Ultrasonic transducer and method for manufacturing same

Abstract

The invention provides an ultrasonic transducer. The ultrasonic transducer comprises a substrate and a plurality of ultrasonic transduction units, the substrate is provided with an ultrasonic transceiving area. The plurality of ultrasonic transduction units are arranged on the substrate at intervals along a first direction, and each ultrasonic transduction unit comprises a first electrode, a plurality of first cavities and a second electrode. The first electrode and the plurality of first cavities are arranged in the ultrasonic transceiving area, and the first cavities are overlapped on the first electrode. The first cavities are arranged at intervals along the second direction. The second electrode extends on the first cavities along the second direction and overlaps the first electrode and the first cavities. The second electrode is electrically insulated from the first electrode. The second electrode has a first width along the first direction in the ultrasonic transceiving region, and the first width of the second electrode remains unchanged along the second direction. The invention also provides a manufacturing method of the ultrasonic transducer.

Description

Technical Field

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

[0002] Ultrasonic transducers are transducers that can realize the mutual conversion between sound energy and electrical energy within the ultrasonic frequency range. Ultrasonic transducers can be mainly divided into three categories: 1. Transmitter; 2. Receiver; and 3. Transceiver. The transducer used to transmit ultrasonic waves is called a transmitter. When the transducer is in the transmitting state, it converts electrical energy into mechanical energy and then into sound energy. The transducer used to receive sound waves is called a receiver. When the transducer is in the receiving state, it converts sound energy into mechanical energy and then into electrical energy. In some cases, the transducer can be used as both a transmitter and a receiver, which is called a transceiver. Transceiver is the core content and one of the key technologies of ultrasonic technology. It is widely used in non-destructive testing, medical imaging, ultrasonic microscopy, fingerprint recognition and the Internet of Things.

[0003] In order to obtain a better operating bandwidth, a method of forming a vibration cavity using a sacrificial layer in combination with etching technology has been proposed. Since the sacrificial layer is also covered with a driving electrode layer, the driving electrode layer must be provided with holes in order to etch the sacrificial layer. In addition, due to the limitations of the etching process capabilities, the spacing between the holes on the driving electrode layer cannot be too large, resulting in the need for a series-parallel wire design for the wire structure of the driving electrode layer in the ultrasonic transceiver area. However, the difference between the overall line width and the signal routing width in the routing area of ​​this type of wire design is too large, and the electrical signal is prone to invalid interface reflections at the interface between the signal routing and the wire, resulting in low sensitivity of the ultrasonic transducer.

[0004] Therefore, it is necessary to design a new type of ultrasonic transducer and a manufacturing method thereof to overcome the above-mentioned defects. Summary of the invention

[0005] The object of the present invention is to provide an ultrasonic transducer with better operating sensitivity. The present invention also provides a method for manufacturing an ultrasonic transducer, wherein the ultrasonic transducer has better sensitivity and operating bandwidth.

[0006] To achieve the above object, the present invention provides an ultrasonic transducer and a method for manufacturing the same. The ultrasonic transducer comprises a substrate having an ultrasonic transceiver area; and

[0007] A plurality of ultrasonic transducer units are arranged on the substrate at intervals along a first direction, and each ultrasonic transducer unit comprises:

[0008] A first electrode is disposed in the ultrasonic wave transceiving area;

[0009] A plurality of first cavities are disposed in the ultrasonic transceiver region and overlap the first electrode, the plurality of first cavities are arranged at intervals along a second direction, and the second direction intersects the first direction; and

[0010] The second electrode extends along the second direction on the multiple first cavities, overlaps the first electrode and the multiple first cavities, and is electrically insulated from the first electrode. The second electrode has a first width along the first direction in the ultrasonic transceiver area, and the first width of the second electrode remains unchanged along the second direction.

[0011] Preferably, each of the first cavities has a cavity width along the first direction, and the first width of the second electrode is greater than or equal to the cavity width.

[0012] Preferably, the second electrode also extends along the first direction on at least two first cavities.

[0013] Preferably, the second electrode has a plurality of through holes, and the plurality of through holes do not overlap the plurality of first cavities; the plurality of through holes are used to form a second cavity connected to at least one adjacent first cavity, and fillers are filled into the plurality of through holes to form a sealing unit.

[0014] Preferably, each of the ultrasonic transducer units further comprises an insulating layer disposed between the first electrode and the second electrode, the insulating layer having a spacing segment separating any two adjacent ones of the plurality of first cavities, and the first cavity is surrounded by adjacent the spacing segments and adjacent the sealing units.

[0015] Preferably, each of the ultrasonic transducer units further comprises:

[0016] A first insulating layer is disposed between the first electrode and the second electrode, the first insulating layer having a plurality of openings, the plurality of openings respectively overlapping the plurality of through holes of the second electrode; and

[0017] The second insulating layer is disposed on the second electrode, and the second insulating layer is also filled into the plurality of through holes of the second electrode and the plurality of openings of the first insulating layer to form the sealing unit.

[0018] Preferably, each ultrasonic transducer unit also includes an insulating layer disposed between the first electrode and the second electrode, the insulating layer having a plurality of openings that do not overlap with the plurality of first cavities, wherein the plurality of openings are used to form a second cavity that is connected to at least one adjacent first cavity, and the second electrode is filled into the plurality of openings of the insulating layer to form a sealing unit.

[0019] Preferably, the orthographic projections of the plurality of first cavities on the substrate are located within the orthographic projection of the second electrode on the substrate.

[0020] Preferably, the substrate further has a routing area outside the ultrasonic transceiver area, the routing area has a signal routing extending from the second electrode, the signal routing has a second width along the first direction, and the second width is less than or equal to the first width.

[0021] Preferably, the signal routing includes:

[0022] an extension portion connected to the second electrode; and

[0023] The connecting portion is connected to the extending portion, and the width of the connecting portion along the first direction gradually decreases from one end connected to the second electrode to the other end connected to the extending portion.

[0024] Preferably, a method for manufacturing an ultrasonic transducer, wherein the ultrasonic transducer comprises a plurality of ultrasonic transducer units, each of the ultrasonic transducer units comprises overlapping first electrodes, a plurality of first cavities and a second electrode, the plurality of ultrasonic transducer units are arranged at intervals along a first direction, the plurality of first cavities are arranged at intervals along a second direction, and the second direction intersects the first direction, the method for manufacturing the ultrasonic transducer comprises:

[0025] forming a first electrode and a plurality of first cavities on a substrate; and

[0026] A second electrode is formed on the plurality of first cavities, wherein the second electrode extends in the second direction and is electrically insulated from the first electrode, and has a first width along the first direction, and the first width of the second electrode remains unchanged along the second direction.

[0027] Preferably, the step of forming the plurality of first cavities comprises:

[0028] forming a sacrificial layer on the first electrode; and

[0029] The sacrificial layer is removed through the plurality of through holes of the second electrode to form the plurality of first cavities, wherein the plurality of through holes of the second electrode do not overlap the plurality of first cavities, and the through holes communicate with at least one adjacent first cavity.

[0030] Preferably, the method for manufacturing an ultrasonic transducer further comprises:

[0031] forming a first insulating layer on the sacrificial layer;

[0032] forming the second electrode on the first insulating layer;

[0033] Before removing the sacrificial layer, removing a portion of the first insulating layer through the plurality of through holes of the second electrode to form a plurality of openings; and

[0034] A second insulating layer is formed on the second electrode, and the second insulating layer is also filled into the plurality of through holes of the second electrode and the plurality of openings of the first insulating layer to form a sealing unit.

[0035] Preferably, the step of forming the plurality of first cavities comprises:

[0036] forming a sacrificial layer on the first electrode;

[0037] forming an insulating layer having a plurality of openings on the sacrificial layer; and

[0038] removing the sacrificial layer through the plurality of openings in the insulating layer to form the plurality of first cavities;

[0039] The second electrode is formed on the insulating layer, and the second electrode is also filled into the plurality of openings to form a sealing unit.

[0040] Preferably, the step of forming the plurality of first cavities comprises:

[0041] forming a sacrificial layer on the first electrode;

[0042] forming an insulating layer on the sacrificial layer; and

[0043] The sacrificial layer is removed to form the plurality of first cavities and to expose a plurality of spacing segments separating the plurality of first cavities in the insulating layer, wherein the orthographic projections of the plurality of spacing segments on the substrate are located within the orthographic projections of the second electrode on the substrate.

[0044] Preferably, each of the plurality of ultrasonic transducer units further comprises a plurality of second cavities, and the plurality of second cavities are used to communicate with at least one adjacent first cavity, and the method for manufacturing the ultrasonic transducer further comprises:

[0045] forming a sacrificial layer on the first electrode;

[0046] forming an insulating layer on the sacrificial layer; and

[0047] The sacrificial layer is removed to form the first cavities and the second cavities, and a plurality of spacers separating the first cavities and the second cavities are exposed in the insulating layer, wherein the orthographic projections of the spacers on the substrate are within the orthographic projections of the second electrode on the substrate.

[0048] Compared with the prior art, in the ultrasonic transducer provided by the present invention, a plurality of ultrasonic transducer units arranged in an ultrasonic transceiver area of ​​a substrate along a first direction are each provided with a first electrode, a plurality of first cavities and a second electrode arranged in an overlapping manner. These first cavities are arranged in an interval along the second direction. The second electrode extending on these first cavities has a first width along the first direction. Since the first width of the second electrode remains unchanged in the extension direction of the second electrode, the invalid interface reflection when the electrical signal is transmitted in the second electrode can be effectively suppressed, which helps to improve the sensitivity of the ultrasonic transducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 is a front view schematic diagram of an ultrasonic transducer according to a first embodiment of the present invention;

[0050] Figure 2 yes Figure 1 An enlarged schematic diagram of a local area Z1 of an ultrasonic transducer;

[0051] Figure 3 yes Figure 2 A cross-sectional schematic diagram of an ultrasonic transducer;

[0052] FIG. 4A to FIG. 4E yes Figure 3 A cross-sectional schematic diagram of a manufacturing process of an ultrasonic transducer;

[0053] Figure 5 is a front view schematic diagram of an ultrasonic transducer according to a second embodiment of the present invention;

[0054] Figure 6 is a front view schematic diagram of an ultrasonic transducer according to a third embodiment of the present invention;

[0055] Figure 7 is a front view schematic diagram of an ultrasonic transducer according to a fourth embodiment of the present invention;

[0056] Figure 8 yes Figure 7 A cross-sectional schematic diagram of an ultrasonic transducer;

[0057] 9A to 9C yes Figure 8 A cross-sectional schematic diagram of a manufacturing process of an ultrasonic transducer;

[0058] Fig.10 is a schematic front view of an ultrasonic transducer according to a fifth embodiment of the present invention. DETAILED DESCRIPTION

[0059] In order to provide a further understanding of the purpose, structure, features, and functions of the present invention, the following detailed description is given in conjunction with the embodiments.

[0060] Certain words are used in the specification and claims to refer to specific components. Those with ordinary knowledge in the field should understand that manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but rather use differences in components' functions as the criteria for distinction. The term "including" mentioned throughout the specification and claims is an open-ended term and should be interpreted as "including but not limited to".

[0061] As used herein, "about", "approximately", "essentially", or "substantially" include the stated value and the average value within an acceptable deviation range of the particular value determined by one of ordinary skill in the art, taking into account the measurement in question and the particular amount of error associated with the measurement (i.e., the limitations of the measurement system). For example, "about" can mean within one or more standard deviations of the stated value, or within, for example, ±30%, ±20%, ±15%, ±10%, ±5%. Furthermore, as used herein, "about", "approximately", "essentially", or "substantially" can select a more acceptable deviation range or standard deviation depending on the measured property, cutting property or other property, and can apply to all properties without one standard deviation.

[0062] In the accompanying drawings, the thickness of layers, films, panels, regions, etc., is exaggerated for clarity. It should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "connected to" another element, it may be directly on or connected to another element, or an intermediate element may also exist. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there is no intermediate element. As used herein, "connection" may refer to physical and / or electrical connection. Furthermore, "electrical connection" may be the presence of other elements between two elements.

[0063] In addition, relative terms such as "lower" or "bottom" and "upper" or "top" may be used herein to describe the relationship of one element to another element, as shown in the figures. It should be understood that relative terms are intended to include different orientations of the device in addition to the orientation shown in the figures. For example, if the device in one figure is turned over, the elements described as being on the "lower" side of the other elements will be oriented on the "upper" side of the other elements. Therefore, the exemplary term "lower" can include both "lower" and "upper" orientations, depending on the particular orientation of the figure. Similarly, if the device in one figure is turned over, the elements described as being "below" or "below" other elements will be oriented as being "above" the other elements. Therefore, the exemplary terms "above" or "below" can include both above and below orientations.

[0064] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals are used in the drawings and description to refer to the same or like parts.

[0065] Figure 1 is a front view schematic diagram of an ultrasonic transducer according to a first embodiment of the present invention. Figure 2 yes Figure 1 An enlarged schematic diagram of a local area of ​​the ultrasonic transducer. Figure 3 yes Figure 2 Schematic cross-sectional view of an ultrasonic transducer. FIG. 4A to FIG. 4E yes Figure 3 Schematic cross-sectional view of the manufacturing process of an ultrasonic transducer. Figure 2 Corresponds to Figure 1 The local area Z1. Figure 3 Corresponds to Figure 2 It should be noted that in the following content, when the overlapping or non-overlapping relationship between two components is mentioned, it is defined as the two orthographic projections of the two components on the substrate 100 being overlapping or non-overlapping.

[0066] Please refer to Figure 1 and Figure 2 The ultrasonic transducer 10 includes a substrate 100 and a plurality of ultrasonic transducer units TDU. The ultrasonic transducer units TDU are disposed in an ultrasonic transceiver area RCA on the substrate 100, and each ultrasonic transducer unit TDU includes a first electrode E1, a second electrode E2 and a plurality of cavities CV.

[0067] In this embodiment, the ultrasonic transducer units TDU may be arranged in the ultrasonic transceiver area RCA of the substrate 100 along the first direction DR1 and extend in the second direction DR2. The first direction DR1 intersects (e.g., is perpendicular to) the second direction DR2. The first electrode E1 may be disposed in the ultrasonic transceiver area RCA (e.g., Figure 1 , but not limited thereto. A plurality of cavities CV are disposed in the ultrasonic transceiver area RCA and overlap the first electrode E1. More specifically, the orthographic projection of the area occupied by these cavities CV on the substrate 100 is located within the orthographic projection of the first electrode E1 on the substrate 100. That is, these cavities CV completely overlap the first electrode E1 along the normal direction of the surface of the substrate 100.

[0068] In the present embodiment, the plurality of cavities CV of the ultrasonic transducer unit TDU is, for example, a combination of a plurality of first cavities CV1 and a plurality of second cavities CV2, but is not limited thereto. The first cavities CV1 are arranged in a plurality of first cavity strings along the second direction DR2 at intervals. The second cavities CV2 are arranged in a plurality of second cavity strings along the second direction DR2 at intervals. The first cavity strings and the second cavity strings are arranged alternately along the first direction DR1 and are spaced apart from each other. That is, the plurality of first cavities CV1 and the plurality of second cavities CV2 are arranged alternately and spaced apart along the first direction DR1.

[0069] The second electrode E2 extends along the second direction DR2 on the plurality of first cavities CV1 and the plurality of second cavities CV2, and overlaps the first electrode E1, the plurality of first cavities CV1, and the plurality of second cavities CV2. More specifically, the orthographic projections of the areas occupied by the first cavities CV1 and the second cavities CV2 on the substrate 100 are located within the orthographic projections of the second electrode E2 on the substrate 100. That is, the cavities CV completely overlap the second electrode E2 along the normal direction of the surface of the substrate 100. The second electrode E2 and the first electrode E1 are electrically insulated from each other.

[0070] In the present embodiment, the second electrode E2 has a first width W1 along the first direction DR1 in the ultrasonic transceiver area RCA. A plurality of cavities CV (e.g., the first cavity CV1 and the second cavity CV2) each have a cavity width Wcv along the first direction DR1, and the first width W1 of the second electrode E2 may be greater than the cavity width Wcv. For example, the ratio of the first width W1 of the second electrode E2 to the cavity width Wcv may be greater than 6, that is, the number of cavity strings overlapped or covered by the second electrode E2 may be six, but is not limited thereto. In other embodiments not shown, the number of cavity strings covered by the second electrode may also be one, that is, the first width W1 of the second electrode may also be equal to the cavity width Wcv of the cavity CV.

[0071] On the other hand, in the present embodiment, the two edges E2e of the second electrode E2 in the first direction DR1 may be aligned with the edge CVe of the outermost cavity CV, but the present invention is not limited thereto. In the present embodiment, the second electrode E2 may have a plurality of through holes TH, and these through holes TH do not overlap with the plurality of first cavities CV1 and the plurality of second cavities CV2. The plurality of through holes TH are used to form a second cavity CV2 connected to at least one adjacent first cavity CV1, and the filler is filled into the plurality of through holes TH to form a sealing unit. For example, the through holes TH and the plurality of cavities CV of the second electrode E2 may be arranged alternately along the first direction DR1 or the second direction DR2.

[0072] First, it should be noted that, in this embodiment, the cavity CV of the ultrasonic transducer 10 is, for example, formed by using a sacrificial layer SCL (eg, Figure 4DAs shown in the figure, the distribution range of the cavity CV is defined and the cavity CV is formed by etching technology. Considering the yield of the etching process, the second electrode in the current technology must be disconnected between different cavity strings and a series-parallel structural design is adopted, resulting in a large difference between the overall width of the second electrode within the distribution range of these cavity strings and the width of the signal trace in the trace area. In addition, the width of the portion of the second electrode that overlaps the same cavity string also has periodic changes in the extension direction of the cavity string. Whether the width difference between the signal trace and the second electrode is too large, or the width of the second electrode has periodic changes in the extension direction of the cavity string, invalid interface reflection will be generated when the electrical signal is transmitted between the connected signal trace and the second electrode, resulting in energy loss.

[0073] In this embodiment, the first width W1 of the second electrode E2 in the ultrasonic transceiver area RCA remains unchanged along the second direction (i.e., the extension direction of the second electrode E2). More specifically, in addition to covering a plurality of cavities CV, the second electrode E2 also covers the area between these cavities CV, that is, a plurality of portions of the second electrode E2 that overlap a plurality of cavity strings are connected to each other. In this way, the invalid interface reflection generated when the electrical signal is transmitted in the second electrode E2 can be greatly reduced, which helps to improve the sensitivity of the ultrasonic transducer 10.

[0074] Furthermore, in the present embodiment, the substrate 100 is further provided with a wiring area WRA outside the ultrasonic transceiver area RCA, and a signal wiring WR extending from the second electrode E2 is provided in the wiring area WRA. That is, the signal wiring WR and the second electrode E2 are formed in the same film layer. It is particularly noted that the second width W2 of the signal wiring WR along the first direction DR1 is equal to the first width W1 of the second electrode E2 in the ultrasonic transceiver area RCA. Therefore, it is possible to avoid invalid interface reflection when the electrical signal passes through the connection between the second electrode E2 and the signal wiring WR, which helps to further improve the sensitivity of the ultrasonic transducer 10.

[0075] Please refer to Figure 2 and Figure 3, the ultrasonic transducer unit TDU may further include an insulating layer INS0, an insulating layer INS1 and an insulating layer INS2. The insulating layer INS1 is disposed between the first electrode E1 and the second electrode E2. The insulating layer INS0 is disposed between the insulating layer INS1 and the first electrode E1. It is particularly noted that the insulating layer INS1 has a plurality of openings OP, and these openings OP overlap with the plurality of through holes TH of the second electrode E2, respectively, wherein the plurality of openings OP form a second cavity CV2 that is connected to at least one adjacent first cavity CV1. That is, the openings OP of the insulating layer INS1 do not overlap with the plurality of cavities CV. The insulating layer INS2 is disposed on the second electrode E2, and is filled into the through holes TH of the second electrode E2 and the openings OP of the insulating layer INS1 to form a sealed unit. In the present embodiment, the insulating layer INS0, the insulating layer INS1 and the insulating layer INS2 are, for example, passivation layers, and their materials may include silicon nitride, silicon oxide, silicon carbide or aluminum oxide, but are not limited thereto.

[0076] On the other hand, the insulating layer INS1 has a spacer ISS1 separating any two adjacent first cavities CV1 or second cavities CV2 and a spacer ISS2 separating any two adjacent first cavities CV1 and second cavities CV2. The first cavity CV1 is surrounded by the adjacent spacers ISS1 and the adjacent sealing units.

[0077] The orthographic projections of the spacers ISS1 and ISS2 of the insulating layer INS1 on the substrate 100 are located within the orthographic projection of the second electrode E2 (or the first electrode E1 ) on the substrate 100 .

[0078] More specifically, the portion of the insulating layer INS1 between the plurality of cavities CV is generally distributed in a grid shape, and the orthographic projection profile of each of the cavities CV on the substrate 100 may be a rectangle, but not limited thereto. In other embodiments, the orthographic projection profile of the cavity on the substrate 100 may also be a square, rectangle, diamond, circle, hexagon or other suitable shapes.

[0079] In this embodiment, the second electrode E2, the insulating layer INS1 and the portion of the insulating layer INS2 above the cavity CV may constitute a vibrating membrane MB of the ultrasonic transducer 10. More specifically, in this embodiment, the ultrasonic transducer 10 is, for example, a capacitive micromachined ultrasonic transducer (CMUT).

[0080] For example, the first electrode E1 can be electrically coupled to a reference power source (e.g., ground). The second electrode E2 on the cavity CV can be electrically coupled to a DC power source and an AC power source, and use the output voltage of the DC power source as a reference bias. After receiving the DC bias voltage from the DC power source and the AC voltage from the AC power source, the second electrode E2 drives the vibrating film MB to vibrate to generate an ultrasonic signal.

[0081] In this embodiment, since the first electrode E1 is disposed entirely within the ultrasonic transceiver area RCA, the first electrode E1 and the second electrode E2 can also form an additional storage capacitor at the portion where they overlap outside the setting range of the plurality of cavities CV. Sufficient storage capacitors can suppress the loss of the DC charge on the second electrode E2 due to the driving of the AC signal, resulting in a level shift of the reference bias voltage. In other words, the storage capacitors added by the overlapping portions of the first electrode E1 and the second electrode E2 outside the plurality of cavities CV can also increase the operational stability of the ultrasonic transducer 10 when driven by the DC and AC coupling signals.

[0082] The following is an exemplary description of the method for manufacturing the ultrasonic transducer 10. Figure 4A First, a first electrode E1, an insulating layer INS0, and a sacrificial layer SCL are sequentially formed on a substrate 100. Based on the consideration of conductivity, the first electrode E1 is generally made of metal material, but is not limited thereto. The material of the sacrificial layer SCL includes, for example, (AL, Au, Cu, SiO2, etc.). Next, an insulating layer INS1 is formed on the sacrificial layer SCL, wherein the insulating layer INS1 covers the sacrificial layer SCL and a portion of the insulating layer INS0, such as Figure 4B shown.

[0083] Please refer to Figure 2 and Figure 4C , a second electrode E2 is formed on the insulating layer INS1, wherein the second electrode E2 has a plurality of through holes TH, and the through holes TH overlap the sacrificial layer SCL. Based on the consideration of conductivity, the second electrode E2 is generally made of metal material, but not limited thereto.

[0084] Next, a portion of the insulating layer INS1 is removed through the plurality of through holes TH of the second electrode E2 to form a plurality of openings OP, such as Figure 4D In this embodiment, the openings OP may be aligned with the plurality of through holes TH of the second electrode E2. However, the present invention is not limited thereto. In other embodiments, the plurality of through holes TH of the second electrode E2 and the plurality of openings OP of the insulating layer INS1 may be formed in the same etching process.

[0085] Please refer to Figure 4D and Figure 4EThen, the sacrificial layer SCL is removed through the through hole TH of the second electrode E2 and the opening OP of the insulating layer INS1 to form a cavity CV (eg Figure 2 The first cavity CV1 or the second cavity CV2 in the embodiment of the present invention is particularly noted that although Figure 4C Not shown, the sacrificial layer SCL has, in addition to the first portion SCLp1 for defining the cavity CV, a second portion SCLp2 extending from the first portion SCLp1 and overlapping the through hole TH of the second electrode E2. During the etching process of the sacrificial layer SCL, the second portion SCLp2 is removed first and then the first portion SCLp1 is removed. On the other hand, the aforementioned first cavity CV1 and the second cavity CV2 are formed simultaneously in the same etching process of the sacrificial layer SCL.

[0086] Therefore, after etching is completed, the through hole TH of the second electrode E2 only overlaps the chamber CHB defined by the second portion SCLp2 of the sacrificial layer SCL, but does not overlap the cavity CV defined by the first portion SCLp1 of the sacrificial layer SCL. In this embodiment, the plurality of cavities CV can be interconnected via the plurality of chambers CHB overlapping the plurality of through holes TH of the second electrode E2. From another point of view, after removing the sacrificial layer SCL, the plurality of cavities CV will reveal the plurality of interval segments (such as the plurality of interval segments) separating the plurality of cavities CV in the insulating layer INS1. Figure 2 Interval segment ISS1 and interval segment ISS2).

[0087] Please refer to Figure 4E and Figure 3 Then, an insulating layer INS2 is formed on the second electrode E2, and the insulating layer INS2 fills the through hole TH of the second electrode E2, the opening OP of the insulating layer INS1, and the part of the cavity CHB overlapping the through hole TH. At this point, the ultrasonic transducer 10 of this embodiment is manufactured.

[0088] In the present embodiment, the ultrasonic transducer 10 may further include an auxiliary electrode AE ​​disposed in the routing area WRA. The auxiliary electrode AE ​​and the first electrode E1 may be formed in the same film layer, but are electrically separated from each other. More specifically, the auxiliary electrode AE ​​located in the routing area WRA is structurally separated from the first electrode E1 located in the ultrasonic transceiver area RCA. It is particularly noted that the signal routing line WR located in the routing area WRA also overlaps with the auxiliary electrode AE, and is electrically connected to the auxiliary electrode AE ​​via the opening OP2 of the insulating layer INS0 and the insulating layer INS1. The provision of the auxiliary electrode AE ​​can improve the conductivity of the signal routing line WR in the routing area WRA, or in other words, reduce the transmission impedance of the signal routing line WR in the routing area WRA.

[0089] Some other embodiments will be listed below to explain the present invention in detail, wherein the same components will be marked with the same symbols, and the description of the same technical content will be omitted. For the omitted parts, please refer to the aforementioned embodiments and will not be repeated below.

[0090] Figure 5 is a front view schematic diagram of an ultrasonic transducer according to a second embodiment of the present invention. Figure 5 The ultrasonic transducer 10A of this embodiment is Figure 2 The difference between the ultrasonic transducers 10 is that the second electrode is configured differently. For example, in this embodiment, the second electrode E2A of the ultrasonic transducer unit TDU-A can extend from a position overlapping with a plurality of cavities CV to both sides along the first direction DR1.

[0091] That is, in this embodiment, the two edges E2e of the second electrode E2A in the first direction DR1 are not aligned with the edge CVe of the outermost cavity CV. Based on such a configuration, in addition to increasing the process margin, the storage capacitance of the ultrasonic transducer 10A can be further increased to improve the operational stability of the ultrasonic transducer 10A under the coupled signal driving of DC and AC.

[0092] Figure 6 is a front view schematic diagram of an ultrasonic transducer according to a third embodiment of the present invention. Figure 6 The ultrasonic transducer 20 of this embodiment is Figure 5 The difference between the ultrasonic transducer 10A and the ultrasonic transducer 10A is that the configuration of the signal routing in the routing area is different. For example, in this embodiment, the signal routing WR-A includes an extension portion ETP and a connection portion CP. The connection portion CP connects the extension portion ETP and the second electrode E2 in the ultrasonic transceiver area RCA.

[0093] It should be noted that the extension portion ETP of the signal trace WR-A has a second width W2" along the first direction DR1, and the second width W2" is smaller than the first width W1" of the second electrode E2 along the first direction DR1. The width Wcp of the connection portion CP of the signal trace WR-A along the first direction DR1 gradually decreases from one end connected to the second electrode E2 to the other end connected to the extension portion ETP. That is to say, in this embodiment, the connection portion between the signal trace WR-A and the second electrode E2 adopts an integrated design with a gradual line width change. Accordingly, the risk of invalid interface reflection when the electrical signal passes through the connection between the second electrode E2 and the signal trace WR-A can be reduced.

[0094] Figure 7 is a front view schematic diagram of an ultrasonic transducer according to a fourth embodiment of the present invention. Figure 8 yes Figure 7 Schematic cross-sectional view of an ultrasonic transducer. 9A to 9Cyes Figure 8 Schematic cross-sectional view of the manufacturing process of an ultrasonic transducer. Fig.10 is a schematic front view of an ultrasonic transducer according to a fifth embodiment of the present invention. Figure 8 Corresponds to Figure 7 Section line B-B'.

[0095] Please refer to Figure 7 and Figure 8 The ultrasonic transducer 30 of this embodiment is Figure 2 The difference between the ultrasonic transducer 10 and the ultrasonic transducer 10 is that the design of the second electrode is different. For example, in the ultrasonic transducer 30 of the present embodiment, the second electrode E2C of the ultrasonic transducer unit TDU-C is not provided as Figure 2 From another perspective, in this embodiment, the second electrode E2C can be filled into the plurality of openings OP of the insulating layer INS1 to form a sealing unit (eg, Figure 8 This difference comes from the difference in manufacturing methods.

[0096] The following is an exemplary description of the manufacturing method of the ultrasonic transducer 30 of this embodiment. Fig. 9A First, a first electrode E1, an insulating layer INS0 and a sacrificial layer SCL are sequentially formed on a substrate 100. Based on the consideration of conductivity, the first electrode E1 is generally made of metal material, but not limited thereto. The material of the sacrificial layer SCL includes, for example, (Al, Au, Cu, SiO2, etc.).

[0097] Next, an insulating layer INS1 is formed on the sacrificial layer SCL, wherein the insulating layer INS1 covers the sacrificial layer SCL and a portion of the insulating layer INS0. Fig. 9B It should be noted that, unlike Figure 2 The ultrasonic transducer 10 in FIG. 4B to FIG. 4D In the manufacturing process, before forming the second electrode E2C of the ultrasonic transducer 30 of this embodiment, the insulating layer INS1 has been formed with an opening OP, and the step of removing the sacrificial layer SCL is also performed before forming the second electrode E2C.

[0098] Please refer to Fig. 9B and Fig. 9C That is, the formation of the plurality of cavities CV is achieved by removing the sacrificial layer SCL through the plurality of openings OP of the insulating layer INS1. Finally, the second electrode E2C and the insulating layer INS2 are sequentially formed on the insulating layer INS1, and the second electrode E2C is filled into the plurality of openings OP of the insulating layer INS1. Figure 8 shown.

[0099] However, the present invention is not limited thereto. Fig.10In the ultrasonic transducer 30A, the manufacturing method may further include: before forming the second electrode E2D, forming an insulating layer INS1a on the insulating layer INS1, and filling the insulating layer INS1a into the opening OP of the insulating layer INS1 and a portion of the cavity CHB. Accordingly, the surface flatness of the second electrode E2D and the insulating layer INS2 formed subsequently can be improved. In the present embodiment, the material of the insulating layer INS1a and the insulating layer INS1 can be selectively the same, but is not limited thereto.

[0100] In summary, in an ultrasonic transducer of an embodiment of the present invention, a plurality of ultrasonic transducer units arranged in an ultrasonic transceiver region of a substrate at intervals along a first direction each have a first electrode, a plurality of first cavities and a second electrode arranged in an overlapping manner. These first cavities are arranged in an interval along a second direction. The second electrode extending on these first cavities has a first width along the first direction. Since the first width of the second electrode remains unchanged in the extension direction of the second electrode, the invalid interface reflection when the electrical signal is transmitted in the second electrode can be effectively suppressed, which helps to improve the sensitivity of the ultrasonic transducer.

[0101] The present invention has been described by the above-mentioned relevant embodiments, however, the above-mentioned embodiments are only examples for implementing the present invention. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, changes and modifications made without departing from the spirit and scope of the present invention are all within the scope of patent protection of the present invention.

Claims

1. An ultrasonic transducer, characterized in that: include: A base plate, provided with an ultrasonic wave transceiver area; as well as A plurality of ultrasonic transducer units are arranged on the substrate at intervals along a first direction, and each ultrasonic transducer unit comprises: A first electrode is disposed in the ultrasonic wave transceiver area; A plurality of first cavities are disposed in the ultrasonic transceiver region and overlap the first electrode, the plurality of first cavities are arranged at intervals along a second direction, and the second direction intersects the first direction; and The second electrode extends along the second direction on the multiple first cavities, overlaps the first electrode and the multiple first cavities, and is electrically insulated from the first electrode. The second electrode has a first width along the first direction in the ultrasonic transceiver area, and the first width of the second electrode remains unchanged along the second direction.

2. The ultrasonic transducer according to claim 1, characterized in that: Each of the first cavities has a cavity width along the first direction, and the first width of the second electrode is greater than or equal to the cavity width.

3. The ultrasonic transducer according to claim 1, characterized in that The second electrode also extends along the first direction over at least two first cavities.

4. The ultrasonic transducer according to claim 1, characterized in that: The second electrode has a plurality of through holes, and the plurality of through holes do not overlap the plurality of first cavities; the plurality of through holes are used to form a second cavity connected to at least one adjacent first cavity, and fillers are filled into the plurality of through holes to form a sealing unit.

5. The ultrasonic transducer according to claim 4, characterized in that: Each of the ultrasonic transducer units further comprises an insulating layer disposed between the first electrode and the second electrode. The insulating layer comprises a spacing segment separating any two adjacent ones of the plurality of first cavities. The first cavity is surrounded by adjacent spacing segments and adjacent sealing units.

6. The ultrasonic transducer according to claim 4, characterized in that: Each of the ultrasonic transducer units also includes: A first insulating layer is disposed between the first electrode and the second electrode, the first insulating layer having a plurality of openings, the plurality of openings respectively overlapping the plurality of through holes of the second electrode; and The second insulating layer is disposed on the second electrode, and the second insulating layer is also filled into the plurality of through holes of the second electrode and the plurality of openings of the first insulating layer to form the sealing unit.

7. The ultrasonic transducer according to claim 1, characterized in that: Each ultrasonic transducer unit also includes an insulating layer, which is arranged between the first electrode and the second electrode, and the insulating layer has a plurality of openings that do not overlap with the plurality of first cavities, wherein the plurality of openings are used to form a second cavity that is connected to at least one adjacent first cavity, and the second electrode is filled into the plurality of openings of the insulating layer to form a sealing unit.

8. The ultrasonic transducer according to claim 1, characterized in that: The orthographic projections of the plurality of first cavities on the substrate are located within the orthographic projection of the second electrode on the substrate.

9. The ultrasonic transducer according to claim 1, characterized in that: The substrate is also provided with a routing area outside the ultrasonic transceiver area. The routing area is provided with a signal routing extending from the second electrode. The signal routing has a second width along the first direction, and the second width is less than or equal to the first width.

10. The ultrasonic transducer according to claim 9, characterized in that: The signal routing includes: an extension portion connected to the second electrode; and The connecting portion is connected to the extending portion, and the width of the connecting portion along the first direction gradually decreases from one end connected to the second electrode to the other end connected to the extending portion.

11. A method for manufacturing an ultrasonic transducer, wherein: The ultrasonic transducer comprises a plurality of ultrasonic transducer units, each of which comprises overlapping first electrodes, a plurality of first cavities and a second electrode, the plurality of ultrasonic transducer units are arranged at intervals along a first direction, the plurality of first cavities are arranged at intervals along a second direction, and the second direction intersects the first direction, and the manufacturing method of the ultrasonic transducer comprises: forming a first electrode and a plurality of first cavities on a substrate; and A second electrode is formed on the plurality of first cavities, wherein the second electrode extends in the second direction and is electrically insulated from the first electrode, and has a first width along the first direction, and the first width of the second electrode remains unchanged along the second direction.

12. The method for manufacturing an ultrasonic transducer according to claim 11, characterized in that: The step of forming the plurality of first cavities comprises: forming a sacrificial layer on the first electrode; and The sacrificial layer is removed through the plurality of through holes of the second electrode to form the plurality of first cavities, wherein the plurality of through holes of the second electrode do not overlap the plurality of first cavities, and the through holes communicate with at least one adjacent first cavity.

13. The method for manufacturing an ultrasonic transducer according to claim 12, characterized in that: Also includes: forming a first insulating layer on the sacrificial layer; forming the second electrode on the first insulating layer; Before removing the sacrificial layer, removing a portion of the first insulating layer through the plurality of through holes of the second electrode to form a plurality of openings; as well as A second insulating layer is formed on the second electrode, and the second insulating layer is also filled into the plurality of through holes of the second electrode and the plurality of openings of the first insulating layer to form a sealing unit.

14. The method for manufacturing an ultrasonic transducer according to claim 11, characterized in that: The step of forming the plurality of first cavities comprises: forming a sacrificial layer on the first electrode; forming an insulating layer having a plurality of openings on the sacrificial layer; and removing the sacrificial layer through the plurality of openings in the insulating layer to form the plurality of first cavities; The second electrode is formed on the insulating layer, and the second electrode is also filled into the plurality of openings to form a sealing unit.

15. The method for manufacturing an ultrasonic transducer according to claim 11, characterized in that: The step of forming the plurality of first cavities comprises: forming a sacrificial layer on the first electrode; forming an insulating layer on the sacrificial layer; and The sacrificial layer is removed to form the plurality of first cavities and to expose a plurality of spacing segments separating the plurality of first cavities in the insulating layer, wherein the orthographic projections of the plurality of spacing segments on the substrate are located within the orthographic projections of the second electrode on the substrate.

16. The method for manufacturing an ultrasonic transducer according to claim 11, characterized in that: Each of the plurality of ultrasonic transducer units further includes a plurality of second cavities, and the plurality of second cavities are used to communicate with at least one adjacent first cavity. The method for manufacturing the ultrasonic transducer further includes: forming a sacrificial layer on the first electrode; forming an insulating layer on the sacrificial layer; and The sacrificial layer is removed to form the first cavities and the second cavities, and a plurality of spacers separating the first cavities and the second cavities are exposed in the insulating layer, wherein the orthographic projections of the spacers on the substrate are within the orthographic projections of the second electrode on the substrate.

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