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 performance improvement. 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 purpose, the embodiments of the present application provide the following technical solutions: In a first aspect, a single-pole double-throw switch of a radio frequency MEMS is provided, which includes a first layer structure, a suspended electrode, and a second layer structure arranged in a stack.

[0006] The first layer structure includes 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 of the first substrate close to the second layer structure.

[0007] The second layer structure includes 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 of the second substrate close to the first layer structure.

[0008] 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 driving electrode, and in contact with the second contact under the driving of the second driving electrode.

[0009] In some embodiments, the common input terminal includes a first signal line arranged on the side of the first substrate close to the second layer structure, and the suspended electrode is electrically connected to the first signal line.

[0010] And / or, the common input terminal includes a second signal line, which is disposed on the side of the second substrate near the first layer structure, and the floating electrode is electrically connected to the second signal line.

[0011] In some embodiments, when the common input terminal includes a 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.

[0012] And / or, if the common input terminal includes a 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.

[0013] In some embodiments, the single-pole double-throw switch further includes an anchor point disposed between the first layer structure and the second layer structure.

[0014] When the common input terminal includes a first signal line, the floating electrode is electrically connected to the first signal line via an anchor point.

[0015] And / or, if the common input terminal includes a second signal line, the floating electrode is electrically connected to the second signal line via an anchor point.

[0016] In some embodiments, the anchor point includes a first sub-anchor point and a second sub-anchor point. The first sub-anchor point is disposed between the suspended electrode and the first signal line, and the suspended electrode and the first sub-anchor point are integrally disposed thereon. The second sub-anchor point is disposed between the suspended electrode and the second signal line, and the suspended electrode and the second sub-anchor point are bonded together.

[0017] In some embodiments, the first layer structure further includes a first bump disposed between the first substrate and the first contact. The second layer structure further includes a second bump disposed between the second substrate and the second contact.

[0018] Secondly, a method for preparing a single-pole double-throw switch is also provided, comprising the following steps S10 to S30: Step S10: A first driving electrode and a first contact are formed on a first substrate to form a first layer structure, and a second driving electrode and a second contact are formed on a second substrate to form a second layer structure.

[0019] Step S20: Form a suspended electrode on the first layer structure.

[0020] Step S30: Place the second layer structure on the side of the suspended electrode away from the first layer structure.

[0021] The single-pole double-throw switch also includes a common input terminal, to which a floating electrode is connected. The floating electrode is configured to contact the first contact under the drive of the first drive electrode, and to contact the second contact under the drive of the second drive electrode.

[0022] In some embodiments, forming a first layer structure includes steps S111 to S113: Step S111: Form a first driving electrode on the first substrate.

[0023] Step S112: Form a first isolation layer on the first driving electrode.

[0024] Step S113: Form a first signal line and a first contact point. Along a direction parallel to the first substrate, the first driving electrode is located between the first signal line and the first contact point, or the first contact point is located between the first signal line and the first driving electrode.

[0025] The formation of the second layer structure includes steps S121 to S123: Step S121: Form a second driving electrode on the second substrate.

[0026] Step S122: Form a second isolation layer on the second driving electrode.

[0027] Step S123: Form a second signal line and a second contact. 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.

[0028] In some embodiments, forming a suspended electrode on the first layer structure includes steps S21 to S23: Step S21: A sacrificial layer is formed on the first layer structure, the sacrificial layer including through-holes.

[0029] Step S22: Form a first sub-anchor point in the through hole and form an electrode on the sacrificial layer. The electrode and the first sub-anchor point are integrally set.

[0030] Step S23: Remove the sacrificial layer to form a suspended electrode.

[0031] Before placing the second layer structure on the 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.

[0032] The second layer structure is positioned on the side of the suspended electrode away from the first layer structure, including: bonding the second layer structure to the side of the suspended electrode away from the first layer structure via a second sub-anchor point.

[0033] In some embodiments, before forming the first contact, a first bump is formed on the first substrate. After forming the first contact, the first contact is located on the side of the first bump away from the first substrate.

[0034] Before forming the second contact, a second bump is formed on the second substrate. After forming the second contact, the second contact is located on the side of the second bump away from the second substrate.

[0035] In the embodiments provided in this application, a first layer structure, a floating electrode, and a second layer structure are stacked. The floating electrode is disposed between the first and second layer structures and connected to the common input terminal of the single-pole double-throw switch. The first contact in the first layer structure can serve as the first output terminal of the single-pole double-throw switch, and the second contact in the second layer structure can serve as the second output terminal of the single-pole double-throw switch. Under the drive of the first driving electrode, the floating electrode contacts the first contact, thereby achieving conduction between the common input terminal and the first output terminal. Under the drive of the second driving electrode, the floating electrode contacts the second contact, thereby achieving conduction between the common input terminal and the second output terminal. In this application, the single-pole double-throw switch forms a three-dimensional stacked structure, with the two output terminals arranged opposite each other in the vertical direction. This fully utilizes vertical space to optimize the structural layout, which is beneficial for electrode isolation and lead design, reduces the planar area, and improves the integration, reliability, and RF performance of the microelectromechanical RF switch in high-frequency systems.

[0036] The above preparation method is simple, easy to implement, and highly compatible with the process. It is beneficial to improve production efficiency, reduce manufacturing costs, and facilitate the design and manufacturing of high-precision micro-nano structures. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in some embodiments of this application will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not actual dimensions of the products or actual processes of the methods involved in the embodiments of this application.

[0038] Figure 1 The circuit symbol diagram for a single-pole double-throw switch; Figure 2 A schematic diagram of a single-pole double-throw switch provided in an embodiment of this application; Figure 3 A schematic diagram of another single-pole double-throw switch provided in this application embodiment; Figure 4 A flowchart illustrating a method for fabricating a single-pole double-throw switch, as provided in this application embodiment; Figures 5-14 for Figure 4 The diagram shows the steps of the preparation method. Detailed Implementation

[0039] The technical solutions in some embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application are within the scope of protection of this application.

[0040] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as open and encompassing, that is, "including, but not limited to".

[0041] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this application, unless otherwise stated, "a plurality of" means two or more.

[0042] In describing some embodiments, the term "connection" and its derivative expressions may be used. The term "connection" should be interpreted broadly; for example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium. For example, in describing some embodiments, the term "connection" may be used to indicate that two or more components have direct physical or electrical contact with each other.

[0043] In addition, the use of “based on” implies openness and inclusivity, because processes, steps, calculations or other actions “based on” one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0044] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on the other layer or substrate, or that there is an intermediate layer between the layer or element and the other layer or substrate.

[0045] This document describes exemplary embodiments with reference to cross-sectional views, which are intended as idealized exemplary drawings. In the drawings, the thickness of the layers and the area of ​​the regions are enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include shape deviations caused, for example, by manufacturing processes. For example, etched areas shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the areas of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0046] Currently, with the continuous advancement of information technology, modern communication systems are rapidly developing towards higher frequencies, higher bandwidths, and multi-functional integration. The rise of technologies such as 5G, millimeter-wave communication, radar systems, satellite navigation, reconfigurable antennas, and smart terminals has placed higher performance demands on radio frequency (RF) front-end devices. Among many key components, the radio frequency switch (RF switch), as a crucial component for signal selection, path switching, and channel control, directly impacts the efficiency, reliability, and power consumption of the entire communication system. Traditional RF switch technologies are primarily based on semiconductor processes, such as PIN diodes and CMOS field-effect transistors (FETs). While these switches offer advantages such as fast response speed, low drive voltage, and mature manufacturing processes, their high insertion loss, low isolation, poor linearity, and high power consumption at high frequencies severely restrict their further application in next-generation communication systems. Especially in the 10 GHz and above frequency bands, traditional switches can no longer meet the comprehensive requirements for low power consumption, low loss, and high isolation.

[0047] In recent years, microelectromechanical systems (MEMS)-based radio frequency (RF) switches have become an important research direction for high-performance RF switches due to their superior characteristics such as simple structure, extremely low power consumption, high operating frequency, low insertion loss, high isolation, and good linearity. Compared with traditional semiconductor switches, they exhibit better RF performance over a wide frequency band, making them an ideal choice for realizing high-performance, low-power, and highly integrated RF modules.

[0048] However, most existing RF MEMS switches are planar structures, primarily single-pole single-throw (SPST). This planar layout has significant limitations in integrating multiple ports, achieving high-density packaging, and miniaturization, making it difficult to fully utilize the three-dimensional spatial advantages of MEMS structures. Furthermore, due to the limited planar space, lead design, electrode isolation, drive response, and structural release processes within the confined space also restrict performance improvements.

[0049] Based on this, this application provides a single-pole double-throw switch for radio frequency MEMS, such as...Figures 1-3 As shown, Figure 1 The circuit symbol diagram for a single-pole double-throw switch is shown. Figure 2 This is a schematic diagram of a single-pole double-throw switch provided in an embodiment of this application. Figure 3 This is a schematic diagram of another single-pole double-throw switch provided in an embodiment of this application.

[0050] like Figure 1 As shown, a single-pole double-throw switch includes a common input terminal IN and two output terminals, which are denoted as the first output terminal OUT1 and the second output terminal OUT2, respectively.

[0051] like Figure 2 As shown, the single-pole double-throw switch includes a first layer structure 10, a floating electrode 30, and a second layer structure 20 stacked together. The floating electrode 30 is disposed between the first layer structure 10 and the second layer structure 20 and is connected to the common input terminal IN.

[0052] The first layer structure 10 includes a first substrate 11, a first driving electrode 12, and a first contact 13. The first driving electrode 12 and the first contact 13 are both disposed on the side of the first substrate 11 closer to the second layer structure 20, that is, the first contact 13 is disposed on the side closer to the floating electrode 30. Here, the first contact 13 can serve as the first output terminal OUT1 of a single-pole double-throw switch.

[0053] The suspended electrode 30 is configured to contact the first contact 13 under the drive of the first driving electrode 12. Exemplarily, the material of the first driving electrode 12 includes gold, aluminum, titanium, chromium, tungsten, molybdenum, or platinum. Applying a driving voltage to the first driving electrode 12 generates an electrostatic force between the suspended electrode 30 and the first driving electrode 12, the magnitude of which is related to the magnitude of the applied voltage. When the electrostatic force exceeds the elastic restoring force of the suspended electrode 30, the suspended electrode 30 bends towards 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.

[0054] That is, the first driving electrode 12 can drive the floating electrode 30 under nanosecond-level voltage loading, so that it contacts or disconnects from the first contact 13, thereby realizing the conduction or cutoff of the radio frequency signal of the first output terminal OUT1.

[0055] The second layer structure 20 includes a second substrate 21, a second driving electrode 22, and a second contact 23. Both the second driving electrode 22 and the second contact 23 are disposed on the side of the second substrate 21 closest to the first layer structure 10; that is, the second contact 23 is disposed on the side closest to the suspended electrode 30. Here, the second contact 23 can serve as the second output terminal OUT2 of a single-pole double-throw switch.

[0056] The suspended electrode 30 is also configured to contact the second contact 23 under the drive of the second driving electrode 22. Referring to the working principle described above, the material of the second driving electrode 22 may, for example, include gold, aluminum, titanium, chromium, tungsten, molybdenum, or platinum. Applying a driving voltage to the second driving electrode 22 generates an electrostatic force between the suspended electrode 30 and the second driving electrode 22, the magnitude of which is related to the magnitude of the applied voltage. When the electrostatic force exceeds 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 achieving conduction between the common input terminal IN and the second output terminal OUT2.

[0057] That is, the second driving electrode 22 can drive the floating electrode 30 under nanosecond-level voltage loading, so that it contacts or disconnects from the second contact 23, thereby realizing the conduction or cutoff of the radio frequency signal of the second output terminal OUT2.

[0058] In summary, in the embodiments of this application, the single-pole double-throw switch has a three-dimensional stacked structure, with two output terminals and a common input terminal forming a sandwich-type vertical structure. The two output terminals are arranged opposite each other in the vertical direction. The first driving electrode 12 and the second driving electrode 22 serve as the two control terminals of the single-pole double-throw switch, respectively. Under the action of electrostatic driving, the suspended electrode 30 is driven to bend upward or downward, thereby realizing the single-pole double-throw function.

[0059] In this application, the single-pole double-throw switch makes full use of vertical space to optimize the structural layout, which is conducive to achieving electrical isolation between the common input terminal IN, the first output terminal OUT1, and the second output terminal OUT2. It is also conducive to optimizing the lead design using vertical space, reducing the planar area, and improving the integration, reliability, and RF performance of the microelectromechanical RF switch in high-frequency systems.

[0060] In some embodiments, such as Figure 2 As shown, the common input terminal IN includes a first signal line 14, which is disposed on the side of the first substrate 11 near the second layer structure 20. The floating electrode 30 is electrically connected to the first signal line 14.

[0061] Alternatively, the common input terminal IN includes a second signal line 24, which is disposed on the side of the second substrate 21 near the first layer structure 10, and the floating electrode 30 is electrically connected to the second signal line 24.

[0062] Alternatively, the common input terminal IN includes both the first signal line 14 and the second signal line 24.

[0063] Either the first signal line 14 or the second signal line 24 can be used to achieve the electrical connection between the single-pole double-throw switch and the external circuit. That is, the input signal can be input to the single-pole double-throw switch through either 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 beneficial for the application of the single-pole double-throw switch in more complex circuit environments and for achieving multi-port integration and high-density packaging.

[0064] The first signal line 14 can be fabricated using the same process and materials as the first contact 13, and the second signal line 24 can be fabricated using the same process and materials as the second contact 23. For example, the materials of the first signal line 14 and the first contact 13, as well as the second signal line 24 and the second contact 23, all include gold, titanium, aluminum, or polycrystalline silicon. These materials all have good conductivity and can be selected and optimized according to different application environments to enhance the adaptability and customizability of the device.

[0065] In some embodiments, such as Figure 2 As shown, 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 along a direction parallel to the first substrate 11, or, as... Figure 3 As shown, the first contact 13 is located between the first signal line 14 and the first driving electrode 12.

[0066] It is understandable that the suspended electrode 30 includes a first end and a second end. Taking its first end being electrically connected to the common input terminal IN as an example, the statement that "the first driving electrode 12 is located between the first signal line 14 and the first contact 13" can be understood as follows: the electrostatic force provided by the first driving electrode 12 mainly acts on the middle part of the suspended electrode 30, causing the suspended electrode 30 to bend, thereby making the second end of the suspended electrode 30 electrically connected to the first contact 13. The first signal line 14 and the first contact 13 are located on both sides of the first driving electrode 12, which is beneficial for achieving electrical isolation between the first signal line 14 and the first contact 13 and avoiding short circuits. Compared to the middle part, the second end of the suspended electrode 30 has a larger bending range, making it easier to achieve electrical connection.

[0067] The statement that "the first contact 13 is located between the first signal line 14 and the first driving electrode 12" can be understood as follows: the electrostatic force provided by the first driving electrode 12 mainly acts on the second end of the suspended electrode 30, causing the suspended electrode 30 to bend, thereby making the middle part of the suspended electrode 30 electrically connected to the first contact 13. Based on this, under the same bending amplitude, the electrostatic force required in this embodiment is smaller, and the same bending amplitude can be achieved by applying a smaller voltage to the first driving electrode 12, which is beneficial to reducing power consumption.

[0068] Similarly, when the common input terminal includes the second signal line 24, such as Figure 2 As shown, along a direction parallel to the second substrate 21, the second driving electrode 22 is located between the second signal line 24 and the second contact 23. This facilitates electrical isolation between the second signal line 24 and the second contact 23, preventing short circuits. During operation, the electrostatic force provided by the second driving electrode 22 mainly acts on the middle part of the suspended electrode 30, causing 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, causing the suspended electrode 30 to bend, thereby making the middle part of the suspended electrode 30 electrically connected to the second contact 23. Applying a small voltage to the second driving electrode 22 can achieve the same bending amplitude, which is beneficial to reducing power consumption.

[0069] In some embodiments, such as Figures 2-3 As shown, the single-pole double-throw switch also includes an anchor point 40, which is located between the first layer structure 10 and the second layer structure 20.

[0070] Anchor point 40 serves to fix and support the structure, thereby realizing a sandwich-type vertical structure of the first layer structure 10, the suspended electrode 30, and the second layer structure 20. For example, the first end of the suspended electrode 30 is connected to anchor point 40, which is used to fix the suspended electrode 30 between the first layer structure 10 and the second layer structure 20, and to ensure that the middle part and the second end of the suspended electrode 30 are suspended.

[0071] Anchor point 40 is positioned between the first layer structure 10 and the second layer structure 20. During the bending process of the suspended electrode 30, the sandwich-type vertical structure further enhances the connection reliability of anchor point 40. For example, when the suspended electrode 30 bends towards the first contact 13, the second layer structure 20 improves the connection reliability between anchor point 40 and the first layer structure 10, preventing breakage and ensuring the reliability of the electrical connection between the suspended electrode 30 and the common input terminal IN. The same principle applies when the suspended electrode 30 bends towards the second contact 23, and will not be elaborated further here.

[0072] Anchor point 40 also has conductive properties. When the common input terminal includes the first signal line 14, the floating electrode 30 is electrically connected to the first signal line 14 through anchor point 40. When the common input terminal includes the second signal line 24, the floating electrode 30 is electrically connected to the second signal line 24 through anchor point 40.

[0073] For example, the anchor point 40 and the floating electrode 30 are made of the same material, including gold, titanium, aluminum, or polycrystalline silicon. These materials have good electrical conductivity. The external signal is electrically connected to the common input terminal IN and transmitted to the floating electrode 30 through the anchor point 40. In the on state, it is output through the output terminal. That is, the anchor point 40 can ensure the structural stability of the single-pole double-throw switch and also ensure a reliable electrical connection between the floating electrode 30 and the common input terminal IN, which is beneficial to ensuring the conduction performance of the switch.

[0074] In some embodiments, such as Figures 2-3 As shown, 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 together.

[0075] That is, the suspended electrode 30 is electrically connected to the first signal line 14 through the first sub-anchor point 41 and to the second signal line 24 through the second sub-anchor point 42. The suspended electrode 30 and the first sub-anchor point 41 are integrally formed, and the suspended electrode 30 and the second sub-anchor point 42 are bonded together. In other words, the suspended electrode 30 and the first sub-anchor point 41 can be prepared in the same process and using the same materials, and then bonded together with the second sub-anchor point 42. This not only simplifies the process and improves the feasibility of the process, but also improves the stability of the suspended electrode 30.

[0076] In some embodiments, such as Figures 2-3 As shown, the first layer structure 10 further includes a first bump 15, which is disposed between the first substrate 11 and the first contact 13. The second layer structure 20 further includes a second bump 25, which is disposed between the second substrate 21 and the second contact 23.

[0077] The first protrusion 15 reduces the distance between the first contact 13 and the floating electrode 30. Similarly, the second protrusion 25 reduces the distance between the second contact 23 and the floating electrode 30. With only a small bending deformation of the floating electrode 30, conduction between the common input terminal IN and the output terminal OUT can be achieved. Based on this, a small driving voltage can be applied to the first driving electrode 12 to achieve switch conduction, which helps reduce power consumption. Furthermore, the deformation of the floating electrode 30 is small during the switch from the off state to the on state, reducing the requirements for the bending performance of the floating electrode 30 and improving its service life.

[0078] Secondly, a method for preparing a single-pole double-throw switch is also provided, such as... Figure 4 As shown, Figure 4This is a flowchart illustrating a method for fabricating a single-pole double-throw switch according to an embodiment of this application. Figures 5-14 for Figure 4 The diagram shows the steps of the preparation method.

[0079] The preparation method includes the following steps S10 to S30: Step S10: As Figures 5-8 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.

[0080] For example, taking the first layer structure 10 as an example, the first substrate 11 is a silicon wafer with a thickness ranging from 100µm to 1000µm and a diameter ranging from 4 inches to 12 inches. The conductivity type of the silicon wafer can be N-type or P-type.

[0081] In some embodiments, forming the first layer structure 10 includes the following steps S111 to S113: Step S111: As Figures 5-6 As shown, a first driving electrode 12 is formed on the first substrate 11.

[0082] For example, a metal thin film is deposited on a silicon wafer using a thin film deposition technique (such as chemical vapor deposition or physical vapor deposition), and then the metal thin film is patterned using photolithography and etching techniques to finally form the first driving electrode 12.

[0083] The thickness of the metal thin film ranges from 10 nm to 10 µm. The materials of the metal thin film include gold, aluminum, titanium, chromium, tungsten, molybdenum or platinum. The etching technology includes dry etching or wet etching. After patterning along the conduction direction of the switch, the length of the first driving electrode 12 ranges from 100 nm to 10 µm.

[0084] Step S112: As Figure 7 As shown, a first isolation layer 16 is formed on the first driving electrode 12.

[0085] For example, a first isolation layer 16 is formed on the side of the first driving electrode 12 away from the first substrate 11 using low-pressure chemical vapor deposition, plasma-enhanced chemical vapor deposition, or atmospheric pressure chemical vapor deposition techniques. 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.

[0086] Step S113: As Figure 8 As shown, a first signal line 14 and a first contact 13 are formed.

[0087] For example, a photoresist mask is formed, and a conductive thin film is formed on the first isolation layer 16 using magnetron sputtering, electron beam evaporation, electroplating, or low-pressure chemical vapor deposition techniques. The thickness of the conductive thin film ranges from 10 nm to 10 µm, and the material of the conductive thin film includes gold, titanium, aluminum, or polycrystalline silicon. Then, excess portions on the conductive film are removed using photolithography and lift-off techniques, ultimately forming the separated first signal line 14 and first contact 13. Along the conduction direction of the switch, the length of the first contact 13 ranges from 100 nm to 10 µm.

[0088] Along a 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. Or refer to... Figure 3 As shown, the first contact 13 is located between the first signal line 14 and the first driving electrode 12.

[0089] Similarly, the second layer structure 20 is formed, including steps S121 to S123: Step S121: As Figures 5-6 As shown, a second driving electrode 22 is formed on the second substrate 21.

[0090] Step S122: As Figure 7 As shown, a second isolation layer 27 is formed on the second driving electrode 22.

[0091] Step S123: As Figure 8 As shown, a second signal line 24 and a second contact 23 are formed along a direction parallel to the second substrate 21. The second driving electrode 22 is located between the second signal line 24 and the second contact 23. Alternatively, see [link to documentation]. Figure 3 As shown, the second contact 23 is located between the second signal line 24 and the second driving electrode 22.

[0092] The preparation method of the second layer structure 20 is similar to that of the first layer structure 10. Each preparation step is the same as the preparation method of the first layer structure 10 described above, and will not be repeated here.

[0093] Step S20: As Figures 9-11 As shown, a suspended electrode 30 is formed on the first layer structure 10.

[0094] For example, forming a suspended electrode 30 on the first layer structure 10 includes the following steps S21 to S23: Step S21: As Figure 9 As shown, a sacrificial layer 17 is formed on the first layer structure 10, and the sacrificial layer 17 includes through holes.

[0095] For example, the sacrificial layer 17 is made of polyimide. Polyimide is spin-coated onto the first layer structure 10 and pre-cured. Then, through-holes are formed on the sacrificial layer 17 using photolithography and development techniques, exposing 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-holes along the conduction direction of the switch ranges from 100 nm to 10 µm.

[0096] Step S22: As Figure 10 As shown, a first sub-anchor point 41 is formed in the through hole, and an electrode 30 is formed on the sacrificial layer 17. The electrode 30 and the first sub-anchor point 41 are integrally disposed.

[0097] For example, photoresist is spin-coated and electrode patterns are formed using photolithography and development techniques. Then, conductive materials (such as gold, titanium, aluminum, or polysilicon) are grown in the via and on the sacrificial layer 17 using magnetron sputtering, electron beam evaporation, electroplating, or low-pressure chemical vapor deposition techniques. After the photoresist is stripped, the surface is polished using planarization techniques, and finally the first sub-anchor point 41 and the electrode 30 are formed, realizing the integrated setting of the electrode 30 and the first sub-anchor point 41, wherein the part located in the via is the first sub-anchor point 41.

[0098] That is, along the conduction direction of the switch, the length of the first sub-anchor point 41 is the same as the length of the through hole, ranging from 100nm to 10µm. The relatively long length of the first sub-anchor point 41 is beneficial to improving structural stability. The thickness of the first sub-anchor point 41 is the same as the thickness of the sacrificial layer 17, ranging from 10nm to 10µm. The height of the electrode ranges from 10nm to 10µm (it can be understood that the thickness of the conductive material grown at the through hole is at least 20nm). Along the conduction direction of the switch, the length of the electrode 30 ranges from 100nm to 100µm. The length of the electrode 30 must ensure that it can be subjected to the electrostatic force of the first driving electrode 12 and can reliably connect to the first contact 13 under the action of the electrostatic force.

[0099] Step S23: As Figure 11 As shown, the sacrificial layer 17 is removed to form the suspended electrode 30.

[0100] For example, by using dry etching or wet etching processes, the sacrificial layer 17 is released, so that one end of the electrode 30 is fixed to the first layer structure 10 through the first sub-anchor point 41, and the other end is suspended.

[0101] Step S30: As Figures 12-14 As shown, the second layer structure 20 is disposed on the side of the suspended electrode 30 away from the first layer structure 10.

[0102] The single-pole double-throw switch also includes a common input terminal IN, and a floating electrode 30 is connected to the common input terminal IN. The floating electrode 30 is configured to contact the first contact 13 under the drive of the first drive electrode 12, and to contact the second contact 23 under the drive of the second drive electrode 22.

[0103] For example, to achieve the final sandwich-type vertical structure, before the second layer structure 20 is placed on the side of the suspended electrode 30 away from the first layer structure 10, the method further includes forming a second sub-anchor point 42 on the second layer structure 20.

[0104] 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, which includes a second signal line 24.

[0105] Then as Figure 12 As shown, refer to Figure 10 The corresponding method involves forming a second sub-anchor point 42 within the through hole.

[0106] Then as Figure 13 As shown, refer to Figure 11 The corresponding method is to remove the sacrificial layer 27, and finally form the second sub-anchor point 42 on the second layer structure 20.

[0107] Finally, as Figure 14 As shown, the second layer structure 20 is disposed 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 thermo-press bonding, diffusion bonding, ultrasonic bonding or surface activation bonding.

[0108] This forms a three-dimensional stacked structure consisting of the first layer structure 10, the suspended electrode 30, and the second layer structure 20.

[0109] The aforementioned fabrication method is simple and easy to implement, with precise control over size and structure. The dimensions of key structures can be controlled within the nanometer to micrometer range, which is beneficial for the design and fabrication of high-precision micro / nano structures. Furthermore, the method exhibits strong process compatibility, employing relatively mature semiconductor processes that facilitate integration with existing MEMS or integrated circuit manufacturing processes, improving production efficiency and reducing manufacturing costs. The material selection for key structures offers high freedom, allowing for optimization based on different application environments, enhancing the adaptability and customizability of the devices.

[0110] The single-pole double-throw switch formed by the above preparation method has a sandwich-type vertical structure. Based on the vertical space, electrical isolation is achieved between the common input terminal IN, the first output terminal OUT1, and the second output terminal OUT2. This is beneficial for optimizing lead design by utilizing the vertical space, reducing the planar area, and improving the integration, reliability, and RF performance of the microelectromechanical RF switch in high-frequency systems.

[0111] Using the above-mentioned fabrication method, the two driving electrodes, signal lines, and output terminals of the single-pole double-throw switch are rationally arranged on different layers to form a vertical stacked structure. This not only effectively saves the lateral area of ​​the chip and improves the structural strength and thermal stability, but also achieves better RF performance matching on the basis of miniaturization.

[0112] In some embodiments, such as Figure 5 As shown, before forming the first contact 13, a first bump 15 is formed on the first substrate 11. After forming the first contact 13, the first contact 13 is located on the side of the first bump 15 away from the first substrate 11. Before forming the second contact 23, a second bump 25 is formed on the second substrate 21. After forming the second contact 23, the second contact 23 is located on the side of the second bump 25 away from the second substrate 21.

[0113] For example, both the first bump 15 and the second bump 25 are made of silicon nitride. A silicon nitride thin film is deposited on a silicon wafer using chemical vapor deposition or physical vapor deposition, followed by patterning and removal of excess material using photolithography and dry etching techniques. Taking the first bump 15 as an example, considering 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 along the conduction direction of the switch ranges from 100 nm to 10 µm. The configuration of the first bump 15 forms the basis for the subsequent fabrication of the first contact 13, reducing the distance between the first contact 13 and the floating electrode 30, thereby improving the performance of the single-pole double-throw switch.

[0114] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A single-pole double-throw switch for radio frequency MEMS, characterized in that, This includes a first layer structure stacked together, a suspended electrode, and a second layer structure. 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 disposed on the 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 disposed on the side of the second substrate close to the first layer structure; The suspended electrode is disposed between the first layer structure and the second layer structure. 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, which is disposed on the side of the first substrate near the second layer structure, and the floating electrode is electrically connected to the first signal line; and / or, The common input terminal includes a second signal line, which is disposed on the side of the second substrate near the first layer structure, and the floating electrode is electrically connected to the second signal line.

3. The single-pole double-throw switch according to claim 2, characterized in that, When the common input terminal includes a first signal line, the first driving electrode is located between the first signal line and the first contact point along a direction parallel to the first substrate; or, the first contact point 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 in 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 also includes an anchor point, which is disposed between the first layer structure and the second layer structure; When the common input terminal includes a first signal line, the floating electrode is electrically connected to the first signal line via the anchor point; and / or, When the common input terminal includes a second signal line, the floating 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 disposed between the suspended electrode and the first signal line, and the suspended electrode and the first sub-anchor point are integrally disposed thereon; the second sub-anchor point is disposed between the suspended electrode and the second signal line, and the suspended electrode and the second sub-anchor point are bonded together.

6. The single-pole double-throw switch according to claim 1, characterized in that, The first layer structure further includes a first bump, which is disposed between the first substrate and the first contact. The second layer structure also includes a second bump, which is disposed between the second substrate and the second contact.

7. A method for manufacturing a single-pole double-throw switch, characterized in that, include: A first driving electrode and a first contact are formed on a first substrate to form a first layer structure; A second driving electrode and a second contact are formed on the second substrate to form a second layer structure; A suspended electrode is formed on the first layer structure; The second layer structure is disposed on the 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 floating electrode is connected to the common input terminal; the floating 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 formation of the first layer structure includes: A first driving electrode is formed on the first substrate; A first isolation layer is formed on the first driving electrode; A first signal line and a first contact are formed along a direction parallel to the first substrate, and the first driving electrode is located between the first signal line and the first contact; or, the first contact is located between the first signal line and the first driving electrode. The formation of the second layer structure includes: A second driving electrode is formed on the second substrate; A second isolation layer is formed on the second driving electrode; A second signal line and a second contact are formed along a direction parallel to the second substrate, with the second driving electrode 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 includes: A sacrificial layer is formed on the first layer structure, the sacrificial layer including through-holes; A first sub-anchor point is formed within the through hole, and an electrode is formed on the sacrificial layer, wherein the electrode is integrally disposed with the first sub-anchor point; Remove the sacrificial layer to form a suspended electrode; Before placing the second layer structure on the 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; The second layer structure is disposed on the side of the suspended electrode away from the first layer structure, including: 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 the first contact point is formed, the first contact point is located on the 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 the side of the second bump away from the second substrate.

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