Ultrasonic flight sensor and manufacturing method thereof

Abstract

The present invention provides an ultrasonic flight sensor and a manufacturing method thereof, comprising a semiconductor substrate, a support layer disposed on the surface of the semiconductor substrate and having an inner hole, an elastic film covering the inner hole and disposed on the surface of the support layer, and an excitation layer disposed in the inner hole and attached to the surface of the elastic film facing the inner hole, wherein the excitation layer is patterned and comprises a first electrode layer, a second electrode layer, and a piezoelectric layer disposed between the first electrode layer and the second electrode layer. The present invention adopts semiconductor technology to manufacture the ultrasonic flight sensor, realizes miniaturization and easy integration of the ultrasonic flight sensor, and helps the electronic equipment using the ultrasonic sensor to realize miniaturization and thinness.

Description

Technical Field

[0001] The present invention relates to the field of ultrasonic sensors, and in particular to an ultrasonic flight sensor and a manufacturing method thereof. Background Art

[0002] Ultrasonic sensors are widely used in consumer electronics, robots, drones, medical instruments and other fields. For example, they can measure distance, position tracking, personnel detection, robot obstacle avoidance, medical imaging, etc. As a device that converts electrical energy and mechanical energy, the ultrasonic transducer is an important component of the ultrasonic sensor. Traditional ultrasonic transducers are usually made based on mechanical processing, so they have the disadvantages of large size, low processing accuracy, high processing cost, and difficulty in forming an array structure.

[0003] Piezoelectric microultrasonic transducer (PMUT) is composed of an elastic membrane, a piezoelectric layer, and upper and lower metal electrodes. It uses the bending vibration mode of the elastic membrane to transmit and receive ultrasonic waves. It has the advantages of low driving voltage, low output impedance, and good transmission and reception efficiency. Therefore, it has been used in many occasions, such as ultrasonic flight sensors.

[0004] Ultrasonic flight sensors can be used for distance measurement, position tracking, presence detection, and obstacle avoidance in consumer electronics, robotics, drones, and other fields. Compared with optical sensors or infrared sensors, it has many advantages. It can provide the most accurate distance measurement, is not affected by the size or color of the target object, is not disturbed by environmental noise, and can be used in direct sunlight. These advantages, as well as the ruggedness, accuracy, and reliability of ultrasonic sensors have made them widely used in industrial and automotive applications. However, existing ultrasonic flight sensors are basically made and assembled using discrete devices, are large in size, and are not easy to integrate, making them difficult to apply to miniaturized or lightweight electronic products. Summary of the invention

[0005] The object of the present invention is to provide an ultrasonic flight sensor and a manufacturing method thereof, so as to realize miniaturization and easy integration of the ultrasonic flight sensor.

[0006] To achieve the above object, the present invention provides an ultrasonic flight sensor, which is manufactured using semiconductor technology and includes:

[0007] Semiconductor substrate;

[0008] A support layer is disposed on the surface of the semiconductor substrate and has an inner hole;

[0009] An elastic membrane, covering the inner hole and disposed on the surface of the supporting layer;

[0010] The excitation layer is disposed in the inner hole and attached to the surface of the elastic film facing the inner hole; wherein,

[0011] The excitation layer is patterned and includes: a first electrode layer, a second electrode layer, and a piezoelectric layer disposed between the first electrode layer and the second electrode layer; the elastic film is provided with an opening, and the opening penetrates the excitation layer and communicates with the inner hole.

[0012] Optionally, the patterned shapes of the first electrode layer, the second electrode layer and the piezoelectric layer are the same or similar.

[0013] Optionally, the elastic film is provided with an opening, and the opening passes through the excitation layer and is connected with the inner hole.

[0014] Optionally, the opening is arranged in a central area of ​​the elastic membrane portion corresponding to the inner hole.

[0015] Optionally, the patterned main body of the excitation layer is arranged around the central area of ​​the inner hole or the opening.

[0016] Optionally, at least two supporting ribs are symmetrically arranged around a main body portion of the excitation layer, and the supporting ribs extend from the main body portion toward a peripheral portion of the inner hole.

[0017] Optionally, at least one of the ribs extends to the outer periphery of the inner hole and enters the supporting layer.

[0018] Optionally, it also includes a first electrical contact hole and a second electrical contact hole arranged on the periphery of the inner hole; the first electrical contact hole and the second electrical contact hole are electrically connected to the first electrode layer and the second electrode layer in the rib respectively.

[0019] Optionally, the excitation layer further includes the first electrode layer and the second electrode layer extending into the support layer.

[0020] Optionally, it also includes a first electrical contact hole and a second electrical contact hole arranged near the excitation layer extending to the support layer; the first electrical contact hole and the second electrical contact hole are filled with conductive materials and are electrically connected to the first electrode layer and the second electrode layer in the nearby excitation layer respectively.

[0021] Optionally, an edge position of the inner hole contacting the supporting layer of the elastic membrane is recessed toward the supporting layer by a preset distance to form a hole eave of a regular shape.

[0022] Accordingly, the present invention also provides a method for manufacturing an ultrasonic flight sensor, which comprises:

[0023] providing a substrate;

[0024] forming an elastic film on the surface of the substrate;

[0025] Making an excitation layer on the surface of the elastic film and patterning it;

[0026] Making a support layer on the surface of the substrate having the excitation layer;

[0027] Opening an inner hole in the support layer;

[0028] providing a wafer;

[0029] placing a substrate having a support layer with inner holes formed thereon upside down on the wafer; and

[0030] The substrate is removed.

[0031] Optionally, the step of preparing the incentive layer includes:

[0032] manufacturing a first electrode layer;

[0033] Fabricating a piezoelectric layer on the fabricated first electrode layer;

[0034] A second electrode layer is fabricated on the fabricated piezoelectric layer.

[0035] Optionally, the first electrode layer, the piezoelectric layer and the second electrode layer after patterning have the same or similar shapes.

[0036] Optionally, after removing the substrate, an opening is made in the portion of the elastic membrane covering the inner hole.

[0037] Optionally, the method further includes manufacturing a cave eaves support body on the elastic membrane after patterning the excitation layer and before forming the support layer.

[0038] Optionally, the method further includes removing the cave eaves support body after making an opening in the portion of the elastic membrane covering the inner hole.

[0039] Optionally, the method further includes making a first electrical contact hole and a second electrical contact hole on the elastic film extending to the support layer portion and the excitation layer.

[0040] Optionally, a corresponding driving circuit is arranged on the wafer, and the driving circuit includes a first contact pad and a second contact pad.

[0041] Optionally, the first electrical contact hole and the second electrical contact hole penetrate the support layer; the first electrical contact hole and the second electrical contact hole are filled with conductive material to electrically connect the first electrical contact hole and the second electrical contact hole to the first contact pad and the second contact pad respectively.

[0042] Optionally, the method further includes filling the first electrical contact hole and the second electrical contact hole with a conductive material, so that the first electrical contact hole is electrically connected to the first electrode layer, and the second electrical contact hole is electrically connected to the second electrode layer.

[0043] In summary, the present invention provides an ultrasonic flight sensor and a manufacturing method thereof, comprising a semiconductor substrate, a support layer disposed on the surface of the semiconductor substrate and having an inner hole, an elastic film covering the inner hole and disposed on the surface of the support layer, and an excitation layer disposed in the inner hole and attached to the surface of the elastic film facing the inner hole, wherein the excitation layer comprises a first electrode layer, a second electrode layer, and a piezoelectric layer disposed between the first electrode layer and the second electrode layer. The present invention adopts semiconductor technology to manufacture the ultrasonic flight sensor, realizes miniaturization and easy integration of the ultrasonic flight sensor, and helps to achieve miniaturization and thinness of the volume of electronic equipment using the ultrasonic sensor.

[0044] Furthermore, in the present invention, the excitation layer is patterned and designed, and part of the piezoelectric layer material is removed, thereby reducing the influence of the piezoelectric layer stress on the ultrasonic flight sensor and helping to improve the performance of the miniaturized ultrasonic flight sensor.

[0045] Furthermore, in the process of manufacturing the ultrasonic flight sensor, after patterning the excitation layer, a hole eaves support body is made on the elastic membrane to reduce the subsequent deformation of the bonding point between the support layer and the elastic membrane, thereby weakening or even avoiding the influence of the deformation at the bonding point between the support layer and the elastic membrane on the performance of the ultrasonic flight sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0047] Figure 1 A top view of a partial structure of an ultrasonic flight sensor provided in Embodiment 1 of the present invention;

[0048] Figure 2a for Figure 1 Schematic diagram of the cross-section structure along line AA. Figure 2b for Figure 1 Schematic diagram of the cross-section structure along line BB;

[0049] Figure 3 A top view of a partial structure of an ultrasonic flight sensor provided in Embodiment 2 of the present invention;

[0050] Figure 4a for Figure 3 Schematic diagram of the cross-section structure along the CC line, Figure 4b for Figure 3 Schematic diagram of the cross-section structure along line DD; Figure 4c for Figure 3 Schematic diagram of the cross-section structure along line EE;

[0051] Figure 5 A flowchart of a method for manufacturing an ultrasonic flight sensor provided in Embodiment 2 of the present invention;

[0052] Figures 6a to 6k A schematic diagram of the structure of corresponding steps of the method for manufacturing an ultrasonic flight sensor provided in the second embodiment of the present invention;

[0053] Figures 7a to 7j A schematic diagram of the structure of corresponding steps of a method for manufacturing an ultrasonic flight sensor provided in Embodiment 3 of the present invention;

[0054] Figures 8a to 8l A schematic structural diagram of corresponding steps of a method for manufacturing an ultrasonic flight sensor provided in a fourth embodiment of the present invention;

[0055] Wherein, the accompanying drawings are marked as follows:

[0056] 100-substrate; 200-semiconductor substrate (wafer); 101-elastic membrane; 102-seed layer; 103-first electrode layer; 104-piezoelectric layer; 105-second electrode layer; 106-passivation layer; 107-support layer; 108a-first electrical contact hole; 108b-second electrical contact hole; 108a′-first opening; 108b′-second opening; 109-conductive material; 110-excitation layer; 110a-main body; 110b-rib; 111-eaves support body; 120-inner hole; 130-opening; 140-contact pad; 140a-first contact pad; 140b-second contact pad. DETAILED DESCRIPTION

[0057] The ultrasonic flight sensor and its manufacturing method of the present invention are further described in detail below in conjunction with the accompanying drawings and specific embodiments. According to the following description and drawings, the advantages and features of the present invention will be more clear. However, it should be noted that the concept of the technical solution of the present invention can be implemented in a variety of different forms and is not limited to the specific embodiments described herein. The drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0058] The terms "first", "second", etc. in the specification are used to distinguish between similar elements and are not necessarily used to describe a specific order or time sequence. It is to be understood that, where appropriate, these terms used in this way are interchangeable, for example, so that the embodiments of the present invention described herein can be operated in an order other than that described or shown herein. Similarly, if the method described herein includes a series of steps, the order of these steps presented herein is not necessarily the only order in which these steps can be performed, and some of the steps described may be omitted and / or some other steps not described herein may be added to the method. If the components in a certain figure are the same as the components in other figures, although these components can be easily identified in all figures, in order to make the description of the figures clearer, this specification will not mark all the same component numbers in each figure.

[0059] Embodiment 1

[0060] Figure 1 A top view of a partial structure of the ultrasonic flight sensor provided in this embodiment, Figure 2a for Figure 1 Schematic diagram of the cross-section structure along line AA. Figure 2b for Figure 1 Schematic diagram of the cross-sectional structure along line BB.

[0061] refer to Figure 1 , Figure 2a and Figure 2b As shown, the ultrasonic flight sensor provided in this embodiment includes a semiconductor substrate 200, a support layer 107, an elastic film 101 and an excitation layer 110. The support layer 107 is disposed on the surface of the semiconductor substrate 200, and an inner hole 120 is opened in the central area of ​​the support layer 107; the elastic film 101 covers the inner hole 120 and is disposed on the surface of the support layer 107; the excitation layer 110 is disposed in the inner hole 120 and attached to the surface of the elastic film 101 facing the inner hole 120, and the excitation layer 110 includes: a first electrode layer 103, a second electrode layer 105, and a piezoelectric layer 104 disposed between the first electrode layer 103 and the second electrode layer 105.

[0062] The excitation layer 101 is patterned, and the excitation layer 110b includes a main body 110a and at least two ribs 110b. The patterned main body 110a of the excitation layer 110 is arranged around the central area of ​​the inner hole 120 or the opening 130. The patterned shapes of the first electrode layer 103, the second electrode layer 105 and the piezoelectric layer 104 are the same or similar. For example, the first electrode layer 103, the second electrode layer 105 and the piezoelectric layer 104 are distributed in a ring shape around the central area of ​​the inner hole 120. When the excitation layer 110 receives an excitation signal, the excitation layer 110 and the elastic membrane 101 generate a vibration of a preset frequency and generate an ultrasonic wave. The relationship between the preset frequency and the radius of the inner hole is generally represented by the following formula (1):

[0063]

[0064] Among them, f0 is the frequency of vibration, a is the radius of the inner hole; D is the bending stiffness of the vibration diaphragm composed of the excitation layer and the elastic membrane, and ρ is the density of the vibration diaphragm.

[0065] It can be seen from the above formula (1) that the operating frequency of the vibration diaphragm is inversely related to the radius of the inner hole, that is, the lower the operating frequency of the vibration diaphragm, the larger the radius of the inner hole is required. The ultrasonic signal generated by the ultrasonic flight sensor needs to be propagated into the air. Since the attenuation of sound waves in the air increases with the increase of its frequency, in order to ensure that the ultrasonic wave generated by the ultrasonic flight sensor can be emitted within the expected range, its operating frequency is generally within 10khz~300khz. When corresponding to this operating frequency range, the radius of the inner hole is approximately between 5um and 1mm.

[0066] In the vibration diaphragm, the thickness of the elastic film 101 ranges from 500nm to 10μm. Based on the operating frequency of the vibration diaphragm, the size of the inner hole, and the sensitivity of the ultrasonic flight sensor, the thickness of the elastic film 101 is 3μm-5μm, which is a more appropriate thickness. The thickness of the first electrode layer 103 in the excitation layer ranges from 50nm to 1μm. Since a piezoelectric layer needs to be formed on the surface of the first electrode layer after the first electrode layer 103 is manufactured, the thickness of the first electrode layer is controlled to be more appropriately between 100nm and 300nm based on comprehensive experiments and test results. The thickness of the second electrode layer 105 ranges from 50nm to 1μm. Considering the resistance value of the second electrode layer and the manufacturing process, the thickness of the second electrode layer 105 is more appropriately controlled to be between 100nm and 200nm. The passivation layer 106 can form a protective layer on the surface of the patterned excitation layer, and protect the patterned excitation layer accordingly, so that it is isolated from the external environment, and the environmental reasons are prevented from affecting the excitation layer. The thickness of the passivation layer 106 is in the range of 10 nm to 1 μm, preferably 100 nm to 300 nm.

[0067] In this embodiment, the interface diagram of the first electrode layer 103, the piezoelectric layer 104 and the second electrode layer 105 in the excitation layer 110 is in the shape of an inverted trapezoid, that is, the area of ​​the first electrode layer 103 is slightly larger than the area of ​​the piezoelectric layer 104, and the area of ​​the piezoelectric layer 104 is slightly larger than the area of ​​the second electrode layer 105. Since the inner hole 120 is formed by forming an opening on the support layer 107 and then inverted on another wafer, the cross-sectional diagram of the excitation layer 110 is in the shape of an inverted trapezoid.

[0068] In this embodiment, the height of the inner hole 120 is greater than the thickness of the excitation layer 110, and the excitation layer 110 is disposed inside the inner hole. The inner hole 120 is formed after the excitation layer 110 is completed, and after the excitation layer is patterned, the support layer 107 is formed, and then the inner hole 120 is formed inside the support layer 107. The excitation layer 110 placed inside the inner hole 120, especially the slightly thicker piezoelectric layer 104 therein, when not patterned, will produce a large difference in stress in the same wafer for making an ultrasonic flight sensor, which can easily lead to the difference in performance between ultrasonic flight sensors made from the same wafer due to stress, resulting in the deviation of their operating frequency exceeding the preset tolerance. Therefore, in order to reduce the drift of the performance of the ultrasonic flight sensor caused by the different stress of the piezoelectric layer material, the excitation layer 110 is patterned, and the area covered by the piezoelectric layer 104 is reduced, which can reduce the influence of the piezoelectric layer stress on the performance of the ultrasonic flight sensor. In this embodiment, the excitation layer 110 is patterned and designed, and part of the piezoelectric layer is removed accordingly, or part of the electrode layer is removed at the same time, thereby reducing the influence of the stress of the piezoelectric layer on the performance of the ultrasonic flight sensor.

[0069] The supporting ribs 110b are symmetrically arranged around the main body 110a of the excitation layer 110, and the supporting ribs 110b extend from the main body 110a to the outer portion of the inner hole 120, and at least one of the supporting ribs 110b extends to the outer portion of the inner hole 120 and enters the support layer 107. The number of the supporting ribs 110b can be, for example, four, one of the supporting ribs 110b extends to the outer portion of the inner hole 120 and enters the support layer 107, and the remaining supporting ribs 110b can be electrically isolated from the main body 110a of the excitation layer 110. As shown in this embodiment, at least one supporting rib 110b is required to serve as the lead-out terminal of the electrode layer of the excitation layer. However, in this illustrated embodiment or other embodiments, the multiple supporting ribs 110b are not used as the lead-out terminals of the excitation layer, and some supporting ribs are not connected to the electrode layer in the excitation layer. The multiple symmetrical supporting rib structures are mainly used to maintain the bending stiffness of the elastic diaphragm composed of the entire excitation layer and the elastic membrane, and to reduce the influence of the residual stress of the piezoelectric layer on the stiffness of the entire elastic diaphragm.

[0070] The elastic membrane 101 is provided with an opening 130. The opening is much smaller than the size of the inner hole. Of course, the position of the opening can be selected to be opened at the position where the excitation layer is removed from the inner wall of the elastic membrane, so that the opening can be avoided from penetrating the excitation layer. The opening 130 is connected to the inner hole. The purpose of the opening is mainly to balance the pressure on both sides of the elastic diaphragm. In other embodiments, the opening 130 does not need to be located at the center of the inner hole 120, and can be opened at other places where the stress of the elastic diaphragm is relatively small.

[0071] The ultrasonic flight sensor provided in this embodiment also includes a first electrical contact hole 108a and a second electrical contact hole 108b disposed on the periphery of the inner hole 120. In this way, an excitation signal is applied to the ultrasonic flight sensor through the first electrical contact hole 108a and the second point contact hole 108b, or an ultrasonic signal received by the ultrasonic flight sensor is received and converted into an electrical signal. The first electrical contact hole 108a and the second electrical contact hole 108b are electrically connected to the first electrode layer 103 and the second electrode layer 105 in the support rib 110b, respectively. For example, the first electrical contact hole 108a and the second electrical contact hole 108b are filled with a conductive material 109 to achieve electrical connection with the first electrode layer 103 and the second electrode layer 105 in the support rib 110b. Figure 1 As shown, the ribs 110b extending to the outer portion of the inner hole 120 enter the support layer 107, lead out the first electrode layer 103 and the second electrode layer 105 in the excitation layer 110, and are electrically connected to the outside through the contact pads (Pad) 140 filled in the first electrical contact holes 108a and the second electrical contact holes 108b.

[0072] In this embodiment Figure 1 The ultrasonic flight sensor shown in the figure leads the electrode in the excitation layer 110 out through a rib 110b. Figure 3 The ultrasonic flight sensor shown in the figure uses two ribs to lead out the first electrode layer and the second electrode layer in the excitation layer 110. In other embodiments of the present invention, the number of ribs used to lead out the electrodes may depend on the specific design, and the present invention does not limit this.

[0073] The above is a brief and clear illustration of the main structure of the ultrasonic flight sensor, and does not clearly or specifically illustrate the structures of other layers included in its actual structure. The ultrasonic flight sensor provided in this embodiment may actually further include: a seed layer disposed between the elastic membrane 101 and the excitation layer 110 to facilitate the growth of the excitation layer 110; a passivation layer 106 disposed on the second electrode layer 105 to protect the excitation layer 110; and an adhesive layer 201 disposed between the semiconductor substrate 200 and the support layer 107 to enhance the adhesive force between the semiconductor substrate 200 and the support layer 107. The above are only examples of possible other layer structures, and are not limited thereto.

[0074] It should be noted that, in order to facilitate the description of the structure of the ultrasonic flight sensor in this embodiment, Figure 1 and Figure 3 The corresponding top view is simplified accordingly. For example, the first electrode 103 is represented by a dotted line, and the elastic film 101, the support layer 107, the passivation layer 106, etc. are not shown.

[0075] In the ultrasonic flight sensor provided in this embodiment, the ultrasonic flight sensor is manufactured by using semiconductor technology, which helps to achieve miniaturization of the ultrasonic flight sensor and reduce the volume of the ultrasonic flight sensor. At the same time, it can help to make the volume of the electronic device integrated with the ultrasonic flight sensor smaller or thinner, thereby improving the integration of the electronic device.

[0076] Embodiment 2

[0077] Figure 3 A top view of a partial structure of an ultrasonic flight sensor provided in this embodiment, Figure 4a for Figure 3 Schematic diagram of the cross-section structure along the CC line, Figure 4b for Figure 3 Schematic diagram of the cross-section structure along line DD; Figure 4c for Figure 3 Schematic diagram of the cross-sectional structure along line EE.

[0078] refer to Figure 3 and Figures 4a to 4cAs shown, the ultrasonic flight sensor provided in this embodiment includes a semiconductor substrate 200, a support layer 107, an elastic film 101 and an excitation layer 110. The support layer 107 is disposed on the surface of the semiconductor substrate 200, and an inner hole 120 is opened in the central area of ​​the support layer 107; the elastic film 101 covers the inner hole 120 and is disposed on the surface of the support layer 107; the excitation layer 110 is disposed in the inner hole 120 and attached to the surface of the elastic film 101 facing the inner hole 120, and the excitation layer 110 includes: a first electrode layer 103, a second electrode layer 105, and a piezoelectric layer 104 disposed between the first electrode layer 103 and the second electrode layer 105.

[0079] The vertical cross-section of the inner hole 120 may be, for example, square or trapezoidal. As described in the first embodiment, the size of the inner hole is determined according to the operating frequency of the ultrasonic flight sensor, and its cross-section is circular. The vertical cross-section of the cavity may be square or trapezoidal, depending on the specific performance of the ultrasonic flight sensor. The height of the cavity of the inner hole 120 is greater than the thickness of the excitation layer contained therein, so that the elastic diaphragm has sufficient vibration amplitude.

[0080] The structure of the ultrasonic flight sensor described in the second embodiment is substantially the same as that described in the first embodiment. The main difference is that: Figure 3 The support ribs shown are only used to lead out the electrodes in the excitation layer and do not have the Figure 1 Some of the rib structures described above are not connected to the electrode layer in the excitation layer and are symmetrically distributed relative to the inner hole. Figure 3 The support ribs shown in FIG. 1 can also be Figure 1 As shown in the figure, a rib is used to extend to the support layer and is used to connect the first electrode layer and the second electrode layer in the patterned excitation layer.

[0081] The excitation layer 101 is patterned. Here is an example of an excitation layer 101 patterning. Figure 3 The main part of the patterned excitation layer 110 is arranged around the central area of ​​the inner hole 120. The first electrode layer 103, the second electrode layer 105 and the piezoelectric layer 104 are patterned in the same or similar shapes, for example, the first electrode layer 103, the second electrode layer 105 and the piezoelectric layer 104 are distributed in a ring shape around the center of the inner hole 120.

[0082] In this embodiment, the elastic membrane 101 is provided with an opening 130, and the opening 130 penetrates the elastic membrane and communicates with the inner hole 120. In this embodiment, the opening 130 is arranged in the central area of ​​the elastic membrane 101 portion corresponding to the inner hole 120. The function of the opening has been described in the first embodiment, so it will not be repeated here. In other embodiments, the opening can also be arranged at a position where there is still an excitation layer inside the elastic membrane. When the opening is arranged, the opening needs to penetrate the elastic membrane and also needs to penetrate the excitation layer portion at the corresponding position of the elastic membrane to communicate with the inner hole. The main part of the patterned excitation layer 110 is arranged around the central area of ​​the inner hole 120. The patterned shapes of the first electrode layer 103, the second electrode layer 105 and the piezoelectric layer 104 are the same or similar, for example, the first electrode layer 103, the second electrode layer 105 and the piezoelectric layer 104 are distributed in a ring shape around the center of the inner hole 120.

[0083] In the ultrasonic flight sensor provided in this embodiment, the excitation layer 110 further includes the first electrode layer 103 and the second electrode layer 105 extending into the support layer 107. The first electrical contact hole 108a and the second electrical contact hole 108b are arranged near the excitation layer 110 extending to the support layer 107. The first electrical contact hole 108a and the second electrical contact hole 108b are filled with a conductive material 109. The conductive material 109 is electrically connected to the first electrode layer 103 and the second electrode layer 105 in the nearby excitation layer 110, respectively, and then the first electrode layer 103 and the second electrode layer 105 are led out through the conductive material 109. For example, a contact pad 140 is arranged on the first electrical contact hole 108a and the second electrical contact hole 108b, and is electrically connected to the outside world (such as an ASIC chip) through the contact pad 140 to perform operations such as signal transmission, reception, and processing.

[0084] Accordingly, this embodiment provides a method for manufacturing an ultrasonic flight sensor. Figure 5 The flowchart of the method for manufacturing the ultrasonic flight sensor provided in this embodiment is as follows: Figure 5 As shown, the manufacturing method of the ultrasonic flight sensor provided in this embodiment includes:

[0085] S01: providing a substrate;

[0086] S02: forming an elastic film on the surface of the substrate;

[0087] S03: manufacturing an excitation layer on the surface of the elastic film, and patterning the excitation layer;

[0088] S04: forming a support layer on the surface of the substrate having the excitation layer formed thereon;

[0089] S05: opening an inner hole in the supporting layer;

[0090] S06: providing a wafer;

[0091] S07: placing the substrate having a support layer with inner holes invertedly on the wafer; and

[0092] S08: removing the substrate.

[0093] Figures 6a to 6k The following is a schematic diagram of the corresponding steps of the method for manufacturing the ultrasonic flight sensor provided in this embodiment. Figure 5 and Figures 6a to 6k The method for manufacturing the ultrasonic flight sensor provided in this embodiment is further described in detail.

[0094] refer to Figure 6a As shown, step S01 is performed to provide a substrate 100. For compatibility with subsequent semiconductor processes, the substrate 100 can be made of a wafer. Basically, any material suitable for a wafer can be used. Therefore, the substrate 100 can be at least one of the following materials: Si, Ge, SiGe, SiC, SiGeC, InAs, GaAs, InP or other III / V compounds. The substrate 100 can also include a multilayer structure composed of these materials, or a silicon on insulator (SOI), a stacked silicon on an insulator (SSOI), a stacked silicon germanium on an insulator (S-SiGeOI), a silicon germanium on an insulator (SiGeOI) and a germanium on an insulator (GeO). In this manufacturing method, it should be understood that the substrate is provided, because it is not necessary to dope the substrate to manufacture a semiconductor device, and it is only used as a carrier from beginning to end. Therefore, it is only necessary that the carrier be compatible with the semiconductor process, and it is not limited to using a wafer as a carrier, and other materials can also be used. For example, a carrier such as ceramic, glass or organic material can also be used.

[0095] refer to Figures 6a to 6d As shown, step S02 and step S03 are performed to form an elastic film 101 on the surface of the substrate 100, to form an excitation layer 110 on the surface of the elastic film 101, and to pattern the excitation layer 110. A seed layer 102 is formed between the elastic film 101 and the excitation layer 110 as a transition layer between the two to enhance the bonding force between the two. The excitation layer 110 includes a first electrode layer 103, a piezoelectric layer 104, and a second electrode layer 105 formed sequentially on the elastic film 101. Of course, a passivation layer 106 can also be formed on the excitation layer 110 to protect the excitation layer 110.

[0096] The following specific production method is taken as an example to further describe and illustrate the production method.

[0097] For details, please refer to Figures 6a to 6kThe simplified schematic diagram does not cover all the steps in the actual production process. Figure 6a As shown, an elastic film 101 and a first electrode layer 103 are sequentially deposited on the surface of the substrate 100, and then, as shown in FIG. Figure 6b As shown, the first electrode layer 103 is patterned to etch the first electrode layer 103 into a certain shape.

[0098] Then, if Figure 6c As shown, a piezoelectric layer 104 , a second electrode layer 105 and a passivation layer 106 are sequentially deposited on the elastic film 101 .

[0099] Then, if Figure 6d As shown, the passivation layer 106 , the second electrode layer 105 and the piezoelectric layer 106 are etched in sequence to pattern the excitation layer 110 .

[0100] The same photomask may be used to etch the passivation layer 106, the second electrode layer 105, and the piezoelectric layer, so that the passivation layer only covers the surface of the second electrode layer 105. Of course, in other embodiments of the manufacturing method, the passivation layer 106 may be formed after the second electrode layer 105 and the piezoelectric layer 106 are etched, so that the passivation layer 106 can cover the surface of the patterned excitation layer 110, thereby providing more comprehensive protection for the excitation layer 110.

[0101] After patterning the excitation layer 110, the shapes of the first electrode layer 103, the piezoelectric layer 104, and the second electrode layer 105 are the same or similar. In other embodiments of the present invention, the excitation layer 110 may also be formed by sequentially forming the first electrode layer 103, the piezoelectric layer 104, and the second electrode layer 105, and then sequentially patterning the first electrode layer 103, the piezoelectric layer 104, and the second electrode layer 105. In the semiconductor manufacturing process exemplified here, the excitation layer is mainly patterned by an etching process.

[0102] In this embodiment, the material of the elastic film 101 can be silicon (Si), silicon dioxide (SiO2) or silicon nitride (Si3N4). The material of the first electrode layer 103 can be molybdenum (Mo), platinum (Pt), aluminum (Al) or gold (Au). The second electrode layer 105 and the first electrode layer 103 can be made of the same material or different materials. The thickness of each layer has been described in the above content and will not be repeated here.

[0103] The material of the piezoelectric layer 104 can be aluminum nitride (AlN), aluminum nitride doped with scandium (Sc), or x Al 1-xN), zinc oxide (ZnO), lead zirconate titanate piezoelectric ceramics (PZT), lead zirconate titanate piezoelectric ceramics doped with other elements (such as PLZT, PNZT), lead magnesium niobate-lead titanate (PMN-PT) or KNN-based ceramics. The material of the passivation layer 106 can be selected from aluminum nitride (AlN), silicon (Si), silicon dioxide (SiO2) or silicon nitride (Si3N4). In this embodiment, the material of the elastic film 101 is silicon dioxide (SiO2), the material of the seed layer 102 is aluminum nitride (AlN), the first electrode layer 103 and the second electrode layer 105 are molybdenum (Mo), the material of the piezoelectric layer 104 is aluminum nitride (AlN), and the material of the passivation layer 104 is aluminum nitride (AlN).

[0104] refer to Figure 6e and Figure 6f As shown, step S04 and step S05 are performed to form a support layer 107 on the surface of the substrate 100 on which the excitation layer 110 is formed, and an inner hole 120 is opened in the support layer 107 .

[0105] First, if Figure 6e As shown in FIG. 1 , a support layer 107 is formed on the patterned excitation layer 110 and the elastic film 101, and the thickness of the support layer 107 is greater than the thickness of the excitation layer 110; then, as shown in FIG. Figure 6f As shown, the support layer 107 is etched to expose the surface of the excitation layer 110 and part of the elastic film 101, so as to form an inner hole 120 in the support layer 107. The support layer 107 can be a dry film, which is a photoresist film with adhesiveness used in semiconductor chip packaging or printed circuit board manufacturing, usually a photosensitive polymer material, such as polyimide (PI), benzocyclobutene (BCB: bis-Benzo CycloButene), poly (p-phenylene-2,6-Benzo bis Oxazole) (PBO: P-phenylene-2,6-Benzo bis Oxazole), etc. Accordingly, the inner hole 120 can be formed in the support layer 107 by exposure and development treatment.

[0106] refer to Figure 6g to Figure 6h As shown, step S06, step S07 and step S08 are performed to provide a wafer 200, and the substrate 100 having the support layer 107 with the inner hole 120 is placed upside down on the wafer 200, and then the substrate 100 is removed.

[0107] Specifically, first, a wafer 200 is provided, and the material of the wafer 200 can be the same as or different from that of the substrate 100; then, Figure 6gAs shown, the substrate 100 where the support layer 107 with the inner hole 120 is located is inverted on the wafer 200. The inner hole 120 with the support layer 107 and the wafer 200 form a closed cavity. Figure 6h As shown, the substrate 100 is removed to expose the elastic film 101. If the substrate is made of a wafer material, it can be removed or separated by etching, chemical mechanical polishing (CMP) or other methods.

[0108] In this embodiment, before the substrate 100 is inverted on the wafer 200, a bonding layer 201 is formed on the side of the wafer 200 that contacts the support layer 107. The material of the bonding layer 201 can be silicon dioxide (SiO2), for example. The thickness of the bonding layer 201 is 1 μm-3 μm, preferably 1 μm-2 μm.

[0109] refer to Figure 6i to Figure 6k As shown, the method for manufacturing an ultrasonic flight sensor provided in this embodiment also includes the following steps: making a first electrical contact hole 108a and a second electrical contact hole 108b on the elastic membrane 101 extending to the support layer portion and the excitation layer 110, and filling the first electrical contact hole 108a and the second electrical contact hole 108b with a conductive material 109.

[0110] First, the elastic film 101 extending to the support layer is etched to expose the first electrode layer 103. Figure 6i As shown;

[0111] Next, the excitation layer 110 (the first electrode layer 103 and the piezoelectric layer 104) extending to the support layer is etched to expose the second electrode layer 105. Figure 6j shown.

[0112] Next, a conductive material 109 is filled into the first electrical contact hole 108a and the second electrical contact hole 108b, so that the first electrical contact hole 108a is electrically connected to the first electrode layer 103, and the second electrical contact hole 108b is electrically connected to the second electrode layer 105. In this embodiment, the conductive material 109 may be, for example, aluminum (Al), distributed on the bottom and sidewalls of the first electrical contact hole 108a and the second electrical contact hole 108b to achieve electrical connection with the first electrode layer 103 and the second electrode layer 105, as shown in FIG. Figure 6k shown.

[0113] Continue to refer Figure 6i and Figure 6jAs shown, the manufacturing method of the ultrasonic flight sensor provided in this embodiment also includes making an opening 130 in the portion of the elastic film 101 covering the inner hole 120, so that the inner hole 120 has the same air pressure as the external air. The making of the opening 130 can be performed after the making of the first electrical contact hole 108a and the second electrical contact hole 108b; in this way, impurities or contaminants are prevented from entering the cavity of the inner hole through the opening 130. Of course, in other manufacturing methods, when the above-described problem does not occur, it can also be completed in the same step as the first electrical contact hole 108a and the second electrical contact hole 108b, and the present invention is not limited to this.

[0114] It should be noted that, in order to more briefly and clearly illustrate the structure and manufacturing method of the present invention, the manufacturing method or structure of the ultrasonic flight sensor provided by the present invention omits necessary or unnecessary transition layers between layers. For example, a seed layer 102 is also formed between the elastic membrane 101 and the first electrode layer 103.

[0115] Embodiment 3

[0116] This embodiment provides an ultrasonic flight sensor and a manufacturing method thereof. Figure 7j The cross-sectional diagram of the ultrasonic flight sensor provided in this embodiment is shown in FIG. Figure 7j As shown, the difference between the ultrasonic flight sensor provided in this embodiment and the second embodiment is that a corresponding driving control circuit is provided on the wafer 200, that is, the control chip driving and controlling the ultrasonic flight sensor is made on the wafer 200. The driving control circuit includes a first contact pad 140a and a second contact pad 140b. The first electrical contact hole 108a and the second electrical contact hole 108b penetrate the support layer 107; the first electrical contact hole 108a and the second electrical contact hole 108b are filled with a conductive material 109 to electrically connect the first electrical contact hole 108a and the second electrical contact hole 108b with the first contact pad 140a and the second contact pad 140b respectively. That is, through the conductive material 109, the first electrode layer 103 and the second electrode layer 105 are electrically connected with the first contact pad 140a and the second contact pad 140b respectively, so that the ultrasonic flight sensor and the driving control circuit are integrated on the same semiconductor substrate. In this way, the ultrasonic flight sensor is avoided from being electrically connected as a single chip through wire bond, thereby reducing the horizontal size occupied by the entire ultrasonic flight sensor module.

[0117] Figures 7a to 7j This is a schematic diagram of the corresponding steps of the method for manufacturing the ultrasonic flight sensor provided in this embodiment. Figures 7a to 7j As shown, the manufacturing method of the ultrasonic flight sensor provided in this embodiment includes the following steps:

[0118] First, refer to Figures 7a to 7d As shown, a substrate 100 is provided, an elastic film 101 is formed on the surface of the substrate 100, and an excitation layer 110 is formed on the surface of the elastic film 101. The excitation layer 110 includes a first electrode layer 103, a second electrode layer 105, and a piezoelectric layer located between the first electrode layer 103 and the second electrode layer 105. Then, the excitation layer 110 is patterned. For details, please refer to Example 2.

[0119] Next, refer to Figure 7e and Figure 7f As shown, a support layer 107 is manufactured on the surface of a substrate 100 on which an excitation layer 110 is manufactured, and an inner hole 120, a first opening 108a′ and a second opening 108b′ are opened in the support layer 107. The positions of the first opening 108a′ and the second opening 108b′ correspond one-to-one to the first contact pad 140a and the second contact pad 140b in the driving circuit on the subsequently bonded wafer (semiconductor substrate) 200. Of course, in other embodiments of the manufacturing method, the first opening 108a′ or the second opening 108b′ may not need to be manufactured here. For example, the first opening 108a′ and the second opening 108b′ may be manufactured when the first electrical contact hole and the second electrical contact hole are manufactured in the subsequent process. Next, referring to Figure 7g to Figure 7h As shown, a wafer 200 is provided, the substrate 100 is placed upside down on the wafer 200, and the substrate 100 is removed. A driving circuit is arranged on the wafer 200, and the driving circuit includes a first contact pad 140a and a second contact pad 140b. An adhesive layer 201 may also be arranged on the wafer 200 to enhance the adhesive force between the wafer 200 and the substrate 100.

[0120] Next, refer to Figure 7i and Figure 7jAs shown, a first electrical contact hole 108a and a second electrical contact hole 108b are formed on the elastic film 101 extending to the supporting layer and the excitation layer 110. First, the elastic film 101 extending to the supporting layer, the excitation layer 110 and the bonding layer 201 are etched until they are connected to the first opening 108a′ and the second opening 108b′, so as to form the first electrical contact hole 108a and the second electrical contact hole 108b, and expose a part of the first electrode layer 103 and a part of the second electrode layer 105; then, a conductive material 109 is filled into the first electrical contact hole 108a and the second electrical contact hole 108b, so that the first electrical contact hole 108a is electrically connected to the first electrode layer 103, and the second electrical contact hole 108b is electrically connected to the second electrode layer 105, and then the first electrode layer 103 and the first contact pad 140a are electrically connected, and the second electrode layer 105 and the second contact pad 140b are electrically connected through the conductive material 109.

[0121] Continue to refer Figure 7i and Figure 7j As shown, the manufacturing method of the ultrasonic flight sensor provided in this embodiment further includes manufacturing an opening 130 in the portion of the elastic film 101 covering the inner hole 120, so that the inner hole 120 has the same air pressure as the external air. The manufacturing of the opening 130 can be performed after manufacturing the first electrical contact hole 108a and the second electrical contact hole 108b, or can be completed in the same step as the first electrical contact hole 108a and the second electrical contact hole 108b, and the present invention is not limited to this.

[0122] It should be understood that in this third embodiment, only a manufacturing method of a structure corresponding to the ultrasonic flight sensor and its module is provided in schematic form, and this manufacturing method is not used to limit the order of the various process steps used to manufacture the structure and the specific steps included in each process step.

[0123] Embodiment 4

[0124] This embodiment provides an ultrasonic flight sensor and a method for manufacturing the same. Figure 8j This is a schematic diagram of the cross-sectional structure of the ultrasonic flight sensor provided in this embodiment. Figure 8jAs shown, the difference between the ultrasonic flight sensor provided in this embodiment and the second embodiment is that the edge position of the inner hole 120 contacting the support layer 107 of the elastic membrane 101 is concave toward the support layer 107 by a preset distance to form a regular-shaped hole eaves 120a. Since in the above-mentioned embodiments, the inner hole 120 is formed in the support layer 107, due to the limitation of the semiconductor manufacturing process, the edge shape of the inner hole 120 formed in the support layer 107 is difficult to be regular. Or even if the edge shape of the inner hole 120 in the formed support layer 107 is barely acceptable, it will be easily deformed due to the subsequent manufacturing process. If the elastic membrane 101 of the ultrasonic flight sensor finally covers the edge part of the inner hole 120, due to the irregular shape of the edge part of the inner hole 120, it is very easy to make the difference in working frequency between the ultrasonic flight sensors formed in the same wafer become more serious, and even the working frequency or performance of the manufactured ultrasonic flight sensor fails to meet the expected requirements.

[0125] Figures 8a to 8l This is a schematic diagram of the corresponding steps of the method for manufacturing the ultrasonic flight sensor provided in this embodiment. Figures 8a to 8l As shown, the manufacturing method of the ultrasonic flight sensor provided in this embodiment includes the following steps:

[0126] First, refer to Figures 8a to 8d As shown, a substrate 100 is provided, and an elastic film 101 is formed on the surface of the substrate 100. An excitation layer 110 is formed on the surface of the elastic film 101, and the excitation layer includes a first electrode layer 103, a second electrode layer 105, and a piezoelectric layer located between the first electrode layer 103 and the second electrode layer 105. Then, the excitation layer 110 is patterned. For details, please refer to the second embodiment.

[0127] Next, refer to Figure 8e As shown, after patterning the excitation layer 110, a cave eaves support body 111 is made on the elastic film 101. Since the junction of the inner hole 120 and the elastic film 101 may be deformed when or after the substrate 100 is bonded to the wafer 200, this will affect the irregular shape of the junction of the inner hole 120 and the elastic film 101, thereby affecting the performance of the ultrasonic flight sensor; or to avoid the irregular edge of the inner hole when the inner hole is formed in the support layer, the cave eaves support body 111 is provided in this embodiment. Since the cave eaves support body 111 plays a supporting role for the cave eaves of the inner hole, the deformation of the cave eaves position caused by the subsequent process is avoided. In the subsequent process that has little effect on the shape of the cave eaves, the cave eaves support body 111 can be released. After releasing the cave eaves support body 111, the cave eaves of the inner hole 120 is a regular shape reserved for it by the cave eaves support body 111. In this embodiment, the material of the cave eaves support body 111 can be selected from silicon, and other materials can also be selected in other embodiments of the present invention.

[0128] Next, refer to Figure 8f and Figure 8g As shown, a support layer 107 is made on the surface of the substrate 100 with the excitation layer 110 and the cave eave support body 111, and an inner hole 120 is opened in the support layer 107. After the inner hole 120 is opened, the support layer 107 at least partially contacts the cave eave support body 111.

[0129] Next, refer to Figure 8h and Figure 8i As shown, a wafer 200 is provided, the substrate 100 is placed upside down on the wafer 200, and the substrate 100 is removed. For details, please refer to the first embodiment.

[0130] Next, refer to Figure 8j and Figure 8k As shown, a first electrical contact hole 108a and a second electrical contact hole 108b are made on the elastic film 101 extending to the support layer portion and the excitation layer 110, exposing a portion of the first electrode layer 103 and a portion of the second electrode layer 105, and then, a conductive material 109 is filled into the first electrical contact hole 108a and the second electrical contact hole 108b, so that the first electrical contact hole 108a is electrically connected to the first electrode layer 103, and the second electrical contact hole 108b is electrically connected to the second electrode layer 105.

[0131] Continue to refer Figure 8j and Figure 8k As shown, the manufacturing method of the ultrasonic flight sensor provided in this embodiment further includes manufacturing an opening 130 in the portion of the elastic film 101 covering the inner hole 120, so that the inner hole 120 has the same air pressure as the external air. The manufacturing of the opening 130 can be performed after manufacturing the first electrical contact hole 108a and the second electrical contact hole 108b, or can be completed in the same step as the first electrical contact hole 108a and the second electrical contact hole 108b, and the present invention is not limited to this.

[0132] Next, refer to Figure 8l As shown, the cave eaves support body 111 is removed, so that the edge position of the inner hole 120 contacting the support layer 107 of the elastic membrane 101 is concave toward the support layer 107 by a preset distance to form a cave eaves 120a of a regular shape. In this embodiment, the material of the cave eaves support body 111 can be silicon, for example, the cave eaves support body 111 can be removed by using a xenon difluoride (XeF2) vapor phase etching method. In other embodiments of the present invention, the cave eaves support body 111 can also be made of other materials and can be removed with a corresponding release agent.

[0133] It is understood that the fourth embodiment focuses on a method for making regular inner hole eaves, and the fourth embodiment does not limit the method for making regular eaves. The fourth embodiment only shows a method for making a structure corresponding to an ultrasonic flight sensor and its module, and does not use this method to limit the order of the various processes used to make the structure and the specific steps included in each process.

[0134] In summary, the present invention provides an ultrasonic flight sensor and a manufacturing method thereof, comprising a semiconductor substrate, a support layer disposed on the surface of the semiconductor substrate and having an inner hole, an elastic film covering the inner hole and disposed on the surface of the support layer, and an excitation layer disposed in the inner hole and attached to the surface of the elastic film facing the inner hole, wherein the elastic film is provided with an opening, the opening passes through the excitation layer and is connected to the inner hole, and the excitation layer comprises a first electrode layer, a second electrode layer, and a piezoelectric layer disposed between the first electrode layer and the second electrode layer. The present invention adopts semiconductor technology to manufacture the ultrasonic flight sensor, realizes miniaturization and easy integration of the ultrasonic flight sensor, and helps the electronic equipment using the ultrasonic sensor to realize miniaturization and thinness.

[0135] Furthermore, in the present invention, the excitation layer is patterned and designed, and part of the piezoelectric layer material is removed, thereby reducing the influence of the piezoelectric layer stress on the performance of the ultrasonic flight sensor, and helping to improve the performance of the miniaturized ultrasonic flight sensor.

[0136] Furthermore, in the process of manufacturing the ultrasonic flight sensor, after patterning the excitation layer, a hole eaves support body is made on the elastic membrane to reduce the subsequent deformation of the bonding point between the support layer and the elastic membrane, thereby weakening or even avoiding the influence of the deformation at the bonding point between the support layer and the elastic membrane on the performance of the ultrasonic flight sensor.

[0137] It should be noted that the various embodiments in this specification are described in a related manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the structural embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0138] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. An ultrasonic flight sensor, characterized in that: The ultrasonic flight sensor is manufactured using semiconductor technology and comprises: Semiconductor substrate; A support layer is disposed on the surface of the semiconductor substrate and has an inner hole; An elastic membrane, covering the inner hole and disposed on the surface of the supporting layer; The excitation layer is disposed in the inner hole and attached to the surface of the elastic film facing the inner hole; wherein, The excitation layer is patterned, the main body of the excitation layer is arranged in the inner hole and around the central area of ​​the inner hole, and the excitation layer includes: a first electrode layer, a second electrode layer and a piezoelectric layer arranged between the first electrode layer and the second electrode layer.

2. The ultrasonic flight sensor according to claim 1, characterized in that: The patterned shapes of the first electrode layer, the second electrode layer and the piezoelectric layer are the same or similar.

3. The ultrasonic flight sensor according to claim 1, characterized in that: The elastic film is provided with an opening, and the opening passes through the excitation layer and is communicated with the inner hole.

4. The ultrasonic flight sensor according to claim 3, characterized in that: The opening is arranged in the central area of ​​the elastic membrane portion corresponding to the inner hole.

5. The ultrasonic flight sensor according to claim 3, characterized in that: The main body of the excitation layer is arranged around the opening.

6. The ultrasonic flight sensor according to claim 5, characterized in that: At least two supporting ribs are symmetrically arranged around the main body of the excitation layer, and the supporting ribs extend from the main body to the peripheral portion of the inner hole.

7. The ultrasonic flight sensor according to claim 6, characterized in that: At least one of the ribs extends to a peripheral portion of the inner hole and enters the support layer.

8. The ultrasonic flight sensor according to claim 7, characterized in that: It also includes a first electrical contact hole and a second electrical contact hole arranged at the periphery of the inner hole; the first electrical contact hole and the second electrical contact hole are electrically connected to the first electrode layer and the second electrode layer in the rib respectively.

9. The ultrasonic flight sensor according to claim 1, characterized in that: The excitation layer further includes the first electrode layer and the second electrode layer extending into the support layer.

10. The ultrasonic flight sensor according to claim 9, characterized in that: It also includes a first electrical contact hole and a second electrical contact hole arranged near the excitation layer extending to the support layer; the first electrical contact hole and the second electrical contact hole are filled with conductive materials and are electrically connected to the first electrode layer and the second electrode layer in the nearby excitation layer respectively.

11. The ultrasonic flight sensor according to claim 1, characterized in that: The edge position of the inner hole contacting the supporting layer of the elastic membrane is recessed toward the supporting layer by a preset distance to form a hole eave of a regular shape.

12. A method for manufacturing an ultrasonic flight sensor, characterized in that: include: providing a substrate; forming an elastic film on the surface of the substrate; Making an excitation layer on the surface of the elastic film and patterning the excitation layer; Making a support layer on the surface of the substrate on which the excitation layer is made; Opening an inner hole in the support layer; providing a wafer; Place a substrate having a support layer with inner holes invertedly on the wafer; as well as removing the substrate; Wherein, the main body of the excitation layer is arranged in the inner hole and around the central area of ​​the inner hole.

13. The method for manufacturing an ultrasonic flight sensor according to claim 12, characterized in that: The production incentive layer comprises: manufacturing a first electrode layer; Fabricating a piezoelectric layer on the fabricated first electrode layer; A second electrode layer is fabricated on the fabricated piezoelectric layer.

14. The method for manufacturing the ultrasonic flight sensor according to claim 13, characterized in that: Also includes: The first electrode layer, the piezoelectric layer and the second electrode layer after patterning have the same or similar shapes.

15. The method for manufacturing an ultrasonic flight sensor according to claim 14, characterized in that: The method also includes manufacturing a cave eaves support body on the elastic film after patterning the excitation layer.

16. The method for manufacturing the ultrasonic flight sensor according to claim 15, characterized in that: It also includes removing the cave eaves support body.

17. The method for manufacturing an ultrasonic flight sensor according to claim 12, characterized in that: The method also includes making an opening in the portion of the elastic film covering the inner hole after removing the substrate.

18. The method for manufacturing an ultrasonic flight sensor according to claim 13, characterized in that: The method also includes forming a first electrical contact hole and a second electrical contact hole on the elastic film extending to the support layer portion and the excitation layer.

19. The manufacturing method according to claim 18, characterized in that: A corresponding driving circuit is arranged on the wafer, and the driving circuit includes a first contact pad and a second contact pad.

20. The manufacturing method according to claim 19, characterized in that: The first electrical contact hole and the second electrical contact hole penetrate the support layer; the first electrical contact hole and the second electrical contact hole are filled with conductive materials to electrically connect the first electrical contact hole and the second electrical contact hole to the first contact pad and the second contact pad respectively.

21. The method according to claim 18, characterized in that: The method further includes filling the first electrical contact hole and the second electrical contact hole with a conductive material, so that the first electrical contact hole is electrically connected to the first electrode layer, and the second electrical contact hole is electrically connected to the second electrode layer.

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