EP3052915A1 - Mems chip, measuring element and pressure sensor for measuring a pressure - Google Patents

Mems chip, measuring element and pressure sensor for measuring a pressure

Info

Publication number
EP3052915A1
EP3052915A1 EP14789767.2A EP14789767A EP3052915A1 EP 3052915 A1 EP3052915 A1 EP 3052915A1 EP 14789767 A EP14789767 A EP 14789767A EP 3052915 A1 EP3052915 A1 EP 3052915A1
Authority
EP
European Patent Office
Prior art keywords
measuring
mems chip
mems
cavity
pressure
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Withdrawn
Application number
EP14789767.2A
Other languages
German (de)
French (fr)
Inventor
Stéphane KÜHNE
Claudio Cavalloni
Andreas Goehlich
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kistler Holding AG
Original Assignee
Kistler Holding AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Kistler Holding AG filed Critical Kistler Holding AG
Publication of EP3052915A1 publication Critical patent/EP3052915A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
    • G01L19/14—Housings
    • G01L19/147—Details about the mounting of the sensor to support or covering means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
    • G01L19/06—Means for preventing overload or deleterious influence of the measured medium on the measuring device or vice versa
    • G01L19/0627—Protection against aggressive medium in general
    • 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
    • G01L9/0001—Transmitting or indicating the displacement of elastically deformable gauges by electric, electro-mechanical, magnetic or electro-magnetic means
    • G01L9/0005—Transmitting or indicating the displacement of elastically deformable gauges by electric, electro-mechanical, magnetic or electro-magnetic means using variations in capacitance
    • 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
    • G01L9/0042—Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms
    • G01L9/0045—Diaphragm associated with a buried cavity
    • 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
    • G01L9/0042—Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms
    • G01L9/005—Non square semiconductive diaphragm
    • 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
    • G01L9/0051—Transmitting or indicating the displacement of flexible diaphragms using variations in ohmic resistance
    • G01L9/0052—Transmitting or indicating the displacement of flexible diaphragms using variations in ohmic resistance of piezoresistive elements
    • G01L9/0054—Transmitting or indicating the displacement of flexible diaphragms using variations in ohmic resistance of piezoresistive elements integral with a semiconducting diaphragm

Definitions

  • the present invention relates to a micro-electro-mechanical system chip (EMS chip) for measuring a pressure in a pressure chamber, comprising a MEMS substrate and a carrier substrate, which are bonded together flat along its longitudinal axis A, wherein the MEMS chip Having measuring range with electromechanical measuring means and connected via lines with the measuring range Kunststofftechniks- area with contacts.
  • the MEMS chip is rod-shaped and the measuring region and the contacting region are spaced apart in the direction of the longitudinal axis by a lead-through region.
  • the invention also relates to a measuring element and a pressure sensor comprising such a MEMS chip.
  • MEMS chips Micro-Electro-Mechanical Systems combine electron! ke learning duck and micromechanical structures on a semiconductor chip and process electrical and mechanical ⁇ infor mation. They are therefore used for sensors, actuators and others.
  • MEMS chips of the type described above are exposed with their measuring range to the pressure chamber, wherein corresponding 'measuring signals which are recorded in the pressure chamber can be removed from the contacts.
  • Such MEMS chips are suitable for the pressure-tight arrangement in an execution tion, which is formed by a full enveloping the surface of the feedthrough region 11 normal to the longitudinal axis ⁇ .
  • MEMS chips have a cavity in the carrier substrate in the measuring region which is closed by a silicon-on-insulator (SOI) wafer, a measuring bridge within In addition, the SOI wafer is designed with a reduced thickness in the entire front area of the MEMS chip so that it acts as a membrane.
  • SOI silicon-on-insulator
  • the object of the present invention is to describe a MEMS chip, a measuring element and a pressure sensor for pressure measurements at a high ambient temperature, in particular above 200 ° C., whereby the manufacture of such a MEMS chip is simplified. should be at the same time improving the reproduction of given sensitivities.
  • a MEMS chip described at the outset whose electromechanical measuring means are designed such that the MEMS substrate has a cavity forming a blind hole whose edge forms a membrane in the MEMS substrate and a measuring bridge of piezoresistive elements on the side facing away from the cavity
  • This membrane is arranged, wherein the MEMS substrate is bonded to the side facing the cavity of the carrier substrate on the carrier substrate, so that the carrier substrate forms a bottom wall of the cavity formed below the membrane.
  • the rigidity of the membrane can thus be precisely adjusted.
  • the thickness of the membrane is always identical, since the blind hole extends to an oxide layer in the MEMS substrate, which acts as an etch stop.
  • Another advantage is that no cavity has to be formed in the carrier substrate.
  • the lines can be arranged on the surface of the MEMS substrate, which has proven to be simpler than their guidance between the two layers.
  • Such MEMS chips are easy to produce as wafers and saw into the individual parts, resulting in chips with rectangular cross-sections that are easy to handle.
  • Advantageous embodiments are disclosed in the dependent claims.
  • a measuring element and from it a pressure sensor can be formed.
  • the result is a compact design of the MEMS chip and a measuring element formed therefrom, wherein a diaphragm, a cavity concluding used as electromechanical measuring means.
  • the mechanical stress induced by the deflection of the membrane is used.
  • the membrane can bend for this purpose because it is adjacent to the cavity and does not rest.
  • the stiffness of the membrane is defined by the open area of the cavity adjacent to the membrane.
  • the media separation in the installed measuring element takes place in the region of a retaining ring, which is part of the measuring element.
  • the measuring element according to the invention can be used in particular for high-temperature pressure sensors in the automotive industry, in aviation, for gas turbines, technical processes in gas and oil production, and in geothermal energy.
  • 2a shows a longitudinal section of an inventive MEMS chip with evacuated cavity, suitable for absolute pressure measurement
  • 2b shows a longitudinal section of another inventive MEMS chip with channel, suitable for relative pressure measurement
  • FIG. 2c shows a longitudinal section of a further MEMS chip according to the invention with channel and further closed cavity
  • 3a shows a plan view of an inventive measuring element with MEMS chip and retaining ring
  • 3b is a front view of the measuring element according to FIG.
  • Fig. 3c is a partial section through an inventive
  • a pressure sensor wherein a housing surrounds the measuring element according to the invention and a connecting cable is laid from the contacting area out of the housing;
  • FIG. 4a shows a longitudinal section of an inventive measuring element with a cavity and fixed clamping contact.
  • FIG. 4b shows a longitudinal section of a measuring element according to the invention with a channel adjoining the cavity and with a fixed clamping contact. Ways to carry out the invention
  • a part of the measuring element according to the invention presented here for measuring a pressure at high temperatures, preferably greater than 200 ° C., is a MEMS chip 3 as shown in FIG. 1, which is substantially rod-shaped.
  • the MEMS chip 3 comprises in. Area of a first end of a measuring area 4 and in the region of a second end a contacting region 6.
  • electromechanical measuring means are arranged in the measuring region 4 on a longitudinal surface of the MEMS chip 3 arranged.
  • these electromechanical measuring means comprise a membrane 7, which is doped with a plurality of piezoresistive elements 2, which are formed into a measuring bridge 19. From the measuring bridge 19, a plurality of lines 8 are arranged extending from the measuring region 4 to the contacting region 6 along the longitudinal surface of the MEMS chip 3.
  • the lines 8 open into a plurality of contacts 16 in the contacting region 6.
  • the lines 8 open into a plurality of contacts 16 in the contacting region 6.
  • the contacting region 6 is outside the pressure chamber D, in which the pressure is to be determined.
  • FIGS. In the sectional views along the longitudinal axis A of the MEMS chip 3, different embodiments of the MEMS chip 3 are shown in FIGS. All MEMS chips 3 are each formed by a MEMS substrate 30 and a carrier substrate 31.
  • the MEMS chip 3 is an SOI-Si chip which is made of the MEMS substrate 30, preferably as an SOI substrate 30, and is formed on the carrier substrate 31 in the form of an Si carrier substrate 31.
  • the MEMS substrate 30 and the carrier substrate 31 are arranged in a flat manner along their longitudinal axis A bonded together.
  • All MEMS chips 3 have a cavity 5 arranged in the measuring region 4, which is recessed from the MEMS substrate 30 or etched out of it.
  • Piezoresistive elements 2 are produced by etching, doping and / or coating of the substrates 30, 31.
  • the membrane 7 forms the top surface of the cavity 5 and thus closes off the cavity 5 in a pressure-tight manner from the side facing away from the substrate 31.
  • the membrane 7 is arranged to extend in a plane parallel to the longitudinal axis A of the MEMS chip 3.
  • the bottom wall 50 of the cavity 5 is formed by the carrier substrate 31. Since both substrates 30, 31 are connected to each other in a pressure-tight, non-detachable manner, the cavity 5 is closed.
  • the wall thickness of the bottom wall 50 is greater by a multiple than the thickness of the membrane 7.
  • the membrane 7 with the measuring bridge 19 is preferably designed as a thin-film SOI membrane with piezoresistors 2. This measuring bridge 19 is arranged outside the cavity 5, facing away from the substrate 31 on the outer surface of the membrane 7.
  • a vacuum is formed in the closed cavity 5.
  • the production space is evacuated for this purpose and means are provided for keeping the vacuum in the cavity long-term.
  • the cavity 5 is not evacuated, but provided with a channel 21 extending in the direction of the contacting region 6, which is opened through an opening 210 to atmospheric conditions.
  • the relative pressure or differential pressure can be measured.
  • the channel 21 terminates in a further closed cavity 12.
  • This is preferably arranged in the contacting region 6 and, contrary to the illustration, can be made much larger than the first cavity 5. Since the entire vacuumized The space of the cavity 5 is much larger in this arrangement, the vacuum is more stable, even if some gases diffuse into the cavity 5.
  • a getter 13 can be arranged in the further cavity 12 in order to obtain the vacuum as long as possible.
  • the channel 21 can also be arranged in the MEMS substrate 30, contrary to the illustration in FIG. 2 c.
  • the further cavity 12 and the channel 21 can be arranged independently of one another optionally in the MEMS substrate 30 or in the carrier substrate 30.
  • a gap forms, which acts as a channel 21, and optionally ends in a second cavity 12 or as an opening 210 in the environment.
  • the membrane 7 is always formed from the MEMS substrate 30, whereby an open cavity 5, a blind hole in the MEMS substrate 30 is formed.
  • the blind hole in the MEMS substrate 30 is provided on the side of the diaphragm 7 facing away from the carrier substrate 31 and points away from the carrier substrate 31.
  • the blind hole forming cavity 5 is steep-walled, wherein the walls are substantially perpendicular to the membrane 7. This has the advantage that the size of the cavity 5 is more accurate can be reproduced and the cavity 5 claimed less space overall.
  • the membrane 7 is limited to the cavity 5 through an oxide layer.
  • the oxide layer serves as an etch stop, whereby the membrane 7 can always be made in the same thickness.
  • a further silicon layer is generally applied adjacent to the oxide layer and extends over the entire MEMS substrate 30.
  • the piezoresistive elements 2 are designed as resistors in the membrane 7, in particular by doping in silicon. In order to insulate the resistors 2 from the surrounding silicon, this silicon can either be etched away or the resistors can be isolated from the surrounding silicon by a border of trench-shaped oxide layers.
  • the electromechanical measuring means are always designed such that the MEMS substrate 30 has a cavity 5, the bottom of which forms a membrane 7 in the MEMS substrate 30, the measuring bridge 19 consisting of piezoresistive elements 2 the cavity 5 side facing away from this membrane 7 is arranged. As soon as a pressure on the diaphragm 7 occurs, it bends. The resistors 2 can detect this bending by changing the mechanical stress and give corresponding signals via the lines 8 to the contacts 16.
  • FIG. 3 a shows a measuring element 10 according to the invention, comprising a MEMS chip 3 with the measuring area 4 and the contacting area 6, which here in one embodiment Retaining ring 1, which is placed between the two areas 4,6 arranged and permanently attached pressure-tight.
  • the retaining ring 1 is executed closed and forms part of the implementation of the measuring element 10.
  • the MEMS chip 3 is guided in the direction of its longitudinal axis A through the retaining ring 1, so that a part of the MEMS chip 3 is within the retaining ring 1 or from this is wrapped.
  • the measuring area 4 and the contacting area 6 project out of the retaining ring 1 in different directions, and the retaining ring 1 approximately surrounds the central area of the MEMS chip 3.
  • the retaining ring 1 can be seen, which completely surrounds the MEMS chip 3.
  • FIG. 3c A complete pressure sensor S according to the invention is shown in FIG. 3c.
  • This comprises a measuring element 10 comprising the MEMS chip 3 and the retaining ring 1, a enclosing housing 9 and a wiring 14.
  • the housing 9 extends parallel to the longitudinal axis A of the MEMS chip 3 and serves to protect the measuring element 10. Between the measuring Area 4 and the contacting region 6 holds the retaining ring 1, the MEMS chip 3, which it encloses in its circumference.
  • the measuring element 10 is permanently connected to the housing 9, in particular the measuring element 10 is welded to the retaining ring 1 with the housing 9 pressure-tight.
  • the retaining ring 1 and the housing 9 are preferably made of steel.
  • the housing 9 has, in an end face, at least one housing opening 90, through which the measuring element 10 in the measuring area 4 can be brought into contact with the medium in a pressure space D.
  • a plurality of housing openings 90 is recessed from the end wall of the housing 9 or the end wall is formed as a grid or sieve.
  • sealing means are provided, preferably configured in the form of a front seal or behind the thread in the form of a shoulder seal.
  • a wiring 14 is wired to the contacts 16 at the contacting area 6 of the measuring element 10, wherein the wiring 14 forms part of the pressure sensor S. Due to the design of the pressure sensor S with the wiring 14, the pressure sensor S directly, for example, in an exhaust system of an internal combustion engine, installed and a readout electronics just outside the pressure chamber D and the measuring area 4 are connected sufficiently trouble-free. Depending on the customer's request, a pressure sensor S with encapsulated measuring element 10 and suitable connecting means on the housing 9, for example in the form of an external thread 91, can be made completely wired and ready for connection.
  • FIGS. 4a and 4b are used. They each show a longitudinal section through a measuring element 10 with MEMS chip 3 and molded cavity 5, respectively. a longitudinal section through a measuring element 10 with MEMS chip 3, molded cavity 5 and adjacent channel 21. Otherwise, the measuring elements 10 are of identical design. - -
  • the MEMS chip 3 is cast in a retaining ring 1 with a potting compound 20 and is therefore mechanically stable.
  • the potting compound 20 surrounds the MEMS chip 3 along the outer circumference in a bushing region 11 completely and sealingly.
  • the potting compound 20 permanently connects the MEMS chip 3 in the feedthrough region 11 to the retaining ring 1, the retaining ring 1 and the potting compound 20 forming a partial encapsulation of the MEMS chip 3.
  • the lead-through region 11 and thus the casting compound 20 are arranged between the measuring region 4 and the contacting region 6 along the longitudinal axis A.
  • the measuring area 4 is in use in a pressure chamber D, which is to be measured, while the contacting area 6 is in use in an environment with ümbuchstik.
  • the pressure chamber D is separated by a wall, shown in Figures 4 by a gray bar from the environment with ambient pressure.
  • the retaining ring 1 and the potting compound 20 thus form a pressure-tight passage, wherein instead of attached disadvantageous bonding wires here, the entire body of the MEMS chip 3 is performed by the retaining ring 1 and secured with the potting compound 20.
  • the retaining ring 1 is used here for easy handling of the measuring element 10, since the measuring element 10 can be inserted simply by ' contact with the retaining ring 1 in a pressure chamber D, without being acted upon the measuring area 4.
  • the measuring element 10 can be attached directly pressure-tight to the wall of the pressure chamber D. If a housing 9, as shown in Figure 3c, attached to the retaining ring 1, an indirect attachment of the retaining ring 1 on the wall of the pressure chamber D via the housing 9 is possible.
  • the retaining ring 1 is executed in the figures 4 with a thickening 100, which serves as a stop in the attachment of the housing 9 on the retaining ring 1 or the fixation of the retaining ring 1 directly to the wall of the pressure chamber D.
  • the measuring element 10 can be easily and safely gripped on the retaining ring 1 and introduced into a hole in the wall of the pressure chamber D and fixed there to the retaining ring 1.
  • the retaining ring 1 is designed to be only slightly longer in the direction of the longitudinal axis A than the bushing area 11 in which the potting compound 20 is located. In further embodiments, the retaining ring 1 protrude beyond the lead-through region 11 significantly extended in the direction of the measuring region 4, or project beyond the entire measuring region 4, whereby the MEMS chip 3 is additionally protected.
  • potting compound 20 an electrically insulating or conductive mass with the smallest possible coefficient of thermal expansion, in particular glass, ceramic or an adhesive can be used.
  • a passivation layer 32 is arranged here, in particular an atomic layer deposition passivation layer 32 ALD passivation layer 32 should be applied to sensitive surfaces that are exposed to the aggressive medium depending on the intended use.
  • clamping contact 17 can be contacted with the contacts 16 simply and easily on the atmosphere side of the MEMS chip 3.
  • measuring element 10 according to FIG. 4 a can be used to measure the absolute pressure
  • measuring element 10 of the same design as in FIG. 4 b can be used for differential pressure measurement, except for the channel 21.
  • a MEMS chip 3 comprising a semiconductor material composite comprising a MEMS substrate 30 and a carrier substrate 31 is first produced.
  • the contacts 16, the lines 8, the measuring bridge 19, the piezoresistive elements 2, as well as the membrane 7 are already to be arranged in the substrate preparation and to fix the semiconductor substrates 30, 31 to each other.
  • the MEMS chip 3 is guided by the retaining ring 1 in the direction of the longitudinal axis A and the retaining ring 1 by means of potting compound 20 on the surface of the MEMS chip 3 fully pressure-tight fixed, the gap between the surface of the MEMS chip 3 and inner surface of the retaining ring 1 is completely filled, resulting in a pressure-tight attachment.
  • the potting compound 20 is arranged in the leadthrough region 11 between the measuring region 4 and the contact area 6.
  • the outer edge surfaces of the MEMS chip 3 are shown executed broken. Such an optional embodiment of the outer edge surfaces of the MEMS chip 3 is a possibility to reduce the edge stresses, especially in the region of the retaining ring 1.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Measuring Fluid Pressure (AREA)
  • Pressure Sensors (AREA)
  • Micromachines (AREA)

Abstract

Micro-electro-mechanical system chip (MEMS chip) for measuring a pressure in a pressure space (D), comprising a MEMS substrate (30) and a carrier substrate (31) which are bonded to one another in a two-dimensional manner, wherein the MEMS chip (3) is in the form of a rod and has a measuring region (4) with electromechanical measuring means, then a bushing region (11), then a contact-making region (6) which is connected to the measuring region (4) via lines (8) and has contacts (16), and wherein the MEMS chip (3) in the bushing region (11) is suitable for pressure-tight arrangement in a bushing. According to the invention, the electromechanical measuring means are configured in such a manner that the MEMS substrate (30) has a cavity (5) forming a blind hole, the edge of which forms a membrane (7) in the MEMS substrate (30), and a measuring bridge (19) comprising piezoresistive elements (2) on that side of this membrane (7) which faces away from the cavity (5). The MEMS substrate (30) is bonded to the carrier substrate (31) with the side of the cavity (5) facing the carrier substrate (31), with the result that the carrier substrate (31) forms a bottom wall (50) of the cavity (5) formed under the membrane (7).

Description

MEMS-CHIP, MESSELEMENT UND DRUCKSENSOR ZUM MESSEN EINES MEMS-CHIP, MEASURING ELEMENT AND PRESSURE SENSOR FOR MEASURING ONE
DRUCKS PRESSURE
Technisches Gebiet Technical area
Die vorliegende Erfindung betrifft einen Micro-Electro- Mechanical System Chip ( EMS-Chip) zum Messen eines Druckes in einem Druckraum, umfassend ein MEMS-Substrat und ein Trägersubstrat, die flächig entlang ihrer Längsachse A aufeinander gebondet sind, wobei der MEMS-Chip einen messenden Bereich mit elektromechanischen Messmitteln und einen über Lei- tungen mit dem messenden Bereich verbundenen Kontaktierungs- bereich mit Kontakten aufweist. Der MEMS-Chip ist stabförmig ausgestaltet und der messende Bereich und der Kontaktierungs- bereich sind in Richtung Längsachse durch einen Durchführungsbereich voneinander beabstandet. Die Erfindung betrifft ebenfalls ein Messelement sowie einen Drucksensor umfassend einen solchen MEMS-Chip. The present invention relates to a micro-electro-mechanical system chip (EMS chip) for measuring a pressure in a pressure chamber, comprising a MEMS substrate and a carrier substrate, which are bonded together flat along its longitudinal axis A, wherein the MEMS chip Having measuring range with electromechanical measuring means and connected via lines with the measuring range Kontaktierungs- area with contacts. The MEMS chip is rod-shaped and the measuring region and the contacting region are spaced apart in the direction of the longitudinal axis by a lead-through region. The invention also relates to a measuring element and a pressure sensor comprising such a MEMS chip.
Stand der Technik State of the art
MEMS-Chips (Micro-Electro-Mechanical Systems) vereinen Elektron! k-e lernente und mikromechanische Strukturen auf einem Halbleiterchip und können elektrische und mechanische Infor¬ mationen verarbeiten. Sie werden daher für Sensoren, Aktoren u. a. eingesetzt. MEMS chips (Micro-Electro-Mechanical Systems) combine electron! ke learning duck and micromechanical structures on a semiconductor chip and process electrical and mechanical ¬ infor mation. They are therefore used for sensors, actuators and others.
Im Betriebszustand werden MEMS-Chips oben beschriebener Art mit ihrem messenden Bereich dem Druckraum ausgesetzt, wobei entsprechende' Messsignale, die im Druckraum aufgenommen werden, von den Kontakten abnehmbar sind. Derartige MEMS-Chips sind geeignet zur druckdichten Anordnung in einer Durchfüh- rung, welche durch ein vollumfängliches Umhüllen der Oberfläche des Durchführungsbereichs 11 normal zur Längsachse Ä ausbildbar ist. In the operating state, MEMS chips of the type described above are exposed with their measuring range to the pressure chamber, wherein corresponding 'measuring signals which are recorded in the pressure chamber can be removed from the contacts. Such MEMS chips are suitable for the pressure-tight arrangement in an execution tion, which is formed by a full enveloping the surface of the feedthrough region 11 normal to the longitudinal axis Ä.
Bekannte Ausführungen solcher MEMS-Chips sind beispielsweise in der WO 2004/081510 AI oder auch in der Publikation von Birkelund K et al: „High pressure Silicon sensor with low- cost packaging", SENSORS AND ACTUATORS A, ELSEVIER SEQUOIA S.A., LAUSANNE, CH, Bd. 92, Nr. 1-3, S. 16-22 beschrieben. Solche MEMS Chips weisen im messenden Bereich eine Kavität im Trägersubstrat auf, die von einem Silicon-on-Insulator (SOI) Wafer geschlossen werden, wobei eine Messbrücke innerhalb der Kavität auf dem SOI Wafer angebracht ist. Der SOI Wafer ist zudem im gesamten vorderen Bereich des MEMS Chips mit einer reduzierten Dicke ausgestaltet, sodass dieser dort als Memb- ran wirkt. Known embodiments of such MEMS chips are described, for example, in WO 2004/081510 A1 or also in the publication by Birkelund K et al: "High-pressure silicone sensor with low-cost packaging", SENSORS AND ACTUATORS A, ELSEVIER SEQUOIA SA, LAUSANNE, CH 92, No. 1-3, pages 16 to 22. Such MEMS chips have a cavity in the carrier substrate in the measuring region which is closed by a silicon-on-insulator (SOI) wafer, a measuring bridge within In addition, the SOI wafer is designed with a reduced thickness in the entire front area of the MEMS chip so that it acts as a membrane.
Die Steifigkeit dieser Membran, die für die Empfindlichkeit des MEMS-Chips resp. des Messelements verantwortlich ist, wird nun über die verbleibende Restdicke des SOI Wafers im messenden Bereich angepasst. Dies ist relativ aufwändig, da die Dickenreduktion in der Regel durch gezieltes Abätzen der Siliziumschicht erzielt wird: je länger geätzt wird, desto dünner wird die Membranschicht. Da diese Ätzzeiten aber sehr kurz sind, gestaltet sich eine genaue Reproduktion einer vorgegebenen Membransteifigkeit als äusserst schwierig. Darstellung der Erfindung The stiffness of this membrane, which responds to the sensitivity of the MEMS chip. of the measuring element is now adjusted over the remaining thickness of the SOI wafer in the measuring range. This is relatively complicated, since the thickness reduction is usually achieved by targeted etching of the silicon layer: the longer etched, the thinner the membrane layer. However, since these etching times are very short, accurate reproduction of a given membrane rigidity is extremely difficult. Presentation of the invention
Aufgabe der vorliegenden Erfindung ist es, ein MEMS-Chip, ein Messelement und einen Drucksensor zur Druckmessungen bei hoher Umgebungstemperatur, besonders über 200 °C, zu beschreiben, wobei die Herstellung eines solchen MEMS-Chips verein- facht werden soll, bei gleichzeitiger Verbesserung der Reproduktion vorgegebener Empfindlichkeiten. The object of the present invention is to describe a MEMS chip, a measuring element and a pressure sensor for pressure measurements at a high ambient temperature, in particular above 200 ° C., whereby the manufacture of such a MEMS chip is simplified. should be at the same time improving the reproduction of given sensitivities.
Gelöst wir diese Aufgabe durch einen MEMS-Chip, ein Messelement und einen Drucksensor gemäss den Merkmalen der Patentan- sprüche 1, 13 und 19. We solve this problem by a MEMS chip, a measuring element and a pressure sensor according to the features of patent claims 1, 13 and 19.
Erfindungsgemäss wird ein eingangs beschriebener MEMS-Chip angegeben, dessen elektromechanische Messmittel derart ausgestaltet sind, indem das MEMS Substrat eine ein Sackloch bildende Kavität aufweist, dessen Rand eine Membran im MEMS Sub- strat ausbildet und eine Messbrücke aus piezoresistiven Elementen auf der der Kavität abgewandten Seite dieser Membran angeordnet ist, wobei das MEMS-Substrat mit der Seite der Kavität dem Trägersubstrat zugewandt auf das Trägersubstrat ge- bondet ist, sodass das Trägersubstrat eine Bodenwand der un- ter der Membrane gebildeten Kavität ausbildet. According to the invention, a MEMS chip described at the outset is provided whose electromechanical measuring means are designed such that the MEMS substrate has a cavity forming a blind hole whose edge forms a membrane in the MEMS substrate and a measuring bridge of piezoresistive elements on the side facing away from the cavity This membrane is arranged, wherein the MEMS substrate is bonded to the side facing the cavity of the carrier substrate on the carrier substrate, so that the carrier substrate forms a bottom wall of the cavity formed below the membrane.
Durch die Grösse, demnach die Fläche des Sacklochs im MEMS- Substrat, der die SOI Schicht bildet, lässt sich somit die Steifigkeit der Membran genau einstellen. Die Dicke der Membrane ist stets identisch, da sich das Sackloch bis zu einer Oxydschicht im MEMS Substrat erstreckt, die als Ätzstopp wirkt . Due to the size, according to which the surface of the blind hole in the MEMS substrate, which forms the SOI layer, the rigidity of the membrane can thus be precisely adjusted. The thickness of the membrane is always identical, since the blind hole extends to an oxide layer in the MEMS substrate, which acts as an etch stop.
Ein weiterer Vorteil besteht darin, dass im Trägersubstrat keine Kavität ausgebildet werden muss. Zudem können die Leitungen an der Oberfläche des MEMS-Substrates angeordnet wer- den, was sich als einfacher erwiesen hat als deren Führung zwischen den beiden Schichten. Another advantage is that no cavity has to be formed in the carrier substrate. In addition, the lines can be arranged on the surface of the MEMS substrate, which has proven to be simpler than their guidance between the two layers.
Solche MEMS Chips lassen sich einfach als Wafer produzieren und in die einzelnen Teile zersägen, was zu Chips mit rechteckigen Querschnitten führt, die einfach zu handhaben sind. Vorteilhafte Ausführungsformen sind in den abhängigen Ansprüchen offenbart. Mittels eines erfindungsgemässen MEMS-Chips kann ein Messelement und daraus ein Drucksensor gebildet werden . Es ergibt sich ein kompakter Aufbau des MEMS-Chips und eines daraus gebildeten Messelementes, wobei als elektromechanische Messmittel eine Membran, eine Kavität abschliessend, verwendet wird. Zur Bestimmung des vorherrschenden Druckes wird die durch die Auslenkung der Membran induzierte mechanische Span- nung verwendet. Die Membran kann sich zu diesem Zweck durchbiegen, da sie an die Kavität angrenzt und nicht aufliegt. Durch die Druckmessung mittels der Membran muss lediglich ein kleiner Teil des MEMS-Chips nach Bildung des Messelementes in einem messenden Bereich frei dem Druckraum und damit dem Me- dium ausgesetzt werden. Die Steifigkeit der Membran wird durch die offene Fläche der Kavität definiert, an die die Membran angrenzt. Such MEMS chips are easy to produce as wafers and saw into the individual parts, resulting in chips with rectangular cross-sections that are easy to handle. Advantageous embodiments are disclosed in the dependent claims. By means of an inventive MEMS chip, a measuring element and from it a pressure sensor can be formed. The result is a compact design of the MEMS chip and a measuring element formed therefrom, wherein a diaphragm, a cavity concluding used as electromechanical measuring means. To determine the prevailing pressure, the mechanical stress induced by the deflection of the membrane is used. The membrane can bend for this purpose because it is adjacent to the cavity and does not rest. Due to the pressure measurement by means of the membrane, only a small part of the MEMS chip after the formation of the measuring element in a measuring range must be exposed to the pressure space and thus to the medium. The stiffness of the membrane is defined by the open area of the cavity adjacent to the membrane.
Die Medientrennung und die Passivierung werden deutlich vereinfacht. Die Medientrennung beim eingebauten Messelement er- folgt im Bereich eines Halterings, der Teil des Messelementes ist . Media separation and passivation are significantly simplified. The media separation in the installed measuring element takes place in the region of a retaining ring, which is part of the measuring element.
Das erfindungsgemässe Messelement ist unter anderem insbesondere für Hochtemperaturdrucksensoren im Automobilbau, in der Luftfahrt, für Gasturbinen, technische Prozesse in der Gas- und Ölförderung, und in der Geothermie einsetzbar. Among other things, the measuring element according to the invention can be used in particular for high-temperature pressure sensors in the automotive industry, in aviation, for gas turbines, technical processes in gas and oil production, and in geothermal energy.
Kurze Beschreibung der Zeichnungen Brief description of the drawings
Ein bevorzugtes Ausführungsbeispiel des Erfindungsgegenstandes wird nachstehend im Zusammenhang mit den anliegenden Zeichnungen beschrieben. Es zeigen Fig. 1 ein erfindungsgemässen MEMS-Chip in einer Aufsicht; A preferred embodiment of the subject invention will be described below in conjunction with the accompanying drawings. Show it 1 shows an inventive MEMS chip in a plan view;
Fig. 2a einen Längsschnitt eines erfindungsgemässen MEMS- Chips mit evakuierter Kavität, geeignet zur Absolutdruckmessung; Fig. 2b einen Längsschnitt eines weiteren erfindungsgemässen MEMS-Chips mit Kanal, geeignet zur Relativ- druckmessung; 2a shows a longitudinal section of an inventive MEMS chip with evacuated cavity, suitable for absolute pressure measurement; 2b shows a longitudinal section of another inventive MEMS chip with channel, suitable for relative pressure measurement;
Fig. 2c einen Längsschnitt eines weiteren erfindungsgemässen MEMS-Chips mit Kanal und weiterer geschlossenen Kavität; FIG. 2c shows a longitudinal section of a further MEMS chip according to the invention with channel and further closed cavity; FIG.
Fig. 3a eine Aufsicht auf ein erfindungsgemässes Messelement mit MEMS-Chip und Haltering; 3a shows a plan view of an inventive measuring element with MEMS chip and retaining ring;
Fig. 3b eine Frontalansicht auf das Messelement gemäss Fig. 3b is a front view of the measuring element according to FIG.
3a vom Kontaktierungsbereich, wie durch den Pfeil in Fig. 3a angedeutet;  3a from the contacting region, as indicated by the arrow in Fig. 3a;
Fig. 3c einen Teilschnitt durch einen erfindungsgemässen Fig. 3c is a partial section through an inventive
Drucksensor, wobei ein Gehäuse das erfindungsgemäs- se Messelement umschliesst und ein Verbindungskabel vom Kontaktierungsbereich aus dem Gehäuse heraus verlegt ist;  A pressure sensor, wherein a housing surrounds the measuring element according to the invention and a connecting cable is laid from the contacting area out of the housing;
Fig. 4a einen Längsschnitt eines erfindungsgemässen Messelementes mit einer Kavität und befestigtem Klemmkontakt ; 4a shows a longitudinal section of an inventive measuring element with a cavity and fixed clamping contact.
Fig. 4b einen Längsschnitt eines erfindungsgemässen Mes- selementes mit an der Kavität anschliessenden Kanal, sowie mit befestigtem Klemmkontakt. Wege zur Ausführung der Erfindung 4b shows a longitudinal section of a measuring element according to the invention with a channel adjoining the cavity and with a fixed clamping contact. Ways to carry out the invention
Ein Teil des hier vorgestellten erfindungsgemässen Messelements zum Messen eines Drucks bei hohen Temperaturen, bevorzugt grösser als 200°C, ist ein MEMS-Chip 3 wie in Figur 1 dargestellt, welcher im Wesentlichen stabförmig ausgebildet ist. Der MEMS-Chip 3 umfasst im. Bereich eines ersten Endes einen messenden Bereich 4 und im Bereich eines zweiten Endes einen Kontaktierungsbereich 6. Im messenden Bereich 4 auf einer längsseitigen Fläche des MEMS-Chips 3 sind elektromecha- nische Messmittel angeordnet. Diese elektromechanischen Messmittel umfassen hier eine Membran 7, welche mit mehreren pie- zoresistiven Elementen 2 dotiert ist, die zu einer Messbrücke 19 ausgebildet sind. Von der Messbrücke 19 sind mehrere Leitungen 8 vom messenden Bereich 4 bis zum Kontaktierungsbe- reich 6 entlang der längsseitigen Fläche des MEMS-Chips 3 verlaufend angeordnet. Die Leitungen 8 münden in eine Mehrzahl von Kontakten 16 im Kontaktierungsbereich 6. Im Benutzungszustand liegt der Kontaktierungsbereich 6 ausserhalb des Druckraumes D, in welchem der Druck bestimmt werden soll. In den Schnittansichten entlang der Längsachse A des MEMS- Chips 3 sind in der Figuren 2 verschiedene Ausführungsformen des MEMS-Chips 3 dargestellt. Alle MEMS-Chips 3 sind jeweils vom einem MEMS-Substrat 30 und einem Trägersubstrat 31 gebildet. Der MEMS-Chip 3 ist hier ein SOI-Si-Chip, der aus dem MEMS-Substrat 30, bevorzugt als SOI-Substrat 30 ausgeführt und dem Trägersubstrat 31 in Form eines Si-Trägersubstrats 31 gebildet ist. Es ist aber ebenfalls möglich, das Trägersubstrat 31 aus Glas, insbesondere aus einem Borosilikatglas herzustellen . Das MEMS-Substrat 30 und das Trägersubstrat 31 sind flächig entlang ihrer Längsachse A aufeinander gebondet angeordnet. A part of the measuring element according to the invention presented here for measuring a pressure at high temperatures, preferably greater than 200 ° C., is a MEMS chip 3 as shown in FIG. 1, which is substantially rod-shaped. The MEMS chip 3 comprises in. Area of a first end of a measuring area 4 and in the region of a second end a contacting region 6. In the measuring region 4 on a longitudinal surface of the MEMS chip 3 electromechanical measuring means are arranged. Here, these electromechanical measuring means comprise a membrane 7, which is doped with a plurality of piezoresistive elements 2, which are formed into a measuring bridge 19. From the measuring bridge 19, a plurality of lines 8 are arranged extending from the measuring region 4 to the contacting region 6 along the longitudinal surface of the MEMS chip 3. The lines 8 open into a plurality of contacts 16 in the contacting region 6. In the use state of the contacting region 6 is outside the pressure chamber D, in which the pressure is to be determined. In the sectional views along the longitudinal axis A of the MEMS chip 3, different embodiments of the MEMS chip 3 are shown in FIGS. All MEMS chips 3 are each formed by a MEMS substrate 30 and a carrier substrate 31. In this case, the MEMS chip 3 is an SOI-Si chip which is made of the MEMS substrate 30, preferably as an SOI substrate 30, and is formed on the carrier substrate 31 in the form of an Si carrier substrate 31. However, it is likewise possible to produce the carrier substrate 31 from glass, in particular from a borosilicate glass. The MEMS substrate 30 and the carrier substrate 31 are arranged in a flat manner along their longitudinal axis A bonded together.
Alle MEMS-Chips 3 weisen eine Kavität 5 im messenden Bereich 4 angeordnet auf, welche aus dem MEMS-Substrat 30 ausgespart bzw. aus diesem herausgeäzt ist. Die Kavität 5, die Membran 7 sowie die . piezoresistiven Elemente 2 sind durch Ätzen, Dotierung und/oder Beschichtung der Substrate 30, 31 hergestellt. All MEMS chips 3 have a cavity 5 arranged in the measuring region 4, which is recessed from the MEMS substrate 30 or etched out of it. The cavity 5, the membrane 7 and the. Piezoresistive elements 2 are produced by etching, doping and / or coating of the substrates 30, 31.
Erfindungsgemäss bildet die Membran 7 die Deckfläche der Kavität 5 und schliesst damit die Kavität 5 druckdicht zur dem Substrat 31 abgewandten Seite ab. Die Membran 7 ist in einer Ebene parallel zur Längsachse A des MEMS-Chips 3 verlaufend angeordnet. Die Bodenwand 50 der Kavität 5 ist von dem Trägersubstrat 31 gebildet. Da beide Substrate 30, 31 aufeinander druckdicht unlösbar verbunden sind, ist die Kavität 5 ge- schlössen. Die Wandstärke der Bodenwand 50 ist um ein Vielfaches grösser als die Dicke der Membran 7. Die Membran 7 mit der Messbrücke 19 ist bevorzugt als eine Dünnfilm-SOI-Membran mit Piezowiderständen 2 ausgebildet. Diese Messbrücke 19 ist ausserhalb der Kavität 5 angeordnet, auf der äusseren Ober- fläche der Membrane 7, dem Substrat 31 abgewandt. According to the invention, the membrane 7 forms the top surface of the cavity 5 and thus closes off the cavity 5 in a pressure-tight manner from the side facing away from the substrate 31. The membrane 7 is arranged to extend in a plane parallel to the longitudinal axis A of the MEMS chip 3. The bottom wall 50 of the cavity 5 is formed by the carrier substrate 31. Since both substrates 30, 31 are connected to each other in a pressure-tight, non-detachable manner, the cavity 5 is closed. The wall thickness of the bottom wall 50 is greater by a multiple than the thickness of the membrane 7. The membrane 7 with the measuring bridge 19 is preferably designed as a thin-film SOI membrane with piezoresistors 2. This measuring bridge 19 is arranged outside the cavity 5, facing away from the substrate 31 on the outer surface of the membrane 7.
Um den Absolutdruck zu messen, ist gemäss des MEMS-Chips 3 der Fig. 2a in der abgeschlossenen Kavität 5 ein Vakuum gebildet. Bei der Produktion des MEMS-Chips 3 wird zu diesem Zweck der Produktionsraum evakuiert und es werden Mittel vor- gesehen, damit das Vakuum in der Kavität langfristig gehalten wird . In order to measure the absolute pressure, according to the MEMS chip 3 of FIG. 2 a, a vacuum is formed in the closed cavity 5. In the production of the MEMS chip 3, the production space is evacuated for this purpose and means are provided for keeping the vacuum in the cavity long-term.
In der Ausführung des MEMS-Chips 3 gemäss Fig . 2b ist die Kavität 5 nicht evakuiert, sondern mit einem Kanal 21 in Richtung Kontaktierungsbereich 6 verlaufend versehen, der durch eine Öffnung 210 zu Atmosphärenbedingungen geöffnet ist. Mit einem solchen MEMS-Chips 3 kann der Relativdruck bzw. Differenzdruck gemessen werden. In the embodiment of the MEMS chip 3 according to FIG. 2b, the cavity 5 is not evacuated, but provided with a channel 21 extending in the direction of the contacting region 6, which is opened through an opening 210 to atmospheric conditions. With Such a MEMS chip 3, the relative pressure or differential pressure can be measured.
In der Ausführung des MEMS-Chips 3 gemäss Figur 2c endet der Kanal 21 in einer weiteren geschlossenen Kavität 12. Diese ist vorzugsweise im Kontaktierungsbereich 6 angeordnet und kann, entgegen der Darstellung, viel grösser ausgestaltet sein als die erste Kavität 5. Da der gesamte vakuumisierte Raum der Kavität 5 in dieser Anordnung viel grösser ist, ist das Vakuum stabiler, selbst wenn Gase vereinzelt in die Kavi- tät 5 hineindiffundieren. Zusätzlich kann in der weiteren Kavität 12 ein Getter 13 angeordnet sein, um das Vakuum möglichst lange zu erhalten. In the embodiment of the MEMS chip 3 according to FIG. 2c, the channel 21 terminates in a further closed cavity 12. This is preferably arranged in the contacting region 6 and, contrary to the illustration, can be made much larger than the first cavity 5. Since the entire vacuumized The space of the cavity 5 is much larger in this arrangement, the vacuum is more stable, even if some gases diffuse into the cavity 5. In addition, a getter 13 can be arranged in the further cavity 12 in order to obtain the vacuum as long as possible.
Der Kanal 21 kann, entgegen der Darstellung in Fig. 2c, ebenfalls im MEMS-Substrat 30 angeordnet sein. Insbesondere kön- nen die weitere Kavität 12 und der Kanal 21 unabhängig voneinander wahlweise im MEMS-Substrat 30 oder im Trägersubstrat 30 angeordnet sein. Zudem besteht die Möglichkeit, den Kanal 21 gemäss Fig. 2b oder 2c auszubilden, indem in diesem Bereich kein Bondmaterial zwischen dem MEMS-Substrat 30 und dem Trägersubstrat 31 vorhanden ist. Somit bildet sich eine Lücke, die als Kanal 21 fungiert, und wahlweise in einer zweiten Kavität 12 oder als Öffnung 210 in die Umgebung endet. The channel 21 can also be arranged in the MEMS substrate 30, contrary to the illustration in FIG. 2 c. In particular, the further cavity 12 and the channel 21 can be arranged independently of one another optionally in the MEMS substrate 30 or in the carrier substrate 30. In addition, it is possible to form the channel 21 according to FIG. 2 b or 2 c in that there is no bonding material between the MEMS substrate 30 and the carrier substrate 31 in this region. Thus, a gap forms, which acts as a channel 21, and optionally ends in a second cavity 12 or as an opening 210 in the environment.
Die Membran 7 ist stets aus dem MEMS-Substrat 30 ausgeformt, wodurch eine offene Kavität 5, ein Sackloch im MEMS-Substrat 30 gebildet ist. Das Sackloch im MEMS-Substrat 30 ist auf der, vom Trägersubstrat 31 abgewandten Seite der Membran 7 vorgesehen und weist vom Trägersubstrat 31 weg. Vorzugsweise ist die das Sackloch bildende Kavität 5 steilwandig, wobei die Wände im Wesentlichen senkrecht zur Membran 7 stehen. Dies hat den Vorteil, dass die Grösse der Kavität 5 genauer reproduziert werden kann und die Kavität 5 insgesamt weniger Platz beansprucht. The membrane 7 is always formed from the MEMS substrate 30, whereby an open cavity 5, a blind hole in the MEMS substrate 30 is formed. The blind hole in the MEMS substrate 30 is provided on the side of the diaphragm 7 facing away from the carrier substrate 31 and points away from the carrier substrate 31. Preferably, the blind hole forming cavity 5 is steep-walled, wherein the walls are substantially perpendicular to the membrane 7. This has the advantage that the size of the cavity 5 is more accurate can be reproduced and the cavity 5 claimed less space overall.
In einer besonders bevorzugten Ausgestaltung wird die Membran 7 zur Kavität 5 hin durch eine Oxydschicht begrenzt. In die- sem Fall dient die Oxydschicht als Ätzstopp, wodurch die Membrane 7 stets in derselben Dicke hergestellt werden kann. In a particularly preferred embodiment, the membrane 7 is limited to the cavity 5 through an oxide layer. In this case, the oxide layer serves as an etch stop, whereby the membrane 7 can always be made in the same thickness.
Auf der der Kavität 5 abgewandten Seite der Membrane 7 ist angrenzend an die Oxydschicht in der Regel eine weitere Siliziumschicht angebracht, welche sich über das gesamte MEMS- Substrat 30 erstreckt. In dieser sind die piezoresistiven Elemente 2 als Widerstände in der Membran 7 ausgestaltet, insbesondere durch Dotierungen im Silizium. Um die Widerstände 2 vom umliegenden Silizium zu isolieren, kann dieses Silizium entweder weggeätzt werden, oder die Widerstände können durch eine Umrandung aus grabenförmigen Oxydschichten vom umliegenden Silizium isoliert werden. On the side of the membrane 7 facing away from the cavity 5, a further silicon layer is generally applied adjacent to the oxide layer and extends over the entire MEMS substrate 30. In this, the piezoresistive elements 2 are designed as resistors in the membrane 7, in particular by doping in silicon. In order to insulate the resistors 2 from the surrounding silicon, this silicon can either be etched away or the resistors can be isolated from the surrounding silicon by a border of trench-shaped oxide layers.
Gemäss den Figuren 2 ist allgemein ersichtlich, dass erfin- dungsgemäss die elektromechanischen Messmittel stets derart ausgestaltet sind, indem das MEMS Substrat 30 eine Kavität 5 aufweist, dessen Boden eine Membran 7 im MEMS Substrat 30 ausbildet, wobei die Messbrücke 19 aus piezoresistiven Elementen 2 auf der der Kavität 5 abgewandten Seite dieser Membran 7 angeordnet ist. Sobald ein Druck auf die Membrane 7 auftritt verbiegt sich diese. Die Widerstände 2 können dieses Durchbiegen durch Änderung der mechanischen Spannung erfassen und entsprechende Signale über die Leitungen 8 zu den Kontakten 16 geben. According to FIGS. 2, it can be generally seen that, according to the invention, the electromechanical measuring means are always designed such that the MEMS substrate 30 has a cavity 5, the bottom of which forms a membrane 7 in the MEMS substrate 30, the measuring bridge 19 consisting of piezoresistive elements 2 the cavity 5 side facing away from this membrane 7 is arranged. As soon as a pressure on the diaphragm 7 occurs, it bends. The resistors 2 can detect this bending by changing the mechanical stress and give corresponding signals via the lines 8 to the contacts 16.
In Figur 3a ist ein erfindungsgemässes Messelement 10 umfassend einen MEMS-Chip 3 mit dem messenden Bereich 4 und dem Kontaktierungsbereich 6 dargestellt, welches hier in einem Haltering 1, der zwischen beiden Bereichen 4,6 platziert ist, angeordnet und unlösbar druckdicht befestigt ist. Der Haltering 1 ist geschlossen ausgeführt und bildet dabei einen Teil der Durchführung des Messelementes 10. Der MEMS-Chip 3 ist in Richtung seiner Längsachse A durch den Haltering 1 geführt, sodass ein Teil des MEMS-Chips 3 innerhalb des Halteringes 1 liegt bzw. von diesem umhüllt ist. Der messende Bereich 4 und der Kontaktierungsbereich 6 ragen in unterschiedlichen Richtungen aus dem Haltering 1 heraus und der Haltering 1 um- schliesst etwa den zentralen Bereich des MEMS-Chips 3. FIG. 3 a shows a measuring element 10 according to the invention, comprising a MEMS chip 3 with the measuring area 4 and the contacting area 6, which here in one embodiment Retaining ring 1, which is placed between the two areas 4,6 arranged and permanently attached pressure-tight. The retaining ring 1 is executed closed and forms part of the implementation of the measuring element 10. The MEMS chip 3 is guided in the direction of its longitudinal axis A through the retaining ring 1, so that a part of the MEMS chip 3 is within the retaining ring 1 or from this is wrapped. The measuring area 4 and the contacting area 6 project out of the retaining ring 1 in different directions, and the retaining ring 1 approximately surrounds the central area of the MEMS chip 3.
Mit Blick auf den Kontaktierungsbereich 6 mit den Kontakten 16 des Messelements 10 in Figur 3b lässt sich der Haltering 1 erkennen, welcher den MEMS-Chip 3 vollständig umgibt. With regard to the contacting region 6 with the contacts 16 of the measuring element 10 in FIG. 3b, the retaining ring 1 can be seen, which completely surrounds the MEMS chip 3.
Ein vollständiger erfindungsgemässer Drucksensor S ist in Fi- gur 3c dargestellt. Dieser umfasst ein Messelement 10 umfassend den MEMS-Chip 3 und den Haltering 1, ein umschliessendes Gehäuse 9 und eine Verkabelung 14. Das Gehäuse 9 erstreckt sich parallel zur Längsachse A des MEMS-Chips 3 und dient zum Schutz des Messelementes 10. Zwischen dem messenden Bereich 4 und dem Kontaktierungsbereich 6 hält der Haltering 1 den MEMS-Chip 3, den er in seinem Umfang umschliesst. Das Messelement 10 ist mit dem Gehäuse 9 unlösbar verbunden, insbesondere ist das Messelement 10 am Haltering 1 mit dem Gehäuse 9 druckdicht verschweisst . Der Haltering 1 und das Gehäuse 9 sind dazu bevorzugt aus Stahl ausgeführt. Das Gehäuse 9 weist in einer Stirnseite mindestens eine Gehäuseöffnung 90 auf, durch welche das Messelement 10 im messenden Bereich 4 mit dem Medium in einem Druckraum D in Kontakt gebracht werden kann. Bevorzugt wird eine Mehrzahl von Gehäuseöffnungen 90 aus der Stirnseitenwand des Gehäuses 9 ausgespart oder die Stirnseitenwand ist als Gitter oder Sieb ausgebildet. - A complete pressure sensor S according to the invention is shown in FIG. 3c. This comprises a measuring element 10 comprising the MEMS chip 3 and the retaining ring 1, a enclosing housing 9 and a wiring 14. The housing 9 extends parallel to the longitudinal axis A of the MEMS chip 3 and serves to protect the measuring element 10. Between the measuring Area 4 and the contacting region 6 holds the retaining ring 1, the MEMS chip 3, which it encloses in its circumference. The measuring element 10 is permanently connected to the housing 9, in particular the measuring element 10 is welded to the retaining ring 1 with the housing 9 pressure-tight. The retaining ring 1 and the housing 9 are preferably made of steel. The housing 9 has, in an end face, at least one housing opening 90, through which the measuring element 10 in the measuring area 4 can be brought into contact with the medium in a pressure space D. Preferably, a plurality of housing openings 90 is recessed from the end wall of the housing 9 or the end wall is formed as a grid or sieve. -
Da nur der messende Bereich 4 des MEMS-Chips 3 dem Medium im Druckraum D ausgesetzt wird, wird nur der entsprechende Abschnitt des Drucksensors S mit dem Druckraum D in Verbindung gebracht. Zur Befestigung des Drucksensors S ist hier ein Aussengewinde 91 vorgesehen, mit welchem der Drucksensor S in eine Wand des Druckraumes D einschraubbar ist. Damit der gesamte Drucksensor S dichtend einschraubbar ist, sind Dichtungsmittel vorgesehen, bevorzugt in Form einer Frontdichtung oder auch hinter dem Gewinde in Form einer Schulterdichtung ausgestaltet. Since only the measuring area 4 of the MEMS chip 3 is exposed to the medium in the pressure space D, only the corresponding portion of the pressure sensor S is brought into communication with the pressure space D. For attachment of the pressure sensor S here an external thread 91 is provided, with which the pressure sensor S in a wall of the pressure chamber D can be screwed. So that the entire pressure sensor S is sealingly screwed, sealing means are provided, preferably configured in the form of a front seal or behind the thread in the form of a shoulder seal.
Eine Verkabelung 14 ist mit den Kontakten 16 am Kontaktie- rungsbereich 6 des Messelementes 10 verkabelt, wobei die Verkabelung 14 einen Teil des Drucksensors S bildet. Durch die Ausbildung des Drucksensors S mit der Verkabelung 14 kann der Drucksensor S direkt, beispielsweise in einem Abgasstrang eines Verbrennungsmotors, verbaut und eine Ausleseelektronik einfach ausserhalb des Druckraumes D und vom messenden Bereich 4 ausreichend störungsfrei beabstandet angeschlossen werden. Je nach Kundenwunsch kann ein Drucksensor S mit ver- kapseltem Messelement 10 und passenden Verbindungsmitteln am Gehäuse 9, beispielsweise in Form eines Aussengewindes 91, vollständig verkabelt und anschlussbereit hergestellt werden. A wiring 14 is wired to the contacts 16 at the contacting area 6 of the measuring element 10, wherein the wiring 14 forms part of the pressure sensor S. Due to the design of the pressure sensor S with the wiring 14, the pressure sensor S directly, for example, in an exhaust system of an internal combustion engine, installed and a readout electronics just outside the pressure chamber D and the measuring area 4 are connected sufficiently trouble-free. Depending on the customer's request, a pressure sensor S with encapsulated measuring element 10 and suitable connecting means on the housing 9, for example in the form of an external thread 91, can be made completely wired and ready for connection.
Zur Veranschaulichung der druckdichten Befestigung des Halteringes 1 am MEMS-Chip 3 dienen die Figuren 4a und 4b. Sie zeigen jeweils einen Längsschnitt durch ein Messelement 10 mit MEMS-Chip 3 und eingeformter Kavität 5, resp. einen Längsschnitt durch ein Messelement 10 mit MEMS-Chip 3, eingeformter Kavität 5 und angrenzenden Kanal 21. Ansonsten sind die Messelemente 10 baugleich ausgeführt. - - To illustrate the pressure-tight attachment of the retaining ring 1 on the MEMS chip 3, FIGS. 4a and 4b are used. They each show a longitudinal section through a measuring element 10 with MEMS chip 3 and molded cavity 5, respectively. a longitudinal section through a measuring element 10 with MEMS chip 3, molded cavity 5 and adjacent channel 21. Otherwise, the measuring elements 10 are of identical design. - -
Wie in Figur 4a erkennbar, ist der MEMS-Chip 3 mit einer Vergussmasse 20 in einem Haltering 1 eingegossen und damit mechanisch stabil gelagert. Die Vergussmasse 20 umgibt den MEMS-Chip 3 entlang des äusseren Umfangs in einem Durchfüh- rungsbereich 11 vollständig und dichtend. Die Vergussmasse 20 verbindet den MEMS-Chip 3 im Durchführungsbereich 11 unlösbar mit dem Haltering 1, wobei die Haltering 1 und die Vergussmasse 20 eine teilweise Verkapselung des MEMS-Chips 3 bilden. Der Durchführungsbereich 11 und damit die Vergussmasse 20 sind zwischen dem messendem Bereich 4 und dem Kontaktierungs- bereich 6 entlang der Längsachse A angeordnet. Der messende Bereich 4 liegt beim Einsatz in einem Druckraum D, der gemessen werden soll, während sich der Kontaktierungsbereich 6 beim Einsatz in einem Umfeld mit ümgebungsdruck befindet. Der Druckraum D ist durch eine Wandung, in den Figuren 4 durch einen grauen Balken dargestellt, vom Umfeld mit Umgebungsdruck getrennt. Der Haltering 1 und die Vergussmasse 20 bilden damit eine druckdichte Durchführung, wobei anstelle befestigter nachteiliger Bondingdrähte hier der gesamte Körper des MEMS-Chips 3 durch den Haltering 1 durchgeführt und mit der Vergussmasse 20 befestigt wird. As can be seen in FIG. 4 a, the MEMS chip 3 is cast in a retaining ring 1 with a potting compound 20 and is therefore mechanically stable. The potting compound 20 surrounds the MEMS chip 3 along the outer circumference in a bushing region 11 completely and sealingly. The potting compound 20 permanently connects the MEMS chip 3 in the feedthrough region 11 to the retaining ring 1, the retaining ring 1 and the potting compound 20 forming a partial encapsulation of the MEMS chip 3. The lead-through region 11 and thus the casting compound 20 are arranged between the measuring region 4 and the contacting region 6 along the longitudinal axis A. The measuring area 4 is in use in a pressure chamber D, which is to be measured, while the contacting area 6 is in use in an environment with ümgebungsdruck. The pressure chamber D is separated by a wall, shown in Figures 4 by a gray bar from the environment with ambient pressure. The retaining ring 1 and the potting compound 20 thus form a pressure-tight passage, wherein instead of attached disadvantageous bonding wires here, the entire body of the MEMS chip 3 is performed by the retaining ring 1 and secured with the potting compound 20.
Der Haltering 1 dient hier zur einfachen Handhabung des Messelementes 10, da das Messelement 10 einfach durch' Kontakt mit dem Haltering 1 in einen Druckraum D einführbar ist, ohne dass auf den messenden Bereich 4 eingewirkt wird. Das Messelement 10 kann direkt druckdicht an der Wand des Druckraumes D befestigt werden. Wenn ein Gehäuse 9, wie in Figur 3c gezeigt, am Haltering 1 befestigt wird, ist eine indirekte Befestigung des Halteringes 1 an der Wand des Druckraumes D über das Gehäuse 9 möglich. Der Haltering 1 ist in den Figuren 4 mit einer Verdickung 100 ausgeführt, welche als Anschlag bei der Befestigung des Gehäuses 9 am Haltering 1 oder der Fixierung des Halteringes 1 direkt an der Wand des Druckraumes D dient. Das Messelement 10 kann einfach und gefahrlos am Haltering 1 gegriffen und in eine Bohrung in der Wand des Druckraumes D eingebracht und dort am Haltering 1 befestigt werden. The retaining ring 1 is used here for easy handling of the measuring element 10, since the measuring element 10 can be inserted simply by ' contact with the retaining ring 1 in a pressure chamber D, without being acted upon the measuring area 4. The measuring element 10 can be attached directly pressure-tight to the wall of the pressure chamber D. If a housing 9, as shown in Figure 3c, attached to the retaining ring 1, an indirect attachment of the retaining ring 1 on the wall of the pressure chamber D via the housing 9 is possible. The retaining ring 1 is executed in the figures 4 with a thickening 100, which serves as a stop in the attachment of the housing 9 on the retaining ring 1 or the fixation of the retaining ring 1 directly to the wall of the pressure chamber D. The measuring element 10 can be easily and safely gripped on the retaining ring 1 and introduced into a hole in the wall of the pressure chamber D and fixed there to the retaining ring 1.
Der Haltering 1 ist hier nur unwesentlich länger in Richtung Längsachse A verlängert ausgestaltet, als der Durchführungs- bereich 11, in dem die Vergussmasse 20 liegt. In weiteren Ausführungsformen kann der Haltering 1 über den Durchführungsbereich 11 deutlich in Richtung des messenden Bereiches 4 verlängert ragen, bzw. den gesamten messenden Bereich 4 überragen, womit der MEMS-Chip 3 zusätzlich geschützt wird. Als Vergussmasse 20 kann eine elektrisch isolierende oder leitfähige Masse mit möglichst kleinem Wärmeausdehnungskoeffizienten, insbesondere Glas, Keramik oder ein Kleber eingesetzt werden. The retaining ring 1 is designed to be only slightly longer in the direction of the longitudinal axis A than the bushing area 11 in which the potting compound 20 is located. In further embodiments, the retaining ring 1 protrude beyond the lead-through region 11 significantly extended in the direction of the measuring region 4, or project beyond the entire measuring region 4, whereby the MEMS chip 3 is additionally protected. As potting compound 20, an electrically insulating or conductive mass with the smallest possible coefficient of thermal expansion, in particular glass, ceramic or an adhesive can be used.
Um den MEMS-Chip 3 im messenden Bereich 4, welcher dem Medium des Druckraumes D bei hohen Temperaturen und hohen Drücken ausgesetzt ist, zu schützen, ist hier eine Passivierungs- schicht 32 angeordnet, insbesondere eine Atomic Layer Deposi- tion-Passivierungsschicht 32. Diese ALD-Passivierungsschicht 32 sollte auf empfindliche Oberflächen aufgebracht werden, die dem je nach Verwendungszweck aggressiven Medium ausgesetzt sind. In order to protect the MEMS chip 3 in the measuring region 4, which is exposed to the medium of the pressure chamber D at high temperatures and high pressures, a passivation layer 32 is arranged here, in particular an atomic layer deposition passivation layer 32 ALD passivation layer 32 should be applied to sensitive surfaces that are exposed to the aggressive medium depending on the intended use.
Da keine empfindlichen Bondingdrähte am Kontaktierungsbereich 6 angeordnet sind, kann hier ein Klemmkontakt 17 einfach und problemlos an der Atmosphärenseite des MEMS-Chips 3 mit den Kontakten 16 kontaktiert werden. Diese Klemmkontakte 17 kön- - Since no sensitive bonding wires are arranged on the contacting region 6, here a clamping contact 17 can be contacted with the contacts 16 simply and easily on the atmosphere side of the MEMS chip 3. These clamping contacts 17 -
nen einfach zu einer Verkabelung führen, die hier nicht dargestellt ist. Just lead to a wiring, which is not shown here.
Während das Messelement 10 gemäss Figur 4a zur Messung des Absolutdruckes benutzt werden kann, kann das bis auf den Ka- nal 21 baugleiche Messelement 10 gemäss Figur 4b zur Differenzdruckmessung genutzt werden. While the measuring element 10 according to FIG. 4 a can be used to measure the absolute pressure, the measuring element 10 of the same design as in FIG. 4 b can be used for differential pressure measurement, except for the channel 21.
Um ein erfindungsgemässes Messelement 10 herzustellen, wird zuerst ein MEMS-Chip 3, umfassend einen Halbleitermaterialverbund aus einem MEMS-Substrat 30 und einem Trägersubstrat 31 hergestellt. Die Kontakte 16, die Leitungen 8, die Messbrücke 19, die piezoresistiven Elemente 2, sowie die Membran 7 sind bei der Substratherstellung bereits anzuordnen und die Halbleitersubstrate 30, 31 aufeinander zu fixieren. Anschliessend wird der MEMS-Chip 3 durch den Haltering 1 in Richtung der Längsachse A geführt und der Haltering 1 mittels Vergussmasse 20 an der Oberfläche des MEMS-Chips 3 vollumfänglich druckdicht fixiert, wobei der Spalt zwischen Oberfläche des MEMS-Chips 3 und Innenfläche des Halteringes 1 komplett ausgefüllt ist, wodurch eine druckdichte Befestigung resultiert. Die Vergussmasse 20 wird dabei im Durchführungsbereich 11 zwischen dem messendem Bereich 4 und dem Kontak- tierungsbereich 6 angeordnet. In order to produce a measuring element 10 according to the invention, a MEMS chip 3 comprising a semiconductor material composite comprising a MEMS substrate 30 and a carrier substrate 31 is first produced. The contacts 16, the lines 8, the measuring bridge 19, the piezoresistive elements 2, as well as the membrane 7 are already to be arranged in the substrate preparation and to fix the semiconductor substrates 30, 31 to each other. Subsequently, the MEMS chip 3 is guided by the retaining ring 1 in the direction of the longitudinal axis A and the retaining ring 1 by means of potting compound 20 on the surface of the MEMS chip 3 fully pressure-tight fixed, the gap between the surface of the MEMS chip 3 and inner surface of the retaining ring 1 is completely filled, resulting in a pressure-tight attachment. The potting compound 20 is arranged in the leadthrough region 11 between the measuring region 4 and the contact area 6.
In den hier beschriebenen Figuren 1, 3a und 3c sind die äusseren Kantenflächen des MEMS-Chips 3 gebrochen ausgeführt dargestellt. Eine derartige optionale Ausgestaltung der äusseren Kantenflächen des MEMS-Chips 3 ist eine Möglichkeit, die Randspannungen, speziell auch im Bereich des Halteringes 1, zu reduzieren. In the figures 1, 3a and 3c described here, the outer edge surfaces of the MEMS chip 3 are shown executed broken. Such an optional embodiment of the outer edge surfaces of the MEMS chip 3 is a possibility to reduce the edge stresses, especially in the region of the retaining ring 1.
Es ist optional möglich, eine Verstärkungselektronik am MEMS- Chip 3 an einer Position im Verlauf des MEMS-Chips 3 entlang - - It is optionally possible to amplify an electronics on the MEMS chip 3 at a position in the course of the MEMS chip 3 along - -
5 Kavität 5 cavity
50 Bodenwand 50 bottom wall
6 Kontaktierungsbereich  6 contacting area
7 Membran  7 membrane
8 Leitung 8 line
9 Gehäuse  9 housing
90 Gehäuseöffnung  90 housing opening
91 Aussengewinde  91 external thread
11 Durchführungsbereich  11 implementation area
12 weitere Kavität 12 more cavities
13 Getter  13 getters
14 Verkabelung/Sensorkabel/äussere elektrische Zuleitung 14 Cabling / sensor cable / external electrical supply
16 Kontakt 16 contact
17 Klemmkontakt  17 clamp contact
19 Messbrücke 19 measuring bridge
20 Vergussmasse  20 potting compound
21 Kanal  21 channel
210 Öffnung 210 opening
A Längsachse  A longitudinal axis
D Druckraum D pressure chamber

Claims

Patentansprüche  claims
1. Micro-Elect ro-Mechanical System Chip (MEMS-Chip) zum 1. Micro-Electro-Mechanical System Chip (MEMS Chip) for
Messen eines Druckes in einem Druckraum (D) , umfassend ein MEMS-Substrat (30) und ein Trägersubstrat (31), die flächig entlang ihrer Längsachse (A) aufeinander gebon- det sind, wobei der MEMS-Chip (3) einen messenden Bereich (4) mit elektromechanischen Messmitteln und einen über Leitungen (8) mit dem messenden Bereich (4) verbundenen Kontaktierungsbereich (6) mit Kontakten (16) auf- weist, wobei der messende Bereich (4) im Betriebszustand dem Druckraum (D) aussetzbar ist und Messsignale von den Kontakten (16) abnehmbar sind, wobei der MEMS-Chip (3) stabförmig ausgestaltet ist und der messende Bereich (4) und der Kontaktierungsbereich (6) in Richtung Längsachse (Ä) durch einen Durchführungsbereich (11) voneinander beabstandet sind, und wobei der MEMS-Chip (3) geeignet ist zur druckdichten Anordnung in einer Durchführung, welche durch ein vollumfängliches Umhüllen der Oberfläche des Durchführungsbereichs (11) normal zur Längsachse (A) ausbildbar ist, dadurch gekennzeichnet, dass die elektromechanischen Messmittel derart ausgestaltet sind, indem das MEMS Substrat (30) eine ein Sackloch bildende Kavität (5) aufweist, dessen Rand eine Membran (7) im MEMS Substrat (30) ausbildet und eine Messbrücke (19) aus piezoresistiven Elementen (2) auf der der Kavität Measuring a pressure in a pressure chamber (D), comprising a MEMS substrate (30) and a carrier substrate (31), which are formed on each other flat along their longitudinal axis (A), wherein the MEMS chip (3) has a measuring area (4) with electromechanical measuring means and via lines (8) with the measuring area (4) connected contacting region (6) with contacts (16) up, wherein the measuring range (4) in the operating state of the pressure chamber (D) can be exposed and measuring signals from the contacts (16) are removable, wherein the MEMS chip (3) is designed rod-shaped and the measuring region (4) and the contacting region (6) in the direction of the longitudinal axis (Ä) are spaced from each other by a lead-through region (11) , and wherein the MEMS chip (3) is suitable for the pressure-tight arrangement in a passage, which can be formed by enveloping the surface of the leadthrough area (11) completely normal to the longitudinal axis (A), characterized in that the electromechanical measuring means are designed such that the MEMS substrate (30) has a cavity (5) forming a blind hole, the edge of which forms a membrane (7) in the MEMS substrate (30) and a measuring bridge (19) of piezoresistive elements ( 2) on the cavity
(5) abgewandten Seite dieser Membran (7) angeordnet ist, und wobei das MEMS-Substrat (30) mit der Seite der Kavität (5) dem Trägersubstrat (31) zugewandt auf das Trägersubstrat (31) gebondet ist, sodass das Trägersubstrat (31) eine Bodenwand (50) der unter der Membrane (7) gebildeten Kavität (5) ausbildet. MEMS-Chip nach Anspruch 1, wobei die Leitungen (8) zwischen dem messenden Bereich (4) und den Kontakten (16) auf der Oberfläche des MEMS-Chips (3) geführt sind. (5) on the opposite side of this membrane (7) is arranged, and wherein the MEMS substrate (30) with the side of the cavity (5) the carrier substrate (31) facing the carrier substrate (31) is bonded, so that the carrier substrate (31 ) forms a bottom wall (50) of the cavity (5) formed below the membrane (7). The MEMS chip of claim 1, wherein the leads (8) are routed between the sensing region (4) and the contacts (16) on the surface of the MEMS chip (3).
MEMS-Chip nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die Dicke der Bodenwand (50) um ein Vielfaches grösser ist als die Dicke der Membran (7). MEMS chip according to claim 1 or 2, characterized in that the thickness of the bottom wall (50) is greater by a multiple than the thickness of the membrane (7).
MEMS-Chip nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass das MEMS-Substrat (30) ein SOI-Substrat (30) und das Trägersubstrat (31) ein Si- Trägersubstrat ist. MEMS chip according to one of the preceding claims, characterized in that the MEMS substrate (30) is an SOI substrate (30) and the carrier substrate (31) is a Si carrier substrate.
MEMS-Chip nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Kavität (5) für Differenzdruckmessungen mit einem Kanal (21) verbunden ist, der sich in den Kontaktierungsbereich (6) erstreckt und dort eine Öffnung (210) aufweist. MEMS chip according to one of the preceding claims, characterized in that the cavity (5) for differential pressure measurements is connected to a channel (21) which extends into the contacting region (6) and has an opening (210) there.
MEMS-Chip nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Kavität (5) mit einem Kanal (21) verbunden ist, der sich in den Kontaktie- rungsbereich (6) erstreckt und dort in einer weiteren geschlossenen Kavität (12) endet. MEMS chip according to one of the preceding claims, characterized in that the cavity (5) is connected to a channel (21) which extends into the contacting region (6) and ends there in a further closed cavity (12).
MEMS-Chip nach Anspruch 6, dadurch gekennzeichnet, dass in der Kavität (12) ein Getter (13) angeordnet ist. MEMS chip according to claim 6, characterized in that a getter (13) is arranged in the cavity (12).
MEMS-Chip nach einem der Ansprüche 5 bis 7, dadurch gekennzeichnet, dass der Kanal (21) gebildet ist, indem in diesem Bereich kein Bondmaterial zwischen dem MEMS- Substrat (30) und dem Trägersubstrat (31) vorhanden ist. MEMS chip according to one of claims 5 to 7, characterized in that the channel (21) is formed by in this area no bonding material between the MEMS substrate (30) and the carrier substrate (31) is present.
9. MEMS-Chip nach einem der vorhergehenden Ansprüche, 9. MEMS chip according to one of the preceding claims,
dadurch gekennzeichnet, dass die das Sackloch bildende Kavität (5) steilwandig ist, wobei die Wände im Wesentlichen senkrecht zur Membran (7) stehen. characterized in that the blind hole forming Cavity (5) is steep-walled, wherein the walls are substantially perpendicular to the membrane (7).
10. MEMS-Chip nach einem der vorhergehenden Ansprüche, 10. MEMS chip according to one of the preceding claims,
dadurch gekennzeichnet, dass die Membran (7) zur Kavität (5) hin durch eine Oxydschicht begrenzt wird.  characterized in that the membrane (7) is limited to the cavity (5) through an oxide layer.
MEMS-Chip nach Anspruch 10, dadurch gekennzeichnet, dass die piezoresistiven Elemente (2) als Widerstände in der Membran (7) angrenzend an die Oxydschicht ausgestaltet sind . MEMS chip according to claim 10, characterized in that the piezoresistive elements (2) are designed as resistors in the membrane (7) adjacent to the oxide layer.
MEMS-Chip nach Anspruch 11, dadurch gekennzeichnet, dass die Widerstände (2) in einer Siliziumschicht, die ausserhalb der Kavität (5) angrenzend an die Oxydschicht angeordnet ist, eingebettet sind, wobei jeweils Oxydschichten die Widerstände (2) von der Siliziumschicht isolieren . MEMS chip according to claim 11, characterized in that the resistors (2) are embedded in a silicon layer, which is arranged outside the cavity (5) adjacent to the oxide layer, wherein respective oxide layers insulate the resistors (2) from the silicon layer.
Messelement umfassend einen MEMS-Chip (3) nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass der MEMS-Chip (3) druckdicht in einer Durchführung angeordnet, welche durch eine den Durchführungsbereich (11) des MEMS-Chips (3) umgebende Vergussmasse (20) und einen die Vergussmasse (20) umschliessenden Haltering (1) gebildet ist. Measuring element comprising a MEMS chip (3) according to one of the preceding claims, characterized in that the MEMS chip (3) arranged pressure-tight in a passage which by a the feedthrough area (11) of the MEMS chip (3) surrounding potting compound ( 20) and a casting compound (20) enclosing the retaining ring (1) is formed.
14. Messelement nach Anspruch 13, dadurch gekennzeichnet, dass die Vergussmasse (20) Glas, Lot oder ein Kleber ist . 14. Measuring element according to claim 13, characterized in that the potting compound (20) is glass, solder or an adhesive.
15. Messelement nach einem der Ansprüche 13 oder 14, dadurch gekennzeichnet, dass der MEMS-Chip (3) im messenden Bereich (4) mit einer Passivierungsschicht (32), bevorzugt mit einer Atomic Layer Deposition-Passivierungsschicht (32) umgeben ist. 15. Measuring element according to one of claims 13 or 14, characterized in that the MEMS chip (3) in the measuring region (4) with a passivation layer (32), preferably surrounded by an atomic layer deposition passivation layer (32).
16. Messelement nach einem der Ansprüche 13 bis 15, dadurch gekennzeichnet, dass der messende Bereich (4) und der Kontaktierungsbereich (6) zu verschiedenen Seiten aus dem Haltering (1) ragen. 16. Measuring element according to one of claims 13 to 15, characterized in that the measuring area (4) and the contacting area (6) to different sides of the retaining ring (1) protrude.
17. Messelement nach einem der Ansprüche 13 bis 16, dadurch gekennzeichnet, dass die Kontakte (16) mit einem Klemmkontakt (17) klemmend einfach verbindbar sind. 17. Measuring element according to one of claims 13 to 16, characterized in that the contacts (16) with a clamping contact (17) are simply connected by clamping.
18. Messelement nach einem der Ansprüche 13 bis 17, dadurch gekennzeichnet, dass sich der Haltering (1) entlang der Längsachse (A) erstreckt und die Vergussmasse (20) in Richtung des messenden Bereichs (4) überragt. 18. Measuring element according to one of claims 13 to 17, characterized in that the retaining ring (1) along the longitudinal axis (A) and extends beyond the potting compound (20) in the direction of the measuring area (4).
19. Drucksensor (S) umfassend ein Messelement (10) gemäss einem der Ansprüche 10 bis 15, dadurch gekennzeichnet, dass ein Gehäuse (9) unlösbar am Haltering (1) des Messelementes (10) druckdicht befestigt, vorzugsweise ange- schweisst ist. 19. Pressure sensor (S) comprising a measuring element (10) according to any one of claims 10 to 15, characterized in that a housing (9) inextricably attached to the retaining ring (1) of the measuring element (10) pressure-tight, preferably welded.
20. Drucksensor (S) gemäss Anspruch 19, dadurch gekennzeichnet, dass ein Aussengewinde (91) am Gehäuse (9) zur Verbindung mit einer Wand eines Druckraumes (D) angeordnet ist . 20. Pressure sensor (S) according to claim 19, characterized in that an external thread (91) on the housing (9) for connection to a wall of a pressure chamber (D) is arranged.
21. Drucksensor (S) nach Anspruch 19 oder 20, dadurch gekennzeichnet, dass sich das Gehäuse (9) über den messenden Bereich (4) erstreckt und die Stirnseitenwand des Gehäuses (9) mindestens eine Gehäuseöffnung (90) aufweist, die offen oder als Gitter oder Sieb ausgestaltet ist . 21. Pressure sensor (S) according to claim 19 or 20, characterized in that the housing (9) extends over the measuring area (4) and the end wall of the housing (9) has at least one housing opening (90) which is open or as Grid or sieve is designed.
EP14789767.2A 2013-10-03 2014-10-02 Mems chip, measuring element and pressure sensor for measuring a pressure Withdrawn EP3052915A1 (en)

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CH01699/13A CH708708A1 (en) 2013-10-03 2013-10-03 Measuring element for measuring a pressure and pressure measuring sensor.
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US20160231189A1 (en) 2016-08-11
CA2924166A1 (en) 2015-04-09

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