Preparation method of micro-mechanical switch and micro-mechanical switch

Abstract

The invention provides a preparation method of a micro-mechanical switch and the micro-mechanical switch, and the preparation method of the micro-mechanical switch comprises the steps: providing a first substrate, and preparing a first electrode layer at one side of the first substrate; and providing a second substrate, preparing a first sub-protection layer on one side of the second substrate, and preparing a monocrystalline silicon layer on one side, far away from the second substrate, of the first sub-protection layer. And preparing a second sub-protection layer on one side, away from the substrate, of the monocrystalline silicon layer. And preparing a second electrode layer on one side, far away from the second substrate, of the second sub-protection layer. And etching the first sub-protection layer, the second sub-protection layer and the second substrate to form a switch structure. The orthographic projection of the second driving electrode and the second electrode on the second substrate is located in the orthographic projection of the switch structure layer on the second substrate, one end, far away from the second electrode, of the switch structure is connected with the second substrate, and the other end is suspended. And bonding the side, provided with the second electrode layer, of the second substrate with the side, provided with the first electrode layer, of the first substrate.

Description

Technical Field

[0001] The present application relates to the technical field of micro-electromechanical devices, and in particular to a method for preparing a micro-mechanical switch and a micro-mechanical switch. Background Art

[0002] Micromechanical switches are mechanical switches with sizes ranging from micrometers to millimeters, which are realized by micro-nano manufacturing technology. Micromechanical switches have been widely used in many fields such as radio frequency communication, optical communication, aerospace, etc. due to their small size, low power consumption, fast response speed, high reliability, and easy integration with existing integrated circuits.

[0003] The switch structure obtained by the existing preparation method of micromechanical switch has a short life span and the preparation method is complicated. Summary of the invention

[0004] The present application provides a method for preparing a micromechanical switch and a micromechanical switch.

[0005] A first aspect of the present application provides a method for preparing a micromechanical switch, the method comprising:

[0006] providing a first substrate;

[0007] A first electrode layer is prepared on one side of the first substrate, and the first electrode layer is peeled off to form a first driving electrode and a first pole spaced apart from the first driving electrode;

[0008] providing a second substrate;

[0009] A first sub-protective layer is prepared on one side of the second substrate, and a single crystal silicon layer is prepared on a side of the first sub-protective layer away from the second substrate; the single crystal silicon layer is etched to form a single crystal silicon beam; a second sub-protective layer is prepared on a side of the single crystal silicon layer away from the second substrate, and the orthographic projection of the second sub-protective layer on the second substrate covers the orthographic projection of the single crystal silicon beam on the second substrate;

[0010] A second electrode layer is prepared on a side of the second sub-protection layer away from the second substrate; the second electrode layer is peeled off to form a second driving electrode and a second electrode spaced apart from the second driving electrode;

[0011] The first sub-protective layer, the second sub-protective layer and the second substrate are etched to form a switch structure; the switch structure comprises a single crystal silicon beam and a protective layer consisting of a first sub-protective layer and a second sub-protective layer covering the single crystal silicon beam; the orthographic projections of the second driving electrode and the second pole on the second substrate are located within the orthographic projection of the switch structure on the second substrate; one end of the switch structure away from the second pole is connected to the second substrate, and the other end is suspended;

[0012] The side of the second substrate provided with the second electrode layer is bonded to the side of the first substrate provided with the first electrode layer, so that the orthographic projection of the first driving electrode on the first substrate overlaps with the orthographic projection of the second driving electrode on the first substrate, and the orthographic projection of the first pole on the first substrate overlaps with the orthographic projection of the second pole on the first substrate.

[0013] In one embodiment, after preparing the second electrode layer on the side of the second sub-protection layer away from the second substrate and before etching to form the switch structure, the preparation method further includes:

[0014] A support column is prepared on a side of the second driving electrode away from the second substrate, and the support column is located at an end of the second driving electrode away from the second electrode.

[0015] In one embodiment, before preparing the first electrode layer on one side of the first substrate, the preparation method further includes:

[0016] Etching the first substrate to form a first through hole and a second through hole, wherein the first through hole and the second through hole both connect a surface of the first substrate on which the first electrode layer is to be disposed and another surface opposite to the surface;

[0017] Metal is filled in the first through hole and the second through hole to form a first metal interconnect and a second metal interconnect; the first metal interconnect is used to be electrically connected to the second driving electrode through the support column; the second metal interconnect is used to be electrically connected to the first electrode.

[0018] In one embodiment, before filling the first through hole and the second through hole with metal to form the first metal interconnection and the second metal interconnection, the preparation method further includes:

[0019] A first insulating layer and a second insulating layer are respectively formed on the inner wall of the first through hole and the inner wall of the second through hole.

[0020] In one embodiment, after preparing the second electrode layer on the side of the second sub-protection layer away from the second substrate and before etching to form the switch structure, the preparation method further includes:

[0021] A sealing metal bonding layer is prepared on a side of the second driving electrode away from the second substrate, and an orthographic projection of the sealing metal bonding layer on the second substrate is located outside an orthographic projection of the single crystal silicon beam on the second substrate.

[0022] A second aspect of the present application provides a micromechanical switch, the micromechanical switch is prepared by the above-mentioned preparation method, and the micromechanical switch comprises:

[0023] a first substrate;

[0024] A first electrode layer, located at one side of the first substrate; the first electrode layer comprises a first driving electrode and a first pole spaced apart from the first driving electrode;

[0025] a switch structure, located on a side of the first electrode layer away from the first substrate and spaced apart from the first electrode layer; the switch structure comprises a single crystal silicon beam and a protective layer covering the single crystal silicon beam;

[0026] A second electrode layer is located on a side of the protective layer facing the first electrode layer; the second electrode layer comprises a second driving electrode and a second electrode spaced apart from the second driving electrode;

[0027] The first driving electrode can drive the second driving electrode to drive the single crystal silicon beam to deviate toward the direction close to the first substrate, so that the first electrode contacts the second electrode.

[0028] In one embodiment, the micromechanical switch also includes a second substrate located on a side of the switch structure away from the first substrate; a receiving space for receiving the single crystal silicon beam is provided between the second substrate and the first substrate; the second substrate is connected to the first substrate via a sealing metal bonding layer, and the sealing metal bonding layer is used to seal the receiving space.

[0029] In one embodiment, the first substrate is provided with a first through hole and a second through hole; the first through hole and the second through hole connect the surface of the first substrate facing the switch structure and the surface away from the switch structure; a first metal interconnection is provided in the first through hole; a second metal interconnection is provided in the second through hole; the first metal interconnection is electrically connected to the second driving electrode, and the second metal interconnection is electrically connected to the first electrode.

[0030] In one embodiment, a first insulating layer is disposed between an inner wall of the first through hole and the first metal interconnection; and a second insulating layer is disposed between an inner wall of the second through hole and the second metal interconnection.

[0031] In one embodiment, the material of the second electrode is ruthenium, nickel or cobalt.

[0032] The method for preparing a micromechanical switch provided in an embodiment of the present application uses a single crystal silicon layer to prepare a single crystal silicon beam. The single crystal silicon beam has an extremely high fatigue life, so that the micromechanical switch can be repeatedly opened and closed for a long time without obvious performance degradation or failure, and the elastic modulus of the single crystal silicon beam is small, so that the driving force required for the micromechanical switch is small, thereby reducing the driving voltage and power consumption. In addition, the method for preparing a micromechanical switch of the present application can directly obtain a switch structure by etching the second substrate, which can simplify the process flow of the micromechanical switch and improve production efficiency, and the protective layer can effectively protect the single crystal silicon beam to prevent the single crystal silicon beam from being damaged during etching or other process flows, thereby helping to improve the yield and reliability of the micromechanical switch.

[0033] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0035] Figures 1 to 11 A process flow chart of a method for preparing a micromechanical switch provided in one embodiment of the present application. DETAILED DESCRIPTION

[0036] Here, the technical solutions in the embodiments (or "implementations") of the present application will be described clearly and completely in conjunction with the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0037] If there are terms involving directional indications or positional relationships in the embodiments of the present application (such as up, down, left, right, front, back, inside, outside, top, bottom, center, vertical, horizontal, longitudinal, transverse, length, width, counterclockwise, clockwise, axial, radial, circumferential, etc.), such terms are only used to explain the relative positional relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings); if the specific posture changes, the directional indication or positional relationship will also change accordingly. In addition, the terms "first", "second", etc. involved in the embodiments of the present application are only used for the purpose of convenience of description and cannot be understood as indicating or implying relative importance.

[0038] The following is a detailed description of the method for preparing a micromechanical switch and the micromechanical switch according to the embodiment of the present application in conjunction with the accompanying drawings. In the absence of conflict, the features of the following embodiments and implementations may complement or be combined with each other.

[0039] The present application provides a method for preparing a micromechanical switch. Figures 1 to 11 As shown, the preparation method comprises:

[0040] Step S100: providing a first substrate 10 .

[0041] Step S110 : preparing a first electrode layer 20 on one side of the first substrate 10 , and peeling off the first electrode layer 20 to form a first driving electrode 21 and a first electrode 22 spaced apart from the first driving electrode 21 .

[0042] Step S120: providing a second substrate 30 .

[0043] Step S130: Prepare a first sub-protective layer 31 on one side of the second substrate 30, and prepare a single crystal silicon layer 32 on the side of the first sub-protective layer 31 away from the second substrate 30. Etch the single crystal silicon layer 32 to form a single crystal silicon beam 321. Prepare a second sub-protective layer 33 on the side of the single crystal silicon layer 32 away from the second substrate 30, and the orthographic projection of the second sub-protective layer 33 on the second substrate 30 covers the orthographic projection of the single crystal silicon beam 321 on the second substrate 30.

[0044] Step S140: preparing a second electrode layer 40 on a side of the second sub-protection layer 33 away from the second substrate 30. The second electrode layer 40 is peeled off to form a second driving electrode 41 and a second electrode 42 spaced apart from the second driving electrode 41.

[0045] Step S150: Etching the first sub-protective layer 31, the second sub-protective layer 33 and the second substrate 30 to form a switch structure 50. The switch structure 50 includes a single crystal silicon beam 321 and a protective layer 51 composed of a first sub-protective layer 31 and a second sub-protective layer 33 covering the single crystal silicon beam 321. The orthographic projections of the second driving electrode 41 and the second pole 42 on the second substrate 30 are located within the orthographic projection of the switch structure 50 on the second substrate 30, and one end of the switch structure 50 away from the second pole 42 is connected to the second substrate 30, and the other end is suspended.

[0046] Step S160: Bond the side of the second substrate 30 provided with the second electrode layer 40 to the side of the first substrate 10 provided with the first electrode layer 20, so that the orthographic projection of the first driving electrode 21 on the first substrate 10 overlaps with the orthographic projection of the second driving electrode 41 on the first substrate 10, and the orthographic projection of the first pole 22 on the first substrate 10 overlaps with the orthographic projection of the second pole 42 on the first substrate 10.

[0047] The switch structure of existing micromechanical switches usually uses a metal beam or a silicon nitride beam. When a micromechanical switch uses a metal beam, since the elastic modulus of the metal is large, a large force is required to bend and deform the metal beam, which makes the driving voltage required for the micromechanical switch large. This will not only increase the energy consumption of the micromechanical switch, but also limit its use in lower power consumption application scenarios. When a micromechanical switch uses a silicon nitride beam, residual stress is easily generated in the silicon nitride beam during the preparation process, causing the silicon nitride beam to bend, affecting the reliability and service life of the micromechanical switch. In addition, the elastic modulus of silicon nitride is also large, which will also increase the driving voltage required for the micromechanical switch.

[0048] The method for preparing a micromechanical switch provided in an embodiment of the present application utilizes a single crystal silicon layer 32 to prepare a single crystal silicon beam 321. The single crystal silicon beam 321 has an extremely high fatigue life, so that the micromechanical switch can be repeatedly opened and closed for a long time without significant performance degradation or failure. The elastic modulus of the single crystal silicon beam 321 is relatively small, so that the driving force required for the micromechanical switch is relatively small, thereby reducing the driving voltage and power consumption. Moreover, the method for preparing a micromechanical switch of the present application can directly obtain a switch structure 50 by etching the second substrate 30, thereby simplifying the process flow of the micromechanical switch and improving production efficiency. The protective layer 51 can effectively protect the single crystal silicon beam 321 and prevent the single crystal silicon beam 321 from being damaged during etching or other process flows, thereby facilitating improving the yield and reliability of the micromechanical switch. In one embodiment, as Figure 1 As shown, the first substrate 10 in step S100 is a single crystal silicon substrate, and step S100 further includes preparing an insulating dielectric layer 11 on the first substrate 10 by chemical vapor deposition.

[0049] In one embodiment, Figure 1 and Figure 2 As shown, before step S110, the preparation method further includes:

[0050] Using photoresist as a mask, dry-etching the insulating dielectric layer 11 to expose a partial area of ​​the first substrate 10;

[0051] The first substrate 10 is etched by using a silicon deep etching method to form a first through hole 101 and a second through hole 102, wherein the first through hole 101 and the second through hole 102 are both connected to a surface of the first substrate 10 where the first electrode layer is to be provided and another surface opposite to the surface;

[0052] Conductive metal is filled into the first through hole 101 and the second through hole 102 by sputtering and electroplating to form a first metal interconnection 103 and a second metal interconnection 104 .

[0053] By manufacturing the first metal interconnection 103 and the second metal interconnection 104 in the first substrate 10, the distance of signal transmission can be reduced, thereby reducing signal loss and delay, and the need for wire bonding can be reduced, saving chip area and improving integration. In addition, the first metal interconnection 103 and the second metal interconnection 104 can be directly connected to other components (such as a printed circuit board) through metal bumps, and the connection method is simple and reliable.

[0054] Furthermore, the first through hole 101 and the second through hole 102 are disposed perpendicular to the bottom surface of the first substrate 10 .

[0055] Furthermore, after forming the first metal interconnect 103 and the second metal interconnect 104, the other surface of the first substrate opposite to the surface where the first electrode layer is to be provided can be planarized by chemical mechanical polishing to remove excess conductive metal material generated by electroplating.

[0056] Furthermore, if Figure 2 As shown, before the first through hole 101 and the second through hole 102 are filled with metal to form the first metal interconnection 103 and the second metal interconnection 104, the preparation method further includes: preparing a first insulating layer 105 and a second insulating layer 106 on the inner wall of the first through hole 101 and the inner wall of the second through hole 102, respectively, and the materials of the first insulating layer 105 and the second insulating layer 106 can be insulating materials such as silicon dioxide. The first insulating layer 105 and the second insulating layer 106 can form an insulating layer on the inner wall of the through hole to prevent a short circuit between the first metal interconnection 103 or the second metal interconnection 104 and the first substrate 10, thereby ensuring the electrical performance of the metal interconnection is stable.

[0057] In one embodiment, Figure 3 As shown, in step S110 , the first electrode layer 20 is prepared on a side of the insulating dielectric layer 11 away from the first substrate 10 .

[0058] Furthermore, if Figure 3 As shown, step S110 also includes peeling off the first electrode layer 20 to form a third electrode 23 and a first sealing metal layer 24. The third electrode 23 is located on a side of the first driving electrode 21 away from the first electrode 22, and is spaced apart from the first driving electrode 21. The first sealing metal layer 24 is annular, and the orthographic projection of the first sealing metal layer 24 on the first substrate 10 surrounds the orthographic projections of the first driving electrode 21, the first electrode 22, and the third electrode 23 on the first substrate 10.

[0059] In some embodiments, the first electrode 22 is electrically connected to the second metal interconnection 104 , and the third electrode 23 is electrically connected to the first metal interconnection 103 .

[0060] In one embodiment, Figure 4 As shown, the second substrate 30 provided in step S120 may be a single crystal silicon substrate, and the first sub-protective layer 31 in step S130 may be a silicon dioxide protective layer. In step S130, the thickness of the first sub-protective layer 31 ranges from 500nm to 1000nm, and the thickness of the first sub-protective layer 31 may be, for example, 500nm, 750nm, 1000nm, etc. The thickness of the single crystal silicon layer 32 ranges from 2μm to 5μm, and the thickness of the single crystal silicon layer 32 may be, for example, 2μm, 3μm, 5μm, etc.

[0061] In one embodiment, Figure 5 As shown, in step S130, the single crystal silicon layer 32 may be etched by dry etching to form a single crystal silicon beam 321 and a single crystal silicon device layer 322. The single crystal silicon beam 321 and the single crystal silicon device layer 322 are spaced apart, and the single crystal silicon device layer 322 is annular, and its orthographic projection on the second substrate 30 surrounds the orthographic projection of the single crystal silicon beam 321 on the second substrate 30.

[0062] In one embodiment, Figure 6 As shown, in step S130, a second sub-protective layer 33 is deposited on the single crystal silicon layer 32 by chemical vapor deposition, and the second sub-protective layer 33 may be a silicon dioxide protective layer. The second sub-protective layer 33 may cover the single crystal silicon beam 321 and the single crystal silicon device layer 322. In some embodiments, the thickness of the second sub-protective layer 33 is 20% to 30% of the thickness of the single crystal silicon beam 321.

[0063] In one embodiment, Figure 7 As shown, in step S140, the second electrode layer 40 is processed by a metal stripping method to form a second driving electrode 41, a second pole 42, and a second sealing metal layer 43. The second sealing metal layer 43 is annular and is spaced apart from the second driving electrode 41 and the second pole 42. The orthographic projection of the second sealing metal layer 43 on the second substrate 30 surrounds the orthographic projections of the second driving electrode 41 and the second pole 42 on the second substrate 30.

[0064] In one embodiment, the material of the second electrode 42 is ruthenium, nickel or cobalt.

[0065] In one embodiment, Figure 8 As shown, after step S140 and before step S150, the preparation method further includes: preparing a support column 61 on a side of the second electrode layer 40 away from the second substrate 30 by an electroplating method, wherein the support column 61 is located at one end of the second driving electrode 41 away from the second pole 42.

[0066] Further, such as Figure 8As shown, the preparation method further includes preparing a sealing metal bonding layer 62 on the side of the second electrode layer 40 away from the second substrate 30 by an electroplating method. The sealing metal bonding layer 62 is annular, and the orthographic projection of the sealing metal bonding layer 62 on the second substrate 30 overlaps partly or completely with the orthographic projection of the second sealing metal layer 43 on the second substrate 30.

[0067] In some embodiments, the support column 61 has the same thickness as the sealing metal bonding layer 62 , and the thickness ranges from 3 μm to 6 μm. For example, the thickness may be 3 μm, 4 μm, 6 μm, etc.

[0068] In one embodiment, Fig. 9 and Fig.10 As shown, in step S150, etching the first sub-protection layer 31, the second sub-protection layer 33 and the second substrate 30 to form the switch structure 50 specifically includes:

[0069] A dry etching method is used to remove part of the material of the first sub-protection layer 31 and the second sub-protection layer 33 between the single crystal silicon device layer 322 and the single crystal silicon beam 321 to expose a part of the second substrate 30;

[0070] The exposed part of the second substrate 30 is used as an etching window, and the second substrate 30 is etched by an isotropic dry etching process to form a first cavity 71. The isotropic etching process can form the depth of the first cavity 71 while generating etching in a direction parallel to the upper surface of the second substrate 30, thereby removing the second substrate 30 under the single crystal silicon beam 321. By reducing the etching window on the side of the second driving electrode 41 away from the second pole 42, the etching speed of the part of the second substrate 30 covered by the orthographic projection of the support column 61 can be reduced, thereby forming a support structure 34 in the cavity 70 of the second substrate 30. In this process, a switch structure 50 with one end suspended can be formed, and the end of the switch structure 50 away from the second pole 42 is connected to the second substrate 30 through the unetched support structure 34.

[0071] The switch structure 50 is obtained by etching the second substrate 30 , and the first cavity 71 between the second substrate 30 and the switch structure 50 can increase the distance between the second substrate 30 and the first substrate 10 , which is beneficial to prevent the second substrate 30 from interfering with the electromagnetic field of the first pole 22 and the second metal interconnection 104 .

[0072] During the etching process, the first sub-protection layer 31 and the second sub-protection layer 33 form a protection layer 51 surrounding the single crystal silicon beam 321 , thereby preventing the single crystal silicon beam 321 from being damaged during the etching process of the second substrate 30 .

[0073] In some embodiments, the isotropic etching process is a xenon fluoride etching process.

[0074] In an implementation, such as Fig.11 As shown, in step S160, the process of bonding the side of the second substrate 30 provided with the second electrode layer 40 to the side of the first substrate 10 provided with the first electrode layer 20 specifically includes: aligning the sealing metal bonding layer 62 with the first sealing metal layer 24, aligning the support column 61 with the third electrode 23, and applying a certain temperature and pressure to the first substrate 10 and the second substrate 30 for metal bonding. After bonding, a second cavity 72 is formed between the side of the switch structure 50 provided with the second driving electrode 41 and the first substrate 10, and the second cavity 72 is connected with the first cavity 71 to form a vacuum cavity, so as to prevent dust and water vapor from entering and causing adverse effects on the micromechanical switch.

[0075] A driving voltage is applied to the first metal interconnection 103, and the driving voltage is applied to the second driving electrode 41 through the third electrode 23 and the support column 61. At this time, the first driving electrode 21 and the second driving electrode 41 generate electrostatic attraction, driving the switch structure 50 to bend toward the first substrate 10, so that the first electrode 22 contacts the second electrode 42, and finally the second metal interconnection 104 is turned on. After the driving voltage is removed, the electrostatic force disappears, the switch structure 50 rebounds, and the contact between the first electrode 22 and the second electrode 42 is disconnected.

[0076] The second driving electrode 41 and the second pole 42 are prepared on the side of the protective layer 51 facing the first substrate 10. When the first pole 22 and the second pole 42 are in contact to make the second metal interconnection 104 conductive, the protective layer 51 can isolate the second driving electrode 41 and the second pole 42 to prevent the control signal of the driving voltage of the first metal interconnection 103 from interfering with the signal transmission of the second metal interconnection 104.

[0077] The present application also provides a micromechanical switch, which is prepared by the above-mentioned preparation method. Fig.11 As shown, the micromechanical switch includes a first substrate 10 , a first electrode layer 20 , a second electrode layer 40 and a switch structure 50 .

[0078] The first electrode layer 20 is located on one side of the first substrate 10 , and the first electrode layer 20 includes a first driving electrode 21 and a first pole 22 spaced apart from the first driving electrode 21 .

[0079] The switch structure 50 is located on a side of the first electrode layer 20 away from the first substrate 10 and is spaced apart from the first electrode layer 20 . The switch structure 50 includes a single crystal silicon beam 321 and a protection layer 51 covering the single crystal silicon beam 321 .

[0080] The second electrode layer 40 is located on a side of the protection layer 51 facing the first electrode layer 20 . The second electrode layer 40 includes a second driving electrode 41 and a second electrode 42 spaced apart from the second driving electrode 41 .

[0081] The first driving electrode 21 can drive the second driving electrode 41 to drive the single crystal silicon beam 321 to deviate toward the direction close to the first substrate 10 , so that the first electrode 22 contacts the second electrode 42 .

[0082] In one embodiment, the micromechanical switch further comprises a second substrate 30 located on a side of the switch structure 50 away from the first substrate 10. An accommodation space for accommodating the single crystal silicon beam 321 is provided between the second substrate 30 and the first substrate 10. The second substrate 30 is connected to the first substrate 10 via a sealing metal bonding layer 62, and the sealing metal bonding layer 62 is used to seal the accommodation space.

[0083] In one embodiment, the first substrate 10 is provided with a first through hole 101 and a second through hole 102, the first through hole 101 and the second through hole 102 connect the surface of the first substrate 10 facing the switch structure 50 and the surface away from the switch structure 50, the first through hole 101 is provided with a first metal interconnection 103, the second through hole 102 is provided with a second metal interconnection 104, the first metal interconnection 103 is electrically connected to the second driving electrode 41, and the second metal interconnection 104 is electrically connected to the first electrode 22.

[0084] In one embodiment, a first insulating layer 105 is disposed between an inner wall of the first through hole 101 and the first metal interconnection 103 , and a second insulating layer 106 is disposed between an inner wall of the second through hole 102 and the second metal interconnection 104 .

[0085] In one embodiment, the material of the second electrode 42 is ruthenium, nickel or cobalt.

[0086] It should be noted that the technical solutions or technical features described in the above embodiments can be combined or supplemented with each other without causing conflicts. The scope of protection of this application is not limited to the precise structures described in the above embodiments and shown in the drawings; all modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection of this application.

Claims

1. A method for preparing a micromechanical switch, characterized in that: The preparation method comprises: providing a first substrate; A first electrode layer is prepared on one side of the first substrate, and the first electrode layer is peeled off to form a first driving electrode and a first pole spaced apart from the first driving electrode; providing a second substrate; A first sub-protective layer is prepared on one side of the second substrate, and a single crystal silicon layer is prepared on a side of the first sub-protective layer away from the second substrate; the single crystal silicon layer is etched to form a single crystal silicon beam; a second sub-protective layer is prepared on a side of the single crystal silicon layer away from the second substrate, and the orthographic projection of the second sub-protective layer on the second substrate covers the orthographic projection of the single crystal silicon beam on the second substrate; A second electrode layer is prepared on a side of the second sub-protection layer away from the second substrate; the second electrode layer is peeled off to form a second driving electrode and a second electrode spaced apart from the second driving electrode; The first sub-protective layer, the second sub-protective layer and the second substrate are etched to form a switch structure; the switch structure comprises a single crystal silicon beam and a protective layer consisting of a first sub-protective layer and a second sub-protective layer covering the single crystal silicon beam; the orthographic projections of the second driving electrode and the second pole on the second substrate are located within the orthographic projection of the switch structure on the second substrate; one end of the switch structure away from the second pole is connected to the second substrate, and the other end is suspended; The side of the second substrate provided with the second electrode layer is bonded to the side of the first substrate provided with the first electrode layer, so that the orthographic projection of the first driving electrode on the first substrate overlaps with the orthographic projection of the second driving electrode on the first substrate, and the orthographic projection of the first pole on the first substrate overlaps with the orthographic projection of the second pole on the first substrate.

2. The method for preparing a micromechanical switch according to claim 1, characterized in that: After preparing a second electrode layer on a side of the second sub-protection layer away from the second substrate and before etching to form the switch structure, the preparation method further includes: A support column is prepared on a side of the second driving electrode away from the second substrate, and the support column is located at an end of the second driving electrode away from the second electrode.

3. The method for preparing a micromechanical switch according to claim 2, characterized in that: Before preparing the first electrode layer on one side of the first substrate, the preparation method further includes: Etching the first substrate to form a first through hole and a second through hole, wherein the first through hole and the second through hole both connect a surface of the first substrate where the first electrode layer is to be disposed and another surface opposite to the surface; Metal is filled in the first through hole and the second through hole to form a first metal interconnect and a second metal interconnect; the first metal interconnect is used to be electrically connected to the second driving electrode through the support column; the second metal interconnect is used to be electrically connected to the first electrode.

4. The method for preparing a micromechanical switch according to claim 3, characterized in that: Before filling the first through hole and the second through hole with metal to form the first metal interconnection and the second metal interconnection, the preparation method further includes: A first insulating layer and a second insulating layer are respectively formed on the inner wall of the first through hole and the inner wall of the second through hole.

5. The method for preparing a micromechanical switch according to claim 1, characterized in that: After preparing a second electrode layer on a side of the second sub-protection layer away from the second substrate and before etching to form the switch structure, the preparation method further includes: A sealing metal bonding layer is prepared on a side of the second driving electrode away from the second substrate, and an orthographic projection of the sealing metal bonding layer on the second substrate is located outside an orthographic projection of the single crystal silicon beam on the second substrate.

6. A micromechanical switch, characterized in that: The micromechanical switch is prepared by the method for preparing a micromechanical switch according to any one of claims 1 to 5, and the micromechanical switch comprises: a first substrate; A first electrode layer, located at one side of the first substrate; the first electrode layer comprises a first driving electrode and a first pole spaced apart from the first driving electrode; a switch structure, located on a side of the first electrode layer away from the first substrate and spaced apart from the first electrode layer; the switch structure comprises a single crystal silicon beam and a protective layer covering the single crystal silicon beam; A second electrode layer is located on a side of the protective layer facing the first electrode layer; the second electrode layer comprises a second driving electrode and a second electrode spaced apart from the second driving electrode; The first driving electrode can drive the second driving electrode to drive the single crystal silicon beam to deviate toward the direction close to the first substrate, so that the first electrode contacts the second electrode.

7. The micromechanical switch according to claim 6, characterized in that: The micromechanical switch also includes a second substrate located on a side of the switch structure away from the first substrate; a receiving space for receiving the single crystal silicon beam is provided between the second substrate and the first substrate; the second substrate is connected to the first substrate via a sealing metal bonding layer, and the sealing metal bonding layer is used to seal the receiving space.

8. The micromechanical switch according to claim 6, characterized in that: The first substrate is provided with a first through hole and a second through hole; the first through hole and the second through hole connect the surface of the first substrate facing the switch structure and the surface away from the switch structure; a first metal interconnection is provided in the first through hole; a second metal interconnection is provided in the second through hole; the first metal interconnection is electrically connected to the second driving electrode, and the second metal interconnection is electrically connected to the first electrode.

9. The micromechanical switch according to claim 8, characterized in that: A first insulating layer is provided between the inner wall of the first through hole and the first metal interconnection; and a second insulating layer is provided between the inner wall of the second through hole and the second metal interconnection.

10. The micromechanical switch according to claim 6, characterized in that: The material of the second electrode is ruthenium, nickel or cobalt.

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