CN115638809A - Suspension type piezoelectric ultrasonic sensor and manufacturing method thereof - Google Patents
Suspension type piezoelectric ultrasonic sensor and manufacturing method thereof Download PDFInfo
- Publication number
- CN115638809A CN115638809A CN202110819590.0A CN202110819590A CN115638809A CN 115638809 A CN115638809 A CN 115638809A CN 202110819590 A CN202110819590 A CN 202110819590A CN 115638809 A CN115638809 A CN 115638809A
- Authority
- CN
- China
- Prior art keywords
- semiconductor substrate
- ultrasonic sensor
- piezoelectric ultrasonic
- cavity
- columnar
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Landscapes
- Pressure Sensors (AREA)
Abstract
The application provides a suspension piezoelectric ultrasonic sensor and a manufacturing method thereof, wherein the suspension piezoelectric ultrasonic sensor comprises a semiconductor substrate and a piezoelectric ultrasonic sensing element; the semiconductor substrate comprises a columnar setting area, a peripheral wall and at least one bridging part, wherein a cavity is formed between the columnar setting area and the peripheral wall, the cavity surrounds the columnar setting area, and the bridging part is connected with the columnar setting area and the peripheral wall; the piezoelectric ultrasonic sensing element is arranged on the columnar arrangement area. By arranging the cavity and the bridging part on the semiconductor substrate, the required frequency can be adjusted in the mode, so that the required sound pressure and emission angle are adjusted, and a larger process margin is provided.
Description
Technical Field
The present disclosure relates to the field of sensing technologies, and more particularly, to a suspension type piezoelectric ultrasonic sensor and a method for manufacturing the same.
Background
In recent years, ultrasonic sensors have been widely applied to various products such as fingerprint recognition, sweeping robots, etc., and the application range is becoming wider. With the miniaturization of some products, the products are usually manufactured by matching with semiconductor wafer level processes. Generally, the conventional ultrasonic sensor is usually used to clearly distinguish the incident wave and the reflected wave by a vacuum chamber, so as to achieve the effect of clear identification.
However, in the prior art, the vacuum chamber of the ultrasonic sensor is sealed inside the ultrasonic sensor, and after the ultrasonic sensor is manufactured, the volume of the chamber is fixed, and the resonant frequency of the corresponding transmitted wave is also fixed. However, the resonant frequency of the ultrasonic sensor may not reach the required emission angle and sound pressure, and the design needs to be redesigned. In addition to the relatively high cost, the size and space of the cavity required for ultrasonic sensors are also reduced, and the overall design is limited by the process margin.
Disclosure of Invention
To solve the problems encountered in the prior art, a suspension-type piezoelectric ultrasonic sensor and a method for fabricating the same are provided. Wherein the suspension type piezoelectric ultrasonic sensor comprises a semiconductor substrate and a piezoelectric ultrasonic sensing element; the semiconductor substrate comprises a columnar setting area, a peripheral wall and at least one bridging part, wherein a cavity is formed between the columnar setting area and the peripheral wall, the cavity surrounds the columnar setting area, and the bridging part is connected with the columnar setting area and the peripheral wall; the piezoelectric ultrasonic sensing element is arranged on the columnar arrangement area.
In some embodiments, the semiconductor substrate further comprises at least one via, the via penetrating the semiconductor substrate and communicating with the cavity.
In more detail, in some embodiments, the via is adjacent to the pillar-shaped disposition region.
In more detail, in some embodiments, the semiconductor substrate includes a plurality of through holes penetrating through the semiconductor substrate and distributed around the pillar-shaped arrangement region, and the through holes are communicated with the cavity.
In some embodiments, the semiconductor substrate includes a plurality of bridge portions, each of which is respectively connected to the pillar-shaped setting region and the peripheral wall.
In more detail, in some embodiments, the bridging portions are symmetrically located around the cylindrically-shaped setting region.
In some embodiments, the width of the piezoelectric ultrasonic sensor is smaller than that of the pillar-shaped disposing region.
In some embodiments, the thickness of the semiconductor substrate is 200 μm to 700 μm.
In some embodiments, the length of the bridge is less than 1000 μm.
The method comprises the steps of defining, arranging the elements, perforating and forming the cavity; the defining step is to provide a semiconductor substrate, and a columnar setting area is defined on the semiconductor substrate; the element setting step is to form a piezoelectric ultrasonic sensing element in the columnar setting area; the through hole step is to form a through hole on the semiconductor substrate, and the through hole penetrates through the semiconductor substrate; the cavity forming step is to remove the area adjacent to the columnar setting area on the semiconductor substrate along the through hole, so that the semiconductor substrate forms a cavity around the columnar setting area, the periphery of the cavity is a peripheral wall, the cavity is communicated with the through hole, and the columnar setting area is connected with the peripheral wall through at least one bridging part.
In some embodiments, a substrate thinning step is further included before the through-hole step, and the substrate thinning step reduces the thickness of the semiconductor substrate. In more detail, in some embodiments, the thickness of the semiconductor substrate is 200 μm to 700 μm.
In some embodiments, the via step forms a plurality of vias, the vias penetrating through the semiconductor substrate and being distributed around the pillar-shaped arrangement region, and the vias communicating with the cavity.
In some embodiments, the cavity forming step makes the semiconductor substrate include a plurality of bridge portions, each bridge portion being respectively connected to the columnar arrangement region and the peripheral wall.
In more detail, in some embodiments, the bridging portions are symmetrically located around the cylindrically-shaped setting region.
In some embodiments, the width of the piezoelectric ultrasonic sensor is smaller than the pillar-shaped setting area.
In some embodiments, the length of the bridge is less than 1000 μm.
As described in the foregoing embodiments, after the piezoelectric ultrasonic sensor is completed, a cavity is further formed on the semiconductor substrate, and the remaining bridge portion is used to connect the pillar-shaped mounting region where the piezoelectric ultrasonic sensor is mounted and the peripheral wall, so that the required resonant frequency, and thus the required sound pressure and emission angle can be adjusted, thereby providing a larger process margin.
Drawings
FIG. 1 is a top view of a first embodiment of a floating piezoelectric ultrasonic sensor.
Fig. 2 isbase:Sub>A cross-sectional view taken along linebase:Sub>A-base:Sub>A of fig. 1.
FIG. 3 is a top view of a second embodiment of a suspended piezoelectric ultrasonic sensor.
FIG. 4 is a top view of a third embodiment of a suspended piezoelectric ultrasonic sensor.
FIG. 5 is a flow chart of a method for fabricating a suspension piezoelectric ultrasonic sensor.
Description of the reference numerals:
1: a suspended piezoelectric ultrasonic sensor;
10: a semiconductor substrate;
11: a columnar setting area;
13: a peripheral wall;
15: a bridge portion;
17: a cavity;
19: through holes are formed;
20: a piezoelectric ultrasonic sensor;
s1: a method for manufacturing a suspension type piezoelectric ultrasonic sensor;
s10: a defining step;
s20: an element setting step;
s25: thinning the substrate;
s30: a through hole step;
s40: and a cavity forming step.
Detailed Description
It will be understood that when an element is referred to as being "connected" or "disposed" to another element, it can be directly on the other element or intervening elements may also be present, through which the element is connected to the other element. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, it is understood that there are no intervening elements explicitly defined herein.
In addition, the terms "first", "second", "third" and the like are only used for distinguishing one element, component, region or section from another element, component, region, layer or section, and do not necessarily indicate a sequential order. Furthermore, relative terms, such as "lower" and "upper," may be used herein to describe one element's relationship to another element, and it is to be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures. For example, if the device in one of the figures is turned over, elements described as being on the "lower" side of other elements would then be oriented on "upper" sides of the other elements. This represents only a relative orientation relationship, not an absolute orientation relationship.
FIG. 1 is a top view of a first embodiment of a suspended piezoelectric ultrasonic sensor. Fig. 2 isbase:Sub>A sectional view taken along linebase:Sub>A-base:Sub>A of fig. 1. As shown in fig. 1 and 2, the floated piezoelectric ultrasonic sensor 1 of the first embodiment includes a semiconductor substrate 10 and a piezoelectric ultrasonic sensor 20. The semiconductor substrate 10 includes a column-shaped region 11, a peripheral wall 13, and a bridge portion 15, wherein a cavity 17 is formed between the column-shaped region 11 and the peripheral wall 13, the cavity 17 surrounds the column-shaped region 11, and the bridge portion 15 connects the column-shaped region 11 and the peripheral wall 13. The piezoelectric ultrasonic sensor 20 is disposed on the pillar-shaped mounting region 11.
More specifically, the cavity 17 between the pillar-shaped region 11 and the peripheral wall 13 may be formed by removing a portion of the semiconductor substrate 10 by laser or etching, such that the pillar-shaped region 11 is in an island shape in the cavity 17, and the piezoelectric ultrasonic sensor 20 is suspended. In more detail, the width of the piezoelectric ultrasonic sensor 20 is smaller than that of the pillar-shaped setting region 11. In the first embodiment, there is only one bridging portion 15 connecting the columnar arrangement region 11 and the peripheral wall 13. Thus, even if the cavity is formed in the piezoelectric ultrasonic sensor 20, the length of the bridge 15 can be adjusted to adjust the desired resonant frequency. In general, the length of the bridge 15 is less than 1000 μm, preferably 300 to 750 μm. As the length of the bridge 15 decreases, the resonant frequency and thus the emission angle can be increased. Thus, a wider process margin is provided. Furthermore, the component which is also the resonant frequency and is judged to be a defective product can meet the requirement through secondary processing, thereby providing a scheme of fine adjustment and correction.
Referring again to fig. 2, the semiconductor substrate 10 further includes at least one via 19, the via 19 penetrating through the semiconductor substrate 10 and communicating with the cavity 17. More specifically, the via 19 may be accomplished by laser drilling techniques, adjacent to the pillar-shaped region 11, to provide a path for subsequently removing a portion of the semiconductor substrate 10, forming the cavity 17.
In more detail, in some embodiments, the number of the through holes 19 may be multiple, and the multiple through holes 19 are distributed around the pillar-shaped setting region 11.
In order to achieve a fast via 19 and reduce thermal damage of laser processing, the semiconductor substrate 10 may be further thinned before the via 19, generally by etching, which is less costly and more efficient. In addition, the thickness of the semiconductor substrate 10 directly affects the sound pressure. The thickness of the semiconductor substrate 10 is reduced and the sound pressure is thus increased, so that the desired effect can also be adjusted by controlling the thinning of the semiconductor substrate 10 in addition to providing assistance in forming the through hole 19. Here, the thickness of the semiconductor substrate 10 is 200 μm to 700 μm, preferably 300 μm to 600 μm.
FIG. 3 is a top view of a second embodiment of a suspended piezoelectric ultrasonic sensor. Figure 4 is a top view of a third embodiment of a suspended piezoelectric ultrasonic sensor. As shown in fig. 3 and 4, referring to fig. 1 and 2, the suspension-type piezoelectric ultrasonic sensor 1 of the second and third embodiments is different from the first embodiment in the number of the bridge portions 15. The second embodiment has two bridge portions 15, and the third embodiment has four bridge portions 15. The bridging portions 15 are connected to the columnar setting region 11 and the peripheral wall 13, respectively.
More specifically, in the third embodiment, the bridging portions 15 are symmetrically located around the columnar arrangement region 11. Here, the number, position and arrangement of the bridging portions 15 can be adjusted according to actual requirements. More specifically, the total length of all the bridge portions 15 is inversely proportional to the resonant frequency and the emission angle. The required resonance frequency and the emission angle can also be adjusted by adjusting the number and the total length of the bridge parts 15.
FIG. 5 is a flow chart of a method for fabricating a suspension piezoelectric ultrasonic sensor. As shown in fig. 5 and referring to fig. 1 to 4, the method S1 for manufacturing a suspension-type piezoelectric ultrasonic sensor includes a defining step S10, a component disposing step S20, a hole passing step S30, and a cavity forming step S40. The defining step S10 is to provide a semiconductor substrate 10, and a column-shaped setting region 11 is defined on the semiconductor substrate 10. The device mounting step S20 is to form the piezoelectric ultrasonic sensor device 20 on the pillar-shaped mounting region 11.
The via step S30 is to form a via 19 on the semiconductor substrate 10, and the via 19 penetrates the semiconductor substrate 10. The cavity forming step S40 is to remove a region of the semiconductor substrate 10 adjacent to the pillar-shaped setting region 11 along the through hole 19, so that the semiconductor substrate 10 forms a cavity 17 around the pillar-shaped setting region 11, the periphery of the cavity 17 is a peripheral wall 13, the cavity 17 is communicated with the through hole 19, and the pillar-shaped setting region 11 is connected with the peripheral wall 13 by at least one bridge portion 15 formed by remaining and not removing the bridge portion. Here, the cavity forming step S40 may be performed by removing the semiconductor material by laser or etching.
Referring again to fig. 5, further, a substrate thinning step S25 is further included before the through hole step S30, the substrate thinning step S25 reduces the thickness of the semiconductor substrate 10, and the required effect can be adjusted by controlling to thin the semiconductor substrate 10 besides providing assistance for forming the through hole 19.
In summary, after the piezoelectric ultrasonic sensor 20 is completed, the cavity 17 is further formed on the semiconductor substrate 10, and the remaining bridge portion 15 connects the pillar-shaped mounting region 11 where the piezoelectric ultrasonic sensor 20 is mounted and the peripheral wall 13, so that the required resonant frequency, and thus the required sound pressure and emission angle can be adjusted, thereby providing a larger process margin.
Although the present disclosure has been described with reference to the preferred embodiments, it should be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the disclosure. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (17)
1. A suspended piezoelectric ultrasonic sensor, comprising:
the semiconductor substrate comprises a columnar setting area, a peripheral wall and at least one bridging part, wherein a cavity is formed between the columnar setting area and the peripheral wall, the cavity surrounds the columnar setting area, and the bridging part is connected with the columnar setting area and the peripheral wall; and
the piezoelectric ultrasonic sensing element is arranged on the columnar arrangement area.
2. The floated piezoelectric ultrasonic sensor as claimed in claim 1, wherein the semiconductor substrate further comprises at least one through hole penetrating the semiconductor substrate and communicating with the cavity.
3. The suspended piezoelectric ultrasonic sensor of claim 2, wherein the through hole is adjacent to the pillar-shaped mounting region.
4. The suspended piezoelectric ultrasonic sensor according to claim 2, wherein the semiconductor substrate comprises a plurality of through holes, the plurality of through holes penetrating the semiconductor substrate and being distributed around the pillar-shaped region, and the plurality of through holes being communicated with the cavity.
5. The suspended piezoelectric ultrasonic sensor according to claim 1, wherein the semiconductor substrate includes a plurality of bridging portions, and each bridging portion is connected to the pillar-shaped installation region and the peripheral wall.
6. The ultrasonic transducer of claim 5, wherein the plurality of bridging portions are symmetrically located around the cylindrical region.
7. The suspended piezoelectric ultrasonic sensor according to claim 1, wherein the width of the piezoelectric ultrasonic sensor element is smaller than the pillar-shaped installation region.
8. The suspended piezoelectric ultrasonic sensor according to claim 1, wherein the thickness of the semiconductor substrate is 200 μm to 700 μm.
9. The suspended piezoelectric ultrasonic sensor of claim 1, wherein the bridge portion has a length of less than 1000 μm.
10. A method for manufacturing a suspension-type piezoelectric ultrasonic sensor, comprising:
a defining step, providing a semiconductor substrate, wherein a columnar setting area is defined on the semiconductor substrate;
an element mounting step of forming a piezoelectric ultrasonic sensor in the columnar mounting region;
a through hole step of forming a through hole on the semiconductor substrate, wherein the through hole penetrates through the semiconductor substrate; and
and a cavity forming step, namely removing an area adjacent to the columnar setting area on the semiconductor substrate along the through hole, so that the semiconductor substrate forms a cavity around the columnar setting area, the periphery of the cavity is a peripheral wall, the cavity is communicated with the through hole, and the columnar setting area is connected with the peripheral wall through at least one bridging part.
11. The method of claim 10, further comprising a step of thinning the substrate before the step of perforating, wherein the step of thinning the substrate reduces the thickness of the semiconductor substrate.
12. The method as claimed in claim 10 or claim 11, wherein the thickness of the semiconductor substrate is 200 μm to 700 μm.
13. The method of claim 10, wherein the via-drilling step forms a plurality of vias, the plurality of vias penetrate through the semiconductor substrate and are distributed around the pillar-shaped region, and the plurality of vias are connected to the cavity.
14. The method of claim 10, wherein the cavity forming step includes a plurality of bridging portions on the semiconductor substrate, and each bridging portion is connected to the pillar-shaped region and the peripheral wall of the cavity.
15. The method of claim 14, wherein the bridging portions are symmetrically located around the cylindrical region.
16. The method of claim 10, wherein the width of the piezoelectric ultrasonic sensor element is smaller than the pillar-shaped installation area.
17. The method of claim 10, wherein the bridge portion has a length less than 1000 μm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110819590.0A CN115638809A (en) | 2021-07-20 | 2021-07-20 | Suspension type piezoelectric ultrasonic sensor and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110819590.0A CN115638809A (en) | 2021-07-20 | 2021-07-20 | Suspension type piezoelectric ultrasonic sensor and manufacturing method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115638809A true CN115638809A (en) | 2023-01-24 |
Family
ID=84940207
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110819590.0A Pending CN115638809A (en) | 2021-07-20 | 2021-07-20 | Suspension type piezoelectric ultrasonic sensor and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115638809A (en) |
-
2021
- 2021-07-20 CN CN202110819590.0A patent/CN115638809A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP1738147B1 (en) | Method for producing a quartz sensor | |
| US7772026B2 (en) | MEMS device package and method for manufacturing the same | |
| US9180489B2 (en) | Electromechanical transducer | |
| US10616687B2 (en) | Microphone and manufacturing method thereof | |
| US20070222006A1 (en) | Micromechanical component and corresponding manufacturing method | |
| EP3249371B1 (en) | Differential pressure sensor full overpressure protection device | |
| US8146437B2 (en) | Diaphragm structure and MEMS device | |
| KR20070084391A (en) | Silicon microphone | |
| KR20050076717A (en) | Capacitive sensor for dynamical quantity | |
| KR102313151B1 (en) | Method for Fabricating Stress Decoupled Micromechanical Pressure Sensors | |
| US9963340B2 (en) | Pressure sensor die over pressure protection for high over pressure to operating span ratios | |
| US6802222B2 (en) | Diaphragm-type semiconductor device and method for manufacturing diaphragm-type semiconductor device | |
| CN115638809A (en) | Suspension type piezoelectric ultrasonic sensor and manufacturing method thereof | |
| CN215217631U (en) | Suspension type piezoelectric ultrasonic sensor | |
| TWI708511B (en) | Piezoresistive microphone and method of fabricating the same | |
| TWI809455B (en) | Suspended piezoelectric ultrasonic transducers and the manufacturing method thereof | |
| TWM618737U (en) | Suspending piezoelectric ultrasonic sensor | |
| EP3682210B1 (en) | Capacitive pressure sensors and other devices having a suspended membrane and having rounded corners at an anchor edge | |
| US20070126072A1 (en) | Surface acoustic wave pressure sensors | |
| US20210199524A1 (en) | Sensor membrane structure and method for forming the same | |
| KR101893486B1 (en) | Rigid Backplate Structure Microphone and Method of Manufacturing the Same | |
| WO2010008344A2 (en) | Extended sensor back volume | |
| TW202213824A (en) | Piezoelectric micromachined ultrasonic transducer and method of fabricating the same | |
| US20230146234A1 (en) | Fabrication Method of MEMS Transducer Element | |
| US11323823B1 (en) | MEMS device with a diaphragm having a slotted layer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |