Display panel, display device, three-dimensional microstructure device and preparation method thereof

Abstract

The application discloses a display panel, a display device, a three-dimensional microstructure device and a preparation method of the three-dimensional microstructure device. The preparation method comprises the following steps: preparing a functional layer, a thin film actuator and a device layer, wherein the thin film actuator is located between the functional layer and the device layer; performing a set process to make the thin film actuator expand, so that the functional layer is away from the device layer; and processing the device layer or the functional layer in the state that the functional layer is away from the device layer, so as to prepare the three-dimensional microstructure device. The above method can improve the process precision of the three-dimensional microstructure, and guarantees the product performance and yield of the three-dimensional microstructure device.

Description

Technical Field

[0001] This application relates to the field of microelectromechanical systems (MEMS) technology, and in particular to a display panel, display device, three-dimensional microstructure device, and method for fabricating the same. Background Technology

[0002] MEMS, or Micro Electro Mechanical System, focuses on ultra-precision machining and refers to independent devices with dimensions on the micrometer or even nanometer scale. MEMS is a high-tech electromechanical device developed based on semiconductor manufacturing technology, integrating techniques such as photolithography, etching, thin film processing, LIGA (Lithographie, Galvanoformung, Abformung, i.e., photolithography, electroforming, and injection molding), silicon micromachining, non-silicon micromachining, and precision machining.

[0003] Three-dimensional micromechanical structures are typically characterized by their small size, light weight, and high functional integration, and they have wide applications in fields such as microsensing, fiber optic communication, micromechanical structures, micro-power supplies, micro-energy, micro-analysis, and micro-actuators. These complex three-dimensional microstructures can be realized through multiple photoresist coating and re-exposure methods, gray-tone mask lithography, or bonding processes. However, the multiple photoresist coating and re-exposure process involves alignment of upper and lower layers and must also consider factors such as photoresist miscibility; the gray-tone mask process has high manufacturing costs and technical difficulty, and usually requires thick photoresist coatings, making the process complex; while bonding processes cannot handle multilayer thin-film three-dimensional micromechanical structures. In general, all three of these processes are limited by the limited uniformity of film formation, the distribution of light source intensity in the exposure machine, and the inability to locally adjust the exposure focal length, thus affecting the process accuracy of three-dimensional micromechanical structures.

[0004] Therefore, improving the fabrication accuracy of three-dimensional micromechanical structures has become an urgent problem to be solved in the field of MEMS. Summary of the Invention

[0005] In view of the above problems, the present invention provides a display panel, a display device, a three-dimensional microstructure device and a method for fabricating the same, so as to improve the process accuracy and product yield of three-dimensional micromechanical structures.

[0006] Firstly, a method for fabricating a three-dimensional microstructure device is provided, comprising:

[0007] A functional layer, a thin-film actuator, and a device layer are fabricated, wherein the thin-film actuator is located between the functional layer and the device layer;

[0008] The thin-film actuator is expanded by performing a set process to move the functional layer away from the device layer;

[0009] With the functional layer located away from the device layer, the device layer or the functional layer is processed to fabricate the three-dimensional microstructure device.

[0010] Optionally, the material of the thin-film actuator is one of thermally responsive shape memory material, photosensitive shape memory material, pH-induced shape memory material, electrosensitive shape memory material, and magnetosensitive shape memory material;

[0011] The setting process is a corresponding process associated with the material of the thin film actuator; the corresponding process includes heating process, light irradiation process, pH adjustment process, electric field application process, and magnetic field application process.

[0012] Optionally, the thermally responsive shape memory material is one of polyethylene-vinyl acetate, polyurethane, polycaprolactone, and their copolymers.

[0013] Optionally, the execution setting process expands the thin-film actuator to move the functional layer away from the device layer, including:

[0014] The process of setting up the thin film actuator expands, pushing the contact area of ​​the device layer away from the functional layer, and making the contact area and the surrounding area tend to be on the same plane;

[0015] The contact area is the area where the device layer contacts the thin-film actuator, and the peripheral area is the area where the device layer is connected to the contact area.

[0016] Optionally, the fabrication of the functional layer, thin-film actuator, and device layer includes:

[0017] The functional layer is prepared, and the recessed areas in the functional layer are detected;

[0018] The thin-film actuator is formed within the recessed area;

[0019] The device layer is formed on the functional layer on which the thin-film actuator is formed.

[0020] Optionally, the three-dimensional microstructure device is the bottom electrode in the display panel;

[0021] The step of preparing the functional layer and detecting the recessed areas in the functional layer includes: providing a first substrate, forming a dielectric layer on the first substrate, and detecting the recessed areas in the dielectric layer; wherein the first substrate and the dielectric layer constitute the functional layer.

[0022] The step of forming the device layer on the functional layer on which the thin-film actuator is formed includes:

[0023] An electrode material layer is formed on the functional layer on which the thin-film actuator is formed as the device layer, and a photoresist layer is formed on the electrode material layer;

[0024] The execution setting process causes the thin-film actuator to expand, pushing the contact area of ​​the device layer away from the functional layer, and bringing the contact area and the surrounding area to the same plane, including:

[0025] The first substrate is pre-baked to cause the thin film actuator to expand and deform due to heat, pushing the electrode material layer on the thin film actuator away from the functional layer, and making the electrode material layer on the thin film actuator and the electrode material layer in the peripheral area tend to be on the same plane.

[0026] The process of fabricating the device layer or the functional layer to prepare the three-dimensional microstructure device, wherein the functional layer is located away from the device layer, includes:

[0027] The photoresist layer is exposed, developed, and post-baked, and the electrode material layer is etched to obtain the bottom electrode.

[0028] Optionally, the fabrication of the functional layer, thin-film actuator, and device layer includes:

[0029] The functional layer is prepared, and the step region in the functional layer is determined;

[0030] The thin-film actuator is formed on the lower side of the stepped region;

[0031] The device layer is formed on the stepped region where the thin-film actuator is formed.

[0032] Optionally, the three-dimensional microstructure device is a cantilever beam in the display panel;

[0033] The preparation of the functional layer and the determination of the step region in the functional layer include:

[0034] A second substrate is provided, and an organic film layer is formed in a defined area of ​​the second substrate, wherein the second substrate and the organic film layer constitute the functional layer; wherein the area at the junction of the organic film layer and the second substrate is the step region;

[0035] The step region on which the thin-film actuator is formed includes forming the device layer, comprising:

[0036] A cantilever beam material layer is formed on the step region where the thin film actuator is formed as the device layer, and a photoresist layer is formed on the cantilever beam material layer;

[0037] The execution setting process causes the thin-film actuator to expand, the contact area of ​​the device layer to move away from the functional layer, and the contact area to tend to be on the same plane as the surrounding area, including:

[0038] The second substrate is pre-baked to cause the thin film actuator to expand and deform due to heat, pushing the cantilever beam material layer on the thin film actuator away from the functional layer, and making the cantilever beam material layer on the thin film actuator and the cantilever beam material layer on the higher side of the step region tend to be on the same plane.

[0039] The process of fabricating the device layer or the functional layer to prepare the three-dimensional microstructure device, wherein the functional layer is located away from the device layer, includes:

[0040] The photoresist layer is exposed, developed, and post-baked, and the cantilever beam material layer is etched to obtain the cantilever beam.

[0041] Optionally, the execution setting process expands the thin-film actuator to move the functional layer away from the device layer, including:

[0042] The thin-film actuator is expanded by performing a set process to isolate the functional layer from the device layer.

[0043] Optionally, the three-dimensional microstructure device is a suspended membrane bridge in the display panel;

[0044] The fabrication of the functional layer, thin-film actuator, and device layer includes:

[0045] A third substrate is provided, wherein an anchor mechanism and a sacrificial layer are formed in region AA of the third substrate, the third substrate and the sacrificial layer being the functional layer; a thin-film actuator is formed on the sacrificial layer; and a film bridge layer is formed on the thin-film actuator and the anchor mechanism as the device layer.

[0046] The process of performing a setting procedure causes the thin-film actuator to expand in order to isolate the functional layer from the device layer, including:

[0047] The third substrate is heated to cause the thin film actuator to expand and deform, thereby isolating the sacrificial layer from the membrane bridge layer.

[0048] The process of fabricating the device layer or the functional layer to prepare the three-dimensional microstructure device, wherein the functional layer is located away from the device layer, includes:

[0049] Release the sacrificial layer so that the membrane bridge layer and the anchoring mechanism form the suspended membrane bridge.

[0050] Based on the same inventive concept, in a second aspect, a three-dimensional microstructure device is provided, comprising: a substrate, a thin-film actuator, and a three-dimensional microstructure; the thin-film actuator is located between the substrate and the three-dimensional microstructure, or inside the three-dimensional microstructure; the thin-film actuator expands during the formation of the three-dimensional microstructure device.

[0051] Based on the same inventive concept, a third aspect provides a display panel that includes the three-dimensional microstructure device provided in the second aspect.

[0052] Based on the same inventive concept, a fourth aspect provides a display device including the display panel provided in the third aspect.

[0053] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0054] This invention provides a method for fabricating three-dimensional microstructure devices. By forming a thin-film actuator between a functional layer and a device layer, and then by setting a process to cause the thin-film actuator to expand and deform, the functional layer is moved away from the device layer. In this way, when the functional layer or device layer is subsequently processed to fabricate the three-dimensional microstructure device, the expanded thin-film actuator can repair the uniformity of the film formation of the functional layer, compensate for the exposure intensity distribution and exposure focal plane, and improve the isolation effect between the device layer and the functional layer. This improves the process accuracy of the three-dimensional micromechanical structure and ensures the product performance and yield of the three-dimensional microstructure device.

[0055] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0056] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0057] In the attached diagram:

[0058] Figure 1 A schematic diagram of the fabrication method of the three-dimensional microstructure device provided in the embodiment of the present invention is shown;

[0059] Figure 2A A schematic diagram of a recessed region on a dielectric layer in the prior art is shown;

[0060] Figure 2B It shows Figure 2A Schematic diagram of BB' cross section in the middle;

[0061] Figure 2C A schematic diagram of the preparation method of Embodiment 1 of the present invention is shown;

[0062] Figure 2D A schematic diagram of a thin-film actuator formed between a recessed region of a dielectric layer and an electrode material layer according to Embodiment 1 of the present invention is shown;

[0063] Figure 2E A schematic diagram of the thin-film actuator after expansion deformation according to Embodiment 1 of the present invention is shown;

[0064] Figure 3A A schematic diagram of a cantilever beam structure in the prior art is shown;

[0065] Figure 3B It shows Figure 3A Schematic diagram of BB' cross section in the middle;

[0066] Figure 3C A schematic diagram of the preparation method of Embodiment 2 of the present invention is shown;

[0067] Figure 3D A schematic diagram of a thin-film actuator formed on the lower side of the step region is shown in Embodiment 2 of the present invention;

[0068] Figure 3E A schematic diagram of the thin-film actuator after expansion deformation according to Embodiment 2 of the present invention is shown;

[0069] Figure 4A A schematic diagram of a suspended membrane bridge in the prior art is shown;

[0070] Figure 4B It shows Figure 4A Schematic diagram of BB' cross section in the middle;

[0071] Figure 4C A schematic diagram of the preparation method of Embodiment 3 of the present invention is shown;

[0072] Figure 4D A schematic diagram of a thin-film actuator formed between the sacrificial layer and the membrane bridge layer in Embodiment 3 of the present invention is shown;

[0073] Figure 4E A schematic diagram of the thin-film actuator after expansion deformation according to Embodiment 3 of the present invention is shown;

[0074] Explanation of reference numerals in the attached figures:

[0075] 1. Functional layer; 11. First substrate; 12. Dielectric layer; 13. Second substrate; 14. Organic film layer; 15. Third substrate; 16. Sacrificial layer; 17. Anchor mechanism; 2. Thin film actuator; 3. Device layer; 31. Electrode material layer; 32. Cantilever beam material layer; 33. Film bridge layer; 4. Photoresist layer. Detailed Implementation

[0076] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0077] Currently, the fabrication of micromechanical structures mainly utilizes semiconductor thin-film processing techniques, including patterning using photolithography and etching on the basis of thin-film deposition. Some movable micromechanical structures also involve the use of etching techniques to release corresponding structural units from the front or back. Due to the inherent uniformity and stability of thin-film deposition processes such as magnetron sputtering, chemical vapor deposition, sol-gel methods, and pulsed laser deposition, the uniformity of the film is limited. After each photolithography coating, the photoresist spreads out according to the shape, and there will be nanoscale or even micrometer-level subtle differences on its surface. At the same time, due to the inability to locally adjust the intensity distribution of the light source and the exposure focal length of the exposure machine, it is difficult to form micrometer-level fine structures, especially patterns with complex three-dimensional structures, in a single exposure. High aspect ratio processing or bulk processing is required, which significantly increases the process cost.

[0078] Therefore, in order to solve the above problems and improve the manufacturing accuracy of three-dimensional microstructures, such as Figure 1 As shown, this invention provides a method for fabricating a three-dimensional microstructure device, the overall concept of which includes steps S1 to S3, as detailed below:

[0079] S1: Fabricate a functional layer, a thin-film actuator, and a device layer, wherein the thin-film actuator is located between the functional layer and the device layer.

[0080] Specifically, the functional layer in this embodiment can be interpreted as the substrate part in a three-dimensional microstructure device. The functional layer can be a substrate, such as a silicon substrate; it can be a substrate, such as a transparent glass substrate; it can also include an insulating layer, a dielectric layer, an organic material layer or a sacrificial layer formed on the substrate or substrate, etc., without specific limitations.

[0081] Device layers can be interpreted as key material layers that form three-dimensional microstructures. For example, source / drain metal layers can be device layers in thin-film transistors, electrode material layers can be device layers for the bottom electrode in a display panel, cantilever beam material layers can be device layers for the cantilever beam in a display panel, and so on.

[0082] Thin-film actuators belong to the category of micro-actuators. They are microstructures capable of converting other forms of energy, such as light, heat, and electromagnetic energy, into mechanical energy. When subjected to related processing techniques, such as illumination, heating, or the application of electric or magnetic fields, they can output mechanical energy through expansion and deformation. Therefore, thin-film actuators are mechanisms formed from thin-film materials with shape memory effects. Different types of shape memory materials, such as thermally responsive shape memory materials, photosensitive shape memory materials, pH-induced shape memory materials, electrosensitive shape memory materials, and magnetosensitive shape memory materials, can all be used to form the thin-film actuator required in this embodiment.

[0083] Thin-film actuators can be single-layer or double-layer organic thin films or other thin films with shape memory effects. For example, for thermoresponsive shape memory materials, semi-crystalline polymers with reversible shape memory effects are preferred, including: polyethylene-vinyl acetate, polyurethane, polycaprolactone, and their copolymers. Specifically, these include polymer materials such as polyacrylic acid-b-polyN-isopropylacrylamide, polymethacrylic acid-b-polyN-isopropylacrylamide, and polymethacrylic alcohol-b-polyN-isopropylacrylamide. Thermoresponsive thin-film actuators can be prepared using semiconductor film deposition processes, such as spin coating or atomic layer deposition.

[0084] Photoinduced shape memory materials can be further divided into photochemical reaction type and photothermal effect type. Selectable materials include: acrylic ester copolymers grafted with cinnamic acid groups, acrylate copolymers or polyurethanes, carbon nanotube-filled thermoplastic elastomers, and gold nanorods incorporating tert-butyl acrylate or polyamino acid esters, etc.

[0085] For pH-induced shape memory materials, available materials include: cellulose nanofiber polyurethane, polyacrylamide with added dansylamide groups, phosphorylated cellulose nanofiber composite polyurethane, etc.

[0086] For electro-induced shape memory materials, the available materials include: carbon black-filled shape memory thermosetting polystyrene composites, carbon nanotube-filled shape memory polyurethane composites, carbon nanotube-filled shape memory thermosetting polyurethane composites, etc.

[0087] For magnetostrictive shape memory materials, selectable materials include polylactic acid, polycaprolactone, and polyurethane with added magnetic particles such as γ-Fe2O3, Fe3O4, and NdFeB.

[0088] S2: Perform a set process to expand the thin-film actuator so that the functional layer is moved away from the device layer.

[0089] Thin-film actuators with shape memory effect undergo expansion deformation when subjected to a setting process corresponding to their shape memory type, which causes the functional layer to move away from the device layer.

[0090] For example, for thermally responsive thin-film actuators, the corresponding process is heating. In the fabrication of display panels, the pre-baking and post-baking stages in photolithography can serve as the corresponding process, causing the thin-film actuator to undergo minute expansion deformation under the thermal stimulation of pre-baking and post-baking. For light-responsive thin-film actuators, the corresponding process is turning on illumination, causing the thin-film actuator to undergo minute expansion deformation under specific light intensities. For pH-responsive thin-film actuators, the corresponding process is adjusting the ambient pH value, causing the thin-film actuator to undergo minute expansion deformation within a specific pH range. For electrically responsive thin-film actuators, the corresponding process is applying an electric field, causing the thin-film actuator to undergo minute expansion deformation under specific electric field strengths. For magnetically responsive thin-film actuators, the corresponding process is applying a magnetic field, causing the thin-film actuator to undergo minute expansion deformation under specific magnetic field strengths.

[0091] It should be noted that the functional layer being far from the device layer can be achieved in two ways: either the thin-film actuator pushes the functional layer away from the device layer, i.e., the moving body is the functional layer; or the thin-film actuator pushes the device layer away from the functional layer, i.e., the moving body is the device layer. On the other hand, it can be that a part of the functional layer is far from the device layer, or the entire functional layer is far from the device layer; there is no specific limitation on this.

[0092] Types of functional layers that are far from device layers include, but are not limited to:

[0093] Type 1: Alignment of device layers with varying heights in different areas. Alignment of device layers is achieved by expanding the actuator film. This overcomes the problem of uneven light source intensity distribution in exposure machines, or repairs defects caused by uneven MEMS film deposition, thereby improving exposure uniformity and ensuring the performance or yield of 3D microstructured devices. It also overcomes the problem of the exposure focal length being unable to be locally adjusted in exposure machines, reducing the number of exposure cycles during the fabrication of 3D microstructured devices and compensating for the exposure focal length, thus improving exposure quality.

[0094] Type 2: Spatial isolation between the device layer and the functional layer. Specifically, a predetermined process is performed to expand the thin-film actuator, thereby isolating the functional layer from the device layer. The expansion of the actuator thin film improves the isolation quality between the device layer and the functional layer, preventing adhesion between the device layer and the isolation layer, which could affect the performance of the three-dimensional microstructure device.

[0095] For type 1, it includes, but is not limited to, two cases: exposure uniformity compensation and exposure focal plane compensation.

[0096] For scenario 1: exposure uniformity compensation, step S1 is specifically as follows:

[0097] A functional layer is prepared, and the recessed areas in the functional layer are detected; a thin-film actuator is formed in the recessed areas; and a device layer is formed on the functional layer on which the thin-film actuator is formed.

[0098] Specifically, due to limitations in the uniformity of the film deposition process and the intensity distribution of the light source in the exposure machine, some delicate micromechanical structures will exhibit localized unevenness after photoresist coating. This can lead to underexposure in some areas and overexposure in others. To address this issue, a thin-film actuator is formed within the recessed area of ​​the functional layer.

[0099] For scenario 2: exposure focal plane compensation, step S1 is as follows:

[0100] A functional layer is prepared, and a step region in the functional layer is defined; a thin-film actuator is formed on the lower side of the step region; a device layer is formed on the step region where the thin-film actuator is formed.

[0101] Specifically, since current exposure processes are all planar, and some complex three-dimensional micromechanical structures often require simultaneous exposure on film layers at different heights, and the exposure focal length of the exposure machine cannot be locally adjusted, some patterns will become out of focus and blurry, resulting in the AutoFocus Error problem. To solve this problem, a thin-film actuator is fabricated on the lower side of the step region, and the height of the focusing surface is compensated by the expansion and deformation of the thin-film actuator.

[0102] Step S2 for the two scenarios described above corresponds to the following:

[0103] The process of setting up the thin film actuator causes it to expand, pushing the contact area of ​​the device layer away from the functional layer and bringing the contact area and the surrounding area to the same plane; where the contact area is the area where the device layer contacts the thin film actuator, and the surrounding area is the area where the device layer is connected to the contact area.

[0104] "Tending to the same plane" means that the contact area of ​​the device layer is aligned with the surrounding area as much as possible, or the height difference between the two is less than a set threshold.

[0105] S3: With the functional layer far away from the device layer, process the device layer or the functional layer to prepare the three-dimensional microstructure device.

[0106] Keeping the functional layer and the device layer far apart can be achieved by continuously executing the set process, or by quickly executing subsequent processes after the set process is completed, so as to complete the fabrication of the three-dimensional microstructure device before the expansion and deformation of the thin film actuator recovers.

[0107] This embodiment provides a method for fabricating a three-dimensional microstructure device. By forming a thin-film actuator between the functional layer and the device layer, and then by setting a process to cause the thin-film actuator to expand and deform, the functional layer is moved away from the device layer. In this way, when the functional layer or device layer is subsequently processed to fabricate the three-dimensional microstructure device, the expanded thin-film actuator can play a role in repairing the uniformity of the film formation of the functional layer, compensating for the exposure intensity distribution and exposure focal plane, or improving the isolation effect between the device layer and the functional layer. This improves the process accuracy of the three-dimensional micromechanical structure and ensures the product performance and yield of the microelectromechanical system.

[0108] To more fully illustrate the above solution, the following description will focus on specific application scenarios of the present invention in the field of display panels:

[0109] Example 1: Fabrication of the bottom electrode in a display panel.

[0110] Before fabricating the bottom electrode, the array substrate in a display panel first deposits a dielectric layer 12: SiO, approximately several hundred nanometers thick, and then deposits the electrode material layer 31: Ti / Al / Ti. In current technology, due to limitations in the film deposition process, multiple defects occur on the surface of the dielectric layer 12, manifesting as recessed areas, such as… Figure 2A elliptical regions and Figure 2B The cross-section of the elliptical region is shown in the image. If left unrepaired, the photoresist will flow along the shape after coating and solidify, resulting in defects. These defects may even be amplified during electrode metal deposition, adversely affecting subsequent processes.

[0111] To solve this problem, the specific solution adopted in this embodiment is as follows: Figure 2C As shown, it includes the following steps:

[0112] S111: Provide a first substrate 11, and form a dielectric layer 12 on the first substrate 11; detect the recessed area of ​​the dielectric layer 12; the first substrate 11 and the dielectric layer 12 are functional layers 1;

[0113] Specifically, the first substrate 11 can be a glass substrate. Then, an 800nm ​​layer of SiO is deposited on the first substrate 11 using plasma-enhanced chemical vapor deposition (PEVCD). Finally, surface defects are detected using a film thickness gauge, microscope, and other measuring tools to determine... Figure 2A The recessed area shown.

[0114] S112: A thin film actuator 2 is formed in the recessed area;

[0115] like Figure 2DAs shown, a patterned thin-film actuator 2 is formed within the recessed area. The thin film can be formed using spin-coating or atomic layer deposition (ALD). In this embodiment, the thin-film actuator 2 is thermally responsive and is made of polyacrylic acid-b-polyN-isopropylacrylamide. The film thickness can be adjusted according to the defect conditions, such as from 2 nm to 900 nm.

[0116] S113: An electrode material layer 31 is formed on the functional layer 1 on which the thin film actuator 2 is formed as a device layer 3, and a photoresist layer 4 is formed on the electrode material layer 31.

[0117] Specifically, the electrode material layer 31 can be deposited by sputter magnetron sputtering or vapor deposition, with the deposited material being Ti / Al / Ti, and an example thickness of 50nm / 700nm / 50nm. Then, photoresist is coated onto the electrode material layer 31 to form a photoresist layer 4. This can be achieved using a slot die or spin-coating method, with an example thickness of 1.5μm.

[0118] S21: Pre-bake the first substrate 11 to cause the thin film actuator 2 to expand and deform due to heat, pushing the electrode material layer 31 on the thin film actuator 2 away from the functional layer 1, and making the electrode material layer 31 on the thin film actuator 2 and the electrode material layer 31 in the surrounding area tend to be on the same plane.

[0119] Specifically, the pre-baking temperature is the current pre-baking temperature of 110℃ for display panels, lasting for 150 seconds. The thin-film actuator 2 undergoes rapid expansion and deformation upon heating, with a deformation amount ranging from a few nanometers to several hundred nanometers, causing the electrode material layer 31 and photoresist layer 4 in the recessed area to tend towards the same plane as the surrounding normal area, such as... Figure 2E As shown. Due to the slow thermal recovery rate of polyacrylic acid-b-polyN-isopropylacrylamide, the film did not fully recover its original state after the substrate cooled down.

[0120] S31: Expose, develop, and bake the photoresist layer 4, and etch the electrode material layer 31 to obtain the bottom electrode.

[0121] First, exposure is performed. At this time, the thin film actuator 2 remains in an expanded state to provide certain compensation for the focal plane of the recessed area, so that the recessed area of ​​the electrode material layer 31 is on the same focal plane as the surrounding normal area, thus ensuring the exposure effect.

[0122] Next, development is performed to wash away the exposed photoresist; then, a post-bake is performed at 120°C for 120 seconds. Since the photoresist is not completely cured after development and still has some fluidity, the post-bake process allows the thin-film actuator 2 to remain in a state of thermal expansion, ensuring that the pattern is consistent with the exposure process.

[0123] Next, etching is performed to obtain a patterned metal electrode, i.e., the bottom electrode.

[0124] In this embodiment, the thermally responsive thin-film actuator 2 expands and deforms when heated, compensating for the local exposure uniformity of the coated substrate. This keeps the device layer 3 and photoresist layer 4 at different positions on the same plane during the exposure process, eliminating the adverse effects of the recessed area and improving the exposure effect. This embodiment is suitable for thin-film actuators 2 with small deformation (<10μm).

[0125] Example 2: Fabrication of a cantilever beam in a display panel.

[0126] When fabricating a cantilever beam on the array substrate of a display panel, it is necessary to first fabricate an organic film layer 14 on the substrate, and then create the cantilever beam at the intersection of the organic film layer 14 and the substrate, such as... Figure 3A As shown. Currently, because the thickness of organic films is approximately tens of micrometers, such as Figure 3B As shown, it exceeds the exposure focal length range of the exposure machine, which easily leads to blurry patterns and makes it impossible to obtain a complete cantilever beam pattern.

[0127] To solve this problem, the solution adopted in this embodiment is as follows: Figure 3C As shown, it includes the following steps:

[0128] S121: A second substrate 13 is provided, and an organic film layer 14 is prepared in a defined area of ​​the second substrate 13. The second substrate 13 and the organic film layer 14 are functional layers 1; wherein, the area at the junction of the organic film layer 14 and the second substrate 13 is a step area.

[0129] The second substrate 13 can be a glass substrate, and an organic film layer 14 is formed by coating the AA region of the substrate. The material of the organic film layer 14 is OC (overcoat, photosensitive resin film) or PI (polyimide), etc.

[0130] S122: A diaphragm actuator 2 is formed on the lower side of the step area;

[0131] like Figure 3D As shown, the junction of the organic film layer 14 and the second substrate 13 is considered as a step region, where the organic film layer 14 is the higher side of the step, and the area of ​​the second substrate 13 that intersects with the organic film layer 14 is the lower side of the step. The corresponding thin film actuator 2 is patterned on the lower side. Its type is thermally responsive, and the optional material is polymethacrylic acid-b-polyN-isopropylacrylamide. The preparation method can be spin-coating or atomic layer deposition (ALD). The film thickness can be adjusted according to the defect situation, such as 1-10 μm.

[0132] S123: A cantilever beam material layer 32 is formed on the step region where the thin film actuator 2 is formed as a device layer 3, and a photoresist layer 4 is formed on the cantilever beam material layer 32;

[0133] like Figure 3D As shown, a cantilever beam material is deposited in the stepped region (including the higher side and the lower side where the thin-film actuator 2 is formed) to form device layer 3. The material can be aluminum (Al), and the deposition thickness is several hundred nanometers, such as 700 nm. After the device layer 3 is deposited, photoresist is coated, either by slot die or spin coating, with a thickness of 1.5 μm.

[0134] S22: Pre-bake the second substrate 13 to cause the thin film actuator 2 to expand and deform due to heat, pushing the cantilever beam material layer 32 on the thin film actuator 2 away from the functional layer 1, and making the cantilever beam material layer 32 on the thin film actuator 2 and the cantilever beam material layer 32 on the higher side of the step region tend to be on the same plane.

[0135] Specifically, pre-baking is performed at 110°C for 200 seconds. The thin-film actuator 2 undergoes rapid expansion and deformation due to the heat, with deformation ranging from a few micrometers to tens of micrometers. This causes the cantilever beam material layer 32 on the lower side of the step (at the substrate) to converge with the cantilever beam material layer 32 on the higher side of the step (at the organic film layer 14) to be on the same plane. Figure 3E As shown. Due to the slow thermal recovery rate of polymethacrylic acid-b-polyN-isopropylacrylamide, the film did not fully recover its original state after the substrate cooled down.

[0136] S32: Expose, develop, and bake the photoresist layer 4, and etch the cantilever beam material layer 32 to obtain the cantilever beam.

[0137] First, exposure is performed. At this time, the thin film actuator 2 remains in an expanded state, thereby providing focal plane compensation for the cantilever beam pattern on the lower side of the step area, ensuring the exposure effect.

[0138] Next, development is performed to wash away the exposed photoresist layer 4, followed by post-baking at 120°C for 200 seconds. Since the photoresist is not completely cured after development and still has some fluidity, post-baking keeps the thin-film actuator 2 in a state of thermal expansion, ensuring that the pattern is consistent with that during the exposure process.

[0139] Next, a patterned cantilever beam is obtained by etching.

[0140] In summary, complex micromechanical structures are often exposed simultaneously on film layers at different heights. Since the exposure process is planar, some patterns become out of focus and blurry. However, the thin-film actuator 2 in this embodiment compensates for the exposure focal plane through thermal micro-deformation, ensuring that the simultaneously exposed patterns are on the same focal plane and guaranteeing the exposure effect. Furthermore, because the film thickness of the device layer is relatively thin, even if there is uneven thickness at the boundary between the higher and lower sides of the step region due to the expansion of the thin-film actuator 2, it will not significantly affect the structural performance of the cantilever beam.

[0141] This embodiment is applicable to thin-film actuators 2 with large deformation (10μm~100μm).

[0142] Example 3: Preparation of suspended film bridges in a display panel.

[0143] The suspended membrane bridge structure in the display panel mainly includes anchor points, sacrificial support layers, and membrane bridges, such as... Figure 4A and Figure 4B As shown. During the fabrication of the suspended film bridge, a sacrificial layer 16 needs to be formed and then released. The release process can be wet etching or dry etching. Among them, due to the presence of liquid capillary forces and mechanical stirring, the suspended structure is prone to sticking to the substrate in the wet etching process, which may even cause device failure. Dry etching often uses oxygen plasma, HF or XeF2 gas, which has high equipment requirements, low co-directional etching efficiency, and is prone to damaging the upper metal film layer.

[0144] To solve the above problems, the solution adopted in this embodiment is as follows: Figure 4C As shown, it includes the following steps:

[0145] S131: A third substrate 15 is provided, and an anchor mechanism 17 and a sacrificial layer 16 are formed in the AA region of the third substrate 15. The third substrate 15 and the sacrificial layer 16 are functional layers 1.

[0146] Similarly, the third substrate 15 can be a glass substrate, and the sacrificial layer 16 can be made of silicon oxide, photoresist, or borosilicate glass (PSG). It can also be made of Si, Ge, polycrystalline silicon, etc. This embodiment uses photoresist as an example for illustration.

[0147] S132: A thin film actuator 2 is formed on the sacrificial layer 16;

[0148] The corresponding thin-film actuator 2 is graphically represented on the sacrificial layer 16, such as... Figure 4D As shown; the thin film actuator 2 in this embodiment is thermally responsive, and its material can be polymethyl methacrylate-b-polyN-isopropylacrylamide; the formation method can be spin-coating or atomic layer deposition (ALD), and the thickness can be adjusted according to the actual height of the sacrificial layer 16, such as 1-10 μm.

[0149] S133: A membrane bridge layer 33 is formed on the thin film actuator 2 and the anchor mechanism 17 as a device layer 3;

[0150] Specifically, aluminum (Al) can be deposited as the device layer 3 for the membrane bridge, with a deposition thickness of several hundred nanometers, such as 300 nm.

[0151] S23: Heat the third substrate 15 to cause the thin film actuator 2 to expand and deform due to heat, so that the sacrificial layer 16 is isolated from the membrane bridge layer 33;

[0152] S33: Release the sacrificial layer 16 so that the membrane bridge layer 33 and the anchor mechanism 17 form a suspended membrane bridge.

[0153] The sacrificial layer 16 can be released using either a wet or dry method. The key to releasing the sacrificial layer 16 lies in the selection ratio (corrosion rate ratio) of the release material and the structural layer material, as well as the subsequent drying of the free structure. In this embodiment, due to the presence of the thin-film actuator 2 above the sacrificial layer 16, during the heating and release process, the thermal expansion of the thin-film actuator 2 weakens the interfacial contact between the sacrificial layer 16 and the device layer 3, thus making it easier to release completely. Figure 4E As shown.

[0154] It should be noted that both wet and dry methods involve heating, which helps to accelerate the reaction rate. Therefore, step S23 can also be considered as a pre-process of step S33.

[0155] In this embodiment, a thin-film actuator 2 is fabricated on the surface of the support material of the sacrificial layer 16. Compared to growing only the sacrificial layer 16, the adhesion between the sacrificial layer 16 and the membrane bridge can be reduced, making it easier to release cleanly, and without adversely affecting the performance of the original device.

[0156] Example 4: Fabrication of a flexible radio frequency microelectromechanical system switch

[0157] The research on flexible radio frequency micro-electro-mechanical system (RF MEMS) switches aims to fabricate RF switches on flexible substrates. The core device structure is a movable three-dimensional microstructure, with key device dimensions all at the micrometer level. Due to limitations in the exposure capabilities of existing exposure machines, several key dimensions of the core device structure cannot be accurately patterned simultaneously. However, by adding a thin-film actuator layer, local exposure compensation can be performed at several locations of these key dimensions, ensuring that all key dimensions of the core device are achieved. The implementation principle of this embodiment is the same as that of Embodiment 2, and will not be repeated here.

[0158] In summary, the thin-film actuators involved in the above embodiments are single-layer or double-layer organic thin films. In semiconductor processes, organic thin films are usually used as insulating layers, serving as insulating media between stored charges and conductive metal lines. In actual production, the thickness of the insulating layer is usually around 1 micrometer. Therefore, the presence of the thin-film actuator will not have a significant impact on the device thickness or product performance.

[0159] The methods provided in the above embodiments are compatible with semiconductor processing technology and help to realize the preparation of three-dimensional fine structures. They are applicable to defect repair or auxiliary focusing of complex three-dimensional microstructure devices, including but not limited to: cantilever beams, resonant beams, membrane bridge structures, comb structures, movable suspended structures, MEMS RF switches, etc. They can improve the overall resolution of exposure patterns, simplify bonding processes, and improve product yield.

[0160] Based on the same inventive concept, in some alternative embodiments, a three-dimensional microstructure device is provided, comprising: a substrate, a thin-film actuator, and a three-dimensional microstructure; the thin-film actuator is located between the substrate and the three-dimensional microstructure, or inside the three-dimensional microstructure; the thin-film actuator expands during the formation of the three-dimensional microstructure device.

[0161] Based on the same inventive concept, in some alternative embodiments, a display panel is provided, the display panel including the three-dimensional microstructure device in the foregoing embodiments.

[0162] Based on the same inventive concept, in some alternative embodiments, a display device is provided, including the display panel in the foregoing embodiments.

[0163] In summary, the solutions provided by the embodiments of the present invention have the following beneficial effects or advantages:

[0164] This invention provides a display panel, a display device, a three-dimensional microstructure device, and a method for fabricating the same. The fabrication method involves forming a thin-film actuator between a functional layer and a device layer. Then, by setting a process, the thin-film actuator undergoes expansion and micro-deformation, causing the functional layer to move away from the device layer. In subsequent processing of the functional or device layers to fabricate the three-dimensional microstructure device, the expanded thin-film actuator can repair the uniformity of the functional layer film formation, compensate for exposure intensity distribution and exposure focal plane, and improve the isolation effect between the device layer and the functional layer. This improves the process precision of the three-dimensional micromechanical structure and ensures the performance and yield of the three-dimensional microstructure device and products manufactured using microelectromechanical systems (MEMS).

[0165] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0166] Similarly, it should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, this method of disclosure should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into this detailed description, wherein each claim itself is a separate embodiment of the invention.

[0167] Those skilled in the art will understand that modules in the apparatus of the embodiments can be adaptively changed and placed in one or more apparatuses different from that embodiment. Modules, units, or components in the embodiments can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components. Except where at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or apparatus so disclosed. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0168] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0169] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

Claims

1. A method for fabricating a three-dimensional microstructure device, characterized in that, The preparation method includes: A functional layer, a thin-film actuator, and a device layer are fabricated, wherein the thin-film actuator is located between the functional layer and the device layer; The thin-film actuator is expanded by performing a set process to move the functional layer away from the device layer; With the functional layer located away from the device layer, the device layer or the functional layer is processed to fabricate the three-dimensional microstructure device; The execution setting process causes the thin-film actuator to expand so that the functional layer is moved away from the device layer, including: The process of setting up the thin film actuator expands, pushing the contact area of ​​the device layer away from the functional layer, and making the contact area and the surrounding area tend to be on the same plane; The contact area is the area where the device layer contacts the thin-film actuator, and the peripheral area is the area where the device layer is connected to the contact area.

2. The preparation method according to claim 1, characterized in that, The material of the thin-film actuator is one of the following: thermally responsive shape memory material, photosensitive shape memory material, pH-induced shape memory material, electrosensitive shape memory material, and magnetosensitive shape memory material. The setting process is a corresponding process associated with the material of the thin film actuator; the corresponding process includes heating process, light irradiation process, pH adjustment process, electric field application process, and magnetic field application process.

3. The preparation method according to claim 2, characterized in that, The thermally responsive shape memory material is one of polyethylene-vinyl acetate, polyurethane, polycaprolactone, and their copolymers.

4. The preparation method according to claim 1, characterized in that, The fabrication of the functional layer, thin-film actuator, and device layer includes: The functional layer is prepared, and the recessed areas in the functional layer are detected; The thin-film actuator is formed within the recessed area; The device layer is formed on the functional layer on which the thin-film actuator is formed.

5. The preparation method according to claim 4, characterized in that, The three-dimensional microstructure device is the bottom electrode in the display panel; The step of preparing the functional layer and detecting the recessed areas in the functional layer includes: providing a first substrate, forming a dielectric layer on the first substrate, and detecting the recessed areas in the dielectric layer; wherein the first substrate and the dielectric layer constitute the functional layer. The step of forming the device layer on the functional layer on which the thin-film actuator is formed includes: An electrode material layer is formed on the functional layer on which the thin-film actuator is formed as the device layer, and a photoresist layer is formed on the electrode material layer; The execution setting process causes the thin-film actuator to expand, pushing the contact area of ​​the device layer away from the functional layer, and bringing the contact area and the surrounding area to the same plane, including: The first substrate is pre-baked to cause the thin film actuator to expand and deform due to heat, pushing the electrode material layer on the thin film actuator away from the functional layer, and making the electrode material layer on the thin film actuator and the electrode material layer in the peripheral area tend to be on the same plane. The process of fabricating the device layer or the functional layer to prepare the three-dimensional microstructure device, wherein the functional layer is located away from the device layer, includes: The photoresist layer is exposed, developed, and post-baked, and the electrode material layer is etched to obtain the bottom electrode.

6. The preparation method according to claim 1, characterized in that, The execution setting process causes the thin-film actuator to expand so that the functional layer is moved away from the device layer, including: The thin-film actuator is expanded by performing a set process to isolate the functional layer from the device layer.

7. The preparation method according to claim 6, characterized in that, The three-dimensional microstructure device is a suspended membrane bridge in the display panel; The fabrication of the functional layer, thin-film actuator, and device layer includes: A third substrate is provided, wherein an anchor mechanism and a sacrificial layer are formed in region AA of the third substrate, the third substrate and the sacrificial layer being the functional layer; a thin-film actuator is formed on the sacrificial layer; and a film bridge layer is formed on the thin-film actuator and the anchor mechanism as the device layer. The execution setting process causes the thin-film actuator to expand in order to isolate the functional layer from the device layer, including: The third substrate is heated to cause the thin film actuator to expand and deform, thereby isolating the sacrificial layer from the membrane bridge layer. The process of fabricating the device layer or the functional layer to prepare the three-dimensional microstructure device, wherein the functional layer is located away from the device layer, includes: Release the sacrificial layer so that the membrane bridge layer and the anchoring mechanism form the suspended membrane bridge.

8. A three-dimensional microstructure device, comprising: Substrate, thin-film actuator, and three-dimensional microstructure; The thin-film actuator is located between the substrate and the three-dimensional microstructure, or inside the three-dimensional microstructure; The thin-film actuator expands during the formation of the three-dimensional microstructure device; The thin-film actuator expands during the formation of the three-dimensional microstructure device, including: The process is executed to expand the thin film actuator, pushing the contact area of ​​the three-dimensional microstructure away from the substrate, and making the contact area and the surrounding area tend to be on the same plane; The contact area is the region where the three-dimensional microstructure contacts the thin-film actuator, and the peripheral area is the region where the three-dimensional microstructure is connected to the contact area.

9. A display panel, characterized in that, The display panel includes the three-dimensional microstructure device as described in claim 8.

10. A display device, characterized in that, Includes the display panel as described in claim 9.

Images