DE102013113171A1 - Piezoresistive silicon differential pressure cell and method for its production - Google Patents

Abstract

A semiconductor differential pressure measuring cell (1) comprises a measuring diaphragm (10); a first and second mating body (20, 30); wherein the measuring diaphragm (10) between the counter-bodies (20, 30) is arranged and connected to both pressure-tight, between the measuring diaphragm and the counter-bodies (20, 30) each having a pressure chamber (23, 33) is formed, which via an openings ( 24, 34) can be pressurized in the counter-bodies, the counter-bodies being symmetrical with respect to their mechanical properties relative to a mirror plane defined by the measuring diaphragm, the measuring diaphragm having a first piezoresistive transducer (12) for converting a deflection of the measuring diaphragm into an electrical signal, wherein the measuring diaphragm has a second transducer (13) for converting a state of the measuring diaphragm into an electrical signal, the transducers being arranged on opposite sides of the measuring diaphragm.

Description

The present invention relates to a piezoresistive differential pressure measuring cell, a method for their preparation.

Generic differential pressure measuring cells comprise implanted piezoresistive resistors, which are usually prepared in a Wheatstone bridge circuit on a first surface of a monocrystalline silicon measuring diaphragm, the measuring diaphragm being deflected in dependence on a pressure difference between its two surfaces depending on the pressure difference. Bridge, which is usually detected as a diagonal voltage of the bridge.

The measuring membrane is usually prepared by unilateral anisotropic etching in a Si wafer from a side of the wafer facing away from the first surface. This preparation leads to an asymmetric structure, which can cause, for example, a cross-sensitivity to static pressure.

The publication DE 10 2006 062 222 A1 discloses a piezoresistive differential pressure measuring cell with compensation of the static pressure. For this purpose, on the one hand a first group of piezoresistive resistance elements provided whose resistance values mainly depend on a caused by a pressure difference between the pending on both sides of a measuring membrane media deflection of the measuring membrane, and on the other hand, at least one further resistive element whose resistance value depends on the average static pressure applied to the measuring diaphragm. In this way, the static pressure can be determined at least so accurately that a cross-sensitivity of the differential pressure measuring cell with respect to the static pressure can be compensated.

However, an asymmetrical structure of the measuring cell can also lead to such cross-sensitivities that are not or not completely controllable with a compensation model. The implanted resistive elements and metallic interconnects for contacting the resistive elements are usually covered with a protective layer. This layer structure is not symmetrical with respect to the measuring membrane. This asymmetry can be e.g. Tension in the membrane lead, which irreversibly change over time and especially due to temperature changes. These changes can hardly be automatically corrected by a compensation model.

The disadvantages of an asymmetric sensor have already been alleviated in the past by symmetrical capacitive differential pressure measuring cells made of silicon, as in the patent application DE 10 2012 109 587 is described. However, these capacitive differential pressure cells are sensitive to isobaric static pressure which affects the transfer function of the differential pressure cell.

Differential pressure cells are usually optimized to measure small pressure differences p1-p2 at high static pressures p1, p2. It is important to find the right balance between sensitivity and overload resistance. For example, for the measuring range of the pressure difference | p1 - p2 | apply | p1 - p2 | / p1 <1%. If one of the pressures p1, p2 is omitted in a process plant, the measuring cell is loaded with 100 times the measuring range. Differential pressure transducers are known which withstand such overloads. Proven protection of the sensitive differential pressure cells is based on hydraulically switching an overload diaphragm to the measuring cell, whereby the measuring cell and the overload diaphragm are pressurized via hydraulic paths with the two pressures p1, p2 and the pressures are introduced into the hydraulic paths by separating diaphragms. An overload membrane has a sufficiently large hydraulic capacity to absorb in the event of a one-sided overload the volume of a transfer fluid in a hydraulic path so far that the separation membrane of this hydraulic path to a diaphragm bed comes into contact, so that a further increase in the differential pressure cell acting differential pressure is reliably prevented. Examples of differential pressure transducers with overload membranes are in EP 1 299 701 B1 . DE 10 2006 040 325 A1 and DE 10 2006 057 828 A1 disclosed.

However, the use of overload membranes inevitably leads to larger volume strokes of the transfer fluid and thus - with the same performance - to larger separation membrane surfaces, which has larger device dimensions, and higher costs to the consequence. In addition, the dynamics of the measuring mechanism are adversely affected by the overload membrane and the larger volume of the transfer fluid. Therefore, efforts are particularly known for capacitive differential pressure sensors to realize the overload protection for the measuring membrane by membrane beds. In this case, the measuring membrane should be supported on exceeding a limit value for a one-sided overpressure at least to the extent to the membrane bed, that the bursting voltage of the measuring membrane is not reached even with a further increase in pressure.

In particular aspherical membrane beds are suitable for this, which approximate the bending line of the measuring diaphragm at the limit value for the overpressure.

The patent US 4,458,537 discloses a capacitive differential pressure sensor with an aspheric membrane bed of glass, which is placed in a structure of coaxial rings, wherein the heights of the rings form a contour which corresponds to the bending line of the measuring diaphragm.

The publication DE 10 2009 046 229 A1 discloses a pressure sensor or differential pressure sensor with an aspheric membrane bed made of glass, which is formed by thermal sinking.

The patent US 7 360 431 B2 discloses a resistive pressure sensor or differential pressure sensor with an aspheric membrane bed prepared in silicon by grayscale lithography.

The publication DE 10 2010 028 773 A1 discloses a pressure sensor or differential pressure sensor with an aspheric membrane bed prepared in silicon by laser ablation, followed by an oxidation step and a final etch.

JP10078366A discloses a resistive semiconductor pressure sensor having a stepped membrane bed prepared in silicon.

The patent US 5,381,229 discloses a capacitive pressure sensor made of silicon with a stepped membrane bed, which approximates the bending line of the measuring membrane, wherein the envelope of the membrane bed in the central region has a larger radius of curvature than the measuring membrane.

In addition to the one-sided overload, symmetrical static pressure can also damage or destroy a differential pressure measuring cell, especially if the bursting strength of a joint between measuring diaphragm and measuring cell body is exceeded. To counteract this, hydraulic bearings of the measuring cell are known, which is acted upon the outside of the measuring cell with a sufficiently high static pressure, which counteracts the introduced into the measuring cell static pressures. Details are for example in the publication US 2009 078 054 A and in the patent US 6,581,469 B2 disclosed. However, this hydraulic storage requires a considerable design effort.

The publication DE 10 2011 006 517 A1 discloses a micromechanical differential pressure sensor having a ceramic capsule around a semiconductor differential pressure cell, thereby increasing resistance to static pressure.

Nevertheless, there is a need to further improve micromechanical differential pressure sensors, particularly with regard to the validity of the measurements they provide.

It is therefore the object of the present invention to provide an improved piezoresistive differential pressure measuring cell and a differential pressure sensor with such a differential pressure measuring cell. The object is achieved by the differential pressure measuring cell according to the independent claim 1 and the method according to the independent claim 10th

The semiconductor differential pressure measuring cell according to the invention comprises a measuring diaphragm; a first counter body; and a second counter body; wherein the measuring diaphragm is arranged between the first counter-body and the second counter-body and pressure-tightly connected to both counter-bodies, wherein between the measuring diaphragm and the first counter-body a first pressure chamber is formed, which is acted upon via a first opening in the first counter-body with a first pressure, wherein between the measuring diaphragm and the second counter body, a second pressure chamber is formed, which is acted upon via a second opening in the second counter body with a second pressure, wherein the first counter body with respect to its mechanical properties relative to a defined by the measuring diaphragm mirror plane symmetrical to the second counter body wherein the measuring diaphragm comprises a first piezoresistive transducer for converting a deflection of the measuring diaphragm into an electrical signal, wherein the measuring diaphragm has a second transducer for converting a state of the measuring diaphragm into an electrical signal, where wherein the first transducer on a first side measuring membrane is prepared, which faces the first pressure chamber, wherein the second transducer is arranged on a second side of the measuring diaphragm, which faces the second pressure chamber.

As a result, the pressure sensor according to the invention is completely symmetrical with respect to its properties determining the pressure measurement. That is, the deflection of the silicon diaphragm is the same for pressures from both sides. As a result, the resulting measurement signal is symmetrical with respect to a condition where the same pressure exists on both sides. Such a signal is easier to compensate than the signal from a single-ended pressure sensor.

In order to be able to additionally validate the measured values, two transducers are provided which determine the measured variable redundantly or diversely. Based on the evaluation of the measurement results, conclusions can be drawn about the condition of the sensor. As such, diagnostic strategies are known which are based on redundant or diversified measurements. To equip differential pressure sensors with two transducers but obviously an increased space requirement on the measuring diaphragm is required to position the transducer can. Insofar as the transducers are arranged distributed on the two sides of the measuring diaphragm, the measuring diaphragm surface need not be enlarged, despite the provision of two transducers. This advantage is significant, since in differential pressure sensors, the static pressure leads to stresses in the joints between the measuring membrane and counter-bodies, which are proportional to the membrane surface in first approximation.

In a development of the invention, the second converter is a piezoresistive converter which is used to convert a deflection of the measuring diaphragm into an electrical signal.

In a development of the invention, the first converter has a first transfer function U1 (Δp) and the second converter has a second transfer function U2 (Δp), where | (U1 (Δp) - U2 (-Δp)) / (U1 (Δp) + U2 (-Δp)) | <a, if | Δp | > 0.1 Δp _max , where Δp _max denotes a maximum differential pressure for which the measuring range of the semiconductor pressure measuring cell is specified, where a = 10%, in particular a = 4%, preferably a = 2%.

In a development of the invention, the first converter has a first transfer function U1 (Δp) and the second converter has a second transfer function U2 (Δp), where | (U1 (Δp) - U2 (-Δp)) / (U1 (Δp) + U2 (-Δp)) | > a, if | Δp | > 0.1 Δp _max , where Δp _max denotes a maximum differential pressure for which the measuring range of the semiconductor pressure measuring cell is specified, where a = 10%.

In one development of the invention, the first or the second counter-body is supported on the back with a supporting body. In a development of the invention, the support body or bodies are respectively joined to the supported counterbody.

In a development of the invention, the second converter is a capacitive converter for converting a displacement of the measuring diaphragm into an electrical signal, wherein a second surface of the measuring diaphragm which faces the second counterbody has at least one membrane electrode, and wherein the second counterbody has at least one counterelectrode electrode wherein the second transducer provides a signal which depends on the capacitance between the membrane electrode and the counter body electrode.

The method according to the invention for producing a differential pressure measuring cell, in particular a pressure measuring cell according to the invention, comprises the following steps:
Implantation of measuring resistors and their supply in a first wafer; Direct silicon bonding of a second wafer to the first side of the first wafer, wherein the second wafer has pressure feedthroughs, which are structured in particular by means of DRIE; Thinning the first wafer from a second side until only a desired membrane thickness is left; Polishing the second side of the first wafer; Implanting a second set of sensing resistors and their leads into the thinned first wafer from the second side of the first wafer; Direct silicon bonding of a third wafer to the second side of the first wafer, wherein the third wafer has pressure feedthroughs, which in particular are structured by means of DRIE; and singulating the differential pressure cells.

According to a development of the invention, the method furthermore comprises the electrical contacting of the supply lines of the resistance elements, wherein the contacting takes place in particular after the silicon direct bonding of the third wafer to the second side of the first wafer and before the separation of the differential pressure measuring cells and in particular by means of the through-silicon Via technology takes place.

According to a development of the invention, the method comprises preparing in each case at least one thermal oxide layer on one of the joining partners between the first wafer and the second wafer or the first wafer and the third wafer, wherein the oxide layer forms the joint between the joining partners.

According to one development of the invention, the oxide layer is prepared on a surface of the second or third wafer, wherein in particular the oxide layer is patterned to form a membrane bed against which the measuring membrane can rest in the event of a one-sided overload.

According to one development of the invention, the oxide layer is prepared in each case on a surface of the first wafer.

According to a development of the invention, after the implantation of the resistance elements and the supply lines, a protective layer is prepared, which in particular comprises SiO ₂ or Si ₃ N ₄ .

According to one development of the invention, the first wafer comprises an SOI wafer.

The invention will now be explained with reference to the embodiments illustrated in the drawings. It shows:

1 : A schematic longitudinal section through a first embodiment of a pressure measuring cell according to the invention;

2 : A schematic longitudinal section through a first embodiment of a pressure measuring cell according to the invention; and

3 A sequence of method steps of a first embodiment of a method according to the invention.

This in 1 illustrated, the first embodiment of a pressure measuring cell 1 includes a measuring membrane 10 , a first counter-body 20 , and a second counter body 30 , wherein the measuring membranes and the two counter-body in particular have silicon as a material.

The measuring membrane 10 has first resistance elements 12 in a first wheatstone bridge circuit on a first side of the measuring diaphragm, and second resistive elements 13 in a second wheatstone bridge circuit on a second side of the measuring membrane. The measuring membrane 10 is in each case by anodic bonding of the first side with a first counter-body 20 or the second side with a second counter body 30 along circumferential joints 22 . 32 connected. Between the first side of the measuring diaphragm and the first counterbody 20 a first measuring chamber 23 educated. The first measuring chamber 23 is through a first pressure channel 24 that goes through the first mating body 20 extends, with a first pressure acted upon. Between the second side of the measuring diaphragm and the second counterbody 30 is a second measuring chamber 33 is formed, wherein the measuring chamber 33 through a second pressure channel 24 passing through the second mating body 30 extends acted upon by a second pressure.

The resistive elements of the first and second bridge circuits are in each case via highly doped conductor tracks on both sides of the measuring diaphragm as well as through VIA technology prepared first feedthroughs 25 and second bushings 35 contacted, wherein the electrical feedthroughs the tracks in the area prepared by anodic bonding joints 22 . 32 between the measuring membrane 10 and the counter bodies 20 . 30 to contact.

The measuring membrane 10 may further comprise on both sides of a protective layer not shown here, which in particular SiO ₂ or Si ₃ N ₄ comprises.

The measuring diaphragm can have, for example, a thickness of 10 μm to 250 μm. The respective membrane thickness is ultimately a function of the deflectable membrane area, the desired differential pressure measuring range and the height of the measuring chambers 23 . 33 or the distance between measuring diaphragm and counter-bodies. This may, for example, not more than 16 .mu.m, in particular not more than 8 .mu.m, and preferably not more than 4 microns.

The deflectable membrane area enclosed by the joint is, for example, not less than 0.5 mm ² and not more than 15 mm ² , in particular not more than 5 mm ² . The opposing bodies 20 . 30 have a thickness of not less than 100 microns, especially not less than 200 microns. On the other hand, the material thickness of the counter-body is, for example, not more than 800 μm, in particular not more than 400 μm.

The counter-bodies can furthermore have a membrane bed with a contour on which the measuring membrane can be supported in the event of a one-sided overload. Such a membrane bed can be prepared for example by time-controlled undercutting a deposited on the counter-bodies, masked oxide layer, as in the unpublished patent application DE 10 2012 109 587 is described.

The counter-bodies can be supported on the back or stiffened, or the entire pressure measuring cell can be encapsulated in order to be able to withstand higher static pressures. Details are in the publications DE 10 2010 043 043 A1 . DE 2011 006 517 A1 , and in the still unpublished application DE 2012 113 033.7 disclosed.

The structure of the pressure measuring cell 1 is symmetrical at least with regard to its mechanical properties, so that temperature fluctuations or fluctuations of a static pressure applied in both measuring chambers cause practically no displacement of the zero point of the pressure measuring cell.

The two Wheatstone bridges may have the same or different transfer functions. In any case, they allow a plausibility check and monitoring of the measuring cell by comparing the respective measured values.

Insofar, as the two transducers are arranged on opposite sides of the measuring diaphragm, the additional bridge circuits can be realized without additional space requirement, which on the one hand the cost and on the other hand, the load proportional to the membrane surface of the joints 22 . 32 between the measuring membrane 10 and the counter bodies 20 . 30 limited.

This in 2 illustrated, second embodiment of a pressure measuring cell 101 includes a measuring membrane 110 , a first counter-body 120 , and a second counter body 130 , wherein the measuring membranes and the two counter-body in particular have silicon as a material.

The measuring membrane 110 has resistance elements 112 in a Wheatstone bridge circuit on a first side of the measuring membrane, and at least one membrane electrode 113 on a second side of the measuring membrane 110 on. The measuring membrane 110 is in each case by anodic bonding of the first side with a first counter-body 120 or the second side with a second counter body 130 along circumferential joints 122 . 132 connected. Between the first side of the measuring diaphragm and the first counterbody 120 a first measuring chamber 123 educated. The first measuring chamber 123 is through a first pressure channel 124 that goes through the first mating body 120 extends, with a first pressure acted upon. Between the second side of the measuring diaphragm and the second counterbody 130 is a second measuring chamber 33 is formed, wherein the measuring chamber 133 through a second pressure channel 24 passing through the second mating body 130 extends acted upon by a second pressure. The second mating body 130 also has one of the measuring membrane 110 facing counter-body electrode 114 which together with the membrane electrode forms a capacitive pressure transducer.

The resistance elements 112 the bridge circuit and the membrane electrode 113 Each of them has highly doped tracks on both sides of the measuring diaphragm as well as first bushings prepared by VIA technology 125 and second implementation 135 contacted, wherein the electrical feedthroughs the tracks in the area prepared by anodic bonding joints 122 . 132 between the measuring membrane 110 and the counter bodies 120 . 130 to contact. The counterbody electrode 114 is also via a second implementation prepared in VIA technology 135 contacted by the second mating body 130 extends.

The measuring membrane 110 may further comprise on both sides of a protective layer not shown here, which in particular SiO ₂ or Si ₃ N ₄ comprises.

With regard to the dimensioning of the measuring diaphragm and the counter body, as well as any support or encapsulation to be provided, the explanations on the first embodiment apply here accordingly.

The structure of the pressure measuring cell 101 is symmetrical at least with regard to its mechanical properties, so that temperature fluctuations or fluctuations of a static pressure applied in both measuring chambers cause practically no displacement of the zero point of the pressure measuring cell.

The differential pressure measurement takes place in this example from the management example with the Wheatstone bridge circuit of the piezoresistive resistor elements 112 , At moderate static pressures, which cause at most negligible deformations of the counter body, the measured by the capacitive pressure transducer measured value for the conditional by the differential pressure deflection of the measuring membrane still corresponds to that which is determined by the bridge circuit and is thus also a measure of the differential pressure. However, with increasing static pressures, deviations occur between the measured values of the Wheatstone bridge circuit, which essentially exclusively detects the deformation of the measuring diaphragm, and the measured values of the capacitive pressure transducer due to a deformation of the counter body. Based on these deviations, the static pressure can be determined in addition to the differential pressure. This allows at least corrections of the differential pressure determination based on the signal of the Wheatstone bridge circuit, if its transfer function depends on the static pressure.

• • Implantation 210 von Messwiderständen und deren Zuleitung in einem ersten Wafer, welcher ein SOI Wafer ist, von einer ersten Seite des ersten Wafers;
• • Optional kann eine in 3 nicht gesondert dargestellte Abscheidung einer ersten SiO₂/Si₃N₄ Schutzschicht auf der ersten Seite des ersten Wafers erfolgen. Die Schichtstärke dieser Schutzschicht kann beispielsweise 2 µm betragen.
• • Silizium-Direktbonden 220 eines zweiten Wafers mit der ersten Seite des ersten Wafers, wobei zur Vorbereitung des Silizium-Direkt-Bond Prozesseses zunächst eine erste thermische Oxidschicht für den Silizium-Direkt-Bond Prozess im Bereich der Fügestellen auf einer der Oberflächen der Fügepartner abzuscheiden ist, wobei der zweite Wafer Druckdurchführungen aufweist, die insbesondere mittels DRIE strukturiert sind;
• • Abdünnen 230 des ersten Wafers von einer zweiten Seite her, bis nur eine gewünschte Membrandicke vorhanden ist, wobei die gewünschte Membrandicke beispielsweise für ein Druckmesszelle mit einem Messbereich von +/–500 mbar beispielsweise 40 µm betragen kann, wenn die angestrebte laterale Dimension der Druckmesszelle etwa 2 mm beträgt, nach dem Abdünnen erfolgt ein Polieren der zweiten Seite des ersten Wafers;
• • Implantation 240 eines zweiten Satzes von Messwiderständen und deren Zuleitungen in den abgedünnten ersten Wafer von der zweiten Seite des ersten Wafers, um eine Druckmesszelle gemäß dem ersten Ausführungsbeispiel herzustellen;
• • Optional kann eine in 3 nicht gesondert dargestellte Abscheidung einer zweiten SiO₂/Si₃N₄ Schutzschicht auf der zweiten Seite des ersten Wafers erfolgen;
• • Silizium-Direktbonden 250 eines dritten Wafers mit der zweiten Seite des ersten Wafers, wobei zur Vorbereitung des Silizium-Direkt-Bond Prozesseses zunächst eine zweite thermische Oxidschicht für den Silizium-Direkt-Bond Prozess im Bereich der Fügestellen auf einer der Oberflächen der Fügepartner abzuscheiden ist, wobei der dritte Wafer Druckdurchführungen aufweist, die insbesondere mittels DRIE strukturiert sind;
• • Elektrische Kontaktierung 260 der Zuleitungen der Widerstandselemente, mittels Through-Silicon-Via Technologie; und
• • Vereinzeln 270 der Differenzdrucksensoren, beispielsweise mit einem Rastermaß von 2,2 mm.

This in 3 , illustrated embodiment of a method for producing a differential pressure sensor according to the invention comprises the following steps:

• • implantation 210 measuring resistors and their supply in a first wafer, which is an SOI wafer, from a first side of the first wafer;
• • Optionally, an in 3 Separately shown deposition of a first SiO ₂ / Si ₃ N ₄ protective layer on the first side of the first wafer done. The layer thickness of this protective layer may be, for example, 2 μm.
• • silicon direct bonding 220 a second wafer having the first side of the first wafer, wherein in preparation for the silicon direct bond Processes first deposit a first thermal oxide layer for the silicon direct bonding process in the region of the joints on one of the surfaces of the joining partners, wherein the second wafer has Druckdurchführungen, which are structured in particular by means of DRIE;
• • Thinning 230 of the first wafer from a second side until only a desired membrane thickness is present, wherein the desired membrane thickness, for example, for a pressure measuring cell with a measuring range of +/- 500 mbar may be 40 microns, for example, if the desired lateral dimension of the pressure measuring cell about 2 mm is, after thinning takes place a polishing of the second side of the first wafer;
• • implantation 240 a second set of measuring resistors and their leads into the thinned first wafer from the second side of the first wafer to produce a pressure measuring cell according to the first embodiment;
• • Optionally, an in 3 not separately shown deposition of a second SiO ₂ / Si ₃ N ₄ protective layer on the second side of the first wafer take place;
• • silicon direct bonding 250 a third wafer with the second side of the first wafer, wherein in preparation for the silicon direct bonding process, first a second thermal oxide layer for the silicon direct bonding process in the region of the joints on one of the surfaces of the joining partners is deposited, the third Wafer has pressure feedthroughs, which are structured in particular by means of DRIE;
• • Electrical contact 260 the leads of the resistive elements, via through silicon via technology; and
• • Seperate 270 the differential pressure sensors, for example, with a pitch of 2.2 mm.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

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• DE 102012109587 [0006, 0045]
• EP 1299701 B1 [0007]
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• US 4458537 [0010]
• DE 102009046229 A1 [0011]
• US 7360431 B2 [0012]
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• DE 102011006517 A1 [0017]
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• DE 2012113033 [0046]

Claims (14)

Semiconductor differential pressure measuring cell ( 1 ) comprising a measuring membrane ( 10 ); a first counter-body ( 20 ); and a second counter body ( 30 ); the measuring membrane ( 10 ) between the first counterbody ( 20 ) and the second counter body ( 30 ) and is pressure-tightly connected to both counter-bodies, wherein between the measuring diaphragm and the first counter-body ( 20 ) a first pressure chamber ( 23 ) is formed, which via a first opening ( 24 ) can be acted upon in the first counter-body with a first pressure, wherein between the measuring membrane ( 10 ) and the second counter body ( 30 ) a second pressure chamber ( 33 ) is formed, which via a second opening ( 34 ) is acted upon in the second counter-body with a second pressure, wherein the first counter body is in terms of its mechanical properties with respect to a defined by the measuring diaphragm mirror plane symmetrical to the second counter body, wherein the measuring diaphragm a first piezoresistive transducer ( 12 ) for converting a displacement of the measuring diaphragm into an electrical signal, wherein the measuring diaphragm comprises a second transducer ( 13 ) for converting a state of the measuring diaphragm into an electrical signal, wherein the first transducer is prepared on a first side measuring diaphragm facing the first pressure chamber, the second transducer being disposed on a second side of the measuring diaphragm facing the second pressure chamber is. A semiconductor differential pressure measuring cell according to claim 1, wherein the second transducer is a piezoresistive transducer for converting a deflection of the measuring diaphragm into an electrical signal. Semiconductor differential pressure measuring cell, according to claim 2, wherein the first converter has a first transfer function U1 (.DELTA.p) and the second converter has a second transfer function U2 (.DELTA.p), wherein | (U1 (Δp) - U2 (-Δp)) / (U1 (Δp) + U2 (-Δp)) | <a, if | Δp | > 0.1 Δp _max , where Δp _max denotes a maximum differential pressure for which the measuring range of the semiconductor pressure measuring cell is specified, where a = 10%, in particular a = 4%, preferably a = 2%. Semiconductor differential pressure measuring cell, according to claim 2, wherein the first converter has a first transfer function U1 (.DELTA.p) and the second converter has a second transfer function U2 (.DELTA.p), wherein | (U1 (Δp) - U2 (-Δp)) / (U1 (Δp) + U2 (-Δp)) | > a, if | Δp | > 0.1 Δp _max , where Δp _max denotes a maximum differential pressure for which the measuring range of the semiconductor pressure measuring cell is specified, where a = 10%. Semiconductor differential pressure measuring cell, according to one of the preceding claims, wherein the first and / or the second counter body is supported with a support body on the rear side or is. Semiconductor differential pressure measuring cell, according to one of the preceding claims, wherein the one or more supporting bodies is respectively joined to the supported counter body or are. A semiconductor differential pressure measuring cell according to claim 1, wherein the second transducer is a capacitive transducer for converting a deflection of the measuring diaphragm into an electrical signal, wherein a second surface of the measuring diaphragm facing the second counter-body has at least one membrane electrode, and wherein the second counter-body is at least one Counter body electrode, wherein the second transducer provides a signal which depends on the capacitance between the membrane electrode and the counter body electrode. Method for producing a differential pressure measuring cell, in particular according to one of the preceding claims, comprising the following steps: Implantation of measuring resistors and their supply in a first side of a first wafer; Direct silicon bonding of a second wafer to the first side of the first wafer, wherein the second wafer has pressure feedthroughs, which are structured in particular by means of DRIE; Thinning the first wafer from a second side until only a desired membrane thickness is left; Polishing the second side of the first wafer; Implanting a second set of sensing resistors and their leads into the thinned first wafer from the second side of the first wafer; Direct silicon bonding of a third wafer to the second side of the first wafer, wherein the third wafer has pressure feedthroughs, which are structured in particular by means of DRIE; and • Separation of differential pressure cells. The method of claim 8, further comprising the electrical contacting of the leads of the resistive elements, wherein the contacting in particular after the silicon direct bonding of the third wafer with the second side of the first wafer and before the separation of the differential pressure measuring cells and in particular by means of through silicon via technology. The method according to claim 9, further comprising preparing in each case at least one thermal oxide layer on one of the joining partners between the first wafer and the second wafer or the first wafer and the third wafer, wherein the oxide layer forms the joint between the joining partners. The method of claim 10, wherein the oxide layer is prepared on a surface of the second or third wafer, and wherein in particular the oxide layer is patterned to form a membrane bed, on which the measuring membrane can rest in the event of a one-sided overload. The method of claim 10, wherein the oxide layer is respectively prepared on a surface of the first wafer. Method according to one of claims 8 to 12, wherein after the implantation of the resistive elements and the leads a protective layer is prepared, which in particular SiO ₂ or Si ₃ N ₄ comprises. The method of any one of claims 8 to 13, wherein the first wafer comprises an SOI wafer.

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