CN218865183U - Flow sensor chip based on MEMS technology and flow sensor - Google Patents
Flow sensor chip based on MEMS technology and flow sensor Download PDFInfo
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- CN218865183U CN218865183U CN202222567686.5U CN202222567686U CN218865183U CN 218865183 U CN218865183 U CN 218865183U CN 202222567686 U CN202222567686 U CN 202222567686U CN 218865183 U CN218865183 U CN 218865183U
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Abstract
The utility model relates to the technical field of sensors and discloses a flow sensor chip and a flow sensor based on MEMS technology, wherein the flow sensor chip based on MEMS technology comprises a micro-heater, an upstream thermopile, a downstream thermopile, a bottom medium film, a silicon substrate and a cavity; the micro heater, the upstream hot spot pile and the downstream thermopile are arranged above a bottom medium film, and the upstream thermopile and the downstream thermopile are respectively arranged on two sides of the micro heater; the silicon substrate is arranged below the bottom layer medium film, a cavity is arranged between the bottom layer medium film and the silicon substrate, and the cavity comprises a semicircular cavity. The utility model discloses a semi-circular sculpture groove is seted up on the upper portion of silicon substrate to, improve the sensitivity of thermopile, reduce cost.
Description
Technical Field
The utility model relates to a sensor technology field especially relates to a flow sensor chip and flow sensor based on MEMS technique.
Background
An MEMS sensor (Micro Electro Mechanical System ) is a System that integrates a Micro circuit and a Micro machine on a chip according to functional requirements, wherein a flow sensor chip of the MEMS generates heat by a heater in the center of the chip, an upstream thermopile and a downstream thermopile are respectively disposed on the left and right sides of the heater, when no current flows through the chip, the voltages of the upstream thermopile and the downstream thermopile are the same, when current flows through the chip, the flow is calculated according to the difference between the downstream thermopile and the upstream thermopile, and thus, the sensitivity of the flow sensor and the sensitivity of the two thermopiles to sense heat have a very large relationship.
In the prior art, in order to increase the sensitivity of the heat induced by an upstream thermopile and a downstream thermopile, a medium film and the thermopiles for supporting are generally thinned to reduce the heat conductivity, so that the temperature difference between a hot junction and a cold junction is improved, or a thermopile material with a higher Seebeck coefficient is selected.
In conclusion, the conventional thermopile has poor sensitivity and very high cost.
SUMMERY OF THE UTILITY MODEL
A primary object of the utility model is to provide a flow sensor chip and flow sensor based on MEMS technique, aim at offering semi-circular sculpture groove through the upper portion of silicon substrate to, improve the sensitivity of thermopile, reduce cost.
In order to achieve the above object, the present invention provides a flow sensor chip based on MEMS technology, which comprises a micro-heater, an upstream thermopile, a downstream thermopile, a bottom dielectric film, a silicon substrate, and a cavity;
the micro heater, the upstream hot spot stack and the downstream thermopile are arranged above the bottom medium film, and the upstream thermopile and the downstream thermopile are respectively arranged at two sides of the micro heater;
the silicon substrate is arranged below the bottom layer medium film, a cavity is arranged between the bottom layer medium film and the silicon substrate, and the cavity comprises a semicircular cavity.
Optionally, the silicon substrate is of an integrated structure, a hemispherical concave portion is arranged on a surface of the integrated structure, which is in contact with the bottom dielectric film, and the hemispherical concave portion and the bottom dielectric film form the semicircular cavity.
Optionally, the flow sensor chip further comprises: a first release hole and a second release hole;
the first release hole is arranged on the bottom layer film and is positioned between the micro-heater and the upstream thermopile, the second release hole is arranged on the bottom layer film and is positioned between the micro-heater and the downstream thermopile, and the first release hole and the second release hole are communicated with the semicircular cavity.
Optionally, the chamber comprises a funnel-shaped cavity.
Optionally, the silicon substrate is of a left-right split structure, and a first split body and a second split body of the silicon substrate are arranged at intervals to form a rectangular cavity between the first split body and the second split body;
a first quarter spherical concave part is arranged on one side of the first sub-body close to the micro-heater, a second quarter spherical concave part is arranged on one side of the second sub-body close to the micro-heater, and the first quarter spherical concave part and the second quarter spherical concave part are communicated to form a semicircular cavity;
the semicircular cavity is communicated with the rectangular cavity to form the funnel-shaped cavity.
Optionally, the bottom dielectric film is a silicon dioxide or silicon nitride material.
Optionally, the thermopile comprises a plurality of pairs of thermocouples stacked up and down and connected in series, each pair of thermocouples comprises P-type silicon and N-type silicon which are placed up and down, and a metal hot junction for connecting the P-type silicon and the N-type silicon, and the metal hot junction is positioned at one end of the P-type silicon and the N-type silicon close to the micro-heater; and intermediate medium films for electric isolation are arranged between the P-type silicon and the N-type silicon of each pair of thermocouples and between the adjacent thermocouples.
Optionally, the intermediate dielectric film is a silicon dioxide or silicon nitride material.
Optionally, the metal thermosonic material is metal aluminum.
Furthermore, to achieve the above object, the present invention also provides a sensor including the flow sensor chip based on MEMS technology as defined in any one of the above.
The utility model discloses a flow sensor chip based on MEMS technique includes micro-heater, upstream thermopile, downstream thermopile, bottom medium film, silicon substrate, cavity; the micro heater, the upstream hot spot stack and the downstream thermopile are arranged above the bottom medium film, and the upstream thermopile and the downstream thermopile are respectively arranged at two sides of the micro heater; the silicon substrate is arranged below the bottom layer medium film, a cavity is arranged between the bottom layer medium film and the silicon substrate, and the cavity comprises a semicircular cavity.
Be different from traditional flow sensor chip based on MEMS technique, through the fluid from left to right through flowing through, produce and launch the heat on semi-circular sculpture groove surface by the micro heater, gather the low reaches thermopile through the gathering principle of hemisphere type to, increase the temperature difference of upper reaches thermopile and low reaches thermopile, with the electromotive force that increases upper reaches thermopile and low reaches thermopile, the utility model discloses a semi-circular sculpture groove is seted up on the upper portion of silicon substrate, thereby, has improved the sensitivity of thermopile to a great extent to greatly reduced the cost.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of the flow sensor chip based on the MEMS technology of the present invention;
fig. 2 is a schematic diagram of a front etching structure of an embodiment of the flow sensor chip based on the MEMS technology of the present invention;
fig. 3 is a schematic diagram of a back etching structure of an embodiment of the flow sensor chip based on the MEMS technology of the present invention;
FIG. 4 is a schematic diagram of a conventional front etching structure of an embodiment of a flow sensor chip based on MEMS technology;
fig. 5 is a schematic diagram of a conventional back etching structure of an embodiment of the flow sensor chip based on the MEMS technology.
The reference numbers indicate:
the objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that all the directional indicators (such as upper, lower, left, right, front, and rear … …) in the present embodiment are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.
In this application, unless expressly stated or limited otherwise, the terms "connected," "secured," and the like are to be construed broadly, and for example, "secured" may be a fixed connection, a removable connection, or an integral part; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
In addition, descriptions in this application as to "first", "second", etc. are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit to the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between the embodiments may be combined with each other, but must be based on the realization of the technical solutions by a person skilled in the art, and when the technical solutions are contradictory to each other or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope claimed in the present application.
The utility model provides a flow sensor chip based on MEMS technique.
In an embodiment of the present invention, referring to fig. 1, fig. 1 is a schematic structural diagram of an embodiment of a flow sensor chip based on MEMS technology, where the flow sensor chip based on MEMS technology includes a micro-heater 1, an upstream thermopile 2, a downstream thermopile 3, a bottom dielectric film 4, a silicon substrate 5, and a cavity 6; the micro-heater 1, the upstream hot spot stack 2 and the downstream thermopile 3 are arranged above a bottom medium film 4, and the upstream thermopile 2 and the downstream thermopile 3 are respectively arranged on two sides of the micro-heater 1; the silicon substrate 5 is arranged below the bottom layer dielectric film 4, a cavity 6 is arranged between the bottom layer dielectric film 4 and the silicon substrate 5, and the cavity 6 comprises a semicircular cavity.
It should be noted that, in the present embodiment, the chamber includes a semicircular cavity, and may also include a third-shaped cavity or a quarter-shaped cavity.
In this embodiment, as shown in fig. 2, the front etching structural diagram of an embodiment of the present invention, when the air current flows, the heat generated by the micro-heater 1 moves to the downstream electric thermopile 2 along the air current, and the heat emitted to the concave spherical surface of the silicon substrate is totally reflected to the downstream electric thermopile, the conventional flow sensor chip cannot reflect the heat emitted by the micro-heater 1 from the bottom of the bottom dielectric film 4 to the downstream electric thermopile 2, as shown in fig. 4, the conventional front etching structural diagram of an embodiment of the present invention, the flow sensor shown in fig. 4 is a conventional front etching schematic diagram, the heat emitted by the micro-heater 1 to the surface of the conventional rectangular cavity cannot be totally reflected to the downstream electric thermopile 2, but is reflected to the surface of the silicon substrate, as shown in fig. 5, the flow sensor shown in fig. 5 is a conventional back etching schematic diagram, and the heat emitted by the micro-heater 1 to the surface of the conventional rectangular cavity is totally not reflected to the downstream electric thermopile 2, but is dissipated to the air.
The silicon substrate is of an integral structure, a hemispherical concave part is arranged on one surface of the integral structure, which is in contact with the bottom dielectric film, and the hemispherical concave part and the bottom dielectric film form the semicircular cavity.
In this embodiment, as shown in fig. 2, the front etching structure diagram of an embodiment of the present invention reflects all the heat reflected by the heat emitted to the concave spherical surface of the silicon substrate to the downstream thermopile 2 according to the spherical focusing principle of the hemispherical concave portion, so as to increase the heat received by the downstream thermopile 2, increase the temperature difference between the downstream thermopile 2 and the upstream thermopile 1, that is, increase the electromotive force difference between the downstream thermopile 2 and the upstream thermopile 1, and further improve the sensitivity of the flow sensor.
The flow sensor chip further includes: a first release hole and a second release hole;
the first release hole is arranged on the bottom layer film and is positioned between the micro-heater and the upstream thermopile, the second release hole is arranged on the bottom layer film and is positioned between the micro-heater and the downstream thermopile, and the first release hole and the second release hole are communicated with the semicircular cavity.
In this embodiment, the first release hole and the second release hole are front etching holes, and front etching of the silicon substrate 3 is performed from the first release hole and the second release hole of the chip.
The chamber includes a funnel-shaped cavity.
In this embodiment, as shown in fig. 3, the schematic diagram of the back etching structure according to an embodiment of the present invention, the semicircular cavity includes a funnel-shaped cavity, the funnel-shaped cavity can be divided into a semicircular cavity and a rectangular cavity, and the rectangular cavity can also be a regular trapezoid cavity or an inverted trapezoid cavity.
The first sub-body and the second sub-body of the silicon substrate are arranged at intervals to form a rectangular cavity between the first sub-body and the second sub-body; a first quarter spherical concave part is arranged on one side, close to the micro-heater, of the first split body, a second quarter spherical concave part is arranged on one side, close to the micro-heater, of the second split body, and the first quarter spherical concave part and the second quarter spherical concave part are communicated to form a semicircular cavity; the semicircular cavity is communicated with the rectangular cavity to form the funnel-shaped cavity.
In this embodiment, the silicon substrate is a left-right split structure, the silicon substrate 3 is etched from the first silicon substrate split body and the second silicon substrate split body of the chip at an interval, the back etching of the chip does not require the toughness of a film and does not affect the heat gathering of the hemispherical cavity to a downstream electric thermopile, the back etching adopts dry etching to manufacture a back cavity, and during process design, a mode that the opening is small and the etching opening is gradually increased is adopted for the back cavity etching process.
The bottom dielectric film is silicon dioxide or silicon nitride material.
In this embodiment, the bottom dielectric film is formed by processing an insulator material in a semiconductor-on-insulator material by using a micro-nano processing technique, where the semiconductor-on-insulator material includes a substrate, an insulator, and a semiconductor, and the substrate includes but is not limited to a semiconductor such as silicon, silicon nitride, and the like, and a compound thereof, and has a thickness of 100um to 1000um.
The thermopile comprises a plurality of pairs of thermocouples which are stacked up and down and connected in series, each pair of thermocouples comprises P-type silicon and N-type silicon which are arranged up and down, and a metal hot junction for connecting the P-type silicon and the N-type silicon, and the metal hot junction is positioned at one end of the P-type silicon and the N-type silicon close to the micro-heater; and intermediate medium films for electric isolation are arranged between the P-type silicon and the N-type silicon of each pair of thermocouples and between the adjacent thermocouples.
In the embodiment, the thermopile is formed by connecting N thermocouples in series, the output voltage is N times of the output voltage of a single thermocouple, and the sensitivity of the thermopile is improved by increasing the number of the thermocouples under the condition of not increasing the area of a chip.
The intermediate dielectric film is silicon dioxide or silicon nitride material.
In the present embodiment, the intermediate dielectric film is formed by processing an insulator material in a semiconductor-on-insulator material by a micro-scale processing technique, wherein the semiconductor-on-insulator material comprises a substrate, an insulator and a semiconductor, the substrate includes but is not limited to silicon, silicon nitride and other semiconductors and compounds thereof, and the thickness of the substrate is 10um to 1000um.
The metal thermostructural material is metal aluminum.
In this embodiment, the metal thermosonic material is aluminum metal having high thermal conductivity.
The utility model discloses a flow sensor chip based on MEMS technique includes micro-heater, upstream thermopile, downstream thermopile, bottom medium film, silicon substrate, cavity; the micro heater, the upstream hot spot pile and the downstream thermopile are arranged above a bottom medium film, and the upstream thermopile and the downstream thermopile are respectively arranged on two sides of the micro heater; the silicon substrate is arranged below the bottom layer medium film, a cavity is arranged between the bottom layer medium film and the silicon substrate, and the cavity comprises a semicircular cavity.
Be different from traditional flow sensor chip based on MEMS technique, through the fluid from left to right flow through the time, produce and launch the heat on semi-circular sculpture groove surface by the micro heater, gather the low reaches thermopile through the gathering principle of hemisphere type to, increase the temperature difference of upper reaches thermopile and low reaches thermopile, with the electromotive force that increases upper reaches thermopile and low reaches thermopile, the utility model discloses a semi-circular sculpture groove is seted up on the upper portion of silicon substrate, thereby, has improved the sensitivity of thermopile to a great extent to the cost is reduced to a great extent.
The above description is only a preferred embodiment of the present application, and not intended to limit the scope of the present application, and all modifications and equivalents of the technical solutions that can be directly or indirectly applied to other related technical fields within the spirit of the present application are included in the scope of the present application.
Claims (10)
1. A flow sensor chip based on MEMS technology is characterized by comprising a micro-heater, an upstream thermopile, a downstream thermopile, a bottom medium film, a silicon substrate and a cavity;
the micro heater, the upstream thermopile and the downstream thermopile are arranged above the bottom layer medium film, and the upstream thermopile and the downstream thermopile are respectively arranged at two sides of the micro heater;
the silicon substrate is arranged below the bottom layer medium film, a cavity is arranged between the bottom layer medium film and the silicon substrate, and the cavity comprises a semicircular cavity.
2. The MEMS technology based flow sensor chip of claim 1, wherein the silicon substrate is a unitary structure, and a hemispherical recess is formed on a surface of the unitary structure of the silicon substrate in contact with the bottom dielectric film, and the hemispherical recess and the bottom dielectric film form the semicircular cavity.
3. The MEMS technology based flow sensor chip of claim 2 wherein the flow sensor chip further comprises: a first release hole and a second release hole;
the first release hole is arranged on the bottom medium film and is positioned between the micro-heater and the upstream thermopile, the second release hole is arranged on the bottom medium film and is positioned between the micro-heater and the downstream thermopile, and the first release hole and the second release hole are communicated with the semicircular cavity.
4. The MEMS technology-based flow sensor chip of claim 1, wherein the chamber comprises a funnel-shaped cavity.
5. The MEMS technology based flow sensor chip of claim 4 wherein the silicon substrate is a left and right split structure, the first and second splits of the silicon substrate being spaced apart to form a rectangular cavity between the first and second splits;
a first quarter spherical concave part is arranged on one side, close to the micro-heater, of the first split body, a second quarter spherical concave part is arranged on one side, close to the micro-heater, of the second split body, and the first quarter spherical concave part and the second quarter spherical concave part are communicated to form a semicircular cavity;
the semicircular cavity is communicated with the rectangular cavity to form the funnel-shaped cavity.
6. A flow sensor chip based on MEMS technology as claimed in any of the claims 1 to 5 characterized in that the underlying dielectric film is a silicon dioxide or silicon nitride material.
7. The MEMS technology-based flow sensor chip of claim 6, wherein the thermopile comprises a plurality of pairs of thermocouples stacked one above the other in series, each pair of thermocouples comprising P-type silicon and N-type silicon placed one above the other, and a hot metal junction for connecting the P-type silicon and the N-type silicon, the hot metal junction being located at one end of the P-type silicon and the N-type silicon near the micro-heater; and intermediate medium films for electric isolation are arranged between the P-type silicon and the N-type silicon of each pair of thermocouples and between the adjacent thermocouples.
8. The MEMS technology based flow sensor chip of claim 7 wherein the intermediate dielectric film is a silicon dioxide or silicon nitride material.
9. The MEMS technology-based flow sensor chip of claim 7, wherein the metallic thermal bonding material is metallic aluminum.
10. A flow sensor, characterized in that it comprises a MEMS technology based flow sensor chip according to any of claims 1-9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222567686.5U CN218865183U (en) | 2022-09-27 | 2022-09-27 | Flow sensor chip based on MEMS technology and flow sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222567686.5U CN218865183U (en) | 2022-09-27 | 2022-09-27 | Flow sensor chip based on MEMS technology and flow sensor |
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| Publication Number | Publication Date |
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| CN218865183U true CN218865183U (en) | 2023-04-14 |
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| CN202222567686.5U Active CN218865183U (en) | 2022-09-27 | 2022-09-27 | Flow sensor chip based on MEMS technology and flow sensor |
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| CN (1) | CN218865183U (en) |
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