Single-pole double-throw switch and preparation method thereof

Abstract

The invention provides a single-pole double-throw switch and a preparation method thereof, and relates to the technical field of micro-electro-mechanical radio frequency switches. The single-pole double-throw switch comprises a first layer structure, a suspended electrode and a second layer structure which are stacked. The first layer structure comprises a first substrate, a first driving electrode and a first contact, and the first driving electrode and the first contact are arranged on the side, close to the second layer structure, of the first substrate. The second layer structure comprises a second substrate, a second driving electrode and a second contact, and the second driving electrode and the second contact are arranged on the side, close to the first layer structure, of the second substrate. The suspended electrode is arranged between the first layer structure and the second layer structure, the single-pole double-throw switch further comprises a common input end, and the suspended electrode is connected with the common input end. And the suspended electrode is configured to be in contact with the first contact under the driving of the first driving electrode and to be in contact with the second contact under the driving of the second driving electrode. The three-dimensional stacked structure is beneficial to improving the integration level of the switch in a high-frequency system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro-electro-mechanical radio frequency switches, and in particular to a single-pole double-throw switch and a preparation method thereof. BACKGROUND

[0002] In recent years, radio frequency switches based on micro-electro-mechanical systems (MEMS) have become an important direction of research on high-performance radio frequency switches due to their simple structure, low power consumption, high operating frequency, small insertion loss, high isolation, and good linearity.

[0003] Most existing micro-electro-mechanical radio frequency switches (RF-MEMS) are mainly single-pole single-throw and have a planar structure, which has significant limitations in integrating multiple ports, achieving high-density packaging, and miniaturization, and it is difficult to fully utilize the three-dimensional spatial advantages of MEMS structures. In addition, due to the limited planar space, the design of leads, electrode isolation, driving response, and structure release process in a limited space also restricts the improvement of performance. SUMMARY

[0004] The present application provides a single-pole double-throw switch and a preparation method thereof, aiming to form a vertical stacked structure by innovative structural design and controllable manufacturing process, optimize structural layout, effectively save horizontal area, and improve the integration, reliability, and radio frequency performance of micro-electro-mechanical radio frequency switches in high-frequency systems.

[0005] To achieve the above-mentioned purposes, the embodiments of the present application provide the following technical solutions:

[0006] In a first aspect, a single-pole double-throw switch for a radio frequency MEMS is provided, which includes a first layer structure, a suspended electrode, and a second layer structure arranged in a stack.

[0007] The first layer structure includes a first substrate, a first drive electrode, and a first contact, and the first drive electrode and the first contact are arranged on the side of the first substrate close to the second layer structure.

[0008] The second layer structure includes a second substrate, a second drive electrode, and a second contact, and the second drive electrode and the second contact are arranged on the side of the second substrate close to the first layer structure.

[0009] The suspended electrode is arranged between the first layer structure and the second layer structure, and the single-pole double-throw switch further includes a common input terminal, and the suspended electrode is connected to the common input terminal. The suspended electrode is configured to be in contact with the first contact under the driving of the first drive electrode, and in contact with the second contact under the driving of the second drive electrode.

[0010] In some embodiments, the common input end comprises a first signal line, the first signal line is disposed on a side of the first substrate close to the second layer structure, and the overhanging electrode is electrically connected to the first signal line.

[0011] And / or, the common input end comprises a second signal line, the second signal line is disposed on a side of the second substrate close to the first layer structure, and the overhanging electrode is electrically connected to the second signal line.

[0012] In some embodiments, when the common input end comprises the first signal line, the first driving electrode is located between the first signal line and the first contact in a direction parallel to the first substrate, or the first contact is located between the first signal line and the first driving electrode.

[0013] And / or, when the common input end comprises the second signal line, the second driving electrode is located between the second signal line and the second contact in a direction parallel to the second substrate, or the second contact is located between the second signal line and the second driving electrode.

[0014] In some embodiments, the single-pole double-throw switch further comprises an anchor point, the anchor point is disposed between the first layer structure and the second layer structure.

[0015] When the common input end comprises the first signal line, the overhanging electrode is electrically connected to the first signal line through the anchor point.

[0016] And / or, when the common input end comprises the second signal line, the overhanging electrode is electrically connected to the second signal line through the anchor point.

[0017] In some embodiments, the anchor point comprises a first sub-anchor point and a second sub-anchor point. The first sub-anchor point is disposed between the overhanging electrode and the first signal line, and the overhanging electrode is integrally disposed with the first sub-anchor point. The second sub-anchor point is disposed between the overhanging electrode and the second signal line, and the overhanging electrode is bonded to the second sub-anchor point.

[0018] In some embodiments, the first layer structure further comprises a first bump, the first bump is disposed between the first substrate and the first contact. The second layer structure further comprises a second bump, the second bump is disposed between the second substrate and the second contact.

[0019] The second aspect further provides a preparation method of a single-pole double-throw switch, comprising the following steps S10-S30:

[0020] Step S10: forming a first driving electrode and a first contact on a first substrate to form a first layer structure, and forming a second driving electrode and a second contact on a second substrate to form a second layer structure.

[0021] Step S20: forming an overhanging electrode on the first layer structure.

[0022] Step S30: disposing the second layer structure on the side of the overhanging electrode away from the first layer structure.

[0023] The single-pole double-throw switch further comprises a common input end, and the overhanging electrode is connected to the common input end. The overhanging electrode is configured to be in contact with the first contact under the driving of the first driving electrode, and in contact with the second contact under the driving of the second driving electrode.

[0024] In some embodiments, the first layer structure is formed, including steps S111-S113:

[0025] Step S111: forming the first driving electrode on the first substrate.

[0026] Step S112: forming the first isolation layer on the first driving electrode.

[0027] Step S113: forming the first signal line and the first contact, the first driving electrode being located between the first signal line and the first contact, or the first contact being located between the first signal line and the first driving electrode in a direction parallel to the first substrate.

[0028] The second layer structure is formed, including steps S121-S123:

[0029] Step S121: forming the second driving electrode on the second substrate.

[0030] Step S122: forming the second isolation layer on the second driving electrode.

[0031] Step S123: forming the second signal line and the second contact, the second driving electrode being located between the second signal line and the second contact, or the second contact being located between the second signal line and the second driving electrode in a direction parallel to the second substrate.

[0032] In some embodiments, the overhanging electrode is formed on the first layer structure, including steps S21-S23:

[0033] Step S21: forming a sacrificial layer on the first layer structure, the sacrificial layer comprising a through hole.

[0034] Step S22: forming a first sub-anchor point in the through hole, and forming an electrode on the sacrificial layer, the electrode being integrally arranged with the first sub-anchor point.

[0035] Step S23: removing the sacrificial layer to form the overhanging electrode.

[0036] Before disposing the second layer structure on the side of the overhanging electrode away from the first layer structure, further comprising: forming a second sub-anchor point on the second layer structure.

[0037] The second layer structure is arranged on the side of the overhanging electrode away from the first layer structure, including: bonding the second layer structure to the side of the overhanging electrode away from the first layer structure through the second sub-anchor point.

[0038] In some embodiments, before the first contact is formed, a first bump is further formed on the first substrate. After the first contact is formed, the first contact is located on the side of the first bump away from the first substrate.

[0039] Before the second contact is formed, a second bump is further formed on the second substrate. After the second contact is formed, the second contact is located on the side of the second bump away from the second substrate.

[0040] In the embodiments provided in the present application, the first layer structure, the overhanging electrode and the second layer structure are stacked, the overhanging electrode is arranged between the first layer structure and the second layer structure and connected to the common input end of the single-pole double-throw switch. The first contact in the first layer structure can be used as the first output end of the single-pole double-throw switch, and the second contact in the second layer structure can be used as the second output end of the single-pole double-throw switch. Under the driving of the first driving electrode, the overhanging electrode is in contact with the first contact, so that the conduction between the common input end and the first output end is realized. Under the driving of the second driving electrode, the overhanging electrode is in contact with the second contact, so that the conduction between the common input end and the second output end is realized. In the present application, the single-pole double-throw switch forms a three-dimensional stacked structure, and the two output ends are arranged opposite to each other in the vertical direction, which fully utilizes the vertical space to optimize the structure layout, is conducive to realizing electrode isolation and lead design, is conducive to reducing the planar area, and improves the integration, reliability and radio frequency performance of the micro-electromechanical radio frequency switch in a high-frequency system.

[0041] The preparation method has simple process, is easy to implement, has strong process compatibility, is conducive to improving production efficiency and reducing manufacturing cost, and is conducive to realizing design and manufacturing of high-precision micro-nano structures. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the present application, the following will briefly introduce the drawings needed to be used in some embodiments of the present application. Obviously, the drawings in the following description are only some drawings of the embodiments of the present application, and other drawings can also be obtained by those skilled in the art according to these drawings. In addition, the drawings in the following description can be regarded as schematic diagrams, and are not the actual size of the product involved in the embodiments of the present application or the actual flow of the method.

[0043] Figure 1 The circuit symbol diagram of the single-pole double-throw switch;

[0044] Figure 2 The structural schematic diagram of the single-pole double-throw switch provided in the embodiments of the present application;

[0045] Figure 3 Another structure schematic diagram of a single-pole double-throw switch provided by an embodiment of the present application is shown in the figure.

[0046] Figure 4 A flow chart of a preparation method of a single-pole double-throw switch provided by an embodiment of the present application is shown in the figure.

[0047] Figures 5 to 14 For Figure 4 The figure shows each step of the preparation method. DETAILED DESCRIPTION

[0048] The technical solutions in some embodiments of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments provided by the present application, all other embodiments obtained by those skilled in the art belong to the scope of protection of the present application.

[0049] Unless otherwise required by the context, throughout the specification and claims, the term "comprising" is to be interpreted as open, inclusive, meaning "including, but not limited to".

[0050] Hereinafter, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, unless otherwise stated, the meaning of "multiple" is two or more.

[0051] In describing some embodiments, the term "connected" and its derivatives can be used. The term "connected" should be interpreted broadly, for example, "connected" can be fixedly connected, or detachably connected, or integrated; can be directly connected, or indirectly connected through an intermediate medium. For example, in describing some embodiments, the term "connected" can be used to indicate that two or more components have direct physical or electrical contact with each other.

[0052] In addition, the use of "based on" means open and inclusive, because the process, step, calculation or other action "based on" one or more stated conditions or values can be based on additional conditions or values beyond those stated in practice.

[0053] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can be that the layer or element is directly on the other layer or substrate, or there can be an intermediate layer between the layer or element and the other layer or substrate.

[0054] Exemplary embodiments are described herein with reference to cross-sectional illustrations that are idealized examples. In the drawings, the thickness of layers and regions are exaggerated for clarity. Accordingly, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and / or tolerances, are to be expected. Thus, the exemplary embodiments should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an etched region illustrated as a rectangle will typically have rounded or curved features. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region of a device and are not intended to limit the scope of the exemplary embodiments.

[0055] Currently, with the continuous progress of information technology, modern communication systems are rapidly developing towards high frequency, high bandwidth and multi-functional integration. The rise of technologies such as the fifth generation mobile communication (5G), millimeter wave communication, radar system, satellite navigation, reconfigurable antenna and smart terminal puts forward higher performance requirements for radio frequency front-end devices. Among numerous key devices, radio frequency switch, as an important component to realize signal selection, path switching and channel control, its performance directly affects the efficiency, reliability and power consumption of the whole communication system. Traditional radio frequency switch technology is mainly based on semiconductor process, such as PIN diode and CMOS field effect transistor (FET) etc. Although such switches have the advantages of fast response speed, low driving voltage and mature process, etc., but their high-frequency insertion loss, low isolation, poor linearity and high power consumption, etc. seriously restrict their further application in the new generation of communication systems. Especially in the frequency band of 10 GHz and above, the traditional switch has been difficult to meet the comprehensive requirements of low power consumption, low loss and high isolation, etc.

[0056] In recent years, radio frequency switch based on micro-electro-mechanical system (MEMS) has become an important direction of high-performance radio frequency switch research due to its simple structure, extremely low power consumption, high working frequency, small insertion loss, high isolation and good linearity, etc. Compared with traditional semiconductor switches, its radio frequency performance in a wide frequency band is better, and it is an ideal choice to realize high-performance, low-power-consumption and high-integration radio frequency modules.

[0057] However, most of the existing radio frequency MEMS switches are planar structures, and mainly single-pole single-throw (SPST). This planar layout structure has significant limitations in integrating multiple ports, realizing high-density packaging and miniaturization, and it is difficult to fully exert the three-dimensional spatial advantages of MEMS structure. In addition, due to the limitation of planar space, the lead design, electrode isolation, driving response and structure release process in limited space also restrict the performance improvement.

[0058] Based on this, the present application provides a single-pole double-throw switch of a radio frequency MEMS, such asFigures 1 to 3 As shown, Figure 1 This is the circuit symbol diagram of a single-pole double-throw switch. Figure 2 This is a schematic diagram of the structure of a single-pole double-throw switch provided in an embodiment of the present application. Figure 3 A schematic structural diagram of another single-pole double-throw switch provided in an embodiment of the present application.

[0059] like Figure 1 As shown, the single-pole double-throw switch includes a common input terminal IN and two output terminals, which are respectively denoted as a first output terminal OUT1 and a second output terminal OUT2.

[0060] like Figure 2 As shown, the single-pole double-throw switch includes a stacked first structure 10, a suspended electrode 30, and a second structure 20. The suspended electrode 30 is disposed between the first structure 10 and the second structure 20 and connected to a common input terminal IN.

[0061] The first layer structure 10 includes a first substrate 11, a first drive electrode 12, and a first contact 13. The first drive electrode 12 and the first contact 13 are both disposed on a side of the first substrate 11 close to the second layer structure 20. That is, the first contact 13 is disposed on a side close to the suspended electrode 30. The first contact 13 here can serve as the first output terminal OUT1 of the single-pole double-throw switch.

[0062] The suspended electrode 30 is configured to contact the first contact 13 under the drive of the first drive electrode 12. Exemplarily, the material of the first drive electrode 12 includes gold, aluminum, titanium, chromium, tungsten, molybdenum, or platinum. Applying a drive voltage to the first drive electrode 12 generates an electrostatic force between the suspended electrode 30 and the first drive electrode 12, the magnitude of which is related to the magnitude of the applied voltage. When the electrostatic force is greater than the elastic restoring force of the suspended electrode 30, the suspended electrode 30 bends toward the first layer structure 10 until it contacts the first contact 13, thereby achieving conduction between the common input terminal IN and the first output terminal OUT1.

[0063] That is, the first driving electrode 12 can drive the suspended electrode 30 under nanosecond voltage loading to make it contact or disconnect with the first contact 13, thereby turning on or off the radio frequency signal of the first output terminal OUT1.

[0064] The second layer structure 20 includes a second substrate 21, a second drive electrode 22, and a second contact 23. The second drive electrode 22 and the second contact 23 are both disposed on a side of the second substrate 21 close to the first layer structure 10. That is, the second contact 23 is disposed on a side close to the suspended electrode 30. The second contact 23 here can serve as the second output terminal OUT2 of the single-pole double-throw switch.

[0065] The suspended electrode 30 is also configured to contact the second contact 23 under the driving of the second driving electrode 22. Referring to the working principle described above, the material of the second driving electrode 22 includes gold, aluminum, titanium, chromium, tungsten, molybdenum or platinum, for example. When a driving voltage is applied to the second driving electrode 22, an electrostatic force is generated between the suspended electrode 30 and the second driving electrode 22, and the magnitude of the electrostatic force is related to the magnitude of the applied voltage. When the electrostatic force is greater than the elastic restoring force of the suspended electrode 30, the suspended electrode 30 bends towards the second layer structure 20 until it contacts the second contact 23, thereby realizing the conduction between the common input IN and the second output OUT2.

[0066] That is, the second driving electrode 22 can drive the suspended electrode 30 to contact or disconnect the second contact 23 under nanosecond voltage loading, thereby realizing the conduction or cutoff of the radio frequency signal of the second output OUT2.

[0067] In summary, in the embodiments of the present application, the single-pole double-throw switch has a three-dimensional stacked structure, and the two outputs and the common input form a sandwich-type vertical structure. The two outputs are arranged opposite to each other in the vertical direction, and the first driving electrode 12 and the second driving electrode 22 serve as two control terminals of the single-pole double-throw switch, respectively. Under the electrostatic driving action, the suspended electrode 30 bends upwards or downwards, thereby realizing the single-pole double-throw function.

[0068] In the present application, the single-pole double-throw switch makes full use of the vertical space to optimize the structure layout, which is conducive to realizing the electrical isolation between the common input IN, the first output OUT1 and the second output OUT2, optimizing the lead design using the vertical space, reducing the planar area, and improving the integration, reliability and radio frequency performance of the micro-electromechanical radio frequency switch in a high-frequency system.

[0069] In some embodiments, as shown in FIG. 1, the common input IN includes a first signal line 14 arranged on the side of the first substrate 11 close to the second layer structure 20, and the suspended electrode 30 is electrically connected to the first signal line 14. Figure 2

[0070] Alternatively, the common input IN includes a second signal line 24 arranged on the side of the second substrate 21 close to the first layer structure 10, and the suspended electrode 30 is electrically connected to the second signal line 24.

[0071] Alternatively, the common input IN includes both the first signal line 14 and the second signal line 24.

[0072] ​The first signal line 14 or the second signal line 24 can be used to realize the electrical connection of the single-pole double-throw switch and an external circuit, that is, the input signal can be input to the single-pole double-throw switch through the first signal line 14 or the second signal line 24. The common input terminal IN includes both the first signal line 14 and the second signal line 24, which is conducive to the application of the single-pole double-throw switch in a more complex circuit environment, and is conducive to realizing multi-port integration and high-density packaging.

[0073] The first signal line 14 can be prepared in the same process and by using the same material as the first contact 13, and the second signal line 24 can be prepared in the same process and by using the same material as the second contact 23. For example, the materials of the first signal line 14 and the first contact 13, and the second signal line 24 and the second contact 23 include gold, titanium, aluminum or polysilicon, which all have good conductivity and can be selected and optimized according to different application environments to enhance the adaptability and customizability of the device.

[0074] In some embodiments, as shown in FIG. 1, when the common input terminal IN includes the first signal line 14, the first driving electrode 12 is located between the first signal line 14 and the first contact 13 in a direction parallel to the first substrate 11, or, as shown in FIG. 2, the first contact 13 is located between the first signal line 14 and the first driving electrode 12. Figure 2 Figure 3

[0075] It can be understood that the overhanging electrode 30 includes opposite first and second ends. Taking the example that the first end of the overhanging electrode 30 is electrically connected to the common input terminal IN, “the first driving electrode 12 is located between the first signal line 14 and the first contact 13” can be correspondingly understood as that the electrostatic force provided by the first driving electrode 12 mainly acts on the middle part of the overhanging electrode 30 to drive the overhanging electrode 30 to bend, so that the second end of the overhanging electrode 30 is electrically connected to the first contact 13. The first signal line 14 and the first contact 13 are arranged on the two sides of the first driving electrode 12, which is conducive to realizing the electrical isolation between the first signal line 14 and the first contact 13 and avoiding short circuit. The second end of the overhanging electrode 30 has a larger bending amplitude than the middle part, and is more likely to realize electrical connection.

[0076] And “the first contact 13 is located between the first signal line 14 and the first driving electrode 12” can be correspondingly understood as that the electrostatic force provided by the first driving electrode 12 mainly acts on the second end of the overhanging electrode 30 to drive the overhanging electrode 30 to bend, so that the middle part of the overhanging electrode 30 is electrically connected to the first contact 13. Based on this, in the same bending amplitude, the electrostatic force required in the embodiment is smaller, and the same bending amplitude can be realized by applying a smaller voltage to the first driving electrode 12, which is conducive to reducing power consumption.

[0077] ​​Similarly, in the case where the common input terminal includes the second signal line 24, as shown in FIG. Figure 2 As shown, the second driving electrode 22 is located between the second signal line 24 and the second contact 23 in a direction parallel to the second substrate 21. This facilitates electrical isolation between the second signal line 24 and the second contact 23 and prevents short circuits. During operation, the electrostatic force provided by the second driving electrode 22 mainly acts on the middle portion of the suspended electrode 30, driving the suspended electrode 30 to bend, thereby electrically connecting the second end of the suspended electrode 30 to the second contact 23. Alternatively, as Figure 3 As shown, the second contact 23 is located between the second signal line 24 and the second driving electrode 22. During operation, the electrostatic force provided by the second driving electrode 22 mainly acts on the second end of the suspended electrode 30, driving the suspended electrode 30 to bend, thereby electrically connecting the middle portion of the suspended electrode 30 to the second contact 23. A smaller voltage can be applied to the second driving electrode 22 to achieve the same bending amplitude, which is beneficial to reducing power consumption.

[0078] In some embodiments, as Figures 2 to 3 As shown, the single-pole double-throw switch further includes an anchor point 40 , which is disposed between the first structure 10 and the second structure 20 .

[0079] Anchors 40 provide support and fixation to achieve a vertical sandwich structure of the first layer 10, suspended electrode 30, and second layer 20. For example, the first end of suspended electrode 30 is connected to anchor 40, which secures suspended electrode 30 between first layer 10 and second layer 20 and ensures that the middle portion and second end of suspended electrode 30 remain suspended.

[0080] Anchor point 40 is positioned between first layer structure 10 and second layer structure 20. This sandwich-like vertical structure further enhances connection reliability at anchor point 40 during bending of suspended electrode 30. For example, when suspended electrode 30 bends toward first contact 13, second layer structure 20 improves the connection reliability between anchor point 40 and first layer structure 10, preventing breakage between the two and thus ensuring a reliable electrical connection between suspended electrode 30 and common input terminal IN. The same applies when suspended electrode 30 bends toward second contact 23, and further explanation is omitted here.

[0081] The anchor point 40 is also conductive. When the common input terminal includes the first signal line 14, the suspended electrode 30 is electrically connected to the first signal line 14 through the anchor point 40. When the common input terminal includes the second signal line 24, the suspended electrode 30 is electrically connected to the second signal line 24 through the anchor point 40.

[0082] Illustratively, anchor point 40 and suspended electrode 30 are made of the same material, including gold, titanium, aluminum, or polysilicon, all of which have excellent electrical conductivity. External signals are electrically connected to common input terminal IN, transmitted through anchor point 40 to suspended electrode 30, and then output through the output terminal in the on state. In other words, anchor point 40 not only ensures structural stability of the single-pole double-throw switch, but also ensures a reliable electrical connection between suspended electrode 30 and common input terminal IN, thereby facilitating switch conductivity.

[0083] In some embodiments, as Figures 2 to 3 As shown, the anchor point 40 includes a first sub-anchor point 41 and a second sub-anchor point 42. The first sub-anchor point 41 is disposed between the suspended electrode 30 and the first signal line 14, and the suspended electrode 30 and the first sub-anchor point 41 are integrally disposed. The second sub-anchor point 42 is disposed between the suspended electrode 30 and the second signal line 24, and the suspended electrode 30 and the second sub-anchor point 42 are bonded to each other.

[0084] That is, the suspended electrode 30 is electrically connected to the first signal line 14 via the first sub-anchor 41, and is electrically connected to the second signal line 24 via the second sub-anchor 42. The suspended electrode 30 and the first sub-anchor 41 are integrally provided, and the suspended electrode 30 and the second sub-anchor 42 are bonded together. In other words, the suspended electrode 30 and the first sub-anchor 41 can be manufactured using the same process and the same materials, and then bonded together with the second sub-anchor 42. This not only simplifies the process and improves process feasibility, but also improves the stability of the suspended electrode 30.

[0085] In some embodiments, as Figures 2 to 3 As shown, the first layer structure 10 further includes a first bump 15 disposed between the first substrate 11 and the first contact 13 . The second layer structure 20 further includes a second bump 25 disposed between the second substrate 21 and the second contact 23 .

[0086] The provision of the first bump 15 reduces the distance between the first contact 13 and the suspended electrode 30. Similarly, the provision of the second bump 25 reduces the distance between the second contact 23 and the suspended electrode 30. When the suspended electrode 30 undergoes a small bending deformation, conduction between the common input terminal IN and the output terminal OUT can be achieved. Based on this, applying a small driving voltage to the first driving electrode 12 can achieve conduction of the switch, which is beneficial for reducing power consumption. In addition, during the process of switching from the off state to the on state, the deformation of the suspended electrode 30 is small, the bending performance requirements of the suspended electrode 30 are low, and it is beneficial for improving the service life of the suspended electrode 30.

[0087] In a second aspect, a method for preparing a single-pole double-throw switch is also provided. Figure 4 As shown, Figure 4A flow chart of a method for preparing a single-pole double-throw switch provided in an embodiment of the present application is provided. Figures 5 to 14 for Figure 4 Diagram of each step of the preparation method shown.

[0088] The preparation method includes the following steps S10 to S30:

[0089] Step S10: Figures 5 to 8 As shown, a first driving electrode 12 and a first contact 13 are formed on a first substrate 11 to form a first layer structure 10 , and a second driving electrode 22 and a second contact 23 are formed on a second substrate 21 to form a second layer structure 20 .

[0090] For example, taking the first layer structure 10 as an example, the first substrate 11 is a silicon wafer, the thickness of which ranges from 100μm to 1000μm, the plane diameter of the silicon wafer ranges from 4 inches to 12 inches, and the conductivity type of the silicon wafer can be N-type or P-type.

[0091] In some embodiments, forming the first layer structure 10 includes the following steps S111 to S113:

[0092] Step S111: Figures 5 to 6 As shown, a first driving electrode 12 is formed on a first substrate 11 .

[0093] For example, a metal film is deposited on a silicon wafer using a thin film deposition technique (such as chemical vapor deposition technique or physical vapor deposition technique), and then the metal film is patterned using photolithography and etching techniques to ultimately form the first driving electrode 12 .

[0094] The thickness of the metal film ranges from 10nm to 10μm. The material of the metal film includes gold, aluminum, titanium, chromium, tungsten, molybdenum or platinum. The etching technology includes dry etching or wet etching. Along the conduction direction of the switch, after patterning, the length of the first driving electrode 12 ranges from 100nm to 10μm.

[0095] Step S112: Figure 7 As shown, a first isolation layer 16 is formed on the first driving electrode 12 .

[0096] For example, low-pressure chemical vapor deposition, plasma-enhanced chemical vapor deposition or atmospheric pressure chemical vapor deposition technology is used to form a first isolation layer 16 on the side of the first driving electrode 12 away from the first substrate 11. The thickness of the first isolation layer 16 is in the range of 10 nm to 10 μm, and the material of the first isolation layer 16 includes silicon oxide or silicon nitride.

[0097] Step S113: Figure 8 As shown, a first signal line 14 and a first contact 13 are formed.

[0098] For example, a photoresist mask is formed, and a conductive film is formed on the first isolation layer 16 through magnetron sputtering, electron beam evaporation, electroplating, or low-pressure chemical vapor deposition. The thickness of the conductive film ranges from 10 nm to 10 μm, and the conductive film material may include gold, titanium, aluminum, or polysilicon. Excessive portions of the conductive film are then removed through photolithography and lift-off techniques, ultimately forming the separated first signal line 14 and first contact 13. The length of the first contact 13 in the on-direction of the switch ranges from 100 nm to 10 μm.

[0099] Along the direction parallel to the first substrate 11, such as Figure 8 As shown, the first driving electrode 12 is located between the first signal line 14 and the first contact 13. Figure 3 As shown, the first contact 13 is located between the first signal line 14 and the first driving electrode 12 .

[0100] Similarly, forming the second layer structure 20 includes steps S121 to S123:

[0101] Step S121: Figures 5 to 6 As shown, the second driving electrode 22 is formed on the second substrate 21.

[0102] Step S122: Figure 7 As shown, a second isolation layer 27 is formed on the second driving electrode 22 .

[0103] Step S123: Figure 8 As shown, a second signal line 24 and a second contact 23 are formed, and the second driving electrode 22 is located between the second signal line 24 and the second contact 23 along a direction parallel to the second substrate 21, or, see Figure 3 As shown, the second contact 23 is located between the second signal line 24 and the second driving electrode 22 .

[0104] The preparation method of the second layer structure 20 is similar to the preparation method of the first layer structure 10 , and each preparation step refers to the preparation method of the first layer structure 10 described above, which will not be repeated here.

[0105] Step S20: Figures 9 to 11 As shown, the suspended electrode 30 is formed on the first layer structure 10 .

[0106] Exemplarily, forming the suspended electrode 30 on the first layer structure 10 includes the following steps S21 to S23:

[0107] Step S21: Figure 9 As shown, a sacrificial layer 17 is formed on the first layer structure 10 , and the sacrificial layer 17 includes a penetrating through hole.

[0108] For example, the material of the sacrificial layer 17 includes polyimide. The polyimide is spin-coated on the first layer structure 10 and is pre-cured. Then, a through hole is formed on the sacrificial layer 17 by using a photolithography technique and a developing technique, and the through hole exposes the first signal line 14. Optionally, the thickness of the sacrificial layer 17 ranges from 10 nm to 10 μm, and the length of the through hole ranges from 100 nm to 10 μm along the on direction of the switch.

[0109] Step S22: As shown in the figure, a first sub-anchor point 41 is formed in the through hole, and an electrode 30 is formed on the sacrificial layer 17, and the electrode 30 is integrally arranged with the first sub-anchor point 41. Figure 10

[0110] For example, a photoresist is spin-coated, and a photoresist pattern is formed by using a photolithography technique and a developing technique. Then, a conductive material (for example, gold, titanium, aluminum or polysilicon) is grown in the through hole and on the sacrificial layer 17 by using a magnetron sputtering, an electron beam evaporation, an electroplating or a low pressure chemical vapor deposition technique. After stripping the photoresist, a surface polishing is performed by using a planarization technique, and finally the first sub-anchor point 41 and the electrode 30 are formed, and the electrode 30 is integrally arranged with the first sub-anchor point 41, wherein the part of the electrode 30 in the through hole is the first sub-anchor point 41.

[0111] That is, along the on direction of the switch, the length of the first sub-anchor point 41 is the same as the length of the through hole, and the length of the first sub-anchor point 41 ranges from 100 nm to 10 μm. The length of the first sub-anchor point 41 is relatively long, which is beneficial to improve the structural stability. The thickness of the first sub-anchor point 41 is the same as the thickness of the sacrificial layer 17, and the thickness of the first sub-anchor point 41 ranges from 10 nm to 10 μm. The height of the electrode ranges from 10 nm to 10 μm (it can be understood that the thickness of the conductive material grown in the through hole is at least 20 nm). Along the on direction of the switch, the length of the electrode 30 ranges from 100 nm to 100 μm. The length of the electrode 30 needs to be ensured to be able to be subjected to the electrostatic force of the first driving electrode 12, and the electrode 30 can be reliably electrically connected with the first contact 13 under the action of the electrostatic force.

[0112] Step S23: As shown in the figure, the sacrificial layer 17 is removed to form the suspended electrode 30. Figure 11

[0113] For example, a dry etching or a wet etching process is used to release the sacrificial layer 17, so that one end of the electrode 30 is fixed on the first layer structure 10 through the first sub-anchor point 41, and the other end of the electrode 30 is in a suspended state.

[0114] Step S30: As shown in the figure, the second layer structure 20 is arranged on the side of the suspended electrode 30 away from the first layer structure 10. Figures 12 to 14

[0115] ​​​The SPDT switch further includes a common input terminal IN, to which the suspended electrode 30 is connected. The suspended electrode 30 is configured to contact the first contact 13 when driven by the first driving electrode 12 and to contact the second contact 23 when driven by the second driving electrode 22.

[0116] Exemplarily, to achieve the final sandwich-type vertical structure, the second layer structure 20 is disposed before the suspended electrode 30 on a side away from the first layer structure 10 , and further includes: forming a second sub-anchor point 42 on the second layer structure 20 .

[0117] like Figure 9 As shown, a sacrificial layer 27 is formed on the second layer structure 20 . The sacrificial layer 27 includes a through hole extending therethrough. The through hole includes the second signal line 24 .

[0118] Then as Figure 12 As shown, refer to Figure 10 Correspondingly, a second sub-anchor point 42 is formed in the through hole.

[0119] Afterwards Figure 13 As shown, refer to Figure 11 Correspondingly, the sacrificial layer 27 is removed, and finally the second sub-anchor point 42 is formed on the second layer structure 20 .

[0120] Finally, if Figure 14 As shown, the second layer structure 20 is arranged on the side of the suspended electrode 30 away from the first layer structure 10. For example, the second layer structure 20 is bonded to the side of the suspended electrode 30 away from the first layer structure 10 through the second sub-anchor point 42. The bonding method includes hot pressing bonding, diffusion bonding, ultrasonic bonding or surface activation bonding.

[0121] Thus, a three-dimensional stacked structure of the first layer structure 10 , the suspended electrode 30 , and the second layer structure 20 may be formed.

[0122] The above-mentioned fabrication method is simple and easy to implement, and its dimensions and structure are precisely controllable. The dimensions of key structures can be controlled within the nanometer to micrometer range, facilitating the design and fabrication of high-precision micro-nanostructures. Furthermore, the above-mentioned fabrication method has strong process compatibility and utilizes relatively mature semiconductor processes, facilitating integration with existing MEMS or integrated circuit manufacturing processes, improving production efficiency and reducing manufacturing costs. The material selection for key structures is highly flexible, allowing optimization based on different application environments, enhancing the adaptability and customizability of the device.

[0123] The single-pole double-throw switch formed based on the preparation method has a sandwich type vertical structure, and electrical isolation is achieved between the common input end IN, the first output end OUT1 and the second output end OUT2 based on vertical space, which is beneficial to optimizing the lead design by using the vertical space, reducing the plane area, and improving the integration, reliability and radio frequency performance of the micro electro-mechanical radio frequency switch in a high frequency system.

[0124] Through the preparation method, the two driving electrodes, the signal line and the output end of the single-pole double-throw switch are reasonably arranged on different layers to form a vertical stacked structure, which not only effectively saves the horizontal area of the chip, improves the structural strength and thermal stability, but also realizes better radio frequency performance matching on the basis of miniaturization.

[0125] In some embodiments, as shown in FIG. 1, the method further includes forming a first bump 15 on the first substrate 11 before forming the first contact 13. The first contact 13 is located on a side of the first bump 15 away from the first substrate 11 after forming the first contact 13. The method further includes forming a second bump 25 on the second substrate 21 before forming the second contact 23. The second contact 23 is located on a side of the second bump 25 away from the second substrate 21 after forming the second contact 23. Figure 5

[0126] For example, the materials of the first bump 15 and the second bump 25 are both silicon nitride. Silicon nitride thin films are deposited on silicon wafers by chemical vapor deposition or physical vapor deposition, and then patterned by photolithography and dry etching techniques to remove the excess part. Taking the first bump 15 as an example, in combination with the size design of the single-pole double-throw switch described above, the thickness of the first bump 15 ranges from 10 nm to 10 μm, and the length of the first bump 15 ranges from 100 nm to 10 μm in the on direction of the switch. The first bump 15 provides a basis for the subsequent preparation of the first contact 13, reduces the distance between the first contact 13 and the suspended electrode 30, and thus improves the performance of the single-pole double-throw switch.

[0127] The above merely provides a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can make changes or substitutions within the technical scope disclosed in the present application, which shall be covered by the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.​

Claims

1. A radio frequency MEMS single-pole double-throw switch, characterized in that: comprising a first layer structure, a suspended electrode and a second layer structure which are stacked; The first layer structure includes a first substrate, a first driving electrode and a first contact, wherein the first driving electrode and the first contact are both arranged on a side of the first substrate close to the second layer structure; The second layer structure includes a second substrate, a second driving electrode and a second contact, wherein the second driving electrode and the second contact are both arranged on a side of the second substrate close to the first layer structure; The suspended electrode is arranged between the first layer structure and the second layer structure, and the single-pole double-throw switch also includes a common input terminal, and the suspended electrode is connected to the common input terminal; the suspended electrode is configured to contact the first contact under the drive of the first driving electrode, and to contact the second contact under the drive of the second driving electrode.

2. The single-pole double-throw switch according to claim 1, characterized in that: The common input terminal includes a first signal line, the first signal line is arranged on a side of the first substrate close to the second layer structure, and the suspended electrode is electrically connected to the first signal line; and / or, The common input end includes a second signal line, the second signal line is arranged on a side of the second substrate close to the first layer structure, and the suspended electrode is electrically connected to the second signal line.

3. The single-pole double-throw switch according to claim 2, characterized in that: In the case where the common input terminal includes a first signal line, the first driving electrode is located between the first signal line and the first contact along a direction parallel to the first substrate; or the first contact is located between the first signal line and the first driving electrode; and / or, When the common input terminal includes a second signal line, the second driving electrode is located between the second signal line and the second contact along a direction parallel to the second substrate; or the second contact is located between the second signal line and the second driving electrode.

4. The single-pole double-throw switch according to claim 2, characterized in that: The single-pole double-throw switch further includes an anchor point, wherein the anchor point is arranged between the first layer structure and the second layer structure; In the case where the common input terminal includes a first signal line, the suspended electrode is electrically connected to the first signal line via the anchor point; and / or, In a case where the common input terminal includes a second signal line, the suspended electrode is electrically connected to the second signal line through the anchor point.

5. The single-pole double-throw switch according to claim 4, characterized in that: The anchor point includes a first sub-anchor point and a second sub-anchor point; The first sub-anchor point is arranged between the suspended electrode and the first signal line, and the suspended electrode and the first sub-anchor point are arranged integrally; the second sub-anchor point is arranged between the suspended electrode and the second signal line, and the suspended electrode and the second sub-anchor point are bonded to each other.

6. The single-pole double-throw switch according to claim 1, wherein: The first layer structure further includes a first bump, wherein the first bump is disposed between the first substrate and the first contact; The second layer structure further includes a second bump, and the second bump is arranged between the second substrate and the second contact.

7. A method for preparing a single-pole double-throw switch, characterized in that: include: forming a first driving electrode and a first contact on a first substrate to form a first layer structure; and forming a second driving electrode and a second contact on the second substrate to form a second layer structure; forming a suspended electrode on the first layer structure; Disposing the second layer structure on a side of the suspended electrode away from the first layer structure; The single-pole double-throw switch further includes a common input terminal, and the suspended electrode is connected to the common input terminal; the suspended electrode is configured to contact the first contact under the drive of the first driving electrode, and to contact the second contact under the drive of the second driving electrode.

8. The preparation method according to claim 7, characterized in that The forming of the first layer structure comprises: forming a first driving electrode on the first substrate; forming a first isolation layer on the first driving electrode; forming a first signal line and the first contact, wherein the first driving electrode is located between the first signal line and the first contact in a direction parallel to the first substrate; or, the first contact is located between the first signal line and the first driving electrode; The forming of the second layer structure comprises: forming a second driving electrode on the second substrate; forming a second isolation layer on the second driving electrode; A second signal line and the second contact are formed, and along a direction parallel to the second substrate, the second driving electrode is located between the second signal line and the second contact; or the second contact is located between the second signal line and the second driving electrode.

9. The preparation method according to claim 7, characterized in that Forming a suspended electrode on the first layer structure, comprising: forming a sacrificial layer on the first layer structure, wherein the sacrificial layer includes a through hole extending therethrough; forming a first sub-anchor point in the through hole, and forming an electrode on the sacrificial layer, wherein the electrode and the first sub-anchor point are integrally provided; removing the sacrificial layer to form a suspended electrode; Before disposing the second layer structure on a side of the suspended electrode away from the first layer structure, the method further includes: forming a second sub-anchor point on the second layer structure; Disposing the second layer structure on a side of the suspended electrode away from the first layer structure includes: bonding the second layer structure to the side of the suspended electrode away from the first layer structure through the second sub-anchor point.

10. The preparation method according to claim 7, characterized in that Before forming the first contact, the method further includes: forming a first bump on the first substrate; After forming the first contact, the first contact is located on a side of the first bump away from the first substrate; Before forming the second contact, the method further includes: forming a second bump on the second substrate; After the second contact is formed, the second contact is located on a side of the second bump away from the second substrate.

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