MEMS sensor based on cymbal structure

Abstract

The invention discloses an MEMS sensor based on a cymbal structure. The cymbal structure in the MEMS sensor comprises an end cover group, an electrode layer group and a piezoelectric layer. The end cover group comprises two end covers, and the two end covers are respectively positioned on the outermost side of the cymbal structure along the direction vertical to the substrate. The electrode layer group comprises two electrode layers, the two electrode layers are in contact with the two end covers respectively, and the piezoelectric layer is located between the two electrode layers. At least one first through hole is formed in the piezoelectric layer. One end cover of the end cover group comprises two extraction electrodes which are independently arranged, one of the two extraction electrodes is electrically connected with the corresponding electrode layer through the first through hole, and the other extraction electrode is directly contacted with the corresponding electrode layer. According to the cymbal structure, one end cover serves as an electrode signal leading-out part, and the two independently arranged leading-out electrodes respectively lead out electrode signals of the corresponding electrode layers through the first through holes, so that an anchor point does not need to be arranged on the end cover to lead out the signals, and the displacement sensitivity of the cymbal structure is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of MEMS sensors, and in particular, to a MEMS sensor based on a cymbal structure. Background Art

[0002] At present, MEMS (Micro-Electro-Mechanical System) technology has achieved rapid development. MEMS devices have the characteristics of small size and thin thickness in structure, and products can be mass-produced. Fully automated assembly has a cost advantage, and many sensors and actuators with large macroscopic sizes have turned to MEMS structures. Existing MEMS sensor structures are diverse and can be generally classified into cantilever beam and circular membrane structures. However, due to the fact that the circular membrane structure is fixed around, the area for receiving sound pressure is small, and the change in central displacement generated is also small; when cantilever beams are arranged in an array, a slit will be generated between two adjacent cantilever beams, and this slit will cause a large degree of attenuation in the response of the output voltage of the MEMS sensor at low frequencies, that is, the so-called air leakage, resulting in a low output voltage and poor performance of the MEMS sensor.

[0003] In addition, there is also a cymbal structure, which can significantly improve the output and receiving sensitivity of MEMS transducers. However, for MEMS sensors based on the cymbal structure, the negative impact of the anchor point in actual preparation is not considered. Exemplarily, the main vibration mode of the ideal cymbal structure is Z-direction vibration, and the signal is amplified through upper and lower end caps. Considering that it is necessary to lead out the signals of the upper and lower electrodes of the sensor, an anchor point needs to be set for electrode routing, but the existence of this anchor point will "alienate" the vibration form of the cymbal structure and significantly reduce the displacement sensitivity. Summary of the Invention

[0004] The present invention provides a MEMS sensor based on a cymbal structure. By using one of the end caps as the electrode signal lead-out part and realizing the independent setting of two lead-out electrodes through the first through holes to respectively lead out the electrode signals of the corresponding electrode layers, there is no need to set an anchor point on the end cap to lead out the signal, thereby improving the displacement sensitivity of the cymbal structure.

[0005] In a first aspect, an embodiment of the present invention provides a MEMS sensor based on a cymbal structure, including a substrate and a cymbal structure located on one side of the substrate;

[0006] The cymbal structure includes an end cap group, an electrode layer group, and a piezoelectric layer;

[0007] The end cap group includes two end caps, and along the direction perpendicular to the substrate, the two end caps are respectively located on the outermost sides of the cymbal structure;

[0008] The electrode layer group includes two electrode layers, the two electrode layers are in contact with the two end covers respectively, and the piezoelectric layer is located between the two electrode layers; at least one first through hole is provided in the piezoelectric layer;

[0009] One of the end caps of the end cap group includes two independently arranged lead-out electrodes, and one of the two lead-out electrodes is electrically connected to the corresponding electrode layer through the first through hole.

[0010] Optionally, the two end covers include an upper end cover and a lower end cover, and the two electrode layers include an upper electrode layer and a lower electrode layer;

[0011] The upper electrode layer is in contact with the upper end cover, and the upper end cover is located on a side of the upper electrode layer away from the piezoelectric layer;

[0012] The lower electrode layer is in contact with the lower end cover, and the lower end cover is located on a side of the lower electrode layer away from the piezoelectric layer;

[0013] Along the thickness direction of the substrate, the lower electrode layer and the first through hole are staggered, and a portion of the upper electrode layer is filled in the first through hole;

[0014] The lower end cover includes an upper lead-out electrode and a lower lead-out electrode which are independently arranged, a portion of the lower lead-out electrode is in direct contact with the lower electrode layer, and a portion of the upper lead-out electrode is electrically connected to the upper electrode layer through the first through hole.

[0015] Optionally, the MEMS sensor further includes a wiring layer;

[0016] The wiring layer is arranged on the substrate, and along the thickness direction of the substrate, the wiring layer is located on a side of the cymbal structure close to the substrate;

[0017] The wiring layer includes a patterned upper wiring electrode and a lower wiring electrode, wherein the upper wiring electrode is insulated from the lower wiring electrode;

[0018] The upper wiring electrode is in direct contact with the upper extraction electrode, and the lower wiring electrode is in direct contact with the lower extraction electrode.

[0019] Optionally, two first through holes are provided in the piezoelectric layer;

[0020] Along the direction of the plane where the substrate is located, the two first through holes are respectively located on two sides of the piezoelectric layer;

[0021] The upper extraction electrode includes two independently arranged upper extraction electrode divisions;

[0022] The two upper lead-out electrode sections are electrically connected to the upper electrode layer through the two first through holes respectively.

[0023] Optionally, the two end covers include an upper end cover and a lower end cover, and the two electrode layers include an upper electrode layer and a lower electrode layer;

[0024] The upper electrode layer is in contact with the upper end cover, and the upper end cover is located on a side of the upper electrode layer away from the piezoelectric layer;

[0025] The lower electrode layer is in contact with the lower end cover, and the lower end cover is located on a side of the lower electrode layer away from the piezoelectric layer;

[0026] Along the thickness direction of the substrate, the upper electrode layer and the first through hole are staggered, and a portion of the lower electrode layer is filled in the first through hole;

[0027] The upper end cover includes an upper lead-out electrode and a lower lead-out electrode which are independently arranged, a portion of the upper lead-out electrode is in direct contact with the upper electrode layer, and a portion of the lower lead-out electrode is electrically connected to the lower electrode layer through the first through hole.

[0028] Optionally, the MEMS sensor further includes a packaging layer, wherein the packaging layer is located on a side of the cymbal structure away from the substrate;

[0029] The encapsulation layer is provided with a second through hole and a third through hole, and along the thickness direction of the substrate, the second through hole at least partially overlaps with the upper lead-out electrode, and the third through hole at least partially overlaps with the lower lead-out electrode;

[0030] A top upper electrode is disposed in the second through hole, and a bottom lower electrode is disposed in the third through hole;

[0031] The top upper electrode is in direct contact with the upper extraction electrode, and the bottom lower electrode is in direct contact with the lower extraction electrode.

[0032] Optionally, two first through holes are provided in the piezoelectric layer;

[0033] Along the direction of the plane where the substrate is located, the two first through holes are respectively located on two sides of the piezoelectric layer;

[0034] The lower extraction electrode includes two independently arranged lower extraction electrode divisions;

[0035] The two lower lead-out electrode sections are electrically connected to the lower electrode layer through the two first through holes respectively.

[0036] Optionally, the MEMS sensor includes a plurality of the cymbal structures located on one side of the substrate;

[0037] A fourth through hole is also provided on the packaging layer, and the fourth through hole is located between two adjacent cymbal structures.

[0038] Optionally, the two end caps include an upper end cap and a lower end cap, and the two electrode layers include an upper electrode layer and a lower electrode layer;

[0039] The upper electrode layer is in contact with the upper end cap, and the upper end cap is located on the side of the upper electrode layer away from the piezoelectric layer;

[0040] The lower electrode layer is in contact with the lower end cap, and the lower end cap is located on the side of the lower electrode layer away from the piezoelectric layer;

[0041] A first gap is formed between the lower end cap and the substrate. The lower end cap protrudes in a direction away from the lower electrode layer to form a first protrusion, and a second gap is formed between the first protrusion and the lower electrode layer; the upper end cap protrudes in a direction away from the upper electrode layer to form a second protrusion, and a third gap is formed between the second protrusion and the upper electrode layer.

[0042] Optionally, the piezoelectric layer is further provided with a fifth through hole;

[0043] Along the thickness direction of the substrate, the fifth through hole at least partially overlaps with the second gap and at least partially overlaps with the third gap.

[0044] In the embodiment of the present invention, the MEMS sensor includes a substrate and a cymbal structure located on one side of the substrate. The cymbal structure includes an end cap group, an electrode layer group, and a piezoelectric layer. Among them, the cymbal structure includes an end cap group, an electrode layer group, and a piezoelectric layer. The end cap group includes two end caps. Along the direction perpendicular to the substrate, the two end caps are respectively located on the outermost sides of the cymbal structure. The electrode layer group includes two electrode layers, and the two electrode layers are respectively in contact with the two end caps. The piezoelectric layer is located between the two electrode layers. At least one first through hole is provided in the piezoelectric layer. One of the end caps in the end cap group includes two independently provided lead-out electrodes. One of the two lead-out electrodes is electrically connected to the corresponding electrode layer through the first through hole, and the other lead-out electrode is directly in contact with the corresponding electrode layer. In this way, by using one of the end caps as the electrode signal lead-out part and using the first through hole to realize the separate lead-out of the electrode signals of the two independently provided lead-out electrodes from the corresponding electrode layers, there is no need to set an anchor point on the end cap to lead out the signal, avoiding the alienation of the vibration form of the cymbal structure caused by the setting of the anchor point, thereby improving the displacement sensitivity of the cymbal structure and enhancing the performance of the MEMS sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a schematic structural diagram of a cymbal structure in the prior art provided by the embodiment of the present invention;

[0046] Figure 2 is a vibration comparison diagram of a cymbal structure in the prior art and an ideal cymbal structure;

[0047] Figure 3 It is a structural schematic diagram of a MEMS sensor based on a cymbal structure provided by an embodiment of the present invention;

[0048] Figure 4 It is Figure 3 a structural schematic diagram of the lower end cap in

[0049] Figure 5 It is Figure 3 a structural schematic diagram of the lower electrode layer in

[0050] Figure 6 It is Figure 3 a structural schematic diagram of one kind of wiring layer in

[0051] Figure 7 It is a structural schematic diagram of another MEMS sensor based on a cymbal structure provided by an embodiment of the present invention;

[0052] Figure 8 It is Figure 7 a structural schematic diagram of one kind of lower end cap in

[0053] Figure 9 It is Figure 7 a structural schematic diagram of one kind of lower electrode layer in

[0054] Figure 10 It is a structural schematic diagram of yet another MEMS sensor based on a cymbal structure provided by an embodiment of the present invention;

[0055] Figure 11 Figure 10 a structural schematic diagram of one kind of upper end cap in

[0056] Figure 12 It is Figure 10 a structural schematic diagram of one kind of upper electrode layer in

[0057] Figure 13 It is a structural schematic diagram of yet another MEMS sensor based on a cymbal structure provided by an embodiment of the present invention;

[0058] Figure 14 It is Figure 13 a structural schematic diagram of one kind of upper end cap in

[0059] Figure 15 It is Figure 13 a structural schematic diagram of one kind of upper electrode layer. Specific embodiments

[0060] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only parts related to the present invention rather than all structures are shown in the drawings.

[0061] Figure 1 It is a schematic structural diagram of a cymbal structure in the prior art provided by an embodiment of the present invention. Figure 2 It is a vibration comparison diagram of the cymbal structure in the prior art and the cymbal structure in the ideal state. Refer to Figure 1 and Figure 2 , the cymbal structure in the prior art includes a substrate 01' and a cymbal structure located on the substrate 01'. The cymbal structure includes an upper end cap 210' and a lower end cap 220'. In addition, the cymbal structure further includes an upper electrode layer and a lower electrode layer located between the upper end cap 210' and the lower end cap 220'. The upper electrode layer is in contact with the upper end cap 210', and the lower electrode layer is in contact with the lower end cap 220'. Considering that it is necessary to lead out the signals of the upper electrode layer and the lower electrode layer, an anchor point 03' needs to be set for electrode routing. As shown in Figure 1 , the anchor point 03' penetrates through the piezoelectric layer and is in contact with the lower electrode layer, so as to lead out the lower electrode signal at the top. However, the setting of the anchor point 03' is equivalent to being fixed on the lower end cap 220', and thus the existence of the anchor point 03' will cause the vibration form of the cymbal structure to be "alienated". Exemplarily, the main vibration mode of the cymbal structure is Z-direction vibration, that is, the cymbal structure can convert the lateral displacement of the piezoelectric layer into the longitudinal displacement of the upper end cap 210' and the lower end cap 220', achieving an amplification effect of the displacement change amount. As shown in the left half of the figure in Figure 2 , when vibrating in the ideal state, the periphery of the lower end cap 220' should warp upward. However, due to the setting of the anchor point 03' (as shown in the right half of Figure 2 ), it will cause part of the lower end cap 220' not to warp upward, making the vibration form of the cymbal structure "alienated", and further significantly reducing the displacement sensitivity of the cymbal structure, affecting the performance of the MEMS sensor.

[0062] Therefore, the present invention provides at least one first through hole in the piezoelectric layer. One of the end caps of the end cap group includes two independently arranged lead-out electrodes, one of the two lead-out electrodes is electrically connected to the corresponding electrode layer through the first through hole, and the other lead-out electrode is directly in contact with the corresponding electrode layer. In this way, by using one of the end caps as the electrode signal lead-out part and realizing that the two independently arranged lead-out electrodes respectively lead out the electrode signals of the corresponding electrode layers through the first through hole, there is no need to set an anchor point on the end cap to lead out the signal, avoiding the alienation of the vibration form of the cymbal structure caused by the setting of the anchor point, thereby improving the displacement sensitivity of the cymbal structure and enhancing the performance of the MEMS sensor.

[0063] The above is the core inventive point of this application. The following will specifically describe the core inventive point of this application in combination with specific embodiments. Figure 3 It is a schematic structure of a MEMS sensor based on a cymbal structure provided by an embodiment of the present invention. Figure 4 isFigure 3 Schematic structural diagram of the lower end cap. Refer to Figure 3 and Figure 4 , the MEMS sensor includes a substrate 01 and a cymbal structure 02 located on one side of the substrate 01. The cymbal structure 02 includes an end cap group 10, an electrode layer group 20, and a piezoelectric layer 30. The end cap group 10 includes two end caps 110. Along the direction perpendicular to the substrate 01, the two end caps 110 are respectively located on the outermost sides of the cymbal structure 02. The electrode layer group 20 includes two electrode layers 210, and the two electrode layers 210 are respectively in contact with the two end caps 110. The piezoelectric layer 30 is located between the two electrode layers 210. At least one first through hole S1 is provided in the piezoelectric layer 30. One of the end caps 110 of the end cap group 10 includes two independently provided lead electrodes 40, and one of the two lead electrodes 40 is electrically connected to the corresponding electrode layer 210 through the first through hole S1.

[0064] Specifically, refer to Figure 3 and Figure 4 , the cymbal structure 02 includes two end caps 110. One of the end caps 110 is located at the uppermost side of the cymbal structure 02, and the other end cap 110 is located at the lowermost side of the cymbal structure 02. The piezoelectric layer 30 is located between the two electrode layers 210. The two electrode layers 210 are located between the two end caps 110, and the two electrode layers 210 are respectively in contact with the two end caps 110. As in Figure 3 and Figure 4 In the described embodiment, the end cap 110 located at the lowermost side of the cymbal structure 02, that is, the lower end cap, can be improved. As in Figure 4As shown, by setting the lower end cap to include two independently provided lead electrodes 40, a gap is provided between the two lead electrodes 40, and the lead electrode with a larger size surrounds the lead electrode with a smaller size. In addition, at least one first through hole S1 is provided in the piezoelectric layer 30. Along the thickness direction of the substrate 01, the first through hole S1 at least partially overlaps with one of the two lead electrodes 40 (the lead electrode 40 with a smaller size). The first through hole S1 can fill the electrode layer 210 located above the piezoelectric layer 30, and then electrically connect one of the lead electrodes 40 to the corresponding electrode layer 210 through the first through hole S1. Herein, the corresponding electrode layer 210 can be understood as the electrode layer 210 that does not contact the end cap 110 provided with the lead electrode 40, while the electrode layer 210 that contacts the end cap 110 provided with the lead electrode 40 directly contacts the other lead electrode 40. Thus, by improving the end cap 110, the electrode signal can be led out through the end cap 110, and the two lead electrodes 40 in the end cap 110 are independently provided. That is, when leading out the electrode signal through the lead electrode 40 with a smaller size, it will not affect the displacement of the entire end cap 110 during vibration. Therefore, compared with the prior art solution that requires setting an anchor point to lead out the electrode signal, the displacement sensitivity of the cymbal structure can be improved, thereby enhancing the performance of the MEMS sensor.

[0065] It should be noted that Figure 3 and Figure 4 only the improvement of the lower end cap is taken as an example for illustration, but it is not limited thereto. In other embodiments, the upper end cap can also be improved, which can be set by those skilled in the art according to needs.

[0066] It should also be noted that the embodiments of the present invention do not limit the shapes and sizes of the two lead electrodes 40, as long as when one of the lead electrodes 40 is electrically connected to the corresponding electrode layer through the first through hole, the size and shape of the other lead electrode 40 will not affect the vibration of the end cap 10.

[0067] It should also be noted that different end caps and different electrode layers in the above figures are distinguished by different color fillings. In the actual manufacturing process, different end caps and different electrode layers can all be made of the same material, which will not be elaborated one by one below.

[0068] In summary, in the embodiment of the present invention, the MEMS sensor includes a substrate and a cymbal structure located on one side of the substrate. The cymbal structure includes an end cap group, an electrode layer group, and a piezoelectric layer. Among them, the cymbal structure includes an end cap group, an electrode layer group, and a piezoelectric layer. The end cap group includes two end caps. Along the direction perpendicular to the substrate, the two end caps are respectively located on the outermost sides of the cymbal structure. The electrode layer group includes two electrode layers, and the two electrode layers are respectively in contact with the two end caps. The piezoelectric layer is located between the two electrode layers. At least one first through hole is provided in the piezoelectric layer. One of the end caps in the end cap group includes two independently provided lead-out electrodes. One of the two lead-out electrodes is electrically connected to the corresponding electrode layer through the first through hole, and the other lead-out electrode is directly in contact with the corresponding electrode layer. In this way, by using one of the end caps as the electrode signal lead-out part and using the first through hole to separately lead out the electrode signals of the two independently provided lead-out electrodes corresponding to the electrode layers, there is no need to set an anchor point on the end cap to lead out the signal, avoiding the vibration form of the cymbal structure being alienated due to the setting of the anchor point, thereby improving the displacement sensitivity of the cymbal structure and enhancing the performance of the MEMS sensor.

[0069] Optionally, on the basis of the above embodiment, Figure 5 Yes Figure 3 is a schematic structural diagram of the lower electrode layer. Referring to Figures 3 - 5 , the two end caps 110 include an upper end cap 111 and a lower end cap 112, and the two electrode layers 210 include an upper electrode layer 211 and a lower electrode layer 212. The upper electrode layer 211 is in contact with the upper end cap 111, and the upper end cap 111 is located on the side of the upper electrode layer 211 away from the piezoelectric layer 30. The lower electrode layer 212 is in contact with the lower end cap 112, and the lower end cap 112 is located on the side of the lower electrode layer 212 away from the piezoelectric layer 30. Along the thickness direction of the substrate 01, the lower electrode layer 212 is staggeredly arranged with the first through hole S1, and the first through hole S1 is filled with a part of the upper electrode layer 211. The lower end cap 112 includes an upper lead-out electrode 410 and a lower lead-out electrode 420 which are independently provided. A part of the lower lead-out electrode 420 is directly in contact with the lower electrode layer 212, and a part of the upper lead-out electrode 410 is electrically connected to the upper electrode layer 211 through the first through hole S1.

[0070] Specifically, in the embodiment of the present invention, the lower end cap 112 is provided with an upper lead electrode 410 and a lower lead electrode 420 which are independently arranged. A gap is provided between the upper lead electrode 410 and the lower lead electrode 420, and the size of the lower lead electrode 420 is much larger than that of the upper lead electrode 410. In addition, a first through hole S1 is also provided in the piezoelectric layer 30. Along the thickness direction of the substrate 01, the first through hole S1 at least partially overlaps with the upper lead electrode 410, and a part of the upper electrode layer 211 is filled in the first through hole S1. At this time, the lower electrode layer 212 is also provided between the upper electrode layer 211 and the upper lead electrode 410. Therefore, if the electrical connection between the upper electrode layer 211 and the upper lead electrode 410 is to be realized, the lower electrode layer 212 needs to be adaptively set. As Figure 5 shown, etch the position corresponding to the first through hole S1 in the entire layer of the lower electrode layer 212, so that a part of the upper electrode layer 211 in the first through hole S1 can contact the upper lead electrode 410 through the lower electrode layer 212, ensuring that the upper electrode signal is led out at the position of the lower end cap 112. It can be understood that, in order to avoid signal crosstalk between the upper electrode layer 211 and the lower electrode layer 212, a larger part needs to be etched at the position corresponding to the first through hole S1 in the lower electrode layer 212 to ensure the insulation between the upper electrode layer 211 and the lower electrode layer 212. In this way, the upper lead electrode 410 is electrically connected to the upper electrode layer 211 through the first through hole S1, so that the upper electrode signal is led out at the position of the lower end cap 112. Since the lower lead electrode 420 is directly in contact with the lower electrode layer 212, the lower electrode signal can be led out at the position of the lower end cap 112. And the two lead electrodes 40 in the lower end cap 112 are independently arranged. Therefore, when the upper lead electrode 410 with a smaller size is electrically connected to the upper electrode layer 211 through the first through hole S1, it will not affect the displacement of the lower end cap 112 during vibration. Therefore, compared with the prior art solution that needs to set anchor points to lead out electrode signals, the displacement sensitivity of the cymbal structure can be improved, thereby improving the performance of the MEMS sensor.

[0071] Optionally, on the basis of the above embodiment, Figure 6 is Figure 3 a schematic structural diagram of a wiring layer in. Refer to Figures 3 - 6 , the MEMS sensor further includes a wiring layer 50. The wiring layer 50 is arranged on the substrate 01. Along the thickness direction of the substrate 01, the wiring layer 50 is located on the side of the cymbal structure 02 close to the substrate 01. The wiring layer 50 includes a patterned upper wiring electrode 510 and a lower wiring electrode 520, and the upper wiring electrode 510 and the lower wiring electrode 520 are insulated from each other. The upper wiring electrode 510 is in direct contact with the upper lead electrode 410, and the lower wiring electrode 510 is in direct contact with the lower lead electrode 420.

[0072] Specifically, as Figures 3 - 6In the embodiment shown, when the upper electrode signal and the lower electrode signal are led out through the lower end cap 112, a wiring layer 50 also needs to be provided between the cymbal structure 02 and the substrate 01. The wiring layer 50 includes a patterned upper wiring electrode 510 and a lower wiring electrode 520. Along the thickness direction of the substrate 01, the upper wiring electrode 510 at least partially overlaps and contacts the upper lead-out electrode 410, and the lower wiring electrode 520 at least partially overlaps and contacts the lower lead-out electrode 420, so that the upper electrode lead-out signal and the lower electrode lead-out signal can be introduced into the substrate 01 through the wiring layer 50, facilitating the subsequent lead-out of the electrode signal from the substrate 01.

[0073] Optionally, based on the above embodiment, Figure 7 is a schematic structural diagram of another MEMS sensor based on a cymbal structure provided by an embodiment of the present invention. Figure 8 is Figure 7 a schematic structural diagram of a structure of the lower end cap in Figure 9 is Figure 7 a schematic structural diagram of a structure of the lower electrode layer in Figures 7 - 9 Referring to

[0074] Specifically, in the embodiment shown in Figure 7 and Figure 8 , two first through holes S1 are provided in the piezoelectric layer 30. Along the direction of the plane where the substrate 01 is located, the two first through holes S1 are respectively located on both sides of the piezoelectric layer 30. The upper lead-out electrode 410 includes two independently provided upper lead-out electrode parts 411. The two upper lead-out electrode parts 411 are respectively electrically connected to the upper electrode layer 211 through the two first through holes S1. Figure 9 Specifically, in the embodiment shown in

[0075] Optionally, in another embodiment, Figure 10 is a schematic structural diagram of another MEMS sensor based on a cymbal structure provided by an embodiment of the present invention. Figure 11 Figure 10A structural diagram of the middle and upper end cover. Figure 12 yes Figure 10 A schematic diagram of the structure of the middle and upper electrode layers. Figures 10 - 12 , the two end caps 110 include an upper end cap 111 and a lower end cap 112, and the two electrode layers 210 include an upper electrode layer 211 and a lower electrode layer 212. The upper electrode layer 211 contacts the upper end cap 111, and the upper end cap 111 is located on the side of the upper electrode layer 211 away from the piezoelectric layer 30. The lower electrode layer 212 contacts the lower end cap 112, and the lower end cap 112 is located on the side of the lower electrode layer 212 away from the piezoelectric layer 30. Along the thickness direction of the substrate 01, the upper electrode layer 211 and the first through hole S1 are staggered, and part of the lower electrode layer 212 is filled in the first through hole S1. The upper end cap 111 includes an upper extraction electrode 410 and a lower extraction electrode 420 that are independently arranged, a part of the upper extraction electrode 410 is in direct contact with the upper electrode layer 211, and a part of the lower extraction electrode 420 is electrically connected to the lower electrode layer 212 through the first through hole S1.

[0076] Specifically, in the embodiment of the present invention, the lower end cover 112 is provided to include an independently provided upper lead electrode 410 and a lower lead electrode 420. A gap is provided between the upper lead electrode 410 and the lower lead electrode 420, and the size of the lower lead electrode 420 is much smaller than the size of the upper lead electrode 410. In addition, a first through hole S1 is also provided in the piezoelectric layer 30. Along the thickness direction of the substrate 01, the first through hole S1 at least partially overlaps with the lower lead electrode 420, and a portion of the lower electrode layer 212 is filled in the first through hole S1. At this time, the lower electrode layer 212 and the lower lead electrode 420 are separated by the upper electrode layer 211. Therefore, if the electrical connection between the lower electrode layer 212 and the lower lead electrode 420 is to be achieved, the upper electrode layer 211 also needs to be adaptively provided. As Figure 12As shown, the position of the upper electrode layer 211 corresponding to the first through hole S1 in the etched entire layer is etched, so that a part of the lower electrode layer 212 in the first through hole S1 can contact the lower lead electrode 420 through the upper electrode layer 211, ensuring that the lower electrode signal is led out at the position of the upper end cap 111. It can be understood that in order to avoid signal crosstalk between the upper electrode layer 211 and the lower electrode layer 212, a relatively large part needs to be etched at the position of the upper electrode layer 211 corresponding to the first through hole S1 to ensure insulation between the upper electrode layer 211 and the lower electrode layer 212. In this way, the lower lead electrode 420 is electrically connected to the lower electrode layer 212 through the first through hole S1, so that the lower electrode signal is led out at the position of the upper end cap 111. Since the upper lead electrode 410 is directly in contact with the upper electrode layer 211, the upper electrode signal can be led out at the position of the upper end cap 111. And the two lead electrodes 40 in the upper end cap 111 are independently arranged. Therefore, when the lower lead electrode 420 with a smaller size is electrically connected to the lower electrode layer 212 through the first through hole S1, it will not affect the displacement of the upper end cap 111 during vibration. Therefore, compared with the prior art solution that requires an anchor point to lead out the electrode signal, the displacement sensitivity of the cymbal structure can be improved, thereby improving the performance of the MEMS sensor.

[0077] Optionally, on the basis of the above embodiment, continue to refer to Figure 10 , the MEMS sensor further includes a packaging layer 60, and the packaging layer 60 is located on the side of the cymbal structure away from the substrate 01. The packaging layer 60 is provided with a second through hole S2 and a third through hole S3. Along the thickness direction of the substrate 01, the second through hole S2 at least partially overlaps with the upper lead electrode 410, and the third through hole S3 at least partially overlaps with the lower lead electrode 420. A top upper electrode 610 is arranged in the second through hole S2, and a bottom lower electrode 620 is arranged in the third through hole S3. The top upper electrode 610 is directly in contact with the upper lead electrode 410, and the bottom lower electrode 620 is directly in contact with the lower lead electrode 420.

[0078] Specifically, in the embodiment shown in Figures 10 - 12 , when leading out the upper electrode signal and the lower electrode signal through the upper end cap 111, the packaging layer 60 can be arranged on the cymbal structure by bonding. The packaging layer 60 is provided with a second through hole S2 and a third through hole S3. Along the thickness direction of the substrate 01, the second through hole S2 at least partially overlaps with the upper lead electrode 410, and the third through hole S3 at least partially overlaps with the lower lead electrode 420. A top upper electrode 610 is arranged in the second through hole S2, and a bottom lower electrode 620 is arranged in the third through hole S3. The top upper electrode 610 is directly in contact with the upper lead electrode 410, and the bottom lower electrode 620 is directly in contact with the lower lead electrode 420, so that the upper electrode lead-out signal and the lower electrode lead-out signal can be led to the outside through the packaging layer 60, facilitating the subsequent lead-out of the electrode signal by the packaging layer 60.

[0079] In another embodiment, Figure 13 is a schematic structure of another MEMS sensor based on a cymbal structure provided by an embodiment of the present invention, Figure 14 is Figure 13 a schematic structure diagram of an upper end cap in Figure 15 is Figure 13 a schematic structure diagram of an upper electrode layer in. Refer to Figures 13 - 15 , two first through holes S1 are provided in the piezoelectric layer 30. Along the direction of the plane where the substrate 01 is located, the two first through holes S1 are respectively located on both sides of the piezoelectric layer 30. The lower lead-out electrode 420 includes two independently provided lower lead-out electrode branches 421. The two lower lead-out electrode branches 421 are respectively electrically connected to the lower electrode layer 212 through the two first through holes S1.

[0080] Specifically, in the embodiment shown in Figure 13 , the two first through holes S1 are respectively located on the left and right sides of the piezoelectric layer 30, and the two first through holes S1 are both filled with a part of the lower electrode layer 212. In addition, at positions corresponding to the two first through holes S1 in the upper end cap 111, there are also two independently provided lower lead-out electrode branches 421. To ensure that the two lower lead-out electrode branches 421 are respectively electrically connected to the part of the lower electrode layer 212 in the two first through holes S1, further, the upper electrode layer 211 between the piezoelectric layer 30 and the upper end cap 111 needs to be correspondingly hollowed out, that is, as shown in Figure 15 , the partial electrode layers on the left and right sides of the upper electrode layer 211 are etched away, so that the two lower lead-out electrode branches 421 are respectively in direct contact with the part of the lower electrode layer 212 in the two first through holes S1. In this way, by setting the lower lead-out electrode 420 of the upper end cap 111 to include two symmetrically and insulatedly arranged lower lead-out electrode branches 421, the symmetry of the lower electrode lead-out signal can be ensured.

[0081] Optionally, on the basis of the above embodiment, continue to refer to Figure 13 , the MEMS sensor includes a plurality of cymbal structures 02 located on one side of the substrate 01. A fourth through hole S4 is also provided on the encapsulation layer 60, and the fourth through hole S4 is located between two adjacent cymbal structures 02. Specifically, by providing the fourth through hole S4 on the encapsulation layer 60 between two adjacent cymbal structures 02, the liquid or gas between the two cymbal structures 02 during the preparation process can be released through the fourth through hole S4.

[0082] Optionally, on the basis of the above embodiment, continue to refer to Figure 10, the two end caps 110 include an upper end cap 111 and a lower end cap 112, and the two electrode layers 210 include an upper electrode layer 211 and a lower electrode layer 212. The upper electrode layer 211 is in contact with the upper end cap 111, and the upper end cap 111 is located on the side of the upper electrode layer 211 away from the piezoelectric layer 30. The lower electrode layer 212 is in contact with the lower end cap 112, and the lower end cap 112 is located on the side of the lower electrode layer 212 away from the piezoelectric layer 30. A first gap T1 is formed between the lower end cap 112 and the substrate 01. The lower end cap 112 protrudes in a direction away from the lower electrode layer 212 to form a first protrusion (not shown in the figure), and a second gap T2 is formed between the first protrusion and the lower electrode layer 212. The upper end cap 111 protrudes in a direction away from the upper electrode layer 211 to form a second protrusion (not shown in the figure), and a third gap T3 is formed between the second protrusion and the upper electrode layer 211.

[0083] Specifically, the substrate 01 is the basic structure of the MEMS sensor, mainly playing a supporting role so that a cymbal structure can be formed on one side of the substrate 01 subsequently. Exemplarily, the material of the substrate 01 may include silicon. The cymbal structure is often used to prepare a piezoelectric transducer. The cymbal structure includes a lower end cap 112, a lower electrode layer 212, a piezoelectric layer 30, an upper electrode layer 211, and an upper end cap 111 arranged in sequence along the direction perpendicular to one side surface of the substrate 01. A first gap T1 is formed between the lower end cap 112 and the substrate 01. The lower end cap 112 protrudes in a direction away from the lower electrode layer 212 to form a first protrusion, a second gap T2 is formed between the first protrusion and the lower electrode layer 212, and the upper end cap 111 protrudes in a direction away from the upper electrode layer 211 to form a second protrusion, and a third gap T3 is formed between the second protrusion and the upper electrode layer 211. That is, the second gap T2 formed between the lower end cap 112 and the lower electrode layer 212 can be used as a lower release cavity provided for the displacement change when the lower end cap 112 deforms, and the third gap T3 formed between the upper end cap 111 and the upper electrode layer 211 can be used as an upper release cavity provided for the displacement change when the upper end cap 111 deforms. Among them, the lower electrode layer 212 and the upper electrode layer 211 are arranged on opposite sides of the piezoelectric layer 30. When a certain voltage is applied to the lower electrode layer 212 and the upper electrode layer 211, the piezoelectric layer 30 can generate a certain displacement change in the lateral direction, generating a displacement change amount. The lower end cap 112 and the upper end cap 111 are used to generate a telescopic change perpendicular to the telescopic direction of the piezoelectric layer 30 according to the expansion and contraction of the piezoelectric layer 30. That is to say, the cymbal structure can convert the lateral displacement of the piezoelectric layer 30 into the longitudinal displacement of the upper end cap 111 and the lower end cap 112, achieving an amplification effect of the displacement change amount. In addition, in this embodiment, the material of the piezoelectric layer 30 may include one of piezoelectric materials such as aluminum nitride, anti-doped aluminum nitride, zinc oxide, and lead zirconate titanate. The materials of the lower end cap 112, the lower electrode layer 212, the upper electrode layer 211, and the upper end cap 212 may all include metal materials with a relatively large Young's modulus such as molybdenum, copper, or tungsten.

[0084] Optionally, based on the above embodiments, continue to refer to Figure 10 , the piezoelectric layer 30 is further provided with a fifth through hole S5. Along the thickness direction of the substrate 01, the fifth through hole S5 at least partially overlaps with the second void T2 and at least partially overlaps with the third void T3. Specifically, a fifth through hole S5 penetrating the second void T2 and the third void T3 is further provided in the piezoelectric layer 30, so as to release the liquid or gas in the second void T2 and the third void T3 during the preparation process through the fifth through hole S5.

[0085] Note that the above are only the preferred embodiments of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein. Various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A MEMS sensor based on a cymbal structure, characterized in that: It includes a substrate, and a cymbal structure located on one side of the substrate; The cymbal structure includes an end cap group, an electrode layer group and a piezoelectric layer; The end cap group includes two end caps, and along a direction perpendicular to the substrate, the two end caps are respectively located at the outermost sides of the cymbal structure; The electrode layer group includes two electrode layers, the two electrode layers are in contact with the two end covers respectively, and the piezoelectric layer is located between the two electrode layers; at least one first through hole is provided in the piezoelectric layer; One of the end caps of the end cap group includes two independently arranged lead-out electrodes, and one of the two lead-out electrodes is electrically connected to the corresponding electrode layer through the first through hole.

2. The MEMS sensor according to claim 1, characterized in that: The two end covers include an upper end cover and a lower end cover, and the two electrode layers include an upper electrode layer and a lower electrode layer; The upper electrode layer is in contact with the upper end cover, and the upper end cover is located on a side of the upper electrode layer away from the piezoelectric layer; The lower electrode layer is in contact with the lower end cover, and the lower end cover is located on a side of the lower electrode layer away from the piezoelectric layer; Along the thickness direction of the substrate, the lower electrode layer and the first through hole are staggered, and a portion of the upper electrode layer is filled in the first through hole; The lower end cover includes an upper lead-out electrode and a lower lead-out electrode which are independently arranged, a portion of the lower lead-out electrode is in direct contact with the lower electrode layer, and a portion of the upper lead-out electrode is electrically connected to the upper electrode layer through the first through hole.

3. The MEMS sensor according to claim 2, characterized in that: The MEMS sensor also includes a wiring layer; The wiring layer is arranged on the substrate, and along the thickness direction of the substrate, the wiring layer is located on a side of the cymbal structure close to the substrate; The wiring layer includes a patterned upper wiring electrode and a lower wiring electrode, wherein the upper wiring electrode is insulated from the lower wiring electrode; The upper wiring electrode is in direct contact with the upper extraction electrode, and the lower wiring electrode is in direct contact with the lower extraction electrode.

4. The MEMS sensor according to claim 2, characterized in that: The piezoelectric layer is provided with two first through holes; Along the direction of the plane where the substrate is located, the two first through holes are respectively located on two sides of the piezoelectric layer; The upper extraction electrode includes two independently arranged upper extraction electrode divisions; The two upper lead-out electrode sections are electrically connected to the upper electrode layer through the two first through holes respectively.

5. The MEMS sensor according to claim 1, characterized in that: The two end covers include an upper end cover and a lower end cover, and the two electrode layers include an upper electrode layer and a lower electrode layer; The upper electrode layer is in contact with the upper end cover, and the upper end cover is located on a side of the upper electrode layer away from the piezoelectric layer; The lower electrode layer is in contact with the lower end cover, and the lower end cover is located on a side of the lower electrode layer away from the piezoelectric layer; Along the thickness direction of the substrate, the upper electrode layer and the first through hole are staggered, and a portion of the lower electrode layer is filled in the first through hole; The upper end cap includes an upper lead electrode and a lower lead electrode that are independently provided. A part of the upper lead electrode is in direct contact with the upper electrode layer, and a part of the lower lead electrode is electrically connected to the lower electrode layer through the first through hole.

6. The MEMS sensor according to claim 5, wherein the MEMS sensor further includes a packaging layer, and the packaging layer is located on a side of the cymbal structure away from the substrate; a second through hole and a third through hole are provided on the packaging layer. Along the thickness direction of the substrate, the second through hole at least partially overlaps with the upper lead electrode, and the third through hole at least partially overlaps with the lower lead electrode; a top upper electrode is provided in the second through hole, and a bottom lower electrode is provided in the third through hole; the top upper electrode is in direct contact with the upper lead electrode, and the bottom lower electrode is in direct contact with the lower lead electrode.

7. The MEMS sensor according to claim 5, wherein two of the first through holes are provided in the piezoelectric layer; along the direction of the plane where the substrate is located, the two first through holes are respectively located on two sides of the piezoelectric layer; the lower lead electrode includes two independently provided lower lead electrode parts; the two lower lead electrode parts are respectively electrically connected to the lower electrode layer through the two first through holes.

8. The MEMS sensor according to claim 6, wherein the MEMS sensor includes a plurality of the cymbal structures located on one side of the substrate; a fourth through hole is further provided on the packaging layer, and the fourth through hole is located between two adjacent cymbal structures.

9. The MEMS sensor according to claim 1, wherein the two end caps include an upper end cap and a lower end cap, and the two electrode layers include an upper electrode layer and a lower electrode layer; the upper electrode layer is in contact with the upper end cap, and the upper end cap is located on a side of the upper electrode layer away from the piezoelectric layer; the lower electrode layer is in contact with the lower end cap, and the lower end cap is located on a side of the lower electrode layer away from the piezoelectric layer; a first gap is formed between the lower end cap and the substrate, the lower end cap protrudes in a direction away from the lower electrode layer to form a first protrusion, and a second gap is formed between the first protrusion and the lower electrode layer; the upper end cap protrudes in a direction away from the upper electrode layer to form a second protrusion, and a third gap is formed between the second protrusion and the upper electrode layer.

10. The MEMS sensor according to claim 9, wherein a fifth through hole is further provided in the piezoelectric layer; along the thickness direction of the substrate, the fifth through hole at least partially overlaps with the second gap and at least partially overlaps with the third gap.

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