Ultrasonic oscillation sub-element and ultrasonic transduction device

Abstract

The invention provides an ultrasonic oscillator element and an ultrasonic transducer. The ultrasonic oscillator element comprises a substrate, a first lower electrode, a first insulating layer, a second insulating layer, a second lower electrode, a first upper electrode and a third insulating layer. The first lower electrode is disposed on the substrate. The first insulating layer is configured such that the first lower electrode is located between the first insulating layer and the substrate. The second insulating layer and the first insulating layer form a first cavity, wherein the first cavity is located between the first insulating layer and the second insulating layer. The first cavity includes a central region and an outer region. The second insulating layer has a first side and a second side opposite to each other. The second lower electrode is disposed adjacent to the first side of the second insulating layer and is located in the outer region of the first cavity. The first upper electrode is disposed on the second side of the second insulating layer. The third insulating layer is configured such that the second lower electrode is located between the third insulating layer and the first insulating layer.

Description

Technical Field

[0001] The present invention relates to a transducer device, and in particular to an ultrasonic oscillator element and an ultrasonic transducer device. Background Art

[0002] In the current development of ultrasonic transducers, they can be divided into bulk piezoelectric ceramic transducers (Bulk Piezoelectric Ceramic Transducers), capacitive micro-electromechanical ultrasonic transducers (Capacitive Micromachined Ultrasonic Transducers, CMUT) and piezoelectric micro-mechanical ultrasonic sensors (Piezoelectric Micromachined Ultrasonic Transducers, PMUT). However, in the future trend, since micro-mechanical ultrasonic transducers are prepared by micro-electromechanical systems (Microelectromechanical Systems, MEMS) technology, they have greater process compatibility with integrated circuits, thus becoming the best implementation solution for miniaturized ultrasonic systems. Therefore, large-scale preparation and packaging can be further realized, and applied in fields such as non-destructive testing, medical imaging, ultrasonic microscopy, fingerprint recognition or the Internet of Things. However, in the current capacitive micro-electromechanical ultrasonic transducer structure, how to increase the capacitance value to improve the transducer sensitivity is one of the goals that this field is committed to developing.

[0003] Therefore, it is necessary to design a new type of ultrasonic oscillator element and ultrasonic transducer device to overcome the above defects. Summary of the invention

[0004] The object of the present invention is to provide an ultrasonic oscillator element and an ultrasonic transducer device, which can significantly reduce the electrode spacing distance in the effective area, thereby increasing the capacitance, thereby significantly improving the working efficiency of the film.

[0005] To achieve the above-mentioned purpose, the present invention provides an ultrasonic oscillator element, comprising: a substrate; a first lower electrode, arranged on the substrate; a first insulating layer, arranged so that the first lower electrode is located between the first insulating layer and the substrate; a second insulating layer, forming a first cavity with the first insulating layer, wherein the first cavity is located between the first insulating layer and the second insulating layer, the first cavity includes a central area and an outer area, and the second insulating layer has a first side and a second side opposite to each other; a second lower electrode, arranged adjacent to the first side of the second insulating layer and located in the outer area of ​​the first cavity; a first upper electrode, arranged on the second side of the second insulating layer; and a third insulating layer, arranged so that the second lower electrode is located between the third insulating layer and the first insulating layer.

[0006] Preferably, the first cavity is located between the first lower electrode and the second lower electrode.

[0007] Preferably, the first upper electrode includes a first portion and a second portion, at least a portion of the first portion overlaps the central area of ​​the first cavity in the stacking direction, and at least a portion of the second portion overlaps the outer area of ​​the first cavity in the stacking direction.

[0008] Preferably, at least a portion of the first lower electrode overlaps the first portion of the first upper electrode in the stacking direction.

[0009] Preferably, at least a portion of the second lower electrode overlaps the second portion of the first upper electrode in the stacking direction.

[0010] Preferably, the first portion of the first upper electrode is driven by a direct current signal relative to the first lower electrode to cause the second insulating layer to be recessed toward the first cavity.

[0011] Preferably, the second portion of the first upper electrode is driven by an alternating current signal to vibrate relative to the second lower electrode.

[0012] Preferably, the second lower electrode overlaps at least a portion of the first lower electrode in the stacking direction.

[0013] Preferably, the device further comprises: a fourth insulating layer disposed in the first cavity, wherein the second lower electrode is located between the second insulating layer and the fourth insulating layer.

[0014] Preferably, it further includes: a second upper electrode, configured so that the third insulating layer is located between the second upper electrode and the first upper electrode; and a fifth insulating layer, configured so that the second upper electrode is located between the fifth insulating layer and the third insulating layer.

[0015] Preferably, the device further comprises: a second cavity disposed between the second upper electrode and the first upper electrode.

[0016] Preferably, the second cavity is disposed adjacent to any side of the third insulating layer or inside the third insulating layer.

[0017] The present invention further provides an ultrasonic transducer device, characterized in that it comprises: a plurality of ultrasonic oscillator elements as described above, arranged in an array.

[0018] Compared with the prior art, in an ultrasonic oscillator element and an ultrasonic transducer device provided by an embodiment of the present invention, the ultrasonic oscillator element includes a substrate, a first lower electrode, a first insulating layer, a second insulating layer, a second lower electrode, a first upper electrode and a third insulating layer. The second insulating layer and the first insulating layer form a first cavity, and the first cavity includes a central area and an outer area. The first lower electrode is arranged on the substrate, and the second lower electrode is adjacently arranged on the second insulating layer and is located in the outer area of ​​the first cavity, so that the first cavity is located between the first lower electrode and the second lower electrode. In this way, the electrode spacing distance in the effective area can be greatly reduced, thereby increasing the capacitance, thereby greatly improving the working efficiency of the capacitive micro-electromechanical ultrasonic transducer film. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. 4 is a schematic diagram of an ultrasonic transducer device according to an embodiment of the present invention.

[0020] Figure 2A FIG. 4 is a cross-sectional schematic diagram of an ultrasonic oscillator element according to another embodiment of the present invention.

[0021] Figure 2B for Figure 2A Schematic diagram of the oscillation of the ultrasonic oscillator element.

[0022] Figure 3A and Figure 3B They are cross-sectional schematic diagrams of ultrasonic oscillator elements according to different embodiments of the present invention.

[0023] Figure 4A FIG. 4 is a cross-sectional schematic diagram of an ultrasonic oscillator element according to another embodiment of the present invention.

[0024] Figure 4B for Figure 4A Schematic diagram of the oscillation of the ultrasonic oscillator element.

[0025] Figure 5 FIG. 4 is a cross-sectional schematic diagram of an ultrasonic oscillator element according to another embodiment of the present invention.

[0026] Figure 6 FIG. 4 is a cross-sectional schematic diagram of an ultrasonic oscillator element according to another embodiment of the present invention.

[0027] Figure 7 FIG. 4 is a cross-sectional schematic diagram of an ultrasonic oscillator element according to another embodiment of the present invention.

[0028] Figure 8 FIG. 4 is a cross-sectional schematic diagram of an ultrasonic oscillator element according to another embodiment of the present invention.

[0029] Fig. 9 FIG. 4 is a cross-sectional schematic diagram of an ultrasonic oscillator element according to another embodiment of the present invention.

[0030] Fig.10 FIG. 4 is a cross-sectional schematic diagram of an ultrasonic oscillator element according to another embodiment of the present invention.

[0031] Fig.11 FIG. 4 is a cross-sectional schematic diagram of an ultrasonic oscillator element according to another embodiment of the present invention.

[0032] Fig.12 FIG. 4 is a cross-sectional schematic diagram of an ultrasonic oscillator element according to another embodiment of the present invention.

[0033] Fig.13 FIG. 4 is a cross-sectional schematic diagram of an ultrasonic oscillator element according to another embodiment of the present invention. DETAILED DESCRIPTION

[0034] 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.

[0035] Figure 1 This is a schematic diagram of an ultrasonic transducer device according to an embodiment of the present invention. Figure 1 . This embodiment provides an ultrasonic transducer device 50, including a plurality of ultrasonic oscillator elements 100, such as capacitive micro-electromechanical ultrasonic transducers, which can be applied to non-destructive testing, medical imaging, ultrasonic microscopy, fingerprint recognition or the Internet of Things, etc., but the present invention is not limited thereto. For example, a plurality of ultrasonic oscillator elements 100 can be arranged in an array on a base 52 and arranged on the end side of a housing 54. However, the present invention does not limit the type and form of the ultrasonic transducer device 50.

[0036] Figure 2A FIG. 4 is a cross-sectional schematic diagram of an ultrasonic oscillator element according to another embodiment of the present invention. Figure 2B for Figure 2A Schematic diagram of the ultrasonic oscillator element oscillating. Please refer to Figure 2A and Figure 2B The ultrasonic oscillator element 100 shown in this embodiment can be applied to at least Figure 1The ultrasonic transducer device 50 is shown, so the following description is taken as an example. The ultrasonic oscillator element 100 includes a substrate 110, a first lower electrode 120, a first insulating layer 130, a second insulating layer 140, a second lower electrode 150, a first upper electrode 160 and a third insulating layer 170. The first lower electrode 120 is disposed on the substrate 110, and the first insulating layer 130 is disposed so that the first lower electrode 120 is located between the first insulating layer 130 and the substrate 110. The second insulating layer 140 and the first insulating layer 130 form a first cavity G1, wherein the first cavity G1 is located between the first insulating layer 130 and the second insulating layer 140. The first cavity G1 includes a central area G11 and an outer area G12. The second insulating layer 140 has a first side A1 and a second side A2 opposite to each other. The second lower electrode 150 is disposed adjacent to the first side A1 of the second insulating layer 140 and is located in the outer area G12 of the first cavity G1. Different from the conventional configuration design, in this embodiment, the first cavity G1 is located between the first lower electrode 120 and the second lower electrode 150. In this way, the electrode spacing in the effective area can be greatly reduced, thereby increasing the capacitance and greatly improving the working efficiency of the capacitive MEMS ultrasonic transducer film.

[0037] The first upper electrode 160 is disposed on the second side A2 of the second insulating layer 140. The third insulating layer 170 is disposed so that the second lower electrode 150 is located between the third insulating layer 170 and the first insulating layer 130. Specifically, in the present embodiment, the first upper electrode 160 includes a first portion 162 and a second portion 164, wherein at least a portion of the first portion 162 overlaps the central region G11 of the first cavity G1 in the stacking direction. At least a portion of the second portion 164 overlaps the outer region G12 of the first cavity G1 in the stacking direction. On the other hand, in the present embodiment, at least a portion of the first lower electrode 120 overlaps the first portion 162 of the first upper electrode 160 in the stacking direction. At least a portion of the second lower electrode 150 overlaps the second portion 164 of the first upper electrode 160 in the stacking direction. Therefore, in the present embodiment, the operation can be performed by applying a DC signal and an AC signal to different electrode portions of the ultrasonic oscillator element 100, respectively.

[0038] Specifically, when not in operation, the ultrasonic oscillator element 100 does not pass a DC signal, and its structure and appearance are as follows: Figure 2A During operation, a DC signal is first applied to the first lower electrode 120 and the first portion 162 of the first upper electrode 160, so that the first portion 162 of the first upper electrode 160 is driven by the DC signal to generate a pulling effect relative to the first lower electrode 120, so that the second insulating layer 140, the second lower electrode 150, the first upper electrode 160 and the third insulating layer 170 are recessed toward the first cavity G1, presenting a curved state, as shown in FIG. Figure 2BOn the other hand, an AC signal is applied to the second lower electrode 150 and the second portion 164 of the first upper electrode 160, so that the second portion 164 of the first upper electrode 160 is driven by the AC signal to vibrate relative to the second lower electrode 150. In other words, in this embodiment, the outer region G12 of the first cavity G1 is the main vibration working region, and the thickness of the second insulating layer 140 between the second lower electrode 150 and the first upper electrode 160 is the working spacing. In this way, the design of this embodiment can greatly reduce the electrode spacing distance in the effective area (for example, the electrode spacing distance in the effective area is reduced to half of the electrode spacing distance in the effective area of ​​the traditional structure), thereby increasing the capacitance, thereby greatly improving the working efficiency of the film.

[0039] Figure 3A and Figure 3B The following are cross-sectional diagrams of ultrasonic oscillator components according to different embodiments of the present invention. Figure 3A The ultrasonic oscillator element 100A1 shown in this embodiment is similar to Figure 2A The ultrasonic oscillator element 100 is shown. The difference between the two is that in this embodiment, the area of ​​the first lower electrode 120A in the horizontal direction can be increased so that the second lower electrode 150 overlaps at least part of the first lower electrode 120A in the stacking direction. In this way, the signal quality can be improved due to the increase in the area of ​​the ground electrode. Please refer to Figure 3B In another embodiment, the horizontal area of ​​the first bottom electrode 120A of the ultrasonic oscillator element 100A2 can be designed to be increased to exceed the range of the second bottom electrode 150 in the stacking direction, or even completely overlap with the substrate 110 in the stacking direction. In this way, when preparing the first bottom electrode 120A, the first bottom electrodes 120A of multiple ultrasonic oscillator elements 100A2 can be electrically connected to increase the process convenience and electrical performance of the first bottom electrode 120A. Figure 3B shown.

[0040] Figure 4A FIG. 4 is a cross-sectional schematic diagram of an ultrasonic oscillator element according to another embodiment of the present invention. Figure 4B for Figure 4A Schematic diagram of the ultrasonic oscillator element oscillating. Please refer to Figure 4A and Figure 4B The ultrasonic oscillator element 100B shown in this embodiment is similar to Figure 2A and Figure 2BThe ultrasonic oscillator element 100 is shown. The difference between the two is that in this embodiment, the ultrasonic oscillator element 100B further includes a fourth insulating layer 180 disposed in the first cavity G1, wherein the second bottom electrode 150 is located between the second insulating layer 140 and the fourth insulating layer 180. In this way, the difficulty of the manufacturing process can be simplified, thereby improving the manufacturing yield of the ultrasonic oscillator element 100B.

[0041] Figure 5 This is a cross-sectional diagram of an ultrasonic oscillator element according to another embodiment of the present invention. Figure 5 The ultrasonic oscillator element 100C shown in this embodiment is similar to Figure 4A The ultrasonic oscillator element 100B is shown. The difference between the two is that, in the present embodiment, the area of ​​the first lower electrode 120A in the horizontal direction can be increased so that the second lower electrode 150 overlaps at least a portion of the first lower electrode 120A in the stacking direction. In this way, the signal quality can be improved due to the increase in the area of ​​the ground electrode. In another embodiment, the area of ​​the first lower electrode 120A in the horizontal direction can be increased to exceed the range of the second lower electrode 150 in the stacking direction, and even completely overlap with the substrate 110 in the stacking direction (not shown).

[0042] Figure 6 This is a cross-sectional diagram of an ultrasonic oscillator element according to another embodiment of the present invention. Figure 6 The ultrasonic oscillator element 100D shown in this embodiment is similar to Figure 2A The ultrasonic oscillator element 100 is shown. The difference between the two is that, in this embodiment, the ultrasonic oscillator element 100D further includes a second upper electrode 190 and a fifth insulating layer 200. Specifically, the second upper electrode 190 is configured so that the third insulating layer 170 is located between the second upper electrode 190 and the first upper electrode 160. The fifth insulating layer 200 is configured so that the second upper electrode 190 is located between the fifth insulating layer 200 and the third insulating layer 170. In this way, a transducer structure with double upper electrodes can be formed, thereby improving the sensing sensitivity.

[0043] Figure 7 This is a cross-sectional diagram of an ultrasonic oscillator element according to another embodiment of the present invention. Figure 7 The ultrasonic oscillator element 100E shown in this embodiment is similar to Figure 6The ultrasonic oscillator element 100D is shown. The difference between the two is that, in the present embodiment, the area of ​​the first lower electrode 120A in the horizontal direction can be increased so that the second lower electrode 150 overlaps at least a portion of the first lower electrode 120A in the stacking direction. In this way, the signal quality can be improved due to the increase in the area of ​​the ground electrode. In another embodiment, the area of ​​the first lower electrode 120A in the horizontal direction can be increased to exceed the range of the second lower electrode 150 in the stacking direction, and even completely overlap with the substrate 110 in the stacking direction (not shown).

[0044] Figure 8 This is a cross-sectional diagram of an ultrasonic oscillator element according to another embodiment of the present invention. Figure 8 The ultrasonic oscillator element 100F shown in this embodiment is similar to Figure 6 The difference between the two is that, in this embodiment, the ultrasonic oscillator element 100F further includes a fourth insulating layer 180 disposed in the first cavity G1, wherein the second bottom electrode 150 is located between the second insulating layer 140 and the fourth insulating layer 180. In this way, the difficulty of the manufacturing process can be simplified, thereby improving the manufacturing yield of the ultrasonic oscillator element 100F.

[0045] Fig. 9 This is a cross-sectional diagram of an ultrasonic oscillator element according to another embodiment of the present invention. Fig. 9 The ultrasonic oscillator element 100G shown in this embodiment is similar to Figure 8 The ultrasonic oscillator element 100F is shown. The difference between the two is that, in the present embodiment, the area of ​​the first lower electrode 120A in the horizontal direction can be increased so that the second lower electrode 150 overlaps at least a portion of the first lower electrode 120A in the stacking direction. In this way, the quality of the signal can be improved due to the increase in the area of ​​the ground electrode. In another embodiment, the area of ​​the first lower electrode 120A in the horizontal direction can be increased to exceed the range of the second lower electrode 150 in the stacking direction, and even completely overlap with the substrate 110 in the stacking direction (not shown).

[0046] Fig.10 This is a cross-sectional diagram of an ultrasonic oscillator element according to another embodiment of the present invention. Fig.10 The ultrasonic oscillator element 100H shown in this embodiment is similar to Figure 6The ultrasonic oscillator element 100D is shown. The difference between the two is that, in this embodiment, the ultrasonic oscillator element 100H further includes a second cavity G2, which is disposed between the second upper electrode and the first upper electrode. Specifically, the second cavity G2 is disposed inside the third insulating layer 170. However, in different embodiments, the second cavity G2 can also be configured adjacent to any side of the third insulating layer 170 (not shown), and the present invention is not limited thereto. In this way, the sensing sensitivity can be further improved.

[0047] Fig.11 This is a cross-sectional diagram of an ultrasonic oscillator element according to another embodiment of the present invention. Fig.11 The ultrasonic oscillator element 100I shown in this embodiment is similar to Fig.10 The ultrasonic oscillator element 100H is shown. The difference between the two is that, in the present embodiment, the area of ​​the first lower electrode 120A in the horizontal direction can be increased so that the second lower electrode 150 overlaps at least part of the first lower electrode 120A in the stacking direction. In this way, the signal quality can be improved due to the increase in the area of ​​the ground electrode. In another embodiment, the area of ​​the first lower electrode 120A in the horizontal direction can be increased to exceed the range of the second lower electrode 150 in the stacking direction, and even completely overlap with the substrate 110 in the stacking direction (not shown).

[0048] Fig.12 This is a cross-sectional diagram of an ultrasonic oscillator element according to another embodiment of the present invention. Fig.12 The ultrasonic oscillator element 100J shown in this embodiment is similar to Fig.10 The difference between the two is that, in this embodiment, the ultrasonic oscillator element 100J further includes a fourth insulating layer 180 disposed in the first cavity G1, wherein the second bottom electrode 150 is located between the second insulating layer 140 and the fourth insulating layer 180. In this way, the difficulty of the manufacturing process can be simplified, thereby improving the manufacturing yield of the ultrasonic oscillator element 100J.

[0049] Fig.13 This is a cross-sectional diagram of an ultrasonic oscillator element according to another embodiment of the present invention. Fig.13 The ultrasonic oscillator element 100K shown in this embodiment is similar to Fig.12The ultrasonic oscillator element 100J is shown. The difference between the two is that, in the present embodiment, the area of ​​the first lower electrode 120A in the horizontal direction can be increased so that the second lower electrode 150 overlaps at least a portion of the first lower electrode 120A in the stacking direction. In this way, the signal quality can be improved due to the increase in the area of ​​the ground electrode. In another embodiment, the area of ​​the first lower electrode 120A in the horizontal direction can be increased to exceed the range of the second lower electrode 150 in the stacking direction, and even completely overlap with the substrate 110 in the stacking direction (not shown).

[0050] In summary, in the ultrasonic oscillator element and ultrasonic transducer device of the present invention, the ultrasonic oscillator element includes a substrate, a first lower electrode, a first insulating layer, a second insulating layer, a second lower electrode, a first upper electrode and a third insulating layer. The second insulating layer and the first insulating layer form a first cavity, and the first cavity includes a central area and an outer area. The first lower electrode is arranged on the substrate, and the second lower electrode is adjacently arranged on the second insulating layer and is located in the outer area of ​​the first cavity, so that the first cavity is located between the first lower electrode and the second lower electrode. In this way, the electrode spacing distance in the effective area can be greatly reduced, thereby increasing the capacitance, thereby greatly improving the working efficiency of the capacitive micro-electromechanical ultrasonic transducer film.

[0051] Although the present invention is described in conjunction with the accompanying drawings, the embodiments disclosed in the drawings are intended to exemplify the preferred embodiments of the present invention and should not be construed as limiting the present invention. In order to clearly describe the required components, the proportions in the schematic drawings do not represent the proportional relationship of the actual components.

[0052] 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 oscillator element, characterized in that: include: substrate; A first lower electrode, disposed on the substrate; a first insulating layer, configured so that the first lower electrode is located between the first insulating layer and the substrate; a second insulating layer, forming a first cavity with the first insulating layer, wherein the first cavity is located between the first insulating layer and the second insulating layer, the first cavity includes a central area and an outer area, and the second insulating layer has a first side and a second side opposite to each other; A second bottom electrode, disposed adjacent to the first side of the second insulating layer and located in the outer region of the first cavity; A first upper electrode, disposed on the second side of the second insulating layer; as well as The third insulating layer is configured so that the second lower electrode is located between the third insulating layer and the first insulating layer.

2. The ultrasonic oscillator element according to claim 1, characterized in that: The first cavity is located between the first lower electrode and the second lower electrode.

3. The ultrasonic oscillator element according to claim 1, characterized in that: The first upper electrode includes a first portion and a second portion, at least a portion of the first portion overlaps the central region of the first cavity in a stacking direction, and at least a portion of the second portion overlaps the outer region of the first cavity in the stacking direction.

4. The ultrasonic oscillator element according to claim 3, characterized in that: At least a portion of the first lower electrode overlaps the first portion of the first upper electrode in the stacking direction.

5. The ultrasonic oscillator element according to claim 3, characterized in that: At least a portion of the second lower electrode overlaps the second portion of the first upper electrode in the stacking direction.

6. The ultrasonic oscillator element according to claim 3, characterized in that: The first portion of the first upper electrode is driven by a direct current signal relative to the first lower electrode to cause the second insulating layer to be recessed toward the first cavity.

7. The ultrasonic oscillator element according to claim 3, characterized in that: The second portion of the first upper electrode is driven by an AC signal to vibrate relative to the second lower electrode.

8. The ultrasonic oscillator element according to claim 1, characterized in that: The second lower electrode overlaps at least a portion of the first lower electrode in a stacking direction.

9. The ultrasonic oscillator element according to claim 1, characterized in that: Also includes: The fourth insulating layer is disposed in the first cavity, wherein the second lower electrode is located between the second insulating layer and the fourth insulating layer.

10. The ultrasonic oscillator element according to claim 1, characterized in that: Also includes: a second upper electrode, configured so that the third insulating layer is located between the second upper electrode and the first upper electrode; as well as The fifth insulating layer is configured so that the second upper electrode is located between the fifth insulating layer and the third insulating layer.

11. The ultrasonic oscillator element according to claim 10, characterized in that: Also includes: The second cavity is disposed between the second upper electrode and the first upper electrode.

12. The ultrasonic oscillator element according to claim 11, characterized in that: The second cavity is adjacently disposed on any side of the third insulating layer or inside the third insulating layer.

13. An ultrasonic transducer device, characterized in that: include: A plurality of ultrasonic oscillator elements as claimed in any one of claims 1 to 12 are arranged in an array.

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