MEMS resonator
By designing the structure of gradient gap in the MEMS resonator, the ARDE characteristics of deep reactive ion etching are used to solve the problems of etching inhomogeneity and silicon bridge residues, and the processing performance is improved.
Patent Information
- Application Number
- CN202323576769.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-25
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2033-12-25
AI Technical Summary
In the deep reactive ion etching process of MEMS resonators, the depth-to-face ratio-related etching phenomenon leads to etching unevenness, and silicon bridge residues may occur, affecting the device processing performance.
The gap between the electrode assembly and the resonant assembly is designed as a gradient gap. Through the transition of the inclined section and the straight section, the probability of silicon bridge residue is reduced and the uniformity of etching is improved.
Through this design, the risk of silicon bridge residue is reduced, the uniformity of etching and the processing performance of the device are improved, and the processing poor are reduced.
Smart Images
Figure CN222192324U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of micro-electromechanical systems, in particular to a MEMS resonator. Background Art
[0002] MEMS resonators are resonators manufactured based on micro-electromechanical systems (MEMS) technology. A resonator is a device that can resonate at a specific frequency and is commonly used in electronic devices such as oscillators, filters, and clock generators. MEMS resonators combine micro-nano-scale mechanical structures with electronic control circuits, and have the advantages of small size, low power consumption, and high frequency stability.
[0003] In the processing of MEMS resonators, the deep reactive ion etching (DRIE) process is usually used to remove unnecessary materials to form the main structure of the MEMS resonator resonator component and electrode component. When the depth-to-width ratio of the structure is small, the etching rate is fast; when the depth-to-width ratio is large, the etching rate is slow; on small-sized graphics with a high aspect ratio, etching will stop completely. This phenomenon is called aspect ratio-dependent etching (ARDE), also known as the micro-loading effect. Uniformity is a parameter that measures the etching ability of the DRIE etching process on silicon wafers. When the etching is uneven, silicon bridge residues may appear. How to reduce the risk of silicon bridge residues through ARDE characteristics during the etching of MEMS resonators is an urgent problem to be solved. Utility Model Content
[0004] The purpose of the present application is to provide a MEMS resonator, which can reduce the probability of silicon bridge residues appearing during etching.
[0005] The present application provides a MEMS resonator, comprising an electrode assembly and a resonance assembly, wherein the resonance assembly comprises a resonator and a connecting beam, wherein the connecting beam is connected between adjacent resonators; wherein the electrode assembly and the resonator are spaced to form a first gap, and the electrode assembly and the connecting beam are spaced to form a second gap connected to the first gap, wherein the second gap comprises two inclined sections and a straight section, wherein the straight section is located between the two inclined sections, and the inclined section is located between the straight section and the first gap, wherein the width of the inclined section gradually increases from the first gap toward the straight section, and the width of the straight section is greater than the width of the second gap.
[0006] In an exemplary embodiment of the present application, the straight section includes a first side and a second side; the inclined section includes a third side and a fourth side; the first gap includes a fifth side and a sixth side; wherein the distance between the second side and the first side is smaller than the distance from the sixth side to the fifth side, and the distance from the fourth side to the third side gradually increases from the first gap toward the straight section.
[0007] In an exemplary embodiment of the present application, the connecting beam connects adjacent resonators to form a ring structure, and the resonators and the connecting beam are symmetrical along the center of the ring structure.
[0008] In an exemplary embodiment of the present application, the electrode assembly includes a driving electrode and a sensing electrode, the driving electrode is used to form a capacitive driving structure with the resonator, and the sensing electrode is used to form a capacitive sensing structure with the resonator.
[0009] In an exemplary embodiment of the present application, the driving electrode is arranged outside the annular structure, and the sensing electrode is arranged inside the annular structure.
[0010] In an exemplary embodiment of the present application, there are multiple resonators, the connecting beam is a straight beam structure, and adjacent connecting beams are perpendicular to each other.
[0011] In an exemplary embodiment of the present application, the electrode assembly further includes an anchor, one end of which is connected to the connecting beam, and the other end of which is extended away from the interior of the annular structure, and the other end of which is used to connect to the substrate.
[0012] In an exemplary embodiment of the present application, the electrode assembly and the anchor are spaced apart to form a third gap, and the second gap is connected to the third gap.
[0013] In an exemplary embodiment of the present application, the two corresponding connecting beams away from the center of the annular structure are connected to the anchor, the anchor is extended toward the center of the annular structure, the anchors are arranged at intervals, each of the anchors is provided with an anchor point at one end away from the connecting beam, and the anchor is connected to the substrate through a plurality of the anchor points.
[0014] In an exemplary embodiment of the present application, the two corresponding connecting beams away from the center of the annular structure are connected to the anchor, and the anchor is extended toward the center of the annular structure. The anchors are connected to each other at the center of the annular structure, and the center is configured as an anchor point. The anchor is connected to the substrate through the anchor point.
[0015] A MEMS resonator of the present application has the following beneficial effects: the electrode assembly can induce the resonator of the resonator assembly to vibrate, the connecting beam is connected between adjacent resonators, the electrode assembly and the resonator, the electrode assembly and the connecting beam are isolated through the first gap and the second gap, and the electrical signal interference between the electrode assembly and the resonator, and the electrode assembly and the connecting beam is avoided. A gradual gap is formed between the first gap and the second gap through two inclined sections and a straight section of the second gap, and a transition is made at the connection between the first gap and the second gap through the inclined section. Since DRIE has ARDE characteristics, such a design can reduce the probability of silicon bridge residues being formed at the connection, thereby improving the uniformity of etching, improving the device processing performance, and reducing processing defects.
[0016] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by the practice of the present application.
[0017] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0019] Figure 1 This is a structural schematic diagram of an embodiment of a MEMS resonator in an embodiment of the utility model;
[0020] Figure 2 is an enlarged schematic diagram of the first gap and the second gap in an embodiment of the utility model;
[0021] Figure 3 It is a structural schematic diagram of another embodiment of a MEMS resonator in the embodiment of the utility model.
[0022] Description of reference numerals:
[0023] Electrode assembly 100; driving electrode 110; sensing electrode 120; resonant assembly 200; resonator 210; connecting beam 220; first gap D1; fifth side 11; sixth side 12; second gap D2; straight section 21; first side 211; second side 212; inclined section 22; third side 221; fourth side 222; annular structure 300; center 310; anchor 400; anchor point 410; third gap D3. DETAILED DESCRIPTION
[0024] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be more comprehensive and complete and fully convey the concept of example embodiments to those skilled in the art.
[0025] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the application.
[0026] The present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be understood as limiting the present application.
[0027] It should be noted that the "multiple" mentioned in this article refers to two or more. "And / or" describes the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.
[0028] MEMS resonators are resonators manufactured based on micro-electromechanical systems (MEMS) technology. A resonator is a device that can resonate at a specific frequency and is commonly used in electronic devices such as oscillators, filters, and clock generators. MEMS resonators combine micro-nano-scale mechanical structures with electronic control circuits, and have the advantages of small size, low power consumption, and high frequency stability.
[0029] In the processing of MEMS resonators, unnecessary materials are usually removed through deep reactive ion etching (DRIE) to form the main structure of the MEMS resonator resonator component and electrode component. When the depth-to-width ratio of the structure is small, the etching rate is fast; when the depth-to-width ratio is large, the etching rate is slow; on small-sized graphics with a high aspect ratio, etching will stop completely. This phenomenon is called aspect ratio-dependent etching (ARDE), also known as the micro-loading effect. Uniformity is a parameter that measures the etching ability of the DRIE etching process on silicon wafers. When the etching is uneven, silicon bridge residues may appear. How to reduce the risk of silicon bridge residues through ARDE characteristics during the etching of MEMS resonators is an urgent problem to be solved.
[0030] In order to solve the above technical problems, refer to Figures 1 to 3 As shown, a MEMS resonator is provided, including an electrode assembly 100 and a resonance assembly 200, the resonance assembly 200 includes a resonator 210 and a connecting beam 220, and the connecting beam 220 is connected between adjacent resonators 210; wherein, the electrode assembly 100 and the resonator 210 are spaced to form a first gap D1, and the electrode assembly 100 and the connecting beam 220 are spaced to form a second gap D2 connected to the first gap D1, the second gap D2 includes two inclined sections 22 and a straight section 21, the straight section 21 is located between the two inclined sections 22, the inclined section 22 is located between the straight section 21 and the first gap D1, the width of the inclined section 22 gradually increases from the first gap D1 to the straight section 21, and the width of the straight section 21 is greater than the width of the second gap D2.
[0031] The electrode assembly 100 can induce the resonator 210 of the resonant assembly 200 to vibrate, and the electrode assembly 100 and the resonator 210, and the electrode assembly 100 and the connecting beam 220 are isolated through the first gap D1 and the second gap D2. A gradual gap is formed between the first gap D1 and the second gap D2 through two inclined sections 22 and a straight section 21 of the second gap D2. At the connection between the first gap D1 and the second gap D2, a transition is made through the inclined section 22. Such a design can reduce the probability of silicon bridge residues being formed at the connection, thereby improving the uniformity of etching, improving the processing performance of the device, and reducing processing defects.
[0032] The silicon bridge residue means that the gap is not etched open, so that there is a partial connection between the two sides of the gap. The first gap D1 can be the connection between the electrode assembly 100 and the resonator 210, and the second gap D2 is the connection between the electrode assembly 100 and the connecting beam 220.
[0033] In some embodiments, the MEMS resonator is made of known semiconductor materials, such as silicon, single crystal silicon, polycrystalline silicon, etc.; further, the MEMSMEMS resonator can also be formed in or on an insulator using known photolithography, etching, deposition and / or doping techniques, and the insulator can specifically be a semiconductor substrate. In the processing technology of the MEMSMEMS resonator, the deep reactive ion etching (English name Deep Reactive Ion Etching, referred to as DRIE) process is usually used, which is an etching technology used for micro-nano processing. It etches materials using ion beams and chemical reactions to produce high-depth micron and nano structures on silicon wafers, and removes unnecessary materials through the deep reactive ion etching process to form the resonant component 200 of the MEMS resonator, such as the connecting beam 220, the resonator 210, etc.
[0034] In some embodiments, reference Figure 2 As shown, the straight section 21 includes a first side 211 and a second side 212, the inclined section 22 includes a third side 221 and a fourth side 222, and the first gap D1 includes a fifth side 11 and a sixth side 12. Among them, the distance between the second side 212 and the first side 211 is greater than the distance between the sixth side 12 and the fifth side 11, and the distance between the fourth side 222 and the third side 221 gradually increases from the first gap D1 to the straight section 21. Through the above design, the first side 211, the third side 221 and the fifth side 11 can be formed at one time, and then the second side 212, the fourth side 222 and the sixth side 12 can be adjusted to form the first gap D1, the inclined section 22 and the straight section 21 respectively. Such a design can reduce the difficulty of forming the first gap D1 and the second gap D2.
[0035] In some embodiments, reference Figure 1 and Figure 3 As shown, the connecting beam 220 connects the adjacent resonators 210 to form a ring structure 300, and the resonators 210 and the connecting beam 220 are symmetrical along the center 310 of the ring structure 300. The device performance degradation caused by the photolithography error can be reduced, and more resonators 210 can be set, thereby increasing the resonance strength of the MEMS resonator.
[0036] In some embodiments, reference Figure 1 and Figure 3As shown, the electrode assembly 100 includes a driving electrode 110 and a sensing electrode 120. The driving electrode 110 is used to form a capacitive driving structure with the resonator 210, and the sensing electrode 120 is used to form a capacitive sensing structure with the resonator 210. The driving electrode 110 applies an AC voltage to induce the resonator 210 to resonate. The resonance has one or more resonant frequencies. A sensing capacitor is formed between the sensing electrode 120 and the resonator 210, and the sensing electrode 120 is used to output a resonant frequency electrical signal. The MEMS resonator is also provided with a driving circuit connected to the driving electrode 110, and a sensing circuit connected to the sensing electrode 120. The driving circuit and the sensing circuit may be conventional, well-known types, or may be any type known now or developed later, which will not be elaborated here.
[0037] In some embodiments, the number of driving electrodes 110 and sensing electrodes 120 is not limited; the shape of the electrodes is also not limited, and can be set according to the chip area and electrode arrangement, which is not limited here. For those skilled in the art, the location of the driving electrode 110 can also be swapped with the location of the sensing electrode 120, which is not limited here.
[0038] In some embodiments, the driving electrode 110 is disposed outside the annular structure 300, and the sensing electrode 120 is disposed inside the annular structure 300. This can reduce the parasitic capacitance between the driving electrode 110 and the sensing electrode 120, and improve the performance of the MEMS resonator.
[0039] In some embodiments, reference Figure 1 and Figure 3 As shown, there are multiple resonators 210, and the connecting beams 220 are straight beam structures, and adjacent connecting beams 220 are perpendicular to each other. The number of the exemplary resonators 210 and connecting beams 220 is 12, and the adjacent resonators 210 are perpendicularly connected to each other through the connecting beams 220 to form a cross-shaped rectangular ring array structure. The multiple resonators 210 and connecting beams 220 are symmetrical structures with the center of the ring structure 300, so that the weight of the two ends of the connecting beam 220 can be the same, which is convenient for anchoring and increasing the stability of the structure.
[0040] In some embodiments, reference Figure 1 and Figure 3As shown, the electrode assembly 100 further includes an anchor 400, one end of which is connected to the connecting beam 220, and the other end of which is extended away from the inner part of the annular structure, and the other end of which is used to connect to the substrate. The resonator 210 and the substrate are connected by the anchor 400, which anchors the resonator 210, thereby supporting the connecting beam 220 and the resonator 210 of the entire MEMS resonator. The setting mode of the anchor 400, such as shape, position, quantity, etc., is set according to the arrangement mode and quantity of the resonator 210 and the connecting beam 220.
[0041] In some embodiments, reference Figure 1 and Figure 3 As shown, the electrode assembly 100 and the anchor 400 are spaced to form a third gap D3, and the second gap D2 is connected to the third gap D3. The third gap D3 can reduce the risk of silicon bridge residues between the electrode assembly 100 and the anchor 400, further improving the performance of the MEMS resonator.
[0042] In some embodiments, reference Figure 1 As shown, two connecting beams 220 corresponding to the center 310 away from the annular structure 300 are connected to the anchor 400, and the anchor 400 is extended to the center 310 of the annular structure 300. The anchors 400 are arranged at intervals, and each anchor 400 is provided with an anchor point 410 at one end away from the connecting beam 220, and the anchor 400 is connected to the substrate through multiple anchor points 410. The connecting beam 220 and the resonator 210 are symmetrical structures with the center 310 as the center, and an anchor 400 is arranged on each protrusion on the connecting beam 220 away from the center 310. The anchor 400 is connected to the center 310 of the connecting beam 220 so that the weight of the two ends of the connecting beam 220 is the same, which is convenient for anchoring and increasing the stability of the structure. Further, the number of the resonator 210 is multiple, and the connecting beam 220 is a straight beam structure. Adjacent connecting beams 220 are perpendicular to each other, and the connecting beam 220 connects adjacent resonators 210 to form a second annular structure 300. Further, the second annular structure 300 is a cross-shaped rectangular ring array structure, and the second annular structure 300 includes mutually connected protrusions and recesses, the protrusions are configured as three connecting beams 220, the recesses are configured as two connecting beams 220, and adjacent protrusions and recesses share one connecting beam 220. Through the above design, a larger number of resonators 210 can be set, thereby increasing the resonance strength of the MEMS resonator.
[0043] In another embodiment, referring to Figure 3As shown, two connecting beams 220 corresponding to the center 310 away from the annular structure 300 are connected to the anchor 400, and the anchor 400 is extended to the center 310 of the annular structure 300. The anchors 400 are connected to each other at the center 310 of the annular structure 300, and the center 310 is configured as an anchor point 410. The anchor 400 is connected to the substrate through the anchor point 410. Further, the number of the protrusions and the recessed parts is each, and the number of the anchors 400 is, and one anchor 400 is arranged on the connecting beam 220 away from the center 310 on each protrusion, and multiple anchors 400 are connected to each other at the center 310 of the second annular structure 300 to form an integrated structure. Through the above design, multiple anchors 400 are connected to form an integrated structure, and on the basis of increasing the stability of the connection between the resonant component 200 and the substrate, the number of anchor points 410 can be reduced, and the process difficulty of connecting the anchor 400 to the substrate can be reduced.
[0044] In the present application, a gradual gap is formed between the first gap D1 and the second gap D2 by two inclined sections 22 and a straight section 21 of the second gap D2. At the connection between the first gap D1 and the second gap D2, a transition is made by the inclined section 22. Since DRIE has ARDE characteristics, such a design can reduce the probability of silicon bridge residues being formed at the connection, thereby improving the uniformity of etching, improving the processing performance of the device, and reducing processing defects. The above design can form the first side 211, the third side 221 and the fifth side 11 at one time, and then adjust the second side 212, the fourth side 222 and the sixth side 12 to form the first gap D1, the inclined section 22 and the straight section 21 respectively. Such a design can reduce the difficulty of forming the first gap D1 and the second gap D2.
[0045] In this application, unless otherwise clearly specified and limited, the terms "disposed (provided with)", "connected" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0046] In the description of this specification, the description of reference terms such as "some embodiments" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.
[0047] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application. Therefore, any changes or modifications made in accordance with the claims and description of the present application should fall within the scope of the patent of this application.
Claims
1. A MEMS resonator, characterized in that: include: Electrode assembly; A resonant component, the resonant component comprising a resonator and a connecting beam, wherein the connecting beam is connected between adjacent resonators; The electrode assembly and the resonator are spaced to form a first gap, the electrode assembly and the connecting beam are spaced to form a second gap connected to the first gap, the second gap includes a straight section and two inclined sections, the straight section is located between the two inclined sections, the inclined section is located between the straight section and the first gap, the width of the inclined section gradually increases from the first gap to the straight section, and the width of the straight section is greater than the width of the second gap.
2. The MEMS resonator according to claim 1, characterized in that: The straight section includes a first side and a second side; The inclined section includes a third side and a fourth side; The first gap includes the fifth side and the sixth side; The distance between the second side and the first side is smaller than the distance between the sixth side and the fifth side, and the distance between the fourth side and the third side gradually increases from the first gap toward the straight section.
3. The MEMS resonator according to claim 1, characterized in that: The connecting beam connects the adjacent resonators to form a ring structure, and the resonators and the connecting beam are symmetrical along the center of the ring structure.
4. The MEMS resonator according to claim 3, characterized in that: The electrode assembly includes a driving electrode and a sensing electrode. The driving electrode is used to form a capacitive driving structure with the resonator, and the sensing electrode is used to form a capacitive sensing structure with the resonator.
5. The MEMS resonator according to claim 4, characterized in that: The driving electrode is arranged outside the annular structure, and the sensing electrode is arranged inside the annular structure.
6. The MEMS resonator according to claim 3, characterized in that: The number of the resonators is multiple, the connecting beams are straight beam structures, and adjacent connecting beams are perpendicular to each other.
7. The MEMS resonator according to claim 6, characterized in that: The MEMS resonator further includes an anchor, one end of which is connected to the connecting beam, the other end of which is extended inwardly away from the annular structure, and the other end of which is used to connect to a substrate.
8. The MEMS resonator according to claim 7, characterized in that: The electrode assembly and the anchor are spaced apart to form a third gap, and the second gap is communicated with the third gap.
9. The MEMS resonator according to claim 7, characterized in that: The two corresponding connecting beams away from the center of the annular structure are connected to the anchors, and the anchors are extended toward the center of the annular structure. The anchors are arranged at intervals, and each of the anchors is provided with an anchor point at one end away from the connecting beams. The anchors are connected to the substrate through multiple anchor points.
10. The MEMS resonator according to claim 7, characterized in that: The two corresponding connecting beams away from the center of the annular structure are connected to the anchor, and the anchor is extended toward the center of the annular structure. The anchors are connected to each other at the center of the annular structure, and the center is configured as an anchor point. The anchor is connected to the substrate through the anchor point.