• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
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    • 专利摘要:
    The invention relates to a miniaturizable pressure sensor for measuring the pressure of a fluid comprising: a metal membrane intended to be in contact with said fluid and on which are stacked an electrical insulator and at least one measurement gauge of the deformation of said membrane, all forming a sensitive measuring element; a cover comprising: a cap comprising a cavity and holes; o conductors located in said holes, characterized in that said sensor comprises: - at least a first metal zone for hermetically sealing said cover on said sensitive sensing element; second metal zones comprising contact resuming parts with said conductors and parts for resuming contact with said strain gauge (s), the contact resuming parts of the conductors being electrically connected to the contact resumption parts of the or The invention also relates to methods for manufacturing said pressure sensor of the invention.
    公开号:FR3032791A1
    申请号:FR1551368
    申请日:2015-02-18
    公开日:2016-08-19
    发明作者:Fabien Lemery；Stephane Jourdan；David Cayez
    申请人:L'essor Francais Electronique；
    IPC主号:
    专利说明:

    [0001] FIELD OF THE INVENTION The field of the invention is that of "all fluids" compatible pressure sensors and in particular miniaturized pressure sensors for measuring the pressure of a fluid. . GENERAL In general, the pressure of gases and liquids is an important parameter to control in many fields of application such as transport, energy, defense, health or production. This justifies that many pressure sensor technologies have been developed and that research work is still important to improve its performance. The so-called general public markets (automobile, household appliances, altimetry, etc.) are mainly asking for price reductions. The so-called professional markets (aeronautics, production, petroleum exploration, research, etc.) are demanding ever greater precision and resistance to harsh environments, in particular to chemical attacks by all fluids. All areas are demanding more miniaturization. Ideally a pressure sensor should allow to obtain at the same time: - an excellent precision; - good resistance to chemical attack of the environment; - good resistance to temperature; - excellent stability; - a wide frequency response; - a minimum space requirement; - a low cost price. 3032791 2 PRINCIPLE OF MEASUREMENT In most cases, a pressure sensor incorporates a membrane which deforms under the action of a pressure that can typically be exerted by a fluid, this deformation being measured by means of resistive strain gages deposited on the membrane. The gauges change their resistive value by following the deformation of the membrane. Four Wheatstone bridge gages are typically used and positioned so that two gauges increase in value as a result of the deformation and two others decrease. The power supply and the bridge output are connected through contact pins and / or lead wires. These wires are connected to the membrane thanks to connection pads that link to the strain gauges. The sensor generally comprises a so-called upper part called the cover having openings through which contact reversals can pass. Moreover, the sensor can also incorporate a lower part called "tip" for its connection with the client application. Advantageously this nozzle is equipped with a thread (or tapping) and has an opening facing a portion of said membrane on which can be exerted a pressure. The pressure difference between the two faces of the membrane is thus measured. In the particular case where the reference pressure applied to one of the faces is the vacuum, the sensor is said to be absolute. For the so-called relative sensor, one of the faces of the sensitive element is referenced to atmospheric pressure. There are three main families of technology for manufacturing resistance-varying sensors: the so-called silicon-based silicon-membrane technologies, the so-called thin-layer metal-membrane-based technologies and the so-called thick-layer ceramic membrane-based layers.
    [0002] The latter is of interest for cost optimization but significant limitations in terms of fluidic compatibility, miniaturization and also resistance to high pressures and temperatures. The main interest of silicon technologies is that they exploit the resources of miniaturization and cost reduction of microelectronics. Today, they address most of the world's largest public markets. Piezoresistive gauges are either diffused in the membrane (ion implantation of N or P impurities) or monocrystalline silicon on insulator (SOI) for high temperature applications. They give a higher output signal than thin film gauges but their value also varies more with temperature. Their final metrological performance is broadly comparable to thin-film sensors in terms of accuracy. The thin-film technology differs in particular from the two previous ones in that its substrate is metallic. It is therefore naturally compatible with the vast majority of fluids used in the industry. Whatever the fluid, it is in direct contact with the measuring membrane, equipped with strain gauges, without the intermediary of a separating membrane as are equipped with silicon sensors in the presence of corrosive fluids. Thin-film technology sensors also exhibit the characteristics of high strength and accuracy over wide temperature ranges. The signal they deliver is weaker than the silicon sensors but has the advantage of great stability over time. STATE OF THE ART OF "ALL FLUID" SENSORS An important limitation for silicon sensors is the very poor resistance of silicon to corrosive fluids. Manufacturers of pressure sensors that use silicon technology in hostile environments, bypass this problem by shielding the silicon membrane in a stainless metal body. FIG. 1 thus illustrates a sensor of the known art having a silicon membrane. More precisely this sensor comprises: - a connecting piece 1; A silicon membrane 2; a body 3 made of stainless metal enclosing said bonnet membrane for part; intermediate elements 4 in glass-like material with a coefficient of expansion close to silicon, sealed on the base by a flexible material 5; - 6 pins 6 allowing contact resets gauges; an incompressible fluid 7 which transmits the pressure P to the silicon membrane; a flexible wall 8; 5 - wired wiring elements 9. Such a solution works, but significantly reduces the benefits of miniaturization and reduction of expected costs of micro-technologies. Moreover, the flexible and fluid membrane system limits the accuracy, the frequency response and the temperature resistance of the sensor. In addition, these intermediates are weak points and can prohibit their use in specific applications, given the risk of pollution of the process by the fluid 7 of the sensor or instability and inaccuracy if the sensor is subject to variations fast thermal. Another difficulty for silicon sensors is related to the very large coefficient of expansion difference between silicon and metals. In many applications the sensor must be mounted on metal walls by a threaded connection. The silicon chip must therefore be fixed on a metal base, the difference in coefficient of thermal expansion between the two materials then generating parasitic stresses, sources of significant drift. This question is the subject of much attention from manufacturers of silicon sensors that minimize parasitic stress by interposing between the silicon sensor and the metal a material (element 4 shown in Figure 1), generally glass, sufficiently thick (1 to 2mm) and with a coefficient of expansion close to silicon. This material is sealed on the base with a flexible material which thus absorbs a portion of the expansion difference. The use of these intermediate materials can also lead to instability of the measurement over time. Thin film sensor technologies based on metal membranes, stainless steel, titanium, hastelloy, inconel or copper-beryllium, are the oldest and have the advantage of being directly usable with the majority of corrosive fluids. In their case, the measuring diaphragm equipped with the strain gauges is in direct contact with the fluids, without intermediary or protection, as is the case with the incompressible flexible and fluid membrane system for the silicon sensors. Therefore, they are particularly used for applications that require a high resistance to chemical attack, good accuracy and reliability. Their general principle is recalled hereinafter and illustrated in FIG. 2. The pressure membrane 2 is attached to a threaded connection 1. A stack of thin layers, including an electrical insulating layer, the strain gauges 10 and connection pads 16 are deposited by vacuum processes in the vapor phase (chemical or physical) on this metal body. The constituent materials of the gauges in particular can be in thin layers of metal alloys (deposition by cathodic sputtering of NiCr for example) or in semiconductors (polycrystalline silicon deposition for example). The cowling is made with a metal body 3 on which are sealed contact pins 6 by the glass-metal sealing technique, via glass sealing elements 15. The connection of the gages on the pins is performed by a wired wiring 9 achieved by soldering wires 15 conductors. This arrangement allows the creation of the reference pressure cavity 17: empty for the absolute sensors or atmospheric pressure for the relative pressure sensors. A variant of the metal membrane sensor presented above is illustrated in FIG. 3. This variant makes it possible to dispense with a brazing (typically based on tin) carried out directly on the sensitive element. A relay circuit board 18 on which can be made a "bail bonding" wiring 19 (welding of a gold wire by thermo-compression assisted ultrasound) is used in this case. This system is preferable for the temporal stability of the layer but has obvious disadvantages in terms of bulk. The great interest of these sensors is that they are metallic and therefore compatible with most of the aggressive fluids used in the industry. A major obstacle remains to be overcome for these technologies: a very extensive miniaturization to obtain sensors of diameter of the order of 5mm and even less. STATE OF THE ART OF MINIATURE SENSORS On the market, there is mainly a type of miniature metal diaphragm 2 pressure sensor, made in some 35 variants. The metal diaphragm is designed to be flush-welded typically on a threaded miniature metal tip of the M5 type or equivalent as illustrated in FIG. 4, which also highlights the gauge 10 and the insulator I located on said membrane 2. The diaphragm is previously isolated and equipped with silicon bars. For obvious reasons of space, the Wheatstone bridge can be composed of two active gauges ("half bridge" assembly), supplemented by remote fixed resistors. This optimization of the assembly makes it possible to meet the requirements of miniaturization and fluidic compatibility while offering a great dynamic. However, these models do not use thin-film technology and therefore have the disadvantages related to bonded silicon bars, often unacceptable: - the recovery of connections is very complex and impacts reliability; The sensor is sensitive to variations in temperature and in particular to thermal shocks; the process of manufacturing the sensor is essentially manual; the glue used to bring back the silicon bars to the metal membrane induces creep over time and a temperature limitation; In the case of absolute sensor, the vacuum cavity can not be made at the silicon bars, closer to the latter, which limits the possibilities of miniaturization.
    [0003] Silicon membrane technology also offers some miniaturization solutions. Figure 5 depicts a typical state of the art in this field. The silicon chip consists of a silicon-2 membrane with strain gauge gauges made of doped monocrystalline silicon. A glass cover 11 is hermetically sealed by electrostatic bonding ("anodic bonding") to the diffused silicon connection layer 12, thereby protecting the gauges 10 from the outside environment. Openings made in this glass allow this assembly to be electrically connected to contact pins 6 by "fried glass" or "sintered glass" conductor 13 (mixture of gold and sintered glass). Such a solution makes it possible to gain in miniaturization, but it nevertheless always passes through a stack of heterogeneous materials, with complex assembly operations. On the other hand, it does not bring any progress on the resistance to chemical attacks. It is in particular to achieve the dual objective of miniaturization and "all fluids" compatibility that the Applicant has designed a new type of metal membrane sensor which, because of a compact architecture that can be miniaturized, allows: ensure with a few elements a resumption of external contacts measurement gauges; - to be reported easily on any type of mechanical connection. In variants of the invention, the sensor is proposed without wired connection, which adds to the advantages of its thin-film technology, a very strong resistance to vibration, accelerations or shocks. PRESENTATION OF THE INVENTION The solution of the present invention achieves high levels of miniaturization, while retaining the intrinsic advantages of thin film sensors, including compatibility with most fluids and high reliability. Mounting this solution with the membrane flush with the fluid to be measured maximizes miniaturization while providing a response to dynamic measurement requirements. More specifically, the present invention relates to a pressure sensor for measuring the pressure of a fluid comprising: a metal membrane intended to be in contact with said fluid and on which are stacked an electrical insulator and at least one gauge measuring the deformation of said membrane, all forming a sensitive measuring element; a hood comprising: a cap having a cavity and holes; o conductors located in said holes, characterized in that said sensor comprises: - at least a first metal zone for hermetically sealing said cover on said sensitive sensing element; Second metal zones comprising contact-engaging portions of said conductors and contact-return portions of said one or more strain gauges, the contact-return portions of the conductors being electrically connected to the contact-return portions of the gauge or gauges. Conductors are elements that can transmit an electrical signal from one point to another. They may be pins or vias corresponding to holes filled with a material for electrical conduction. According to the present invention, the sensitive element is thus protected by a cover comprising the conductors, said conductors being connected to the strain gauges by electrical connections formed by said second metal zones, the cover being sealed to said sensitive element at the level of a first metal zone. If it is desired to miniaturize the sensor, the space available for sealing the cover on the membrane and the contact elements becomes very small. Indeed, in particular when the conductors are metal pins, inter-pin dimensions, pins themselves and hole holes considerably limit the possibilities of miniaturization. The offset of the pins becomes a particularly interesting solution, because it allows to take advantage of a larger surface of the hood, the sealing cord, more miniature, can remain in the reduced space, initially planned. This is why, according to a variant of the invention, the contact recovery parts of the conductors are offset relative to the contact resumption portions of the strain gauges; the parts of contact recovery of the conductors, always ensuring an electrical connection but having a transmission axis break. According to variants of the invention, the hermetic sealing zone 30 of said cover on the sensitive element is located at the periphery of said sensitive element. According to variants of the invention, the cap is made of metal, the cap and said membrane can be made of the same material. The cap may be stainless steel or titanium or beryllium copper 35 or inconel or Hastelloy.
    [0004] According to variants of the invention, the cap is a ceramic substrate. The cap may also include a stack of ceramic layers having on their surface metal patterns connected between layers by vias. The ceramic material cap has a coefficient of thermal expansion close to that of the metal membrane and can typically be of the order of 10 ppm / ° C. According to variants of the invention, the pins are hermetically fixed to said cap with glass elements. The pins may also be sealed to said cap with at least one metal layer. According to variants of the invention, the parts of resumption of contact with said conductors comprise metallic patterns made in at least one metal layer and covering the end of said pins in the cavity bottom.
    [0005] According to variants of the invention, the parts of resumption of contact with said conductors comprise connection pads connected at the bottom of cavity by wire connection to the end of said pins in the cavity bottom. According to variants of the invention, the hermetic seal is located in a plane perpendicular to the contact resumption plane of said gauges. According to variants of the invention, the cap comprises at least one opening making it possible to reference the element sensitive to the atmospheric pressure or to refer later to the cavity to the vacuum with an additional filling. According to variants of the invention, the sensor comprises a tip. In general, the tip is the mechanical part for both connecting the pressure sensor to the user's connection and to seal it. The user's connection is the mechanical part 30 for a given application, complementary to the tip of the pressure sensor intended to be connected to it. For this purpose, the sensor may comprise a membrane and a tip made of a monolithic metal part. The invention also relates to a method for manufacturing a pressure sensor for measuring the pressure of a fluid according to the invention, characterized in that it comprises: - the production of a sensitive element comprising a membrane made of a first metallic material, an electrical insulator and at least one gauge for measuring the deformation of said membrane; - producing on the surface of said sensing element metal patterns or element capable of forming a eutectic with a metal, to define at least a first sealing member and first contact recovery elements; - The realization of a hood comprising: 10 ^ the realization of a cap of a second material, said cap comprising a cavity, holes, conductors located in said holes: ^ the realization directly on the surface of said hat or the surface of said cavity-side insulated cap, metal patterns, or element capable of forming a eutectic with a metal, so as to define at least a second seal member and second contact-return members; assembling and sealing said sensitive element with said hood so as to form a first metal sealing zone at said sealing elements and second continuous zones comprising contact-return portions of said conductors and a resumption-taking portion of said sealing elements; The subject of the invention is also a method for manufacturing a pressure sensor intended to measure the pressure of a fluid according to the invention, characterized in that it comprises: the embodiment; a sensitive element comprising a membrane 30 made of a first metallic material, an electrical insulator and at least one gauge for measuring the deformation of said membrane; - producing on the surface of said sensitive element metal patterns or element capable of forming a eutectic with a metal, to define first contact recovery elements; Making a cap comprising: producing a cap made of a second material, said cap comprising a cavity, holes, conductors located in said holes: the embodiment directly on the surface of said cap; on the surface of said cavity-covered cap, cavity side, metal patterns or element capable of forming a eutectic with a metal, so as to define second contact recovery elements; Assembling and sealing said sensitive element with said cover in a plane parallel to the contact recovery plane at the sensitive element, so as to form second metal zones for contact recovery; A plane perpendicular to the contact recovery plane at the sensitive element, so as to form a first metal zone hermetically sealing said cover on said sensitive sensing element. According to variants of the invention, the sealing is carried out by brazing, or by welding or gluing. According to variants of the invention, the cap comprising a ceramic substrate, the conductors being pins, the sealing of said pins is made by brazing from a conductive material. According to variants of the invention, the method of manufacturing the sensor comprises the following steps to make the cover: - the production of metallic patterns on the surface of ceramic layers and the production of vias in said layers; the stacking of said layers comprising said patterns and said vias.
    [0006] According to variants of the invention, the metal patterns are made by etching a layer of metal or material capable of forming a eutectic with a metal or by screen printing a metal or a material capable of forming a metal. eutectic with a metal.
    [0007] LIST OF FIGURES The invention will be better understood and other advantages will become apparent on reading the following description, which is given in a nonlimiting manner and by virtue of the appended figures in which: FIG. 1 illustrates a first example of pressure sensor known as "all fluids" according to the known art comprising a silicon membrane and a separating membrane; FIG. 2 illustrates a second example of an "all fluids" pressure sensor according to the known art comprising a metal membrane; FIG. 3 illustrates a third example of a so-called "all fluids" pressure sensor according to the known art comprising a metal membrane; FIG. 4 illustrates a first example of a miniature pressure sensor according to the known art comprising a metal membrane; FIG. 5 illustrates a second example of a miniature pressure sensor according to the known art comprising a silicon membrane; FIGS. 6a to 6f show sectional views and perspective views of a first type of pressure sensor according to the invention comprising conductors facing contacting resumptions of the strain gauges; FIG. 7 represents an assembly operation of a cover and a sensitive element constituting a step of a method of manufacturing a sensor according to the invention; FIG. 8a shows a sectional view of the sensing element in a second type of sensor of the invention comprising remote conductive elements with respect to the resumption of contact of the strain gauges; FIG. 8b represents a view from above of the sensitive element in the second type of sensor of the invention; Figure 9a shows a sectional view of the hood in the second type of sensor of the invention; FIG. 9b represents a view from below of the cover integrated in the second type of sensor of the invention; - Figure 10 shows a sectional view of the second type of pressure sensor of the invention; FIGS. 11a to 11d show exploded perspective views of the sensitive element part and the cover of the second type of sensor according to the invention; FIG. 12a represents a third type of sensor according to the invention; Figure 12b shows a view from below of the hood incorporated in the third type of sensor according to the invention; FIGS. 13a to 13c show a sectional view and perspective views of a fourth type of sensor according to the invention, in which the sealing operation is carried out in a plane perpendicular to the contact recovery plane at the level of the sensitive element; FIG. 14 represents a sectional view of a fifth type of sensor of the invention incorporating a hood made in the LTCC technique; - Figure 15 shows a sectional view of a sensor according to the invention equipped with an attachment; FIG. 16 represents a sectional view of a sensor according to the invention comprising a monolithic piece incorporating the membrane and a bit; - Figures 17a and 17b show a sectional view and a perspective view of a sensor according to the invention equipped with an attached tip.
    [0008] DETAILED DESCRIPTION OF THE INVENTION In general, the pressure sensor of the present invention comprises a sensing element with a membrane equipped with at least one measuring gage for measuring the deformation of said membrane, under the action of a pressure of interest.
    [0009] The sensor comprises at least a first metal zone making it possible to hermetically fasten a cover intended to ensure the protection of said membrane and referencing to a reference pressure, the first metal zone being located at the interface between 5 the sensing element and the hood. The sensitive element comprises a part of the second metal areas of contact recovery of the strain gauge or gauges. The cover consists of a cap having holes in which conductors are positioned. The leads can typically be pins or vias. The cover also includes part of the second metal areas of contact recovery conductors. Such a configuration makes it possible to develop sensors of small dimensions, requiring a limited number of elements. Advantageously, the sensor may comprise a ceramic cap (made of alumina, for example) with a coefficient of expansion close to that of the metal of the membrane. The advantage of this solution is to have an insulating material that avoids the deposition of an insulating thin layer, a potential source of electrical faults. When the leads are metal pins (typically Kovar) and the cap is made in a ceramic substrate, the method of sealing the pins at the cap may be a conventional brazing process based on the Mo-Mn metallization processes generally in the form of of powders. These are deposited on the ceramic to be metallized then the whole is baked at high temperature. To improve the adhesion and the wettability of the solder, an alloy is deposited in thin or thick layers. The most used are silver-based alloys (AgCu, AgCuPd, ...), copper or gold-based alloys (Au).
    [0010] A metal that is often etched on alumina is Kovar (Fe-28Ni18Co alloy), which can therefore be an excellent material for contact pins. Other alloys such as Mo-Mn (so-called "active" alloys) can also be used.
    [0011] The first type of pressure sensor according to the invention: According to this first alternative embodiment of a pressure sensor, and illustrated in FIGS. 6a, 6b, 6c and 6d, the sensitive element comprises a membrane 20 equipped with measurement gauges. on the surface of an insulating layer 20 '. Conventionally, the sensor can be equipped with a set of four Wheatstone bridge mounted gauges and positioned so that, under the effect of deformation, two gauges increase in value and two others decrease. According to this example, the conductors are pins. Thus, the power supply and the output of the bridge can be connected to the outside of the sensor (making the signals available / accessible to the outside) by means of contact pins 60 previously fixed hermetically by fixing elements 150 to a sensor. hat 30 and located in holes. The pressure sensor comprises a first metal zone Z1, making it possible to hermetically fasten said cover on said sensitive measuring element and second metal zones for taking up contacts Z2 of said pins and connected to said strain gauge or gauges. . Conductive patterns are defined in a conductive layer 21, and in a conductive layer 31, as illustrated in all of Figures 6a-6d. The stack of these conductive patterns made in the layers 21/31 makes it possible to locally define: the first zone Z1 resulting from the stacking of the zones Z1.21 and Z1-31 coming from the layers 21 and 31, respectively, to ensure the fixation the sensing element and hood; the second zones Z2 resulting from the stacking of the zones Z2.21 and Z2-31 coming from the layers respectively 21 and 31 to ensure the resumption of contact of the gages via the pins 60. According to this variant of the invention, the pins are located next to the second areas Z2-21 of contact resumption and therefore the contact resuming portions with said conductors are opposite the contact recovery portions of said strain gauges, as shown in Figure 6b. In order to simultaneously carry out the zones Z1 and Z2, the pressure sensor can advantageously be assembled by assembling the sensitive membrane 20 and the cover 30 comprising pins 60 inserted into the holes in a single operation, hermetic sealing 3032 791 16 and the contact between the gauges 100 and the pins 60 being obtained at the same time by reflow (eutectic sealing) of a stack of metal layers 21 + 31 in which are defined the metallic patterns. FIGS. 6c and 6d show the realization of metallic patterns 5 making it possible to define, at the level of the sensitive element, the zones Z1.21 and Z2-21 respectively dedicated to the sealing and to the resumption of contact of the gauges 100 and to the level of the cover zones Z1.31 and Z2-31 respectively dedicated to the sealing and resumption of contact of the pins 60. FIG. 6e shows a variant with a hole T making it possible to produce a so-called relative sensor, having the atmospheric pressure as the reference pressure. . Figure 6f shows a variant with the addition of a cap B to seal the vacuum later. Preferably, the cap and the membrane are of materials having the closest possible expansion coefficients, most preferably identical. In this case, an insulating thin layer, typically SiO 2 or Al 2 O 3, is deposited first on the active faces of the metal, this being not shown in FIGS. 6a and 6b. To achieve the assembly of the sensitive element and the cover, it is possible to carry out a brazing operation. In order to provide an optimum hermetic bond, the process of the present invention may advantageously comprise a eutectic metal sealing operation. More precisely, the sealing operation can, according to an advantageous embodiment, be carried out with the stack of layers illustrated in FIG. 7 with thicknesses of metal layers of the order of 25 micrometers (μm). The part of the cap 30 comprises an Au layer, the sensing element comprises stacked on the membrane 20, an insulating layer, a layer in which the gauges are made, an Au layer, a Si layer and a layer of Au, sealing being an eutectic seal.
    [0012] The metal sealing zone may thus advantageously consist of a eutectic layer such as Au / Si. Other elements may also be used to form eutectics such as Au / Sn, Al / Ge, etc. The composition is chosen according to the best possible compromise between sealing temperature, sealing, bulk, strength, reproducibility. From this point of view a preferred solution may be the Au / Si composition. Eutectic sealing is obtained by contacting, then heat treatment at a temperature above the melting temperature of the alloy of gold and silicon layers. Thus a cover comprising a gold layer and a sensitive element 5 covered with a stack: Au / Si / Au can be fixed together with a sealing temperature greater than 363 ° C. Second type of pressure sensor according to the invention: According to this variant of the invention, which is particularly advantageous for miniaturization, as illustrated in FIGS. 8a, 8b, 9a, 9b and 10, the sensitive element part may be the same as in the previously described variant. A part 20 comprises a membrane part, comprising on the surface at least one strain gauge 100 (or preferably four gates Wheatstone bridge mounted). The production of metallic patterns makes it possible to define, at the level of the sensitive element, the zones Z1.21 and Z2-21 respectively dedicated to the sealing and to the resumption of contact of the gauges 100 as shown in FIGS. 8a and 8b. According to this variant of the invention, the output pins 60 are located in a central and hollow portion of the cap. FIGS. 9a and 9b thus illustrate the cap 30 equipped with contact recovery pins 60, and the zones Z1.31 and Z2-31 respectively dedicated to sealing and resuming contacts of the pins 60, positioned in through holes 63. The assembly operation may be identical to that developed in the previous variant. FIG. 10 illustrates the sensor and its cavity 32 after assembly of the parts 20 and 30. The bringing into contact of the zones Z1-21 and Z1.31 coming from the layers respectively 21 and 31 makes it possible to define the zone Z1 to ensure the fixing of the sensitive element and hood. Contacting the zones Z2.21 and Z2-31 from the layers 21 and 31, respectively, makes it possible to define the zone Z2 and to ensure the resumption of contact of the gauges 30 via the pins 60. This figure shows the offset of the pins 60 and Z2-31 contact pick-up areas with respect to the Z2-21 contact pick-up areas. The advantage of this variant is that the width of the sealing bead, corresponding to the zone Z1 can be reduced independently of the diameter of the output pins, pins which can not be miniaturized to the extreme. Thanks to this solution it becomes possible to go very far in miniaturization. FIGS. 11a and 11b illustrate perspective views of this variant of the invention, respectively highlighting on the one hand Z1.21 and Z2-21 zones defining metallic patterns that may result from the etching of the metal layer. 21 made on the surface of the sensitive element and secondly, the pins 60 coated at their end of the metallization layer 31, referenced 60+ 31, to ensure the definition of the zones Z2-31. The end of the pins 60 may also emerge from the bottom of the hat cavity holes (FIG. 11b), be aligned with the cavity bottom (FIG. 11c), or still be located inside the holes. emerging from the hat (Figure 11d), the layer 31 nonetheless infiltrate the through holes and also coat their end to ensure a resumption of contact.
    [0013] Third type of pressure sensor according to the invention According to this variant of the invention, the pressure sensor integrates a wired wire of the "lease bonding" or "wedge bonding" type between contact pins and metallic patterns belonging to the parts of the invention. resumption of contact of the conductors. FIGS. 12a and 12b illustrate this variant highlighting the wired wiring 19 making it possible to connect the end of the pins 60 to the metal layer 31. Fourth type of pressure sensor according to the invention: According to this other variant of the invention , the mechanical attachment of the cover on the metal membrane is provided by any means of welding, soldering or gluing. The contact is always ensured by reflow. According to this variant illustrated in FIGS. 13a, 13b and 13c, the sealing is carried out in a zone Z1 ', for example by gluing, at an interface located in a plane P' perpendicular to the plane P of contact recovery at the level of the sensitive element. Advantageously, and according to a variant, the part in which the cap is made is structured to allow after assembly a rotation alignment of the faces of the parts 20 and 30.
    [0014] A fifth type of pressure sensor according to the invention: An alternative to the cap comprising a ceramic substrate may be to use a stack of ceramic layers. For this purpose, Low Temperature Co-fired Ceramics (LTCC) techniques can be used to provide the hood with integrated conductors. FIG. 14 illustrates an example of a cover comprising a stack of dielectric layers 30a, 30b on the surface of which metal patterns 60b_a are made interconnected by metal vias 60a, 60b. The circuit is then made from flexible sheets of ceramics (30a and 30b). These sheets are then cut out, pierced with vias and the metallic patterns screen printed with conductive ink. The manufacture of the hood is then finalized by cooking the stack in an oven. In general, the sensor of the present invention is a compact and miniaturizable pressure sensor, easily connectable with customer connectors. To ensure this connection function, the sensor comprises a tip. First example of a pressure sensor according to the invention 20 comprising a nozzle intended to cooperate with a customer connector: According to this example, the metal part 20 is secured to a tip 40 itself having a threaded portion as shown in FIG. ensure a tight fitting with a customer connection.
    [0015] Second example of a pressure sensor according to the invention comprising a nozzle intended to cooperate with a customer connector: According to this example, the membrane 20 and the nozzle are made in a monolithic metal part, the tip portion itself having a portion threaded as shown in FIG. 16, to provide a tight fitting with a customer connection. Third example of a pressure sensor according to the invention comprising a nozzle intended to cooperate with a customer connector: The mounting of a solution with the membrane flush with the fluid to be measured makes it possible to optimize the miniaturization while offering a response to the requirements of dynamic measures. According to this example, the metal part 20 is secured to a tip 40 itself having a threaded portion as shown in Figures 17a and 17b, to ensure a tight connection with a customer connection.
    权利要求:
    Claims (23)
    [0001]
    REVENDICATIONS1. Pressure sensor for measuring the pressure of a fluid comprising - a metal membrane intended to be in contact with said fluid and on which are stacked an electrical insulator and at least one gauge for measuring the deformation of said membrane, all of which forming a sensitive sensing element; a cover comprising: a cap comprising a cavity and holes; o conductors located in said holes, characterized in that said sensor comprises: - at least a first metal zone for hermetically sealing said cover on said sensitive sensing element; second metal zones comprising contact resuming portions of said conductors and contact resuming portions of said one or more strain gauges, the contact resuming portions of the conductors being electrically connected to the contact resumption portions of the one or more gauges.
    [0002]
    2. A pressure sensor for measuring the pressure of a fluid according to claim 1, characterized in that the contact-engaging portions of said conductors are offset relative to the contact-return portions of said strain gauges, providing an electrical connection. having a transmission axis break.
    [0003]
    3. Pressure sensor for measuring the pressure of a fluid according to one of claims 1 or 2, characterized in that the hermetic sealing zone of said cover on the sensitive element is located at the periphery of said sensitive element. 3032791 22
    [0004]
    4. Pressure sensor for measuring the pressure of a fluid according to one of claims 1 to 3, characterized in that said cap is metal. 5
    [0005]
    5. Pressure sensor for measuring the pressure of a fluid according to claim 4, characterized in that said cap and said membrane are made of the same material.
    [0006]
    6. Pressure sensor for measuring the pressure of a fluid 10 according to one of claims 1 to 3, characterized in that said cap is made of ceramic material.
    [0007]
    Pressure sensor for measuring the pressure of a fluid according to claim 6, characterized in that the conductors are vias
    [0008]
    8. Pressure sensor for measuring the pressure of a fluid according to one of claims 6 or 7, characterized in that the cap comprises a stack of dielectric layers having on their surface metal patterns connected between layers by vias .
    [0009]
    9. Pressure sensor for measuring the pressure of a fluid according to one of claims 1 to 6, characterized in that said conductors are pins. 25
    [0010]
    10. The pressure sensor for measuring the pressure of a fluid according to claim 9, characterized in that said pins are hermetically fixed to said cap with glass elements.
    [0011]
    11. A pressure sensor for measuring the pressure of a fluid according to claim 9, characterized in that said pins are hermetically fixed to said cap with at least one metal layer.
    [0012]
    Pressure sensor for measuring the pressure of a fluid according to one of claims 1 to 6 and 9 to 11, characterized in that the contact-engaging portions of said conductors comprise metallic patterns made in at least one metal layer covering the end of said conductors at the bottom of the cavity. 15 20 3032791 23
    [0013]
    13. Pressure sensor for measuring the pressure of a fluid according to one of claims 1 to 6 and 9 to 11, characterized in that the contact recovery portions of said conductors comprise connection pads connected to the bottom of the cavity by wired connection to the end of said 5 pins in the cavity bottom.
    [0014]
    14. Pressure sensor for measuring the pressure of a fluid according to one of claims 1 to 13, characterized in that the hermetic seal is located in a plane perpendicular to the contact recovery plane of said gauges.
    [0015]
    15. Pressure sensor for measuring the pressure of a fluid according to one of claims 1 to 14, characterized in that the cover comprises at least one opening for referencing the element 15 sensitive to atmospheric pressure.
    [0016]
    16. Pressure sensor for measuring the pressure of a fluid according to one of claims 1 to 15, characterized in that it comprises a tip on which is reported said sensitive element. 20
    [0017]
    17. Pressure sensor for measuring the pressure of a fluid according to one of claims 1 to 15, characterized in that it comprises a monolithic piece comprising said sensitive element and a tip. 25
    [0018]
    18. A method of manufacturing a pressure sensor for measuring the pressure of a fluid according to one of claims 1 to 13 and 15 to 17, characterized it comprises: - the realization of a sensitive element comprising a membrane made of a first metallic material, an electrical insulator and at least one gauge for measuring the deformation of said membrane; - producing on the surface of said sensitive element metal patterns or element capable of forming a eutectic with a metal, to define at least a first sealing member and first contact recovery elements; - The realization of a cap comprising: 3032791 24 ^ the realization of a cap of a second material, said cap comprising a cavity, through holes, conductors located in said holes: ^ the realization directly on the surface of said cap or At the surface of said cavity-side insulated cap, metal patterns or element capable of forming a eutectic with a metal, so as to define at least a second seal member and second contact-return members; ; - assembling and sealing said sensing element with said cover so as to form a first metal sealing area at said sealing members and second continuous metal areas having contact engaging portions of said leads and a portion of 15 contact resumption of said one or more strain gauges.
    [0019]
    19. A method of manufacturing a pressure sensor for measuring the pressure of a fluid according to claim 14, characterized in that it comprises:
    [0020]
    The production of a sensitive element comprising a membrane made of a first metallic material, an electrical insulator and at least one gauge for measuring the deformation of said membrane; - producing on the surface of said sensitive element patterns of metal or element capable of forming a eutectic with a metal, to define first contact recovery elements; the production of a cap comprising: the production of a cap made of a second material, said cap comprising a cavity, holes, conductors located in said through holes: the embodiment directly on the surface of said cap or the surface of said cavity-side insulated cap of metal patterns or element capable of forming a eutectic with a metal, so as to define second contact resumption elements; - assembling and sealing said sensitive element with said cover in: a plane parallel to the contact recovery plane at the sensing element, so as to form 5 seconds metal contact recovery zones; a plane perpendicular to the contact recovery plane at the sensitive element, so as to form a first metal zone hermetically sealing said cover on said sensitive sensing element. 20. A method of manufacturing a pressure sensor for measuring the pressure of a fluid according to one of claims 18 or 19, characterized in that the seal is made by brazing, or by welding or gluing.
    [0021]
    21. A method of manufacturing a pressure sensor for measuring the pressure of a fluid according to one of claims 18 to 20, characterized in that the cap comprises a ceramic substrate, the conductors being pins, the sealing of said pins is made by soldering.
    [0022]
    22. A method of manufacturing a pressure sensor for measuring the pressure of a fluid according to one of claims 18 to 20, characterized it comprises the following steps to achieve the hood: - the realization of patterns metal on the surface of ceramic layers and making vias in said layers; the stacking of said layers comprising said patterns and said vias. 30
    [0023]
    23. A method of manufacturing a pressure sensor for measuring the pressure of a fluid according to one of claims 18 to 22, characterized in that the metal patterns are made by etching a layer of metal or material capable of forming a eutectic with a metal or by screen printing of a metal or material capable of forming a eutectic with a metal.
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    同族专利:
    公开号 | 公开日
    FR3032791B1|2018-09-07|
    US20160238477A1|2016-08-18|
    US10060812B2|2018-08-28|
    引用文献:
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    JP5752852B2|2011-06-07|2015-07-22|ジャワハルラール ネール センター フォー アドバンスド サイエンティフィク リサーチ|Manufacture strain sensing sensors and / or strain resistant conduits from metals and carbon matrix|JP6340734B2|2015-09-18|2018-06-13|Smc株式会社|Pressure sensor|
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    法律状态:
    2016-01-25| PLFP| Fee payment|Year of fee payment: 2 |
    2016-08-19| PLSC| Publication of the preliminary search report|Effective date: 20160819 |
    2017-01-26| PLFP| Fee payment|Year of fee payment: 3 |
    2018-01-29| PLFP| Fee payment|Year of fee payment: 4 |
    2020-01-27| PLFP| Fee payment|Year of fee payment: 6 |
    2021-01-26| PLFP| Fee payment|Year of fee payment: 7 |
    2022-02-10| PLFP| Fee payment|Year of fee payment: 8 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1551368A|FR3032791B1|2015-02-18|2015-02-18|MINIATURE METAL MEMBRANE PRESSURE SENSOR AND METHOD FOR MANUFACTURING THE SAME|
    FR1551368|2015-02-18|FR1551368A| FR3032791B1|2015-02-18|2015-02-18|MINIATURE METAL MEMBRANE PRESSURE SENSOR AND METHOD FOR MANUFACTURING THE SAME|
    US15/046,244| US10060812B2|2015-02-18|2016-02-17|Miniature pressure sensor having a metallic membrane for measuring a pressure of a fluid|
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