MEMS FLOW SENSOR

Description

BACKGROUND OF THE INVENTION

[0001] Micro-Electro-Mechanical Systems (MEMS) based thermal sensors are known in many different configurations. A basic MEMS flow sensor includes a heater and at least one temperature sensor in the near vicinity to detect heat fluctuation as fluid moves over the heater and temperature sensor(s). The rate of fluid movement over the heater and temperature sensor(s) can be used to determine flow rate.

[0002] Existing MEMS flow sensors utilize a heater and temperature sensors on a single plane inside the flow channel on a diaphragm or suspended bridge. One known form of flow sensor is shown in Fig. 1A in which a heater 10 and temperature sensors 12 are supported on a diaphragm or membrane 14 which is disposed in a flow channel 16. Another known version of a flow sensor is shown in Fig. 1B in which a heater 10A and temperature sensors 12A are formed in a silicon plate 18 which is placed in a flow channel 16A. The sensing of temperature in only one plane limits the performance of the device. Thermal convection is omnidirectional and sensing in only a single plane is inefficient.

[0003] A raw response curve from thermopiles on a single plane MEMS sensor is typically in the shape of a square root function with sensitivity highest at low flow and gradually decreasing as flow increases. This square root shape reflects the inefficiency of the etched conductors on a single plane.

[0004] It would be beneficial to have a thermal flow sensor with improved thermal efficiency, sensitivity and measuring range.

[0005] US 2013/008263 A1 disclosed is a flowrate sensor having a flowrate detection means built into a surface mounted package. The flowrate sensor includes a fluid flow path formed in a package to guide a fluid from an inflow port provided in the lower surface of the package to an outflow port provided in the lower surface of the package through the flowrate detection means; and an external terminal provided in the outer surface of the package to guide an electric output of the flowrate detection means therethrough.

BRIEF SUMMARY OF THE INVENTION

[0006] In accordance with the invention a MEMS flow sensor is provided comprising a body having a first semiconductor substrate and a second substrate bonded together, wherein the second substrate comprises one of: a semiconductor substrate and a glass substrate; a micro flow channel etched in the body and having an etched inlet opening at a first face of the body and an etched outlet opening at an opposite face of the body, the micro flow channel extending through the body from the etched inlet opening at the first face to the etched outlet opening at the opposite face;
a film heater integral with the body and associated with the flow channel to heat fluid flowing through the flow channel; at least one film temperature sensor integral with the body and associated with the flow channel in a position spaced along the flow channel from the film heater, the at least one film temperature sensor operative to sense the temperature of fluid flowing through the flow channel, wherein the film heater and the at least one film temperature sensor form a first loop portion on the first semiconductor substrate and a second loop portion on the second substrate, and wherein the first loop portion and the second loop portion form a complete coil around the inside of the flow channel; and electronic circuitry integrated in the body and electrically connected to the film heater and the at least one film temperature sensor and operative to provide a signal representative of the rate of flow of a fluid flowing through the flow channel based at least in part on the temperature of fluid flowing through the flow channel sensed by the at least one film temperature sensor. At least one heater and one or more temperature sensors are, in one embodiment, disposed around the perimeter of the flow channel and outside of the channel. In another embodiment, a heater and one or more temperature sensors are respectively disposed outside the flow channel at the top and bottom of the channel. In further embodiments, a heater and one or more temperature sensors are located inside the flow channel on one or more surfaces thereof or around the inside perimeter of the channel. The flow sensors in accordance with the invention are preferably fabricated using wafer scale fabrication techniques which per se are known in the art.

[0007] The micro flow channel is of a size which improves the sensitivity of the thermal flow sensor since a greater percentage of the measured liquid or gas is heated in comparison with a much larger conventional flow channel in which the heater power remains constant. The micro flow channel also increases the flow impedance to thereby permit much less fluid to flow into the sensor channel. The micro channel is suitable for micro liter per minute or nano liter per minute liquid flow rates.

[0008] The MEMS micro flow channel sensors can be used in a bypass to a main flow channel to measure only a portion of the bulk flow. The high flow impedance of the micro flow channel prevents contaminants from entering the bypass channel since momentum to carry particles into the bypass channel is greatly reduced. The use of a micro flow channel in a bypass arrangement is particularly applicable where high sensitivity and contamination immunity is required. Such applications include natural gas metering, mass air flow for internal combustion engines and exhaust gas recirculation for gasoline and diesel engines.

[0009] In a preferred embodiment the MEMS flow sensor is integrated in a single chip with associated circuitry. Typically such circuitry includes signal conditioning, amplification, analog to digital conversion, memory storage and digital interface. Wireless transmitter and receiver circuitry can also be integrated into the same chip as the sensor and other circuitry.

[0010] Each silicon substrate may include one-half of a flow channel such that when the two substrates are joined or fused together, the completed flow channel is formed. In another embodiment, only one substrate contains the flow channel and the other substrate which could be either glass or silicon provides a cap over the channel. The heater and one or more temperature sensors can be configured inside or outside the flow channel and can be disposed on one or more walls of the flow channel or as loops or coils around the channel. Forming a heater and temperature sensor on more than one plane of the flow channel walls increases the magnitude of the sensor signal since heat is sensed over a larger surface area. The increase in thermal signal leads to higher sensitivity and increases the sensor dynamic range to thereby increase the power efficiency. When the width of the flow channel is larger than the height, temperature sensors and heaters located on the sidewalls are usually unnecessary as the signal gain will be minimal. The wall structures around the flow channel can have etched cavities or thinned walls to reduce heat loss through the silicon material. A thin layer of silicon nitride or other insulating material can be coated over the heater and temperature sensor surfaces to prevent oxidation.

[0011] The flow channel has an inlet and an outlet opening which are in fluid coupling relationship with respective fluid ports. The fluid coupling from the inlet and outlet of the flow channel can be direct to respective fluid ports or via intermediate fluid structures.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0012] The invention will be more fully understood from the following detailed description in conjunction with the drawings, in which:

Fig. 1A is a diagrammatic elevation view of one embodiment of a known fluid flow sensor;

Fig. 1B is a diagrammatic elevation view of another known fluid flow sensor;

Fig. 2A is an exploded pictorial view of one embodiment of a flow sensor in accordance with the invention;

Fig. 2B is a cross-sectional pictorial view of the embodiment of Fig. 2A;

Fig. 3A is a pictorial view of another embodiment of a flow sensor in accordance with the invention;

Fig. 3B is a cross-sectional pictorial view of the embodiment of Fig. 3A;

Fig. 3C is a bottom pictorial view of the embodiment of Fig. 3A and 3B;

Fig. 3D is a cross-sectional pictorial view of the embodiment of Figs. 3A-3C;

Fig. 4 is a diagrammatic elevation view of an example of a flow sensor outside of the scope of the claimed invention;

Fig. 5 is a block diagram of an integrated chip containing the flow sensor and associated circuitry in accordance with the invention;

Fig. 6A is a pictorial view of a further embodiment of the invention; and

Fig. 6B is a cutaway pictorial view of the embodiment of Fig. 6A.

DETAILED DESCRIPTION OF THE INVENTION

[0013] One embodiment of the invention is shown in Figs. 2A and 2B. A body 20 is formed by silicon substrates or structures 22 and 24 which are bonded or fused together. A flow channel 26 is formed in the body and having at one end an opening 28 formed in substrate 22 and at the opposite end an opening 30 formed in substrate 24. These openings serve as inlet or outlet holes for the fluid which is caused to flow through the flow channel 26. A heater 32 and temperature sensors 34 are etched along the perimeter of the flow channel 26 on each wall thereof to form a complete loop or coil around the inside of the flow channel. Trenches 36 are provided in each substrate 22 and 24 on each side of the flow channel to reduce the thickness of the bulk material of the substrates and thereby reduce heat losses and consequent signal losses. At least one etched opening 38 is provided through the substrates 22 and 24 for the same purpose of providing thinned sidewalls of the flow channel.

[0014] Electrical connection is made to the heater 32 and temperature sensors 34 typically by conducting vias through one or more of the walls of the flow channel and corresponding conductive paths provided on one or more of the surfaces of substrates 22 and 24.

[0015] Another embodiment is shown in Figs. 3A-3D, in which the heater and temperature sensors are etched around the outside of the flow channel. The flow channel and inlet and outlet holes and structure of substrates 22 and 24 are as shown and described in the embodiment of Figs. 2A and 2B above. In this other embodiment, the heater 32 and temperature sensors 34 are formed around the exterior surfaces outside of the flow channel.

[0016] In an alternative embodiment, the heater and temperature sensors can be etched on each wall outside of the flow channel but not connected to each other. The heaters are energized from a suitable source, and signals from the respective temperature sensors are received by the signal processing circuitry and processed to provide an indication of flow rate. In an example outside of the scope of the claimed invention, when the width to height aspect ratio of the flow channel is high, heaters and temperature sensors on the shorter sidewalls are not necessary. An arrangement having a heater and temperature sensors on the wider top and bottom walls of a body is shown in Fig 4. The body in Fig. 4 is similar to that of Figs. 3A-3D. The heater and sensors on the top and bottom substrates 22 and 24 are separately formed on trenches 36.

[0017] In one preferred embodiment, the MEMSIC flow sensor is integrated in a single chip with associated circuitry. A block diagram of the chip 50 is shown in Fig. 5. The chip includes a sensor section containing the flow sensor channel and associated openings in the heater and temperature sensors. The signal processing portion of the chip includes at least one temperature sensor, signal conditioner, analog to digital converter, amplifier, prom memory and wireless transmission and digital communication circuitry.

[0018] Figs. 6A and 6B illustrate an embodiment having a flow channel 60 extending through the body 62 from one side to the other. The heater and temperature sensors may be formed inside or outside the flow channel as described above. The body 62 is bonded to housings 64 and 66 as shown in fluid tight sealed relation. Housing 64 has a chamber 68a coupled to an opening 70a. Housing 66 has a chamber 68b coupled to an opening 70b. The openings 70a and 70b serve as inlet and outlet ports which can be coupled to tubing or fittings by which fluid is supplied to and extracted from the flow channel.

Claims

1. A MEMS flow sensor comprising:

a body (20) having a first semiconductor substrate (22) and a second substrate (24) bonded together, wherein the second substrate is one of: a semiconductor substrate and a glass substrate;

a micro flow channel (26) etched in the body (20) and having an etched inlet opening (28) at a first face of the body (20) and an etched outlet opening (30) at an opposite face of the body (20), the micro flow channel (26) extending through the body (20) from the etched inlet opening (28) at the first face to the etched outlet opening (30) at the opposite face;

a film heater (32) integral with the body (20) and associated with the flow channel (26) to heat fluid flowing through the flow channel (26);

at least one film temperature sensor (34) integral with the body (20) and associated with the flow channel (26) in a position spaced along the flow channel (26) from the film heater (32), the at least one film temperature sensor (34) operative to sense the temperature of fluid flowing through the flow channel (26),

electronic circuitry integrated in the body (20) and electrically connected to the film heater (32) and the at least one film temperature sensor (34) are operative to provide a signal representative of the rate of flow of a fluid flowing through the flow channel (26) based at least in part on the temperature of fluid flowing through the flow channel (26) sensed by the at least one film temperature sensor (34), and characterised in that the film heater (32) and the at least one film temperature sensor (34) form a first loop portion on the first semiconductor substrate and a second loop portion on the second substrate, and wherein the first loop portion and the second loop portion form a complete coil around the inside of the flow channel (26).

2. The MEMS flow sensor of claim 1, wherein at least one cavity is etched into a bulk material, the at least one cavity is configured to reduce heat loss from an etched conductor forming the film heater (32) via thermal conduction; and
the MEMS flow sensor further comprises a housing portion sealed to at least a portion of the body (20) and having a fluid cavity in fluid communication with at least one of: the inlet opening (28) and the outlet opening (30), the housing portion having a fluid port.

3. The MEMS flow sensor of claim 1 wherein the bonding process is a wafer-scaled process; and
the MEMS flow sensor further comprises a housing portion sealed to at least a portion of the body (20) and having a fluid cavity in fluid communication with at least one of: the inlet opening (28) and the outlet opening (30), the housing portion having a fluid port.

4. The MEMS flow sensor of claim 3, wherein the film heater (32) and the at least one film temperature sensor (34) are overlaid with an overlay material including at least one of: a layer silicon nitride, glass, and an organic material such as polyimide, the overlay material being configured to prevent oxidation when oxygenated gas is the fluid to measure; and to prevent a short circuit when electrically conductive liquid is the fluid to measure.

5. The MEMS flow sensor of claim 3, further comprising at least one of: an integrated signal conditioner, an integrated amplification circuit, an integrated analog to digital conversion circuit, an integrated digital interface and an integrated wireless transceiver.

6. The MEMS flow sensor of claim 1, further comprising a first housing portion sealed to a first portion of the body (20) and having a first fluid cavity in fluid communication with the inlet opening (28), the first housing portion having a first fluid port; and
a second housing portion sealed to a second portion of the body (20) and having a second fluid cavity in fluid communication with the outlet opening (30), the second housing portion having a second fluid port.

7. The MEMS flow sensor of claim 1, further comprising:

an overlay material covering the film heater (32) and the at least one film temperature sensor (34),

wherein the overlay material includes at least one of: a layer silicon nitride, glass, and an organic material such as polyimide,

wherein the overlay material is configured to prevent oxidation when oxygenated gas is the fluid to be measured.

8. The MEMS flow sensor of claim 7, further comprising a first housing portion sealed to a first portion of the body (20) and having a first fluid cavity in fluid communication with the inlet opening (28), the first housing portion having a first fluid port

9. The MEMS flow sensor of claim 1, further comprising:

an overlay material covering the film heater (32)_and the at least one film temperature sensor (34),

wherein the overlay material includes at least one of: a layer silicon nitride, glass, and an organic material such as polyimide,

wherein the overlay material is configured to prevent a short circuit when electrically conductive liquid is the fluid to be measured.

10. The MEMS flow sensor of claim 9, further comprising a first housing portion sealed to a first portion of the body (20) and having a first fluid cavity in fluid communication with the inlet opening (28), the first housing portion having a first fluid port.

11. The MEMS flow sensor of claim 1, further comprising:

an overlay material covering the film heater (32) and the at least one temperature sensor (34),

wherein the overlay material includes polyimide,

wherein the overlay material is configured to at least one of: prevent oxidation when oxygenated gas is the fluid to be measured, and prevent a short circuit when electrically conductive liquid is the fluid to be measured.

Ansprüche

1. MEMS-Durchflusssensor, umfassend:

einen Körper (20) mit einem ersten Halbleitersubstrat (22) und einem zweiten Substrat (24), die miteinander verbunden sind, wobei das zweite Substrat ein Halbleitersubstrat oder ein Glassubstrat ist;

einen Mikroströmungskanal (26), der in den Körper (20) geätzt ist und eine geätzte Einlassöffnung (28) an einer ersten Seite des Körpers (20) und eine geätzte Auslassöffnung (30) an einer gegenüberliegenden Seite des Körpers (20) aufweist, wobei sich der Mikroströmungskanal (26) durch den Körper (20) von der geätzten Einlassöffnung (28) an der ersten Seite zu der geätzten Auslassöffnung (30) an der gegenüberliegenden Seite erstreckt;

einen Filmerhitzer (32), der in den Körper (20) integriert und dem Strömungskanal (26) zugeordnet ist, um durch den Strömungskanal (26) strömendes Fluid zu erwärmen;

wenigstens einen Filmtemperatursensor (34), der in den Körper (20) integriert ist und dem Strömungskanal (26) in einer Position zugeordnet ist, die entlang des Strömungskanals (26) von dem Filmerhitzer (32) beabstandet ist, wobei der wenigstens eine Filmtemperatursensor (34) betrieben wird, um die Temperatur des durch den Strömungskanal (26) strömenden Fluids zu erfassen,

wobei eine elektronische Schaltung, die in den Körper (20) integriert und elektrisch mit dem Filmerhitzer (32) und dem wenigstens einen Filmtemperatursensor (34) verbunden ist, betrieben wird, um ein Signal bereitzustellen, das für die Strömungsrate eines durch den Strömungskanal (26) strömenden Fluids repräsentativ ist und wenigstens teilweise auf der Temperatur des durch den Strömungskanal (26) strömenden Fluids basiert, die von dem wenigstens einen Filmtemperatursensor (34) erfasst wird, und dadurch gekennzeichnet, dass der Filmerhitzer (32) und der wenigstens eine Filmtemperatursensor (34) einen ersten Schleifenabschnitt auf dem ersten Halbleitersubstrat und einen zweiten Schleifenabschnitt auf dem zweiten Substrat bilden, und wobei der erste Schleifenabschnitt und der zweite Schleifenabschnitt eine vollständige Spule um die Innenseite des Strömungskanals (26) bilden.

2. MEMS-Durchflusssensor nach Anspruch 1, wobei wenigstens ein Hohlraum in ein Schüttgutmaterial geätzt ist, wobei der wenigstens eine Hohlraum dazu eingerichtet ist, den Wärmeverlust von einem geätzten Leiter, der den Filmerhitzer (32) bildet, über Wärmeleitung zu verringern; und
der MEMS-Durchflusssensor ferner einen Gehäuseabschnitt umfasst, der mit wenigstens einem Abschnitt des Körpers (20) abgedichtet ist und einen Fluidhohlraum aufweist, der in Fluidverbindung mit wenigstens: der Einlassöffnung (28) und/oder der Auslassöffnung (30) steht, wobei der Gehäuseabschnitt einen Fluidanschluss aufweist.

3. MEMS-Durchflusssensor nach Anspruch 1, wobei der Verbindungsprozess ein Waferskalierungsprozess ist; und
der MEMS-Durchflusssensor ferner einen Gehäuseabschnitt umfasst, der mit wenigstens einem Abschnitt des Körpers (20) abgedichtet ist und einen Fluidhohlraum aufweist, der in Fluidverbindung mit wenigstens: der Einlassöffnung (28) und/oder der Auslassöffnung (30) steht, wobei der Gehäuseabschnitt einen Fluidanschluss aufweist.

4. MEMS-Durchflusssensor nach Anspruch 3, wobei der Filmerhitzer (32) und der wenigstens eine Filmtemperatursensor (34) mit einem Overlay-Material überlagert sind, das wenigstens: eine Schicht Siliziumnitrid und/oder Glas, und/oder ein organisches Material wie Polyimid einschließt, wobei das Overlay-Material dazu eingerichtet ist, Oxidation zu verhindern, wenn sauerstoffhaltiges Gas das zu messende Fluid ist, und dass es einen Kurzschluss verhindert, wenn elektrisch leitende Flüssigkeit das zu messende Fluid ist.

5. MEMS-Durchflusssensor nach Anspruch 3, ferner umfassend wenigstens: einen integrierten Signalkonditionierer und/oder eine integrierte Verstärkungsschaltung und/oder eine integrierte Analog-Digital-Wandlungsschaltung und/oder eine integrierte digitale Schnittstelle und/oder einen integrierten drahtlosen Transceiver.

6. MEMS-Durchflusssensor nach Anspruch 1, der ferner einen ersten Gehäuseabschnitt umfasst, der mit einem ersten Abschnitt des Körpers (20) abgedichtet ist und einen ersten Fluidhohlraum in Fluidverbindung mit der Einlassöffnung (28) aufweist, wobei der erste Gehäuseabschnitt einen ersten Fluidanschluss aufweist; und
einen zweiten Gehäuseabschnitt, der mit einem zweiten Abschnitt des Körpers (20) abgedichtet ist und einen zweiten Fluidhohlraum in Fluidverbindung mit der Auslassöffnung (30) aufweist, wobei der zweite Gehäuseabschnitt einen zweiten Fluidanschluss aufweist.

7. MEMS-Durchflusssensor nach Anspruch 1, ferner umfassend:

ein Overlay-Material, das den Filmerhitzer (32) und den wenigstens einen Filmtemperatursensor (34) abdeckt,

wobei das Overlay-Material wenigstens: eine Schicht Siliziumnitrid und/oder Glas und/oder ein organisches Material wie Polyimid einschließt,

wobei das Overlay-Material dazu eingerichtet ist, Oxidation zu verhindern, wenn sauerstoffhaltiges Gas das zu messende Fluid ist.

8. MEMS-Durchflusssensor nach Anspruch 7, der ferner einen ersten Gehäuseabschnitt umfasst, der mit einem ersten Abschnitt des Körpers (20) abgedichtet ist und einen ersten Fluidhohlraum in Fluidverbindung mit der Einlassöffnung (28) aufweist, wobei der erste Gehäuseabschnitt einen ersten Fluidanschluss aufweist

9. MEMS-Durchflusssensor nach Anspruch 1, ferner umfassend:

ein Overlay-Material, das die Filmerhitzer (32) und den wenigstens einen Filmtemperatursensor (34) abdeckt,

wobei das Overlay-Material wenigstens: eine Schicht Siliziumnitrid und/oder Glas und/oder ein organisches Material wie Polyimid einschließt,

wobei das Overlay-Material dazu eingerichtet ist, einen Kurzschluss zu verhindern, wenn die zu messende Flüssigkeit ein elektrisch leitendes Fluid ist.

10. MEMS-Durchflusssensor nach Anspruch 9, der ferner einen ersten Gehäuseabschnitt umfasst, der mit einem ersten Abschnitt des Körpers (20) abgedichtet ist und einen ersten Fluidhohlraum in Fluidverbindung mit der Einlassöffnung (28) aufweist, wobei der erste Gehäuseabschnitt einen ersten Fluidanschluss aufweist

11. MEMS-Durchflusssensor nach Anspruch 1, ferner umfassend:

ein Overlay-Material, das den Filmerhitzer (32) und den wenigstens einen Temperatursensor (34) abdeckt,

wobei das Overlay-Material Polyimid einschließt,

wobei das Overlay-Material dazu eingerichtet ist, wenigstens:
Oxidation zu verhindern, wenn sauerstoffhaltiges Gas das zu messende Fluid ist, und/oder einen Kurzschluss zu verhindern, wenn eine elektrisch leitende Flüssigkeit das zu messende Fluid ist.

Revendications

1. Capteur d'écoulement MEMS (microsystème électromécanique) comprenant :

un corps (20) ayant un premier substrat semi-conducteur (22) et un second substrat (24) reliés ensemble, dans lequel le second substrat est l'un parmi : un substrat semi-conducteur et un substrat en verre ;

un canal de micro-écoulement (26) gravé dans le corps (20) et ayant une ouverture d'entrée gravée (28) à une première face du corps (20) et une ouverture de sortie gravée (30) à une face opposée du corps (20), le canal de micro-écoulement (26) s'étendant à travers le corps (20) depuis l'ouverture d'entrée gravée (28) à la première face jusqu'à l'ouverture de sortie gravée (30) à la face opposée ;

un dispositif de chauffage de film (32) solidaire avec le corps (20) et associé au canal d'écoulement (26) pour chauffer le fluide s'écoulant à travers le canal d'écoulement (26) ;

au moins un capteur de température de film (34) solidaire avec le corps (20) et associé au canal d'écoulement (26) dans une position éloignée le long du canal d'écoulement (26) du dispositif de chauffage de film (32), l'au moins un capteur de température de film (34) étant configuré pour détecter la température du fluide s'écoulant dans le canal d'écoulement (26),

des circuits électroniques intégrés dans le corps (20) et électriquement raccordés au dispositif de chauffage de film (32) et l'au moins un capteur de température de film (34) sont configurés pour fournir un signal représentatif du débit d'un fluide s'écoulant dans le canal d'écoulement (26) sur la base, au moins en partie, de la température du fluide s'écoulant dans le canal d'écoulement (26), détectée par l'au moins un capteur de température de film (34), et caractérisé en ce que le dispositif de chauffage de film (32) et l'au moins un capteur de température de film (34) forment une première partie de boucle sur le premier substrat semi-conducteur et une seconde partie de boucle sur le second substrat, et dans lequel la première partie de boucle et la seconde partie de boucle forment une bobine complète autour de l'intérieur du canal d'écoulement (26).

2. Capteur d'écoulement MEMS selon la revendication 1, dans lequel au moins une cavité est gravée dans un matériau en vrac, la au moins une cavité est configurée pour réduire la perte de chaleur d'un conducteur gravé formant le dispositif de chauffage de film (32) via la conduction thermique ; et
le capteur d'écoulement MEMS comprend en outre une partie de boîtier scellée sur au moins une partie du corps (20) et ayant une cavité de fluide en communication fluidiqueavec au moins l'une parmi : l'ouverture d'entrée (28) et l'ouverture de sortie (30), la partie de boîtier ayant un orifice de fluide.

3. Capteur d'écoulement MEMS selon la revendication 1, dans lequel le processus de liaison est un processus à l'échelle de la tranche ; et
le capteur d'écoulement MEMS comprend en outre une partie de boîtier scellée sur au moins une partie du corps (20) et ayant une cavité de fluide en communication fluidique avec au moins l'une parmi : l'ouverture d'entrée (28) et l'ouverture de sortie (30), la partie de boîtier ayant un orifice de fluide.

4. Capteur d'écoulement MEMS selon la revendication 3, dans lequel le dispositif de chauffage de film (32) et le au moins un capteur de température de film (34) sont superposés avec un matériau de recouvrement comprenant au moins l'un parmi : un nitrure de silicium en couche, du verre et un matériau organique tel que la polyimide, le matériau de recouvrement étant configuré pour empêcher l'oxydation lorsque le gaz oxygéné est le fluide à mesurer ; et pour empêcher un court-circuit lorsque le liquide électriquement conducteur est le fluide à mesurer.

5. Capteur d'écoulement MEMS selon la revendication 3, comprenant en outre au moins l'un parmi : un conditionneur de signal intégré, un circuit d'amplification intégré, un circuit de conversion analogique - numérique intégré, une interface numérique intégrée et un émetteur-récepteur sans fil intégré.

6. Capteur d'écoulement MEMS selon la revendication 1, comprenant en outre une première partie de boîtier scellée sur une première partie du corps (20) et ayant une première cavité de fluide en communication fluidique avec l'ouverture d'entrée (28), la première partie de boîtier ayant un premier orifice de fluide ; et
une seconde partie de boîtier scellée sur une seconde partie du corps (20) ayant une seconde cavité de fluide en communication fluidique avec l'ouverture de sortie (30), la seconde partie de boîtier ayant un second orifice de fluide.

7. Capteur d'écoulement MEMS selon la revendication 1, comprenant en outre :

un matériau de recouvrement recouvrant le dispositif de chauffage de film (32) et le au moins un capteur de température de film (34),

dans lequel le matériau de recouvrement comprend au moins l'un parmi : du nitrure de silicium en couche, du verre et un matériau organique tel que la polyimide,

dans lequel le matériau de recouvrement est configuré pour empêcher l'oxydation lorsque le gaz oxygéné est le fluide à mesurer.

8. Capteur d'écoulement MEMS selon la revendication 7, comprenant en outre une première partie de boîtier scellée sur une première partie du corps (20) et ayant une première cavité de fluide en communication fluidique avec l'ouverture d'entrée (28), la première partie de boîtier ayant un premier orifice de fluide.

9. Capteur d'écoulement MEMS selon la revendication 1, comprenant en outre :

un matériau de recouvrement recouvrant le dispositif de chauffage de film (32) et le au moins un capteur de température de film (34),

dans lequel le matériau de recouvrement comprend au moins l'un parmi : un nitrure de silicium en couche, du verre et un matériau organique tel que la polyimide,

dans lequel le matériau de recouvrement est configuré pour empêcher un court-circuit lorsque le liquide électriquement conducteur est le fluide à mesurer.

10. Capteur d'écoulement MEMS selon la revendication 9, comprenant en outre une première partie de boîtier scellée sur une première partie du corps (20) et ayant une première cavité de fluide en communication fluidique avec l'ouverture d'entrée (28), la première partie de boîtier ayant un premier orifice de fluide.

11. Capteur d'écoulement MEMS selon la revendication 1, comprenant en outre :

un matériau de recouvrement recouvrant le dispositif de chauffage de film (32) et le au moins un capteur de température (34),

dans lequel le matériau de recouvrement comprend de la polyimide,

dans lequel le matériau de recouvrement est configuré pour au moins l'un parmi : empêcher l'oxydation lorsque le gaz oxygéné est le fluide à mesurer, et empêcher un court-circuit lorsque le liquide électriquement conducteur est le fluide à mesurer.

Drawing