CN115752521A - Waterproof sensor and electronic equipment - Google Patents
Waterproof sensor and electronic equipment Download PDFInfo
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- CN115752521A CN115752521A CN202211186654.9A CN202211186654A CN115752521A CN 115752521 A CN115752521 A CN 115752521A CN 202211186654 A CN202211186654 A CN 202211186654A CN 115752521 A CN115752521 A CN 115752521A
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- vibrating diaphragm
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Abstract
The invention provides a waterproof sensor and electronic equipment, wherein the waterproof sensor comprises a structure formed by assembling an MEMS chip and an IC chip, wherein the MEMS chip comprises a main body structure and an upper cover layer fixed with the main body structure, and a passivation layer is arranged on the surface of a vibrating diaphragm of the main body structure; the upper cover layer comprises a cavity communicated with the outside, the upper cover layer is covered on the passivation layer, and the passivation layer is used for isolating the vibrating diaphragm from contacting with the outside. The invention can solve the problems that the product size is difficult to be reduced due to process limitation, the performance of a chip is reduced and the like caused by the complex packaging process of the existing waterproof sensor.
Description
Technical Field
The invention relates to the technical field of electroacoustic conversion, in particular to a waterproof sensor and electronic equipment.
Background
At present, there are two waterproof methods for MEMS (Micro electro mechanical Systems ) sensors: waterproof membrane MEMS sensor or casting glue MEMS sensor. The waterproof film has high requirements on the size and the structure of a device, and needs to meet the bonding requirement of the waterproof film, and the waterproof film is mostly used for waterproofing the whole machine); the defoaming difficulty of the pouring sealant is high during packaging, and the requirement on the performance of the glue is high.
The two packaging modes have complex packaging process, the product size is limited by the packaging process and is difficult to be reduced, and the performance of the chip can be reduced due to the mismatching of the thermal expansion coefficients and other performances of different packaging materials and the chip, so that the invention provides a novel waterproof sensor for solving the problems.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide a waterproof sensor and an electronic device, so as to solve the problems that the size of the product is difficult to be reduced due to process limitations and the performance of the chip is reduced due to the complicated packaging process of the conventional waterproof sensor.
The invention provides a waterproof sensor, which comprises a structure formed by assembling an MEMS chip and an IC chip, wherein the MEMS chip comprises a main body structure and an upper cover layer fixed with the main body structure, the main body structure comprises a vibrating diaphragm, and a passivation layer is arranged on the surface of the vibrating diaphragm;
the upper cover layer comprises a cavity communicated with the outside, the upper cover layer is covered on the passivation layer, and the passivation layer is used for isolating the vibrating diaphragm from contacting with the outside.
Preferably, the main structure further comprises a back electrode, wherein,
a cavity is arranged between the back electrode and the vibrating diaphragm, the cavity and the back electrode form a capacitor. In addition, the preferable scheme is that a through hole is arranged on the upper cover layer and is used for communicating the outside with the cavity;
the through hole transmits the external pressure to the vibrating diaphragm through the cavity, so that the vibrating diaphragm vibrates to cause the change of the capacitance.
In addition, it is preferable that the body structure further includes a silicon substrate, wherein,
a cavity is arranged between the silicon substrate and the vibrating diaphragm, and a resistor is arranged on the vibrating diaphragm, wherein the silicon substrate, the cavity, the vibrating diaphragm and the resistor form a Wheatstone resistor bridge.
In addition, the passivation layer is preferably disposed on the diaphragm by deposition, wherein the passivation layer is made of an insulating material and has a thickness of 3-10 μm.
In addition, it is preferable that a groove is provided in the upper cover layer, the groove being used for accommodating a sealing ring or a sealant, wherein,
the MEMS chip is assembled with the electronic equipment through the groove and the sealing ring or the sealant.
In addition, the preferable scheme is that corresponding internal connection bonding pads are respectively arranged on the MEMS chip and the IC chip, and the MEMS chip and the IC chip are welded and fixed through the internal connection bonding pads; alternatively, the first and second electrodes may be,
the MEMS chip and the IC chip are fixed with each other in a bonding mode.
In addition, preferably, an external bonding pad is further disposed on the IC chip, and the IC chip is soldered to the electronic device through the external bonding pad.
In addition, it is preferable that the capacitor layer and the upper cover layer are fixed to each other by bonding.
The invention also provides electronic equipment, which comprises the waterproof sensor.
According to the technical scheme, the passivation layer is arranged on the surface of the vibrating diaphragm and used for isolating the vibrating diaphragm from contacting with the outside, so that the MEMS has the functions of water resistance and liquid resistance, and the problem that the traditional waterproof sensor filled with the sealing glue and the waterproof film is difficult to assemble is solved.
To the accomplishment of the foregoing and related ends, one or more aspects of the invention comprise the features hereinafter fully described. The following description and the annexed drawings set forth in detail certain illustrative aspects of the invention. These aspects are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Further, the present invention is intended to include all such aspects and their equivalents.
Drawings
Other objects and results of the present invention will become more apparent and more readily appreciated as the same becomes better understood by reference to the following description and appended claims, taken in conjunction with the accompanying drawings. In the drawings:
FIG. 1 is a schematic diagram of a waterproof sensor structure according to an embodiment of the invention;
FIG. 2 is a schematic top view of a waterproof sensor according to an embodiment of the invention;
FIG. 3 is a schematic diagram of a back pole structure of a MEMS chip according to an embodiment of the invention;
FIG. 4 is a schematic diagram of a capacitor structure of a MEMS chip according to an embodiment of the invention;
FIG. 5 is a schematic diagram of a top cap structure of a MEMS chip according to an embodiment of the invention;
FIG. 6 is a schematic diagram of a MEMS chip according to an embodiment of the present invention;
fig. 7 is a schematic view of an assembly structure of a waterproof sensor and an electronic device according to an embodiment of the invention.
Wherein the reference numerals include: 1. MEMS chip, 2, IC chip, 10, through-hole, 11, recess, 12, cavity, 13, passivation layer, 14, vibrating diaphragm, 15, cavity, 16, back pole, 17, first internal connection pad, 21, second internal connection pad, 22, external connection pad, 3, electronic equipment, 4, sealing washer.
The same reference numbers in all figures indicate similar or corresponding features or functions.
Detailed Description
In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more embodiments. It may be evident, however, that such embodiment(s) may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing one or more embodiments.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.
Aiming at the problems that the size of a product is difficult to be reduced due to process limitation, the performance of a chip is reduced and the like caused by the complex packaging process of the existing waterproof sensor, the invention provides a waterproof sensor and electronic equipment.
Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
In order to illustrate the structure of the waterproof sensor provided by the present invention, fig. 1 to 6 are exemplarily illustrated from different angles, respectively. Specifically, fig. 1 shows a waterproof sensor structure according to an embodiment of the present invention; FIG. 2 illustrates a waterproof sensor top view configuration according to an embodiment of the present invention; FIG. 3 illustrates a back pole structure of a MEMS chip in accordance with an embodiment of the present invention; FIG. 4 illustrates a capacitive structure of a MEMS chip according to an embodiment of the present invention; FIG. 5 illustrates a cap-up structure of a MEMS chip according to an embodiment of the invention; FIG. 6 illustrates a MEMS chip structure in accordance with an embodiment of the present invention.
As shown in fig. 1 to 6, the present invention provides a waterproof sensor, which includes a structure formed by assembling a MEMS chip 1 and an IC chip 2, wherein the MEMS chip 1 includes a main body structure and an upper cover layer fixed to the main body structure, the main body structure includes a diaphragm 14, and a passivation layer 13 is disposed on a surface of the diaphragm 14; the upper cover layer comprises a cavity 12 communicated with the outside, and the upper cover layer is covered on a passivation layer 13, and the passivation layer 13 is used for isolating the diaphragm 14 from contacting with the outside.
In the embodiment of the present invention, the passivation layer 13 is deposited on the diaphragm 14, and generally, an insulating material such as silicon nitride, silicon oxide, etc. is used, wherein the thickness of the passivation layer is 3-10 micrometers, and in a specific application, an appropriate thickness may be selected according to a waterproof requirement, and is not limited to the above specification.
In an embodiment of the present invention, the main body structure and the upper cover layer are fixed to each other by bonding. The MEMS chip 1 is used for measuring air pressure or liquid pressure, and converts a pressure signal into an electrical signal. The IC chip 2 is used for a processing circuit of the MEMS signal, and adopts an IC process mature in the industry, which is not described herein in detail.
In the embodiment of the present invention, the main body structure may adopt a capacitive mode or a wheatstone resistance bridge mode. When the main structure adopts a capacitance mode, the main structure further comprises a back electrode 16, wherein a cavity 15 is arranged between the back electrode 16 and the diaphragm 14, the cavity 15 and the back electrode 16 form a capacitor. Wherein, a through hole 10 is arranged on the upper cover layer, and the through hole 10 is used for communicating the outside with a cavity 12; the through hole 10 transmits the external pressure to the diaphragm 14 through the cavity 12, so that the diaphragm 14 vibrates to cause the change of capacitance.
That is, the cavity 12 is directly in contact with the external environment, and the passivation layer 13 is insulated from the external environment; when the external environment changes, the vibrating diaphragm 14 deforms, the vibrating diaphragm 14, the back electrode 16 and the cavity 15 form a capacitor, the change of the vibrating diaphragm 14 causes the change of the capacitor, and a changed electric signal is transmitted to the IC chip; the conversion of the pressure signal to the electric signal is realized.
When the main structure adopts a Wheatstone resistance bridge mode, namely: the main body structure further comprises a silicon substrate, wherein a cavity is arranged between the silicon substrate and the vibrating diaphragm, and a resistor is arranged on the vibrating diaphragm, wherein the silicon substrate, the cavity, the vibrating diaphragm and the resistor form a Wheatstone resistor bridge. That is, a resistor may be formed on the diaphragm 14, and a wheatstone resistor bridge manner is adopted; the deformation of the diaphragm 14 causes a change in resistance and may also convert the pressure signal into an electrical signal.
In the embodiment of the present invention, a groove 11 is formed in the upper cover layer, and the groove 11 is used for accommodating the sealing ring 4 or the sealant, wherein the MEMS chip 1 is assembled with the sealing ring 4 or the sealant and the electronic device through the groove 11.
Wherein, the groove 11 is used for matching with a whole machine waterproof structure. The groove 11 can be matched with a sealing ring to realize water resistance, and can also be bonded with a complete machine by using waterproof glue to realize water resistance. The shape and the size of the groove can be designed according to the whole waterproof structure.
In the embodiment of the invention, the MEMS chip 1 and the IC chip 2 are respectively provided with corresponding internal connection pads, and the MEMS chip 1 and the IC chip 2 are welded and fixed through the internal connection pads. Wherein, a first internal connection pad 17 is arranged on the MEMS chip 1, a second internal connection pad 21 is arranged on the IC chip 2, and the MEMS chip 1 and the IC chip 2 are welded and fixed through the first internal connection pad 17 and the second internal connection pad.
In addition, in the implementation of the present invention, the MEMS chip 1 and the IC chip 2 may be fixed to each other by bonding, that is: the MEMS chip 1 and the IC chip 2 are respectively provided with corresponding bonding pads which are bonded and fixed with each other through corresponding bonding keyboards. In some applications, the appropriate fixing mode is determined and selected according to actual conditions, and is not limited to a certain fixing mode.
In the embodiment of the present invention, external connection pads 22 are further disposed on the IC chip 2, and the IC chip is soldered to the electronic device through the external connection pads 22.
In the embodiment shown in FIG. 3, first, the bottom of the silicon crystal is metal-wired for other device electrical connections, i.e.: electrically connected to the IC chip; next, the back electrode 16 is formed by doping or ion implantation of the silicon crystal.
In the embodiment shown in fig. 4, a passivation layer is deposited on the membrane by forming a cavity 15 and a diaphragm 14 in the course of a silicon crystal and bonding with the crystalline silicon forming the back electrode 16, wherein the passivation layer has a thickness of 3-10 microns. Alternatively, the sacrificial layer is further deposited on the back electrode 16, and the sacrificial layer is etched to form the cavity 15 and the diaphragm 14.
In the embodiment shown in fig. 5, the silicon crystal is etched to form the cavity 12 and recess 11 of the MEMS top cap. In the embodiment shown in FIG. 6, the MEMS top cover and underlying structure are bonded together to form a MEMS chip.
In the embodiment of the invention, the MEMS chip is manufactured to realize chip-scale packaging, and different from the traditional MEMS sensor packaging process, the waterproof sensor does not need gold wire bonding, a shell, a substrate, potting adhesive, a waterproof membrane and the like. In the invention, the MEMS chip and the IC chip are bonded or welded and matched with the sealing ring to realize the water resistance of the whole device. By the design structure, the product size is smaller, meanwhile, the packaging stress caused by external packaging is avoided, and the performance of the chip is improved. Meanwhile, the passivation layer of the MEMS chip is utilized to realize the function of waterproof and liquid-proof, the traditional pouring sealant or waterproof film is not needed, and the packaging difficulty of the waterproof structure is reduced.
In an embodiment of the present invention, the present invention further provides an electronic device 4, including the waterproof sensor, in a specific embodiment, a specific structure of the waterproof sensor is the same as that of the embodiment, and is not described herein again. In the embodiment shown in fig. 7, the electronic device 4 is hermetically assembled with the MEM chip through the groove 11 and the sealing ring in the groove, and the electronic device 4 is assembled with the IC chip 2 through soldering by an external bonding pad.
According to the waterproof sensor and the electronic equipment provided by the invention, the passivation layer is arranged on the surface of the vibrating diaphragm and used for isolating the vibrating diaphragm from contacting with the outside, so that the MEMS has the waterproof and liquid-proof functions, and the problem that the traditional waterproof sensor filled with the sealant and the waterproof film is difficult to assemble is solved.
The waterproof sensor and the electronic device proposed according to the present invention are described above by way of example with reference to the accompanying drawings. However, it should be understood by those skilled in the art that various modifications can be made to the waterproof sensor and the electronic device of the present invention without departing from the scope of the present invention. Therefore, the scope of the present invention should be determined by the contents of the appended claims.
Claims (10)
1. A waterproof sensor comprises a structure formed by assembling an MEMS chip and an IC chip, and is characterized in that the MEMS chip comprises a main body structure and an upper cover layer fixed with the main body structure, wherein the main body structure comprises a vibrating diaphragm, and a passivation layer is arranged on the surface of the vibrating diaphragm;
the upper cover layer comprises a cavity communicated with the outside, the upper cover layer is arranged on the passivation layer in a covering mode, and the passivation layer is used for isolating the vibrating diaphragm from contacting with the outside.
2. The waterproof sensor of claim 1,
the body structure further comprises a back pole, wherein,
and a cavity is arranged between the back electrode and the vibrating diaphragm, the cavity and the back electrode form a capacitor.
3. The waterproof sensor of claim 2,
the upper cover layer is provided with a through hole which is used for communicating the outside with the cavity;
the through hole transmits the external pressure to the vibrating diaphragm through the cavity, so that the vibrating diaphragm vibrates to cause the change of the capacitance.
4. The waterproof sensor according to claim 1,
the body structure further comprises a silicon substrate, wherein,
the silicon substrate, the cavity, the vibrating diaphragm and the resistor form a Wheatstone resistor bridge.
5. The waterproof sensor of claim 1,
the passivation layer is deposited on the diaphragm, wherein,
the passivation layer is made of an insulating material, and the thickness of the passivation layer is 3-10 microns.
6. The waterproof sensor according to claim 1,
a groove is arranged on the upper cover layer and used for accommodating a sealing ring or sealant, wherein,
the MEMS chip is assembled with the sealing ring or the sealant and the electronic equipment through the groove.
7. The waterproof sensor according to claim 1,
the MEMS chip and the IC chip are respectively provided with corresponding internal connection bonding pads, and are welded and fixed through the internal connection bonding pads; alternatively, the first and second liquid crystal display panels may be,
the MEMS chip and the IC chip are mutually fixed in a bonding mode.
8. The waterproof sensor according to claim 1,
and the IC chip is also provided with an external bonding pad, and the IC chip is welded with the electronic equipment through the external bonding pad.
9. The waterproof sensor of claim 1,
the main body structure and the upper cover layer are mutually fixed in a bonding mode.
10. An electronic device characterized by comprising a waterproof sensor according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211186654.9A CN115752521A (en) | 2022-09-27 | 2022-09-27 | Waterproof sensor and electronic equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211186654.9A CN115752521A (en) | 2022-09-27 | 2022-09-27 | Waterproof sensor and electronic equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115752521A true CN115752521A (en) | 2023-03-07 |
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ID=85350465
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211186654.9A Pending CN115752521A (en) | 2022-09-27 | 2022-09-27 | Waterproof sensor and electronic equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115752521A (en) |
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- 2022-09-27 CN CN202211186654.9A patent/CN115752521A/en active Pending
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