Acoustic transduction unit, manufacturing method thereof and acoustic transducer

1. An acoustic transduction unit, comprising: a substrate, a first electrode, a vibrating film and a second electrode sequentially arranged on the substrate, and a cavity formed between the first electrode and the vibrating film, wherein

orthographic projections of the first electrode, the cavity, the vibrating film and the second electrode on the substrate are at least partially overlapped with each other at a first overlapping region, and a hollowed-out pattern is formed in the vibrating film, and

an orthographic projection of the hollowed-out pattern on the substrate and the orthographic projection of the cavity on the substrate are overlapped with each other and the hollowed-out pattern is distributed in a discontinuous manner around the first overlapping region.

2. The acoustic transduction unit of claim 1 , wherein the hollowed-out pattern comprises a central symmetric pattern, and an orthographic projection of a symmetry center of the central symmetric pattern on the substrate coincides with a center of the first overlapping region.

3. The acoustic transduction unit of claim 2 , wherein the hollowed-out pattern comprise a plurality of sub-portions, orthographic projections of which on the substrate are uniformly arranged around the center of the first overlapping region; the plurality of sub-portions comprise even number of sub-portions, two opposite sub-portions of which are symmetrically arranged by taking the center of the first overlapping region as a symmetrical center, and

the plurality of sub-portions each comprise any one of a polygon, an arc, an arc and a rectangle arranged at intervals, and a non-closed arc combined with a rectangular strip and/or a rectangular block.

4. The acoustic transduction unit of claim 1 , wherein the cavity comprises a cavity body, and an orthographic projection of the cavity body on the substrate has a shape which comprises any one of a rectangle, a circle, and a regular polygon.

5. The acoustic transduction unit of claim 4 , wherein the cavity further comprises a plurality of cavity sub-bodies, the plurality of cavity sub-bodies are arranged at intervals at a periphery of the cavity body, and the cavity sub-bodies are communicated with the cavity body; and

the orthographic projection of the hollowed-out pattern on the substrate falls into the orthographic projection of the cavity on the substrate; and the orthographic projection of the hollowed-out pattern on the substrate is not overlapped with the orthographic projection of the second electrode on the substrate.

6. The acoustic transduction unit of claim 1 , further comprising a corrosion barrier layer and a passivation layer, wherein

the corrosion barrier layer is disposed on a side of the first electrode proximal to the vibrating film, and an orthographic projection of the corrosion barrier layer on the substrate covers the orthographic projection of the first electrode on the substrate; and

the passivation layer is arranged on a side of the second electrode distal to the vibrating film, and an orthographic projection of the passivation layer on the substrate at least covers the orthographic projection of the second electrode on the substrate.

7. The acoustic transduction unit of claim 6 , wherein the orthographic projection of the passivation layer on the substrate and the orthographic projection of the hollowed-out pattern on the substrate are not overlapped with each other.

8. The acoustic transduction unit of claim 6 , wherein the orthographic projection of the passivation layer on the substrate covers the orthographic projection of the cavity on the substrate; and

at least one through hole is formed in the passivation layer, and an orthographic projection of the at least one through hole on the substrate falls into the orthographic projection of the hollowed-out pattern on the substrate.

9. The acoustic transduction unit of claim 8 , wherein the at least one through hole is filled with a hole filling material.

10. The acoustic transduction unit of claim 1 , wherein the first electrode and the second electrode are made of any one of molybdenum, aluminum, copper and gold;

the vibrating film is made of silicon nitride and/or silicon oxide;

a shape of the vibrating film comprises any one of a rectangle, a circle and a regular polygon;

a shape of the first electrode comprises any one of a rectangle, a circle and a regular polygon; and

a shape of the second electrode includes any one of a rectangle, a circle, and a regular polygon.

11. An acoustic transducer, comprising at least one acoustic transduction unit according to claim 1 .

12. A method for manufacturing an acoustic transduction unit, comprising:

forming a first electrode on a substrate; and

sequentially forming a vibrating film and a second electrode on the first electrode such that a cavity is formed between the vibrating film and the first electrode, and the orthographic projections of the first electrode, the cavity, the vibrating film and the second electrode on the substrate are at least partially overlapped with each other at a first overlapping region, a hollowed-out pattern is formed in the vibrating film, and orthographic projections of the hollowed-out pattern and the cavity on the substrate are overlapped with each other, and the hollowed-out pattern is distributed in a discontinuous manner around the first overlapping region.

13. The method of claim 12 , wherein the sequentially forming a vibrating film and a second electrode on the first electrode comprises:

forming a pattern of a corrosion barrier layer on the first electrode;

forming a pattern of a sacrificial layer on the corrosion barrier layer;

forming the vibrating film on the sacrificial layer;

forming a pattern of the second electrode on the vibrating film;

forming a pattern of a passivation layer on the second electrode; and

patterning the vibrating film such that the hollowed-out pattern is formed in the vibrating film; then removing the sacrificial layer via the hollowed-out pattern to form the cavity such that the orthographic projection of the passivation layer on the substrate is not overlapped with the orthographic projection of the hollowed-out pattern on the substrate.

14. The method of claim 12 , wherein the sequentially forming a vibrating film and a second electrode on the first electrode comprises:

forming a pattern of a corrosion barrier layer on the first electrode;

forming a pattern of a first sacrificial layer on the corrosion barrier layer;

forming a vibrating film on the first sacrificial layer, and patterning the vibrating film such that a pattern of the hollowed-out pattern is formed in the vibrating film;

forming a pattern of a second sacrificial layer in the hollowed-out pattern of the vibrating film such that the second sacrificial layer is filled in the hollowed-out pattern;

forming a pattern of the second electrode on the vibrating film;

forming a pattern of a passivation layer on the second electrode;

forming at least one through hole in the passivation layer such that an orthographic projection of the at least one through hole on the substrate falls into the orthographic projection of the hollowed-out pattern on the substrate;

removing the first sacrificial layer and the second sacrificial layer via the at least one through hole to form the cavity and the hollowed-out pattern such that an orthographic projection of the passivation layer on the substrate covers an orthographic projection of the cavity on the substrate; and

filling the at least one through hole with a hole filling material.

15. The method of claim 12 , wherein the hollowed-out pattern comprises a central symmetric pattern, and an orthographic projection of a symmetry center of the central symmetric pattern on the substrate coincides with a center of the first overlapping region.

16. The method of claim 15 , wherein the hollowed-out pattern comprises a plurality of sub-portions, orthographic projections of which on the substrate are uniformly arranged around the center of the first overlapping region; the plurality of sub-portions comprise even number of sub-portions, two opposite sub-portions of which are symmetrically arranged by taking the center of the first overlapping region as a symmetrical center, and

the plurality of sub-portions each comprise any one of a polygon, an arc, an arc and a rectangle arranged at intervals, and a non-closed arc combined with a rectangular strip and/or a rectangular block.

17. The method of claim 12 , wherein the cavity comprises a cavity body, and an orthographic projection of the cavity body on the substrate has a shape which comprises any one of a rectangle, a circle, and a regular polygon.

18. The method of claim 17 , wherein the cavity further comprises a plurality of cavity sub-bodies, the plurality of cavity sub-bodies are arranged at intervals at a periphery of the cavity body, and the cavity sub-bodies are communicated with the cavity body; and

the orthographic projection of the hollowed-out pattern on the substrate falls into the orthographic projection of the cavity on the substrate; and the orthographic projection of the hollowed-out pattern on the substrate is not overlapped with the orthographic projection of the second electrode on the substrate.

19. The method of claim 12 , wherein the first electrode and the second electrode are made of any one of molybdenum, aluminum, copper and gold;

the vibrating film is made of silicon nitride and/or silicon oxide;

a shape of the vibrating film comprises any one of a rectangle, a circle and a regular polygon;

a shape of the first electrode comprises any one of a rectangle, a circle and a regular polygon; and

a shape of the second electrode includes any one of a rectangle, a circle, and a regular polygon.