Fabrication method for micro-opto-electro-mechanical element
By employing anisotropic etching during the fabrication of MEMS lenses, a more symmetrical lens structure is formed, solving the problem of asymmetry in MEMS lens structures, improving optical performance, and reducing fabrication costs.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- CSMC TECH FAB2 CO LTD
- Filing Date
- 2025-07-11
- Publication Date
- 2026-06-25
AI Technical Summary
Existing MEMS lenses suffer from structural asymmetry, which leads to a decline in optical performance and limits their application in high-precision optical systems.
An anisotropic etching process is used to form a first groove on the substrate material layer, and a mask material layer is formed on the sidewall and bottom wall. The mask material on the bottom wall is removed by etching, and the mask material on the sidewall is retained as a mask for etching to form a second groove, thereby reducing the number of photolithography steps and avoiding overlay errors.
This improved the symmetry and optical performance of optical components, reduced manufacturing costs, and achieved higher alignment accuracy and optical performance.
Smart Images
Figure CN2025108041_25062026_PF_FP_ABST
Abstract
Description
Fabrication methods of microelectromechanical optical components
[0001] Cross-references to related applications
[0002] This application claims priority to Chinese Patent Application No. 202411868563.2, filed on December 17, 2024, entitled “Method for fabrication of microelectromechanical optical elements”, the entire contents of which are incorporated herein by reference for all purposes. Technical Field
[0003] This application relates to the field of microelectromechanical lens technology, and in particular to a method for fabricating a microelectromechanical optical element. Background Technology
[0004] MEMS (Micro Electro-Mechanical Systems) technology is a comprehensive technology based on microelectronics and microfabrication techniques. Its applications are wide-ranging, primarily encompassing inertial devices (such as accelerometers and gyroscopes), atomic force microscopes, data storage devices, three-dimensional microstructure fabrication, microvalves, micropumps, micronozzles, flow devices, micro-optical devices, packaging and bonding technologies, medical microdevices, experimental characterization devices, pressure sensors, microphones, and acoustic devices, among others.
[0005] Among these, micro-optical devices include optical components such as gating filters, thin-film filters, Fresnel lenses, refractive lenses, and grating mirrors. In related technologies, lenses fabricated using MEMS technology suffer from structural asymmetry, which directly leads to a decrease in the lens's optical performance (such as image quality and focusing accuracy), limiting its application in high-precision optical systems. Summary of the Invention
[0006] Therefore, it is necessary to provide a method for fabricating microelectromechanical optical components to address the above-mentioned problems.
[0007] To achieve the above objectives, in a first aspect, embodiments of this application provide a method for fabricating a microelectromechanical optical element, comprising:
[0008] Provide substrate;
[0009] A matrix material layer is formed on the substrate;
[0010] A first groove is formed on the substrate material layer;
[0011] A second mask material layer is formed on the bottom wall and side wall of the first groove;
[0012] The second mask material layer is etched using an anisotropic etching process to remove the second mask material layer located on the bottom wall of the first groove, while retaining the second mask material layer located on the side wall of the first groove.
[0013] The exposed area of the bottom wall of the first groove is etched to form the second groove;
[0014] Lens layers are formed in the first groove and the second groove.
[0015] The method for fabricating a microelectromechanical optical element provided in this application involves first forming a first groove on a substrate material layer, then forming a second mask material layer on the sidewalls and bottom wall of the first groove. Next, an anisotropic etching process is used to remove the second mask material layer on the bottom wall of the first groove, leaving the second mask material layer on the sidewalls of the first groove. Then, using the retained second mask material layer as a mask, etching is performed on the exposed area of the first groove to form a second groove, followed by the formation of a lens layer. During the formation of the second groove, a step is formed in the area covered by the second mask material layer. Compared to traditional techniques that use multiple photolithography steps for overlay, the fabrication method provided in this application eliminates the need for overlay, thus avoiding overlay errors and improving the alignment accuracy between the first and second grooves. This results in higher symmetry of the optical element and improved optical performance. Furthermore, it reduces the number of photolithography steps, lowering the fabrication cost.
[0016] In one embodiment, the anisotropic etching process includes plasma etching and reactive ion etching.
[0017] In one embodiment, the step of forming the first groove on the substrate material layer includes:
[0018] A first mask material layer is formed on the substrate material layer;
[0019] The first mask material layer is patterned to form the first mask layer;
[0020] The exposed area of the substrate material layer is etched to form the first groove.
[0021] In one embodiment, the first mask material layer and the second mask material layer are made of the same material.
[0022] In one embodiment, the step of patterning the first mask material layer to form the first mask layer includes:
[0023] Photoresist is formed on the first mask material layer;
[0024] The photoresist is exposed and developed;
[0025] The first mask material layer is etched to form the first mask layer;
[0026] Remove the photoresist.
[0027] In one embodiment, after etching the exposed area of the bottom wall of the first groove to form the second groove, and before forming the lens layer in the first groove and the second groove, the method further includes:
[0028] Remove the first mask material layer and the second mask material layer.
[0029] In one embodiment, the step of forming a lens layer within the first groove and the second groove includes:
[0030] Lens material layers are filled into the first and second grooves;
[0031] The lens material layer is planarized to form the lens layer.
[0032] In one embodiment, the distance between the orthographic projection of the first groove on the substrate and the orthographic projection of the second groove on the substrate is a first spacing, the first spacing being equal to the thickness of the second mask material layer on the sidewall of the first groove.
[0033] In one embodiment, after the step of etching the exposed area of the bottom wall of the first groove to form the second groove, and before the step of forming a lens layer in the first groove and the second groove, the method further includes:
[0034] A third mask material layer is formed on the bottom wall and side wall of the second groove;
[0035] The third mask material layer is etched using an anisotropic etching process to remove the third mask material layer located on the bottom wall of the second groove, while retaining the third mask material layer located on the side wall of the second groove.
[0036] The exposed area of the bottom wall of the second groove is etched to form the third groove.
[0037] Secondly, embodiments of this application provide another method for fabricating microelectromechanical optical elements, including:
[0038] Provide substrate;
[0039] A matrix material layer is formed on the substrate;
[0040] A groove is formed on the substrate material layer;
[0041] A mask material layer is formed on the bottom wall and side wall of the groove; the mask material layer is etched using an anisotropic etching process to remove the mask material layer located on the bottom wall and retain the mask material layer located on the side wall; the exposed area of the bottom wall of the groove is etched; wherein, this step is repeated multiple times to form a groove structure with multiple steps;
[0042] A lens layer is formed within the groove structure.
[0043] The fabrication method for microelectromechanical optical elements provided in this application involves first forming a groove on a substrate material layer, then forming a mask material layer on the sidewalls and bottom wall of the groove. Next, an anisotropic etching process is used to remove the mask material layer on the bottom wall of the groove, while retaining the mask material layer on the sidewalls. Then, using the retained mask material layer as a mask, etching is performed on the exposed area of the groove, repeating this process multiple times until a groove structure with multiple steps is formed. Finally, a lens layer is formed. During the formation of the groove, steps are formed in the area covered by the mask material layer. Compared to traditional techniques that use multiple photolithography steps for overlay, the fabrication method provided in this application eliminates the need for overlay, thus avoiding overlay errors and improving the alignment accuracy of the grooves in all processes. This results in higher symmetry of the optical element and improved optical performance. Furthermore, it reduces the number of photolithography steps, lowering the fabrication cost. Attached Figure Description
[0044] To more clearly illustrate the technical solutions in the embodiments or exemplary embodiments of this application, the drawings used in the description of the embodiments or exemplary embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0045] Figure 1 is a schematic flowchart of a method for fabricating a microelectromechanical optical element according to an embodiment of this application.
[0046] Figures 2-14 are cross-sectional schematic diagrams of the components during the fabrication process shown in Figure 1.
[0047] Figure 15 is a schematic diagram of another process for fabricating a microelectromechanical optical element according to an embodiment of this application.
[0048] Explanation of reference numerals in the attached figures: 10, substrate; 20, base material layer; 21, first groove; 22, second groove; 23, third groove; 24, groove structure; 30, first mask material layer; 31, first mask layer; 40, photoresist; 50, second mask material layer; 51, second mask layer; 60, third mask material layer; 61, third mask layer; 70, lens material layer; 71, lens layer. Detailed Implementation
[0049] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.
[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
[0051] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, parts, regions, layers, doping types, and / or portions, these elements, parts, regions, layers, doping types, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, part, region, layer, doping type, or portion from another element, part, region, layer, doping type, or portion. Therefore, without departing from the teachings of this application, the first element, component, region, layer, doping type, or portion discussed below may be represented as a second element, component, region, layer, or portion; for example, the first doping type may be referred to as the second doping type, and similarly, the second doping type may be referred to as the first doping type; the first doping type and the second doping type are different doping types, for example, the first doping type may be P-type and the second doping type may be N-type, or the first doping type may be N-type and the second doping type may be P-type.
[0052] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.
[0053] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, in this specification, the term “and / or” includes any and all combinations of the associated listed items.
[0054] Embodiments of the application are described herein with reference to cross-sectional views illustrating ideal embodiments (and intermediate structures), thus allowing for the expectation of variations in the illustrated shapes due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of the application should not be limited to the specific shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing techniques. For instance, implantation regions shown as rectangular typically have rounded or curved features at their edges and / or implantation concentration gradients, rather than a binary change from implantation regions to non-implantation regions. Similarly, buried regions formed by implantation can result in some implantation in the region between the buried region and the surface traversed during implantation. Therefore, the regions shown in the figures are substantially schematic, and their shapes do not represent the actual shapes of regions of the device and do not limit the scope of the application.
[0055] In traditional techniques, lens structures are fabricated using a multi-stage photolithography process. Specifically, a first photolithography layer is applied to the substrate layer, followed by etching to form pits; then a second photolithography layer is applied, followed by etching to form smaller pits; then a third photolithography layer is applied, followed by etching to form even smaller pits, thus creating stepped pits. Finally, lens material is filled into these stepped pits to form the lens structure.
[0056] However, there are often discrepancies in the overlay between different lithography techniques. Overlay discrepancies can lead to an asymmetrical structure in the lens, which prevents the light from propagating along the intended path and thus affects the lens's performance.
[0057] In view of this, embodiments of this application provide a method for fabricating a microelectromechanical optical element that can improve the performance of optical elements.
[0058] In a first aspect, referring to Figure 1 and in conjunction with Figures 2-14, embodiments of this application provide a method for fabricating a microelectromechanical optical element, specifically including the following steps:
[0059] S10: Provide a substrate 10. The substrate 10 may be a semiconductor material or a non-semiconductor material, wherein the semiconductor material is, for example: single crystal silicon, polycrystalline silicon, amorphous silicon, germanium silicon compound, silicon-on-insulator (SOI) or low temperature poly-silicon (LTPS), etc.
[0060] S20: A substrate material layer 20 is formed on the substrate 10. The structure of the substrate material layer 20 after formation is shown in Figure 2. Exemplarily, the material of the substrate material layer 20 may include at least one of silicon nitride, silicon oxide, and silicon oxynitride. The substrate material layer 20 may be formed by chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), or any other suitable method.
[0061] S30: A first groove 21 is formed on the substrate material layer 20. The structure of the first groove 21 after its formation is shown in Figure 6.
[0062] S40: A second mask material layer 50 is formed on the bottom wall and sidewalls of the first groove 21. The structure of the second mask material layer 50 after formation is shown in Figure 7. Exemplarily, the second mask material layer 50 can be formed by chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), or any other suitable method.
[0063] S50: An anisotropic etching process is used to etch the second mask material layer 50 to remove the second mask material layer 50 located on the bottom wall of the first groove 21, while retaining the second mask material layer 50 located on the side wall of the first groove 21. After etching the second mask material layer 50, a second mask layer 51 is formed, which covers the side wall of the first groove 21 and part of the bottom wall of the first groove 21.
[0064] S60: The exposed area of the bottom wall of the first groove 21 is etched to form the second groove 22. The structure of the second groove 22 after its formation is shown in Figure 8. The inner diameter of the second groove 22 is D2, and the inner diameter of the first groove 21 is D1, where D2 is smaller than D1. A step is formed between the sidewall of the second groove 22 and the sidewall of the first groove 21.
[0065] S70: A lens layer 71 is formed in the first groove 21 and the second groove 22. The structure of the lens layer 71 after its formation is shown in Figure 14.
[0066] In this embodiment, a first groove 21 is first formed on the substrate material layer 20. Then, a second mask material layer 50 is formed on the sidewalls and bottom wall of the first groove 21. Next, an anisotropic etching process is used to remove the second mask material layer 50 on the bottom wall of the first groove 21, leaving the second mask material layer 50 on the sidewalls of the first groove 21. Then, using the retained second mask material layer 50 (e.g., second mask layer 51) as a mask, etching is performed on the exposed area of the first groove 21 to form a second groove 22. Finally, a lens layer 71 is formed. During the formation of the second groove 22, a step is formed in the area covered by the retained second mask material layer 50 (e.g., second mask layer 51). Compared to traditional techniques that use multiple photolithography processes for overlay, the fabrication method provided in this application eliminates the need for overlay, thereby avoiding overlay errors and improving the alignment accuracy between the first groove 21 and the second groove 22. This results in higher symmetry of the optical element and improved optical performance. Furthermore, it only requires one photolithography step, reducing the number of photolithography steps and lowering the fabrication cost.
[0067] It should be noted that in this embodiment, only two steps are formed on the substrate material layer 20. If more steps are needed, further etching can be performed on the bottom wall of the second groove 22 before filling the lens material to form more steps. It is understood that anisotropic etching or photolithography can be used in this process, and this embodiment does not impose any particular limitation on this.
[0068] In one embodiment, the anisotropic etching process includes plasma etching and reactive ion etching. This approach helps reduce costs and etching difficulty while also ensuring etching uniformity.
[0069] Specifically, plasma etching utilizes a radio frequency (RF) power source to ionize reactive gases and form plasma. The plasma contains various reactive particles, such as ions, electrons, and free radicals. Under the influence of an electric field, positively charged ions accelerate and bombard the surface of the material being etched. These ions are directional, causing etching to primarily occur along directions perpendicular to the material surface, thus achieving anisotropic etching.
[0070] Reactive ion etching (RIE) combines physical bombardment with chemical reactions to achieve anisotropic etching. By adjusting the radio frequency (RF) power, the energy and directionality of the ions can be controlled. During etching, the reactive gas is ionized, and the ions are accelerated towards the surface of the material under the influence of an electric field, simultaneously reacting chemically with the surface. For example, in etching silicon dioxide, the reactive gas is trifluoromethane. Trifluoromethane decomposes in plasma to produce fluoride ions and other reactive free radicals. These fluoride ions bombard the silicon dioxide surface perpendicularly, reacting with silicon and oxygen atoms to generate SiF4 and other volatile products. This synergistic effect of physical and chemical processes results in highly anisotropic etching.
[0071] It is understood that other processes can also be used to achieve anisotropic etching, and the embodiments of this application are not particularly limited here.
[0072] In one embodiment, the distance between the orthographic projection of the outer contour of the first groove 21 on the substrate 10 and the orthographic projection of the outer contour of the second groove 22 on the substrate 10 is a first spacing, which is equal to the thickness of the second mask material layer 50 on the sidewall of the first groove 21. Specifically, referring to Figures 6 and 8, the inner diameter of the second groove 22 is D2, the inner diameter of the first groove 21 is D1, and half the difference between D1 and D2 is equal to the first spacing and equal to the thickness of the second mask material layer 50 on the sidewall of the first groove 21.
[0073] In traditional fabrication methods, the first spacing is determined by the overlay of two photolithography steps, and there is an overlay deviation between the two steps; for example, the first spacing is larger on one side and smaller on the other. In this embodiment, the first spacing is determined by the thickness of the second mask material layer 50, which is equivalent to achieving self-alignment. Furthermore, the deposition thickness accuracy of the film layer is relatively easy to control, while the overlay accuracy of the photolithography machine is more difficult to control. Therefore, this embodiment is beneficial for achieving better uniformity of the first spacing, thereby increasing the symmetry of the optical element. In addition, to achieve higher overlay accuracy, a more expensive photolithography machine must be used, while this embodiment can achieve higher accuracy at a lower cost.
[0074] In one embodiment, S30: forming a first groove 21 on the substrate material layer 20 specifically includes the following steps:
[0075] S31: A first mask material layer 30 is formed on the substrate material layer 20. The structure of the first mask material layer 30 after its formation is shown in FIG3. Exemplarily, the first mask material layer 30 can be formed by chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), or any other suitable method.
[0076] S32: The first mask material layer 30 is patterned to form the first mask layer 31. The structure of the first mask layer 31 after formation is shown in Figure 5.
[0077] S33: Etch the exposed area of the substrate material layer 20 to form a first groove 21. For example, a plasma etching process can be used to etch the substrate material layer 20.
[0078] In one embodiment, the first mask material layer 30 and the second mask material layer 50 are made of the same material. This helps to reduce costs.
[0079] In one embodiment, S32: The first mask material layer 30 is patterned to form the first mask layer 31, specifically including the following steps:
[0080] S321: Photoresist 40 is formed on the first mask material layer 30.
[0081] S322: Expose and develop the photoresist 40.
[0082] S323: Etch the first mask material layer 30 to form the first mask layer 31. The structure after this step is completed is shown in Figure 4.
[0083] S324: Remove photoresist 40. The structure after removing photoresist 40 is shown in Figure 5. It can be understood that photoresist 40 can be removed by either a dry process or a wet process.
[0084] In one embodiment, after S60: etching the exposed area of the bottom wall of the first groove 21 to form the second groove 22, and before S70: forming the lens layer 71 in the first groove 21 and the second groove 22, the following steps are further included:
[0085] S64: Remove the first mask material layer 30 and the second mask material layer 50. Specifically, remove the first mask layer 31 and the second mask layer 51. It is understood that the mask materials can be removed by a dry process or a wet process.
[0086] In one embodiment, S70: Forming a lens layer 71 in the first groove 21 and the second groove 22 specifically includes the following steps:
[0087] S71: A lens material layer 70 is filled into the first groove 21 and the second groove 22. Exemplarily, the lens material layer 70 may include at least one of silicon nitride, silicon oxide, and silicon oxynitride. The lens material layer 70 may be formed by chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), or any other suitable method. Specifically, as shown in FIG13, the lens material layer 70 not only fills the first groove 21 and the second groove 22 but also covers the surface of the substrate material layer 20.
[0088] S72: The lens material layer 70 is planarized to form the lens layer 71. Specifically, the lens material layer 70 is planarized by a chemical-mechanical polishing (CMP) process.
[0089] In one embodiment, after S60: etching the exposed area of the bottom wall of the first groove 21 to form the second groove 22, and before S70: forming the lens layer 71 in the first groove 21 and the second groove 22, the following steps are further included:
[0090] S61: A third mask material layer 60 is formed on the bottom wall and sidewalls of the second groove 22. The structure of the third mask material layer 60 after formation is shown in Figure 9. Exemplarily, the third mask material layer 60 can be formed by chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), or any other suitable method.
[0091] S62: An anisotropic etching process is used to etch the third mask material layer 60 to remove the third mask material layer 60 located on the bottom wall of the second groove 22, while retaining the third mask material layer 60 located on the side wall of the second groove 22. After etching the third mask material layer 60, a third mask layer 61 is formed, which covers the side wall of the second groove 22 and part of the bottom wall of the second groove 22.
[0092] S63: The exposed area of the bottom wall of the second groove 22 is etched to form the third groove 23. The structure of the third groove 23 after formation is shown in Figure 11. A step is formed between the sidewall of the third groove 23 and the sidewall of the second groove 22. The distance between the outer contour of the orthographic projection of the second groove 22 on the substrate 10 and the outer contour of the orthographic projection of the third groove 23 on the substrate 10 is the second spacing, which is equal to the thickness of the third mask material layer 60 on the sidewall of the second groove 22. Specifically, referring to Figures 8 and 11, the inner diameter of the third groove 23 is D3, the inner diameter of the second groove 22 is D2, and half the difference between D2 and D3 is equal to the second spacing and equal to the thickness of the third mask material layer 60 on the sidewall of the second groove 22.
[0093] In the embodiments of the application, the second spacing is determined by the thickness of the third mask material layer 60, which is equivalent to achieving self-alignment. Furthermore, the deposition thickness accuracy of the film layer is relatively easy to control, while the overlay accuracy of the lithography machine is relatively difficult to control. Therefore, the embodiments of this application are beneficial to making the uniformity of the second spacing better, and at the same time making the repeatability of the fabrication process better.
[0094] It should be noted that in this embodiment, only three steps are formed on the substrate material layer 20. If more steps are needed, further etching can be performed on the bottom wall of the third groove 23 before filling the lens material to form more steps. It is understood that anisotropic etching or photolithography can be used in this process, and this embodiment does not impose any particular limitation on this.
[0095] It is understandable that when a third mask material layer 60 is formed on the sidewall of the second groove 22, the first mask material layer 30, the second mask material layer 50 and the third mask material layer 60 can be removed simultaneously in S64.
[0096] In one embodiment, the first mask material layer 30, the second mask material layer 50, and the third mask material layer 60 are all made of the same material. This helps to reduce costs. For example, the materials of the first mask material layer 30, the second mask material layer 50, and the third mask material layer 60 may include silicon nitride and silicon oxide.
[0097] It should be noted that the thickness of the second mask material layer 50 and the thickness of the third mask material layer 60 can be the same or different, and this application embodiment does not limit this.
[0098] Secondly, referring to FIG15, this application provides another method for fabricating a microelectromechanical optical element, specifically including the following steps:
[0099] S100: Provides substrate 10.
[0100] S200: A substrate material layer 20 is formed on the substrate 10.
[0101] S300: A groove is formed on the substrate material layer 20.
[0102] S400: A mask material layer is formed on the bottom wall and side wall of the groove; the mask material layer is etched using an anisotropic etching process to remove the mask material layer on the bottom wall and retain the mask material layer on the side wall; the exposed area of the bottom wall of the groove is etched; wherein, this step is repeated multiple times to form a groove structure 24 with multiple steps.
[0103] S500: A lens layer 71 is formed within the groove structure 24.
[0104] The fabrication method of the microelectromechanical optical element provided in this application embodiment first forms a groove on a substrate material layer 20, then forms a mask material layer on the sidewall and bottom wall of the groove, then uses an anisotropic etching process to etch the mask material layer on the bottom wall of the groove, leaving the mask material layer on the sidewall of the groove intact, then uses the retained mask material layer as a mask to etch the exposed area of the groove, repeating this process multiple times until a groove structure 24 with multiple steps is formed, and then a lens layer 71 is formed. During the process of forming the groove, steps are formed in the area covered by the mask material layer. Compared with the traditional technology that uses multiple photolithography steps for overlay, the fabrication method provided in this application embodiment eliminates the need for overlay, thus avoiding overlay errors, improving alignment accuracy, and resulting in higher symmetry and improved optical performance of the optical element; furthermore, it reduces the number of photolithography steps, lowering the fabrication cost.
[0105] It should be noted that the specific processes of each step in the second aspect embodiment may be the same as those of each step in the first aspect embodiment, and will not be repeated here.
[0106] In the description of this specification, the references to terms such as "some embodiments," "other embodiments," "ideal embodiments," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example that are included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.
[0107] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features of the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0108] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A method for fabricating a microelectromechanical optical element, characterized in that, include: Provide substrate; A matrix material layer is formed on the substrate; A first groove is formed on the substrate material layer; A second mask material layer is formed on the bottom wall and side wall of the first groove; The second mask material layer is etched using an anisotropic etching process to remove the second mask material layer located on the bottom wall of the first groove, while retaining the second mask material layer located on the side wall of the first groove. The exposed area of the bottom wall of the first groove is etched to form the second groove; Lens layers are formed in the first groove and the second groove.
2. The method for fabricating a microelectromechanical optical element according to claim 1, characterized in that, The anisotropic etching process includes plasma etching and reactive ion etching.
3. The method for fabricating a microelectromechanical optical element according to claim 1, characterized in that, The step of forming the first groove on the substrate material layer includes: A first mask material layer is formed on the substrate material layer; The first mask material layer is patterned to form the first mask layer; The exposed area of the substrate material layer is etched to form the first groove.
4. The method for fabricating a microelectromechanical optical element according to claim 3, characterized in that, The first mask material layer and the second mask material layer are made of the same material.
5. The method for fabricating a microelectromechanical optical element according to claim 3, characterized in that, The step of patterning the first mask material layer to form the first mask layer includes: Photoresist is formed on the first mask material layer; The photoresist is exposed and developed; The first mask material layer is etched to form the first mask layer; Remove the photoresist.
6. The method for fabricating a microelectromechanical optical element according to claim 3, characterized in that, After etching the exposed area of the bottom wall of the first groove to form the second groove, and before forming the lens layer in the first groove and the second groove, the method further includes: Remove the first mask material layer and the second mask material layer.
7. The method for fabricating a microelectromechanical optical element according to claim 1, characterized in that, The step of forming a lens layer in the first groove and the second groove includes: Lens material layers are filled into the first and second grooves; The lens material layer is planarized to form the lens layer.
8. The method for fabricating a microelectromechanical optical element according to claim 1, characterized in that, The distance between the orthographic projection of the first groove on the substrate and the orthographic projection of the second groove on the substrate is a first spacing, which is equal to the thickness of the second mask material layer on the sidewall of the first groove.
9. The method for fabricating a microelectromechanical optical element according to claim 1, characterized in that, After the step of etching the exposed area of the bottom wall of the first groove to form the second groove, and before the step of forming a lens layer in the first groove and the second groove, the method further includes: A third mask material layer is formed on the bottom wall and side wall of the second groove; The third mask material layer is etched using an anisotropic etching process to remove the third mask material layer located on the bottom wall of the second groove, while retaining the third mask material layer located on the side wall of the second groove. The exposed area of the bottom wall of the second groove is etched to form the third groove.
10. A method for fabricating a microelectromechanical optical element, characterized in that, include: Provide substrate; A matrix material layer is formed on the substrate; A groove is formed on the substrate material layer; A masking material layer is formed on the bottom and side walls of the groove; The mask material layer is etched using an anisotropic etching process to remove the mask material layer located on the bottom wall and retain the mask material layer located on the side wall; The exposed area of the bottom wall of the groove is etched; this step is repeated multiple times to form a groove structure with multiple steps. A lens layer is formed within the groove structure.