EP3227653A1 - Silicon capacitive differential pressure sensor with high overload protection - Google Patents
Silicon capacitive differential pressure sensor with high overload protectionInfo
- Publication number
- EP3227653A1 EP3227653A1 EP14808977.4A EP14808977A EP3227653A1 EP 3227653 A1 EP3227653 A1 EP 3227653A1 EP 14808977 A EP14808977 A EP 14808977A EP 3227653 A1 EP3227653 A1 EP 3227653A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- silicon
- pressure transducer
- electrode
- hole
- silicon wafer
- 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.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/0041—Transmitting or indicating the displacement of flexible diaphragms
- G01L9/0072—Transmitting or indicating the displacement of flexible diaphragms using variations in capacitance
- G01L9/0073—Transmitting or indicating the displacement of flexible diaphragms using variations in capacitance using a semiconductive diaphragm
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L13/00—Devices or apparatus for measuring differences of two or more fluid pressure values
- G01L13/02—Devices or apparatus for measuring differences of two or more fluid pressure values using elastically-deformable members or pistons as sensing elements
- G01L13/025—Devices or apparatus for measuring differences of two or more fluid pressure values using elastically-deformable members or pistons as sensing elements using diaphragms
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
Pressure transducer (1) comprising: - a first outer silicon electrode (3) arranged in a plane and provided with a first through hole (13) situated on an axis (A-A) substantially perpendicular to said plane; - a second outer silicon electrode (5) arranged substantially parallel to said plane and provided with a second through hole (15) situated on an axis (A-A) substantially perpendicular to said plane; - a central silicon electrode (7) comprising an outer portion (7a) with a first thickness, said outer portion (7a) being bonded on each face to said first and said second outer silicon electrodes (3, 5) respectively by means of a respective insulating layer (9, 11), an inner portion (7c) with a second thickness, said inner portion (7c) being centred on said axis (A-A) facing each of said first and second through holes (13, 15), and an intermediate portion (7b) forming a membrane linking the inner portion (7c) to the outer portion (7a) and having a third thickness less than each of the first and second thicknesses, wherein each of said electrodes (3, 5, 7) is doped to a conductive state, and wherein each of the first and second silicon electrodes (3, 5) are adapt e d to limit the displacement of said inner portion (7c) parallel to said axis (A-A).
Description
Description
Silicon capacitive differential pressure sensor with high overload protection
Technical Field
[0001] The present invention relates to the field of pressure sensors, in particular to capacitive differential pressure sensors.
State of the art
[0002] Various types of capacitive MEMS differential pressure transducers are known in the art, and are typically of glass-silicon-glass, or silicon-silicon- silicon. Typically, these do not incorporate inherent overpressure protection, requiring other protective means to be integrated in the sensor in which the transducer is integrated. Furthermore, the common glass-silicon-glass structures require extra deposition of conductive layers on the glass elements so as to form the necessary conductive elements forming the capacitors, which increases complexity.
[0003] An object of the invention is thus to provide a simple and economic MEMS- type silicon-silicon-silicon capacitive differential pressure transducer with high overload protection.
Disclosure of the invention
[0004] This object of the invention is attained by a pressure transducer comprising a first outer silicon electrode arranged in a plane and provided with a first through hole situated on an axis substantially perpendicular to said plane, a second outer silicon electrode arranged substantially parallel to said plane and provided with a second through hole situated on an axis substantially perpendicular to said plane, and a central silicon electrode comprising an outer portion with a first thickness, said outer portion being bonded on each face to said first and said second outer silicon electrodes respectively by means of a respective insulating layer, an inner portion with a second thickness, said inner portion being centred on said axis facing each of said first and second through holes, and an intermediate portion forming a
membrane linking the inner portion to the outer portion and having a third thickness less than each of the first and second thicknesses. Each of said electrodes is doped to a conductive state, and each of the first and second silicon electrodes are adapted to limit the displacement of said inner portion parallel to said axis.
[0005] Each of the first and second outer electrodes thus forms an abutment against which the central portion of the central electrode can abut in the case of the pressure transducer being exposed an excessive pressure differential. Displacement of the inner portion is thus limited such that the stresses generated in the intermediate membrane portion of the inner electrode do not exceed the limits of the material, preventing damage to the pressure transducer.
[0006] Advantageously, said first thickness, i.e. that of the outer portion of the central electrode, is substantially equal to said second thickness, i.e. that of the inner portion of the central electrode. Simple manufacture with a minimum of micromachining/etching steps is thus possible.
[0007] Advantageously, the insulating layers are formed as annular or square rings, preferably with a width less than three times their thickness. These insulating rings serve not only to insulate the adjacent electrodes from each other, but also to separate them so as to determine, together with the thickness and thus the flexibility of the membrane portion of the central electrode, the pressure differential at which the central electrode comes into contact with the outer electrodes.
[0008] Advantageously, the insulating layers are formed of an oxide of silicon, which is easy to deposit and bonds well to the adjacent silicon.
[0009] Advantageously, each of said electrodes is provided with an electrical connection bonded directly on the silicon of the electrode, ensuring good electrical connection with the silicon.
[0010] Advantageously, the pressure transducer is bonded on a glass or ceramic plate, said plate comprising an opening in fluid communication with one of said first or second holes. The pressure transducer can thus be bonded to the plate before installation in a sensor, giving good access to the edges of
the transducer. The plate can then more easily be welded or otherwise bonded into the sensor than is possible by bonding the transducer directly therein.
[001 1] Advantageously, at least one of said through holes comprises a conical or pyramidal section narrowing towards the central silicon wafer. This permits reduction of the fluid resistance in the through hole, minimising pressure drop through the hole and permitting more accurate measurements and faster dynamic response. The conical or pyramidal section may extend through the whole thickness of the respective electrode, or through only an outer part of the thickness thereof, the remainder of said through hole being cylindrical.
[0012] The pressure transducer as defined above may be incorporated in a differential pressure sensor comprising:
- a sensor body defining a first end cavity and a second end cavity, each end cavity being closed by a respective diaphragm, the pressure transducer according being situated such that said first through hole is in fluidic communication with the first end cavity and the second through hole is in fluidic communication with the second end cavity, said end cavities being hermetically sealed from one another;
- a plurality of electrical connection pins protruding from the sensor body and being electrically connected the pressure transducer;
wherein the interior volume of the differential pressure sensor is filled with a fluid.
[0013] A sensor which is inherently overpressure protected at the level of the transducer is thus proposed, which does not need any further special overpressure protection arrangements.
[0014] Advantageously, wherein the pressure transducer is mounted on a pressure transducer support hermetically sealed to the sensor die body, a perforation in the support being in fluid communication with the second through hole in the transducer. Simple assembly is thus proposed, since the transducer can be easily mounted to the support before integration in the sensor. The pressure transducer support can be disposed in a recess provided in an
internal face of said first end cavity, giving good hermetic sealing between the edges of the support and the edges of the recess.
[0015] Advantageously, the electrical connection pins protrude into a cutout provided in a side wall of the sensor die body. These pins advantageously extend in a direction parallel to a longitudinal axis of the sensor die body.
This results in a compact construction, protecting the pins from damage, while permitting easy connection to e.g. a cable provided with a socket.
[0016] The object of the invention is also attained by a method of manufacturing a pressure transducer as defined above, this method comprising steps of:
- providing a first silicon wafer;
- etching said first through hole in the first silicon wafer so as to form said first outer silicon electrode;
- providing a second silicon wafer;
- etching said second through hole in the second silicon wafer so as to form said second outer silicon electrode;
- providing a third silicon wafer;
- anisotropically etching said third silicon wafer so as to form said intermediate portion between said outer portion and said inner portion, thereby forming said inner silicon electrode;
- depositing said insulating layers on each face of said outer portion;
- bonding said first and second outer silicon electrodes to said insulating layers.
[0017] An alternate method of manufacturing a pressure transducer as defined above, comprises steps of:
- providing a first silicon wafer;
- etching said first through hole in the first silicon wafer so as to form said first outer silicon electrode;
- providing a second silicon wafer;
- etching said second through hole in the second silicon wafer so as to form said second outer silicon electrode;
- providing a third silicon wafer;
- applying a layer of insulating material to either face of the portions of the third silicon wafer which will become said outer portion and said inner portion;
- anisotropically etching said third silicon wafer so as to form said intermediate portion between said outer portion and said inner portion, thereby forming said inner silicon electrode;
- removing undesired portions of said insulating material so as to leave said insulating layers;
- bonding said first and second outer silicon wafers to said insulating layers. Brief description of the drawings
[0018] Further details of the invention will now be described in reference to the following figures, in which:
- Fig. 1 is a cross-sectional view of a pressure transducer according to the invention;
- Fig. 2 is a cross-sectional view of a variant of a pressure transducer according to the invention;
- Fig. 3 is a cross-sectional view of a variant of a pressure transducer according to the invention; and
- Figure 4 is a perspective transparent view of a differential pressure sensor incorporating a pressure transducer according to the invention.
Embodiments of the invention
[0019] Figure 1 illustrates schematically a cross-section of a pressure transducer 1 according to the invention. Pressure transducer 1 is of silicon-silicon-silicon construction, and is principally constructed of three parallel silicon electrodes formed of structured silicon wafers, namely first outer silicon electrode 3, second outer silicon electrode 5, and central silicon electrode 7. Each silicon electrode is sufficiently doped such that its conductivity is adequate for the intended use. In the illustrated embodiment, no coatings are present on the surfaces of the electrodes 3, 5, 7 which face each other.
[0020] The two outer silicon wafers 3, 5 are positioned either side of central silicon electrode 7, and are each separated therefrom respectively via insulating
layers 9, 1 1 , which would typically be of silicon dioxide. In the illustrated embodiments, insulating layers 9, 1 1 formed as a narrow ring surrounding the membrane portion of the central silicon electrode 7 (see below), with a width parallel to the plane of the wafers ideally no more than three times its thickness. The separation between adjacent faces of central silicon electrode 7 and outer silicon electrodes 3, 5 is typically of the order of 2-3 micrometres, however other separations can be chosen according to need, and to vary the pressure at which the central portion 7c of the inner electrode 7 abuts against the corresponding outer electrode 3, 5.
[0021] The crystal orientation of the silicon of at least central silicon electrode 7 is chosen such that the required structures can be formed therein by anisotropic etching along a crystal plane at substantially 54.74° to the plane of the wafer, as is generally known. This is also the case for outer silicon electrodes 3, 5 but is not fundamental and can be dispensed with if formation of such structures is not required in these wafers.
[0022] Each outer silicon electrode 3, 5 is respectively provided with a through hole 13, 15 arranged on an axis perpendicular to the plane of the wafers 3, 5, 7, the function of which will become clearer below. These through holes 13, 15 can be etched or ground as required. The axes of the through holes 13, 15 can be the same, single axis, or can be parallel, offset axes.
[0023] Central silicon electrode 7 comprises essentially three portions: an outer portion 7a, to which insulating layers 9, 1 1 adhere, an intermediate portion 7b which is thinner than outer portion 7a and thus forms a relatively flexible membrane, and an inner portion 7c which is thicker than intermediate portion 7b. For manufacturing convenience, outer portion 7a and inner portion 7c can be of the same thickness, which minimises the number of micro-machining steps required to form the central electrode 7.
[0024] The transition from each portion to the next necessarily incorporates angled surfaces following the crystal planes. With standard silicon micro-machining technology, when viewed perpendicular to the plane, intermediate portion 7b and inner portion 7 will be square or rectangular, however more advanced manufacturing techniques will permit these portions to be circular.
[0025] Thus, a pair of cavities 23, 25 is formed either side of the central electrode 7, delimited by a face of the central electrode 7, the adjacent face of the respective outer electrode 3, 5, and the respective insulating layer 9, 1 1. Through holes 13, 15 connect respectively each of these cavities to the outside.
[0026] The various dimensions of the parts of the central electrode 7 (in particular the thickness and width of the intermediate portion 7b, and the extent of the inner portion 7c) can be chosen at will such that the displacement of the inner portion 7c, and hence the variations in capacitance, have the desired pressure response. The skilled person understands how to adjust these dimensions, and thus this aspect need not be described further.
[0027] Furthermore, each silicon electrode 3, 5, 7 is provided with an electrical connection 17, 19, 21 respectively. These electrical connection 17, 19, 21 are provided directly on the silicon, for instance as vapour-deposited aluminium layers, and are situated on non-adjacent faces of the electrodes 3, 5, 7 to prevent the risk of short-circuits. For compactness, the electrical connections 17, 19 and 21 are situated adjacent to an edge of the electrodes 3, 5, 7, preferably all to the same edge and adjacent to one another. The transducer 1 can thus be mounted flat without requiring any electrical connections on a face thereof.
[0028] In consequence, pressure sensor 1 forms a differential capacitor in the conventional manner, and thus measures differential pressure.
[0029] It should be noted that the various electrodes can be etched or machined around their peripheries in any convenient manner, for instance to provide good access to electrodes 17, 19, 21.
[0030] During manufacture, cavities 23, 25 are filled with fluid such as silicone oil, which is typically performed under vacuum so as to prevent air bubbles being formed and retained within the cavities 23, 25.
[0031] In use, this fluid is exposed to sources of pressure, typically via a membrane (see below). Since the intermediate portion 7b of central electrode 7 forms a membrane and is thus flexible, a difference in pressure between cavities 23 and 25 causes inner portion 7c of the central electrode 7 to be displaced
towards the low-pressure side, increasing the capacitance between the central electrode 7 and the outer electrode on the low-pressure side, and decreasing the capacitance between the central electrode 7 and the outer electrode on the high-pressure side. Differences of pressure can thus be measured electrically as is known. It should be noted that it is entirely possible simply to leave one cavity 23, 25 open to the air, and thus to measure gauge pressure.
[0032] In the case of an excessive pressure differential between cavities 23 and 25, inner portion 7c abuts against the low-pressure side outer electrode 3, 5 in the region of the respective through hole 13, 15, and the dimensions of the various components are chosen such that this abutment occurs before the stresses generated in the intermediate portion 7b of the central electrode 7 exceed the limits of the material. However, this gives rise to several competing issues: the strength of the outer electrodes 3, 5 in the zone immediately around the through holes 13, 15, and the resistance to fluid flow presented by the through holes 13, 15.
[0033] If the through holes 13, 15 are cylindrical, as is the case in figure 1 , the strength of the outer electrodes 3, 5 is maximised, providing the greatest resistance to overpressure. In measurements, differential overpressures of up to 150 Bar have been safely resisted. However, these cylindrical through holes 13, 15 produce resistance to fluid flow due to the viscosity of the fluid and its interaction with the walls of the through holes 13, 15. This resistance can lead to a pressure drop, particularly with rapidly-changing dynamic pressures.
[0034] Figure 2 illustrates a variant of a pressure transducer 1 in which this resistance to fluid flow has been minimised. This variant differs from that of figure 1 in that through holes 13, 15 are tapered towards central electrode 7. These tapered through holes 13, 15 are pyramidal if anisotropically etched with current technology, or conical if ground. This minimises resistance to fluid flow by keeping the channel as wide as possible for as long as possible.
In consequence, pressure drop along the through holes is minimised, improving measurement accuracy, while permitting a faster dynamic
response of the transducer. At the same time this ensures that the surface area of each outer electrode 3, 5 facing the inner portion 7c of the central electrode 7 is maintained as large as possible, and hence that the capacitance is equally maintained as large as possible.
[0035] However, such an arrangement of through holes 13, 15 results in the edges of the through holes 13, 15 being relatively weakened compared to the arrangement of figure 1 , which is increases the risk of the sharp edges of the through holes 13, 15 breaking in the case of overpressure.
[0036] Figure 3 illustrates a further variant of a pressure transducer 1 which represents a compromise solution between the variance of figures 1 and 2.
Each of the through holes 13, 15 comprises a tapering portion 13a, 15a becoming narrower is the central electrode 7 until approximately halfway through the thickness of the corresponding outer electrode 3, 5, at which point the through holes 13, 15 transition to a cylindrical section 13b, 15b through the remainder of the thickness of the corresponding electrode.
[0037] This arrangement permits the edges of the through holes 13, 15 which face the inner portion 7c of the inner electrode 7 to be supported by more material and thus be stronger and more resistant to damage, while nevertheless presenting less resistance to fluid flow than the cylindrical through holes of figure 1.
[0038] Figure 4 illustrates an exploded and transparent view of a differential pressure sensor 100 particularly adapted for use with the pressure transducer 1 of the invention.
[0039] Differential pressure sensor 100 comprises a sensor body 101 of broadly cylindrical form, made of metal or ceramic. Sensor body 101 further comprises a first end cavity 103 at a first end of sensor body 101 , and a second end cavity 105 at a second end of the sensor body 101 , opposite to the first end. End cavities 103 and 105 are joined by connecting bore 107 such that the cavities are in fluid communication with each other. As illustrated, connecting bore 107 follows the central longitudinal axis of sensor body 101 , however can equally be arranged offset therefrom. The end of the
connecting bore 107 which emerges in first end cavity 103 terminates in a recess 109, which is sized to accept a pressure transducer support 1 1 1.
[0040] Pressure transducer support 1 1 1 is made of any convenient material, in particular ceramic or glass, and comprises a perforation 1 13, formed as a through hole. Pressure transducer 1 is bonded, welded, encapsulated or otherwise attached in a fluid-tight manner to a surface of pressure transducer support 1 1 1 , such that through hole 15 aligns with perforation 1 13 and is in fluidic communication therewith. Pressure transducer support 1 1 1 is then welded, bonded or otherwise attached into recess 109 such that perforation 1 13 is in fluidic communication with connecting bore 107, and yet connecting bore 107 is sealed with respect to the first end cavity 103 and is not in fluidic communication therewith.
[0041] Through hole 13, on the other hand, is simply left exposed to the volume of first end cavity 103 and is thus in fluidic communication therewith.
[0042] Each of the end cavities 103, 105 is closed by a respective diaphragm 1 14, 1 15, welded, soldered, brazed or bonded to an end face of sensor body 101 in the standard fashion.
[0043] In order to permit introduction of pressure-transmitting fluids such as silicone oil, a pair of oil filling ports 1 17, 1 19 leading to end cavities 103, 105 respectively are provided, these ports 1 17, 1 19 being closed by ball valves 121. Naturally, other arrangements of filling ports are possible.
[0044] To avoid air bubbles when filling the sensor with fluid, this is best performed under high vacuum.
[0045] In order to permit electrical connection between the differential pressure transducer 1 and another device, three electrical connection pins 123 are provided which traverse the sensor body 101 from a cutout notch 125 provided in a sidewall of sensor body 101 and emerge in a first end cavity 103, in a direction parallel to the longitudinal axis of the sensor die body. These pins 123 are sealed to the sensor died body 101 such that no fluid can escape, and may be arranged with or without sealing bushings, may comprise entirely metal-filled passthroughs, or any other convenient
arrangement. The ends of pins 123 are, during assembly, connected to electrodes 17, 19, 21 provided on differential pressure transducer 1.
[0046] To assemble the differential pressure sensor 100, a particularly convenient sequence of operations is as follows:
[0047] 1. Sensor die body 101 is provided, with pins 1 13 and ball valves 121 already installed.
[0048] 2. Pressure transducer 1 is attached, e.g. by welding, to pressure transducer support 1 1 1 with through holes 1 13 and 15 being aligned.
[0049] 3. Pressure transducer support 1 1 1 is hermetically attached, e.g. by welding, into recess 109.
[0050] 4. Electrical connections are made between pins 1 13 and political connections 17, 19, 21 within first end cavity 103.
[0051] 5. Diaphragms 1 14 and 1 15 are attached to respective end faces of the sensor die body 101 , e.g. by welding.
[0052] 6. The differential pressure sensor 100 is placed under vacuum, and fluid such as silicone oil is introduced through ball valves 121 , thereby filling all the internal voids inside the differential pressure sensor 100, including cavities 23 and 25 inside pressure transducer 1.
[0053] Naturally, variations to this method are possible. For instance, diaphragm 1 15 can be attached to the sensor died body 101 at any convenient moment, or alternatively steps (2.) and (3.) above can be reversed.
[0054] Although the invention has been described in terms of specific embodiments, variations thereto are entirely within the ability of the skilled person without departing from the scope of the invention as defined by the claims.
Claims
ims
Pressure transducer (1) comprising:
- a first outer silicon electrode (3) arranged in a plane and provided with a first through hole (13) situated on an axis (A-A) substantially perpendicular to said plane;
- a second outer silicon electrode (5) arranged substantially parallel to said plane and provided with a second through hole (15) situated on an axis (A-A) substantially perpendicular to said plane;
- a central silicon electrode (7) comprising an outer portion (7a) with a first thickness, said outer portion (7a) being bonded on each face to said first and said second outer silicon electrodes (3, 5) respectively by means of a respective insulating layer (9, 1 1), an inner portion (7c) with a second thickness, said inner portion (7c) being centred on said axis (A-A) facing each of said first and second through holes (13, 15), and an intermediate portion (7b) forming a membrane linking the inner portion (7c) to the outer portion (7a) and having a third thickness less than each of the first and second thicknesses,
wherein each of said electrodes (3, 5, 7) is doped to a conductive state, and wherein each of the first and second silicon electrodes (3, 5) are adapted to limit the displacement of said inner portion (7c) parallel to said axis (A-A).
Pressure transducer (1) according to claim 1 , wherein said first thickness is substantially equal to said second thickness.
Pressure transducer (1 ) according to one of claims 1 -2, wherein said insulating layers (9, 1 1) are formed as annular or square rings, preferably with a width less than three times their thickness.
Pressure transducer (1 ) according to one of claims 1 -3, wherein said insulating layers (9, 1 1 ) are formed of an oxide of silicon.
5. Pressure transducer (1) according to one of claims 1 -4, wherein each of said electrodes (3, 5, 7) is provided with an electrical connection (17, 19, 21 ) bonded directly on the silicon of the electrode. 6. Pressure transducer (1 ) according to one of claims 1 -5, wherein the pressure transducer (1) is bonded on a glass or ceramic plate (1 1 1 ), said plate comprising a perforation (1 13) in fluid communication with one of said first or second holes (13, 15). 7. Pressure transducer (1) according to one of claims 1 -6, wherein at least one of said through holes (13, 15) comprises a conical or pyramidal section narrowing towards the central silicon electrode (7).
8. Pressure transducer (1) according to claim 7, wherein said conical or pyramidal section extends through the whole thickness of the respective electrode.
9. Pressure transducer according to claim 7, wherein said conical or pyramidal section (15a) extends from an outer face of the electrode and through a part of the thickness thereof, the remainder of said through hole (15b) being cylindrical.
10. Differential pressure sensor (100) comprising:
- a sensor body (101 ) defining a first end cavity (103) and a second end cavity (105), each end cavity (103, 105) being closed by a respective diaphragm (1 14, 1 15);
- a pressure transducer (1 ) according to one of claims 1-9 situated such that said first through hole (13) is in fluidic communication with the first end cavity (103) and the second through hole (15) is in fluidic communication with the second end cavity (105), said end cavities (103, 105) being hermetically sealed from one another;
- a plurality of electrical connection pins (123) protruding from the sensor body and being electrically connected to said pressure transducer (1 );
wherein the interior volume of the differential pressure sensor is filled with a fluid.
1 1. Differential pressure sensor (100) according to clainn 10, wherein the pressure transducer (1 ) is mounted on a pressure transducer support (1 1 1 ) hermetically sealed to said sensor die body (101 ), a perforation in the pressure transducer support (1 1 1) being in fluid communication with said second through hole (15).
12. Differential pressure sensor (100) according to claim 1 1 , wherein the pressure transducer support (1 1 1) is disposed in a recess provided in an internal face of said first end cavity.
13. Differential pressure sensor (100) according to one of claims 10-12, wherein said electrical connection pins (123) protrude into a cutout (125) provided in a side wall of the sensor die body (101 ). 14. Differential pressure sensor (100) according to claim 13, wherein said electrical connection pins (123) extend in a direction parallel to a longitudinal axis of the sensor die body (101 ).
15. Method of manufacturing a pressure transducer according to one of claims 1 -9, comprising steps of:
- providing a first silicon wafer;
- etching said first through hole (13) in the first silicon wafer so as to form said first outer silicon electrode (3);
- providing a second silicon wafer;
- etching said second through hole (15) in the second silicon wafer so as to form said second outer silicon electrode (5);
- providing a third silicon wafer;
- anisotropically etching said third silicon wafer so as to form said intermediate portion (7b) between said outer portion (71 ) and said inner portion (7b), thereby forming said inner silicon electrode (7);
- depositing said insulating layers (9, 1 1) on each face of said outer portion (7a);
- bonding said first and second outer silicon electrodes (3, 5) to said insulating layers (9, 1 1 ).
16. Method of manufacturing a pressure transducer according to one of claims 1 - 9, comprising steps of:
- providing a first silicon wafer;
- etching said first through hole (13) in the first silicon wafer so as to form said first outer silicon electrode (3);
- providing a second silicon wafer;
- etching said second through hole (15) in the second silicon wafer so as to form said second outer silicon electrode (5);
- providing a third silicon wafer;
- applying a layer of insulating material to either face of the portions of the third silicon wafer which will become said outer portion (7a) and said inner portion (7c); - anisotropically etching said third silicon wafer so as to form said intermediate portion (7b) between said outer portion (7a) and said inner portion (7c), thereby forming said inner silicon electrode (7);
- removing undesired portions of said insulating material so as to leave said insulating layers (9, 1 1 );
- bonding said first and second outer silicon wafers (3, 5) to said insulating layers.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/EP2014/076630 WO2016087000A1 (en) | 2014-12-04 | 2014-12-04 | Silicon capacitive differential pressure sensor with high overload protection |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP3227653A1 true EP3227653A1 (en) | 2017-10-11 |
Family
ID=52014089
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP14808977.4A Withdrawn EP3227653A1 (en) | 2014-12-04 | 2014-12-04 | Silicon capacitive differential pressure sensor with high overload protection |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP3227653A1 (en) |
| WO (1) | WO2016087000A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114459666B (en) * | 2022-02-14 | 2023-03-17 | 北京航空航天大学 | Capacitive differential pressure sensor, manufacturing method and application thereof |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5157973A (en) * | 1989-03-16 | 1992-10-27 | Process Automation Business, Inc. | Pressure sensor with integral overpressure protection |
| DE10130372B4 (en) * | 2001-06-23 | 2006-09-14 | Abb Patent Gmbh | Differential Pressure Sensor |
-
2014
- 2014-12-04 WO PCT/EP2014/076630 patent/WO2016087000A1/en active Application Filing
- 2014-12-04 EP EP14808977.4A patent/EP3227653A1/en not_active Withdrawn
Non-Patent Citations (2)
| Title |
|---|
| None * |
| See also references of WO2016087000A1 * |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2016087000A1 (en) | 2016-06-09 |
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