample stage 4 facing the mask 140, and a certain gap maintained between the mask and the sample surface. The deposition module 120 (such as a magnetron sputtering target) is placed above the mask, and the deposition flux selectively reaches the flexible substrate 180 through the mask opening area 130 to achieve regional differential deposition.

[0028] Furthermore, during the deposition operation, a deposition module 16 is included. The deposition module 16 is disposed above the mask assembly and is used to provide directional deposition flux to the surface of the flexible multilayer substrate through the opening area of ​​the mask, forming a rigid metal layer or other rigid layer material. Specifically, the deposition module 16 can be a magnetron sputtering source, a thermal evaporation source, or an electron beam evaporation source, used to deposit metal thin films, alloy thin films, or inorganic rigid layers.

[0029] Furthermore, the rectangular mask 10, the round hole mask 11, and the square hole mask 12 are each detachably installed in the mask frame by means of positioning holes, snaps, magnetic attraction, or elastic pressure plates; Furthermore, there is a gap between the bottommost mask and the substrate, the gap ranging from 0.1 to 5 mm.

[0030] Specifically, the method for preparing a regionally differentiated layered wrinkled film using the above-mentioned apparatus includes the following steps: A structural array with periodic first-order microstructures is prepared on the surface of a flexible substrate to obtain a flexible substrate layer; A liquid polymer layer is spin-coated onto the surface of the flexible substrate to form a flexible multilayer substrate, and the liquid polymer layer is kept in a liquid or semi-cured state. A sample fixing stage is fixed to a rotating turntable, so that the flexible multilayer substrate can rotate around its axis with the rotating turntable. Select a mask with a predetermined pattern from the mask library, install it in the mask frame, and connect it to the linear motion drive module and the rotary drive module; The control module simultaneously sets the motion trajectory of the mask and the rotation parameters of the flexible multilayer substrate, including the linear movement mode of the mask, the change of the mask's rotation angle, and the rotation speed and angle of the rotating disk. When the deposition module is in operation, selective deposition is carried out on the surface of the flexible multilayer substrate under the combined effect of dynamic masking and rotation of the flexible multilayer substrate, so that different areas form different deposition thicknesses or deposition rates. After deposition, the flexible multilayer substrate is cured or cooled. During the curing or cooling process, the regional stress gradient generated by the thickness difference of the rigid metal layer and the difference in thermal expansion coefficient between the layers of the flexible multilayer substrate is used to form a directional and hierarchical layered fold structure. Furthermore, the flexible substrate material is polydimethylsiloxane, polyimide, or polyurethane film.

[0031] Furthermore, the metal deposition material is gold, silver, platinum, copper or an alloy thereof, and the deposition thickness difference is 10-200 nm.

[0032] Furthermore, the above method can be used to obtain a layered wrinkled film based on regional difference regulation. The film surface is formed by the superposition of the primary microstructure of the flexible substrate and the secondary wrinkled structure caused by the thickness difference of the metal layer. The superposition of the two forms a multi-scale layered wrinkled morphology, that is, a directional and hierarchical wrinkled morphology, which can be used for flexible electronic skin, strain or pressure sensing, optical control or information encryption display.

[0033] Furthermore, the movement mode of the mask sheet is unidirectional scanning, reciprocating scanning, stationary scanning, or a combination of translation and rotation scanning.

[0034] This embodiment employs a combination of a rotating turntable and a sample fixing stage, enabling the flexible multilayer substrate to rotate around its central axis during the deposition process. Combined with a movable and rotatable mask, it is possible to achieve spatially controllable distribution of deposition thickness and stress field on substrates with primary microstructures (such as microcylindrical arrays and microlens arrays) or even curved surfaces. This allows for the creation of directional and hierarchical layered wrinkled structures on complex curved and microstructured surfaces, a feature not found in traditional planar substrate deposition devices and movable mask systems.

[0035] This embodiment is based on a multilayer liquid-solid system deposition process consisting of a flexible substrate layer, a liquid or semi-solid polymer layer, and a rigid metal layer formed by subsequent deposition. The device has a simple structure and a high degree of modularity, and can be adapted to a variety of flexible substrate materials (such as polydimethylsiloxane, polyimide, polyurethane, etc.) and a variety of deposition methods (magnetron sputtering, thermal evaporation, electron beam evaporation, etc.). The motion and process parameters can be digitally set and repeatedly called through the control module, thus having the advantages of good process versatility, high repeatability of wrinkle morphology, and suitability for large-area and batch preparation.

[0036] The device proposed in this embodiment does not require overall external field drive: by achieving differences in metal deposition in local areas through mask design, spontaneous wrinkle formation can be induced, simplifying the preparation process; the morphology of this invention is highly programmable: the mask pattern, metal thickness and deposition parameters can be freely designed, achieving precise control of wrinkle direction, period and layer; this invention has high repeatability and consistency, the deposition process is stable and the parameters are controllable, and the resulting wrinkle structure is uniformly distributed and has good repeatability.

[0037] The material of this invention has broad compatibility and is applicable to a variety of flexible substrates and material systems, and has good process adaptability.

[0038] Example 2 like Figure 2 and Figure 3 As shown, this embodiment provides a movable mask device for fabricating layered folded structures disclosed in Embodiment 1. Figure 2 The method for performing wrinkling on the flexible substrate 180 shown specifically includes the following steps: First, a flexible substrate 180 is provided, and a microstructure array with periodic primary microstructures 160 is prepared on its surface. The primary microstructures can be microcylinder arrays, microlens arrays, or microgroove arrays, etc.

[0039] Subsequently, a liquid polymer 190 (such as PDMS prepolymer or polyurethane prepolymer) is spin-coated onto the surface of the flexible substrate 180 to form a liquid layer of uniform thickness. The liquid layer is then degassed under vacuum conditions to make the surface of the liquid layer smooth and free of obvious bubble defects.

[0040] A flexible substrate 180 coated with a liquid polymer layer 190 is mounted and fixed on a sample holder 4. A mask 140 with a set pattern (e.g., a rectangular mask 10) is selected from a mask library and mounted to a rotary drive module 9. The motion parameters of the linear motion drive module 6 and the rotary drive module 9, as well as the rotation parameters of the flexible multilayer substrate, are set by the control system, so that the mask 140 translates or rotates along a predetermined trajectory during the deposition process.

[0041] The deposition module 120 is activated, for example, by magnetron sputtering to deposit a metal thin film, so that the deposition particle beam passes through the mask opening area 130 and reaches the surface of the flexible substrate 180. Due to the dynamic shielding effect of the mask 140 during the deposition process, the deposition flux received by the flexible substrate 180 in different areas is different, thereby forming a rigid metal layer with spatial thickness differences on the surface of the flexible substrate.

[0042] The liquid polymer layer 190 is then cured, or the entire flexible multilayer structure is cooled. During the curing or cooling process, due to the difference in thickness of the metal layer and the difference in the coefficient of thermal expansion between the flexible substrate and the liquid polymer layer, a regional stress gradient is generated at the interface, inducing non-uniform buckling of the rigid layer and forming a directional and hierarchical curved layered wrinkled structure 150.

[0043] like Figure 4 As shown, a top view of the mask 140 is provided. The mask frame can be fixed to the rotary drive module 9 by threads, snaps, or magnetic attraction. The mask is detachably installed in the mask frame through positioning holes or edge limiting structures, thus forming a replaceable mask library. Depending on the directionality and periodicity requirements of the target wrinkled structure, masks with different patterns can be selected, and various deposition thickness distributions can be achieved by controlling the movement of the mask 140 in the translational and rotational directions.

[0044] Example 3 Based on Example 2, in this example, the primary microstructure 160 is a microcylindrical array, the flexible substrate 180 is a PDMS elastomer, and the liquid polymer layer 190 is a PDMS prepolymer. In the vacuum chamber 110, the deposition module 120 uses magnetron sputtering to deposit a gold film, with a sputtering current of, for example, 40 mA. The mask 140 is a rectangular mask 10. After curing and cooling, a large compressive stress is generated in the thicker areas of the metal layer, forming wrinkles with a larger period and higher amplitude; in the thinner areas of the metal layer, fine wrinkles are formed or the original microcylindrical morphology is basically preserved. As shown in Figures 6(a) and 6(b), the layered wrinkled structures after sputtering for 30 seconds and 60 seconds are respectively. The primary microcylindrical structure and the secondary wrinkled structure are superimposed, presenting a directional curved layered wrinkled morphology.

[0045] Example 4 Based on Example 2, the primary microstructure 160 was replaced with a microlens array, the flexible substrate 180 was a transparent elastomer material, the liquid polymer layer 190 was selected as PDMS prepolymer, and the deposition module 120 still used magnetron sputtering of gold film. The process parameters were the same as in Example 3. Similarly, by controlling the rotating disk 3 to rotate continuously at a preset speed during the deposition process, and coordinating with the translational or rotational movement of the mask 140, metal layers of different thicknesses were obtained on the substrate in different orientations. During the curing and cooling process, due to the combined effect of local curvature and the difference in metal layer thickness, different interface stresses were generated in different regions of the microlens array. As shown in Figures 7(a) and 7(b), the layered wrinkled structures were formed after sputtering for 30 seconds and 60 seconds, respectively. The layered wrinkled structures with certain regularity in both radial and circumferential directions were formed, indicating that the combination of substrate rotation and mask movement is beneficial to obtaining multi-dimensional adjustable wrinkled morphology.

[0046] Example 5 Based on Example 2, the rectangular mask 10 was selected and adopted the following three motion modes: (1) linear scanning only: the mask 140 moves back and forth at a constant speed in a single direction; (2) fixed-point dwell: the mask dwells at several predetermined positions for a long time and then moves rapidly in the middle; (3) translation and rotation combination: the mask rotates at a certain angular velocity while translating and scanning. In the above three cases, the rotation speed and rotation direction of the rotating disk 3 can be controlled to make the flexible multilayer substrate rotate synchronously or in segments during the deposition process. The experimental results show that under the simple linear scanning condition, the fold structure is mainly arranged along the scanning direction; under the fixed-point dwell condition, the thickness of the local area increases significantly and the fold amplitude is significantly improved; under the translation and rotation combination condition and the substrate rotates synchronously, the fold structure exhibits a more complex spatial morphology such as intersection and torsion, indicating that the device of the present invention can achieve multi-dimensional programmable control of the fold directionality and hierarchy by controlling the mask motion mode and combining it with the substrate rotation.

[0047] Example 6 Based on Example 2, a rectangular mask 10 is first used for deposition, forming a thickness difference region arranged along a certain direction on the surface of the flexible substrate 180. During this process, the rotating disk 3 drives the substrate to rotate at a first preset speed. Then, a circular aperture mask 11 is used for a second deposition. During the second deposition, different substrate rotation parameters (e.g., different speeds or segmented rotation modes) can be selected to further increase the thickness of the metal layer in local areas and make the thickness distribution direction different. After curing or cooling, due to the superposition of thickness and stress formed by the two depositions, a more detailed local fold structure is generated in the second deposition area on the basis of the directional folds formed in the first deposition. Finally, a multi-level layered fold structure with superposition of primary and secondary fold directions is obtained. The thickness and stress difference introduced by different rotation conditions can be reflected in both the circumferential and radial directions, realizing a more complex stress field design and morphology control in space.

[0048] Example 7 This embodiment discloses a specific application of the curved layered wrinkled film. Specifically, the curved layered wrinkled film prepared in Example 3 can be used as the strain-sensitive layer, bonded to a flexible substrate or elastic support structure, and silver paste can be applied to both ends of the film and connected with wires as electrodes to prepare a flexible strain sensor sample. Under uniaxial tensile conditions, when strain is applied along the main direction of the wrinkles, the wrinkles gradually unfold along the strain direction, the conductive path changes, and the resistance increases significantly with strain. When strain is applied perpendicular to the main direction of the wrinkles, the resistance change is small, and the sensor exhibits obvious directional selectivity. This result shows that the layered wrinkled film prepared by the movable mask deposition device of this invention not only has programmable morphology but also possesses excellent flexibility and directional sensitivity, making it suitable for fields such as flexible electronic skin, multi-directional strain or pressure sensing, and tunable optical devices.

Claims

1. A deposition system for the preparation of hierarchical wrinkle structures, characterized in that, The system comprises a base plate, a substrate mounting module, a mask movement assembly, a mask, a deposition module and a control module. The substrate mounting module is mounted on the middle of the top of the base plate; two mounting racks are arranged on the two ends of the top of the base plate; a linear movement driving module is arranged on one of the mounting racks; a rotary driving module is connected to the linear movement driving module; the linear movement driving module is used to drive the mask to move linearly in a preset direction; the rotary driving module is used to drive the mask to rotate around a normal axis; a guide support module is arranged on the other mounting rack; the rotary driving module and the guide support module are connected to the mask, and the mask is arranged above the substrate mounting module. The substrate mounting module comprises a magnetic base, a rotary disc and a sample fixing table, which are used to fix a flexible multilayer substrate; the magnetic base is connected to the base plate; the base plate is connected to the rotary disc; the sample fixing table is arranged on the rotary disc. The linear movement driving module, the rotary driving module, the rotary disc, the deposition module and the control module are connected, which are used to set the movement trajectory, linear velocity, rotation angle, residence time at each position and deposition time of the mask in the deposition process, so that the deposition thickness and stress field with spatial distribution difference are obtained on the surface of the flexible multilayer substrate.

2. The deposition system for layered fold structure fabrication of claim 1, wherein, The linear movement driving module, the rotary driving module and the guide support module are arranged in multiple groups, which are arranged along the height direction of the mounting rack, and different groups are connected to different masks.

3. The deposition system for layered pleats structure fabrication of claim 1, wherein, The mask comprises a plurality of detachable masks with different patterns; the mask is mounted in a mask frame; the pattern of the mask can be one or more of a rectangular stripe mask, a circular hole mask and a square hole mask.

4. The deposition system for layered pleats fabrication of claim 1, wherein, The deposition module is arranged above the mask assembly, which is used to provide directional deposition flux to the surface of the flexible multilayer substrate through the opening area of the mask, so as to form a metal rigid layer or other rigid layer material.

5. The deposition system for layered pleated structure fabrication of claim 1, wherein, The mask is detachably mounted in the mask frame by means of positioning holes, buckles, magnetic attraction or elastic pressing plates.

6. A method of making a regionally-differently modulated layered folded film using the apparatus of any one of claims 1 to 5, characterized in that, The method comprises the following steps: A structure array with a periodic primary microstructure is prepared on the surface of a flexible substrate to obtain a flexible substrate layer; A liquid polymer layer is spin-coated on the surface of the flexible substrate layer, so that the flexible multilayer substrate is formed, and the liquid polymer layer is in a liquid state or a semi-cured state; The flexible multilayer substrate is fixed on the sample fixing table of the rotary disc, so that the flexible multilayer substrate can rotate around the axis of the rotary disc; A mask with a predetermined pattern is selected from a mask library, mounted in a mask frame and connected to the linear movement driving module and the rotary driving module; The movement trajectory of the mask and the rotation parameters of the flexible multilayer substrate are set by the control module, including the linear movement mode of the mask, the rotation angle change of the mask, the rotation speed and the rotation angle of the rotary disc; Under the working state of the deposition module, the surface of the flexible multilayer substrate is selectively deposited under the combined action of the dynamic shielding of the mask and the rotation of the flexible multilayer substrate, so that different regions form different deposition thicknesses or deposition rates. After the deposition, the flexible multilayer substrate is solidified or cooled, and during the solidification or cooling, the regional stress gradient caused by the difference in thickness of the metal rigid layer and the difference in thermal expansion coefficient between the layers of the flexible multilayer substrate forms a hierarchical and directional layered wrinkle structure.

7. The method of claim 6, wherein, The movement mode of the mask is one-way scanning, reciprocating scanning, fixed-point staying scanning, or a combination of translation and rotation.

8. The method of claim 6, wherein, By replacing different mask patterns and repeating the deposition step, a multi-level ordered wrinkle structure of different directions or different scales can be constructed on the same substrate.

9. The method of claim 6, wherein, The flexible substrate material is a polydimethylsiloxane, polyimide or polyurethane film; the metal deposition material is gold, silver, platinum, copper or an alloy thereof, and the difference in deposition thickness is 10-200 nm.

10. A hierarchical pleated film based on zonal differential regulation, characterized in that, The method of any one of claims 7-9 is obtained, wherein the surface of the thin film is formed by superimposing the primary microstructure of the flexible substrate and the secondary wrinkle structure caused by the difference in thickness of the metal layer, and has a hierarchical and directional wrinkle morphology.

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