A micromirror structure with low pull-in voltage and a manufacturing method thereof

Abstract

The present invention discloses a micromirror structure with a low pull-in voltage and a manufacturing method. The micromirror structure comprises: an anchor point provided on a substrate; a micromirror surface suspended from the substrate via one end connected to the anchor point; and addressing electrodes provided on the substrate below the micromirror surface. The micromirror surfaces correspond to the anchor points in a one-to-one relationship. Under electrostatic drive from the addressing electrodes, the micromirror surface tilts relative to the substrate surface. Upon loss of electrostatic drive from the addressing electrodes, the micromirror surface elastically returns to its original position. The present invention effectively reduces the pull-in voltage of the micromirror, is compatible with CMOS process designs, and has the advantages of a relatively simple structure and low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of micro-electromechanical systems (MEMS), and in particular to a micro-mirror structure with low pull-in voltage and a manufacturing method thereof. Background Art

[0002] Currently, projection display technology has increasingly higher requirements for resolution. Most of the micromirrors used in this technology have relatively complex structures and are relatively large in size (usually ranging from 7 to 20 μm, and rarely less than 5 μm).

[0003] Since the chip size with a large-scale micromirror array is relatively large, the chip cost increases, as well as the cost of packaging and projection optical systems increases.

[0004] Moreover, large-sized micromirror array chips are not suitable for applications with high size and weight requirements. For example, wearable display devices require micromirror array chips with small size and weight. Applications such as AR glasses also require micromirror array chips with high resolution and small size. These applications require the miniaturization of micromirrors.

[0005] At the same time, existing micromirrors usually use a torsion arm with double-ended fixed support to support the micromirror surface, and a commonly used driving mode is the electrostatic drive mode, which drives the micromirror to rotate around the torsion arm to achieve control of the micromirror deflection angle. Since the two ends of the torsion arm are fixedly supported on the anchor point, when the electrostatic drive is used to drive the micromirror surface to deflect, it is necessary to overcome the rigidity of the torsion arm structure, which results in a higher pull-in voltage required for driving the micromirror, and generally exceeds the operating voltage of conventional CMOS circuits (e.g., 5V, 3.3V, 1.8V, etc.). Therefore, when the micromirror array chip is working, a high-voltage chip is generally required to cooperate, and a higher bias voltage is applied to the micromirror so that the micromirror is in a bistable state. Then, a voltage compatible with the CMOS operating voltage is applied to the addressing electrode to deflect the micromirror. This leads to increased complexity and cost of the system.

[0006] In addition, as the size of the micromirror decreases, the area of the electrostatic actuator also decreases, making it difficult to reduce the pull-in voltage proportionally. Summary of the Invention

[0007] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and provide a micromirror structure with low pull-in voltage and a manufacturing method thereof.

[0008] To achieve the above object, the technical solution of the present invention is as follows:

[0009] The present invention provides a micromirror structure with a low pull-in voltage, comprising:

[0010] An anchor point provided on a substrate, a micromirror surface connected to the anchor point via one end and suspended on the substrate, and an addressing electrode provided on the substrate below the micromirror surface;

[0011] Wherein, the mirror surfaces of the micromirrors are arranged in one-to-one correspondence with the anchor points;

[0012] The micromirror surface is integrally tilted relative to the substrate surface under the electrostatic drive from the addressing electrode, and is integrally restored under the elastic effect when the electrostatic drive from the addressing electrode is lost.

[0013] Furthermore, the shape of the micromirror surface includes a polygon, the anchor point includes an elastic sheet-like support column provided on the surface of the substrate, the micromirror surface is elastic, and is directly connected to the anchor point with one corner end of the polygon as a connection fulcrum.

[0014] Furthermore, the micromirror surface is connected to the first end of the elastic cantilever beam through one end, the second end of the cantilever beam is connected to the anchor point, and the micromirror surface is symmetrically distributed on both sides of the line connecting the first end and the second end of the cantilever beam; wherein the micromirror surface is arranged in a one-to-one correspondence with the cantilever beam and the anchor point.

[0015] Furthermore, the micromirror surface and the cantilever beam are located at the same level; wherein, the first end of the cantilever beam is directly connected to one end of the micromirror surface, and the second end of the cantilever beam is directly connected to the top of the anchor point.

[0016] Furthermore, the micromirror surface and the cantilever beam are located at different levels; wherein, the second end of the cantilever beam is directly connected to the top of the anchor point, and one end of the micromirror surface is connected to the first end of the cantilever beam through a connecting column and is suspended between the substrate and the cantilever beam.

[0017] Furthermore, the micromirror surface and the cantilever beam are located at different levels; wherein, the second end of the cantilever beam is directly connected to the top of the anchor point, and one end of the micromirror surface is connected to the first end of the cantilever beam through a connecting column and is lifted above the cantilever beam.

[0018] Furthermore, the cantilever beam includes a straight cantilever beam or a reciprocatingly bent broken-line cantilever beam.

[0019] Furthermore, the shape of the micromirror surface includes a first quadrilateral, and a corner portion of the first quadrilateral at a corner end aligned with the anchor point is symmetrically cut inward along the diagonal line to form a second quadrilateral notch smaller than the first quadrilateral, the cantilever beam is located in the notch, and the first end and the second end of the cantilever beam are connected between the micromirror surface and the anchor point along the diagonal line.

[0020] Furthermore, the shape of the micromirror surface includes a first quadrilateral, and a corner portion of the first quadrilateral at a second corner end aligned with the anchor point is symmetrically cut inward along a diagonal line to form a second quadrilateral notch smaller than the first quadrilateral, and the first end and the second end of the cantilever beam are connected along the diagonal line between the first corner end of the first quadrilateral of the micromirror surface and the anchor point.

[0021] Furthermore, the shape of the micromirror surface includes a quadrilateral, the first end and the second end of the cantilever beam are connected between the first corner end of the quadrilateral of the micromirror surface and the anchor point along the diagonal of the quadrilateral, and the second corner end of the quadrilateral relative to the first corner end is aligned up and down with the anchor point.

[0022] The present invention also provides a method for manufacturing a micromirror structure with a low pull-in voltage, comprising:

[0023] providing a substrate;

[0024] forming address electrodes on the surface of the substrate;

[0025] forming a sacrificial layer on the surface of the substrate to cover the addressing electrodes;

[0026] forming a groove downward on the surface of the sacrificial layer on one side of the address electrode;

[0027] forming a continuous metal layer on the surface of the sacrificial layer and on the sidewalls of the trench;

[0028] The metal layer is patterned, and a polygonal micromirror surface corresponding to the position of the addressing electrode is formed on the surface of the sacrificial layer, and a sheet-shaped support column connected to the substrate and serving as an anchor point is formed on the sidewall of the groove, with one corner end of the polygon of the micromirror surface being connected to the top of the support column as a fulcrum, forming a one-to-one correspondence between the anchor point and the micromirror surface;

[0029] The sacrificial layer is removed to release the anchor point and the micromirror surface.

[0030] The present invention also provides a method for manufacturing a micromirror structure with a low pull-in voltage, comprising:

[0031] providing a substrate;

[0032] forming address electrodes on the surface of the substrate;

[0033] forming a sacrificial layer on the surface of the substrate to cover the addressing electrodes;

[0034] forming a through hole downwardly on the surface of the sacrificial layer on one side of the address electrode;

[0035] forming a metal layer on the surface of the sacrificial layer and filling the through hole;

[0036] The metal layer is patterned, and a micromirror surface corresponding to the position of the addressing electrode is formed on the surface of the sacrificial layer, an anchor point connected to the substrate is formed in the through hole, and a cantilever beam is connected between the micromirror surface and the anchor point. The patterning is performed so that the micromirror surface is shaped like a first quadrilateral, and a corner portion of the first quadrilateral at which a corner end is aligned with the anchor point is symmetrically cut inward along a diagonal line to form a second quadrilateral notch smaller than the first quadrilateral, so that the cantilever beam is located in the notch, and the first and second ends of the cantilever beam are connected between the micromirror surface and the anchor point along the diagonal line. The micromirror surface is symmetrically distributed on both sides of the line connecting the first and second ends of the cantilever beam, forming a one-to-one correspondence between the micromirror surface, the cantilever beam, and the anchor point.

[0037] The sacrificial layer is removed to release the micromirror surface and the cantilever beam.

[0038] The present invention also provides a method for manufacturing a micromirror structure with a low pull-in voltage, comprising:

[0039] providing a substrate;

[0040] forming address electrodes on the surface of the substrate;

[0041] forming a first sacrificial layer on the surface of the substrate to cover the addressing electrodes;

[0042] forming a first through hole downwardly on the surface of the first sacrificial layer at one side of the address electrode;

[0043] forming a first metal layer on the surface of the first sacrificial layer and filling the first through hole;

[0044] The first metal layer is subjected to a first patterning process, and a micromirror surface corresponding to the position of the addressing electrode is formed on the surface of the first sacrificial layer, and a first anchor point connected to the substrate is formed in the first through hole. The first patterning process forms a shape of the micromirror surface into a first quadrilateral, and a corner portion of the first quadrilateral at a second corner end aligned with the first anchor point is symmetrically cut inward along a diagonal line to form a second quadrilateral notch smaller than the first quadrilateral. The micromirror surfaces are symmetrically distributed on both sides of the diagonal line.

[0045] forming a second sacrificial layer on the surface of the first sacrificial layer to cover the micromirror surface and the first anchor point;

[0046] forming a second through hole and a third through hole downwardly on the surface of the second sacrificial layer, such that the bottom of the second through hole stops on the top of the first anchor point, and the bottom of the third through hole stops on the surface of the micromirror surface and is aligned with the first corner end of the first quadrilateral opposite to the second corner end;

[0047] forming a second metal layer on the surface of the second sacrificial layer and filling the second through hole and the third through hole;

[0048] Performing a second patterning on the second metal layer, forming a second anchor point connected to the first anchor point in the second through hole, forming a connecting column connected to the micromirror surface in the third through hole, and forming a cantilever beam on the surface of the second sacrificial layer, with both ends connected to the micromirror surface and the second anchor point, forming a one-to-one correspondence between the cantilever beam, the micromirror surface, the first anchor point, and the second anchor point;

[0049] The second sacrificial layer and the first sacrificial layer are removed to release the micromirror surface and the cantilever beam.

[0050] The present invention also provides a method for manufacturing a micromirror structure with a low pull-in voltage, comprising:

[0051] providing a substrate;

[0052] forming address electrodes on the surface of the substrate;

[0053] forming a first sacrificial layer on the surface of the substrate to cover the addressing electrodes;

[0054] forming a first through hole downwardly on the surface of the first sacrificial layer at one side of the address electrode;

[0055] forming a first metal layer on the surface of the first sacrificial layer and filling the first through hole;

[0056] Performing a first patterning on the first metal layer, forming an anchor point connected to the substrate in the first through hole, and forming a cantilever beam connected to the anchor point through a second end on the surface of the first sacrificial layer;

[0057] forming a second sacrificial layer on the surface of the first sacrificial layer to cover the cantilever beam and the anchor point;

[0058] forming a second through hole downwardly on the surface of the second sacrificial layer, so that the bottom of the second through hole stops on the first end surface of the cantilever beam opposite to the second end;

[0059] forming a second metal layer on the surface of the second sacrificial layer and filling the second through hole;

[0060] The second metal layer is subjected to a second patterning process, and a connecting post connected to the first end of the cantilever beam is formed in the second through hole, and a micromirror surface connected to the connecting post is formed on the surface of the second sacrificial layer; wherein, through the second patterning process, the micromirror surface is formed into a quadrilateral, and a first corner end of the micromirror surface located on the same diagonal line of the quadrilateral is connected to the connecting post, a second corner end is vertically aligned with the anchor point, and the micromirror surface is symmetrically distributed on both sides of the diagonal line, forming a one-to-one correspondence between the micromirror surface, the cantilever beam, and the anchor point;

[0061] The second sacrificial layer and the first sacrificial layer are removed to release the micromirror surface and the cantilever beam.

[0062] As can be seen from the above technical solution, the present invention arranges the micromirror surface and the anchor point in a one-to-one correspondence, and adopts a single-ended connection method in which one end is directly connected to the anchor point, or one end of the cantilever beam is indirectly connected to the anchor point, so that the micromirror surface is fixedly supported at one end and suspended on the substrate. Therefore, under the drive of the small electrostatic force (pull-in voltage) of the addressing electrode (electrostatic driver), the micromirror surface can tilt (deflect) as a whole by utilizing the elastic action of itself or the cantilever beam, and can recover as a whole due to the elastic action when the electrostatic drive is lost, thereby significantly improving the problem of high pull-in voltage required to drive the micromirror caused by the existing method of using a torsion arm with double-end fixed support to support the micromirror, and can effectively reduce the pull-in voltage of the micromirror. Moreover, by forming an anchor point in the form of a sheet support column directly connected to the micromirror surface, the elasticity of the support column can be used to make the micromirror surface more easily tilted as a whole under the drive of a smaller electrostatic force; by forming a connected straight cantilever beam or a reciprocatingly bent linear cantilever beam between the micromirror surface and the anchor point, the length of the cantilever beam can be extended as much as possible to appropriately reduce the elasticity of the cantilever beam, thereby further reducing the pull-in voltage of the micromirror; in addition, the micromirror surface can be suspended at a single end below the cantilever beam or lifted above the cantilever beam to adjust the overall structural stiffness of the micromirror, further reduce the pull-in voltage of the micromirror, and enable the micromirror surface to obtain an intact area when being lifted, thereby maximizing the fill factor. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1-Figure 4 Schematic diagram of a micromirror structure with low pull-in voltage according to preferred embodiments 1 to 4 of the present invention;

[0064] Figure 5 A corresponding embodiment of the present invention Figure 1 Schematic diagram of the micromirror structure in an upward direction;

[0065] Figure 6-Figure 7 A corresponding embodiment of the present invention Figure 2 Schematic diagram of the micromirror structure in an upward direction;

[0066] Figure 8-Figure 9 A corresponding embodiment of the present invention Figure 3 Schematic diagram of the top view of the micromirror structure;

[0067] Figure 10-11 A corresponding embodiment of the present invention Figure 4 Schematic diagram of the micromirror structure in an upward direction;

[0068] Figure 12-17 Schematic diagram of the process steps of a method for manufacturing a micromirror structure with a low pull-in voltage according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0069] 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.

[0070] The present invention provides a micromirror structure with a low pull-in voltage, comprising: an anchor point provided on a substrate, a micromirror surface connected to the anchor point via one end and suspended on the substrate, and an addressing electrode provided on the substrate below the micromirror surface; wherein the micromirror surface and the anchor point are provided in a one-to-one correspondence; the micromirror surface tilts as a whole relative to the substrate surface under electrostatic drive from the addressing electrode, and recovers as a whole under the action of elasticity when the electrostatic drive from the addressing electrode is lost.

[0071] The present invention arranges the micromirror surface and the anchor point in a one-to-one correspondence, and adopts a single-ended connection method, where one end of the micromirror surface is directly connected to the anchor point, or one end of a cantilever beam is indirectly connected to the anchor point. This allows the micromirror surface to be fixedly supported at one end and suspended on a substrate. Consequently, the micromirror surface can tilt (deflect) as a whole under the drive of a small electrostatic force (pull-in voltage) from an addressing electrode (electrostatic driver) by utilizing the elastic action of the micromirror surface itself or the cantilever beam. Furthermore, when the electrostatic drive is lost, the micromirror surface can recover as a whole due to the elastic action. This significantly improves the problem of high pull-in voltage required to drive the micromirror caused by the existing method of using a torsion arm with double-ended fixed support, and effectively reduces the pull-in voltage of the micromirror.

[0072] Furthermore, by forming an anchor point in the form of a sheet (or strip) support column directly connected to the micromirror surface, the elasticity of the support column can be used to make the micromirror surface more easily tilted as a whole under the drive of a smaller electrostatic force.

[0073] Furthermore, by forming a connected straight cantilever beam or a reciprocatingly bent broken-line cantilever beam between the micromirror surface and the anchor point, the length of the cantilever beam can be extended as much as possible to appropriately reduce the elasticity of the cantilever beam, thereby further reducing the pull-in voltage of the micromirror.

[0074] Furthermore, the micromirror surface can be suspended at one end below the cantilever beam or lifted above the cantilever beam to adjust the overall structural stiffness of the micromirror, further reduce the pull-in voltage of the micromirror, and enable the micromirror surface to obtain an undamaged area when being lifted, thereby maximizing the fill factor.

[0075] The present invention also provides a method for manufacturing the above-mentioned micromirror structure with low pull-in voltage. The micromirror structure can be designed according to CMOS process design rules and can be manufactured using standard CMOS process. Therefore, the manufacturing process of the micromirror structure can be simplified, and a micromirror with a relatively simple structure can be manufactured, thereby effectively meeting the demand for reducing the pull-in voltage of the micromirror while promoting the continuous miniaturization of the micromirror.

[0076] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0077] See also Figure 1 , Figure 1 This is a schematic diagram of a micromirror structure with a low pull-in voltage according to a preferred embodiment of the present invention (a schematic diagram of a cross-sectional structure, the same below). Figure 1 As shown, a low pull-in voltage micromirror structure of the present invention may include an elastic sheet-shaped (or strip-shaped) support column 120 vertically disposed on a substrate 10 as an anchor point 12, a polygonal micromirror surface 13 directly connected to the top of the support column 120 with one end serving as a fulcrum, and an addressing electrode 14 disposed on one side of the support column 120 and correspondingly located on the surface of the substrate 10 below the micromirror surface 13. This allows for the formation of a compact, small-sized micromirror with a one-to-one correspondence between the micromirror surface 13 and the anchor point 12.

[0078] The micromirror surface 13 is connected to the support column 120 via a single end, thereby obtaining support from the support column 120 and being suspended above the substrate 10 .

[0079] The micromirror surface 13 can generally be made of metal material. For example, the micromirror surface 13 can be an aluminum micromirror surface 13 , and thus has a certain degree of elasticity.

[0080] The support pillars 120 can be made of the same or different metal material as the micromirror surface 13. The sheet-like (or strip-like) support pillar 120 structure can be formed using the sidewalls of a groove in a sacrificial layer (see the following description of the manufacturing method for details) to reduce the rigidity of the anchor point and provide a certain degree of elasticity for the support pillars 120. A dielectric support layer can be provided on the side surfaces of the support pillars 120.

[0081] In some embodiments, the support pillars 120 can be connected to the substrate 10 via the connection electrodes 11 provided on the surface of the substrate 10, thereby enabling the micromirror surface 13 to be connected to an electrostatic driver provided in the substrate 10 via the support pillars 120 and the connection electrodes 11. The addressing electrodes 14 are also connected to the electrostatic driver, thereby forming a pair of parallel plate capacitor electrodes with the micromirror surface 13. In this way, through the power-on control of the electrostatic driver, the micromirror surface 13 can be electrostatically driven by the addressing electrodes 14, and the micromirror surface 13 is attracted downward by the electrostatic force, causing the micromirror surface 13 to tilt relative to the surface of the substrate 10. When the electrostatic drive from the addressing electrodes 14 is lost, the micromirror surface 13 recovers as a whole due to the elasticity of the micromirror surface 13 and the support pillars 120.

[0082] A landing electrode 15 may also be provided on the surface of the substrate 10, away from the addressing electrode 14 on the side of the support pillar 120 (the right side in the figure). The landing electrode 15 is generally maintained at the same potential as the micromirror surface 13. After the micromirror surface 13 is attracted and tilted downward, it can stop on the landing electrode 15 to avoid direct contact with the surface of the substrate 10.

[0083] The addressing electrodes 14 , the landing electrodes 15 and the connecting electrodes 11 may be made of the same or different metal materials as the micromirror surface 13 .

[0084] See also Figure 5 , which displays the corresponding Figure 1 The bottom-up view of the micromirror structure is omitted. In some embodiments, the micromirror surface 13 can be in the shape of a square as shown, and can be directly connected to the top of the support column 120 using one corner of the square (shown as the left corner (the square vertex, the second corner)) as a connection point.

[0085] The landing electrode 15 may be disposed at a position corresponding to another opposite corner end (a right corner end, the first corner end in the figure) of the square micromirror surface 13 .

[0086] The addressing electrode 14 may have a shape adapted to the micromirror surface 13 . For example, the addressing electrode 14 may have a square shape corresponding to the micromirror surface 13 and may have a gap to avoid the connection electrode 11 (support column 120 ) and the landing electrode 15 .

[0087] In this embodiment, the micromirror surface 13 of the present invention is supported by a single-end fixed support with an anchor point 12 , which is in stark contrast to the existing structure of supporting the micromirror with a torsion arm that is fixed at both ends.

[0088] The micromirror of the present invention can have two states: one in which the micromirror surface 13 remains horizontal (or nearly horizontal) when not subjected to electrostatic forces; and the other in which the micromirror surface 13 tilts when driven by an electrostatic driver. When the driving voltage exceeds the micromirror's pull-in voltage, the micromirror will tilt significantly. After the driving voltage is removed, the micromirror surface 13 returns to a horizontal state due to the elastic forces of the micromirror surface 13 itself and the support pillars 120. This effectively reduces the micromirror's pull-in voltage within a small space.

[0089] The present invention provides a method for manufacturing a micromirror structure with a low pull-in voltage, which can be used to manufacture, for example, Figure 1 ( Figure 5 ) as shown above, and may include the following steps:

[0090] See also Figure 1 ( Figure 5 First, a conventional semiconductor substrate 10, such as a silicon substrate 10, may be used, and circuit structures such as CMOS front-end devices including electrostatic actuators required for forming MEMS may be fabricated on the substrate 10.

[0091] Then, a first metal layer can be formed on the surface of the substrate 10 by, for example, a deposition process, and patterned by photolithography and etching processes to form the connection electrodes 11, address electrodes 14, and landing electrodes 15. The first metal layer can be made of, for example, aluminum.

[0092] Next, a sacrificial layer may be deposited on the surface of the substrate 10 using, for example, a deposition process, to cover the connection electrodes 11, the address electrodes 14, and the landing electrodes 15. The sacrificial layer may be made of, for example, silicon dioxide or polyimide.

[0093] Next, a photolithography and etching process is used to form a groove on the surface of the sacrificial layer, and the groove stops at the top surface of the connection electrode 11 on the side of the address electrode 14. The groove can be a rectangular groove or a circular groove, etc., and the present invention is not limited thereto.

[0094] Afterwards, a conformal deposition process, for example, can be used to conformally form a second metal layer on the inner wall of the groove, so that the second metal layer is connected to the connecting electrode 11; the second metal layer is also deposited on the surface of the sacrificial layer outside the groove, thereby forming a continuous second metal layer on the surface of the sacrificial layer and on the side wall (inner wall) of the groove.

[0095] Then, the second metal layer can be patterned by using photolithography and etching processes to form polygons (eg, Figure 5A micromirror surface 13 having a square shape (as shown in the figure) is provided, and a sheet-like (or strip-like) support column 120 is formed on the sidewall of the groove (which may include part of the bottom surface of the groove) and connected to the substrate 10 via the connection electrode 11. The support column 120 is connected to the top of the support column 120 at one corner end (the left corner end is shown in the figure) as a fulcrum. Thus, a one-to-one correspondence between the anchor point 12 and the micromirror surface 13 is formed.

[0096] Finally, the sacrificial layer can be removed by an etching process (e.g., a wet etching release process) and utilizing the high etching selectivity of the sacrificial layer material relative to the substrate 10, the first metal layer, the second metal layer and other structural materials, so that the micromirror surface 13 and the anchor point 12 are released, thereby forming, for example Figure 1 ( Figure 5 ) shows a micromirror structure with low pull-in voltage.

[0097] It should be noted that the anchor point 12 (support column 120 ) and the micromirror surface 13 may also be manufactured using independent process steps and different materials (the same applies below).

[0098] See also Figure 2 , Figure 2 FIG. 1 is a schematic diagram of a micromirror structure with a low pull-in voltage according to a second preferred embodiment of the present invention. Figure 2 As shown, a micromirror structure with a low pull-in voltage of the present invention may include an anchor point 12 (conductive support column) vertically arranged on a substrate 10, and a polygonal micromirror surface 13 supported on the top of the anchor point 12 by a single end of an elastic conductive cantilever beam 16.

[0099] Anchor point 12 can be connected to substrate 10 via connection electrode 11 provided on the surface of substrate 10. Addressing electrode 14 and landing electrode 15 can be sequentially provided on the surface of substrate 10 on the side of connection electrode 11 (anchor point 12), with addressing electrode 14 correspondingly located below micromirror surface 13. This allows the formation of a compact, small-sized micromirror with a one-to-one correspondence between micromirror surface 13, cantilever beam 16, and anchor point 12.

[0100] The micro mirror surface 13 can be Figure 1 、 Figure 6 As shown, the endpoint A on the left side of the micromirror surface 13, which has a gap to avoid the anchor point 12, is directly connected to the first end of the cantilever beam 16 (the right end of the cantilever beam 16 is shown in the figure), and the second end of the cantilever beam 16 (the left end of the cantilever beam 16 is shown in the figure) can be directly connected to the top of the anchor point 12. This forms a micromirror structure in which the micromirror surface 13 and the cantilever beam 16 are located at the same level.

[0101] Furthermore, the micromirror surfaces 13 may be symmetrically distributed on both sides of a line connecting the first end and the second end of the cantilever beam 16 .

[0102] The cantilever beam 16 can be made of the same material as or a different material from the micromirror surface 13 .

[0103] See also Figure 6 , which displays the corresponding Figure 2 The upward-view structure of the micromirror structure after omitting the substrate 10. In some embodiments, the cantilever beam 16 may include a linear cantilever beam 16. The shape of the micromirror surface 13 may be the first square (first quadrilateral) shown in the figure, and the corner of the first square where one corner end is aligned with the anchor point 12 (shown as a cut-off corner end (square vertex, second corner end) on the left side) is symmetrically cut inward along the diagonal line B where the corner end is located, forming a second square (second quadrilateral) gap C that is smaller than the first square. The cantilever beam 16 is located in this avoidance gap C, and the first and second ends of the cantilever beam 16 can be connected between the micromirror surface 13 and the anchor point 12 along the diagonal line B.

[0104] In some embodiments, the cantilever beam 16 may also include a reciprocatingly bent broken line cantilever beam 16 (or a reciprocatingly bent curved cantilever beam), such as Figure 7 shown.

[0105] In this embodiment, the micromirror surface 13 is connected to the anchor point 12 at one end by using a cantilever beam 16 to support the micromirror surface 13. The length of the cantilever beam 16 can be extended as much as possible within the space of the tiny second square gap C. A straight cantilever beam 16 or a multi-fold broken line cantilever beam 16 can be used, and the elasticity of the cantilever beam 16 can be appropriately reduced, thereby further reducing the pull-in voltage of the micromirror.

[0106] The present invention provides a method for manufacturing a micromirror structure with a low pull-in voltage, which can be used to manufacture, for example, Figure 2 ( Figure 6-Figure 7 ) as shown above, and may include the following steps:

[0107] See also Figure 2 ( Figure 6-Figure 7 First, a first metal layer may be formed on the surface of the substrate 10 by, for example, a deposition process, and then patterned by processes such as photolithography and etching to form the connection electrodes 11, the address electrodes 14, and the landing electrodes 15.

[0108] Then, a sacrificial layer may be deposited on the surface of the substrate 10 by, for example, a deposition process, to cover the connection electrodes 11 , the address electrodes 14 and the landing electrodes 15 .

[0109] Next, a photolithography and etching process may be used to form a through hole on the surface of the sacrificial layer, and the etching process stops at the top surface of the connecting electrode 11 .

[0110] Next, a second metal layer may be formed on the surface of the sacrificial layer by, for example, a deposition process, and the like, and the through hole may be filled.

[0111] Then, the second metal layer can be patterned using photolithography and etching processes to form a conductive through-hole-shaped anchor point 12 in the through-hole, which is connected to the substrate 10 through the connecting electrode 11. A micromirror surface 13 corresponding to the position of the addressing electrode 14 is formed on the surface of the sacrificial layer, as well as a cantilever beam 16 (which can be a straight cantilever beam 16 or a zigzag cantilever beam 16 that bends back and forth) connected between the micromirror surface 13 and the anchor point 12.

[0112] In this step, through graphics, the shape of the formed micromirror surface 13 can be made into a first square (first quadrilateral), and the corner of the first square at which the corner end is aligned with the anchor point 12 is symmetrically cut inward along the diagonal line B to form a second square (second quadrilateral) gap C smaller than the first square, so that the synchronously formed cantilever beam 16 is located in the avoidance gap, and the two ends of the cantilever beam 16 are connected between the micromirror surface 13 and the anchor point 12 along the diagonal line, and the micromirror surface 13 is symmetrically distributed on both sides of the connection line (including the extension line of the connection line) of the two ends of the cantilever beam 16, forming a one-to-one corresponding micromirror surface 13, cantilever beam 16 and anchor point 12.

[0113] Finally, the sacrificial layer can be removed by an etching process (e.g., a wet etching release process) and utilizing the high etching selectivity of the sacrificial layer material relative to the substrate 10, the first metal layer, the second metal layer and other structural materials, so that the micromirror surface 13, the cantilever beam 16 and the anchor point 12 are released, thereby forming, for example Figure 2 ( Figure 6-Figure 7 ) shows a micromirror structure with low pull-in voltage.

[0114] See also Figure 3 , Figure 3 Schematic diagram of a micromirror structure with low pull-in voltage according to the third preferred embodiment of the present invention. Figure 3 As shown, a micromirror structure with a low pull-in voltage of the present invention may include an anchor point 12 (conductive support column) vertically arranged on a substrate 10, and a polygonal micromirror surface 13 supported (suspended) on the top of the anchor point 12 by a single-end elastic conductive cantilever beam 16.

[0115] Anchor point 12 can be connected to substrate 10 via connection electrode 11 provided on the surface of substrate 10. Addressing electrode 14 and landing electrode 15 can be sequentially provided on the surface of substrate 10 on the side of connection electrode 11 (anchor point 12), with addressing electrode 14 correspondingly located below micromirror surface 13. This allows the formation of a compact, small-sized micromirror with a one-to-one correspondence between micromirror surface 13, cantilever beam 16, and anchor point 12.

[0116] The micromirror surface 13 and the cantilever beam 16 are located at different horizontal levels. The micromirror surface 13 is located between the substrate 10 and the cantilever beam 16, and the cantilever beam 16 is located above the micromirror surface 13. The second end of the cantilever beam 16 is directly connected to the top of the anchor point 12. One end (the first corner end) of the micromirror surface 13 is connected to the first end of the cantilever beam 16 via a connecting column 17, thereby suspending the micromirror surface 13 between the substrate 10 and the cantilever beam 16. Furthermore, the micromirror surface 13 can be symmetrically distributed on both sides of the line connecting the first and second ends of the cantilever beam 16.

[0117] The cantilever beam 16 can be made of the same material as or a different material from the micromirror surface 13 .

[0118] See also Figure 8 , which shows Figure 3 The top view structure of the micromirror structure. In some embodiments, the cantilever beam 16 may include a straight cantilever beam 16. The shape of the micromirror surface 13 may include a first square (first quadrilateral), and the corner of a second corner end (shown as a cut-off corner end (square vertex) on the left side) aligned with the anchor point 12 on the first square is cut off symmetrically inward along the diagonal line where the second corner end is located, forming a second square (second quadrilateral) gap smaller than the first square (see FIG. Figure 6 The first end and the second end of the cantilever beam 16 may be connected between the first corner end of the first square of the micromirror surface 13 and the anchor point 12 along the diagonal direction.

[0119] In some embodiments, the anchor point 12 can be formed by connecting the first anchor point 121 (first support column) and the second anchor point 122 (second support column), and other connecting material layers (for example, a micromirror surface 13 material layer) can be provided between the first anchor point 121 and the second anchor point 122.

[0120] The first anchor point 121 can be made of the same material as or different from the micromirror surface 13 . The second anchor point 122 and the connecting pillar 17 can be made of the same material as or different from the cantilever beam 16 .

[0121] In some embodiments, the cantilever beam 16 may also include a reciprocatingly bent broken line cantilever beam 16 (or a reciprocatingly bent curved cantilever beam), such as Figure 9 shown.

[0122] In this embodiment, by arranging the cantilever beam 16 and the micromirror surface 13 at different levels, the length of the cantilever beam 16 can be maximized to adjust the overall structural stiffness of the micromirror and reduce the elasticity of the cantilever beam 16, thereby further reducing the pull-in voltage of the micromirror.

[0123] The present invention provides a method for manufacturing a micromirror structure with a low pull-in voltage, which can be used to manufacture, for example, Figure 3 ( Figure 8-Figure 9 ) as shown above, and may include the following steps:

[0124] See also Figure 3 ( Figure 8-Figure 9 First, a third metal layer may be formed on the surface of the substrate 10 by, for example, a deposition process, and a third metal layer may be patterned by photolithography and etching processes to form the connection electrodes 11, the address electrodes 14, and the landing electrodes 15.

[0125] Then, a first sacrificial layer may be deposited on the surface of the substrate 10 by, for example, a deposition process, to cover the connection electrodes 11 , the address electrodes 14 and the landing electrodes 15 .

[0126] Next, a photolithography and etching process may be used to form a first through hole downward on the surface of the first sacrificial layer, and stop at the top surface of the connecting electrode 11 .

[0127] Next, a first metal layer may be formed on the surface of the first sacrificial layer by using, for example, a deposition process, and the like, and the first through hole may be filled.

[0128] Then, the first metal layer can be patterned using a photolithography and etching process to form a micromirror surface 13 corresponding to the position of the addressing electrode 14 on the surface of the first sacrificial layer, and a first anchor point 121 in the form of a conductive through-hole separated from the micromirror surface 13 and connected to the substrate 10 through the connecting electrode 11 is formed in the first through-hole.

[0129] In this step, the first patterning is performed to form the micromirror surface 13 in the shape of a first square (first quadrilateral), and the corner of the first square at a second corner end aligned with the first anchor point 121 is symmetrically cut inward along the diagonal line to form a second square (second quadrilateral) notch smaller than the first square, so that the micromirror surface 13 is symmetrically distributed on both sides of the diagonal line.

[0130] Then, a second sacrificial layer may be formed on the surface of the first sacrificial layer by, for example, a deposition process, to cover the micromirror surface 13 and the first anchor point 121. The material of the second sacrificial layer may be the same as that of the first sacrificial layer.

[0131] Next, a second through hole and a third through hole may be formed downward on the surface of the second sacrificial layer using a photolithography and etching process, so that the bottom of the second through hole stops on the top of the first anchor point 121, and the bottom of the third through hole stops on the surface of the micromirror surface 13 and is aligned with the first corner end position of the first square of the micromirror surface 13 opposite to the second corner end.

[0132] Next, a second metal layer may be formed on the surface of the second sacrificial layer by, for example, a deposition process, and the second through hole and the third through hole are filled.

[0133] Then, a second patterning process can be performed on the second metal layer using photolithography and etching processes. A second anchor point 122 connected to the first anchor point 121 is formed in the second through hole, a connecting column 17 connected to the micromirror surface 13 is formed in the third through hole, and a cantilever beam 16 (which can be a straight cantilever beam 16 or a reciprocatingly bent broken-line cantilever beam) is formed on the surface of the second sacrificial layer, with both ends connected to the micromirror surface 13 and the second anchor point 122. This forms a one-to-one correspondence between the cantilever beam 16, the micromirror surface 13, and the first anchor point 121 and the second anchor point 122 (the connected first anchor point 121 and the second anchor point 122 together form the anchor point 12).

[0134] Finally, the second sacrificial layer and the first sacrificial layer can be removed by an etching process (e.g., a wet etching release process) and utilizing the high etching selectivity of the first sacrificial layer material and the second sacrificial layer material relative to the substrate 10, the first metal layer to the third metal layer and other structural materials, so that the micromirror surface 13, the cantilever beam 16 and the anchor point 12 are released, thereby forming, for example Figure 3 ( Figure 8-Figure 9 ) shows a micromirror structure with low pull-in voltage.

[0135] See also Figure 4 , Figure 4 FIG. 1 is a schematic diagram of a micromirror structure with a low pull-in voltage according to a fourth preferred embodiment of the present invention. Figure 4 As shown, a micromirror structure with a low pull-in voltage of the present invention may include an anchor point 12 (conductive support column) vertically arranged on a substrate 10, and a polygonal micromirror surface 13 supported (lifted) on the top of the anchor point 12 by a single-end elastic conductive cantilever beam 16.

[0136] Anchor point 12 can be connected to substrate 10 via connection electrode 11 provided on the surface of substrate 10. Addressing electrode 14 and landing electrode 15 can be sequentially provided on the surface of substrate 10 on the side of connection electrode 11 (anchor point 12), with addressing electrode 14 correspondingly located below micromirror surface 13. This allows the formation of a compact, small-sized micromirror with a one-to-one correspondence between micromirror surface 13, cantilever beam 16, and anchor point 12.

[0137] The micromirror surface 13 and the cantilever beam 16 are located at different horizontal levels. The cantilever beam 16 is located between the substrate 10 and the micromirror surface 13, and the micromirror surface 13 is located above the cantilever beam 16. The second end of the cantilever beam 16 is directly connected to the top of the anchor point 12. One end (the first corner end) of the micromirror surface 13 is connected to the first end of the cantilever beam 16 via a connecting column 17, thereby supporting the micromirror surface 13 above the cantilever beam 16. Furthermore, the micromirror surface 13 can be symmetrically distributed on both sides of the line connecting the first and second ends of the cantilever beam 16.

[0138] The cantilever beam 16 can be made of the same or different material as the micromirror surface 13. The anchor point 12 can be made of the same or different material as the cantilever beam 16. The connecting post 17 can be made of the same or different material as the micromirror surface 13.

[0139] See also Figure 10 , which displays the corresponding Figure 4 The bottom-view structure of the micromirror structure after omitting the substrate 10 is shown in FIG. In some embodiments, the cantilever beam 16 may include a linear cantilever beam 16. The shape of the micromirror surface 13 may include a square (quadrilateral). The first and second ends of the cantilever beam 16 may be connected along one of the diagonals of the square, between below a first corner of the square micromirror surface 13 and the top of the anchor point 12. The second corner of the square micromirror surface 13, which is opposite to the first corner, is aligned vertically with the anchor point 12.

[0140] In some embodiments, the cantilever beam 16 may also include a reciprocatingly bent broken line cantilever beam 16 (or a reciprocatingly bent curved cantilever beam), such as Figure 11 As shown (the substrate 10, connecting electrode 11, addressing electrode 14 and landing electrode 15 are omitted in the figure).

[0141] In this embodiment, by arranging the cantilever beam 16 and the micromirror surface 13 at different levels, the length of the cantilever beam 16 can also be extended to the maximum extent, so as to adjust the overall structural stiffness of the micromirror and reduce the elasticity of the cantilever beam 16. This can not only further reduce the pull-in voltage of the micromirror, but also enable the micromirror surface 13 to obtain an undamaged area in the lifted state, thereby maximizing the fill factor.

[0142] See also Figure 12-17 , Figure 12-17 FIG. 1 is a schematic diagram of the process steps of a method for manufacturing a micromirror structure with a low pull-in voltage according to a preferred embodiment of the present invention. Figure 12-17 As shown, the present invention provides a method for manufacturing a micromirror structure with a low pull-in voltage, which can be used to manufacture, for example, Figure 4 ( Figure 10-11 ) as shown above, and may include the following steps:

[0143] See also Figure 12 First, a third metal layer may be formed on the surface of the substrate 10 by, for example, a deposition process, and then a third patterning process may be performed by photolithography and etching to form the connection electrodes 11 , the address electrodes 14 and the landing electrodes 15 .

[0144] See also Figure 13 Then, a first sacrificial layer 18 may be deposited on the surface of the substrate 10 by, for example, a deposition process, to cover the connection electrodes 11 , the address electrodes 14 and the landing electrodes 15 .

[0145] Next, a photolithography and etching process may be used to form a first through hole 181 downward on the surface of the first sacrificial layer 18 and stop at the top surface of the connecting electrode 11 .

[0146] See also Figure 14 Next, a first metal layer may be formed on the surface of the first sacrificial layer 18 by, for example, a deposition process, and the like, and the first through hole 181 may be filled.

[0147] Then, the first metal layer can be patterned using a photolithography and etching process to form a conductive through-hole-shaped anchor point 12 in the first through-hole 181 connected to the substrate 10 through the connecting electrode 11, and a cantilever beam 16 connected to the anchor point 12 through the second end is formed on the surface of the first sacrificial layer 18.

[0148] See also Figure 15 Then, a second sacrificial layer 19 may be formed on the surface of the first sacrificial layer 18 by, for example, a deposition process, to cover the cantilever beam 16 and the anchor point 12. The material of the second sacrificial layer 19 may be the same as that of the first sacrificial layer 18.

[0149] Next, a second through hole 191 may be formed downward on the surface of the second sacrificial layer 19 by using photolithography and etching processes, so that the bottom of the second through hole 191 stops at the first end surface of the cantilever beam 16 opposite to the second end.

[0150] See also Figure 16 Next, a second metal layer may be formed on the surface of the second sacrificial layer 19 by, for example, a deposition process, and the like, and the second through hole 191 may be filled.

[0151] Then, the second metal layer can be patterned for the second time using a photolithography and etching process to form a connecting column 17 connected to the first end of the cantilever beam 16 in the second through hole 191, and a micromirror surface 13 connected to the connecting column 17 is formed on the surface of the second sacrificial layer 19.

[0152] In this step, the second patterning process forms a square micromirror surface 13. The first corner of the first and second corners of the micromirror surface 13, located on the same diagonal of the square, is connected to the connecting post 17, the second corner is aligned vertically with the anchor point 12, and the micromirror surface 13 is symmetrically distributed on both sides of the diagonal. This creates a one-to-one correspondence between the micromirror surface 13, the cantilever beam 16, and the anchor point 12.

[0153] See also Figure 17 Finally, the second sacrificial layer 19 and the first sacrificial layer 18 can be removed by an etching process (e.g., a wet etching release process) and utilizing the high etching selectivity of the first sacrificial layer 18 and the second sacrificial layer 19 relative to the substrate 10, the first metal layer to the third metal layer and other structural materials, so as to release the micromirror surface 13, the cantilever beam 16 and the anchor point 12, thereby forming, for example Figure 4 ( Figure 10-11 ) shows a micromirror structure with low pull-in voltage.

[0154] In summary, the low pull-in voltage micromirror structure of the present invention can be designed according to CMOS process design rules and manufactured using standard CMOS processes. This simplifies the manufacturing process of the micromirror structure and allows the production of relatively simple micromirrors. This effectively meets the demand for reducing the pull-in voltage of the micromirrors while promoting the continuous miniaturization of micromirrors. Therefore, the present invention has the potential for widespread application in the field of projection display technology requiring high resolution, small size, and light weight, and has the advantage of relatively low cost.

[0155] 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. A micromirror structure with low pull-in voltage, characterized in that: include: An anchor point provided on a substrate, a micromirror surface connected to the anchor point via one end and suspended on the substrate, and an addressing electrode provided on the substrate below the micromirror surface; Wherein, the mirror surfaces of the micromirrors are arranged in one-to-one correspondence with the anchor points; The micromirror surface is driven by electrostatic force from the addressing electrodes to tilt the entire surface relative to the substrate surface, and recovers the entire surface due to elastic force when the electrostatic force from the addressing electrodes is lost. The micromirror surface has a polygonal shape, and the anchor point includes an elastic sheet-shaped support column provided on the surface of the substrate. The micromirror surface is elastic and is directly connected to the anchor point with one corner end of the polygon as a connection fulcrum. The micromirror surface is connected to the first end of the elastic cantilever beam through one end, the second end of the cantilever beam is connected to the anchor point, and the micromirror surface is symmetrically distributed on both sides of the line connecting the first end and the second end of the cantilever beam; wherein the micromirror surface is arranged in a one-to-one correspondence with the cantilever beam and the anchor point.

2. The micromirror structure with low pull-in voltage according to claim 1, wherein: The micromirror surface and the cantilever beam are located at the same level; wherein, the first end of the cantilever beam is directly connected to one end of the micromirror surface, and the second end of the cantilever beam is directly connected to the top of the anchor point.

3. The micromirror structure with low pull-in voltage according to claim 1, wherein: The micromirror surface and the cantilever beam are located at different levels; wherein, the second end of the cantilever beam is directly connected to the top of the anchor point, and one end of the micromirror surface is connected to the first end of the cantilever beam through a connecting column and is suspended between the substrate and the cantilever beam.

4. The micromirror structure with low pull-in voltage according to claim 1, wherein: The micromirror surface and the cantilever beam are located at different levels; wherein, the second end of the cantilever beam is directly connected to the top of the anchor point, and one end of the micromirror surface is connected to the first end of the cantilever beam through a connecting column and is lifted above the cantilever beam.

5. The micromirror structure with low pull-in voltage according to claim 1, wherein: The cantilever beam includes a straight cantilever beam or a reciprocatingly bent broken-line cantilever beam.

6. The micromirror structure with low pull-in voltage according to claim 2, wherein: The shape of the micromirror surface includes a first quadrilateral, and a corner portion of the first quadrilateral at a corner end aligned with the anchor point is symmetrically cut inward along a diagonal line to form a second quadrilateral notch smaller than the first quadrilateral, the cantilever beam is located in the notch, and the first end and the second end of the cantilever beam are connected between the micromirror surface and the anchor point along the diagonal line.

7. The micromirror structure with low pull-in voltage according to claim 3, wherein: The shape of the micromirror surface includes a first quadrilateral, and a corner portion of the first quadrilateral at a second corner end aligned with the anchor point is symmetrically cut inward along a diagonal line to form a second quadrilateral notch smaller than the first quadrilateral, and the first end and the second end of the cantilever beam are connected along the diagonal line between the first corner end of the first quadrilateral of the micromirror surface and the anchor point.

8. The micromirror structure with low pull-in voltage according to claim 4, wherein: The shape of the micromirror surface includes a quadrilateral, and the first end and the second end of the cantilever beam are connected between the first corner end of the quadrilateral of the micromirror surface and the anchor point along the diagonal line of the quadrilateral, and the second corner end of the quadrilateral relative to the first corner end is aligned up and down with the anchor point.

9. A method for manufacturing a micromirror structure with a low pull-in voltage, for manufacturing the micromirror structure with a low pull-in voltage according to any one of claims 1 to 8, characterized in that: include: providing a substrate; forming address electrodes on the surface of the substrate; forming a sacrificial layer on the surface of the substrate to cover the addressing electrodes; forming a groove downward on the surface of the sacrificial layer on one side of the address electrode; forming a continuous metal layer on the surface of the sacrificial layer and on the sidewalls of the trench; The metal layer is patterned, and a polygonal micromirror surface corresponding to the position of the addressing electrode is formed on the surface of the sacrificial layer, and a sheet-shaped support column connected to the substrate and serving as an anchor point is formed on the sidewall of the groove, with one corner end of the polygon of the micromirror surface being connected to the top of the support column as a fulcrum, forming a one-to-one correspondence between the anchor point and the micromirror surface; The sacrificial layer is removed to release the anchor point and the micromirror surface.

10. A method for manufacturing a micromirror structure with a low pull-in voltage, characterized in that: include: providing a substrate; forming address electrodes on the surface of the substrate; forming a sacrificial layer on the surface of the substrate to cover the addressing electrodes; forming a through hole downwardly on the surface of the sacrificial layer on one side of the address electrode; forming a metal layer on the surface of the sacrificial layer and filling the through hole; The metal layer is patterned, and a micromirror surface corresponding to the position of the addressing electrode is formed on the surface of the sacrificial layer, an anchor point connected to the substrate is formed in the through hole, and a cantilever beam is connected between the micromirror surface and the anchor point. The patterning is performed so that the micromirror surface is shaped like a first quadrilateral, and a corner portion of the first quadrilateral at which a corner end is aligned with the anchor point is symmetrically cut inward along a diagonal line to form a second quadrilateral notch smaller than the first quadrilateral, so that the cantilever beam is located in the notch, and the first and second ends of the cantilever beam are connected between the micromirror surface and the anchor point along the diagonal line. The micromirror surface is symmetrically distributed on both sides of the line connecting the first and second ends of the cantilever beam, forming a one-to-one correspondence between the micromirror surface, the cantilever beam, and the anchor point. The sacrificial layer is removed to release the micromirror surface and the cantilever beam.

11. A method for manufacturing a micromirror structure with a low pull-in voltage, characterized in that: include: providing a substrate; forming address electrodes on the surface of the substrate; forming a first sacrificial layer on the surface of the substrate to cover the addressing electrodes; forming a first through hole downwardly on the surface of the first sacrificial layer at one side of the address electrode; forming a first metal layer on the surface of the first sacrificial layer and filling the first through hole; The first metal layer is subjected to a first patterning process, and a micromirror surface corresponding to the position of the addressing electrode is formed on the surface of the first sacrificial layer, and a first anchor point connected to the substrate is formed in the first through hole. The first patterning process forms a shape of the micromirror surface into a first quadrilateral, and a corner portion of the first quadrilateral at a second corner end aligned with the first anchor point is symmetrically cut inward along a diagonal line to form a second quadrilateral notch smaller than the first quadrilateral. The micromirror surfaces are symmetrically distributed on both sides of the diagonal line. forming a second sacrificial layer on the surface of the first sacrificial layer to cover the micromirror surface and the first anchor point; forming a second through hole and a third through hole downwardly on the surface of the second sacrificial layer, such that the bottom of the second through hole stops on the top of the first anchor point, and the bottom of the third through hole stops on the surface of the micromirror surface and is aligned with the first corner end of the first quadrilateral opposite to the second corner end; forming a second metal layer on the surface of the second sacrificial layer and filling the second through hole and the third through hole; Performing a second patterning on the second metal layer, forming a second anchor point connected to the first anchor point in the second through hole, forming a connecting column connected to the micromirror surface in the third through hole, and forming a cantilever beam on the surface of the second sacrificial layer, with both ends connected to the micromirror surface and the second anchor point, forming a one-to-one correspondence between the cantilever beam, the micromirror surface, the first anchor point, and the second anchor point; The second sacrificial layer and the first sacrificial layer are removed to release the micromirror surface and the cantilever beam.

12. A method for manufacturing a micromirror structure with a low pull-in voltage, characterized in that: include: providing a substrate; forming address electrodes on the surface of the substrate; forming a first sacrificial layer on the surface of the substrate to cover the addressing electrodes; forming a first through hole downwardly on the surface of the first sacrificial layer at one side of the address electrode; forming a first metal layer on the surface of the first sacrificial layer and filling the first through hole; Performing a first patterning on the first metal layer, forming an anchor point connected to the substrate in the first through hole, and forming a cantilever beam connected to the anchor point through a second end on the surface of the first sacrificial layer; forming a second sacrificial layer on the surface of the first sacrificial layer to cover the cantilever beam and the anchor point; forming a second through hole downwardly on the surface of the second sacrificial layer, so that the bottom of the second through hole stops on the first end surface of the cantilever beam opposite to the second end; forming a second metal layer on the surface of the second sacrificial layer and filling the second through hole; The second metal layer is subjected to a second patterning process, and a connecting post connected to the first end of the cantilever beam is formed in the second through hole, and a micromirror surface connected to the connecting post is formed on the surface of the second sacrificial layer; wherein, through the second patterning process, the micromirror surface is formed into a quadrilateral, and a first corner end of the micromirror surface located on the same diagonal line of the quadrilateral is connected to the connecting post, a second corner end is vertically aligned with the anchor point, and the micromirror surface is symmetrically distributed on both sides of the diagonal line, forming a one-to-one correspondence between the micromirror surface, the cantilever beam, and the anchor point; The second sacrificial layer and the first sacrificial layer are removed to release the micromirror surface and the cantilever beam.

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