Micro-electro-mechanical system switch

Abstract

The present disclosure provides a micro-electro-mechanical system switch, comprising a substrate, a signal electrode arranged on the substrate, two reference electrodes arranged on both sides of the signal electrode, and a membrane bridge arranged on the side of the reference electrode away from the substrate and connected with at least one of the reference electrodes; wherein the membrane bridge comprises a first metal layer and at least one organic polymer layer, the elastic modulus of the organic polymer layer is less than the elastic modulus of the first metal layer; and the first metal layer is covered with the organic polymer layer on at least part of the surface on at least one of the two sides away from and close to the signal electrode.

Description

Microelectromechanical system switch Technical Field

[0001] This disclosure relates to the field of radio frequency switch technology, and more specifically, to a microelectromechanical system switch. Background Technology

[0002] MEMS (Micro-Electro-Mechanical Systems) switches are switching devices fabricated using MEMS technology. They control signal conduction and disconnection through the movement of micromechanical structures. MEMS switches are one of the core components of microwave and radio frequency transceiver systems, with wide applications in satellite communications, radar, missile control, and other fields. Compared with traditional PIN and FET switches, MEMS switches not only possess superior microwave performance such as high isolation, low loss, low insertion loss, and high linearity, but also feature easy mass production, small size, and easy integration with advanced microwave and radio frequency circuits. They are a key technology for realizing miniaturized, low-cost, and high-performance microwave transceiver front-end systems. Summary of the Invention

[0003] This disclosure aims to address at least one of the technical problems existing in the prior art, and proposes a microelectromechanical system switch.

[0004] To achieve the above objectives, this disclosure provides a microelectromechanical system (MEMS) switch, including a substrate, a signal electrode disposed on the substrate, two reference electrodes located on both sides of the signal electrode, and a membrane bridge disposed on the side of the reference electrode away from the substrate and connected to at least one of the reference electrodes; wherein the membrane bridge includes a first metal layer and at least one organic polymer layer, and the elastic modulus of the organic polymer layer is less than the elastic modulus of the first metal layer;

[0005] The first metal layer has at least a portion of its surface covered with the organic polymer layer on at least one side of the side facing away from and near the signal electrode.

[0006] In some embodiments, the organic polymer layer comprises a polyimide layer.

[0007] In some embodiments, the first metal layer includes a bridge body disposed on the side of the signal electrode opposite to the substrate, and at least one connecting arm for connecting one end of the bridge body to the reference electrode.

[0008] The bridge body has a first bridge surface and a second bridge surface, respectively, on the side close to and away from the signal electrode. The organic polymer layer on the side of the first metal layer close to the signal electrode covers at least a portion of the first bridge surface; the organic polymer layer on the side of the first metal layer away from the signal electrode covers at least a portion of the second bridge surface.

[0009] In some embodiments, each of the connecting arms has a first side and a second side respectively close to and away from the signal electrode; the first side intersects with the first bridge surface, and the second side intersects with the second bridge surface;

[0010] The organic polymer layer located on the side of the first metal layer near the signal electrode covers the intersection of the first side surface and the first bridge surface, as well as at least a portion of the first side surface and at least a portion of the first bridge surface located on both sides of the intersection line.

[0011] The organic polymer layer located on the side of the first metal layer opposite to the signal electrode covers the intersection of the second side surface and the second bridge surface, as well as at least a portion of the second side surface and at least a portion of the second bridge surface located on both sides of the intersection line.

[0012] In some embodiments, the orthographic projection of the portion of the organic polymer layer covering the first bridge surface on the substrate is offset from the orthographic projection of the signal electrode on the substrate.

[0013] In some embodiments, the orthographic projection of the portion of the organic polymer layer covering the second bridge surface on the substrate is offset from the orthographic projection of the signal electrode on the substrate.

[0014] In some embodiments, there are two connecting arms, namely a first connecting arm and a second connecting arm, and the two ends of the bridge body are respectively connected to the two reference electrodes through the first connecting arm and the second connecting arm;

[0015] The portion of the organic polymer layer covering the first bridge surface includes a first edge portion, a second edge portion, and at least one first support portion, wherein the first support portion is connected between the first edge portion and the second edge portion.

[0016] In some embodiments, there are two connecting arms, namely a first connecting arm and a second connecting arm, and the two ends of the bridge body are respectively connected to the two reference electrodes through the first connecting arm and the second connecting arm;

[0017] The portion of the organic polymer layer covering the second bridge surface includes a third edge portion, a fourth edge portion, and at least one second support portion, the second support portion being connected between the third edge portion and the fourth edge portion.

[0018] In some embodiments, the organic polymer layer located on the side of the first metal layer near the signal electrode also covers at least a portion of the side of the reference electrode near the signal electrode.

[0019] In some embodiments, the membrane bridge further includes an adhesion layer located between the first metal layer and the organic polymer layer.

[0020] In some embodiments, the adhesion layer comprises a nitride layer or an oxide layer.

[0021] In some embodiments, the thickness of the adhesion layer is greater than or equal to 0.1 μm and less than or equal to 0.3 μm.

[0022] In some embodiments, the membrane bridge further includes a protective layer covering at least a portion of the surface of the organic polymer layer on the side opposite to the first metal layer.

[0023] In some embodiments, the protective layer comprises a nitride layer or an oxide layer.

[0024] In some embodiments, the organic polymer layer is provided with at least one through-hole extending along its thickness.

[0025] In some embodiments, the through hole is a circular hole with a diameter greater than or equal to 5 μm and less than or equal to 20 μm.

[0026] In some embodiments, the membrane bridge further includes a second metal layer covering the surface of the organic polymer opposite to the first metal layer and connected to the first metal layer through each of the through-holes.

[0027] In some embodiments, the thickness of the first metal layer is greater than or equal to 1 μm and less than or equal to 3 μm.

[0028] In some embodiments, the thickness of the organic polymer layer located on the side of the first metal layer near the signal electrode is greater than or equal to 0.5 μm and less than or equal to 2 μm.

[0029] In some embodiments, the thickness of the organic polymer layer located on the side of the first metal layer opposite to the signal electrode is greater than or equal to 1 μm and less than or equal to 20 μm. Attached Figure Description

[0030] Figure 1 is a top view of a first type of microelectromechanical system switch provided in an embodiment of this disclosure;

[0031] Figure 2 is a cross-sectional view along line A-A' in Figure 1;

[0032] Figure 3 is a cross-sectional view of a second type of microelectromechanical system switch provided in an embodiment of this disclosure;

[0033] Figure 4 is a cross-sectional view of a third type of microelectromechanical system switch provided in an embodiment of this disclosure;

[0034] Figure 5 is a cross-sectional view of the first metal layer used in the embodiment of this disclosure;

[0035] Figure 6 is a cross-sectional view of the organic polymer layer covering the bridge body used in the embodiments of this disclosure;

[0036] Figure 7 is a cross-sectional view of the fourth type of microelectromechanical system switch provided in the embodiments of this disclosure;

[0037] Figure 8 is a cross-sectional view of the fifth type of microelectromechanical system switch provided in the embodiments of this disclosure;

[0038] Figure 9 is a cross-sectional view of the sixth type of microelectromechanical system switch provided in the embodiments of this disclosure;

[0039] Figure 10 is a schematic diagram of the structure of the second organic polymer layer projected along the upward direction in Figure 9;

[0040] Figure 11 is a cross-sectional view of the seventh type of microelectromechanical system switch provided in the embodiments of this disclosure;

[0041] Figure 12 is a cross-sectional view of the eighth type of microelectromechanical system switch provided in the embodiments of this disclosure;

[0042] Figure 13 is a cross-sectional view of the ninth type of microelectromechanical system switch provided in the embodiments of this disclosure;

[0043] Figure 14 is a cross-sectional view of the tenth type of microelectromechanical system switch provided in the embodiments of this disclosure. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this disclosure clearer, the disclosure will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0045] The shapes and sizes of the components in the accompanying drawings do not reflect actual proportions and are intended only to facilitate understanding of the contents of the embodiments disclosed herein.

[0046] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “including,” “comprising,” or “containing,” and similar terms mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. The terms “connected,” “linked,” or similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0047] This disclosure is not limited to the embodiments shown in the accompanying drawings, but includes modifications to the configuration based on the manufacturing process. Therefore, the areas illustrated in the drawings are schematic, and the shapes of the areas shown illustrate specific shapes of the areas of an element, but are not intended to be limiting.

[0048] This disclosure provides a microelectro-mechanical system (MEMS) switch. The MEMS switch of this disclosure can be a radio frequency (RF) switch, which can be used in RF circuits to control the conduction or switching of signals. The MEMS switch of this disclosure is, for example, an RF switch based on a coplanar waveguide (CPW). Referring to Figures 1 and 2, the MEMS switch includes a substrate 1, a signal electrode 2 disposed on the substrate 1, two reference electrodes spaced apart on both sides of the signal electrode 2, and a membrane bridge 5 connected to at least one reference electrode. Specifically, the two reference electrodes are a first reference electrode 3 and a second reference electrode 4, both of which are grounded. The first reference electrode 3 and the second reference electrode 4 are located on both sides of the signal electrode 2, and are disposed opposite each other along a direction perpendicular to the extension direction of the signal electrode 2, and are disposed in the same layer as the signal electrode 2. The signal electrode 2, the first reference electrode 3, and the second reference electrode 4 form a coplanar waveguide (CPW) transmission line.

[0049] In some embodiments, the microelectromechanical system switch further includes an interlayer dielectric layer 6 that covers at least the side of the signal electrode 2 facing away from the substrate 1, thereby isolating the signal electrode 2 from other electrodes. For example, as shown in FIG2, the interlayer dielectric layer 6 may cover the surface of the signal electrode 2 facing away from the substrate 1 and the two sides intersecting with that surface. The material of the interlayer dielectric layer 6 includes, for example, silicon dioxide (SiO2) or silicon nitride (SiN). x )etc.

[0050] A membrane bridge 5 is disposed on the side of the first reference electrode 3 and the second reference electrode 4 facing away from the substrate 1. The extension direction of the membrane bridge 5 intersects the extension direction of the signal electrode 2, and the orthographic projection of the membrane bridge 5 on the substrate 1 partially overlaps with the orthographic projection of the signal electrode 2 on the substrate 1. The signal electrode 2 and the membrane bridge 5 are insulated from each other by an interlayer dielectric layer 6. The membrane bridge 5 serves as the upper electrode, and the signal electrode 2 serves as the lower electrode. Applying a driving voltage between the membrane bridge 5 and the signal electrode 2 enables a switching action. When the driving voltage is applied, the membrane bridge 5 moves under the influence of electrostatic force. When the membrane bridge 5 contacts the interlayer dielectric layer 6, the signal is interrupted. When the driving voltage is removed, the membrane bridge 5 returns to its initial position, enabling the signal to be turned on.

[0051] Currently, membrane bridges are typically made of precious metals (such as Au). To address the issues of low lifespan and susceptibility to collapse, the thickness of the metal membrane bridge is increased to improve its stiffness and strength. However, this significantly increases the force required to pull the bridge down, directly leading to a substantial increase in driving voltage and response time, while also increasing cost. Improving response time requires a higher driving voltage or reducing the distance between the membrane bridge and the signal electrodes, but this reduces the radio frequency (RF) response range. Therefore, current membrane bridges cannot simultaneously meet the requirements for membrane bridge lifespan, response time, driving voltage, RF response range, and cost.

[0052] To address the aforementioned issues, in this embodiment of the present disclosure, as shown in FIG2, the membrane bridge 5 includes a first metal layer 51 and at least one organic polymer layer 52, wherein the elastic modulus of the organic polymer layer 52 is less than that of the first metal layer 51; and, at least a portion of the surface of the first metal layer 51 on at least one side (away from and near the signal electrode 2) is covered with the organic polymer layer 52. In one example, the organic polymer layer 52 in FIG2 is a single layer that covers the surface of the first metal layer 51 on the side away from the signal electrode 2, and is hereinafter referred to as the first organic polymer layer. In this case, the thickness of the first organic polymer layer can be a relatively large value to effectively improve the stiffness and strength of the membrane bridge; this thickness range is, for example, greater than or equal to 1 μm and less than or equal to 20 μm. Preferably, it is greater than 2 μm. In another example, as shown in FIG3, the organic polymer layer 52 in FIG3 is a single layer that covers the surface of the first metal layer 51 on the side near the signal electrode 2, and is hereinafter referred to as the second organic polymer layer. In this case, the thickness of the second organic polymer layer should not be too large to ensure that the distance between the membrane bridge 5 and the signal electrode 2 meets the requirements. This distance is, for example, not less than 0.6 μm, and preferably in the range of greater than 0.6 μm and less than 1.5 μm. Based on this, the thickness of the second organic polymer layer is, for example, greater than or equal to 0.5 μm and less than or equal to 2 μm. In another example, as shown in FIG4, the organic polymer layer 52 in FIG4 is a two-layer structure, which covers the surfaces of the first metal layer 51 on the sides near and away from the signal electrode 2, respectively. That is, a first organic polymer layer and a second organic polymer layer are provided simultaneously.

[0053] By employing a composite membrane layer comprising an organic polymer layer 52 and a first metal layer 51, where the elastic modulus of the organic polymer layer 52 is less than that of the first metal layer 51, the stiffness and strength of the membrane bridge 5 can be increased, making the membrane bridge 5 less prone to collapse, thereby improving the lifespan and reliability of the membrane bridge 5. Simultaneously, compared to directly increasing the thickness of the metal membrane bridge 5 to improve lifespan, the thinner first metal layer 51 used in this embodiment makes the composite membrane layer comprising the organic polymer layer 52 and the first metal layer 51 more sensitive to applied forces, exhibiting better responsiveness. It also enhances deflection, sensitivity, and electromagnetic force induction. Therefore, while improving the lifespan and reliability of the membrane bridge 5, it avoids a significant increase in driving voltage and excessively long response time, making it easier to obtain a membrane bridge 5 with a longer lifespan, shorter response time, and lower driving voltage.

[0054] In some preferred embodiments, the organic polymer layer 52 includes a polyimide (PI) layer. The polyimide layer can withstand nearly one million high-amplitude bending cycles and up to 10⁹ micro-vibrations, effectively improving the membrane bridge lifespan. In contrast, a 2 μm thick Au film layer only withstands 10⁵ micro-vibrations, resulting in a significantly lower lifespan. Furthermore, the polyimide layer exhibits excellent acid and alkali chemical stability, resistance to temperatures above 400°C, no distinct melting point, high insulation, and excellent mechanical properties, making it compatible with high-sensitivity semiconductor processes involving high temperatures.

[0055] Furthermore, although the Au film layer with a thickness of 6 μm can also achieve 109 micro-vibrations, its lifespan is comparable to that of the composite film layer in this disclosure embodiment. However, due to its thicker metal layer, as mentioned above, there is a conflict between lifespan and requirements such as response time and driving voltage. This disclosure embodiment combines the polyimide layer with the first metal layer 51, without increasing the thickness of the first metal layer 51. It utilizes an organic polymer layer 52 with a lower elastic modulus to increase the stiffness and strength of the membrane bridge 5, making the membrane bridge 5 less prone to collapse. This allows for improved lifespan and reliability of the membrane bridge 5 while using a thinner metal layer, thereby resolving the conflict between lifespan and requirements such as response time and driving voltage, resulting in a membrane bridge 5 with a longer lifespan, shorter response time, and lower driving voltage.

[0056] It should be noted that, in practical applications, the organic polymer layer 52 can also be made of other organic materials that achieve the above-mentioned functions and effects, and there are no particular limitations on this in the embodiments disclosed herein.

[0057] In some embodiments, referring to FIG5, the first metal layer 51 includes a bridge body 511 disposed on the side of the signal electrode 2 away from the substrate 1, and at least one connecting arm 512 for connecting one end of the bridge body 511 to a reference electrode. Specifically, the bridge body 511 is disposed on the side of the signal electrode 2 away from the substrate 1, the extending direction of the bridge body 511 intersects the extending direction of the signal electrode 2, and the orthographic projection of the bridge body 511 on the substrate 1 partially overlaps with the orthographic projection of the signal electrode 2 on the substrate 1.

[0058] The microelectromechanical system (MEMS) switch of this disclosure can be applied to both fixed-beam capacitor-type and cantilever beam contact-type RF switches. For the fixed-beam capacitor-type RF switch, as shown in Figures 2 to 4 and in conjunction with Figure 5, both ends of the bridge body 511 are connected to the first reference electrode 3 and the second reference electrode 4 respectively via two connecting arms 512. In some embodiments, as shown in Figures 5 and 6, each of the two connecting arms 512 has a connecting portion 513 at the end furthest from the bridge body 511. The connecting portions 513 of the two connecting arms 512 respectively cover the anchor areas of the first reference electrode 3 and the second reference electrode 4, used to connect the connecting arm 512 to the corresponding reference electrode. For the cantilever beam contact-type RF switch, one end of the bridge body 511 is connected to one of the first reference electrode 3 and the second reference electrode 4 via a connecting arm 512. The other end of the bridge body 511 is in contact with one of the first reference electrode 3 and the second reference electrode 4 when a driving voltage is applied, and separates after the driving voltage is removed. The above two types of MEMS switches are conventional technologies in the art and will not be described in detail here.

[0059] In some embodiments, as shown in FIG5, the bridge body 511 has a first bridge surface 511a and a second bridge surface 511b respectively on the side close to and away from the signal electrode 2. An organic polymer layer 52 (i.e., the second organic polymer layer) located on the side of the first metal layer 51 close to the signal electrode 2 covers at least a portion of the first bridge surface 511a; an organic polymer layer 52 (i.e., the first organic polymer layer) located on the side of the first metal layer 51 away from the signal electrode 2 covers at least a portion of the second bridge surface 511b. That is, the second organic polymer layer may cover the entire first bridge surface 511a or only a portion of it; the first organic polymer layer 52 may cover the entire second bridge surface 511b or only a portion of it. For example, FIG6 shows the first organic polymer layer covering the entire second bridge surface 511b. This can increase the stiffness and strength of the membrane bridge 5 to a certain extent, making it less prone to collapse. However, since the intersection of the bridge body 511 and each connecting arm 512 is a location where stress is relatively concentrated, the effect of simply covering the bridge surface to increase the stiffness and strength of the membrane bridge 5 is still limited.

[0060] To improve the above-mentioned problems, in some embodiments, as shown in FIG5, each connecting arm 512 has a first side surface 512a and a second side surface 512b respectively close to and away from the signal electrode 2, wherein the first side surface 512a intersects with the first bridge surface 511a, and the two are perpendicular to each other, for example. The second side surface 512b intersects with the second bridge surface 511b, and the two are perpendicular to each other, for example. Based on this, as shown in FIG3 and FIG4, and in conjunction with FIG5, for the organic polymer layer 52 (i.e., the second organic polymer layer) located on the side of the first metal layer 51 close to the signal electrode 2, it covers the intersection line of the first side surface 512a and the first bridge surface 511a and at least a portion of the first side surface 512a and at least a portion of the first bridge surface 511a located on both sides of the intersection line. That is, the second organic polymer layer can cover the entire first side surface 512a and the entire first bridge surface 511a, or the second organic polymer layer can also cover a portion of the first side surface 512a and a portion of the first bridge surface 511a located on both sides of the intersection line. Similarly, for the organic polymer layer 52 (i.e., the first organic polymer layer) located on the side of the first metal layer 51 away from the signal electrode 2, it covers the intersection of the second side surface 512b and the second bridge surface 511b, as well as at least a portion of the second side surface 512b and at least a portion of the second bridge surface 511b located on both sides of the intersection. That is, the first organic polymer layer can cover the entire second side surface 512b and the entire second bridge surface 511b, or it can cover a portion of the second side surface 512b and a portion of the second bridge surface 511b located on both sides of the intersection.

[0061] The intersection of the bridge body 511 and each connecting arm 512 is a location where stress is relatively concentrated. By ensuring that the organic polymer layer 52 at least covers the intersection of the bridge body 511 and each connecting arm 512, the stiffness and strength of the membrane bridge 5 can be effectively increased, making the membrane bridge 5 less prone to collapse, thereby improving the lifespan and reliability of the membrane bridge 5. Furthermore, in embodiments where the organic polymer layer 52 covers a portion of the bridge surface of the bridge body 511, it is equivalent to the organic polymer layer 52 having a cutout portion that exposes the bridge body 511. This cutout portion helps to mitigate the influence of the organic polymer layer 52 on the device capacitance and electric field. Preferably, the orthogonal projection of this cutout portion on the substrate 1 at least covers the orthogonal projection of the signal electrode 2 on the substrate 1.

[0062] In one example, to mitigate the impact of the organic polymer layer 52 on the device capacitance and electric field, the orthographic projection of the portion of the organic polymer layer 52 (i.e., the second organic polymer layer) covering the first bridge surface 511a on the substrate 1 is offset from the orthographic projection of the signal electrode 2 on the substrate 1. That is, the orthographic projection of the portion of the second organic polymer layer covering the first bridge surface 511a on the substrate 1 is outside the orthographic projection of the signal electrode 2 on the substrate 1, and there is no overlap. For example, as shown in FIG7, taking the microelectromechanical system switch of this embodiment of the present disclosure applied to a fixed-beam capacitor-type RF switch as an example, there are two connecting arms 512, namely the first connecting arm 5121 and the second connecting arm 5122. The two ends of the bridge body 511 are connected to two reference electrodes (i.e., the first reference electrode 3 and the second reference electrode 4) through the first connecting arm 5121 and the second connecting arm 5122, respectively. In this configuration, the portion of the second organic polymer layer covering the first bridge surface 511a includes, for example, a first edge portion 521a and a second edge portion 521b, which respectively cover two edge regions of the first bridge surface 511a. These two edge regions are adjacent to the first side surfaces 512a of the first connecting arms 5121 and 5122, respectively, and the orthographic projection of each edge region onto the substrate 1 does not coincide with the orthographic projection of the signal electrode 2 onto the substrate 1. The interval between the first edge portion 521a and the second edge portion 521b constitutes the aforementioned hollow portion of the second organic polymer layer.

[0063] Similarly, to mitigate the impact of the organic polymer layer 52 on the device capacitance and electric field, the orthographic projection of the portion of the organic polymer layer 52 (i.e., the first organic polymer layer) covering the second bridge surface 511b on the substrate 1 is offset from the orthographic projection of the signal electrode 2 on the substrate 1. That is, the orthographic projection of the portion of the first organic polymer layer covering the second bridge surface 511b on the substrate 1 is outside the orthographic projection of the signal electrode 2 on the substrate 1, and they do not overlap. For example, as shown in FIG8, the portion of the first organic polymer layer covering the second bridge surface 511b includes, for instance, a third edge portion 524a and a fourth edge portion 524b, which respectively cover two edge regions of the second bridge surface 511b. These two edge regions are adjacent to the second side surfaces 512b of the first connecting arm 5121 and the second connecting arm 5122, respectively, and the orthographic projection of each edge region on the substrate 1 does not overlap with the orthographic projection of the signal electrode 2 on the substrate 1. The gap between the third edge portion 524a and the fourth edge portion 524b constitutes the aforementioned hollow portion of the first organic polymer layer.

[0064] Additionally, referring to Figure 9, the distance between the orthographic projection of the portion of the second organic polymer layer covering the first bridge surface 511a onto the substrate 1 and the orthographic projection of the signal electrode 2 onto the substrate 1 is the first distance D1, and the distance between the orthographic projection of the portion of the first organic polymer layer covering the second bridge surface 511b onto the substrate 1 and the orthographic projection of the signal electrode 2 onto the substrate 1 is the second distance D2. The first distance D1 is different from the second distance D3. Specifically, the first distance D1 can be greater than the second distance D2, or the first distance D1 can be less than the second distance D2. Of course, in practical applications, depending on specific needs, the first distance D1 can also be equal to the second distance D2.

[0065] Furthermore, in embodiments where the portion of the second organic polymer layer covering the first bridge surface 511a includes a first edge portion 521a and a second edge portion 521b, as shown in FIG10, which is a schematic diagram of the structure of the second organic polymer layer projected in FIG9 from a bottom view direction, the second organic polymer layer, in addition to including the first edge portion 521a and the second edge portion 521b, also includes, for example, at least one first support portion 521c. The first support portion 521c connects between the first edge portion 521a and the second edge portion 521b, serving as a support between them, thereby further improving the stiffness and strength of the second organic polymer layer. Furthermore, in some embodiments, there are multiple first support portions 521c, spaced apart along the extension direction of the signal electrode 2.

[0066] Similarly, in embodiments where the portion of the first organic polymer layer covering the second bridge surface 511b includes a third edge portion 524a and a fourth edge portion 524b, the portion of the first organic polymer layer covering the second bridge surface 511b, in addition to including the third edge portion 524a and the fourth edge portion 524b, also includes, for example, at least one second support portion. The structure of this second support portion is similar to that of the first support portion 521c in FIG. 10, i.e., it connects between the third edge portion 524a and the fourth edge portion 524b, serving as a support between them, thereby improving the stiffness and strength of the first organic polymer layer. Further, in some embodiments, there are multiple second support portions, spaced apart along the extension direction of the signal electrode 2.

[0067] It should be noted that, in practical applications, the second organic polymer layer may cover a portion of the first bridge deck 511a (e.g., at least its edge area), and the first organic polymer layer may cover the entire second bridge deck 511b; or the second organic polymer layer may cover the entire first bridge deck 511a, and the first organic polymer layer may cover a portion of the second bridge deck 511b (e.g., at least its edge area); or the second organic polymer layer may cover a portion of the first bridge deck 511a (e.g., at least its edge area), and the first organic polymer layer may cover a portion of the second bridge deck 511b (e.g., at least its edge area); or the second organic polymer layer may cover the entire first bridge deck 511a, and the first organic polymer layer may cover the entire second bridge deck 511b. The above covering method can be selected according to specific needs.

[0068] In some embodiments, to further increase the stiffness and strength of the membrane bridge 5 and make it less prone to collapse, as shown in FIG7, the organic polymer layer 52 (i.e., the second organic polymer layer) located on the side of the first metal layer 51 near the signal electrode 2 also covers at least a portion of the side surface of the reference electrode (first reference electrode 3 or second reference electrode 4) near the signal electrode 2. In other words, as shown in FIG7, the portion 522 of the second organic polymer layer covering the first side surface 512a extends toward the reference electrode (first reference electrode 3 or second reference electrode 4), and the extended portion 523 covers at least a portion of the side surface of the reference electrode (first reference electrode 3 or second reference electrode 4) near the signal electrode 2.

[0069] In some embodiments, referring to FIG11, the membrane bridge 5 further includes an adhesion layer 53, which is located between the first metal layer 51 and the organic polymer layer 52. The adhesion layer 53 is used to improve the adhesion between the first metal layer 51 and the organic polymer layer 52, and to prevent the first metal layer 51 from delaminating. Further, the adhesion layer 53 includes an inorganic dielectric layer such as a nitride layer or an oxide layer. The oxide layer is made of, for example, silicon dioxide (SiO2). The nitride layer is made of, for example, silicon nitride (SiN). x In practical applications, the option to set an attachment layer 53 can be selected based on specific needs.

[0070] In some embodiments, in order to improve the adhesion between the first metal layer 51 and the organic polymer layer 52, the thickness of the adhesion layer 53 is greater than or equal to 0.1 μm and less than or equal to 0.3 μm.

[0071] In some embodiments, referring to FIG12, the membrane bridge 5 further includes a protective layer 54 covering at least a portion of the surface of the organic polymer layer 52 on the side opposite to the first metal layer 51. In embodiments where the first metal layer 51 includes a bridge body 511, the protective layer 54, for example, covers the entire second bridge surface 511b of the bridge body 511. The protective layer 54 not only protects the organic polymer layer 52 but also enables stress modulation, increases the rigidity of the membrane bridge 5, and improves its resilience. Further, in some embodiments, the protective layer 54 includes an inorganic dielectric layer such as a nitride layer or an oxide layer. The oxide layer is made of, for example, silicon dioxide (SiO2). The nitride layer is made of, for example, silicon nitride (SiN). x ).

[0072] In some embodiments, the thickness of the protective layer 54 is greater than or equal to 0.1 μm and less than or equal to 0.3 μm.

[0073] In some embodiments, referring to FIG. 13, at least one through-hole 55 extending along its thickness is provided in the organic polymer layer 52. Further, in embodiments where the membrane bridge 5 also includes an adhesion layer 53 and / or a protective layer 54, each through-hole 55 also extends through the adhesion layer 53 and / or the protective layer 54. The through-holes 55 can balance the stress of the membrane bridge 5 and increase heat dissipation of the first metal layer 51. Further, in some embodiments, the through-hole 55 is a circular hole with a diameter greater than or equal to 5 μm and less than or equal to 20 μm. Of course, in practical applications, the through-hole 55 can also adopt other shapes and sizes depending on specific needs. It should be noted that under ideal process conditions, the through-hole 55 is a straight through-hole, but in actual process, a tapered hole as shown in FIG. 13 may be obtained. Additionally, in some embodiments, multiple through-holes 55 can be arranged in an array relative to the bridge surface of the membrane bridge 5.

[0074] In some embodiments, referring to FIG14, the membrane bridge 5 further includes a second metal layer 56, which covers the surface of the organic polymer layer 52 opposite to the first metal layer 51 and is connected to the first metal layer 51 through various through-holes 55. Further, in embodiments where the membrane bridge 5 also includes a protective layer 54, the second metal layer 56 covers the surface of the protective layer 54 opposite to the organic polymer layer 52. The second metal layer 56 improves the rigidity and resilience of the membrane bridge 5 and increases the heat dissipation area, thereby further increasing the heat dissipation of the first metal layer 51.

[0075] The fabrication methods of the microelectromechanical system switches provided in the above embodiments are described in detail below. Specifically, the fabrication method of the microelectromechanical system switch shown in FIG11 includes, for example, the following steps:

[0076] S101. A whole layer of signal electrode 2 is formed on the substrate 1 by sputtering or electroplating, and a patterning process is performed on it to form a pattern of signal electrode 2.

[0077] The patterning process described above, for example, employs a wet etching process. The overall thickness of the signal electrode 2 is, for example, 1–3 μm.

[0078] S102. Deposit an entire layer of interlayer dielectric layer 6 on the substrate 1 on which the signal electrode 2 is formed, and perform a patterning process on it to form a pattern of interlayer dielectric layer 6.

[0079] The thickness of the interlayer dielectric layer 6 is, for example, 0.1–0.2 μm. The material of the interlayer dielectric layer 6 includes, for example, silicon dioxide (SiO2) or silicon nitride (SiN). x )etc.

[0080] S103. A sacrificial layer is formed on the substrate 1 on which the signal electrode 2 and the interlayer dielectric layer 6 are formed by spin coating, and a patterning process is performed on it to form a pattern of the sacrificial layer.

[0081] The sacrificial layer has a total thickness of approximately 1.5 μm. Materials used for the sacrificial layer include, for example, photoresist and polyimide.

[0082] S104. The first metal layer 51 is formed on the sacrificial layer by sputtering or electroplating, and then patterned to form a pattern of the first metal layer 51.

[0083] S105. A whole layer of adhesion layer 53 is deposited, a whole layer of organic polymer layer 52 is formed by coating, and a whole layer of photoresist mask is formed by spin coating, and a patterning process is performed on the whole layer of photoresist mask.

[0084] S106. A patterning process is performed on the entire organic polymer layer 52 and the entire adhesion layer 53 using a photoresist mask to form patterns of the organic polymer layer 52 and the adhesion layer 53.

[0085] S107, Sacrifice layer release.

[0086] The fabrication method for the microelectromechanical system switch shown in Figure 12 is similar to the method described above, except that the deposition of the entire protective layer 54 is added in step S105 above.

[0087] Furthermore, for the fabrication method of the microelectromechanical system switch shown in Figure 13, after step S106 and before step S107, a fabrication step of through hole 55 is added.

[0088] Furthermore, in the fabrication method of the microelectromechanical system switch shown in Figure 14, after the fabrication step of the through-hole 55 and before the aforementioned step S107, a fabrication step of the second metal layer 56 is added. This step can be performed using the same method as step S104. The overall thickness of the second metal layer 56 is, for example, greater than 0.6 μm.

[0089] The microelectromechanical system switch shown in Figure 3 is fabricated by, for example, the following steps:

[0090] S201. A whole layer of signal electrode 2 is formed on substrate 1 by sputtering or electroplating, and a patterning process is performed on it to form a pattern of signal electrode 2.

[0091] S202. Deposit an entire layer of interlayer dielectric layer 6 on the substrate 1 on which the signal electrode 2 is formed, and perform a patterning process on it to form a pattern of interlayer dielectric layer 6.

[0092] S203. A complete sacrificial layer is formed by spin coating, and a patterning process is performed on it to form a pattern of the sacrificial layer.

[0093] S204. An organic polymer layer 52 is formed on the sacrificial layer by coating.

[0094] The organic polymer layer 52 has a total thickness of 0.5 μm or more and 2 μm or less.

[0095] S205. Perform a patterning process on the entire organic polymer layer 52 to form a pattern of the organic polymer layer 52.

[0096] For example, dry etching is used for patterning processes.

[0097] S206. The first metal layer 51 is formed on the organic polymer layer 52 by sputtering or electroplating, and then patterned to form a pattern of the first metal layer 51.

[0098] S207, Sacrificial layer release.

[0099] The fabrication methods of the microelectromechanical system switches used in other embodiments are similar to those described above, and will not be repeated here.

[0100] It should be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A microelectromechanical system switch, characterized in that, The device includes a substrate, a signal electrode disposed on the substrate, two reference electrodes located on both sides of the signal electrode, and a membrane bridge disposed on the side of the reference electrode away from the substrate and connected to at least one of the reference electrodes; wherein the membrane bridge includes a first metal layer and at least one organic polymer layer, and the elastic modulus of the organic polymer layer is less than the elastic modulus of the first metal layer. The first metal layer has at least a portion of its surface covered with the organic polymer layer on at least one side of the side facing away from and near the signal electrode.

2. The microelectromechanical system switch according to claim 1, characterized in that, The organic polymer layer includes a polyimide layer.

3. The microelectromechanical system switch according to claim 1, characterized in that, The first metal layer includes a bridge body disposed on the side of the signal electrode opposite to the substrate, and at least one connecting arm for connecting one end of the bridge body to the reference electrode. The bridge body has a first bridge surface and a second bridge surface, respectively, on the side close to and away from the signal electrode. The organic polymer layer on the side of the first metal layer close to the signal electrode covers at least a portion of the first bridge surface; the organic polymer layer on the side of the first metal layer away from the signal electrode covers at least a portion of the second bridge surface.

4. The microelectromechanical system switch according to claim 3, characterized in that, Each of the connecting arms has a first side and a second side, respectively, that are close to and away from the signal electrode; the first side intersects with the first bridge surface, and the second side intersects with the second bridge surface; The organic polymer layer located on the side of the first metal layer near the signal electrode covers the intersection of the first side surface and the first bridge surface, as well as at least a portion of the first side surface and at least a portion of the first bridge surface located on both sides of the intersection line. The organic polymer layer located on the side of the first metal layer opposite to the signal electrode covers the intersection of the second side surface and the second bridge surface, as well as at least a portion of the second side surface and at least a portion of the second bridge surface located on both sides of the intersection line.

5. The microelectromechanical system switch according to claim 4, characterized in that, The orthographic projection of the portion of the organic polymer layer covering the first bridge surface on the substrate is offset from the orthographic projection of the signal electrode on the substrate.

6. The microelectromechanical system switch according to claim 4, characterized in that, The portion of the organic polymer layer covering the second bridge surface has its orthographic projection on the substrate offset from the orthographic projection of the signal electrode on the substrate.

7. The microelectromechanical system switch according to claim 4, characterized in that, The bridge body has two connecting arms, namely a first connecting arm and a second connecting arm, and the two ends of the bridge body are respectively connected to the two reference electrodes through the first connecting arm and the second connecting arm; The portion of the organic polymer layer covering the first bridge surface includes a first edge portion, a second edge portion, and at least one first support portion, wherein the first support portion is connected between the first edge portion and the second edge portion.

8. The microelectromechanical system switch according to claim 4, characterized in that, The bridge body has two connecting arms, namely a first connecting arm and a second connecting arm, and the two ends of the bridge body are respectively connected to the two reference electrodes through the first connecting arm and the second connecting arm; The portion of the organic polymer layer covering the second bridge surface includes a third edge portion, a fourth edge portion, and at least one second support portion, the second support portion being connected between the third edge portion and the fourth edge portion.

9. The microelectromechanical system switch according to claim 4, characterized in that, The organic polymer layer located on the side of the first metal layer near the signal electrode also covers at least a portion of the side of the reference electrode near the signal electrode.

10. The microelectromechanical system switch according to claim 1, characterized in that, The membrane bridge further includes an adhesion layer located between the first metal layer and the organic polymer layer.

11. The microelectromechanical system switch according to claim 10, characterized in that, The adhesion layer includes a nitride layer or an oxide layer.

12. The microelectromechanical system switch according to claim 10, characterized in that, The thickness of the adhesion layer is greater than or equal to 0.1 μm and less than or equal to 0.3 μm.

13. The microelectromechanical system switch according to claim 1, characterized in that, The membrane bridge further includes a protective layer that covers at least a portion of the surface of the organic polymer layer on the side opposite to the first metal layer.

14. The microelectromechanical system switch according to claim 13, characterized in that, The protective layer includes a nitride layer or an oxide layer.

15. The microelectromechanical system switch according to any one of claims 1-14, characterized in that, The organic polymer layer has at least one through-hole extending along its thickness.

16. The microelectromechanical system switch according to claim 15, characterized in that, The through hole is a circular hole with a diameter greater than or equal to 5 μm and less than or equal to 20 μm.

17. The microelectromechanical system switch according to claim 15, characterized in that, The membrane bridge further includes a second metal layer, which covers the surface of the organic polymer opposite to the first metal layer and is connected to the first metal layer through each of the through holes.

18. The microelectromechanical system switch according to claim 1, characterized in that, The thickness of the first metal layer is greater than or equal to 1 μm and less than or equal to 3 μm.

19. The microelectromechanical system switch according to claim 1, characterized in that, The thickness of the organic polymer layer located on the side of the first metal layer near the signal electrode is greater than or equal to 0.5 μm and less than or equal to 2 μm.

20. The microelectromechanical system switch according to claim 1, characterized in that, The thickness of the organic polymer layer located on the side of the first metal layer opposite to the signal electrode is greater than or equal to 1 μm and less than or equal to 20 μm.

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