The invention relates to an electromechanical microsystem comprising an electromechanical transducer, a deformable membrane and a cavity hermetically containing a deformable medium, preserving a constant volume under the action of an external pressure change. The deformable membrane forms a wall of the cavity and has at least one free zone being deformed. The electromechanical transducer is configured, such that its movement is a function of said external pressure change, and conversely. The free zone engages with an external member, such that its deformation induces, or is induced by, a movement of the external member. The electromechanical microsystem is thus capable of moving the external member or of capturing a movement of this member.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the field of electromechanical microsystems. It has, for example, a particularly advantageous application in the actuation or the movement of objects, including over relatively large distances. The invention also has an application in the field of contact detection. It can thus be implemented to produce sensors.

STATE OF THE ART

In varied applications, there can be a need to move microscopic, even nanoscopic objects, and/or a need to capture movements of such objects. There are microsystems which enable this.

When these microsystems are actuators, their performances are evaluated in particular on the following parameters: the amplitude of the movement, the force used and the accuracy of the movement generated. When these microsystems are sensors, their performances are evaluated in particular on the following parameters: the capacity to capture a movement over a significant amplitude.

Moreover, whether the microsystems are actuators or sensors, it is sought that they offer good performances in terms of bulk, energy consumption and capacity to work in frequency.

All the known solutions have low performances for at least one of these parameters. Generally, the current microsystems have performances which are insufficiently satisfactory for a combination of these parameters.

An aim of the present invention is to propose an electromechanical microsystem which has improved performances with respect to the current solutions, at least for one of the parameters mentioned above, or which has a better compromise relating to at least two of the abovementioned parameters.

Other aims, features and advantages of the present invention will appear upon examining the following description and the accompanying drawings. It is understood that other advantages can be incorporated.

SUMMARY OF THE INVENTION

To achieve this aim, according to an embodiment, an electromechanical microsystem is provided, comprising:a. at least one electromechanical transducer comprising a part which is moveable between a non-urged balanced position, and an urged non-balanced position,b. at least one deformable membrane,c. a deformable cavity delimited by walls.

At least one part of the deformable membrane forms at least one part of a first wall taken from among said walls of the cavity.

The cavity is configured to hermetically contain a deformable medium specific to preserving a substantially constant volume under the action of an external pressure change exerted on the deformable medium through one of the walls of the cavity.

The moveable part of the electromechanical transducer is configured such that its movement is a function of said external pressure change or conversely that its movement induces an external pressure change.

Said at least one part of the deformable membrane has at least one free zone to be deformed according to said external pressure change.

The electromechanical microsystem is further such that said at least free zone is configured to engage with an external member such that its deformation induces, or is induced by, a movement of the external member.

Furthermore, a surface of the free zone of the deformable membrane is twice less than a surface of the moveable part of the electromechanical transducer.

The electromechanical microsystem such as introduced above is thus capable of moving the external member or of capturing a movement of this member, and this, by having, in an easily adjustable manner according to the targeted applications, a sufficient capacity in terms of movement amplitude and/or a sufficient capacity in terms of force used and/or a movement capturing capacity over a sufficient amplitude and/or a sufficient capacity to work in frequency and/or a size compatible with the targeted applications, and/or a reduced energy consumption.

Moreover, the solution proposed makes it possible for the electromechanical microsystem to form a so-called long-travel actuator, i.e. typically enabling the movement of the external member over a stroke length of at least 30 μm, even 100 μm. Likewise, a solution proposed makes it possible for the electromechanical microsystem to form a so-called long-travel sensor, typically enabling to capture a movement, the amplitude of which is at least 30 μm, even 100 μm.

Optionally, the free zone of the deformable membrane is configured to engage with the external member via a finger, also called pin, fixed on said free zone. Preferably, the pin is fixed in contact with said free zone, and more specifically in contact with an external face of the free zone. Even more preferably, the pin is formed at the same time as the free zone of the deformable membrane is exposed. According to the latter preference, it is advantageously simpler to obtain the pin, and any risk of tearing the deformable membrane is thus avoided, contrary to a case wherein the pin would be deposited, and more specifically mounted, on the deformable membrane.

Another aspect of the invention relates to an opto-electromechanical system or microsystem comprising at least one electromechanical microsystem such as introduced above and at least one optical microsystem.

Another aspect of the invention relates to a method for manufacturing an electromechanical microsystem such as introduced above, comprising, even limited to, ordinary microelectronic deposition and etching steps. The electromechanical microsystem can indeed be manufactured by ordinary microelectronic means, which gives to its manufacturer all the advantages arising from the use of these means, including a large latitude in terms of sizing, adhesion energy between the different depositions, thickness of different depositions, etching extent, etc.

According to an example, the method for manufacturing the electromechanical microsystem comprises the following steps:a. a step of forming, on a substrate, a portion at least of at least one electromechanical transducer, thenb. a step of depositing the deformable membrane, thenc. a step of forming an open cavity on the deformable membrane, thend. a step of filling with the deformable material and of closing the cavity, ande. a step of etching the substrate to form a front face (FAV) of the electromechanical microsystem.

The drawings are given as examples, and are not limiting of the invention. They constitute principle schematic representations intended to facilitate the understanding of the invention and are not necessarily to the scale of practical applications. In particular, the thicknesses of the different layers, walls and members illustrated are not necessarily representative of reality. Likewise, the lateral dimensions of the piezoelectric element, of the free zone of the membrane and/or of the abutments are not necessarily representative of reality, in particular when considered against one another.

DETAILED DESCRIPTION OF THE INVENTION

Before starting a detailed review of embodiments of the invention, optional features are stated below, which can optionally be used in association or alternatively.

According to an example, the free zone is free to be elastically deformed according to said external pressure change.

The electromechanical microsystem such as introduced above, preferably has no optical element, such as a lens, in particular with a variable focal length.

When the free zone of the deformable membrane is configured to engage with the external member via a pin, the latter can have the following optional features which can optionally be used in association or alternatively.

According to an example, the pin is fixed at the centre of the free zone of the deformable membrane. In this way, it is ensured that the movement of the pin is a translation movement perpendicular to the plane wherein the wall of the cavity falls, which is partially formed by the deformable membrane, when the membrane is not deformed.

According to an example, the pin extends mainly in a longitudinal direction. When the membrane is not deformed, the longitudinal direction of the pin is substantially perpendicular to a plane (xy), wherein an external face of the membrane mainly extends when the membrane is not deformed. The pin can have a cylindrical shape. According to an alternative embodiment, the pin does not have a cylindrical shape. It can have a curved shape, for example.

According to an example, the pin has a first end by which it bears on the free zone and a second end opposite the first end.

According to an example, the pin extends between the first end and the second end, mainly in a longitudinal direction. Alternatively, the pin has a curved shape or extends in several different directions.

According to an example, the free zone has a central portion extending from a centre of the free zone and a peripheral portion disposed around the central portion. For example, the pin bears by its first end on the central portion of the free zone.

The pin can be configured to engage with the external member by way of an integral guide of the external member, so as to enable an automatic positioning of the external member on the pin.

According to an example, the pin is configured to be able to be integral with the external member by bonding or magnetism.

According to an example, the adherence energy of the pin on the free zone of the deformable membrane is greater than that of the pin on the external member.

Thanks to the pin according to either of the two preceding examples, a securing, optionally removable, of the pin and of the external member is provided, which is widely adjustable in terms of retaining force.

According to an example, at least one part of the electromechanical transducer forms a part of the wall of the cavity which is partially formed by the deformable membrane. The electromechanical microsystem according to this feature has a non-through structure, leaving the other walls of the cavity free, so as to be able to carry out other functions there or so as to enable them to remain inert, for an increased integration capacity, in particular in an opto-electromechanical microsystem.

According to an example, the electromechanical transducer extends, directly over the deformable membrane, i.e. that the electromechanical transducer is directly in contact with the deformable membrane. Alternatively, the electromechanical transducer extends indirectly over the deformable membrane, i.e. that at least one element or one intermediate layer is disposed between the electromechanical transducer and the deformable membrane.

According to an example, the electromechanical transducer fully surrounds the free zone of the deformable membrane.

According to a non-limiting example, the electromechanical transducer takes an annular shape, the circular centre of which defines the extent of the free zone of the deformable membrane.

The electromechanical transducer can be configured such that a movement of its moveable part from its balanced position to its unbalanced position induces an increase of the external pressure acting on the deformable medium and the deformable membrane can be configured such that an increase of external pressure acting on the deformable medium induces a deformation of the free zone of the deformable membrane tending to move the external member of the cavity away (more specifically, to move it away from the fixed wall of the cavity such as the wall opposite the wall partially formed by the membrane). The electromechanical microsystem is thus configured so as to induce a movement of the external member in a first direction, corresponding to a moving away of the external member with respect to the cavity.

Alternatively to the preceding feature, the electromechanical transducer can be configured such that a movement of its moveable part from its balanced position to its unbalanced position induces a decrease of the external pressure acting on the deformable medium and the deformable membrane can be configured such that a decrease of the external pressure acting on the deformable medium induces a deformation of the free zone of the deformable membrane tending to move the external member of the cavity closer (more specifically, to move it closer to a fixed wall of the cavity such as the wall opposite the wall partially formed by the membrane). The electromechanical microsystem is thus configured so as to induce a movement of the external member in a second direction, this second direction tending to move the external member of the cavity closer.

At least the moveable part of the electromechanical transducer can be integral with a zone of the deformable membrane adjacent to the free zone of the deformable membrane, such that a movement of the moveable part of the electromechanical transducer, including a movement inducing the moving closer of the external member with respect to the cavity, induces a corresponding movement of said zone of the deformable membrane adjacent to its free zone.

The electromechanical microsystem such as introduced above can further comprise a plurality of deformable membranes and/or a plurality of free zones per deformable membrane and/or a plurality of electromechanical transducers.

The moveable part of the electromechanical transducer can have a surface at least twice greater than a surface of the free zone of the deformable membrane. Preferably, the surface of the moveable parts of the transducers is at least 5 times, even 10 times, even 20 times greater than the surface of the free zone121of the deformable membrane, even than the surface of the free zones of the deformable membrane. The larger the surface of the transducer is with respect to the surface of the free zone121of the deformable membrane, even to the surface of the free zones of the deformable membrane, the greater the deformation amplitude will be.

The deformable membrane is preferably configured such that its free zone is capable of being deformed with an amplitude of at least 50 μm, even of at least 100 μm, even of at least 1000 μm, in a direction perpendicular to the plane wherein it mainly extends, when it is at rest. Without tearing and/or without significant wear, the electromechanical microsystem thus offers the capacity to satisfy numerous and various applications requiring a long travel, the latter being defined, if necessary, by technical field in question.

The electromechanical microsystem can further comprise at least one lateral abutment configured to guide the movement of the external member and/or to engage a non-moveable part of an electromechanical transducer. According to an optional example, the lateral abutment is supported by the wall of the cavity which is partially formed by the deformable membrane. According to an optional example, said at least one lateral abutment extends opposite the cavity.

It is thus possible to:a. limit, in a controlled, reliable and reproducible manner, the inclination of the pin during the movement of the moveable part of the electromechanical transducer, and/orb. enable a self-positioning of the external member relative to the free zone of the deformable membrane, and/orc. protect the deformable membrane, and more specifically, its free zone, in particular, a possible tearing, during a transfer or a bonding of the external member.

When the free zone of the deformable membrane is configured to engage with the external member via a pin fixed on said free zone, the electromechanical microsystem can further have the following optional features which can optionally be used in association or alternatively.

The pin can extend from the free zone of the deformable membrane beyond said at least one lateral abutment.

Alternatively, the pin can extend from the free zone of the deformable membrane below said at least one lateral abutment.

The electromechanical microsystem according to either of the two preceding features offers a satisfactory adaptation capacity to a wide variety of external members and applications.

The electromechanical microsystem can further comprise a so-called bottom abutment supported by the wall of the cavity opposite the free zone of the deformable membrane, said bottom abutment extending into the cavity towards the free zone. It has a shape and dimensions configured to limit the deformation of the free zone of the deformable membrane so as to protect the deformable membrane, and more specifically its free zone, in particular, a possible tearing, during a transfer or a bonding of the external member. Moreover, the so-called bottom abutment can be shaped to limit the contact surface between the membrane and the wall of the cavity opposite the free zone of the deformable membrane. Alternatively or cumulatively, the bottom abutment can be shaped so as to limit the contact surface between the membrane and the wall of the cavity opposite the free zone of the deformable membrane. This makes it possible to avoid the membrane adhering to this wall.

The electromechanical transducer can be a piezoelectric transducer, preferably comprising a PZT-based piezoelectric material.

The electromechanical transducer can be a static working transducer.

Alternatively or complementarily, the electromechanical transducer can be a vibration working transducer at at least one resonance frequency, said at least one resonance frequency preferably being less than 100 kHz, and also more preferably less than 1 kHz.

The deformable medium hermetically container in the cavity can comprise at least one fluid, preferably liquid. The fluid preferably has a viscosity of around 100cSt at ambient temperature and pressure (1cSt=10−6m2/s).

According to a non-limiting example of an embodiment, the fluid has a compressibility of between 10−9and 10−10Pa−1at 20° C., for example of around 10−10Pa−1at 20° C., without these values being limiting.

Said at least one optical microsystem of the opto-electromechanical system such as introduced above can comprise at least one mirror, also called micro-mirror, preferably silicon-based.

According to an example, the opto-electromechanical system is configured such that the movement of the moveable part of the electromechanical transducer causes a movement of the at least one mirror.

Alternatively or complementarily, the opto-electromechanical system can comprise a plurality of electromechanical microsystems, each having a free zone arranged opposite a part of one same optical microsystem, such as a mirror. Preferably, the electromechanical microsystem engages with the mirror at a zone which is not at the centre of the mirror, but for example, in the corner of the mirror. An opto-electromechanical system or microsystem is thus obtained, benefiting from a wide adaptation capacity of its optical orientation.

By “electromechanical microsystem”, this means a system comprising at least one mechanical element and at least one electromechanical transducer made on a micrometric scale with microelectronic means. The mechanical element can be moved (actuated) thanks to a force generated by the electromechanical transducer. The latter can be supplied by electrical voltages produced with neighbouring electronic circuits. Alternatively or complementarily, the electromechanical transducer can capture a movement of the mechanical element; the electromechanical microsystem thus plays the role of a sensor.

A “microsystem” is a system, the external dimensions of which are less than 1 centimetre (10−2metres) and preferably than 1 millimetre (10−3metres).

Most often, an electromechanical transducer plays a role of an interface between the mechanical and electrical fields. However, in this case, by “electromechanical transducer”, this means both a piezoelectric transducer and a thermal transducer, the latter playing a role of an interface between the mechanical and thermal fields. An electromechanical transducer can comprise a moveable part between a non-urged balanced position, and an urged unbalanced position. When the transducer is piezoelectric, the urging is of an electrical nature. When the transducer is thermal, the urging is of a thermal nature.

When the centre of the cavity is mentioned, this centre is defined geometrically by considering as the centre of a cavity having a non-deformed free zone of the deformable membrane.

By “less than” and “greater than”, this means “less than or equal to” and “greater than or equal to”, respectively. Equality is excluded by using the terms “strictly less than” and “strictly greater than”.

By a parameter “substantially equal to/greater than/less than” a given value, this means that this parameter is equal to/greater than/less than the given value, plus or minus 20%, even 10%, of this value. By a parameter “substantially between” two given values, this means that this parameter is, as a minimum, equal to the smallest given value, plus or minus 20%, even 10%, of this value, and, as a maximum, equal to the largest given value, plus or minus 20%, even 10%, of this value.

FIGS.1A and1Bare principle diagrams of a cross-sectional view or of a cross-section of an electromechanical microsystem1according to the first and second embodiments of the invention. In each of theFIGS.1A and1B, an electromechanical transducer11, a deformable membrane12and a cavity13are illustrated, configured to hermetically contain a deformable medium14.

Each of these principle diagrams can also represent a symmetrical structure of rotation or revolution about a perpendicular axis and centred with respect to the cross-section of the deformable membrane such as illustrated, that a structure extending, for example in a substantially invariant manner, perpendicular to the cross-sectional view illustrated and symmetrically with respect to a plane perpendicular and centred with respect to the cross-section of the deformable membrane such as illustrated.

Before describing the different embodiments of the invention illustrated in the accompanying figures further, it is noted that each of these illustrations schematically represent an embodiment of the electromechanical microsystem according to the invention, which has a non-through structure. More specifically, in the different embodiments illustrated, the electromechanical transducer11and the deformable membrane12are both located on the front face FAV of the electromechanical microsystem1. This type of structure is particularly advantageous insofar as the rear face FAR of the electromechanical microsystem1can only passively contribute, and in particular without being deformed, to the actuator and/or sensor function of the electromechanical microsystem1. More specifically, the rear face FAR of an electromechanical microsystem1with non-through structure according to the invention can, in particular, constitute a face by which the electromechanical microsystem1can be easily mounted on a support (referenced32inFIGS.11A and11B) and/or can constitute a face by which the electromechanical microsystem can easily be further functionalised.

However, the invention is not limited to non-through structure electromechanical microsystems. In its widest acceptance, the invention also relates to so-called through structure electromechanical microsystems1, wherein the electromechanical transducer11and the deformable membrane12are arranged on walls which are distinct from one another from the cavity13, that these walls are adjacent to one another or opposite one another.

The electromechanical transducer11comprises at least one moveable part111. The latter is configured to move or be moved between at least two positions. A first of these positions is a balanced position, reached and preserved when the electromechanical transducer11is not urged, whether, for example, by an electrical current supplying it or by a force stressing its moveable part outside of its balanced position. A second position of the moveable part111of the electromechanical transducer11is reached when the electromechanical transducer11is urged, whether, for example, by electrical current supplying it or by a force stressing its moveable part outside of its balanced position. The electromechanical transducer11can be held in either of the first and second positions described above, and thus have a binary behaviour, or can further be held in any intermediate position between its balanced position and its position of greatest deformation, or of greatest deflection, with respect to the balance.

In the example illustrated, when the electromechanical transducer11is not urged, its moveable part111mainly extends into a plane parallel to the plane xy of the orthogonal system xyz illustrated inFIG.1A.

The electromechanical transducer11is preferably a piezoelectric transducer. More specifically, the electromechanical transducer11comprises at least one piezoelectric material mechanically coupled with another element, qualified as a support or beam. The term of “beam” does not limit at all the shape of this element.

In a known manner, a piezoelectric material has, as a property, of stressing when an electric field is applied to it. By being stressed, it is deformed. Mechanically associated to the support, the piezoelectric material drives the support with it and thus moves the latter. The zone of the support which can be moved corresponds to the moveable part111. It is this movement property which is used to form an actuator.

Likewise, under the action of a mechanical stress, a piezoelectric material is electrically polarised. Thus, when the support is moved, it deforms the piezoelectric material which induces an electrical current. It is this property which is used to form a sensor.

It therefore emerges from this example of an embodiment of the electromechanical transducer11, but this remains potentially true for each of the other embodiments considered of the electromechanical transducer11, that the electromechanical microsystem1according to the invention can operate as actuator and/or sensor. As an actuator, it can make it possible to move an external member2upwards, as illustrated inFIG.1A, or downwards, as illustrated inFIG.1B. As a sensor, it can make it possible to capture a movement, in particular a vertical movement, of the external member2. Below, for reasons of simplicity, the electromechanical microsystem1is mainly described as an actuator, without however excluding its capacity to ensure, alternatively or complementarily, a sensor function.

The electromechanical transducer11is even more preferably a piezoelectric transducer comprising a PZT-based piezoelectric material (lead zirconate titanate). In this case, the moveable part111of the electromechanical transducer11is capable under urging of moving with a more significant movement (due to the piezoelectric coefficient d31) than with a good number of other piezoelectric materials. However, PZT being a ferroelectric material, such a piezoelectric transducer operates preferably in one single actuation direction (movement in one single direction of its moveable part111), whatever the polarity of its electrical supply, while a piezoelectric transducer with the basis of a non-ferromagnetic material can preferably operate in both directions (movement in two opposite directions of its moveable part111). Alternatively or complementarily, the electromechanical transducer11can be a (non-ferroelectric) piezoelectric transducer with the basis of a material specific to enabling its moveable part111to move in opposite directions relative to its balanced position, for example, according to the polarity of its electrical supply. Such a material is, for example, an aluminium nitride (AlN)-based material.

Alternatively or complementarily, the electromechanical transducer11can be or comprise a thermal transducer.

The deformable membrane12can be with the basis of a polymer, and is preferably PDMS(polydimethylsiloxane)-based. The properties of the deformable membrane12, in particular its thickness, its surface and its shape, can be configured to give to the deformable membrane12, and more specifically to a zone121of this membrane, which is free to be deformed, an expected tearing capacity, in particular, according to the targeted application.

The cavity13such as illustrated, in particular, inFIGS.1A and1Bhas more specifically, walls131,132,133hermetically containing the deformable medium14. In the examples illustrated, the wall132of the cavity13constitutes the rear face FAR of the electromechanical microsystem1. The wall131opposite the wall132is formed at least partially by at least one part of the deformable membrane12. Thus, the wall131is deformable. The wall131is referenced below as first wall. It is located at the front face FAV of the electromechanical microsystem1. At least one side wall133joins together the walls131and132. It will be noted that the hermeticity of the cavity13can require that the deformable membrane12is itself impermeable, or made impermeable, in particular at its free zone121.

It will also be noted that, to ensure the hermeticity of the cavity13more easily:a. the first wall131of the cavity is preferably fully formed or covered by at least the deformable membrane12, and/orb. the electromechanical transducer11extends from its whole extent over the deformable membrane12, by being in direct or indirect contact with it.

Preferably, the walls132,133remain fixed when the membrane12is deformed.

The deformable medium14is itself specific to preserving a substantially constant volume under the action of an external pressure change. In other words, this can be an incompressible or slightly compressible medium, the deformation of which preferably requires little energy. This is, for example, a liquid.

Due to at least one part of the wall131of the cavity13is formed by at least one part of the deformable membrane12, it is understood that any external pressure change exerted on the deformable medium14can be compensated for by a deformation, substantially proportional, of the deformable membrane12, and more specifically of its free zone121, and/or by a movement of the moveable part111of the electromechanical transducer11. When the transducer is urged, this compensation is more specifically linked to a conversion of the external pressure change exerted on the deformable medium14in a tearing of the deformable membrane12or a relaxation of the deformable membrane12already torn. It is reminded that the deformable medium14is incompressible and that these stresses are therefore carried out with a preservation of the volume of the cavity13. It is understood that, being concerned about reproducibility of the actuation or of the capturing of the movement that the electromechanical microsystem1according to the invention offers, it is preferable that any deformation of the deformable membrane12is elastic, and not plastic, to guarantee the return into the same state of lesser tearing, or of maximum relaxation, of the deformable membrane12each time that it is no longer stressed.

The deformable medium14can more specifically comprise at least one fluid, preferably liquid. The parameters of the liquid will be adapted according to the targeted applications. It is thus ensured that any external pressure change exerted on the deformable medium14induces a substantially proportional deformation of the free zone121of the deformable membrane12. The fluid can be constituted, or with the basis, of a liquid, such as oil or can be constituted, or with the basis, of a polymer. According to an example, the fluid is glycerine-based, or is constituted of glycerine. It is thus ensured that, in addition to a substantially proportional deformation of the membrane12, of the capacity of the deformable medium14to occupy, in particular, the volume created by tearing of the free zone121of the deformable membrane12opposite the centre of the cavity13.

It is understood from the above, that the electromechanical microsystem1is configured, such that the movement of the electromechanical transducer1is a function of the external pressure change exerted on the deformable medium14, to perform the function of an actuator of the electromechanical microsystem1, and conversely, to perform the function of a sensor of the electromechanical microsystem1. More specifically, when the electromechanical microsystem1plays the role of an actuator, the electromechanical transducer11is urged so as to exert an external pressure change on the deformable medium14and through that, induce the deformation of the deformable membrane12. Conversely, when the electromechanical microsystem1plays the role of a sensor, the deformation of the membrane12exerts an external pressure change on the deformable medium14which induces a movement of the moveable part111of the electromechanical transducer11.

As illustrated in each ofFIGS.1A and1B, the electromechanical microsystem1is such that the free zone121of the deformable membrane12is configured to engage with an external member2. In this way, the deformation of the free zone121induces, or is induced by, a movement of the external member2. It is therefore by way of the free zone121of the deformable membrane12that the electromechanical microsystem1moves the external member2or captures a movement of the external member2. Thus, when the electromechanical microsystem1plays the role of an actuator, the activation of the electromechanical transducer11deforms the membrane12which moves the member2. Conversely, when the electromechanical microsystem1plays the role of a sensor, a bearing of an external member2on the membrane12or a traction of the membrane12by an external member2deforms the membrane12, which moves the electromechanical transducer11then ultimately generates a signal. Such that the signal generated can be a function of the movement of the external member2, and in particular, of its movement amplitude, it is preferable that the surface of the free zone121is greater than the surface of the moveable part111of the electromechanical transducer11, which is in contact with the deformable membrane12.

More specifically, the engagement between the free zone121of the deformable membrane12and the external member2can be achieved via a finger, also called pin122, which is fixed on the free zone121. The terms “finger” and “pin” can be switched. The term “pin” is not limited to the parts of constant cross-section and a fortiori to the cylindrical parts.

As illustrated in each of theFIGS.1A and1B, the pin122can be more specifically fixed to the centre of the free zone121of the deformable membrane12, or more generally, symmetrically with respect to the extent of the free zone121of the deformable membrane12. In this way, the pin122is moved, by the elastic deformation of the free zone121, in a substantially vertical controlled direction, and is not or is slightly inclined with respect to the vertical during its movements. The lateral travel of the pin122is thus advantageously limited.

Complementarily or alternatively, the external member2can be structured so as to comprise a guide by which the external member2is intended to engage with the pin122. This guide can itself also contribute to opposing an inclination of the pin122during its movement. It will be seen below that the limitations thus reached in terms of lateral travel of the pin122can also be reinforced by the presence of at least one lateral abutment15extending from a part of the wall131located outside of the free zone121of the deformable membrane12.

In a non-limiting manner, a bonding or a magnetising of the pin122on the external member2can make it possible to secure the pin122and the external member2together. The adherence energy of the pin122on the free zone121of the deformable membrane12is preferably greater than that of the pin122on the external member2. It will be seen, when the methods for manufacturing the electromechanical microsystems1illustrated inFIGS.2A and2Bwill be described, that the adherence energy of the pin122on the free zone121can be a result from ordinary technological steps in the microelectronics field. This adherence energy could thus be estimated or measured, it is easy to obtain by bonding, for example using an ad hoc resin, or by magnetising, for example a securing, which is of an energy lower than the energy with which the pin122is integral with the deformable membrane12. It is therefore understood that the securing between the pin122and the external member2is thus widely adjustable in terms of retaining force. This adjustability can make it possible, in particular, to make the securing between the pin122and the external member2removable, for example to enable one same electromechanical microsystem1according to the invention to be arranged successively with several external members2, each with which it would be secured, then disconnected.

As illustrated in each ofFIGS.1A and1B, the electromechanical transducer11can form a part of the first wall131of the cavity13. The electromechanical transducer11and the deformable membrane12are thus placed on one side of the cavity13. The structures having this feature are advantageously non-through as stated above.

In this non-limiting example, the membrane12has an internal face12iconfigured to be in contact with the deformable medium14and an external face12e. The internal face12iforms a part of the first wall131of the cavity13. Preferably, to easily ensure the hermeticity of the cavity13, the internal face12iof the membrane12forms the whole first wall131of the cavity13. The electromechanical transducer11, more specifically the moveable part111of the latter, has an internal face11irotated facing, and preferably in contact with the external face12eof the membrane12. The electromechanical transducer11also has an external face11e, opposite the internal face11i, and rotated towards the outside of the electromechanical microsystem1. Preferably, to easily ensure the hermeticity of the cavity13, the internal face11iof the electromechanical transducer11is preferably fully in contact with the external face12eof the membrane12. It can be provided that one or more intermediate layers are disposed between the external face12eof the membrane12and the internal face11iof the electromechanical transducer. The electromechanical microsystem1is configured such that the movement of the moveable part111of the electromechanical transducer11causes a movement of the membrane12and therefore of the wall131which confines the medium14.

It will be noted that, in each ofFIGS.1A and1B:a. the electromechanical transducer11extends over the deformable membrane12by defining the free zone121of the deformable membrane12, andb. the deformable membrane12separates the electromechanical transducer11, preferably over its whole extent, from the deformable medium14.

Furthermore, the electromechanical transducer11can advantageously be integral with the deformable membrane12on a zone123located outside of the free zone121, and more specifically, on a zone123adjacent to the free zone121, such that any movement of the moveable part111of the electromechanical transducer11induces, in particular on this zone123, a tearing of the deformable membrane12. Thus, in the example illustrated inFIG.1B, when the electromechanical transducer11is urged so as to be moved upwards (as illustrated by the two arrows extending from the moveable part111of the electromechanical transducer11), a decrease of the external pressure exerted on the deformable medium14is observed, which induces the tearing of the deformable membrane12downwards, i.e. towards the centre of the cavity13. In this case, it is noted that this securing between the electromechanical transducer11and the deformable membrane12is only preferential for the electromechanical microsystem1represented inFIG.1A, insofar as the moveable part111of the electromechanical transducer11is intended to bear on the deformable membrane12when the electromechanical transducer11is urged and/or insofar as the deformable membrane12naturally tends to remain in contact with the moveable part111of the electromechanical transducer11when the latter does not bear on the deformable membrane12.

FIG.1Cillustrates the partial covering of the deformable membrane12by the electromechanical transducer11. The electromechanical transducer11takes its shape from a ring of radial extent referenced R2and defines a circular free zone121of radius referenced R1. It is noted that the electromechanical transducer11is not limited to an annular shape, but can take other shapes, and in particular, an oblong or oval shape, a triangular, rectangular shape, etc., defining a corresponding plurality of shapes of the free zone121of the deformable membrane12. This illustration applies, in particular, to a symmetrical structure of rotation or of revolution. However, a corresponding illustration for a symmetrical structure with respect to a plane perpendicular and centred with respect to the cross-section of the free zone121could, at the same time, be supplied which would in particular consist of the representation of three adjacent strips two-by-two, the central strip of which would represent the free zone121of the deformable membrane12, and the lateral strips of which would represent the moveable part of the electromechanical transducer(s)11involved.

In particular, when the partial covering of the deformable membrane12by the electromechanical transducer11is such as illustrated inFIG.1Cand that the electromechanical transducer11is a piezoelectric transducer comprising a PZT-based piezoelectric material, it is interesting that the moveable part111of the electromechanical transducer11has a surface at least twice larger than the free zone121of the deformable membrane12. The deformable membrane12is subsequently configured such that its free zone121is capable of being deformed with an amplitude of at least 50 μm, around 100 μm, even several hundred μm. Preferably, the surface of the moveable part111of the electromechanical transducer11illustrated inFIG.1Cis at least 5 times, even 10 times, even 20 times larger than the surface of the free zone121of the deformable membrane12illustrated in the same figure. The measurements indicated above as an example correspond to a surface of the moveable part111of the electromechanical transducer11, nineteen times larger than the surface of the free zone121of the deformable membrane12.

Generally, the deformable membrane12is preferably configured, such that its free zone121is capable of being deformed with an amplitude of less than 1 mm.

The deformation amplitude of the free zone121is measured in a direction perpendicular to the plane, wherein the external face12eof the membrane12mainly extends at rest.

Without tearing and/or without significant wear, the electromechanical microsystem1enables a hydraulic amplification of the actuation and thus offers the capacity to satisfy numerous and various applications requiring a long travel. In this context, the electromechanical microsystem1illustrated inFIG.1Acan be defined as an ascending long-travel actuator and the electromechanical microsystem1illustrated inFIG.1Bcan be defined as a descending long-travel actuator.

Also, when the partial covering of the deformable membrane12by the electromechanical transducer11is such as illustrated inFIG.1Cand that the electromechanical transducer11is a piezoelectric transducer comprising a PZT-based piezoelectric transducer, but in reference toFIGS.2A and2Bdiscussed in more detail below, the electromechanical transducer11can more specifically comprise a support305, also called beam305, and a PZT-based piezoelectric element302, the latter being configured to induce a deflection of the support305. The term “beam”305does not limit the shape of the support305. In this example, the beam305forms a ring. The thickness of the piezoelectric element302can be substantially equal to 0.5 μm and the thickness of the beam305is, for example, of between a few μm and several tens of μm, for example, 5 μm.

Always, when the partial covering of the deformable membrane12by the electromechanical transducer11is such as illustrated inFIG.1Cand that the electromechanical transducer11is a piezoelectric transducer comprising a PZT-based piezoelectric material, the radius R1of the free zone121of the deformable membrane12can be substantially equal to 100 μm and the radial extent R2of the electromechanical transducer11(typically, its radius if it is circular) can be substantially equal to 350 μm. The references R1and R2are illustrated inFIG.1C. In such a configuration, the moveable part111of the electromechanical transducer11can be moved or deflected with an amplitude, for example, substantially equal to 15 μm by being crossed by an electrical voltage, for example, substantially equal to 10V for a beam305thickness of around 5 μm and a PZT thickness of around 1 μm.

It must be noted that, in its balanced position, the moveable part111of the electromechanical transducer11, and more generally, the electromechanical transducer11, cannot be flat, but can, on the contrary, have a deflection, called balanced, which removes nothing, in terms of amplitude, movement capacity or deflection of the electromechanical transducer11electrically supplied.

The invention is not however limited to the different specific values given above, which can be widely adapted, according to the targeted application, in particular to find a compromise between tearing factor and expected deformation amplitude of the free zone121of the deformable membrane12.

It is noted that, in particular when the electromechanical transducer11is a piezoelectric transducer, the electromechanical transducer11can advantageously be a vibration working transducer. Its resonance frequency is thus preferably less than 100 kHz, and even more preferably, less than 1 kHz. The vibration dynamic thus obtained can make it possible to reach greater travels than in static working, in particular by utilising the phenomenon of pertaining resonance or of decreasing the consumption of the electromechanical microsystem for a given travel.

As already mentioned above, the electromechanical microsystem1can further comprise one or more lateral abutments15supported by the first wall131of the cavity13. Each lateral abutment15extends more specifically to the opposite of the cavity13. For example, each lateral abutment15extends from a non-moveable part of the electromechanical transducer11.

Each lateral abutment15can further have an action of holding in position a non-moveable part of the electromechanical transducer11, said non-moveable part being complementary to the moveable part111of the electromechanical transducer11.

Opposite at least one part of the or of each lateral abutment15relative to the deformable membrane12, at least one spacer306, such as schematically illustrated inFIGS.1A and1B, can extend into the cavity13or by constituting a part of the side wall133of the cavity13. Such a spacer306makes it possible to sandwich, together with the abutment or each lateral abutment15, the non-moveable part of the electromechanical transducer11, for example on at least one part of its outer perimeter, so as to reinforce the holding in position of this non-moveable part.

For example, as illustrated inFIGS.2A and2B, the action of holding the non-moveable part of the electromechanical transducer11can more specifically be ensured by its engagement between the two lateral abutments15, and in particular, that located towards a central part of the microsystem1, and the spacer306, such as illustrated inFIGS.2A and2B, which materialises the side wall133of the cavity13; in this sense, the spacer306preferably extends towards the central part of the microsystem1at least up to the right of the surface of the lateral abutment15closest to the central part of the microsystem1, equivalently to what is illustrated inFIGS.1A and1B.

Relative to this or these lateral abutments15, the pin122can extend, opposite the cavity13, beyond (seeFIG.1B) or below (seeFIG.1A). At least one lateral abutment15can also be configured to enable the guiding and the self-positioning of the external member2on the electromechanical microsystem1. It also contributes to limiting, even removing, the risk of tearing of the deformable membrane12during the transfer of the external member2onto the electromechanical microsystem1. In this case, it is noted that, depending on the extent of the external member2, at least one lateral abutment15can also play the role of a top abutment limiting the moving closer of the external member2towards the electromechanical microsystem1.

This particularity can also make it possible to induce a disconnection of the pin122and of the external member2from one another by pulling the pin122into a lower position that possibly reached by the external member2due to the latter abutting on the top of the lateral abutment15. More specifically, the lateral abutment15has an abutment surface configured to stop the movement of the member2. The electromechanical microsystem1is configured such that when the movement of the member2is stopped in its movement, in a given direction, by the lateral abutment15, the pin122can continue its movement, in this same direction. The pin122is thus disconnected from the member2.

As illustrated in each of theFIGS.1A and1B, the electromechanical microsystem1can further comprise one or more so-called bottom abutments16supported by the wall132of the cavity13which is opposite the wall131formed at least partially by the deformable membrane12and extending into the cavity13towards the free zone121of the membrane12. This bottom abutment16preferably has a shape and dimensions configured to limit the deformation of the free zone121of the membrane12so as to protect the membrane12, and more specifically, its free zone121, from a possible tearing, in particular during the transfer of the external member2onto the electromechanical microsystem1.

Alternatively or cumulatively, the bottom abutment16can be shaped so as to limit the contact surface between the membrane12and the wall132of the cavity13opposite the free zone121of the deformable membrane12. This makes it possible to avoid the membrane12not adhering and not bonding to this wall132.

Embodiments of the invention more specific than those described above are illustrated inFIGS.2A and2B, in which the same references as inFIGS.1A and1Breference the same objects.

First, it is observed there that each electromechanical transducer11illustrated comprises a beam305and a piezoelectric material302configured to deform the beam305when it is crossed by an electrical current.

A comparison betweenFIGS.2A and2Bshows that the piezoelectric material302can be located on one side or the other of a neutral fibre of the assembly constituting the electromechanical transducer11. It is thanks to this alternative that a ferroelectric piezoelectric material, the deformation of which is preferably independent of the polarisation of the electrical current crossing it, all the same makes it possible to deform the beam305in one direction or in the other.

More specifically, inFIG.2A, the piezoelectric material302is located under the beam305, and therefore under the neutral fibre of the assembly, i.e. that it is located between the beam305and the membrane12. When an electrical voltage is applied on the piezoelectric material302, it is retracted and drives the beam305with it. A free end305aof the beam is curved downwards, driving a part of the zone123of the membrane2with it, which is linked to the beam305. By preservation of volume, the free zone121of the membrane12is itself moved upwards, thus driving the movement upwards of the pin122with it. This scenario corresponds to that illustrated inFIG.1A. Another end305bof the beam302preferably remains fixed. This other end305b, is for example, integral with a fixed wall of the cavity13, which is constituted of the spacer306and/or of the lateral abutment15located facing one another. In this sense, it can be provided that the lateral abutment15forms all or some of a cap of the electromechanical microsystem1, the cap having the role of ensuring the engagement of the end305bof the beam302.

InFIG.2B, the piezoelectric material302is located above the beam305, i.e. that the beam305is located between the piezoelectric material302and the membrane12. When a voltage is applied on the piezoelectric material302, it is retracted and drives the beam305with it. A free end305aof the beam thus bends upwards, pulling a part of the zone123of the membrane12with it, which is linked to the beam305. By preservation of volume, the free zone121of the membrane is itself moved downwards, thus driving the movement downwards of the pin122with it. This scenario corresponds to that illustrated inFIG.1B.

The different heights that the pin122can have relative to the height of the lateral abutments15are also observed inFIGS.2A and2B. There, it is only also observed that the lateral abutments15and the bottom abutments16, and/or their cross-section, can take different shapes, and in particular a parallelepiped shape, a truncated shape, a substantially pyramidal shape, etc.

It is further observed, inFIGS.2A and2B, that the moveable part111of the electromechanical transducer11can be defined by the extent of the piezoelectric material302relative to the extent of the beam305.

InFIGS.2A and2B, access openings for an electrical connection of the electrodes are represented. These openings form vias17in these examples. In this example, the vias17pass through the whole thickness of the beam305and the whole thickness between the lateral abutments15. In this case, it is noted that the lateral abutments such as illustrated inFIGS.2A and2Bcan each form a ring and conserve a via17between them, itself taking the shape of a ring; alternatively, the lateral abutments15can also only form one single ring in the thickness of which at least one via17, for example cylindrically-shaped, would be formed. The thickness e305of the beam302is measured in a direction perpendicular to the plane, wherein the faces12eand12iof the membrane12mainly extend at rest. The thickness e305is referenced inFIGS.2A and2B.

FIGS.2A and2Billustrate more specifically, third and fourth embodiments of the invention which have been obtained by etching and deposition steps which could be qualified as ordinary in the microelectronics field. More specifically, the electromechanical microsystem1according to the third embodiment illustrated inFIG.2Ahas been obtained by the succession of steps illustrated byFIGS.3A,4A,5A,6A,7A,8A and9Aand the electromechanical microsystem1according to the fourth embodiment illustrated inFIG.2Bhas been obtained by the succession of steps illustrated byFIGS.3B,4B,5B,6B,7B,8B and9B. Thus, two manufacturing methods are illustrated, which each lead to one of the electromechanical microsystems1illustrated inFIGS.2A and2B.

These manufacturing methods have, at least in common, to comprise:a. a formation step from which is intended to constitute at least one portion of the electromechanical transducer11on a substrate200, thenb. a step of depositing the deformable membrane12, thenc. a step of forming a cavity13open on the deformable membrane13, thend. a step of filling with the deformable medium and of closing the cavity13, ande. a step of etching the substrate200to form the front face of the electromechanical microsystems illustrated inFIGS.2A and2B.

Below, successively each of the abovementioned manufacturing methods are described, starting with the method for manufacturing the electromechanical microsystem1such as illustrated inFIG.2A.

The first step of this method is illustrated inFIG.3A. It consists of providing a substrate200on which a stack of layers extends, which can successively comprise, from a face of the substrate200:a. a first insulating layer201, for example silicon oxide-based, which could be deposited by plasma-enhanced chemical vapour deposition (PECVD),b. a layer202intended to constitute the beam305of the electromechanical transducer11, this layer202being, for example, amorphous, polycrystalline or monocrystalline silicon-based, and which could be deposited by chemical vapour deposition (CVD), or low pressure chemical vapour deposition (LPCVD), or by using an SOI (silicon on insulator)-type structure,c. a second insulating layer203, for example, silicon oxide-based, and which could be deposited by PECVD,d. a layer204intended to constitute a so-called lower electrode, for example platinum-based and which could be deposited by physical vapour deposition (PVD),e. a layer205made of a piezoelectric material, for example PZT-based, and which could be deposited by a sol-gel method, andf. a layer206intended to constitute a so-called upper electrode, for example platinum-based and which could be deposited by PVD.

The second step of the method for manufacturing the electromechanical microsystem1such as illustrated inFIG.2Ais illustrated inFIG.4A. It comprises:a. an etching of the layer206, so as to form the upper electrode301of the electromechanical transducer11,b. an etching of the layer205, so as to form the piezoelectric elements302of the electromechanical transducer11, andc. an etching of the layer204, so as to form the lower electrode303of the electromechanical transducer11.

It is noted that each of these etchings can be done by lithography, and preferably by plasma etching, or by wet chemical etching.

The third step of the method for manufacturing the electromechanical microsystem1such as illustrated inFIG.2Ais illustrated inFIG.5A. It comprises:a. the deposition of a passivation layer207, for example silicon oxide- and/or silicon nitride-based, which could be deposited by PECVD,b. the opening, through the passivation layer207, of an electrode contact zone, this opening being achieved, for example, by lithography, and preferably by plasma etching, or by wet chemical etching,c. the deposition of a layer intended to constitute one electrical line304per electrode, the layer being, for example, gold-based, and which could be deposited by PVD, andd. an etching of the layer previously deposited so as to form one electrical line304per electrode, this etching being done, for example, by lithography, and preferably by plasma etching, or by wet chemical etching.

The fourth step of the method for manufacturing the electromechanical microsystem1such as illustrated inFIG.2Ais illustrated inFIG.6A. It comprises the deposition of a layer208with the basis of a polymer and intended to constitute the deformable membrane12. This layer208is, for example, deposited by spin coating. The polymer with the basis of which the layer208is constituted is, for example, PDMS-based.

The fifth step of the method for manufacturing the electromechanical microsystem1such as illustrated inFIG.2Ais illustrated inFIG.7A. It comprises the formation of at least one spacer306intended to constitute at least one part of said at least one side wall133of the cavity13. The formation of the spacer(s) can comprise the lamination of a photosensitive material with the basis of which the spacer(s) is/are constituted, the insulation, then the development of the photosensitive material. Said photosensitive material can be with the basis of a polymer, and in particular siloxane-based. The lamination of the photosensitive material can comprise the lamination of a dry film of said material.

The sixth step of the method for manufacturing the electromechanical microsystem1such as illustrated inFIG.2Ais illustrated inFIG.8A. According to an optional embodiment, this step comprises the deposition of glue210at the top of each spacer306, this deposition could be done by screen printing or by dispensation. It comprises the fixing, for example the bonding, on the top of the spacer(s) (optionally by way of glue210), of a second substrate211which could be structured so as to comprise at least one from among a through vent212and a bottom abutment16, such as described above. In an alternative embodiment, according to the nature of the spacer, this can play the role of glue. Coming from this sixth step, the cavity13is formed which is open by at least one through vent212.

The seventh step of the method for manufacturing the electromechanical microsystem1such as illustrated inFIG.2Ais illustrated inFIG.9A. It comprises the filling, preferably under vacuum, of the cavity13with the deformable medium14such as described above, for example by dispensation through the through vent212. It also comprises the sealed closing of the through vent212, for example by dispensation of a sealing material213at the mouth of each through vent212, the sealing material213being, for example, with the basis of an epoxy glue.

An additional step makes it possible to obtain the electromechanical microsystem1such as illustrated inFIG.2A. It comprises the etching of the substrate200, then the etching of the layer202and of the insulating layers201,203, so as to form at least one beam305of the electromechanical transducer11, to expose a part of the deformable membrane12and to constitute all or some of the pin122and optional lateral abutments15. This additional step can be carried out by lithography, and preferably by plasma etching, or by wet chemical etching.

It is noted that, following the steps described above of manufacturing the electromechanical microsystem1, such as illustrated inFIG.2A, the pin122takes the form of a stack extending directly from the deformable membrane12opposite the cavity13by successively having the material of the insulating layer201, the material constituting the beam305, the material of the insulating layer203and the material constituting the substrate200. It is also noted that, following the steps described above of manufacturing the electromechanical microsystem1, such as illustrated inFIG.2A, the optional lateral abutments15each take the form of a stack extending, directly or indirectly, from the deformable membrane12opposite the cavity13by successively having the material of the insulating layer201, the material constituting the beam305, the material of the insulating layer203and the material constituting the substrate200.

The method for manufacturing the electromechanical microsystem1, such as illustrated inFIG.2Bis described below.

The first step of this method is illustrated inFIG.3B. It consists of providing a substrate400on which a stack of layers extends which can successively comprise, from a face of the substrate400:a. a first insulating layer401, for example, silicon oxide-based, which could be deposited by plasma-enhanced chemical vapour deposition (PECVD),b. a layer402intended to constitute a so-called lower electrode, for example platinum-based and which could be deposited by PVD,c. a layer403made of a piezoelectric material, for example PZT-based, and could be deposited by a sol-gel method, andd. a layer404intended to constitute a so-called upper electrode, for example platinum-based and which could be deposited by PVD.

The second step of the method for manufacturing the electromechanical microsystem1, such as illustrated inFIG.2Bis illustrated inFIG.4B. It comprises:a. an etching of the layer404so as to form the upper electrode301of the electromechanical transducer11,b. an etching of the layer403so as to form the piezoelectric elements302of the electromechanical transducer11, andc. an etching of the layer402so as to form the lower electrode303of the electromechanical transducer11.

It is noted that each of these etchings can be done by lithography, and preferably by plasma etching, or by wet chemical etching.

The third step of the method for manufacturing the electromechanical microsystem1, such as illustrated inFIG.2Bis illustrated inFIG.5B. It comprises:a. the deposition of a passivation layer405, for example, silicon oxide- and/or silicon nitride-based, which could be deposited by PECVD,b. the opening, through the passivation layer405, of an electrode contact zone, this opening being achieved, for example, by lithography, and preferably by plasma etching, or by wet chemical etching,c. the deposition of a layer intended to constitute one electrical line304per electrode, the layer being, for example, gold-based and which could be deposited by PVD,d. an etching of the layer previously deposited, so as to form one electrical line304per electrode, this etching being done, for example, by lithography, and preferably by plasma etching, or by wet chemical etching, thene. the deposition of a passivation layer406, for example, silicon oxide- and/or silicon nitride-based, which could be deposited by PECVD.

The fourth step of the method for manufacturing the electromechanical microsystem1, such as illustrated inFIG.2Bis illustrated inFIG.6B. It comprises the deposition of a layer intended to constitute the beam305of the electromechanical transducer11, this layer being, for example, amorphous silicon-based and could be deposited by PVD. It can then comprise a step of flattening the layer previously deposited. It then comprises an etching of the layer previously deposited so as to form at least one beam305of the electromechanical transducer11. This etching being done, for example, by lithography, and preferably by plasma etching, or by wet chemical etching.

The fifth step of the method for manufacturing the electromechanical microsystem1, such as illustrated inFIG.2Bis illustrated inFIG.7B. It comprises:a. the deposition of a layer407with the basis of a polymer and intended to constitute the deformable membrane12; this layer407is, for example, deposited by spin coating. The polymer with the basis of which the layer407is constituted, is, for example, PDMS-based, andb. the formation of at least one spacer306intended to constitute at least one part of said at least one side wall133of the cavity13.

The formation of the spacer(s)306can comprise the lamination of a photosensitive material with the basis of which the spacer(s) is/are constituted, the insolation, then the development of the photosensitive material. Said photosensitive material can be with the basis of a polymer, and in particular, siloxane-based. The lamination of the photosensitive material can comprise the lamination of a dry film of said material.

The sixth step of the method for manufacturing the electromechanical microsystem1, such as illustrated inFIG.2Bis illustrated inFIG.8B. It comprises, if necessary, the deposition of glue408at the top of each spacer306. According to an optional example, this deposition can be done by screen printing or by dispensation. It comprises the bonding, on the top of the spacer(s)306(optionally by way of the glue408), of a second substrate411which could be structured, so as to comprise at least one from among a through vent412and a bottom abutment16, such as described above. In an alternative embodiment, according to the nature of the spacer, this can play the role of glue. Coming from this sixth step, the cavity13is formed which is open by at least one through vent412.

The seventh step of the method for manufacturing the electromechanical microsystem1, such as illustrated inFIG.2Bis illustrated inFIG.9B. It comprises the filling, preferably under vacuum, of the cavity13with the deformable medium14, such as described above, for example, by dispensation through the at least one through vent212. It also comprises the sealed closing of the at least one through vent212, for example, by dispensation of a sealing material213at least at the mouth of each through vent212, the sealing material213being, for example, with the basis of an epoxy glue.

An additional step makes it possible to obtain the electromechanical microsystem1, such as illustrated inFIG.2B. It comprises the etching of the substrate400, then the etching of the insulating layer401, so as to expose a part of the deformable membrane12and to constitute all or some of the pin122, and optional lateral abutments15. This additional step can be carried out by lithography, and preferably by plasma etching, or by wet chemical etching.

It is noted that, following the steps described above of manufacturing the electromechanical microsystem1, such as illustrated inFIG.2B, the pin122takes the form of a stack extending directly from the deformable membrane12opposite the cavity13by successively having the material of the insulating layer401and the material constituting the substrate400. It is also noted that, following the steps described above of manufacturing the electromechanical microsystem1, such as illustrated inFIG.2B, the optional lateral abutments15each take the form of a stack extending, directly or indirectly, from the beam305opposite the cavity13by successively having the material of the insulating layer401and the material constituting the substrate400.

Another aspect of the invention relates to an opto-electromechanical system3, such as illustrated inFIGS.10,11A and11B. This can be an opto-electromechanical microsystem3. Each of the opto-electromechanical microsystems3illustrated in these figures comprises at least one electromechanical microsystem1, such as described above and at least one optical microsystem31. Said at least one electromechanical microsystem1is preferably mounted on a support32of the opto-electromechanical microsystem3. Said at least one optical microsystem31can comprise a silicon-based micro-mirror, the surface of which is, if necessary, surmounted by at least one mirror. It can be mounted directly on said at least one electromechanical microsystem1, or be mounted there by way of a frame33. It can have dimensions substantially equal to 2 mm×5 mm and/or, as a maximum, a thickness of around 700 μm. The opto-electromechanical microsystems3, such as illustrated, each comprise four electromechanical microsystems1, each having a free zone121arranged opposite a part of one same optical microsystem31. Thus, an opto-electromechanical microsystem1is obtained, benefiting from a wide capacity to adapt its optical orientation.

The invention is not limited to the embodiments described above, and extends to all the embodiments covered by the claims.

In particular, applications other than those described above can be considered. For example, the electromechanical microsystem1can be arranged in a micropump, even in a micropump table system, in a haptic system.