Method for manufacturing a micromechanical switch and micromechanical switch

Abstract

The application provides a preparation method of a micro mechanical switch and the micro mechanical switch. The preparation method of the micro mechanical switch comprises the following steps: providing a first substrate, and preparing a first electrode layer on one side of the first substrate. A second substrate is provided, a first sub-protection layer is prepared on one side of the second substrate, and a single crystal silicon layer is prepared on the side of the first sub-protection layer away from the second substrate. A second sub-protection layer is prepared on the side of the single crystal silicon layer away from the substrate. A second electrode layer is prepared on the side of the second sub-protection layer away from the second substrate. 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 pole on the second substrate is located in the orthographic projection of the switch structure layer on the second substrate. One end of the switch structure away from the second pole is connected with the second substrate, and the other end is suspended. The side of the second substrate provided with the second electrode layer is bonded with the side of the first substrate provided with the first electrode layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro-electro-mechanical devices, and particularly relates to a preparation method of a micro-mechanical switch and the micro-mechanical switch. BACKGROUND

[0002] The micro-mechanical switch is a mechanical structure switch with a size in the order of microns to millimeters realized by micro-nano manufacturing technology. The micro-mechanical switch has been widely applied in many fields such as radio frequency communication, optical communication, aerospace, etc. due to its small size, low power consumption, fast response speed, high reliability, and easy integration with existing integrated circuits.

[0003] The existing preparation method of the micro-mechanical switch has a low service life of the switch structure and a complex preparation method. SUMMARY

[0004] The present application provides a preparation method of a micro-mechanical switch and the micro-mechanical switch.

[0005] The first aspect of the present application provides a preparation method of a micro-mechanical switch, and the preparation method comprises the following steps.

[0006] A first substrate is provided;

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

[0008] A second substrate is provided;

[0009] A first sub-protection layer is prepared on one side of the second substrate, and a single crystal silicon layer is prepared on the side of the first sub-protection layer away from the second substrate; the single crystal silicon layer is etched to form a single crystal silicon beam; a second sub-protection layer is prepared on the side of the single crystal silicon layer away from the second substrate, and the orthographic projection of the second sub-protection 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 the side of the second sub-protection layer away from the second substrate; the second electrode layer is peeled to form a second driving electrode and a second pole spaced apart from the second driving electrode;

[0011] The first sub-protection layer, the second sub-protection layer, and the second substrate are etched to form a switch structure; the switch structure comprises a single crystal silicon beam and a protection layer composed of the first sub-protection layer and the second sub-protection layer covering the single crystal silicon beam; the orthographic projection of the second driving electrode and the second pole on the second substrate is 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] bonding one side of the second substrate provided with the second electrode layer with one side of the first substrate provided with the first electrode layer, so that the first driving electrode and the second driving electrode have an overlapping projection on the first substrate, and the first pole and the second pole have an overlapping projection on the first substrate.

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

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

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

[0016] the first substrate is etched to form a first through hole and a second through hole, both of which communicate the surface of the first substrate where the first electrode layer is needed to be arranged and the other surface opposite to the surface;

[0017] a first metal interconnection and a second metal interconnection are filled in the first through hole and the second through hole respectively; the first metal interconnection is used for electrically connecting the second driving electrode through the support column; and the second metal interconnection is used for electrically connecting the first pole.

[0018] In one embodiment, before the first metal interconnection and the second metal interconnection are filled in the first through hole and the second through hole, the preparation method further comprises:

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

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

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

[0022] The second aspect of the present application provides a micro-mechanical switch, which is prepared by the above preparation method, and the micro-mechanical switch comprises:

[0023] a first substrate;

[0024] a first electrode layer on 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 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 on a side of the protective layer facing the first electrode layer; the second electrode layer comprises a second driving electrode and a second pole 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 shift towards the first substrate, so that the first pole and the second pole are in contact.

[0028] In one embodiment, the micro-mechanical switch further comprises the second substrate on a side of the switch structure away from the first substrate; the second substrate and the first substrate are provided with a containing space for containing the single crystal silicon beam; the second substrate is connected with the first substrate through a sealing metal bonding layer, and the sealing metal bonding layer is used for sealing the containing 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 communicate the surface of the first substrate facing the switch structure and the surface of the first substrate away from the switch structure; the first through hole is provided with a first metal interconnection; the second through hole is provided with a second metal interconnection; the first metal interconnection is electrically connected with the second driving electrode, and the second metal interconnection is electrically connected with the first pole.

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

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

[0032] The preparation method of the micromechanical switch provided by the embodiment of the present application uses a single crystal silicon layer to prepare a single crystal silicon beam. The single crystal silicon beam has a very high fatigue life, so that the micromechanical switch can be repeatedly opened and closed for a long time without obvious performance degradation or failure. In addition, the elastic modulus of the single crystal silicon beam is small, so that the driving force required by the micromechanical switch is small, thereby the driving voltage can be reduced and the power consumption can be reduced. Moreover, the preparation method of the micromechanical switch of the present application can directly obtain the switch structure by etching the second substrate, so that the process flow of the micromechanical switch can be simplified, the production efficiency can be improved, and the protective layer can effectively protect the single crystal silicon beam, so as to avoid damage to the single crystal silicon beam in etching or other process flows, thereby the yield and reliability of the micromechanical switch can be improved.

[0033] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

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

[0035] Figures 1 to 11 The process flow chart of the preparation method of the micromechanical switch provided by an embodiment of the present application. DETAILED DESCRIPTION

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

[0037] If the embodiments of the present application involve directional indications or positional relationships (such as up, down, left, right, front, back, inner, outer, 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 condition, etc. between the components in a certain posture (as shown in the drawings); if the certain posture changes, the directional indication or positional relationship also changes accordingly. In addition, the terms "first", "second", etc. in the embodiments of the present application are only used for convenience of description, and cannot be understood as indicating or implying relative importance.

[0038] The preparation method of the micromechanical switch and the micromechanical switch of the embodiments of the present application will be described in detail below in conjunction with the accompanying drawings. In the case of no conflict, the features in the following embodiments and embodiments can be supplemented or combined with each other.

[0039] The embodiment of the present application provides a preparation method of a micro mechanical switch, as shown in the figure, the preparation method comprises the following steps: Figures 1 to 11

[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 stripping the first electrode layer 20 to form a first driving electrode 21 and a first pole 22 which is arranged in a spaced manner with the first driving electrode 21.

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

[0043] Step S130: preparing a first sub-protection layer 31 on one side of the second substrate 30, and preparing a single crystal silicon layer 32 on the side of the first sub-protection layer 31 which is away from the second substrate 30. The single crystal silicon layer 32 is etched to form a single crystal silicon beam 321. A second sub-protection layer 33 is prepared on the side of the single crystal silicon layer 32 which is away from the second substrate 30, and the orthographic projection of the second sub-protection 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 the side of the second sub-protection layer 33 which is away from the second substrate 30. The second electrode layer 40 is stripped to form a second driving electrode 41 and a second pole 42 which is arranged in a spaced manner with the second driving electrode 41.

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

[0046] Step S160: bonding the side of the second substrate 30 which is provided with the second electrode layer 40 with the side of the first substrate 10 which is 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 the existing micro-mechanical switch usually adopts a metal beam or a silicon nitride beam. When the micro-mechanical switch adopts the metal beam, a larger driving voltage is required for the micro-mechanical switch due to the larger elastic modulus of the metal, which not only increases the energy consumption of the micro-mechanical switch, but also limits the use of the micro-mechanical switch in a lower power consumption application scenario. When the micro-mechanical switch adopts the silicon nitride beam, residual stress is easily generated in the silicon nitride beam during the preparation process, thereby causing the beam body of the silicon nitride beam to bend, affecting the reliability and service life of the micro-mechanical switch, and the elastic modulus of the silicon nitride is also large, which also makes the driving voltage required for the micro-mechanical switch larger.

[0048] The preparation method of the micro-mechanical switch provided by the embodiments of the present application uses a single crystal silicon layer 32 to prepare a single crystal silicon beam 321, the single crystal silicon beam 321 has a very high fatigue life, so that the micro-mechanical 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 321 is smaller, so that the driving force required for the micro-mechanical switch is smaller, thereby the driving voltage can be reduced and the power consumption can be reduced. Moreover, the preparation method of the micro-mechanical switch of the present application can directly obtain the switch structure 50 by etching the second substrate 30, so that the process flow of the micro-mechanical switch can be simplified, the production efficiency can be improved, and the protective layer 51 can effectively protect the single crystal silicon beam 321, so as to avoid damage to the single crystal silicon beam 321 in etching or other process flows, thereby facilitating to improve the yield and reliability of the micro-mechanical switch. In one embodiment, as shown in Figure 1 The first substrate 10 in step S100 is a single crystal silicon substrate, and step S100 further includes preparing an insulating medium layer 11 above the first substrate 10 by a chemical vapor deposition method.

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

[0050] The insulating medium layer 11 is dry etched using a photoresist as a mask to expose part of the first substrate 10;

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

[0052] The first metal interconnection 103 and the second metal interconnection 104 are respectively filled in the first through hole 101 and the second through hole 102 by a sputtering and electroplating method using a conductive metal.

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

[0054] Further, the first via hole 101 and the second via hole 102 are vertically arranged with the bottom surface of the first substrate 10.

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

[0056] Further, as shown in Figure 2 Before the first via hole 101 and the second via hole 102 are filled with metal to form the first metal interconnect 103 and the second metal interconnect 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 via hole 101 and the second via hole 102 respectively. The material of the first insulating layer 105 and the second insulating layer 106 can be an insulating material 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 via hole, preventing short circuit between the first metal interconnect 103 or the second metal interconnect 104 and the first substrate 10, thus ensuring the stability of the electrical performance of the metal interconnect.

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

[0058] Further, as shown in Figure 3 Step S110 further includes stripping 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 the side of the first driving electrode 21 away from the first electrode 22, and is arranged 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 interconnect 104, and the third electrode 23 is electrically connected to the first metal interconnect 103.

[0060] In one embodiment, as shown inFigure 4 As shown in FIG. 1, the second substrate 30 provided in step S120 can be a single crystal silicon substrate, and the first sub-protection layer 31 in step S130 can be a silicon dioxide protection layer. In step S130, the thickness of the first sub-protection layer 31 can be in the range of 500 nm to 1000 nm, for example, the thickness of the first sub-protection layer 31 can be 500 nm, 750 nm, 1000 nm, etc. The thickness of the single crystal silicon layer 32 can be in the range of 2 μm to 5 μm, for example, the thickness of the single crystal silicon layer 32 can be 2 μm, 3 μm, 5 μm, etc.

[0061] In one embodiment, as shown in FIG. 1, in step S130, the single crystal silicon layer 32 can be etched by dry etching to form the single crystal silicon beam 321 and the single crystal silicon device layer 322. The single crystal silicon beam 321 and the single crystal silicon device layer 322 are spaced apart, the single crystal silicon device layer 322 is annular, and the orthographic projection of the single crystal silicon device layer 322 on the second substrate 30 encloses the orthographic projection of the single crystal silicon beam 321 on the second substrate 30. Figure 5 In one embodiment, as shown in FIG. 1, in step S130, the second sub-protection layer 33 can be deposited above the single crystal silicon layer 32 by chemical vapor deposition, and the second sub-protection layer 33 can be a silicon dioxide protection layer. The second sub-protection layer 33 can cover the single crystal silicon beam 321 and the single crystal silicon device layer 322. In some embodiments, the thickness of the second sub-protection layer 33 is 20% to 30% of the thickness of the single crystal silicon beam 321.

[0062] Figure 6 In one embodiment, as shown in FIG. 1, in step S130, the second sub-protection layer 33 can be deposited above the single crystal silicon layer 32 by chemical vapor deposition, and the second sub-protection layer 33 can be a silicon dioxide protection layer. The second sub-protection layer 33 can cover the single crystal silicon beam 321 and the single crystal silicon device layer 322. In some embodiments, the thickness of the second sub-protection layer 33 is 20% to 30% of the thickness of the single crystal silicon beam 321.

[0063] In one embodiment, as shown in FIG. 1, in step S140, the second electrode layer 40 can be processed by a metal stripping method to form the second driving electrode 41, the second electrode 42, and the second sealing metal layer 43. The second sealing metal layer 43 is annular and spaced apart from the second driving electrode 41 and the second electrode 42, and the orthographic projection of the second sealing metal layer 43 on the second substrate 30 encloses the orthographic projection of the second driving electrode 41 and the second electrode 42 on the second substrate 30. Figure 7 In one embodiment, the material of the second electrode 42 is ruthenium, nickel, or cobalt, etc.

[0064] In one embodiment, as shown in FIG. 1, after step S140 and before step S150, the preparation method further comprises: using an electroplating method to prepare a support column 61 on the side of the second electrode layer 40 away from the second substrate 30. The support column 61 is away from the second electrode 42 of the second driving electrode 41.

[0065] Figure 8 Further, as shown in FIG. 1, after step S140 and before step S150, the preparation method further comprises: using an electroplating method to prepare a support column 61 on the side of the second electrode layer 40 away from the second substrate 30. The support column 61 is away from the second electrode 42 of the second driving electrode 41.

[0066] Further, as shown in FIG. 1, after step S140 and before step S150, the preparation method further comprises: using an electroplating method to prepare a support column 61 on the side of the second electrode layer 40 away from the second substrate 30. The support column 61 is away from the second electrode 42 of the second driving electrode 41. Figure 8 ​​As shown, the preparation method further comprises preparing a sealing metal bonding layer 62 on the side of the second electrode layer 40 away from the second substrate 30 by using an electroplating method. The sealing metal bonding layer 62 is annular, and the orthogonal projection of the sealing metal bonding layer 62 on the second substrate 30 overlaps with part or all of the orthogonal projection of the second sealing metal layer 43 on the second substrate 30.

[0067] In some embodiments, the thickness of the support column 61 and the sealing metal bonding layer 62 is the same, and the thickness ranges from 3 μm to 6 μm, for example, the thickness can be 3 μm, 4 μm, 6 μm, etc.

[0068] In one embodiment, as shown in Figure 9 and Figure 10 As shown, the step S150 of 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 comprises:

[0069] The part 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 is etched and removed by using a dry etching method, so as to expose part of the second substrate 30;

[0070] The part of the second substrate 30 exposed by the second substrate 30 is used as an etching window, and the second substrate 30 is etched by using an isotropic dry etching process to form a first cavity 71. The isotropic etching process can form an etching direction parallel to the upper surface of the second substrate 30 while forming the depth of the first cavity 71, so as to remove the second substrate 30 below the single-crystal silicon beam 321. By reducing the etching window on the side of the second driving electrode 41 away from the second electrode 42, the etching speed of the part of the second substrate 30 covered by the orthogonal projection of the support column 61 can be reduced, so as to form a support structure 34 in the cavity 70 of the second substrate 30. In this process, the switch structure 50 with one end suspended can be formed, and the end of the switch structure 50 away from the second electrode 42 is connected to the second substrate 30 through the support structure 34 which is not etched.

[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 avoid the interference of the second substrate 30 on the electromagnetic field of the first electrode 22 and the second metal interconnection 104.

[0072] In 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, so as to avoid damaging the single-crystal silicon beam 321 in the process of etching the second substrate 30.

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

[0074] In an implementation, such as Figure 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 pillar 61 with the third electrode 23, and then 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 drive electrode 41 and the first substrate 10. The second cavity 72 is connected to the first cavity 71, forming a vacuum chamber, which can prevent dust and moisture from entering and adversely affecting the micromechanical switch.

[0075] A driving voltage is applied to the first metal interconnect 103, which is then applied to the second drive electrode 41 via the third electrode 23 and the support pillar 61. This generates an electrostatic attraction between the first drive electrode 21 and the second drive electrode 41, causing the switch structure 50 to bend toward the first substrate 10, bringing the first electrode 22 into contact with the second electrode 42, ultimately turning on the second metal interconnect 104. When the driving voltage is removed, the electrostatic force dissipates, causing the switch structure 50 to rebound, breaking contact between the first electrode 22 and the second electrode 42.

[0076] The second driving electrode 41 and the second electrode 42 are prepared on the side of the protective layer 51 facing the first substrate 10. When the first electrode 22 and the second electrode 42 contact to make the second metal interconnection 104 conductive, the protective layer 51 can isolate the second driving electrode 41 and the second electrode 42, thereby preventing 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 micro-mechanical switch, which is prepared by the above-mentioned preparation method. Figure 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] A second electrode layer 40 is located on a side of the protective layer 51 facing the first electrode layer 20, and the second electrode layer 40 comprises a second driving electrode 41 and a second pole 42 spaced 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 deflect towards the first substrate 10, so that the first pole 22 contacts the second pole 42.

[0082] In one embodiment, the micro-mechanical switch further comprises the second substrate 30 located on a side of the switch structure 50 away from the first substrate 10. The second substrate 30 and the first substrate 10 are provided with a receiving space for accommodating the single-crystal silicon beam 321. The second substrate 30 is connected to the first substrate 10 through a sealing metal bonding layer 62, and the sealing metal bonding layer 62 is used to seal the receiving space.

[0083] In one embodiment, the first substrate 10 is provided with a first through hole 101 and a second through hole 102, and the first through hole 101 and the second through hole 102 communicate the surface of the first substrate 10 facing the switch structure 50 and the surface of the first substrate 10 away from the switch structure 50. The first through hole 101 is provided with a first metal interconnection 103, and 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 pole 22.

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

[0085] In one embodiment, the material of the second pole 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 conflict, and the scope of protection of the present application is not limited to the precise structures described in the above embodiments and shown in the accompanying drawings. Modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A method of fabricating a micro-mechanical switch, characterized by, The preparation method comprises: providing a first substrate; preparing a first electrode layer on one side of the first substrate, and stripping the first electrode layer to form a first driving electrode and a first electrode spaced apart from the first driving electrode; providing a second substrate; preparing a first sub-protection layer on one side of the second substrate, preparing a single crystal silicon layer on the side of the first sub-protection layer away from the second substrate, etching the single crystal silicon layer to form a single crystal silicon beam, preparing a second sub-protection layer on the side of the single crystal silicon layer away from the second substrate, and the orthogonal projection of the second sub-protection layer on the second substrate covers the orthogonal projection of the single crystal silicon beam on the second substrate; preparing a second electrode layer on the side of the second sub-protection layer away from the second substrate, and stripping the second electrode layer to form a second driving electrode and a second electrode spaced apart from the second driving electrode; etching the first sub-protection layer, the second sub-protection layer and the second substrate to form a switching structure; the switching structure comprises a single crystal silicon beam and a protection layer composed of the first sub-protection layer and the second sub-protection layer covering the single crystal silicon beam; the orthogonal projection of the second driving electrode and the second electrode on the second substrate is located within the orthogonal projection of the switching structure on the second substrate; one end of the switching structure away from the second electrode is connected to the second substrate, and the other end is suspended; bonding the side of the second substrate provided with the second electrode layer to the side of the first substrate provided with the first electrode layer, so that the orthogonal projection of the first driving electrode on the first substrate overlaps with the orthogonal projection of the second driving electrode on the first substrate, and the orthogonal projection of the first electrode on the first substrate overlaps with the orthogonal projection of the second electrode on the first substrate.

2. The method of claim 1, wherein the micro-mechanical switch is formed by a process comprising: After preparing the second electrode layer on the side of the second sub-protection layer away from the second substrate, before etching to form the switching structure, the preparation method further comprises: preparing a support column on the side of the second driving electrode away from the second substrate, and the support column is located at one end of the second driving electrode away from the second electrode.

3. The method of claim 2, wherein the micro-mechanical switch is formed by a process comprising: Before preparing the first electrode layer on one side of the first substrate, the preparation method further comprises: etching the first substrate to form a first through hole and a second through hole, both of which communicate the surface of the first substrate where the first electrode layer is needed to be arranged and another surface opposite to the surface; filling metal in the first through hole and the second through hole respectively to form a first metal interconnection and a second metal interconnection; the first metal interconnection is used for electrically connecting the second driving electrode through the support column; and the second metal interconnection is used for electrically connecting the first electrode.

4. The method of claim 3, wherein the micro-mechanical switch is formed by a process comprising: Before filling metal in the first through hole and the second through hole to form a first metal interconnection and a second metal interconnection, the preparation method further comprises: respectively preparing a first insulating layer and a second insulating layer on the inner wall of the first through hole and the inner wall of the second through hole.

5. The method of claim 1, wherein the micro-machined switch is formed by a process comprising: After preparing the second electrode layer on the side of the second sub-protection layer away from the second substrate, before etching to form the switching structure, the preparation method further comprises: ​ A sealing metal bonding layer is prepared on a side of the second driving electrode away from the second substrate, a projection of the sealing metal bonding layer on the second substrate is located outside a projection of the single-crystal silicon beam on the second substrate.

6. A micromechanical switch, characterized by 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 on a 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 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 pole 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 shift towards the first substrate, so that the first pole and the second pole are in contact.

7. A micromechanical switch according to claim 6, characterised in that The micromechanical switch further comprises the second substrate located on a side of the switch structure away from the first substrate; the second substrate and the first substrate are provided with an accommodation space for accommodating the single-crystal silicon beam; the second substrate is connected to the first substrate through a sealing metal bonding layer, and the sealing metal bonding layer is used for sealing the accommodation space.

8. The micro-mechanical 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 communicate a surface of the first substrate facing the switch structure and a surface of the first substrate away from the switch structure; the first through hole is provided with a first metal interconnection; the second through hole is provided with a second metal interconnection; the first metal interconnection is electrically connected to the second driving electrode, and the second metal interconnection is electrically connected to the first pole.

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

10. The micro-mechanical switch of claim 6, wherein, The material of the second pole is ruthenium, nickel or cobalt.

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