Elastically supported micromirror unit and micromirror array and manufacturing method thereof

Abstract

The present invention discloses an elastically supported micromirror unit and micromirror array, and a manufacturing method. The micromirror unit comprises: a microbridge structure disposed on a substrate, the microbridge structure having a microbridge deck, the microbridge deck being elastically supported on the substrate via at least three elastic supports, the micromirror surface being disposed on the microbridge deck and isolated from the supports; a force-applying mechanism disposed on the substrate, which applies a force to at least one of the supports, causing it to elastically stretch or compress in height, thereby causing the microbridge deck and the micromirror surface to deflect in corresponding directions and angles. The present invention can reduce the pull-in voltage required to drive the micromirrors, can be implemented using technology fully compatible with CMOS processes, and can significantly improve product performance and reduce costs.

Description

Technical Field

[0001] The present invention relates to the field of micro-electromechanical systems (MEMS) and semiconductor process technology, and in particular to an elastically supported micromirror unit and a micromirror array and a manufacturing method thereof. Background Art

[0002] MEMS mirrors are a hot topic among MEMS products, with a wide range of applications, including optical communications, 3D cameras, and projectors. In recent years, they have become a crucial component in automotive LiDAR (LiDAR). With the advancement of autonomous driving technology, market demand for MEMS mirrors is increasing, placing higher demands on their technology.

[0003] Existing MEMS micromirror products generally use electrostatic force, thermal stress, electromagnetic force, and other solutions to control the rotation of the micromirror, and the corresponding control structure is formed through MEMS technology. However, the commonly used micromirror structures in the industry are difficult to manufacture because they are difficult to be compatible with standard CMOS processes and cannot effectively utilize the advanced equipment and process technology of CMOS processes, resulting in relatively large sizes. At the same time, the rotation angle of traditional single large-scale micromirror structures requires a large cavity structure to match it, so the substrate under the entire micromirror is generally completely removed to meet product requirements. However, this greatly increases the process complexity of the product.

[0004] In addition, existing MEMS micromirror products usually use a torsion arm with fixed supports at both ends to support the micromirror surface, and often adopt an electrostatic drive mode to drive the micromirror to rotate around the torsion arm to achieve control of the micromirror's rotation angle. Because the two ends of the torsion arm are fixedly supported on the anchor point, when using electrostatic drive to rotate the micromirror surface, it is necessary to overcome the stiffness of the torsion arm structure, which results in a higher pull-in voltage required to drive the micromirror. In addition, the use of a torsion arm with fixed supports at both ends to support the micromirror surface means that the micromirror can only rotate in one direction (i.e., around the torsion arm), so its function is relatively simple. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and to provide a micromirror unit and a micromirror array with elastic support and a manufacturing method thereof.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] The present invention provides an elastically supported micromirror unit, comprising:

[0008] A microbridge structure provided on a substrate, wherein the microbridge structure is provided with a microbridge deck, the microbridge deck being elastically supported on the substrate by at least three elastic supports, and a micromirror surface being provided on the microbridge deck, the micromirror surface being isolated from the support body;

[0009] In which, a force-applying mechanism is provided on the substrate, and a force is applied to at least one of the supporting bodies through the force-applying mechanism, causing it to undergo corresponding elastic stretching or compression in height, thereby driving the micro-bridge bridge surface and the micro-mirror surface to deflect in corresponding directions and angles.

[0010] Furthermore, the force applying mechanism includes an electrostatic force applying mechanism for applying an electrostatic force to at least one of the supporting bodies.

[0011] Furthermore, the electrostatic force applying mechanism includes a first electrode provided on the surface of the substrate and surrounding the support body, and a second electrode provided on the bridge surface of the microbridge and connected to the support body. The first electrode and the second electrode form a capacitor structure for applying an electrostatic force to the support body, and the micromirror surface is electrically isolated from the second electrode.

[0012] Furthermore, the first electrode is connected to a control circuit provided in the substrate, and the second electrode is connected to the control circuit through the conductive support body. The control circuit is used to apply an electrostatic force to at least one of the support bodies through the first electrode and the second electrode.

[0013] Furthermore, the lower end of the support body is connected to the control circuit through a landing metal structure provided on the surface of the substrate, the first electrode is arranged around the landing metal structure and is electrically isolated from the landing metal structure, and the support body is connected to the middle part of the bottom surface of the second electrode through the upper end.

[0014] Furthermore, the microbridge deck includes a quadrilateral, and the four supporting bodies are respectively arranged on the four corners of the quadrilateral of the microbridge deck. The upper end of each supporting body is connected to a second electrode arranged on the microbridge deck, and the lower end of each supporting body is correspondingly connected to a landing metal structure arranged on the substrate surface. Each landing metal structure is surrounded by a ring-shaped first electrode located on the substrate surface and corresponding to the second electrode above. The micromirror surface is located on the microbridge deck outside each second electrode, and is electrically isolated from each second electrode and the supporting body.

[0015] Furthermore, the support body includes a spring structure having elasticity along its height direction.

[0016] Furthermore, the spring structure includes a plurality of conductive vertical support segments and horizontal support segments, and the vertical support segments and the horizontal support segments are alternately connected to form an elastic turning structure in the height direction of the support body.

[0017] The present invention further provides a micromirror array comprising the elastically supported micromirror units described above, wherein the micromirror units are sequentially arranged in rows and columns on the same substrate to form the elastically supported micromirror array.

[0018] Furthermore, a dedicated integrated circuit is provided in the substrate, and a control circuit is provided in the dedicated integrated circuit, which is used to apply a force to at least one support body on each of the micromirror units through a force-applying mechanism provided on each of the micromirror units, causing the micromirror units to undergo corresponding elastic extension or compression in height, thereby driving the microbridge surface and the micromirror surface of each of the micromirror units to independently deflect in corresponding directions and angles. The micromirror array has an occupied area on the substrate corresponding to the dedicated integrated circuit.

[0019] The present invention also provides a method for manufacturing an elastically supported micromirror unit, comprising:

[0020] providing a substrate;

[0021] forming a first electrode metal layer on the surface of the substrate and patterning the layer to form at least three landing metal structures and a first electrode surrounding each of the landing metal structures;

[0022] forming a sacrificial layer on the surface of the substrate to cover the landing metal structure and the first electrode;

[0023] forming a metal support body having a turning structure corresponding to each of the landing metal structures in the sacrificial layer, such that the lower end of the support body is connected to the top surface of the landing metal structure and the upper end of the support body is exposed from the surface of the sacrificial layer;

[0024] forming a dielectric layer pattern covering the upper end of the support body on the surface of the sacrificial layer, and forming an opening on the dielectric layer pattern corresponding to the upper end of the support body;

[0025] forming a second electrode metal layer on the surface of the sacrificial layer, covering the dielectric layer pattern and patterning the second electrode corresponding to the first electrode and connected to the upper end of the support body through the opening on the dielectric layer pattern surface, and isolating the micromirror surfaces between the second electrodes, thereby forming a microbridge bridge surface;

[0026] The sacrificial layer is removed to release the microbridge structure formed by the microbridge bridge surface and the support body, thereby forming the microbridge bridge surface and the micromirror surface elastically supported on the substrate by the support body.

[0027] Furthermore, forming a sacrificial layer on the surface of the substrate to cover the landing metal structure and the first electrode, and forming a metal support body having a turning structure corresponding to each landing metal structure in the sacrificial layer, so that the lower end of the support body is connected to the top surface of the landing metal structure and the upper end of the support body is exposed from the surface of the sacrificial layer, specifically includes:

[0028] forming multiple sacrificial layers in sequence on the surface of the substrate to cover the landing metal structure and the first electrode;

[0029] Alternately forming connected metal vertical support segments and metal horizontal support segments corresponding to each of the landing metal structures in the sacrificial layers of each layer;

[0030] Among them, the lower end of the vertical support segment located in the lowest sacrificial layer is connected to the top surface of the landing metal structure, the upper end of the vertical support segment located in the highest sacrificial layer is exposed from the surface of the highest sacrificial layer, and the two vertical support segments located in the upper and lower layers of any one layer of horizontal support segments are respectively arranged on the upper and lower surfaces of the two opposite ends of the horizontal support segments of that layer, thereby forming a metal support body with a turning structure corresponding to each landing metal structure in the sacrificial layer, which is composed of multiple vertical support segments and multiple horizontal support segments alternately connected, so that the support body is connected to the top surface of the landing metal structure through the lower end of the vertical support segment located in the lowest sacrificial layer, and the support body is exposed from the surface of the sacrificial layer through the upper end of the vertical support segment located in the highest sacrificial layer.

[0031] It can be seen from the above technical solution that the present invention adopts at least three elastic supports on the microbridge structure to elastically support the microbridge surface provided with the micromirror surface on the substrate, and applies a force (such as electrostatic force) to at least one of the supports through a force-applying mechanism, so that it elastically stretches or compresses in height, thereby driving the microbridge surface and the micromirror surface to deflect (rotate) in corresponding directions and angles. Not only can the force applied to each elastic support body be used to stabilize the micromirror surface and deflect it in any direction and at different angles, but the elastic force of the support body can also be used to reduce the driving force of the micromirror when adjusting the deflection of the micromirror surface. The pull-in voltage required for driving the micromirror is reduced, thereby significantly improving the problem of high pull-in voltage required for driving the micromirror caused by the existing method of using a torsion arm with double-end fixed support to support the micromirror; moreover, the structure of the micromirror unit of the present invention is simple, and can be miniaturized by using a technology that is fully compatible with the CMOS process, and the required cavity height is limited at the same deflection angle, which not only significantly reduces the process complexity of the product, but also enables the micromirror array composed of the micromirror units to be directly implemented on a substrate (such as a silicon wafer) with an ASIC circuit (application-specific integrated circuit) and can share area with the ASIC circuit, thereby significantly improving product performance and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of an elastically supported micromirror unit according to a preferred embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of a top view of a microbridge deck according to a preferred embodiment of the present invention;

[0034] Figure 3 This is a schematic structural diagram of a first electrode according to a preferred embodiment of the present invention;

[0035] Figure 4-11 The figure is a process flow diagram of a method for manufacturing an elastically supported micromirror unit according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with ordinary skills in the field to which the invention belongs. The words "including" and similar words used in this article mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0037] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0038] See also Figure 1 , Figure 1 FIG. 1 is a structural diagram of an elastically supported micromirror unit according to a preferred embodiment of the present invention. Figure 1 As shown, an elastically supported micromirror unit of the present invention includes a microbridge structure established on a substrate 10. The microbridge structure has a microbridge deck 20, which is elastically supported on the substrate 10 by at least three elastic supports 30. A micromirror surface 23 is provided on the microbridge deck 20, and the micromirror surface 23 is disposed on the microbridge deck 20 in isolation from the supports 30.

[0039] The micromirror unit is also provided with a force-applying mechanism, which is disposed on the substrate 10. The force-applying mechanism applies a force to at least one of the supports 30, causing it to elastically stretch or compress in height, thereby causing the microbridge deck 20 and the micromirror surface 23 to deflect (tilt) in the corresponding direction and angle.

[0040] In some embodiments, the force applying mechanism may include an electrostatic force applying mechanism for applying an electrostatic force to at least one of the supports 30 .

[0041] See also Figure 1 In conjunction with Figure 2-Figure 3 The microbridge deck 20 is a quadrilateral and has four supports 30. This example is provided for illustration, but is not limited thereto. The microbridge deck 20 can be a rectangular quadrilateral, and the four supports 30 can be located at the four corners of the rectangular microbridge deck 20. The electrostatic force applying mechanism can include four electrostatic force applying sub-mechanisms, each corresponding to one of the four supports 30.

[0042] Each electrostatic force applying sub-mechanism may include a first electrode 11 disposed on the surface of the substrate 10 and surrounding a corresponding support 30, and a second electrode 22 disposed on the microbridge deck 20 and connected to a corresponding support 30. The first electrode 11 and the second electrode 22 correspond to each other vertically, forming a capacitive structure that can apply an electrostatic force to the support 30.

[0043] A dielectric layer 21 may be provided on the microbridge deck 20, and a micromirror surface 23 and a second electrode 22 may be provided on the dielectric layer 21. The micromirror surface 23 is electrically isolated from the second electrode 22 and supported on the dielectric layer 21. The second electrode 22 may be connected to the upper end of the corresponding support body 30 below through an opening 211 provided in the dielectric layer 21.

[0044] The first electrode 11 can be connected to a control circuit provided in the substrate 10, and the second electrode 22 can be connected to the control circuit through a conductive support 30. The control circuit is used to apply an electrostatic force to at least one of the supports 30 through the first electrode 11 and the second electrode 22 provided in each electrostatic force applying sub-mechanism.

[0045] In some embodiments, the lower end of the support body 30 can be connected to the control circuit through the landing metal structure 12 provided on the surface of the substrate 10. The first electrode 11 can be provided around the landing metal structure 12 and electrically isolated from the landing metal structure 12. Figure 3 shown.

[0046] In some embodiments, the support body 30 can be connected to the middle portion of the bottom surface of the second electrode 22 through its upper end. Thus, the upper end of each support body 30 is connected to a second electrode 22 disposed on the microbridge deck 20, and the lower end of each support body 30 is correspondingly connected to a landing metal structure 12 disposed on the surface of the substrate 10. Each landing metal structure 12 is surrounded by a ring-shaped first electrode 11 disposed on the surface of the substrate 10 and corresponding to a second electrode 22 above it. The micromirror surface 23 is located on the microbridge deck 20 outside each second electrode 22, that is, the micromirror surface 23 is located on the microbridge deck 20 between the four second electrodes 22 and is electrically isolated from each second electrode 22 and the support body 30.

[0047] In some embodiments, the support body 30 may include a spring structure having elasticity along its height direction.

[0048] In some embodiments, the spring structure may include multiple conductive vertical support segments 31 and horizontal support segments 32. The vertical support segments 31 and horizontal support segments 32 are alternately connected end to end, forming an elastic transition structure in the height direction of the support body 30, thereby forming a spring structure. The spring structure may have a vertical support segment 31 at each of its upper and lower ends. The vertical support segment 31 at the lower end of the spring structure is connected to the top surface of the landing metal structure 12 via its lower end, and the vertical support segment 31 at the upper end of the spring structure is connected to a corresponding upper second electrode 22 via its upper end.

[0049] In some embodiments, initially, the control circuit and the electrostatic force applying mechanism (electrostatic force applying sub-mechanism) can be used to energize the first electrode 11 and the second electrode 22 that constitute the capacitor to generate a certain electrostatic force, which acts on the corresponding support body 30, so that each support body 30 remains in a steady state under the combined action of the electrostatic force and its own elastic force.

[0050] When the micromirror needs to be deflected, an electrostatic force different from that applied to the other supports 30 is applied to at least one of the four supports 30, causing the spring structure of that support 30 to elastically expand or compress relative to the height of the other supports 30. This, in turn, causes the microbridge deck 20 and the micromirror surface 23 to deflect in corresponding directions and angles. Furthermore, by applying different combinations of electrostatic forces to the four supports 30, the heights of the four corners of the micromirror can be controlled by electrostatic force, allowing the micromirror surface 23 to follow the microbridge deck 20 and deflect in any desired direction and at a specific angle.

[0051] Furthermore, when adjusting the deflection of the micromirror surface 23, the elastic force of the support body 30 can be utilized to reduce the pull-in voltage required to drive the micromirror deflection, thereby significantly improving the problem of the existing method of using a double-ended fixed torsion arm to support the micromirror, which requires overcoming the rigidity of the torsion arm when driving the micromirror, resulting in a higher pull-in voltage.

[0052] Furthermore, when the desired micromirror deflection angle is large, electrostatic force can be applied to cause the four support bodies 30 to elastically stretch in height, even if the microbridge deck 20 is raised as a whole, thereby increasing the suspended height of the microbridge deck 20 above the substrate 10, thereby forming a sufficient cavity below the microbridge deck 20 to accommodate the large micromirror deflection angle. Conversely, when the desired micromirror deflection angle is small, electrostatic force can be applied to cause the four support bodies 30 to elastically compress in height, even if the microbridge deck 20 is lowered as a whole, thereby reducing the suspended height of the microbridge deck 20 above the substrate 10, thereby meeting the cavity requirement for accommodating the small micromirror deflection angle. Thus, the present invention effectively solves the problem in the prior art of requiring a large cavity structure to be pre-formed below the micromirror to match the rotation angle, which greatly increases the product process complexity.

[0053] A micromirror array of the present invention includes the elastically supported micromirror units described above. The micromirror units are sequentially arranged in rows and columns on the same substrate 10 to form an elastically supported micromirror array.

[0054] In some embodiments, an application-specific integrated circuit (ASIC circuit) may be provided in the substrate 10, and a control circuit may be provided in the application-specific integrated circuit, which is used to apply a force to at least one support body 30 on each micromirror unit through a force-applying mechanism provided on each micromirror unit, causing the support body 30 to elastically stretch or compress in height accordingly, thereby driving the microbridge deck 20 and the micromirror surface 23 of each micromirror unit to independently deflect in corresponding directions and angles.

[0055] In some embodiments, the micromirror array may have an area on the substrate 10 corresponding to that of an application specific integrated circuit.

[0056] The micromirror unit of the present invention has a simple structure, and the required cavity height is limited at the same deflection angle. Therefore, miniaturization can be achieved using technology that is fully compatible with CMOS technology. This not only significantly reduces the process complexity of the product, but also enables the micromirror array composed of micromirror units to be directly implemented on a substrate 10 (such as a silicon wafer) with a dedicated integrated circuit and can share area with the dedicated integrated circuit, thereby significantly improving product performance and reducing costs.

[0057] The following further describes in detail a method for manufacturing an elastically supported micromirror unit of the present invention through specific embodiments and in conjunction with the accompanying drawings.

[0058] See also Figure 4-11 , Figure 4-11 This is a process flow diagram of a method for manufacturing an elastically supported micromirror unit according to a preferred embodiment of the present invention, which shows the local structure of one corner region of the micromirror unit in each step (i.e., the local structure of the micromirror unit in the region where a support body 30 is located). Figure 4-11 As shown, the elastically supported micromirror unit manufacturing method of the present invention can be used to manufacture, for example, Figure 1 ( Figure 2 、 Figure 3 ) as shown in an elastically supported micromirror unit, and may include the following steps:

[0059] Step S1: providing a substrate 10.

[0060] See also Figure 4 A silicon wafer substrate 10 on which an application specific integrated circuit (ASIC circuit) has been fabricated can be used to further fabricate an elastically supported micromirror unit of the present invention on the substrate 10 .

[0061] The manufactured ASIC may include a control circuit for controlling the deflection of the micromirror, which can be understood by referring to the prior art.

[0062] Step S2 : forming a first electrode metal layer on the surface of the substrate 10 and patterning it to form at least three landing metal structures 12 and corresponding first electrodes 11 surrounding each landing metal structure 12 .

[0063] See also Figure 4 First, a deposition process or the like can be used to form a first electrode metal layer on the surface of the substrate 10. The material of the first electrode metal layer can be, for example, aluminum.

[0064] Then, the first electrode metal layer can be patterned using photolithography and etching processes to form, for example, four landing metal structures 12 on the surface of the substrate 10, and corresponding annular first electrodes 11 surrounding each landing metal structure 12. The four landing metal structures 12 can be positioned at the four corners of a defined, for example, rectangular micro-bridge deck 20.

[0065] The gaps between the formed first electrode metal layer patterns may be filled with a dielectric material (not shown).

[0066] Step S3: A sacrificial layer is formed on the surface of the substrate 10 to cover the landing metal structure 12 and the first electrode 11, and a metal support body 30 with a turning structure corresponding to each landing metal structure 12 is formed in the sacrificial layer, so that the lower end of the support body 30 is connected to the top surface of the landing metal structure 12, and the upper end of the support body 30 is exposed from the surface of the sacrificial layer.

[0067] Multiple layers of sacrificial layers can be formed in sequence on the surface of the substrate 10 to cover the landing metal structure 12 and the first electrode 11, and connected metal vertical support segments 31 and metal horizontal support segments 32 corresponding to each landing metal structure 12 are alternately formed in each layer of the sacrificial layer. Among them, the lower end of the vertical support segment 31 located in the lowest sacrificial layer can be connected to the top surface of the landing metal structure 12, the upper end of the vertical support segment 31 located in the uppermost sacrificial layer can be exposed from the surface of the uppermost sacrificial layer, and the two vertical support segments 31 located in the upper and lower layers of any horizontal support segment 32 can be respectively arranged on the upper and lower surfaces of the two opposite ends of the horizontal support segment 32 of this layer, thereby forming a metal support body 30 with a turning structure corresponding to each landing metal structure 12 in the sacrificial layer, which is composed of multiple vertical support segments 31 and multiple horizontal support segments 32 alternately connected, so that the support body 30 is connected to the top surface of the landing metal structure 12 through the lower end of the vertical support segment 31 located in the lowest sacrificial layer, and the support body 30 is exposed from the surface of the sacrificial layer through the upper end of the vertical support segment 31 located in the uppermost sacrificial layer (please refer to Figure 1 to understand).

[0068] In this embodiment, please refer to Figure 4 A deposition process or the like may be used to first form a first sacrificial layer 41 (the lowermost sacrificial layer) on the surface of the substrate 10 and cover the landing metal structure 12 and the first electrode 11 .

[0069] Then, four first grooves 411 corresponding to the four landing metal structures 12 can be formed on the surface of the first sacrificial layer 41 by using photolithography and etching processes, and the bottoms of the first grooves 411 stop on the top surfaces of the corresponding landing metal structures 12.

[0070] See also Figure 5 Next, a conformal deposition process may be used to conformally form the first supporting metal layer 301 on the inner wall surface of the first groove 411 , and the first supporting metal layer 301 material located on the bottom surface of the first groove 411 contacts the top surface of the corresponding landing metal structure 12 .

[0071] Next, a deposition process or the like may be used to fill the first groove 411 in the first supporting metal layer 301 to form a second sacrificial layer 42 that fills the first groove 411 .

[0072] See also Figure 6 Then, planarization may be performed by, for example, a chemical mechanical polishing process to remove excess first support metal layer 301 material and second sacrificial layer 42 material on the surface of the first sacrificial layer 41 outside the first groove 411 .

[0073] See also Figure 7. Next, the first supporting metal layer 301 located in the first groove 411 can be patterned using photolithography and etching processes, etc., to remove portions of the first supporting metal layer 301 and the second sacrificial layer 42 material in the first groove 411 along the longitudinal direction, forming a first layer vertical support segment 311 (the lowest vertical support segment 31) of the first supporting metal layer 301 material on the surface of a portion of the inner wall of the first groove 411 (including a portion of the side wall of the first groove 411 and a portion of the corresponding bottom surface below). Vertical patterns 421 of the second sacrificial layer material are also formed on the side surfaces of the first layer vertical support segment 311. The lower ends of the formed first layer vertical support segments 311 are connected to the top surfaces of the corresponding landing metal structures 12. Through patterning, L-shaped sheet-like or strip-like first layer vertical support segments 311 can be formed on the surface of a portion of the inner wall of the first groove 411 to reduce the rigidity of the first supporting metal layer 301 material and bring out its elasticity. In which, the L-shaped vertical part of the first layer vertical support segment 311 is located on the side wall of the first groove 411, the L-shaped horizontal part of the first layer vertical support segment 311 is located on the bottom surface of the first groove 411, and the vertical pattern 421 of the second sacrificial layer material is located on the surface of the protruding part of the L-shaped horizontal part of the first layer vertical support segment 311.

[0074] See also Figure 8 Next, a deposition process or the like can be used to fill the remaining space of the first recess 411 outside the first vertical support segment 311 (including the vertical pattern 421 of the second sacrificial layer material) to form a third sacrificial layer 43 that fills the first recess 411. Furthermore, by planarization, the excess third sacrificial layer 43 material on the surface of the first sacrificial layer 41 outside the first recess 411 is removed, exposing the upper end of the first vertical support segment 311.

[0075] See also Figure 9 Then, a second supporting metal layer may be formed on the surface of the first sacrificial layer 41 by a deposition process, etc., and cover the top surface of the first groove 411 so that the second supporting metal layer contacts the upper end of the exposed first layer vertical supporting segment 311 .

[0076] Next, the second supporting metal layer can be patterned by using photolithography and etching processes, etc., to form a first-layer horizontal supporting segment 321 of the second supporting metal layer material on the surface of the first sacrificial layer 41, and the formed first-layer horizontal supporting segment 321 is connected to the upper end of the first-layer vertical supporting segment 311 through one end (the right end is shown in the figure).

[0077] See also Figure 10. Then, a deposition process or the like can be used to form a fourth sacrificial layer 44 on the surface of the first sacrificial layer 41 to cover each first-layer vertical support segment 311 and the first-layer horizontal support segment 321. Similar steps as mentioned above can be used to form a second-layer vertical support segment 312 on the side wall of the second groove portion in the fourth sacrificial layer 44, and connect the lower end of the second-layer vertical support segment 312 to the surface of the other end (the left end in the figure) of the first-layer horizontal support segment 321; and form a second-layer horizontal support segment 322 on the surface of the fourth sacrificial layer 44, and connect the formed second-layer horizontal support segment 322 to the upper end of the second-layer vertical support segment 312 through one end (the left end in the figure).

[0078] When forming the second-layer vertical support segment 312, similarly, it may also include simultaneously forming a vertical pattern of the fifth sacrificial layer material on the side of the second-layer vertical support segment 312, and filling the remaining space of the second groove outside the second-layer vertical support segment 312 (including the vertical pattern of the fifth sacrificial layer material) to form a sixth sacrificial layer that fills the second groove.

[0079] See also Figure 11 . Afterwards, a deposition process or the like can be used to form a seventh sacrificial layer 45 (the uppermost sacrificial layer) on the surface of the fourth sacrificial layer 44, covering each second-layer vertical support segment 312 and the second-layer horizontal support segment 322. Similar steps as described above can be used to form a third-layer vertical support segment 313 (the uppermost vertical support segment 31) located on the sidewall of the third groove portion in the seventh sacrificial layer 45, and the lower end of the third-layer vertical support segment 313 is connected to the surface of the other end (the right end in the figure) of the second-layer horizontal support segment 322, so that the upper end of the third-layer vertical support segment 313 is exposed from the surface of the seventh sacrificial layer 45. Thus, an aluminum metal support body 30 with a spring structure having a turning structure is formed, which is composed of three vertical support segments 31 and two horizontal support segments 32 alternately connected. The spring structure with a turning shape formed by alternatingly connecting sheet-like or strip-like vertical support segments 31 and horizontal support segments 32 can have a certain elastic force, which can not only support the micro-bridge deck 20, but also produce a certain amplitude of elastic changes in the up and down height when subjected to electrostatic force, thereby forming a cavity structure with adjustable size under the micro-bridge deck 20.

[0080] When forming the third-layer vertical support segment 313, similarly, a vertical pattern of the eighth sacrificial layer material may be simultaneously formed on the side of the third-layer vertical support segment 313, and a ninth sacrificial layer may be filled in the remaining space of the third groove outside the third-layer vertical support segment 313 (including the vertical pattern of the eighth sacrificial layer material) to fill the third groove.

[0081] According to design requirements and referring to the above steps, a support body 30 having more layers of turning structures can be formed in the sacrificial layer.

[0082] The first to ninth sacrificial layers collectively form a sacrificial layer. The material of each sacrificial layer must be different from the other structural materials of the substrate 10 and the micromirror unit and have a high etching selectivity. For example, the sacrificial layer material can be silicon dioxide or polyimide. The material of each supporting metal layer (the material of each vertical support segment 31 and each horizontal support segment 32) can be, for example, aluminum, thereby forming a resilient aluminum support body 30.

[0083] Step S4 : forming a dielectric layer 21 pattern covering the upper end of the support body 30 on the surface of the sacrificial layer, and forming an opening 211 in the dielectric layer 21 pattern corresponding to the upper end of the support body 30 .

[0084] See also Figure 11 Afterwards, a deposition process or the like can be used to form a dielectric layer 21 on the surface of the seventh sacrificial layer 45, covering the exposed upper ends of the four support bodies 30. Patterning can also be performed to form a rectangular dielectric layer 21 pattern that defines the outline of the microbridge deck 20, and four corresponding through-going openings 211 are formed in the dielectric layer 21 pattern at the upper ends of the four support bodies 30. The dielectric layer 21 material can be, for example, silicon nitride.

[0085] Step S5: A second electrode metal layer is formed on the surface of the sacrificial layer, the dielectric layer 21 is patterned and covered, and a second electrode 22 corresponding to the first electrode 11 and connected to the upper end of the support body 30 through the opening 211 is formed on the pattern surface of the dielectric layer 21, as well as a micromirror surface 23 isolating the micromirror surfaces 23 located between the second electrodes 22, thereby forming a microbridge bridge surface 20.

[0086] See also Figure 11 Then, a deposition process or the like can be used to form a second electrode metal layer on the surface of the seventh sacrificial layer 45, covering the dielectric layer 21 pattern so that the second electrode metal layer material is filled through the opening 211 and contacts the upper end of the underlying support 30. Furthermore, by patterning, four second electrodes 22 corresponding to the first electrodes 11 and connected to the upper end of the support 30 through the opening 211 are formed on the surface of the four corners of the dielectric layer 21 pattern, as well as a micromirror surface 23 (not shown, refer to FIG. 1 ) located between the four second electrodes 22 and separated from the second electrodes 22. Figure 1-Figure 2 ), thereby forming a micro-bridge bridge surface 20 supported on four support bodies 30 and having a micro-mirror surface 23 and four second electrodes 22 arranged on the dielectric layer 21 pattern.

[0087] Step S6 : removing the sacrificial layer to release the microbridge structure formed by the microbridge deck 20 and the support body 30 , thereby forming the microbridge deck 20 and the micromirror surface 23 elastically supported on the substrate 10 by the support body 30 .

[0088] Finally, an etching process (release process) can be used to remove all the above-mentioned sacrificial layers by utilizing the high etching selectivity of the sacrificial layer relative to other structural materials, thereby releasing the microbridge structure formed by the microbridge deck 20 and the four support bodies 30, forming, for example Figure 1 ( Figure 2 、 Figure 3 ) shows a micromirror unit structure in which a micro-bridge surface 20 is elastically supported on a substrate 10 by four supporting bodies 30 and has a micromirror mirror surface 23.

[0089] A micromirror array can be manufactured by forming a plurality of micromirror units arranged in sequence on the same substrate 10 using the aforementioned steps.

[0090] The micromirror unit of the present invention has a simple structure and can be implemented using technology that is fully compatible with CMOS technology, which can significantly reduce the process complexity of the product. It can also enable a micromirror array composed of micromirror units to be directly implemented on a silicon wafer substrate 10 with an ASIC circuit and can share area with the ASIC circuit, thereby significantly improving product performance and reducing costs.

[0091] While the embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations of these embodiments are possible. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as set forth in the claims. Furthermore, the invention described herein is susceptible to other embodiments and may be practiced or implemented in a variety of ways.

Claims

1. An elastically supported micromirror unit, characterized in that: include: A microbridge structure provided on a substrate, wherein the microbridge structure is provided with a microbridge deck, the microbridge deck being elastically supported on the substrate by at least three elastic supports, and a micromirror surface being provided on the microbridge deck, the micromirror surface being isolated from the support body; The substrate is provided with a force-applying mechanism, which applies a force to at least one of the supporting bodies, causing the supporting bodies to elastically stretch or compress in height, thereby causing the micro-bridge surface and the micro-mirror surface to deflect in corresponding directions and angles. The force applying mechanism includes an electrostatic force applying mechanism for applying an electrostatic force to at least one of the supports; the electrostatic force applying mechanism includes a first electrode provided on the surface of the substrate and surrounding the support, and a second electrode provided on the bridge surface of the micro-bridge and connected to the support, the first electrode and the second electrode form a capacitor structure for applying an electrostatic force to the support, and the micro-mirror surface is electrically isolated from the second electrode; the first electrode is connected to a control circuit provided in the substrate, and the second electrode is connected to the control circuit through the conductive support, and the control circuit is used to pass the first electrode and the The second electrode applies an electrostatic force to at least one of the support bodies; the lower end of the support body is connected to the control circuit through a landing metal structure provided on the surface of the substrate, the first electrode is arranged around the landing metal structure and is electrically isolated from the landing metal structure, and the support body is connected to the middle part of the bottom surface of the second electrode through the upper end; the support body includes a spring structure with elasticity along its height direction; the spring structure includes a plurality of conductive vertical support segments and horizontal support segments, the vertical support segments and the horizontal support segments are alternately connected to form an elastic turning structure in the height direction of the support body.

2. The elastically supported micromirror unit according to claim 1, wherein: The microbridge deck includes a quadrilateral, and the four supporting bodies are respectively arranged on the four corners of the quadrilateral of the microbridge deck. The upper end of each supporting body is connected to a second electrode arranged on the microbridge deck, and the lower end of each supporting body is correspondingly connected to a landing metal structure arranged on the substrate surface. Each landing metal structure is surrounded by a ring-shaped first electrode located on the substrate surface and corresponding to the second electrode above. The micromirror surface is located on the microbridge deck outside each second electrode, and is electrically isolated from each second electrode and the supporting body.

3. A micromirror array, characterized in that: The elastically supported micromirror unit comprises the elastically supported micromirror unit according to any one of claims 1 to 2, wherein the micromirror units are arranged in sequence in rows and columns on the same substrate to form an elastically supported micromirror array.

4. The micromirror array according to claim 3, wherein A dedicated integrated circuit is provided in the substrate, and a control circuit is provided in the dedicated integrated circuit, which is used to apply a force to at least one support body on each micromirror unit through a force-applying mechanism provided on each micromirror unit, causing the support body to elastically stretch or compress in height accordingly, thereby causing the microbridge surface and the micromirror surface of each micromirror unit to independently deflect in corresponding directions and angles. The micromirror array has an occupied area on the substrate corresponding to the dedicated integrated circuit.

5. A method for manufacturing an elastically supported micromirror unit, characterized in that: include: providing a substrate; forming a first electrode metal layer on the surface of the substrate and patterning the layer to form at least three landing metal structures and a first electrode surrounding each of the landing metal structures; forming a sacrificial layer on the surface of the substrate to cover the landing metal structure and the first electrode; forming a metal support body having a turning structure corresponding to each of the landing metal structures in the sacrificial layer, such that the lower end of the support body is connected to the top surface of the landing metal structure and the upper end of the support body is exposed from the surface of the sacrificial layer; forming a dielectric layer pattern covering the upper end of the support body on the surface of the sacrificial layer, and forming an opening on the dielectric layer pattern corresponding to the upper end of the support body; forming a second electrode metal layer on the surface of the sacrificial layer, covering the dielectric layer pattern and patterning the second electrode corresponding to the first electrode and connected to the upper end of the support body through the opening on the dielectric layer pattern surface, and isolating the micromirror surfaces between the second electrodes, thereby forming a microbridge bridge surface; The sacrificial layer is removed to release the microbridge structure formed by the microbridge bridge surface and the support body, thereby forming the microbridge bridge surface and the micromirror surface elastically supported on the substrate by the support body.

6. The method for manufacturing an elastically supported micromirror unit according to claim 5, wherein: The step of forming a sacrificial layer on the surface of the substrate to cover the landing metal structure and the first electrode, and forming a metal support having a turning structure corresponding to each landing metal structure in the sacrificial layer, such that the lower end of the support is connected to the top surface of the landing metal structure and the upper end of the support is exposed from the surface of the sacrificial layer, specifically includes: forming multiple sacrificial layers in sequence on the surface of the substrate to cover the landing metal structure and the first electrode; Alternately forming connected metal vertical support segments and metal horizontal support segments corresponding to each of the landing metal structures in the sacrificial layers of each layer; Among them, the lower end of the vertical support segment located in the lowest sacrificial layer is connected to the top surface of the landing metal structure, the upper end of the vertical support segment located in the highest sacrificial layer is exposed from the surface of the highest sacrificial layer, and the two vertical support segments located in the upper and lower layers of any one layer of horizontal support segments are respectively arranged on the upper and lower surfaces of the two opposite ends of the horizontal support segments of that layer, thereby forming a metal support body with a turning structure corresponding to each landing metal structure in the sacrificial layer, which is composed of multiple vertical support segments and multiple horizontal support segments alternately connected, so that the support body is connected to the top surface of the landing metal structure through the lower end of the vertical support segment located in the lowest sacrificial layer, and the support body is exposed from the surface of the sacrificial layer through the upper end of the vertical support segment located in the highest sacrificial layer.

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