MEMS resonance device and manufacturing method thereof, MEMS device and electronic equipment

Abstract

The invention provides an MEMS resonance device, a manufacturing method of the MEMS resonance device, an MEMS device and electronic equipment. The MEMS resonance device comprises a substrate, a first insulating layer, a resonance body and a covering structure which are stacked, the resonant body comprises an oscillator and an anchor point which are arranged on the same layer and connected; the covering structure comprises an electric connection part, and the projection of the electric connection part on the resonance body is located in the anchor point range; the substrate is provided with a first cavity, and / or the covering structure is provided with a second cavity; the projection of the first cavity on the resonance body is overlapped with the anchor point; the projection of the second cavity on the resonant body is closer to the vibrator than the projection of the electric connection part on the resonant body, the projection of the second cavity on the resonant body is overlapped with the anchor point, and the projection of the second cavity on the resonant body is not overlapped with the vibrator. According to the invention, the loss of elastic waves propagated to the upper part and / or the lower part of the anchor point can be inhibited, so that the loss of the anchor point is better improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a MEMS resonance device and a manufacturing method thereof, a MEMS device and an electronic device. Background Art

[0002] A MEMS device such as a resonator, a clock device, a crystal oscillator or a gyroscope may generally include a MEMS resonant device and a circuit, and the MEMS resonant device is electrically connected to the circuit. Exemplarily, when the MEMS device is a clock device, the clock device may include a MEMS resonant device and a holding circuit. The holding circuit provides an oscillation excitation for the MEMS resonant device, and the MEMS resonant device may generate a clock signal after receiving the oscillation excitation.

[0003] The MEMS resonant device may include a stacked substrate, a resonant body, and a covering structure. The resonant body includes a vibrator and an anchor point connected to the vibrator. The anchor point is fixed between the substrate and the covering structure, a part of the vibrator is fixed to the anchor point, and the other part of the vibrator is suspended. External excitation can be loaded on the vibrator, and the vibrator will generate an elastic wave, which will propagate toward the anchor point along the connecting structure between the vibrator and the anchor point. The elastic wave propagating to the anchor point will propagate above and below the anchor point and in the direction away from the vibrator toward the anchor point, thereby causing anchor point loss. This will result in a large energy loss in the MEMS resonant device, resulting in a low quality factor (Quality Factor, Q value).

[0004] In the related art, the anchor loss is mainly improved by suppressing the propagation of elastic waves. However, the improvement of the anchor loss is insufficient, resulting in a still low Q value of the MEMS resonant device. Summary of the invention

[0005] In order to solve the above technical problems, the present application provides a MEMS resonance device and a manufacturing method thereof, a MEMS device and an electronic device, which can suppress the loss of elastic waves propagating above and / or below the anchor point, thereby better improving the anchor point loss.

[0006] In a first aspect of the present application, a MEMS resonant device is provided, comprising: a stacked substrate, a first insulating layer, a resonant body, and a covering structure. The resonant body comprises a vibrator and an anchor point which are arranged in the same layer and connected. The covering structure comprises an electrical connection portion, and the projection of the electrical connection portion on the resonant body is located within the range of the anchor point. When the MEMS resonant device of the present application is used, the vibrator in the resonant body can receive external excitation and generate vibration. Elastic waves are generated during the vibration of the vibrator, and part of the elastic waves propagate from the vibrator to the anchor point connected to the vibrator.

[0007] In a possible implementation, a first cavity is provided on the substrate, and the projection of the first cavity on the resonator overlaps with the anchor point. After the elastic wave propagates to the anchor point, it will also propagate toward the bottom of the anchor point. Since the substrate, the first insulating layer, the resonator, the second insulating layer and the covering structure are stacked, the substrate is provided below the resonator. Moreover, the projection of the first cavity provided on the substrate on the resonator overlaps with the anchor point, that is, the first cavity is located below the anchor point, so when the elastic wave propagating to the anchor point propagates toward the bottom of the anchor point, the elastic wave will propagate to the first cavity. The first cavity is usually filled with gas, and the propagation energy of the elastic wave in the gas medium is much smaller than the propagation energy in the solid medium. When the elastic wave propagates from the anchor point to the first cavity, its propagation medium changes from the solid medium to the gas medium. The heterogeneous propagation medium can suppress the loss of the elastic wave propagating downward, thereby reducing the energy lost from the anchor point, that is, improving the anchor point loss, and then improving the Q value of the MEMS resonant device.

[0008] In another possible implementation, a second cavity is provided on the covering structure, and the projection of the second cavity on the resonator is closer to the vibrator than the projection of the electrical connection portion on the resonator, and the projection of the second cavity on the resonator overlaps with the anchor point, and the projection of the second cavity on the resonator does not overlap with the vibrator. After the elastic wave propagates to the anchor point, it will also propagate toward the top of the anchor point. Since the substrate, the first insulating layer, the resonator, the second insulating layer and the covering structure are stacked, the covering structure is arranged above the resonator. Moreover, the projection of the second cavity provided on the covering structure on the resonator overlaps with the anchor point, that is, the second cavity is located above the anchor point. Therefore, when the elastic wave propagating to the anchor point propagates above the anchor point, the elastic wave will propagate to the second cavity, and the second cavity can be in a high vacuum state and contain a small amount of hydrogen, and its pressure is less than 1Pa. Therefore, when the elastic wave propagates from the anchor point to the second cavity, its propagation medium changes, thereby suppressing the loss of the elastic wave propagating upward, thereby reducing the energy lost from the anchor point, that is, improving the anchor point loss.

[0009] In another possible implementation, a first cavity is provided on the substrate, and a second cavity is provided on the cover structure. The gas in the first cavity can suppress the loss of elastic waves propagating downward, and the gas in the second cavity can suppress the loss of elastic waves propagating upward, thereby improving the anchor loss.

[0010] In some possible implementations, a third cavity is provided on the anchor point. After the elastic wave propagates to the anchor point, it will also propagate in the direction of the anchor point away from the oscillator. Since the third cavity is provided on the anchor point, the third cavity can be in a high vacuum state and contains a small amount of H2 with a pressure less than 1Pa. Therefore, when the elastic wave propagates from the anchor point to the third cavity, its propagation medium changes, thereby suppressing the loss of the elastic wave propagating in the direction of the anchor point away from the oscillator.

[0011] Moreover, the projections of the third cavity and the second cavity on the anchor point do not overlap, and the projection of the third cavity on the resonator is farther away from the vibrator than the projection of the second cavity on the resonator. That is, the second cavity is closer to the vibrator than the third cavity. After the elastic wave propagating from the vibrator is transmitted from the anchor point toward the first end of the vibrator, it can propagate above the anchor point. Since the second cavity is closer to the vibrator, the second cavity can well suppress the loss of the elastic wave propagating upward.

[0012] In addition, the projection of the cavity surface of the first cavity close to the first insulating layer on the resonator overlaps with the first part of the anchor points. The first part of the anchor points can be the part of the anchor points between the first end of the anchor point facing the vibrator and the third cavity surface. After the elastic wave propagating from the vibrator is transmitted to the anchor point from the first end of the anchor point, it can propagate below the anchor point. The first cavity is located below the first part of the anchor points, thereby suppressing the loss of the elastic wave propagating downward. It can be seen that the first cavity located below the anchor point, the second cavity located above the anchor point, and the third cavity located on the anchor point can suppress the loss of the elastic wave in three directions respectively, thereby further improving the anchor point loss.

[0013] In some possible implementations, the size of the first cavity along the thickness direction of the substrate is smaller than the thickness of the substrate. In this way, at least one of the surface of the substrate facing the first insulating layer and the surface of the substrate facing away from the first insulating layer is a complete surface, that is, a surface without any cavity, so that the substrate can provide sufficient support for the first insulating layer.

[0014] Moreover, the first cavity is arranged on the side of the substrate facing away from the first insulating layer. That is to say, there is a gap between the cavity surface of the first cavity close to the first insulating layer and the surface of the substrate facing the first insulating layer. In this way, when making a MEMS resonant device, the first insulating layer, the resonator, the second insulating layer and the covering structure can be made in sequence on the substrate without etching the first cavity. Next, the first cavity is etched on the surface of the substrate facing away from the first insulating layer. Since the surface of the substrate facing the first insulating layer can provide sufficient support for the first insulating layer, the size of the first cavity can be set to be larger, thereby improving the suppression of elastic wave loss.

[0015] In some possible implementations, the first insulating layer includes a first sub-insulating layer and a second sub-insulating layer, a gap is provided between the first sub-insulating layer and the second sub-insulating layer, the gap is connected to the third cavity, and the second sub-insulating layer is closer to the vibrator than the first sub-insulating layer; the projection of the cavity surface of the first cavity close to the first insulating layer on the first insulating layer covers the second sub-insulating layer. The elastic wave propagating to the anchor point can propagate to the third cavity along the direction away from the vibrator on the anchor point. Since the gap is connected to the third cavity, the elastic wave propagating downward will propagate to the substrate through the second sub-insulating layer. Since the projection of the cavity surface of the first cavity close to the first insulating layer on the first insulating layer covers the second sub-insulating layer, it can be seen that the area of ​​the cavity surface of the first cavity close to the first insulating layer is larger than the surface area of ​​the second sub-insulating layer, thereby the elastic wave propagating from the second sub-insulating layer can be well suppressed.

[0016] In some possible implementations, the dimension of the end of the first cavity away from the first insulating layer along the first direction is greater than the dimension of the end of the first cavity close to the first insulating layer along the first direction, and the first direction is the arrangement direction of the anchor point and the vibrator. In other words, the dimension of the cavity mouth of the first cavity along the first direction is greater than the dimension of the bottom of the first cavity along the first direction. Since the first cavity is formed by etching after the first insulating layer, the resonator, the second insulating layer and the covering structure are manufactured, the first cavity can be etched by a wet etching process, thereby reducing the processing cost.

[0017] In some possible implementations, the first cavity is disposed on a side of the substrate facing the first insulating layer. In this way, the elastic wave propagating downward from the anchor point can propagate to the first cavity after passing through the first sub-insulating layer, thereby reducing the situation where the elastic wave does not propagate along the substrate, and thus reducing the situation where the elastic wave propagates in more solid materials and causes large losses. Therefore, the suppressive effect of the gas in the first cavity on the elastic wave can be further improved.

[0018] On this basis, the first insulating layer includes a first sub-insulating layer and a second sub-insulating layer, there is a gap between the first sub-insulating layer and the second sub-insulating layer, the gap is connected to the third cavity, the second sub-insulating layer is closer to the vibrator than the first sub-insulating layer; the projection of the first cavity on the first insulating layer is within the range of the second sub-insulating layer. In this way, there is a partial area where the substrate contacts the second sub-insulating layer without the first cavity, and this partial area can provide support for the second sub-insulating layer.

[0019] In some other possible implementations, the first cavity may be provided on the substrate and extend from a side of the substrate facing the first insulating layer to a side of the substrate facing away from the first insulating layer. In this case, the projection of the first cavity in the second sub-insulating layer may be located within the range of the second sub-insulating layer.

[0020] In some possible implementations, the covering structure further includes a second insulating layer located between the resonator and the electrical connection portion, and the second insulating layer may be disposed above the resonator, and the second insulating layer is in contact with the resonator. A hollow region is formed on the second insulating layer, and the second cavity is located in the hollow region. In this way, when the elastic wave propagating to the anchor point propagates toward the top of the anchor point, the elastic wave propagating upward can propagate directly from the anchor point to the second cavity, and the second cavity can effectively suppress the loss of this part of the elastic wave.

[0021] Moreover, the covering structure also forms a fourth cavity in the hollow area, and the projection of the fourth cavity on the resonator covers part of the anchor point and the vibrator. Regarding the positional relationship between the second cavity and the fourth cavity, in a possible implementation, the fourth cavity is arranged on the same layer as the second cavity and is connected. In this way, the fourth cavity can provide an escape space for the vibration of the vibrator, and the second cavity can suppress the loss of elastic waves propagating toward the top of the anchor point. When the fourth cavity is arranged on the same layer as the second cavity and is connected, the projection of the connected second cavity and the fourth cavity on the resonator and the overlapping area of ​​the anchor point can be increased, thereby further improving the suppression of the loss of elastic waves.

[0022] In another possible implementation, the fourth cavity and the second cavity are in the same layer and are spaced apart. The covering structure may include a support portion, and the fourth cavity and the second through hole may be spaced apart by the support portion, thereby improving the support effect on other components of the covering structure except the support portion.

[0023] In some other possible implementations, the second cavity is located inside the covering structure, and there is a gap between the cavity surface of the second cavity close to the resonator and the surface of the covering structure facing the resonator. In this way, only the fourth cavity can be provided on the surface of the covering structure facing the second insulating layer, without the need to provide other cavities. This can increase the contact area between the covering structure and the second insulating layer, thereby increasing the support strength of the covering structure. Therefore, the present application can increase the support strength of the covering structure while suppressing the loss of elastic waves.

[0024] In some possible implementations, the MEMS resonant device further includes a carrier, which is disposed on a side of the substrate away from the first insulating layer, and covers the first cavity. In this way, on the one hand, the carrier can increase the thickness of the entire MEMS resonant device, thereby increasing the mechanical strength of the MEMS resonant device and reducing the situation where the MEMS resonant device is damaged by a large force during use. On the other hand, the carrier is disposed on a side of the substrate away from the first insulating layer and covers the first cavity, so that after the MEMS resonant device is packaged, the first cavity can be a sealed space. The sealed space can be a high vacuum space, which is conducive to better suppressing anchor point loss.

[0025] According to a second aspect of the present application, a method for manufacturing a MEMS resonant device is provided, the method comprising: providing an SOI, the SOI comprising a stacked substrate, a sacrificial layer and a resonant body layer; etching the resonant body layer to form a resonant body, the resonant body comprising an oscillator and an anchor point that are arranged in the same layer and connected; manufacturing a covering structure on the resonant body, and etching the sacrificial layer to form a first insulating layer; the covering structure comprises an electrical connection portion, the projection of the electrical connection portion on the resonant body is located within the range of the anchor point.

[0026] In a possible implementation, a first cavity is provided on the substrate, and the projection of the first cavity on the resonator overlaps with the anchor point. After the elastic wave propagates to the anchor point, it will also propagate toward the bottom of the anchor point. Since the substrate, the first insulating layer, the resonator, the second insulating layer and the covering structure are stacked, the substrate is provided below the resonator. Moreover, the projection of the first cavity provided on the substrate on the resonator overlaps with the anchor point, that is, the first cavity is located below the anchor point, so when the elastic wave propagating to the anchor point propagates toward the bottom of the anchor point, the elastic wave will propagate to the first cavity. The first cavity is usually filled with gas, and the propagation energy of the elastic wave in the gas medium is much smaller than the propagation energy in the solid medium. When the elastic wave propagates from the anchor point to the first cavity, its propagation medium changes from the solid medium to the gas medium. The heterogeneous propagation medium can suppress the loss of the elastic wave propagating downward, thereby reducing the energy lost from the anchor point, that is, improving the anchor point loss.

[0027] In another possible implementation, a second cavity is provided on the covering structure, and the projection of the second cavity on the resonator is closer to the vibrator than the projection of the electrical connection portion on the resonator, and the projection of the second cavity on the resonator overlaps with the anchor point, and the projection of the second cavity on the resonator does not overlap with the vibrator. After the elastic wave propagates to the anchor point, it will also propagate toward the top of the anchor point. Since the substrate, the first insulating layer, the resonator, the second insulating layer and the covering structure are stacked, the covering structure is arranged above the resonator. Moreover, the projection of the second cavity provided on the covering structure on the resonator overlaps with the anchor point, that is, the second cavity is located above the anchor point. Therefore, when the elastic wave propagating to the anchor point propagates above the anchor point, the elastic wave will propagate to the second cavity, and the second cavity can be in a high vacuum state and contain a small amount of hydrogen, and its pressure is less than 1Pa. Therefore, when the elastic wave propagates from the anchor point to the second cavity, its propagation medium changes, so that the gas can suppress the loss of the elastic wave propagating upward, thereby reducing the energy lost from the anchor point, that is, improving the anchor point loss.

[0028] In another possible implementation, a first cavity is provided on the substrate, and a second cavity is provided on the cover structure. The gas in the first cavity can suppress the loss of elastic waves propagating downward, and the gas in the second cavity can suppress the loss of elastic waves propagating upward, thereby improving the anchor loss.

[0029] In some possible implementations, after the step of making a covering structure on the resonator, the manufacturing method further includes: thinning the substrate from the side of the substrate away from the first insulating layer; etching the first cavity on the side of the thinned substrate away from the first insulating layer. In this way, on the one hand, when the first insulating layer, the resonator, the second insulating layer and the covering structure are made on the substrate, the thickness of the substrate is relatively thick, thereby improving the processability of the substrate and avoiding damage when the first insulating layer, the resonator or the covering structure are made on the substrate due to the thin substrate. On the other hand, after the substrate is thinned, etching the first cavity on the substrate can make the distance between the cavity surface of the first cavity close to the first insulating layer and the first insulating layer closer, thereby reducing the propagation path of the elastic wave on the thickness of the substrate, thereby reducing the loss of the elastic wave. On the other hand, since the surface of the substrate facing the first insulating layer can provide sufficient support for the first insulating layer, the size of the first cavity can be set to be larger, thereby improving the suppression of the loss of the elastic wave.

[0030] In some possible implementations, after the step of etching the first cavity on the substrate, the manufacturing method further includes: providing a carrier; fixing the carrier to the side of the substrate away from the first insulating layer, and the carrier covers the first cavity. In this way, on the one hand, the carrier can increase the thickness of the entire MEMS resonant device, thereby improving the mechanical strength of the MEMS resonant device and reducing the situation where the MEMS resonant device is damaged by a large force during use. On the other hand, the carrier is arranged on the side of the substrate away from the first insulating layer and covers the first cavity, so that after the MEMS resonant device is packaged, the first cavity can be a sealed space. The sealed space can be a high vacuum space, which is conducive to better suppressing anchor point loss.

[0031] In a third aspect of the present application, a MEMS device is provided, comprising a circuit and a MEMS resonant device according to any embodiment of the first aspect or a MEMS resonant device manufactured by a manufacturing method according to any embodiment of the second aspect, wherein the MEMS resonant device is electrically connected to the circuit. The MEMS device can achieve all the effects of the MEMS resonant device.

[0032] In a fourth aspect of the present application, an electronic device is provided, comprising a circuit board and the MEMS device of the third aspect, wherein the MEMS device is electrically connected to the circuit board. The electronic device can achieve all the effects of the MEMS device. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0034] Figure 1 It is a structural schematic diagram of a MEMS resonant device in the related art;

[0035] Figure 2a This is a structural schematic diagram of a MEMS resonant device in the first embodiment of the present application;

[0036] Figure 2b for Figure 2a Cross-sectional view at AA in the middle;

[0037] Figure 2c for Figure 2a Cross-sectional view at BB in the middle;

[0038] Figure 3 This is a structural schematic diagram of a MEMS resonant device in a second embodiment of the present application;

[0039] Figure 4 This is a schematic structural diagram of a MEMS resonant device in a third embodiment of the present application;

[0040] Figure 5 This is a schematic structural diagram of a MEMS resonant device in a fourth embodiment of the present application;

[0041] Figure 6 This is a schematic diagram of the structure of a MEMS resonant device in a fifth embodiment of the present application;

[0042] Figure 7 This is a structural schematic diagram of a MEMS resonant device in a sixth embodiment of the present application;

[0043] Figure 8 This is a structural schematic diagram of a MEMS resonant device in a seventh embodiment of the present application;

[0044] Fig. 9 for Figure 5 A schematic diagram of a manufacturing method of a MEMS resonant device shown;

[0045] Fig.10a for Fig. 9 A schematic diagram of the manufacturing process of the first part of the steps in the manufacturing method shown;

[0046] Fig.10b for Fig. 9 A schematic diagram of the manufacturing process of the second part of the steps in the manufacturing method shown;

[0047] Fig.10c for Fig. 9 A schematic diagram of the manufacturing process of the third step in the manufacturing method shown;

[0048] Fig.11 for Figure 6 A schematic diagram of a manufacturing method of a MEMS resonant device shown;

[0049] Fig.12 for Fig. 9 A schematic diagram of the manufacturing process of step S201 in the manufacturing method shown;

[0050] Fig.13 for Figure 4 A schematic diagram of a manufacturing method of a MEMS resonant device shown;

[0051] Fig.14a for Fig.13 A schematic diagram of the manufacturing process of the first part of the steps in the manufacturing method shown;

[0052] Fig.14b for Fig.13 A schematic diagram of the manufacturing process of the second part of the steps in the manufacturing method shown;

[0053] Fig.15 for Figure 7 A schematic diagram of a manufacturing method of a MEMS resonant device shown;

[0054] Fig.16a for Fig.15 A schematic diagram of the manufacturing process of the first part of the steps in the manufacturing method shown;

[0055] Fig.16b for Fig.15 A schematic diagram of the production process of the second part of the steps in the production method shown.

[0056] Icon: 1-MEMS resonant device; 10-substrate; 11-first cavity; 12-elastic wave; 115-cavity surface; 300-first sacrificial layer; 30-first insulating layer; 31-first sub-insulating layer; 32-second sub-insulating layer; 33-third sub-insulating layer; 34-fourth sub-insulating layer; 500-resonator layer; 50-resonator; 51-oscillator; 52-anchor point; 521-third cavity; 53-connecting structure; 54-first gap; 55-second gap; 56-third gap; 70-covering structure; 71-second insulating layer Insulation layer; 710-second sacrificial layer; 711-fifth sub-insulating layer; 712-sixth sub-insulating layer; 713-hollow area; 72-first polysilicon layer; 721-support part; 722-body layer; 723-fourth cavity; 724-fifth cavity; 725-first release hole; 73-polysilicon cover; 74-passivation layer; 75-metal electrode; 76-electrical connection part; 77-second cavity; 781-second polysilicon layer; 782-third polysilicon layer; 783-second release hole; 79-third sacrificial layer; 80-carrier. DETAILED DESCRIPTION

[0057] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0058] The term "and / or" herein is merely a description of the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B may represent: A exists alone, A and B exist at the same time, and B exists alone, wherein A and B may be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one (item)" refers to one or more, and "plurality" refers to two or more. "At least one of the following (items)" or similar expressions refers to any combination of these items, including any combination of single (items) or plural (items). For example, at least one (item) of a, b or c may represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", wherein a, b, c may be single or multiple.

[0059] The terms "first" and "second" in the description and claims of the embodiments of the present application are used to distinguish different objects rather than to describe a specific order of objects. For example, a first target object and a second target object are used to distinguish different target objects rather than to describe a specific order of target objects.

[0060] "Connected", "connected" and similar words are used to express the intercommunication or interaction between different components, which may include direct connection or indirect connection through other components. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, inclusion of a series of steps or units. Methods, systems, products or devices are not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. "Up", "down", "left", "right" and the like are only used relative to the orientation of the components in the drawings. These directional terms are relative concepts. They are used for description and clarification relative to the description, which may change accordingly according to the change of the orientation of the components in the drawings.

[0061] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0062] In the description of the embodiments of the present application, unless otherwise specified, the meaning of "multiple" refers to two or more than two. For example, multiple processing units refer to two or more processing units; multiple systems refer to two or more systems.

[0063] Electronic devices such as mobile phones, electronic watches, televisions, etc., may generally include a MEMS device, a processor, and a circuit board electrically connected to the MEMS device. The processor is electrically connected to the MEMS device.

[0064] The MEMS device may specifically be a resonator, a clock device, a crystal oscillator, or a gyroscope. The MEMS device may include a MEMS resonant device and a circuit, and the MEMS resonant device is electrically connected to the circuit. Exemplarily, when the MEMS device is a clock device, the clock device may include a MEMS resonant device and a holding circuit. The holding circuit provides an oscillation excitation to the MEMS resonant device, and the MEMS resonant device generates a clock signal after receiving the oscillation excitation. The clock device may send the clock signal to the processor, and the processor performs calculations based on the clock signal.

[0065] like Figure 1As shown, the MEMS resonator device 1 may include a stacked substrate 10, a first insulating layer 30, a resonator 50 and a covering structure 70. The resonator 50 includes a vibrator 51 and an anchor 52 connected to the vibrator 51. The anchor 52 is fixed between the first insulating layer 30 and the covering structure 70, a portion of the vibrator 51 is fixed on the anchor 52, and a portion of the vibrator 51 is suspended. External excitation can be loaded on the vibrator 51, and the vibrator 51 will generate an elastic wave 12, which propagates toward the anchor 52 along the connection structure between the vibrator 51 and the anchor 52. The elastic wave 12 propagating to the anchor 52 will propagate toward the covering structure 70 above the anchor 52, and the elastic wave 12 may also propagate toward the substrate 10 below the anchor 52, and the elastic wave 12 may also propagate toward the anchor 52 away from the vibrator 51. The elastic wave 12 propagating to the covering structure 70 will be absorbed by the covering structure 70, the elastic wave 12 propagating to the substrate 10 will be absorbed by the substrate 10, and the elastic wave 12 propagating to the anchor point 52 away from the vibrator 51 will propagate outside the vibrator 51 through the anchor point 52. The propagation of these elastic waves 12 will cause energy loss of the vibrator 51, which can be called anchor point loss. As a result, the energy loss of the MEMS resonant device 1 will be large, resulting in a low Q value.

[0066] In the related art, the anchor loss is mainly improved by suppressing the propagation of elastic waves. However, the improvement effect on the anchor loss is not good, resulting in the Q value of the MEMS resonant device 1 being still low.

[0067] Based on this, an embodiment of the present application provides a MEMS resonance device 1 that can improve anchor point loss.

[0068] For the convenience of description, three directions can be defined, namely, a first direction (X direction), a second direction (Y direction), and a third direction (Z direction). The X direction represents the length direction of the MEMS resonant device 1, the Y direction represents the width direction of the MEMS resonant device 1, and the Z direction represents the thickness direction of the MEMS resonant device 1. The X direction, the Y direction, and the Z direction are perpendicular to each other.

[0069] Moreover, in the embodiment of the present application, “above” and “below” are both directions determined by taking the substrate 10 as the bottom of the MEMS resonant device 1 .

[0070] like Figure 2a As shown, an embodiment of the present application provides a MEMS resonance device 1, comprising: a substrate 10, a first insulating layer 30, a resonator 50 and a covering structure 70 which are stacked in sequence.

[0071] Reference Figure 2bThe resonator 50 may include an anchor point 52, an oscillator 51 and a connection structure 53. The number of the anchor points 52 may be two, and the two anchor points 52 are respectively located on both sides of the oscillator 51. Each anchor point 52 is connected to the oscillator 51 through the connection structure 53. Figure 2a As shown, the upper surface of the anchor 52 contacts the cover structure 70 , and the lower surface of the anchor 52 contacts the first insulating layer 30 , so that the anchor 52 can be fixed between the cover structure 70 and the first insulating layer 30 .

[0072] like Figure 2a As shown, the vibrator 51 and the anchor point 52 are arranged in the same layer and can have the same thickness. Exemplarily, the thickness of the vibrator 51 and the anchor point 52 can be an integral multiple of the wavelength of the elastic wave.

[0073] like Figure 2a As shown, the two ends of the vibrator 51 are fixed to two anchor points 52 through two connecting structures 53 respectively. The vibrator 51 is located between the covering structure 70 and the substrate 10. There is a gap between the vibrator 51 and the covering structure 70, and there is also a gap between the vibrator 51 and the substrate 10, so that the vibrator 51 can oscillate under the action of external excitation. When the vibrator 51 oscillates, elastic waves will be generated, and part of the elastic waves can be transmitted to the anchor points 52 through the connecting structure 53.

[0074] like Figure 2a As shown, the anchor point 52 is provided with a third cavity 521, and the third cavity 521 penetrates from the surface of the anchor point 52 toward the first insulating layer 30 to the surface of the anchor point 52 toward the second insulating layer 71. That is, the third cavity 521 penetrates from the upper surface of the anchor point 52 to the lower surface. After the elastic wave propagates to the anchor point 52, it will propagate in the direction of the anchor point 52 away from the vibrator 51, for example, the elastic wave propagates in the direction pointed by the X direction, or the elastic wave propagates in the direction opposite to the pointing direction of the X direction. Since the third cavity 521 is provided on the anchor point 52, and the third cavity 521 can be in a high vacuum state and contain a small amount of hydrogen (H2), the pressure of which is less than 1Pa, therefore, when the elastic wave propagates from the anchor point to the third cavity, its propagation medium changes, thereby suppressing the loss of the elastic wave propagating in the direction of the anchor point 52 away from the vibrator 51.

[0075] like Figure 2aAs shown, the first insulating layer 30 includes a first sub-insulating layer 31, a second sub-insulating layer 32, a third sub-insulating layer 33 and a fourth sub-insulating layer 34 arranged along the X direction. The first sub-insulating layer 31 and the second sub-insulating layer 32 are located below the anchor point 52a, that is, the projections of the first sub-insulating layer 31 and the second sub-insulating layer 32 on the resonator 50 are both located within the range of the anchor point 52a. A first gap 54 is formed between the first sub-insulating layer 31 and the second sub-insulating layer 32, and the first gap 54 is connected to the third cavity 521 of the anchor point 52a. Exemplarily, the projection of the first gap 54 on the resonator 50 covers the third cavity 521.

[0076] like Figure 2a As shown, the third sub-insulating layer 33 and the fourth sub-insulating layer 34 are located below another anchor point 52b, that is, the projections of the third sub-insulating layer 33 and the fourth sub-insulating layer 34 on the resonator 50 are both located within the range of the anchor point 52b. A second gap 55 is formed between the third sub-insulating layer 33 and the fourth sub-insulating layer 34, and the second gap 55 is connected to the third cavity 521 of the anchor point 52b. Exemplarily, the projection of the second gap 55 on the resonator 50 covers the third cavity 521.

[0077] like Figure 2a As shown, a third gap 56 is formed between the second sub-insulating layer 32 and the third sub-insulating layer 33. The projection of the third gap 56 on the resonator 50 covers the vibrator 51, so that when the vibrator 51 is externally excited, the third gap 56 can provide a space for the vibrator 51 to oscillate downward. The thickness of the first insulating layer 30 along the Z direction can be 1um-100um, and the thickness of the third gap 56 along the Z direction can be 1um-100um.

[0078] In this embodiment, the substrate 10 may be a silicon Si substrate, a germanium Ge substrate, or a SiGe substrate. The substrate 10 may also be a substrate 10 including other elements or a substrate 10 of other compounds, such as GaAs, InP, or SiC.

[0079] like Figure 2aAs shown, a first cavity 11 is provided on the substrate 10, and the projection of the first cavity 11 on the resonator 50 overlaps with the anchor point 52. The number of the first cavities 11 can be the same as the number of the anchor points 52. For example, when the number of the anchor points 52 is two, the number of the first cavities 11 can also be two. And the projection of each first cavity 11 on the resonator 50 overlaps with each anchor point 52 correspondingly. After the elastic wave propagates to the anchor point 52, it will also propagate toward the bottom of the anchor point 52. Since the substrate 10, the first insulating layer 30, the resonator 50, the second insulating layer 71 and the covering structure 70 are stacked, the substrate 10 is arranged below the resonator 50. Moreover, the projection of the first cavity 11 provided on the substrate 10 on the resonator 50 overlaps with the anchor point 52, that is, the first cavity 11 is located below the anchor point 52. Therefore, when the elastic wave propagating to the anchor point 52 propagates toward the bottom of the anchor point 52, the elastic wave will propagate to the first cavity 11. The first cavity 11 is usually filled with gas, and the propagation energy of elastic waves in the gas medium is much smaller than that in the solid medium. When the elastic wave propagates from the anchor point 52 to the first cavity 11, its propagation medium changes from solid medium to gas medium. The heterogeneous propagation medium can suppress the loss of the elastic wave propagating downward, thereby reducing the energy lost from the anchor point 52, that is, improving the anchor point loss.

[0080] In addition, if Figure 2a As shown, the projection of the cavity surface 115 of the first cavity 11 close to the first insulating layer 30 on the resonator 50 overlaps with the first part of the anchor points. The first part of the anchor point can be the part of the anchor point 52 between one end of the anchor point 52 facing the vibrator 51 and the third cavity surface 115. After the elastic wave propagating from the vibrator 51 is transmitted from one end of the anchor point 52 to the anchor point 52, it can propagate downward from the anchor point 52. The first cavity 11 is located below the first part of the anchor point, thereby suppressing the loss of the elastic wave propagating downward. It can be seen that the first cavity 11 located below the anchor point 52, the second cavity 77 located above the anchor point 52, and the third cavity 521 located on the anchor point 52 can suppress the loss of the elastic wave in three directions respectively, thereby further improving the anchor point loss.

[0081] like Figure 2aAs shown, the dimension H1 of the first cavity 11 along the Z direction is smaller than the thickness H2 of the substrate 10, and the first cavity 11 is disposed on the side of the substrate 10 away from the first insulating layer 30. That is, there is a gap between the cavity surface 115 of the first cavity 11 close to the first insulating layer 30 and the surface of the substrate 10 facing the first insulating layer 30. In this way, on the one hand, the surface of the substrate 10 facing the first insulating layer 30 is a complete surface, that is, a surface without any cavity. In other words, the surface of the substrate 10 in contact with the first insulating layer 30 is a complete surface, thereby enabling the substrate 10 to provide sufficient support for the first insulating layer 30. On the other hand, when manufacturing the MEMS resonant device 1, the first insulating layer 30, the resonator 50, the second insulating layer 71 and the covering structure 70 can be sequentially manufactured on the substrate 10 without etching the first cavity 11. Next, a first cavity 11 is etched on the surface of the substrate 10 facing away from the first insulating layer 30. Since the surface of the substrate 10 facing the first insulating layer 30 can provide sufficient support for the first insulating layer 30, the size of the first cavity 11 can be set to a larger size, thereby improving the suppression of elastic wave losses.

[0082] like Figure 2a As shown, the dimension L1 of the end of the first cavity 11 away from the first insulating layer 30 along the X direction is greater than the dimension L2 of the end of the first cavity 11 close to the first insulating layer 30 along the X direction. In other words, the dimension L1 of the cavity opening of the first cavity 11 along the X direction is greater than the dimension L2 of the bottom of the first cavity 11 along the X direction. Since the first cavity 11 is formed by etching the surface of the substrate 10 away from the first insulating layer 30 after the first insulating layer 30, the resonator 50, the second insulating layer 71 and the covering structure 70 are manufactured, the first cavity 11 can be etched by a wet etching process, thereby reducing the processing cost.

[0083] like Figure 2a As shown, the projection of the cavity surface 115 of one of the first cavities 11a close to the first insulating layer 30 on the first insulating layer 30 covers the second sub-insulating layer 32. The elastic wave propagating to the anchor point 52 can propagate to the third cavity 521 along the direction away from the vibrator 51 on the anchor point 52. Since the first gap 54 is connected to the third cavity 521, the elastic wave propagating downward will propagate to the substrate 10 through the second sub-insulating layer 32. Since the projection of the cavity surface 115 of the first cavity 11 close to the first insulating layer 30 on the first insulating layer 30 covers the second sub-insulating layer 32, it can be seen that the area of ​​the cavity surface 115 of the first cavity 11 close to the first insulating layer 30 is larger than the surface area of ​​the second sub-insulating layer 32, thereby the elastic wave propagating from the second sub-insulating layer 32 can be well suppressed. It can be understood that the projection of the cavity surface 115 of another first cavity 11 close to the first insulating layer 30 on the first insulating layer 30 can cover the third sub-insulating layer 33.

[0084] like Figure 2a As shown, the covering structure 70 includes a second insulating layer 71, a first polysilicon layer 72, a polysilicon upper cover 73, a passivation layer 74, and a metal electrode 75 stacked on the side of the resonator 50 facing away from the substrate 10. The covering structure 70 also includes an electrical connection portion 76, which is penetrated by the first polysilicon layer 72 and the polysilicon upper cover 73.

[0085] like Figure 2a As shown, a hollow region 713 is formed on the second insulating layer 71. Exemplarily, the second insulating layer 71 includes a fifth sub-insulating layer 711 and a sixth sub-insulating layer 712 arranged and spaced along the X direction. A hollow region 713 is formed between the fifth sub-insulating layer 711 and the sixth sub-insulating layer 712. The hollow region 713 runs through from the lower surface to the upper surface of the second insulating layer 71.

[0086] The electrical connection portion 76 contacts the anchor point 52, thereby achieving electrical connection between the electrical connection portion 76 and the anchor point 52. There is a gap between the electrical connection portion 76 and the first polysilicon layer 72, and there is also a gap between the electrical connection portion 76 and the polysilicon upper cover 73 to avoid leakage. The projection of the electrical connection portion 76 on the resonator 50 is located within the range of the anchor point 52. The number of electrical connection portions 76 can be at least two, for example, Figure 2c As shown, in this embodiment, there are two electrical connection parts 76, which are arranged opposite to each other, and the projections of the two electrical connection parts 76 on the resonator 50 are respectively located on both sides of the vibrator 51. The two electrical connection parts 76 can enclose a first area, which is Figure 2c The projection of the first region on the resonator 50 covers the vibrator 51 and part of the anchor point 52. The material of the electrical connection portion 76 can be doped polysilicon.

[0087] like Figure 2a As shown, the first polysilicon layer 72 includes a support portion 721 and a body layer 722. The number of the support portions 721 can be two, and both of the two support portions 721 are located in the hollow area 713, and one end is fixed on the anchor point 52. The thickness of the support portion 721 along the Z direction is the same as the thickness of the hollow area 713, that is, the upper surface of the support portion 721 is flush with the upper surface of the second insulating layer 71. The body layer 722 is fixed to the other end of the two support portions 721, and is also fixed to the side of the second insulating layer 71 away from the resonator 50. The cross-sectional shape of the support portion 721 taken along the surface perpendicular to the Z direction is annular, specifically, a circular ring. In this way, a second cavity 77 can be formed inside the support portion 721, and the second cavity 77 can be understood as being provided on the side surface of the covering structure 70 facing the resonator 50.

[0088] like Figure 2aAs shown, the second cavity 77 is located in the first region, that is, the projection of the second cavity 77 on the resonator 50 is closer to the vibrator 51 than the projection of the electrical connection portion 76 on the resonator 50, the projection of the second cavity 77 on the resonator 50 overlaps with the anchor point 52, and the projection of the second cavity 77 on the resonator 50 does not overlap with the vibrator 51. After the elastic wave propagates to the anchor point 52, it will also propagate toward the top of the anchor point 52. Since the substrate 10, the first insulating layer 30, the resonator 50, the second insulating layer 71 and the covering structure 70 are stacked, the covering structure 70 is arranged above the resonator 50. Moreover, the projection of the second cavity 77 provided on the covering structure 70 on the resonator 50 overlaps with the anchor point 52, that is, the second cavity 77 is located above the anchor point 52, so when the elastic wave propagating to the anchor point 52 propagates upward from the anchor point 52, the elastic wave will propagate to the second cavity 77, and the second cavity 77 can be in a high vacuum state and contain a small amount of H2, and its pressure is less than 1 Pa. Therefore, when the elastic wave propagates from the anchor point 52 to the second cavity 77, its propagation medium changes, thereby suppressing the loss of the elastic wave propagating upward, thereby reducing the energy lost from the anchor point 52, that is, improving the anchor point loss.

[0089] Moreover, if Figure 2a As shown, the projection of the second cavity 77 on the anchor point 52 does not overlap with the third cavity 521, and the third cavity 521 is farther away from the vibrator 51 than the projection of the second cavity 77 on the resonator 50. That is, the second cavity 77 is closer to the vibrator 51 than the third cavity 521. After the elastic wave propagating from the vibrator 51 is transmitted from the anchor point 52 toward the first end of the vibrator 51 to the anchor point 52, it can propagate upward from the anchor point 52. Since the second cavity 77 is closer to the vibrator 51, the second cavity 77 can well suppress the loss of the elastic wave propagating upward.

[0090] In addition, if Figure 2a As shown, the projection of the second cavity 77 on the substrate 10 overlaps with the first cavity 11. And the area of ​​the overlapping region accounts for more than 1% of the projection area of ​​the second cavity 77. The dimensions of the first cavity 11 and the second cavity 77 along the Z direction are both related to the wavelength of the elastic wave. Exemplarily, the dimensions of the first cavity 11 and the second cavity 77 along the Z direction can be an integer N times the wavelength of the elastic wave. And N can be greater than 10.

[0091] like Figure 2aAs shown, a fourth cavity 723 can be formed between the two support portions 721, and the fourth cavity 723 can be understood as being arranged on the side of the covering structure 70 facing the resonator 50. Also, because both support portions 721 are located in the hollow area 713, the second cavity 77 and the fourth cavity 723 are both part of the hollow area 713. It can also be said that the two support portions 721 separate the hollow area 713 to form two second cavities 77 and a fourth cavity 723. The projection of the fourth cavity 723 on the resonator 50 covers part of the anchor point 52 and the vibrator 51. Since the second cavity 77 is formed by the inside of the support portion 721 and the fourth cavity 723 is formed by the two support portions 721, the fourth cavity 723 is in the same layer as the second cavity 77 and is arranged at intervals. In this way, the supporting effect on other components of the covering structure 70 except the support portion 721 can be improved. The dimensions of the fourth cavity 723 and the second cavity 77 along the Z direction are both 1un-400um.

[0092] A fifth cavity 724 may be formed between the support portion 721 and the fifth sub-insulating layer 711 , and the fifth cavity 724 is connected to the third cavity 521 , so that the third cavity 521 can be easily etched.

[0093] In other embodiments of the present application, Figure 3 As shown, Figure 2a The difference between the illustrated embodiments lies in the structure of the substrate 10. Specifically, in the present embodiment, the first cavity 11 is not provided on the substrate 10. It is understood that when most of the elastic waves generated by the vibrator 51 propagate along the anchor point 52 and above the anchor point 52, and the proportion of the elastic waves propagating below the anchor point 52 is small, the first cavity 11 may not be provided on the substrate 10.

[0094] In this embodiment, a third cavity 521 is provided on the anchor point 52, and a second cavity 77 is provided on the covering structure 70. Therefore, this embodiment can suppress the loss of elastic waves propagating in the direction away from the vibrator 51 along the anchor point 52 and the loss of elastic waves propagating toward the top of the anchor point 52.

[0095] In other embodiments of the present application, Figure 4 As shown, Figure 2a The difference between the embodiments shown is the covering structure 70. Specifically, in this embodiment, the second cavity 77 is not provided on the covering structure 70. Figure 4 As shown, two fifth cavities 724 and a fourth cavity 723 are provided on the second insulating layer 71. And the support portion 721 is provided inside the second insulating layer 71. It can be understood that when most of the elastic waves generated by the vibrator 51 propagate along the anchor point 52 and toward the bottom of the anchor point 52, and the proportion of the elastic waves propagating toward the top of the anchor point 52 is small, the second cavity 77 may not be provided on the covering structure 70.

[0096] In this embodiment, a third cavity 521 is provided on the anchor point 52 and a first cavity 11 is provided on the substrate 10 , which can suppress the loss of elastic waves propagating in a direction away from the oscillator 51 along the anchor point 52 and the loss of elastic waves propagating toward the bottom of the anchor point 52 .

[0097] In other embodiments of the present application, Figure 5 As shown, Figure 2a The difference between the embodiments shown is that Figure 2a The embodiment shown in the figure adds a carrier sheet 80. Figure 5 As shown, the MEMS resonant device 1 further includes a carrier 80, which is disposed on the side of the substrate 10 away from the first insulating layer 30, and the carrier 80 covers the first cavity 11. In this way, on the one hand, the carrier 80 can increase the thickness of the entire MEMS resonant device 1, thereby improving the mechanical strength of the MEMS resonant device 1 and reducing the situation where the MEMS resonant device 1 is damaged by a large force during use. On the other hand, the carrier 80 is disposed on the side of the substrate 10 away from the first insulating layer 30 and covers the first cavity 11, so that after the MEMS resonant device 1 is packaged, the first cavity 11 can form a sealed space. The sealed space can be a high vacuum space, which is conducive to better suppressing the anchor loss.

[0098] In other embodiments of the present application, Figure 6 As shown, Figure 2a The difference between the embodiments shown is the location of the first cavity 11. Figure 6 As shown, the first cavity 11 is arranged on the side of the substrate 10 facing the first insulating layer 30. Moreover, the projection of the first cavity 11 on the second sub-insulating layer 32 is located within the range of the second sub-insulating layer 32. The size of the first cavity 11 along the Z direction is smaller than the size of the substrate 10 along the Z direction. In this way, after the MEMS resonant device is packaged, the first cavity 11 can be a sealed space, and the sealed space can also be a sealed space with a high vacuum degree, thereby further improving the suppression effect of the first cavity 11 on elastic waves. Moreover, the projection of the first cavity 11 on the first insulating layer 30 is located within the range of the second sub-insulating layer 32. In this way, there is a partial area at the position where the substrate 10 contacts the second sub-insulating layer 32 where the first cavity 11 is not arranged, and this partial area can provide support for the second sub-insulating layer 32.

[0099] It can be understood that, in other embodiments, the size of the first cavity 11 along the Z direction may also be the same as the size of the substrate 10 along the Z direction, that is, the first cavity 11 penetrates from the side of the substrate 10 facing the first insulating layer 30 to the side of the substrate 10 facing away from the first insulating layer 30. In other words, the first cavity 11 penetrates from the lower surface of the substrate 10 to the upper surface.

[0100] In other embodiments of the present application, Figure 7 As shown, Figure 2a The difference between the embodiments shown is the structure of the covering structure 70 and the location of the second cavity 77. Figure 7 As shown, the covering structure 70 includes a second polysilicon layer 781, a third polysilicon layer 782, a polysilicon cover 73, a passivation layer 74 and a metal electrode 75 stacked on the resonator 50. The electrical connection portion 76 of the covering structure 70 is provided through the first polysilicon layer 72, the second polysilicon 781, the third polysilicon 785 and the polysilicon cover 73.

[0101] like Figure 7 As shown, the second cavity 77 is located inside the covering structure 70, and there is a distance between the cavity surface 115 of the second cavity 77 close to the resonator 50 and the surface of the covering structure 70 facing the resonator 50. Exemplarily, the second cavity 77 is provided on the second polysilicon layer 781, and the second cavity 77 runs through from the lower surface to the upper surface of the second polysilicon layer 781. In this way, only the fourth cavity 723 can be provided on the surface of the covering structure 70 facing the second insulating layer 71, and no other cavities are required. Thereby, the contact area between the covering structure 70 and the second insulating layer 71 can be increased, thereby increasing the support strength of the second insulating layer 71 to the covering structure 70. Therefore, the embodiment of the present application can increase the support strength of the second insulating layer 71 to the covering structure 70 while suppressing the loss of elastic waves.

[0102] In other embodiments of the present application, Figure 8 As shown, Figure 2a The difference between the embodiments shown is the relationship between the second cavity 77 and the fourth cavity 723 and the structure of the support portion 721. In this embodiment, Figure 8 As shown, the fourth cavity 723 is arranged in the same layer as the second cavity 77 and is connected. The cross-sectional shape of the support portion 721 taken along the surface perpendicular to the Z direction can be a semicircular ring. That is to say, the hollow area 713 formed between the fifth sub-insulating layer 711 and the sixth sub-insulating layer 712 is divided into three cavities by two support portions 721, and these three cavities are respectively two fifth cavities 724, the second cavity 77 and a larger cavity formed by the connection of the fourth cavity 723. In this way, the fourth cavity 723 can provide a evacuation space for the vibration of the vibrator 51, and the second cavity 77 can suppress the loss of elastic waves propagating toward the top of the anchor point 52. When the fourth cavity 723 is arranged in the same layer as the second cavity 77 and is connected, the projection of the connected second cavity 77 and the fourth cavity 723 on the resonator 50 can be increased, and the overlapping area with the anchor point 52 can be increased, thereby further improving the suppression of the loss of elastic waves.

[0103] The present application also provides a method for manufacturing a MEMS resonant device 1. The method can be applied to Figure 5 The MEMS resonant device 1 shown. Fig. 9 As shown, the production method may include:

[0104] S101, providing a silicon on insulator (SOI) wafer.

[0105] Among them, Fig.10a As shown, SOI may include a stacked substrate 10, a first sacrificial layer 300 and a resonant body layer 500. The substrate 10 may be a silicon Si substrate, a germanium Ge substrate, or a SiGe substrate. The substrate 10 may also be a substrate 10 including other elements or a substrate 10 of other compounds, such as GaAs, InP, or SiC. The first sacrificial layer 300 may be an oxide layer. The resonant body layer 500 may be a silicon layer.

[0106] S102 , etching the resonator layer 500 to form the resonator 50 .

[0107] like Fig.10a As shown, the resonator 50 includes a vibrator 51 and an anchor point 52 which are arranged in the same layer and connected, and a connection structure 53 connected between the vibrator 51 and the anchor point 52. The number of the anchor points 52 can be two, and the two anchor points 52 are respectively located on both sides of the vibrator 51. Each anchor point 52 is connected to the vibrator 51 through a connection. A third cavity 521 is formed on each anchor point 52.

[0108] S103 , forming a second sacrificial layer 710 on the resonator 50 .

[0109] The second sacrificial layer 710 may be an oxide layer. Fig.10a As shown, the second sacrificial layer 710 may include a plurality of sub-sacrificial layers arranged and spaced along the X direction. Exemplarily, in this embodiment, the number of sub-sacrificial layers may be five. In other embodiments, the number of sub-sacrificial layers may also be less than five, or greater than five. There is a gap between each two adjacent sub-sacrificial layers.

[0110] S104 , forming a first polysilicon layer 72 on the second sacrificial layer 710 .

[0111] like Fig.10a As shown, the first polysilicon layer 72 may include a body layer 722 and a support portion 721. Since there is a gap between each two adjacent sub-sacrificial layers, when the first polysilicon layer 72 is manufactured, part of the first polysilicon layer 72 may be deposited into the gap, and the part of the first polysilicon layer 72 may be referred to as the support portion 721. For example, Fig.10aThe cross section of the support portion 721 shown in FIG. 7 may be annular. The portion of the first polysilicon layer 72 located on the second sacrificial layer 710 may be referred to as a body layer 722 .

[0112] S105 , forming a first release hole 725 on the first polysilicon layer 72 .

[0113] like Fig.10a As shown, there may be a plurality of first release holes 725 , and one or more first release holes 725 are disposed above each sub-sacrificial layer.

[0114] S106 , etching the first sacrificial layer 300 and the second sacrificial layer 710 respectively to form a first insulating layer 30 and a second insulating layer 71 .

[0115] like Fig.10b As shown, the first sacrificial layer 300 and the second sacrificial layer 710 can be etched through the first release hole 725. A first gap 54, a second gap 55, and a third gap 56 are formed on the first insulating layer 30. The first gap 54 is connected to the third cavity 521 of one of the anchor points 52. The second gap 55 is connected to the third cavity 521 of the other anchor point 52. The projection of the third gap 56 on the resonator 50 covers the vibrator 51.

[0116] like Fig.10b As shown, a second cavity 77 and a fourth cavity 723 are formed on the second insulating layer 71. The number of the second cavity 77 can be two. The projection of the fourth cavity 723 on the resonator 50 covers part of the anchor point 52 and the vibrator 51. The projection of the second cavity 77 on the resonator 50 overlaps with the anchor point 52 and is located within the range of the anchor point 52.

[0117] S107, such as Fig.10b As shown, a polysilicon cap 73 is formed on the first polysilicon layer 72 .

[0118] S108, such as Fig.10b As shown, an electrical connection portion 76 is made on the polysilicon upper cover 73. The electrical connection portion 76 can penetrate from the polysilicon upper cover 73 to the first polysilicon layer 72. The electrical connection portion 76 contacts the anchor point 52 through the support portion 721 to achieve electrical connection with the anchor point 52.

[0119] S109, such as Fig.10b As shown, a passivation layer 74 is formed on the polysilicon upper cover 73 .

[0120] The passivation layer 74 may include a plurality of spaced sub-passivation layers. A complete passivation layer may be first formed on the polysilicon upper cover 73, and then the complete passivation layer is etched to form a plurality of spaced sub-passivation layers, which are spaced and arranged above the electrical connection portion 76.

[0121] S110 , forming a metal electrode 75 on the passivation layer 74 .

[0122] like Fig.10c As shown, the metal electrode 75 is located above the electrical connection portion 76 , so that part of the metal electrode 75 will be deposited in the gap between the passivation layer 74 and the other part of the metal electrode 75 will be deposited above the passivation layer 74 .

[0123] S111, such as Fig.10c As shown, the substrate 10 is thinned from the side of the substrate 10 facing away from the first insulating layer 30 .

[0124] In this embodiment, the substrate 10 may be thinned using a grinding wheel.

[0125] S112 , etching a first cavity 11 on a side of the thinned substrate 10 facing away from the first insulating layer 30 .

[0126] like Fig.10c As shown, the projection of the first cavity 11 on the resonator 50 overlaps with the anchor point 52. Thus, on the one hand, when the first insulating layer 30, the resonator 50, the second insulating layer 71 and the covering structure 70 are made on the substrate 10, the thickness of the substrate 10 is relatively thick, thereby improving the processability of the substrate 10 and avoiding damage when the first insulating layer 30, the resonator 50 or the covering structure 70 are made on the substrate 10 due to the thinness of the substrate 10. On the other hand, after the substrate 10 is thinned, the first cavity 11 is etched on the substrate 10, so that the distance between the cavity surface 115 of the first cavity 11 close to the first insulating layer 30 and the first insulating layer 30 is relatively close, thereby reducing the propagation path of the elastic wave on the thickness of the substrate 10, thereby reducing the loss of the elastic wave. On the other hand, since the surface of the substrate 10 facing the first insulating layer 30 can provide sufficient support for the first insulating layer 30, the size of the first cavity 11 can be set to be larger, thereby improving the suppression of the loss of the elastic wave.

[0127] S113, such as Fig.10c As shown, a carrier sheet 80 is provided and fixed to a side of the substrate 10 facing away from the first insulating layer 30 , and the carrier sheet 80 covers the first cavity 11 .

[0128] The carrier 80 may be a wafer or a printed circuit board (PCB). When the carrier 80 is a wafer, the carrier 80 may be fixed to the side of the substrate 10 away from the first insulating layer 30 by bonding. When the carrier 80 is a PCB, the carrier 80 may be fixed to the side of the substrate 10 away from the first insulating layer 30 by laminating.

[0129] In this way, on the one hand, the carrier 80 can increase the thickness of the entire MEMS resonant device 1, thereby improving the mechanical strength of the MEMS resonant device 1 and reducing the situation where the MEMS resonant device 1 is damaged by a large force during use. On the other hand, the carrier 80 is fixed to the side of the substrate 10 away from the first insulating layer 30 by bonding, and covers the first cavity 11, so that the first cavity 11 can be a sealed space. Compared with the way in which the substrate 10 is bonded to the PCB board, the sealed space formed in this embodiment can be a high vacuum space, which is conducive to better suppressing the anchor loss.

[0130] Understandably, Fig. 9 , Fig.10a , Fig.10b and Fig.10c The production method shown is Figure 5 The method for manufacturing the MEMS resonant device 1 is directed to Figure 2a The MEM devices shown can be Fig. 9 Based on the above, the manufacturing method formed by removing step S113 is manufactured. Figure 5 The MEMS resonant device 1 shown can be used in Fig. 9 The method is produced by removing steps S111-S113 from the above. Figure 8 The MEMS resonant device 1 shown can be used in Fig. 9 The manufacturing method is formed by removing step S113 and changing the structure of the supporting portion 721 of the first polysilicon layer 72 when manufacturing the first polysilicon layer 72.

[0131] In other embodiments of the present application, a method for manufacturing a MEMS resonant device 1 is also provided, which is applied to Figure 6 In the embodiment shown. The manufacturing method of this embodiment is Fig. 9 The difference between the manufacturing methods shown is the manufacturing process of the first cavity 11. Fig.11 As shown, in this embodiment, the manufacturing method may include:

[0132] S201, providing a cavity-silicon on insulator (C-SOI) wafer containing a cavity.

[0133] like Fig.12As shown, C-SOI includes a stacked substrate 10, a first sacrificial layer 300 and a resonant body layer 500. A first cavity 11 is provided on the substrate 10. The first cavity 11 is provided on the side of the substrate 10 facing the first insulating layer 30. In this way, the elastic wave propagating downward from the anchor point 52 can propagate to the first cavity 11 after passing through the first sub-insulating layer 31, thereby reducing the situation where the elastic wave does not propagate along the substrate 10, and also can reduce the situation where the elastic wave propagates in more solid materials and causes large losses. Therefore, the suppression effect of the gas in the first cavity 11 on the elastic wave can be further improved.

[0134] S202 , etching the resonator layer 500 to form the resonator 50 .

[0135] Reference Fig.10a Step S102 is shown.

[0136] S203 , forming a second sacrificial layer 710 on the resonator 50 .

[0137] Reference Fig.10a Step S103 shown.

[0138] S204 , forming a first polysilicon layer 72 on the second sacrificial layer 710 .

[0139] Reference Fig.10a Step S104 is shown.

[0140] S205 , forming a first release hole 725 on the first polysilicon layer 72 .

[0141] Reference Fig.10a Step S105 shown.

[0142] S206 , etching the first sacrificial layer 300 and the second sacrificial layer 710 respectively to form a first insulating layer 30 and a second insulating layer 71 .

[0143] Reference Fig.10b Step S106 is shown.

[0144] S207 , forming a polysilicon upper cover 73 on the first polysilicon layer 72 .

[0145] Reference Fig.10b Step S107 shown.

[0146] S208 , making an electrical connection portion 76 on the polysilicon upper cover 73 .

[0147] Reference Fig.10b Step S108 is shown.

[0148] S209 , forming a passivation layer 74 on the polysilicon upper cover 73 .

[0149] Reference Fig.10b Step S109 shown.

[0150] S210 , forming a metal electrode 75 on the passivation layer 74 .

[0151] Reference Fig.10c Step S110 is shown.

[0152] S211 , thinning the substrate 10 from a side of the substrate 10 away from the first insulating layer 30 .

[0153] Reference Fig.10c Step S111 is shown.

[0154] In other embodiments of the present application, a method for manufacturing a MEMS resonant device 1 is also provided, which is applied to Figure 4 In the embodiment shown. Fig.13 As shown, in this embodiment, the manufacturing method includes:

[0155] S301, providing a silicon on insulator (SOI) wafer.

[0156] Reference Fig.10a Step S101 shown.

[0157] S302 , etching the resonator layer 500 to form the resonator 50 .

[0158] Reference Fig.10a Step S102 is shown.

[0159] S303 , forming a second sacrificial layer 710 on the resonator 50 .

[0160] like Fig.14a As shown, the second sacrificial layer 710 may be an oxide layer. The second sacrificial layer 710 may include a plurality of sub-sacrificial layers arranged and spaced along the X direction. The number of the sub-sacrificial layers may be three. There is a gap between each two adjacent sub-sacrificial layers.

[0161] S304 , forming a first polysilicon layer 72 on the second sacrificial layer 710 .

[0162] like Fig.14a As shown, the first polysilicon layer 72 may include a body layer 722 and a support portion 721. Since there is a gap between each two adjacent sub-sacrificial layers, when the first polysilicon layer 72 is manufactured, part of the first polysilicon layer 72 may be deposited into the gap, and the part of the first polysilicon layer 72 may be referred to as the support portion 721. The cross-sectional shape of the support portion 721 may be a solid circle. The part of the first polysilicon layer 72 located on the second sacrificial layer 710 may be referred to as the body layer 722.

[0163] S305 , forming a first release hole 725 on the first polysilicon layer 72 .

[0164] like Fig.14a As shown, the first release hole 725 is located above the second sacrificial layer 710 .

[0165] S306 , etching the first sacrificial layer 300 and the second sacrificial layer 710 respectively to form a first insulating layer 30 and a second insulating layer 71 .

[0166] like Fig.14b As shown, the first sacrificial layer 300 and the second sacrificial layer 710 may be etched through the first release hole 725 to form the first insulating layer 30 and the second insulating layer 71 .

[0167] S307, such as Fig.14b As shown, a polysilicon cap 73 is formed on the first polysilicon layer 72 .

[0168] S308, such as Fig.14b As shown, an electrical connection portion 76 is made on the polysilicon upper cover 73 .

[0169] S309 , forming a passivation layer 74 on the polysilicon upper cover 73 .

[0170] Reference Fig.10b Step S109 shown.

[0171] S310 , forming a metal electrode 75 on the passivation layer 74 .

[0172] Reference Fig.10c Step S110 is shown.

[0173] S311 , thinning the substrate 10 from a side of the substrate 10 away from the first insulating layer 30 .

[0174] Refer to step S111 shown in Figure 10c.

[0175] S312 , etching a first cavity 11 on a side of the thinned substrate 10 facing away from the first insulating layer 30 .

[0176] Reference Fig.10c Step S112 shown.

[0177] S313 , providing a carrier sheet 80 and fixing the carrier sheet 80 on a side of the substrate 10 facing away from the first insulating layer 30 , and the carrier sheet 80 covers the first cavity 11 .

[0178] Reference Fig.10c Step S113 shown.

[0179] In other embodiments of the present application, a method for manufacturing a MEMS resonant device 1 is also provided, which is applied to Figure 7 In the embodiment shown. Fig.15 As shown, in this embodiment, the manufacturing method may include:

[0180] S401, provide SOI.

[0181] Reference Fig.10a Step S101 shown.

[0182] S402 , etching the resonator layer 500 to form the resonator 50 .

[0183] Reference Fig.10a Step S102 is shown.

[0184] S403 , forming a second sacrificial layer 710 on the resonator 50 .

[0185] Reference Fig.14a Step S303 shown.

[0186] S404 , forming a first polysilicon layer 72 on the second sacrificial layer 710 .

[0187] Reference Fig.14a Step S304 is shown.

[0188] S405 , forming a first release hole 725 on the first polysilicon layer 72 .

[0189] Reference Fig.14a Step S305 shown.

[0190] S406 , etching the first sacrificial layer 300 and the second sacrificial layer 710 respectively to form a first insulating layer 30 and a second insulating layer 71 .

[0191] Reference Fig.14b In step S306 , a fourth cavity 723 is formed on the second insulating layer 71 .

[0192] S407, such as Fig.16a As shown, a second polysilicon layer 781 and a third sacrificial layer 79 are formed on the first polysilicon layer 72 .

[0193] The second polysilicon layer 781 includes a plurality of sub-polysilicon layers, and the third sacrificial layer 79 includes two sub-sacrificial layers. The two sub-sacrificial layers separate the three sub-polysilicon layers.

[0194] S408, such as Fig.16a As shown, a third polysilicon layer 782 is formed on the second polysilicon layer 781 and a second release hole 783 is formed.

[0195] The second release hole 783 is disposed above the third sacrificial layer 79 .

[0196] S409, such as Fig.16a As shown, the third sacrificial layer 79 is etched to form a second cavity 77 .

[0197] S410, such as Fig.16b As shown, a polysilicon cap 73 is manufactured on the second polysilicon layer 781 .

[0198] S411 , making an electrical connection portion 76 on the polysilicon upper cover 73 .

[0199] like Fig.16b As shown, the electrical connection portion 76 penetrates from the polysilicon upper cover 73 to the first polysilicon layer 72 .

[0200] S412 , forming a passivation layer 74 on the polysilicon upper cover 73 .

[0201] Reference Fig.10b Step S109 shown.

[0202] S413 , manufacturing a metal electrode 75 on the passivation layer 74 .

[0203] Reference Fig.10c Step S110 is shown.

[0204] S414 , thinning the substrate 10 from a side of the substrate 10 away from the first insulating layer 30 .

[0205] Reference Fig.10c Step S111 is shown.

[0206] S415 , etching a first cavity 11 on a side of the thinned substrate 10 facing away from the first insulating layer 30 .

[0207] Reference Fig.10c Step S112 shown.

[0208] S416 , providing a carrier sheet 80 and fixing the carrier sheet 80 on a side of the substrate 10 facing away from the first insulating layer 30 , and the carrier sheet 80 covers the first cavity 11 .

[0209] Reference Fig.10c Step S113 shown.

[0210] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A micro-electromechanical system (MEMS) resonant device, characterized in that: include: A substrate, a first insulating layer, a resonator and a covering structure are stacked; The resonator includes a vibrator and an anchor point which are arranged in the same layer and connected; The covering structure comprises an electrical connection portion, and a projection of the electrical connection portion on the resonator is located within the range of the anchor point; A first cavity is provided on the substrate, and / or a second cavity is provided on the covering structure; a projection of the first cavity on the resonator overlaps with the anchor point; a projection of the second cavity on the resonator is closer to the vibrator than a projection of the electrical connection portion on the resonator, a projection of the second cavity on the resonator overlaps with the anchor point, and a projection of the second cavity on the resonator does not overlap with the vibrator.

2. The MEMS resonant device according to claim 1, characterized in that: A third cavity is provided on the anchor point, and the projections of the third cavity and the second cavity on the anchor point do not overlap; the third cavity is farther away from the vibrator than the projection of the second cavity on the resonator.

3. The MEMS resonant device according to claim 2, characterized in that: A dimension of the first cavity along a thickness direction of the substrate is smaller than a thickness of the substrate.

4. The MEMS resonant device according to claim 3, characterized in that: The first cavity is disposed on a side of the substrate away from the first insulating layer.

5. The MEMS resonant device according to any one of claims 2 to 4, characterized in that: The first insulating layer includes a first sub-insulating layer and a second sub-insulating layer, a gap is provided between the first sub-insulating layer and the second sub-insulating layer, the gap is connected to the third cavity, and the second sub-insulating layer is closer to the vibrator than the first sub-insulating layer; A projection of a cavity surface of the first cavity close to the first insulating layer on the first insulating layer covers the second sub-insulating layer.

6. The MEMS resonant device according to any one of claims 2 to 5, characterized in that: A dimension of an end of the first cavity away from the first insulating layer along a first direction is greater than a dimension of an end of the first cavity close to the first insulating layer along the first direction, and the first direction is an arrangement direction of the anchor point and the vibrator.

7. The MEMS resonant device according to claim 3, characterized in that: The first cavity is disposed on a side of the substrate facing the first insulating layer.

8. The MEMS resonant device according to any one of claims 2 to 7, characterized in that: The first insulating layer includes a first sub-insulating layer and a second sub-insulating layer, a gap is provided between the first sub-insulating layer and the second sub-insulating layer, the gap is connected to the third cavity, and the second sub-insulating layer is closer to the vibrator than the first sub-insulating layer; A projection of the first cavity on the first insulating layer is located within the range of the second sub-insulating layer.

9. The MEMS resonant device according to any one of claims 1 to 8, characterized in that: The covering structure further includes a second insulating layer located between the resonator and the electrical connection portion, a hollow area is formed on the second insulating layer, and the second cavity is located in the hollow area.

10. The MEMS resonant device according to claim 9, characterized in that: The covering structure further forms a fourth cavity in the hollow area, the projection of the fourth cavity on the resonator covers part of the anchor point and the vibrator, and the fourth cavity is arranged in the same layer as the second cavity and is connected.

11. The MEMS resonant device according to claim 9, characterized in that: The covering structure further forms a fourth cavity in the hollow area, the projection of the fourth cavity on the resonator covers part of the anchor point and the vibrator, and the fourth cavity is in the same layer as the second cavity and is spaced apart.

12. The MEMS resonant device according to any one of claims 1 to 8, characterized in that: The second cavity is located inside the covering structure, and there is a distance between a cavity surface of the second cavity close to the resonator and a surface of the covering structure facing the resonator.

13. The MEMS resonant device according to any one of claims 1 to 12, characterized in that: The MEMS resonant device further includes a carrier, which is disposed on a side of the substrate away from the first insulating layer, and covers the first cavity.

14. A method for manufacturing a MEMS resonant device, characterized in that: The production method comprises: Providing a silicon-on-insulator (SOI) wafer, wherein the SOI comprises a stacked substrate, a sacrificial layer and a resonator layer; Etching the resonator layer to form a resonator, wherein the resonator includes a vibrator and an anchor point that are arranged in the same layer and connected to each other; Making a covering structure on the resonator, and etching the sacrificial layer to form a first insulating layer, wherein the covering structure comprises an electrical connection portion, and a projection of the electrical connection portion on the resonator is located within the range of the anchor point; A first cavity is provided on the substrate, and / or a second cavity is provided on the covering structure; a projection of the first cavity on the resonator overlaps with the anchor point; a projection of the second cavity on the resonator is closer to the vibrator than a projection of the electrical connection portion on the resonator, a projection of the second cavity on the resonator overlaps with the anchor point, and a projection of the second cavity on the resonator does not overlap with the vibrator.

15. The manufacturing method according to claim 14, characterized in that: After the step of manufacturing a covering structure on the resonator, the manufacturing method further comprises: thinning the substrate from a side of the substrate facing away from the first insulating layer; The first cavity is etched on a side of the thinned substrate facing away from the first insulating layer.

16. The manufacturing method according to claim 15, characterized in that: After the step of etching the first cavity on the substrate, the manufacturing method further includes: Provide slides; The carrier is fixed on a side of the substrate facing away from the first insulating layer, and the carrier covers the first cavity.

17. A MEMS device, characterized in that: The invention comprises a circuit and the MEMS resonant device according to any one of claims 1 to 13, wherein the MEMS resonant device is electrically connected to the circuit.

18. An electronic device, characterized in that: The invention comprises a circuit board and the MEMS device according to claim 17, wherein the MEMS device is electrically connected to the circuit board.

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